05 facilities layout

7/31/2019 05 Facilities Layout

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Session

5FacilityLayout


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Define layout planning and explain its importance

Identify and describe different types of layouts Compare process layouts & product layouts

Describe the steps involved in designing a process

layout

Describe the steps involved in designing a product

layout

Explain the advantages of hybrid layouts

Define the meaning of group technology (cell) layouts


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Higher utilization of space, equipment, and people

Improved flow of information, materials, or people

Improved employee morale and safer working

conditions

Improved customer/client interaction

Flexibility


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Material handling equipment

Capacity and space requirements

Environment and aesthetics

Flows of information

Cost of moving between various work areas


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The objective of layout strategy is to develop a cost-

effective layout that will meet a firms competitive

needs

Layout planning is determining the best physical

arrangement of resources within a facility

Facility resource arrangement can significantly affectproductivity

Two broad categories of operations:

Intermittent processing systems low volume of

many different products Continuous processing systems high volume of a

few standardized products


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Four basic layout types consisting of;

Process layouts Group similar resources together Product layoutsDesigned to produce a specific

product efficiently

Cell layoutsOrganizes people & machines into a

group Fixed-Position layoutsProduct is too large to

move; e.g. a building


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Equipment that perform similar processes are grouped

together

Used when the operations system must handle a wide

variety of products in relatively small volumes (i.e.,

flexibility is necessary)


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Advantages of process layouts include

general purpose & flexible resources

a lower investment in equipment, and

diversity of jobs inherent in a process layout can lead

to increased worker satisfaction.

Disadvantages include

high movement and transportation costs,

more complicated planning and control systems,

longer total processing time,

higher in-process inventory or waiting time,

higher worker-skill requirements, and Space requirements are higher.


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Operations are arranged in the sequence required to

make the product

Used when the operations system must handle a narrow

variety of products in relatively high volumes

Operations and personnel are dedicated to producing one

or a small number of products


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Advantages of product layouts include

lower work-in-process inventories,

shorter processing times,

less material handling,

lower labor skills, and

simple planning and control systems.

Disadvantages include that

a breakdown at one workstation can cause the entire

process to shut down;

a change in product design or the introduction of new

products may require major changes in the layout, limiting flexibility.


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Operations required to produce a particular family

(group) of parts are arranged in the sequence required tomake that family

Used when the operations system must handle a

moderate variety of products in moderate volumes


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The Advantages are:

Reduced work in process inventory workcell is setupto provide one piece flow from machine to machine

Less floor space required because less space is needed

between machines to keep WIP inventory

Reduced direct labor

Heightened sense of employee participation Increased use of equipment and machinery

Reduced investment in machinery and equipment


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Product remains in a fixed position, and the personnel,

material and equipment come to it

Used when the product is very bulky, large, heavy or

fragile

Complicating factors

Limited space at site

Different materialsrequired at different

stages of the project

Volume of materials

needed is dynamic


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Step 1: Gather information:

Space needed, space available, importance ofproximity (closeness) between various units

Step 2: Develop alternative block plans:

Using trial-and-error or decision support tools

Step 3: Develop a detailed layout

Consider exact sizes and shapes of departments and

work centers including aisles and stairways

Tools like drawings, 3-D models, and CAD software

are available to facilitate this process


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Step 1: Gather information like space needed, from-to

matrix, and REL Chart for Recovery First Sports MedicineClinic (total space 3750 sq. ft.)

A

Radiology

400 sq. ft.

B

Laboratory

300 sq. ft.

C

Lobby &

Waiting300 sq. ft.

D

ExaminingRooms

800 sq. ft.

E

Surgery &Recovery

900 sq. ft.

F

PhysicalTherapy

1050 sq. ft.


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TableFrom-To Matrix

for Recovery First


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TableREL Chart for

Recovery First


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Step 2: Develop A New Block Layout Use trial and error with

From-To and REL Charts asa guide

Use computer softwarelike ALDEP or CRAFT

Table : Id Score Computations for Current and Proposed Layouts for Recovery First


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Decision Support Tools

Trial and error method good for simple problems Layout problems are combinatorial,

3x2 office layout has 6! Options (6*5*4*3*2*1 =

720 options)

