inventory management ii lot sizing lecture 5 esd.260 fall 2003 caplice

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Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

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Page 1: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Inventory Management II Lot Sizing

Lecture 5ESD260 Fall 2003

Caplice

Outline

EOQ Model

Sensitivity Analysis

Discounting1048708

All Units1048708

Incremental1048708

One Time Special

MIT Center for Transportation amp Logistics - ESD260 2 copy Chris Caplice MIT

Assumptions Basic EOQ Model Demand1048708 Constant vs Variable1048708 Known vs Random1048708 Continuous vs Discrete Lead time Instantaneous1048708 Constant or Variable (deterministicstochastic) Dependence of items 1048708 Independent Correlated1048708 Indentured 1048708 Review Time Continuous vs Periodic Number of Echelons1048708 One vs Many Capacity Resources1048708 Unlimited vs Limited

Discounts1048708 None1048708 All Units or Incremental Excess Demand1048708 None1048708 All orders are backordered1048708 Lost orders1048708 Substitution Perishability1048708 None1048708 Uniform with time Planning Horizon1048708 Single Period1048708 Finite Period1048708 Infinite Number of Items1048708 One1048708 Many

MIT Center for Transportation amp Logistics - ESD260 3 copy Chris Caplice MIT

Notation

TC = Total Cost (dollartime) D = Average Demand (unitstime) Co = Ordering Cost (dollarorder) Ch = Holding Cost (dollarsdollars heldtime) Cp = Purchase Cost (dollarsunit) Q = Order Quantity (unitsorder) T = Order Cycle Time (timeorder)

MIT Center for Transportation amp Logistics - ESD260 4 copy Chris Caplice MIT

Lot Sizing Many Potential Policies

MIT Center for Transportation amp Logistics - ESD260 5 copy Chris Caplice MIT

Inve

nto

ry O

n H

and

Time

Objective Pick the policy with the lowest total cost

I(t)

What is the total cost

TC = Purchase + Order + Holding + Shortage Cost

Which costs are relevant Purchase Costs

Ordering Costs

Holding Costs

Shortage Costs

MIT Center for Transportation amp Logistics - ESD260 6 copy Chris Caplice MIT

02

( ) h pQD

QTC Q C C C

Economic Order Quantity (EOQ)

0[ ]

2

h pC D C C QTC Q

Q

02

h p

DCQ

C C

MIT Center for Transportation amp Logistics - ESD260 7 copy Chris Caplice MIT

0 2 h pTC DC C C

Simple EOQ Example

Annual demand of widgets is 2000 The cost of ordering is $500 Widgets are procured for $50 each and are sold for $95 each Holding cost is estimated to be 25

What is the EOQ Total Cost and Cycle Time

Q = 400 units TC = $5000 year T = 020 years or 73 days

MIT Center for Transportation amp Logistics - ESD260 8 copy Chris Caplice MIT

Total Cost versus Lot (Order) Size

MIT Center for Transportation amp Logistics - ESD260 9 copy Chris Caplice MIT

Lot Size

Ann

ual

Cos

t

Annual Cost vs Order Quantity

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 2: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Outline

EOQ Model

Sensitivity Analysis

Discounting1048708

All Units1048708

Incremental1048708

One Time Special

MIT Center for Transportation amp Logistics - ESD260 2 copy Chris Caplice MIT

Assumptions Basic EOQ Model Demand1048708 Constant vs Variable1048708 Known vs Random1048708 Continuous vs Discrete Lead time Instantaneous1048708 Constant or Variable (deterministicstochastic) Dependence of items 1048708 Independent Correlated1048708 Indentured 1048708 Review Time Continuous vs Periodic Number of Echelons1048708 One vs Many Capacity Resources1048708 Unlimited vs Limited

Discounts1048708 None1048708 All Units or Incremental Excess Demand1048708 None1048708 All orders are backordered1048708 Lost orders1048708 Substitution Perishability1048708 None1048708 Uniform with time Planning Horizon1048708 Single Period1048708 Finite Period1048708 Infinite Number of Items1048708 One1048708 Many

MIT Center for Transportation amp Logistics - ESD260 3 copy Chris Caplice MIT

Notation

TC = Total Cost (dollartime) D = Average Demand (unitstime) Co = Ordering Cost (dollarorder) Ch = Holding Cost (dollarsdollars heldtime) Cp = Purchase Cost (dollarsunit) Q = Order Quantity (unitsorder) T = Order Cycle Time (timeorder)

