Lean Manufacturing & Just-in-Time

"The most dangerous kind of waste is the waste we do not recognize." -

Shigeo Shingo

Material Flow

Information Flow

FGI

CustomerRaw

MaterialSupplier

FinalAssembly

PUSH

FGI

CustomerRaw

MaterialSupplier

FinalAssembly

PULL

Reducing Waste: Push versus Pull System

Push System Every worker maximizes own output, making as

many products as possible Pros and cons:

Focuses on keeping individual operators and workstations busy rather than efficient use of materials

Volumes of defective work may be produced Throughput time will increase as work-in-process

increases (Little’s Law) Line bottlenecks and inventories of unfinished products

will occur Hard to respond to special orders and order changes due

to long throughput time

Pull System Production line is controlled by the last

operation, Kanban cards control WIP Pros and cons

Controls maximum WIP and eliminates WIP accumulating at bottlenecks

Keeps materials busy, not operators. Operators work only when there is a signal to produce.

If a problem arises, there is no slack in the system Throughput time and WIP are decreased, faster

reaction to defects and less opportunity to create defects

5

• Management philosophy• “Pull” system though the plant

WHAT IT IS

• Employee participation• Industrial engineering/basics• Continuing improvement• Total quality control• Small lot sizes

WHAT IT REQUIRES

• Attacks waste• Exposes problems and bottlenecks• Achieves streamlined production

WHAT IT DOES

• Stable environment

WHAT IT ASSUMES

Features of Lean Production

Kaizen

A Little History! Ford: Design for manufacturing

Start with an article that suits and then study to find some way of eliminating the entirely useless parts. This applies to everything— a shoe, a dress, a house, a piece of machinery, a railroad, a steamship, an airplane. As we cut out useless parts and simplify necessary ones, we also cut down the cost of making. ...But also it is to be remembered that all the parts are designed so that they can be most easily made."

A Little History!

Ohno – put ideas into practice systematically “When bombarded with questions from our group on

what inspired his thinking, Ohno just laughed and said he learned it all from Henry Ford's book."

A system that continually searches for and eliminates waste throughout the value chain.

Views every enterprise activity as an operation and applies its waste reduction concepts to each activity - from Customers to the Board of Directors to Support Staff to Production Plants to Suppliers.

TPS: Toyota Production System

Elimination of Waste

Complexity

Labor

Overproduction

Space

Energy

Defects

Muda

Materials Inventory Time Transportation

Acronym – CLOSED MITT

10

1. 5S

2. Group technology

3. Quality at the source

4. JIT production

5. Kanban production control system

6. Minimized setup times

7. Uniform plant loading

8. Focused factory networks

Elimination of Waste

Minimizing Waste – 5S“Good factories develop beginning with the 5S’s. Bad factories fall apart beginning with the 5 S’s.”

- Hirouki Hirano

Japanese Translation English

Seiri Proper arrangement Sort

Seiton Orderliness Simplify

Seiso Cleanliness Sweep

Seiketsu Cleanup Standardize

Shitsuke Discipline Sustain

Minimizing Waste – 5S

A place for everything and everything in its place Not just a housekeeping issue Critical foundation for

Setup reduction Pull systems Maintenance Inventory management

Using Departmental Specialization (Job Shop) for plant layout can cause a lot of unnecessary material movement

Using Departmental Specialization (Job Shop) for plant layout can cause a lot of unnecessary material movement

Saw Saw

Lathe PressPress

Grinder

LatheLathe

Saw

Press

Heat Treat

Grinder

Note how the flow lines are going back and forthNote how the flow lines are going back and forth

Minimizing Waste: Group Technology

Press

Lathe

Grinder

Grinder

A

2

BSaw

Heat Treat

LatheSaw Lathe

PressLathe

1

Revising by using Group Technology Cells can reduce movement and improve product flow

Revising by using Group Technology Cells can reduce movement and improve product flow

Minimizing Waste: Group Technology

Minimizing Waste: JIT Only produce what’s needed The opposite of “Just In Case” philosophy Ideal lot size is one Minimize transit time Frequent small deliveries

Pro’s

•Minimal inventory

•Less space

•More visual

•Easier to spot quality issues

Con’s

•Requires discipline

•Requires good problem solving

•Suppliers or warehouses must be close

•Requires high quality

???

16

Inventory Hides Problems

Work inprocess queues(banks)

Changeorders

Engineering designredundancies

Vendordelinquencies

Scrap

Designbacklogs

Machine downtime

Decisionbacklogs

Inspectionbacklogs

Paperworkbacklog

Minimizing Waste: JIT

Minimizing Waste – Quality at the Source “Do it right the first time” Call for help Immediately stop the process and correct it vs.

passing it on to inspection or repair

Andon

Jidoka

Minimizing Waste – Kanban

Signaling device to control flow of material

•Cards

•Empty containers

•Lights

•Colored golf balls

•Etc

Minimizing Waste – Setup Times

Long setup times drive: Long production runs Large lots Long lead times

JIT requires small lots and minimum kanbans Setup reduction

Focused efforts Problem solving Flexible equipment

21

Not uniform Jan. Units Feb. Units Mar. Units Total

1,200 3,500 4,300 9,000

Uniform Jan. Units Feb. Units Mar. Units Total

3,000 3,000 3,000 9,000

Suppose we operate a production plant that produces a single product. The schedule of production for this product could be accomplished using either of the two plant loading schedules below.

Suppose we operate a production plant that produces a single product. The schedule of production for this product could be accomplished using either of the two plant loading schedules below.

How does the uniform loading help save labor costs?How does the uniform loading help save labor costs?

or

Minimizing Waste – Plant LoadingHeijunka

CoordinationSystem Integration

These are small specialized plants that limit the range of products produced (sometimes only one type of product for an entire facility)

These are small specialized plants that limit the range of products produced (sometimes only one type of product for an entire facility)

Minimizing Waste – Focused Factory Networks

Level payrolls

Cooperative employee unions

Subcontractor networks

Bottom-up management style

Quality circles (Small Group Problem Solving)

TPS – Respect for People

Keiretsu

1. All work shall be highly specified as to content, sequence, timing, and outcome

2. Every customer-supplier connection must be direct, and there must be an unambiguous yes-or-no way to send requests and receive responses

3. The pathway for every product and service must be simple and direct

4. Any improvement must be made in accordance with the scientific method, under the guidance of a teacher, at the lowest possible level in the organization

TPS – 4 Rules

Lean Implementation

Empowered WorkforceProblem Solving

Performance Measurement

Total QualityManagement

FlowProcess

StableSchedule

KanbanPull

InvolvedSuppliers

Continual InventoryReduction

ProductDesign

Summary and Conclusions… Lean Production is the set of activities that achieves

quality production at minimum cost and inventory The flow of material is pulled through the process by

downstream operations Lean originated with the Toyota Production System

and its two philosophies – elimination of waste, and respect for people

CLOSED MITT forms of waste