Computer programs are available decision supporttools

ALDEP (Automated Layout Design Program) based

on REL (Relationship Layout) and CRAFT

(Computerized Relative Allocation of Facilities

Techniques) based on form-to matrix


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There are a number of unique process layouts which

include Warehouse layouts

Office Layouts


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Objective is to optimize trade-offs between handling costs

and costs associated with warehouse space

Maximize the total cube of the warehouse utilize its

full volume while maintaining low material handling costs

Warehouse density tends to vary inversely with the

number of different items stored

Automated Storage and

Retrieval Systems (ASRSs)

can significantly improve

warehouse productivity byan estimated 500%

Dock location is a key

design element


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The usage ofCrossdockingmodifies the traditional

warehouse layouts; more docks, less storage space, andless order picking

Materials are moved directly from receiving to shipping

and are not placed in storage

in the warehouse Requires tight

scheduling and

accurate shipments,

bar code or RFIDidentification used for

advanced shipment

notification as materials

are unloaded


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Human interaction and communication are the primary

factors in designing office layouts

Layouts need to account for physical environment and

psychological needs of the organization

One key layout trade-off is between proximity and

privacy

Open concept offices promote understanding & trust

Flexible layouts incorporating

office landscaping help tosolve the privacy issue in open

office environments


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Product layouts are different than process layouts

Product layouts provide for sequential product

movement that enhances efficiency

Designing product layouts requires consideration of

Sequence of tasks to be performed by each

workstation

Logical order

Speed considerations line balancing


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Step 1: Identify tasks & immediate predecessors

Step 2: Determine the desired output rate

Step 3: Calculate the cycle time

Step 4: Compute the theoretical minimum number of

workstations

Step 5: Assign tasks to workstations (balance the line)

Step 6: Compute efficiency, idle time & balance delay


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Step 1: Identify tasks & immediate predecessors

Wiley 2007

Example 10.4 Vicki's Pizzeria and the Precedence DiagramImmediate Task Time

Work Element Task Description Predecessor (secondsA Roll dough None 50

B Place on cardboard backing A 5

C Sprinkle cheese B 25

D Spread Sauce C 15

E Add pepperoni D 12

F Add sausage D 10G Add mushrooms D 15

H Shrinkwrap pizza E,F,G 18

I Pack in box H 15

Total task time 165


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Step 2: Determine output rate

Vicki needs to produce 60 pizzas per hour

Step 3:Determine cycle time

The amount of time each workstation is allowed to

complete its tasks

Limited by the bottleneck task (the longest task in a

process):

sec./unit60units/hr60

sec/min60xmin/hr60

units/hroutputdesired

sec./daytimeavailable)(sec./unittimeCycle

hourperpizzasorunits/hr,72sec./unit50

sec./hr.3600

timetaskbottleneck

timeavailableoutputMaximum


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Step 4: Compute the theoretical minimum number of

stations TM = number of stations needed to achieve 100%

efficiency (every second is used)

Always round up (no partial workstations) Serves as a lower bound for our analysis

stations3or2.75,

nsec/statio60

seconds165

timecycle

timestaskTM


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Step 5: Assign tasks to workstations

Start at the first station & choose the longest eligibletask following precedence relationships

Continue adding the longest eligible task that fits

without going over the desired cycle time

When no additional tasks can be added within the

desired cycle time, begin assigning tasks to the next

workstation until finished

Workstation Eligible task Task Selected Task time Idle time

A A 50 10

B B 5 5C C 25 35

D D 15 20

E, F, G G 15 5

E, F E 12 48

F F 10 38

H H 18 20

I I 15 5

1

2

3


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Step 6: Compute efficiency and balance delay

Efficiency (%) is the ratio of total productive timedivided by total time

Balance delay (%) is the amount by which the line

falls short of 100%

91.7%100sec.60xstations3

sec.165

NC

t(%)Efficiency

8.3%91.7%100%delayBalance


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Shape of the line (S, U, O, L):

Share resources, enhance communication & visibility,impact location of loading & unloading

Paced versus un-paced lines

Paced lines use an automatically enforced cycle time

Number of products produced

Single

Mixed-model lines


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One of the most popular hybrid layouts uses Group

Technology (GT) and a cellular layout GThas the advantage of bringing theefficiencies of a

product layout to aprocess layout environment


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Process Flows before the Use of GT Cells


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Process Flows after the Use of GT Cells


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Layout planning is organizationally important for an

efficient operations Marketing is affected by layout especially when

clients come to the site

Human resources is affected as layout impacts

people

Finance is involved as layout changes can be costly

endeavors

05 facilities layout

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