JIT and LeanOperations

McGraw-Hill/Irwin Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved.

You should be able to:1. Explain what is meant by the term lean operations

system2. List each of the goals of a lean system and explain its

importance3. List and briefly describe the building blocks of lean4. List the benefits of a lean system5. Outline the considerations important in converting a

traditional mode of operations to a lean system6. Point out some of the obstacles that might be

encountered when converting to a lean system7. Describe value stream mapping

Student Slides 14-2

Lean operationA flexible system of operation that uses

considerably less resources than a traditional systemTend to achieve

Greater productivityLower costsShorter cycle timesHigher quality

Student Slides 14-3

The ultimate goal:Achieve a system that matches supply to

customer demand in a smooth uninterrupted flow

A balanced systemOne that achieves a smooth, rapid flow of materials

and/or work through the system

14-4Student Slides

Student Slides 14-5

The lean’s ultimate goal is achieved by its supporting goals:1. Eliminate disruptions2. Make the system flexible3. Eliminate waste, especially excess inventory

Student Slides 14-6

Product designProcess designPersonnel/organizational elementsManufacturing planning and control

Student Slides 14-7

Five personnel/organizational elements important to lean systems:Workers as assetsCross-trained workersContinuous improvementCost accountingLeadership/project management

Student Slides 14-8

Seven elements of manufacturing planning and control (MPC) are particularly important for lean system:1. Level loading2. Pull systems3. Visual systems4. Limited work-in-process (WIP)5. Close vendor relationships6. Reduced transaction processing7. Preventive maintenance and housekeeping

14-9Student Slides

Push systemWork is pushed to the next station as it is

completedPull system

A workstation pulls output from the preceding workstation as it is needed

Output of the final operation is pulled by customer demand or the master schedule

Pull systems are not appropriate for all operationsLarge variations in volume, product mix, or product

design will undermine the system

14-10Student Slides

Kanban Card or other device that communicates demand

for work or materials from the preceding stationKanban is the Japanese word meaning “signal” or

“visible record”

Paperless production control systemAuthority to pull, or produce, comes

from a downstream process.Two main types of kanbans:

1.Production kanban (p-kanban): signals the need to produce parts

2.Conveyance kanban (c-kanban): signals the need to deliver parts to the next work center.

14-11Student Slides

Ideal number of kanban cards

part theof usagedaily percentof 10than more no be (shouldcontainer standard a ofCapacity

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parts ofcontainer afor timeproduction averageplus parts ofent replenishmfor time waitingAverage

center work using of rate usage planned

container)per card (1 containers ofnumber Total

where

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14-12Student Slides

1. Make sure top management is committed and that they know what will be required

2. Decide which parts will need the most effort to convert

3. Obtain support and cooperation of workers

4. Begin by trying to reduce setup times while maintaining the current system

5. Gradually convert operations, begin at the end and work backwards

6. Convert suppliers to JIT

7. Prepare for obstacles

14-13Student Slides

1. Management may not be fully committed or willing to devote the necessary resources to conversion

2. Workers/management may not be cooperative

3. It can be difficult to change the organizational culture to one consistent with the lean philosophy

4. Suppliers may resist

Student Slides 14-14

Be careful to study the requirements and benefits of lean systems before making a decision to convert operations Evaluate strengths and weaknesses of current

operations

The decision to convert can be sequentialWeigh the pros and cons of a lean approach to

inventoriesSupplier management is critical to a lean

operation

Student Slides 14-15