chapter 15 all

8/10/2019 Chapter 15 All

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Slack, Chambers and Johnston, Operations Management 5thEdition Nigel Slack, Stuart Chambers, and Robert Johnston 2007

Chapter 15

Lean

operations

and JIT

Source: Tibbet and Britten


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Lean operations and JIT

Operations

strategy

Design Improvement

Planning and

control

Operations

management

Lean operations and JIT

The operation supplies the delivery of products andservices only when needed

The market requires specified time, quantity and

quality of products and

services


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The key principle of lean operationsis relatively

straightforward to understand: it means moving

towards the elimination of all waste in order to

develop an operation that is faster and more

dependable, produces higher quality products

and services and, above all, operates at low cost.


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Synonyms

continuous flow manufacture

high value-added manufacture

stockless production

low-inventory production

fast-throughput manufacturing

lean manufacturing

Toyota production system

short cycle time manufacturingSource: Corbis/Denis Balihouse


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Traditional approach

JIT approach

stage A

orders

deliveries

orders

deliveries

JIT material flow

buffer

inventorystage B

buffer

inventorystage

C

stage A stage Cstage B


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JIT

approach

focus on producing

only when needed

fewer stoppages

low inventory so

problems are

exposed and

solved

no surplus

production goes

into inventory

lower capacity

utilization, but

Traditional

approach

focus on high

capacity utilization

more stoppages

because of

problems

high inventory

means less chance

of problems being

exposed and solved

extra production

goes into inventory

because of continuing

stoppages at stages

more production

at each stage

JIT and capacity utilization


7/19Slack, Chambers and Johnston, Operations Management 5thEdition Nigel Slack, Stuart Chambers, and Robert Johnston 2007

JIT aims to meet demand instantly, with perfect quality and no waste

JIT definitions

More fully:

Improved overall productivity and elimination of waste

Cost-effective production and delivery of only the

necessary quantityof parts at the right quality, at

the right timeand place, while using a minimum

amount of facilities, equipment, materials and

human resources

JIT is dependent on the balance between the

suppliers flexibility and the users flexibility

JIT is accomplished through the application of

elements that require total employee involvementand teamwork

A key philosophy of JIT is simplification

Source: Empics



The lean philosophy of operations is the basis for JIT

techniques that include JIT methods of planning and control

The lean philosophy of operations

Eliminate waste Involve everyone Continuous

improvement

JIT as a set of techniques for managing

operationsBasic working practices

Design for manufacture

Operations focus

Small, simple machines

Flow layout

TPM

Set-up reduction

Total people involvement

Visibility

JIT supply

JIT as a method of

planning and control

Pull scheduling

Kanban control

Levelled scheduling

Mixed modelling

Synchronization



The 5 Ss

Sort (Seiri) Eliminate what is not needed and keep what is needed.

Straighten (Seiton) Position things in such a way that they can beeasily reached whenever they are needed.

Shine (Seiso) Keep things clean and tidy; no refuse or dirt in the workarea.

Standardize (Seiketsu) Maintain cleanliness and orderperpetualneatness.

Sustain (Shitsuke) Develop a commitment and pride in keeping tostandards.



Inventorylevel

Delivering smaller quantities more often can reduce

inventory levels

Inventory

level



operation

movement

inspection

storage

Activities:

Waste (muda) Which of these symbols signify non-value-adding activities?

influencing the throughput efficiency

Types of waste:

delay

over-production

waiting time

transport

process

inventory

motion

defective goods



WIP

Defective

materials

ReworkScrap

Downtime

productivity

problems

WIP

Defective

materials

ReworkScrap

Downtime

productivity

problems

Reduce the level

of inventory (water)

to reveal the

operations problems

The problem with inventory



Small machines

The conventional Western approach is to purchase large

machines to get economies of scale.

These often have long, complex set-ups, and make big

batches, quickly creating waste.



JIT small machines approach:

emphasis:flexibility

economies of scope

Using several small machines rather than one large one

allows simultaneous processing, is more robust

and is more flexible

easy to move (layout)

quick set-up

flexible scheduling options

cheaper tooling

fewer set-ups needed

planned maintenance easier


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complex

structures

simple

structures

JIT

MRP

JIT and/or

MRP

PERT

simple routings complex

routings

JIT, MRP, or both?


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Key Terms Test

Single minute exchange of dies (SMED)

Alternative term for set-up reduction.

AndonA light above a workstation that indicates its state: whetherworking, waiting for work, broken down, etc. Andon lightsmay be used to stop the whole line when one stationstops.


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th

Key Terms Test

Kanban

Japanese term for card or signal; it is a simple controllingdevice that is used to authorize the release of materialsin pull control systems such as those used in JIT.

Levelled scheduling (Heijunka)

The idea that the mix and volume of activity should evenout over time so as to make output routine and regular,sometimes known by the Japanese term heijunka.

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