MIT Center for Transportation amp Logistics - ESD260 4 copy Chris Caplice MIT

Lot Sizing Many Potential Policies

MIT Center for Transportation amp Logistics - ESD260 5 copy Chris Caplice MIT

Inve

nto

ry O

n H

and

Time

Objective Pick the policy with the lowest total cost

I(t)

What is the total cost

TC = Purchase + Order + Holding + Shortage Cost

Which costs are relevant Purchase Costs

Ordering Costs

Holding Costs

Shortage Costs

MIT Center for Transportation amp Logistics - ESD260 6 copy Chris Caplice MIT

02

( ) h pQD

QTC Q C C C

Economic Order Quantity (EOQ)

0[ ]

2

h pC D C C QTC Q

Q

02

h p

DCQ

C C

MIT Center for Transportation amp Logistics - ESD260 7 copy Chris Caplice MIT

0 2 h pTC DC C C

Simple EOQ Example

Annual demand of widgets is 2000 The cost of ordering is $500 Widgets are procured for $50 each and are sold for $95 each Holding cost is estimated to be 25

What is the EOQ Total Cost and Cycle Time

Q = 400 units TC = $5000 year T = 020 years or 73 days

MIT Center for Transportation amp Logistics - ESD260 8 copy Chris Caplice MIT

Total Cost versus Lot (Order) Size

MIT Center for Transportation amp Logistics - ESD260 9 copy Chris Caplice MIT

Lot Size

Ann

ual

Cos

t

Annual Cost vs Order Quantity

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 3: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Assumptions Basic EOQ Model Demand1048708 Constant vs Variable1048708 Known vs Random1048708 Continuous vs Discrete Lead time Instantaneous1048708 Constant or Variable (deterministicstochastic) Dependence of items 1048708 Independent Correlated1048708 Indentured 1048708 Review Time Continuous vs Periodic Number of Echelons1048708 One vs Many Capacity Resources1048708 Unlimited vs Limited

Discounts1048708 None1048708 All Units or Incremental Excess Demand1048708 None1048708 All orders are backordered1048708 Lost orders1048708 Substitution Perishability1048708 None1048708 Uniform with time Planning Horizon1048708 Single Period1048708 Finite Period1048708 Infinite Number of Items1048708 One1048708 Many

MIT Center for Transportation amp Logistics - ESD260 3 copy Chris Caplice MIT

Notation

TC = Total Cost (dollartime) D = Average Demand (unitstime) Co = Ordering Cost (dollarorder) Ch = Holding Cost (dollarsdollars heldtime) Cp = Purchase Cost (dollarsunit) Q = Order Quantity (unitsorder) T = Order Cycle Time (timeorder)

MIT Center for Transportation amp Logistics - ESD260 4 copy Chris Caplice MIT

Lot Sizing Many Potential Policies

MIT Center for Transportation amp Logistics - ESD260 5 copy Chris Caplice MIT

Inve

nto

ry O

n H

and

Time

Objective Pick the policy with the lowest total cost

I(t)

What is the total cost

TC = Purchase + Order + Holding + Shortage Cost

Which costs are relevant Purchase Costs

Ordering Costs

Holding Costs

Shortage Costs

MIT Center for Transportation amp Logistics - ESD260 6 copy Chris Caplice MIT

02

( ) h pQD

QTC Q C C C

Economic Order Quantity (EOQ)

0[ ]

2

h pC D C C QTC Q

Q

02

h p

DCQ

C C

MIT Center for Transportation amp Logistics - ESD260 7 copy Chris Caplice MIT

0 2 h pTC DC C C

Simple EOQ Example

Annual demand of widgets is 2000 The cost of ordering is $500 Widgets are procured for $50 each and are sold for $95 each Holding cost is estimated to be 25

What is the EOQ Total Cost and Cycle Time

Q = 400 units TC = $5000 year T = 020 years or 73 days

MIT Center for Transportation amp Logistics - ESD260 8 copy Chris Caplice MIT

Total Cost versus Lot (Order) Size

MIT Center for Transportation amp Logistics - ESD260 9 copy Chris Caplice MIT

Lot Size

Ann

ual

Cos

t

Annual Cost vs Order Quantity

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 4: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Notation

