Lean Product Level

7/29/2019 Lean Product Level

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Heijunka

Product & Production LevelingModule 9.3

Mark Graban, LFM Class of 99, Internal Lean Consultant, Honeywell

Presentation for:

Summer 2004

i

Amy Reyner, Kweku Fleming

ESD.60 Lean/Six Sigma Systems

MIT Leaders for Manufacturing Program (LFM)

These materials were developed as part of MIT's ESD.60 course on "Lean/Six Sigma Systems." In some cases,

the materials were produced by the lead instructor, Joel Cutcher-Gershenfeld, and in some cases by student teamsworking with LFM alumni/ae. Where the materials were developed by student teams, additional nputs from the

faculty and from the technical instructor, Chris Musso, are reflected in some of the text or in an appendix


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Overview

Learning Objectives Introduce and demonstrate

the concept ofHeijunka

Understand the benefits ofHeijunka

Understand how to applyHeijunka in a typicalmanufacturing process

Identify how Heijunkainteracts with other Leantools.

Session Design (20-30 min.) Part I: Introductions (1-2

min.)

Part II: Definition of Heijunkaand identification of its role inLean manufacturing. (3-5min.)

Part III: Study models ofHeijunka in use. Step

through an example ofHeijunka (7-13 min.)

Part IV: Benefits and Trade-offs associated with Heijunka& Common Disconnects, (57 min.)

Part V: Re-Cap andConcluding Comments (2-3min.)

9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT


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Heijunka

Key Concepts

thesis by Sean Hilbert

Heijunka is defined as The distribution of productionvolume and mix evenly over time

1

predictable manufacturing process

Heijunka is generally used in combination with other key Leanprinciples to stabilize value flow

manufacturing process

1


Adapted from MIT LFM

Heijunka converts uneven Customer Pull into even and

Heijunka is a core concept that helps bring stability to a

Lean Production Simplified, Pascal Dennis


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The Need for Heijunka

changeovers, but usually result in:

long lead times, swelli

mix

iA more level


There are a number of reasons for implementing Heijunka:

Product Levelinglarge batches of the same product may reduce set-up times and

ng inventories

greater opportunities for defects.

excessive idle time and/or overtime.

An even of products is critical to avoiding these impacts

Production LevelingRemember the Beer Game? Fluctuations n demand ( Boller or BullwhipEffect) are often highly amplified and delayed throughout the supply chain.

Responding to fluctuating customer demand can result in increased overtimeor idle time.

Variable production schedules can be stressful = Unhappy workers.

production volume eases these complications


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Supplier produces

4500 based on

demand.

Our workers begin torevolt due to

demanding and

unpredictable work.

Start taking long

lunches at Chotchskys

Supplier sees sharp

decline in demand.

so produces far less.

Supplier sees

increase in demand.

Excited to sell more

product, significantly

increases production

Supplier notices

demand. Lowers

of inventory.

Supplier goes out of

business due to inventory

and workforce management

costs. Workers for our

company quit to becomeconstruction workers.


last years avg.

Has extra inventory,

steady decrease in

production to get rid

Chasing Demand The Bullwhip Effect


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What is Production Leveling?

A Simple Example

17,316

16,866

16,326

44

4

=

=

=

4,217

4,329

4,082



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JIT vs. Production Leveling

given period of level production.

for short periods of higher demand*

Predictable work schedules

Supply Chain.

Meet customer demand upon

varying customer demand backupstreams

Bullwhip Effect


Meet customer demand in total over a

Finished Goods Inventory to make up

Stability transmitted to Supplier

Reduces Inventory over the entire

Overtime savings

Happy people Upstream

request (just in time)

Reduced Finished Goods Inventory

Unpredictable work schedules

High variability for Supplier Cascade

Overtime occasionally


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1 2 3 4 5 6 7 8

Week

Batching

Product Leveling

Customer waiting for

supplier.

What is Product Leveling?

Extended downtime formachine conversions.

ly.

flexibly tooled.

Customers are happy with

steady and predictable flow

happy with even work flow

We make As, Bs, and Cs: AA B C

LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT

product A is tired of

waiting. Goes to anotherWorkers go home ear

Conversion times are

reduced and machines areof product. Workers are


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Challenges for Heijunka

Technical Factors

Heijunka Leveling are often

With Heijunka, there is a needfor larger Finished GoodsInventory. This can be seen asantithetical to Lean mission.

Can not immediately be

predictable environment,

customer data. Predicting demand is

imperfect.process.

Social Factors

Heijunka depends on Directinformation about projected

(future) events.

Explaining why its importantto do standardized work

Reduces operator flexibilitywhich can draw resistance

Requires discipline and muchmore planning


Tools needed for large-scale

lacking.

Obsolescence of finished parts

implemented requires

Bad data can ruin

customer contact and accurate

before implementing HJ.


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Concluding Comments

IfTakt time is described as the heart beatof Lean implementation,then Heijunka is the deep breathing exercise of Lean that brings

internal and external suppliers.

Heijunka, You wont be HAPPY without it!2

2


stability (calm) to the manufacturing process, spreading it upstream to

The Toyota Production System: Leaner Manufacturing for a Greener Planet. Published 1998,


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Appendix: Instructors Comments and Class

Discussion for 9.3

Heijunka reveals the limits of the label lean and points to aknowledge-driven process for ensuring stability, flow and pull

Consider the level at which Heijunka expertise needs to be Most lean operations strike a balance between product leveling

and production leveling

really is some balance between the two

Heijunka requires a lot of data, and can be tough to deal with Heijunka is not necessarily useful for businesses with level and

dependable demand.


It is still about ensuring the customer has what they want, when

they want it at the price they are willing to pay

established plant-wide, departments, individual work areas?

Good not to have inventory, good to meet demand, but there

Worker happiness is an important measure of heijunka success


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Appendix: Instructors Guide

2-3 min9

You wont be happy without Heijunka

1-2 min01

unfinished inventories

2-4 min8

inventory.

It is

i

ing

4-7

3

1-2Slide

Key Concepts3-5 min

Distributing

time.

learning objectives

2-3 minAdditional Talking PointsTopicTime


Imperfect Data, Large Safety Inventory, Increased

Planning Required,

Challenges for Heijunka

Heijunka is the Deep Breathing Exercise for the

Manufacturing Process

Conclusion

Product Leveling: Long Lead times, large

Heijunka Product leveling seeks to break down

batches into smaller interspersed runs

What is Product Leveling?

Heijunka levels production, JIT results in level

Safety stock is a key to Heijunka.

Heijunka is not implemented in a vacuum.

effective when ntegrated with other lean tools,

reduced set-ups, Takt time, Kanban planning etc.

The Need for Heijunka

What is Production Leveling?

JIT vs. Heijunka Level

7-13 min

Heijunka converts uneven customer pull into

predictable value flow. Converts inefficientbatching processes into coordinated multi-tasking

Heijunka is Production Leveling

production volume or production mix evenly over

Introduction, overview and

Documents

Lean Product Level