Lean Product Level
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Transcript of 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
9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT
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
9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT
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.
9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT
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
9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT
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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
9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT
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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6/9/04 -- 8 [ /
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
9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT
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
9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT
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.
9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT
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
9/04 --LFM Students] ESD.60 Lean Six Sigma Systems, LFM, MIT
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