chapter 11 lean synchronization -...

Slack, Brandon-Jones and Johnston, Essentials of Operations Management, 1st Edition, © Slack, Brandon-Jones and Johnston, 2011

Chapter 11

Lean synchronization


Slack et al’s model of operations management

Design

Deliver

Direct

Develop

Operations Management

Lean synchronis-

ation

Planning and control

Capacity manag-ement

Supply network

management

Inventory management


In Chapter 11 - Lean synchronisation – Slack et. al. identify the following key questions…….

What is lean synchronisation?

How does lean synchronisation eliminate waste?

How does lean synchronisation apply throughout the supply network?

Key operations questions


‘The key principle of lean operations is

relatively straightforward to understand, it means

moving towards the elimination of all waste in

order to develop an operation that is faster, more

dependable, produces higher quality products

and services and, above all, operates at low

cost’.

Lean operations


Synonyms

continuous flow manufacture

high value-added manufacture

stockless production

low-inventory production

fast-throughput manufacturing

lean manufacturing

Toyota production system

short cycle time manufacturing

Lean operations


Traditional approach:

JIT approach:

stage A

orders

deliveries

orders

deliveries

JIT material flow

buffer inventory

stage B

buffer inventory stage C

stage A stage Cstage B

Lean operations


Lean approach

focus on producing only when needed

lower capacity utilisation, but

no surplus production goes

into inventory

low inventory so problems are exposed and

solved

Traditional approach

focus on high capacity utilisation

more production at each stage

extra productiongoes into inventory

because of continuing stoppages at stages

high inventory means less chance of problems being

exposed and solved

Lean operations

more stoppages because of problems

fewer stoppages


InventoryOf material

(Queue of material)Of information

(Queue of information)Of customers

(Queue of people)Cost Ties up working capital Less current information

and so worth lessWastes customer’s time

Space Needs storage space Needs memory capacity Need waiting areaQuality Defects hidden, possible

damageDefects hidden, possible data corruption

Gives negative perception

Decoupling Makes stages independent

Makes stages independent Promotes job specialization / fragmentation

Utilization Stages kept busy by work in progress

Stages kept busy by work in data queues

Servers kept busy by waiting customers

Coordination Avoids need for synchronisation

Avoids need for straight through processing

Avoids having to match supply and demand

Source: Adapted from Fitzsimmons, J.A.

Inventories of materials. Information or customers have similar characteristics


‘Value stream’ mapping focuses on value-adding activities and distinguishes between value-adding and non-value-adding activities. It .is similar to process mapping but different in four ways:

It uses a broader range of information than most process maps.

It is usually at a higher level (5-10 activities) than most process maps.

It often has a wider scope, frequently spanning the whole supply chain.

It can be used to identify where to focus future improvement activities.

Value stream’ mapping


10

Waste is a large part of most processes

Actual value-add activity may only be 1 -10% of the total process time

High-level process steps

Prepareapplication

Acquire the customer

Processapplication

Advise customer

Disbursefunds

Activities which add value to the customer: e.g. the credit decision

Activities which don’t add value to the customer but are required by regulation: e.g. KYC

Activities which neither add value nor are required by regulation: e.g. carrying files from one desk to another

Step by step activity analysis for value-add to our customer

Mapping The Value Stream - ExampleHigh-level process steps for a loan application process


Value Stream Map for an industrial air conditioning installation service

T/T = Task timeTTT = Total throughput timeV-A T = Value-added timeC/T = Cycle time

Survey Order Assemble Frame

Wait in branch

Wait for assembly

Ship to branch and

wait

Wait for installers

Install

T/T = 0.5Avail = 100%C/T= 30

T/T = 0.5Avail = 100%C/T= 10

T/T = 5.0Avail = 100%C/T= 12.5

T/T = 0.75Avail = 100%C/T= 17

T/T = 0.75Avail = 100%C/T= 35

Cash management

Completion confirmation

Operations planning

Job tracking confirmations

Sales office

Forecasts Invoice status

30 mins.58 hrs.

30 mins.96 hrs.

5 hrs.48 hrs.

60 mins.48 hrs.

60 mins.

TTT = 258 hrs

V-AT = 8 hrs


Inventory levels

Delivering smaller quantities more often can reduce inventory levels

Inventory levels


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


WIPDefective materials

ReworkScrapDowntime

productivity problems

WIPDefective materials

ReworkScrapDowntime

productivity problems

Reduce the level of inventory (water) to reveal the operations’ problems

The problem with inventory


Small machines

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”.

Changeovers

Inventory levels

Time


Using several small machines rather than one large one allows simultaneous processing, is more robust and is more flexible.....

Small machines

Inventory levels

Time


Flow Principle

A process consists of 3 steps - A , B and C.It takes one minute to finish each step of the process. (A, B and C)

Batch Flow (units processed in batches of 10)

10 Minutes

How much time will it take for 10 units to move through the process?

A B C

10 Minutes 10 Minutes+ += 30 Minutes


Flow Principle

A process consists of 3 steps - A , B and C.It takes one minute to finish each step of the process. (A, B and C)Continuous Flow (unit processed individually, that is, process

one, move one)

1 Minute

How much time will it take for 10 units to move through the process?

1 Minute 10 Minutes+ + = 12 Minutes

A B C


Levelled scheduling equalizes the mix of products made each day

250 A

600 A 200 B200 C

Scheduling in large batches, where batch size A = 600, B = 200, C = 200

250 A

150 B

100 A

200 C

50 B

600A

200 B200 C

250 A

150 B 200 C

250 A 100 A 50 B

Over an eight day period, need to make............1200 of A

400 of B

400 of C

Every day, the schedule needs to be calculated. Each day can be different


Levelled scheduling equalizes the mix of products made each day

150 A50 B50 C

150 A

50 B

50 C

150 A50 B50 C

150 A

50 B

50 C

150 A50 B50 C

150 A

50 B

50 C

150 A50 B50 C

150 A

50 B

50 C

150 A50 B50 C

150 A

50 B

50 C

150 A50 B50 C

150 A

50 B

50 C

150 A50 B50 C

150 A

50 B

50 C

150 A50 B50 C

150 A

50 B

50 C

With levelled scheduling, where batch size A = 150, B = 50, C = 50

Over an eight day period, need to make............1200 of A

400 of B

400 of C

Every day is the same. Easy to notice if falling behind schedule

chapter 11 lean synchronization -...

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