TC = Total Cost (dollartime) D = Average Demand (unitstime) Co = Ordering Cost (dollarorder) Ch = Holding Cost (dollarsdollars heldtime) Cp = Purchase Cost (dollarsunit) Q = Order Quantity (unitsorder) T = Order Cycle Time (timeorder)

MIT Center for Transportation amp Logistics - ESD260 4 copy Chris Caplice MIT

Lot Sizing Many Potential Policies

MIT Center for Transportation amp Logistics - ESD260 5 copy Chris Caplice MIT

Inve

nto

ry O

n H

and

Time

Objective Pick the policy with the lowest total cost

I(t)

What is the total cost

TC = Purchase + Order + Holding + Shortage Cost

Which costs are relevant Purchase Costs

Ordering Costs

Holding Costs

Shortage Costs

MIT Center for Transportation amp Logistics - ESD260 6 copy Chris Caplice MIT

02

( ) h pQD

QTC Q C C C

Economic Order Quantity (EOQ)

0[ ]

2

h pC D C C QTC Q

Q

02

h p

DCQ

C C

MIT Center for Transportation amp Logistics - ESD260 7 copy Chris Caplice MIT

0 2 h pTC DC C C

Simple EOQ Example

Annual demand of widgets is 2000 The cost of ordering is $500 Widgets are procured for $50 each and are sold for $95 each Holding cost is estimated to be 25

What is the EOQ Total Cost and Cycle Time

Q = 400 units TC = $5000 year T = 020 years or 73 days

MIT Center for Transportation amp Logistics - ESD260 8 copy Chris Caplice MIT

Total Cost versus Lot (Order) Size

MIT Center for Transportation amp Logistics - ESD260 9 copy Chris Caplice MIT

Lot Size

Ann

ual

Cos

t

Annual Cost vs Order Quantity

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
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  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 5: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Lot Sizing Many Potential Policies

MIT Center for Transportation amp Logistics - ESD260 5 copy Chris Caplice MIT

Inve

nto

ry O

n H

and

Time

Objective Pick the policy with the lowest total cost

I(t)

What is the total cost

TC = Purchase + Order + Holding + Shortage Cost

Which costs are relevant Purchase Costs

Ordering Costs

Holding Costs

Shortage Costs

MIT Center for Transportation amp Logistics - ESD260 6 copy Chris Caplice MIT

02

( ) h pQD

QTC Q C C C

Economic Order Quantity (EOQ)

0[ ]

2

h pC D C C QTC Q

Q

02

h p

DCQ

C C

MIT Center for Transportation amp Logistics - ESD260 7 copy Chris Caplice MIT

0 2 h pTC DC C C

Simple EOQ Example

Annual demand of widgets is 2000 The cost of ordering is $500 Widgets are procured for $50 each and are sold for $95 each Holding cost is estimated to be 25

What is the EOQ Total Cost and Cycle Time

Q = 400 units TC = $5000 year T = 020 years or 73 days

MIT Center for Transportation amp Logistics - ESD260 8 copy Chris Caplice MIT

Total Cost versus Lot (Order) Size

MIT Center for Transportation amp Logistics - ESD260 9 copy Chris Caplice MIT

Lot Size

Ann

ual

Cos

t

Annual Cost vs Order Quantity

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
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  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 6: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

What is the total cost

TC = Purchase + Order + Holding + Shortage Cost

Which costs are relevant Purchase Costs

Ordering Costs

Holding Costs

Shortage Costs

MIT Center for Transportation amp Logistics - ESD260 6 copy Chris Caplice MIT

02

( ) h pQD

QTC Q C C C

Economic Order Quantity (EOQ)

0[ ]

2

h pC D C C QTC Q

Q

02

h p

DCQ

C C

MIT Center for Transportation amp Logistics - ESD260 7 copy Chris Caplice MIT

0 2 h pTC DC C C

Simple EOQ Example

Annual demand of widgets is 2000 The cost of ordering is $500 Widgets are procured for $50 each and are sold for $95 each Holding cost is estimated to be 25

What is the EOQ Total Cost and Cycle Time

Q = 400 units TC = $5000 year T = 020 years or 73 days

MIT Center for Transportation amp Logistics - ESD260 8 copy Chris Caplice MIT

Total Cost versus Lot (Order) Size

MIT Center for Transportation amp Logistics - ESD260 9 copy Chris Caplice MIT

Lot Size

Ann

ual

Cos

t

Annual Cost vs Order Quantity

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 7: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Economic Order Quantity (EOQ)

0[ ]

2

h pC D C C QTC Q

Q

02

h p

DCQ

C C

MIT Center for Transportation amp Logistics - ESD260 7 copy Chris Caplice MIT

0 2 h pTC DC C C

Simple EOQ Example

Annual demand of widgets is 2000 The cost of ordering is $500 Widgets are procured for $50 each and are sold for $95 each Holding cost is estimated to be 25

What is the EOQ Total Cost and Cycle Time

Q = 400 units TC = $5000 year T = 020 years or 73 days

MIT Center for Transportation amp Logistics - ESD260 8 copy Chris Caplice MIT

Total Cost versus Lot (Order) Size

MIT Center for Transportation amp Logistics - ESD260 9 copy Chris Caplice MIT

Lot Size

Ann

ual

Cos

t

Annual Cost vs Order Quantity

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 8: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Simple EOQ Example

Annual demand of widgets is 2000 The cost of ordering is $500 Widgets are procured for $50 each and are sold for $95 each Holding cost is estimated to be 25

What is the EOQ Total Cost and Cycle Time

Q = 400 units TC = $5000 year T = 020 years or 73 days

MIT Center for Transportation amp Logistics - ESD260 8 copy Chris Caplice MIT

Total Cost versus Lot (Order) Size

MIT Center for Transportation amp Logistics - ESD260 9 copy Chris Caplice MIT

Lot Size

Ann

ual

Cos

t

Annual Cost vs Order Quantity

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 9: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Total Cost versus Lot (Order) Size

MIT Center for Transportation amp Logistics - ESD260 9 copy Chris Caplice MIT

Lot Size

Ann

ual

Cos

t

Annual Cost vs Order Quantity

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 10: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

The Effect of Non-Optimal Q

Q DCoQ ChCpQ2 TC

2000 $500 $12500 $13000

500 $2000 $3125 $5125

400 $2500 $2500 $5000

200 $5000 $1250 $6250

20 $50000 $125 $50125

MIT Center for Transportation amp Logistics - ESD260 10 copy Chris Caplice MIT

So how sensitive is TC to Q

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 11: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Sensitivity of EOQ

How does TC change with Q

02

( ) h pQD

QTC Q C C C

0( ) 2 p hTC Q C C C D

( ) 1

( ) 2

TC Q Q Q

TC Q Q Q

MIT Center for Transportation amp Logistics - ESD260 11 copy Chris Caplice MIT

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 12: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Sensitivity of EOQ

Sensitivity TC wrt Q

MIT Center for Transportation amp Logistics - ESD260 12 copy Chris Caplice MIT

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 13: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Sensitivity of EOQ

What if our estimate of demand was off E = Actual Demand Estimated Demand

Qrsquo = Estimated EOQ

Q = Actual EOQ given actual demand that occurred

D ActualE

D Estimate 02

h p

D CQ

C C

QE

Q

1

2

TC E

TC E

MIT Center for Transportation amp Logistics - ESD260 13 copy Chris Caplice MIT

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 14: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Sensitivity of EOQ to Parameter Error

So for Drsquo = 2000 unitsyear if the

actual demand was hellip

D E QQ TCTC

200 010 032 174

1000 050 071 106

1500 075 087 101

1800 090 095 100

2000 100 100 100

3000 150 122 102

4000 200 141 106

20000 1000 316 174

MIT Center for Transportation amp Logistics - ESD260 14 copy Chris Caplice MIT

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 15: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Insights from EOQ

There is a direct trade off between lot size and total inventory

Total cost is relatively insensitive to changes

Very robust with respect to changes in Q ndashrounding of order quantities1048708 D ndasherrors in forecasting1048708

Ch Co Cp ndasherrors in cost parameters

Thus EOQ is widely used despite its highly restrictive assumptions

MIT Center for Transportation amp Logistics - ESD260 15 copy Chris Caplice MIT

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 16: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Introduce Discounts to Lot Sizing Types

Types of discounts1048708

All units discount1048708

Incremental discount1048708

One time only discount

How will different discounting strategies impact your lot sizing decision

MIT Center for Transportation amp Logistics - ESD260 16 copy Chris Caplice MIT

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 17: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

All Units Discount

Unit Price

[Cpi ]

Price Break Quantity

[PBQI]

$5000 0

$4500 500

$4000 1000

MIT Center for Transportation amp Logistics - ESD260 17 copy Chris Caplice MIT

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 18: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

All Units Discount

Need to introduce purchase cost into TC function

MIT Center for Transportation amp Logistics - ESD260 18 copy Chris Caplice MIT

0

2

h pipi pi

C D C C QTC Q C DC

Q

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 19: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 19 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 20: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

All Units Discount

Annual Costs

MIT Center for Transportation amp Logistics - ESD260 20 copy Chris Caplice MIT

Do

llar

s

Lot Size

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 21: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

All Units Discount MethodSame Example

D=2000 Unitsyr

Ch=25

Co=$500

CpiPrice Breaks $50 for 0 to lt500 units $45 for 500 to lt1000 units $40 for 1000+ units

MIT Center for Transportation amp Logistics - ESD260 21 copy Chris Caplice MIT

1 Cpi $4000 $4500 $5000

2 PBQ 1000 500 0

3 EOQ[Cpi] 447 421 400

4 Qpi 1000 500 400

5 DCpi $80000 $90000 $100000

6 C0DQpi $1000 $1000 $2500

7 ChCpiQpi2 $5000 $5000 $2500

8 TC[Qpi] $86000 $94812 $105000

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 22: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Incremental Discount

Treatment of the Incremental DiscountCost of Each Unit in the Lot

Cost of the Unit

Lot UnitMIT Center for Transportation amp Logistics - ESD260 22 copy Chris Caplice MIT

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 23: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 23 copy Chris Caplice MIT

Annual Cost

Lot Size

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 24: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

Incremental Discount

MIT Center for Transportation amp Logistics - ESD260 24 copy Chris Caplice MIT

Index i=3 i=2 i=1

1 Cpi $4000 $4500 $5000

2 PBQi 1000 500 0

3 Fi $7500 $2500 $0

4 EOQ[Cpi] 1789 1033 400

5 Qpi 1789 400

6 Cpe $4419 $5000

7 DCpe $8838457 $100000

8 CoDQpi $55897 $2500

9 (Ch C pe Qpi)2 $988250 $2500

10 TC[Qpi] $9882604 $105000

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 25: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 25 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
  • Slide 9
  • Slide 10
  • Slide 11
  • Slide 12
  • Slide 13
  • Slide 14
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Slide 22
  • Slide 23
  • Slide 24
  • Slide 25
  • Slide 26
  • Slide 27
  • Slide 28
  • Slide 29
Page 26: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 26 copy Chris Caplice MIT

Let 1048708 Cpg= One time deal purchase price ($unit)1048708 Qg= One time special order quantity (units)1048708 TCsp=TC over time covered by special purchase ($)

Then

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

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Page 27: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

One Time Discount

02

g gsp g pg g h pg

Q QTC Q D C Q C C C

D

MIT Center for Transportation amp Logistics - ESD260 27 copy Chris Caplice MIT

0

2 2

g ww w w gnsp g pg w p g w h pg h p

w

Q QQ Q Q QTC Q D C Q C Q Q C C C C C

D D Q

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
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  • Slide 29
Page 28: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

One Time Discount

p pg p wg

pg h pg

C C D C QQ

C C C

MIT Center for Transportation amp Logistics - ESD260 28 copy Chris Caplice MIT

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
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  • Slide 28
  • Slide 29
Page 29: Inventory Management II Lot Sizing Lecture 5 ESD.260 Fall 2003 Caplice

One Time Discount

MIT Center for Transportation amp Logistics - ESD260 29 copy Chris Caplice MIT

A quick numerical example

D = 2000 units year Co= $50000 order Ch= 25 Cp= $5000 uni Q = 400 units TC = $500000 year

Cpg= $4500 unit Qg= 1333 Savings = $244825

  • Slide 1
  • Slide 2
  • Slide 3
  • Slide 4
  • Slide 5
  • Slide 6
  • Slide 7
  • Slide 8
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