Lean Manufacturing - An Overview

Dr. Richard A. Wyskrwysk@psu.edu

http://www.engr.psu.edu/cim

Fall 2008

Broad Agenda

• Overview of Lean Manufacturing– Lean according to R. Wysk Set-up reduction and rapid

response production systems

– Changing in order to change more quickly

• Case Study– Lean at home in the kitchen

• Some models and discussions– Learning/forgetting

– 6 sigma in rapid response systems

Agenda

• Review brief history of manufacturing systems• Distinguish between mass, craft and lean

manufacturing• Introduce key Concepts of

Lean Manufacturing • Review the kinds of changes needed to be

considered a lean manufacturer.

Readings

• Chapter 18 of Computer Aided Manufacturing, Wang, H.P., Chang, T.C. and Wysk, R. A., 4th Edition (2008 expected)

http://www.engr.psu.edu/cim/ie550/ie550lean.pdf

Objectives

• To identify waste elements in a system• To apply value stream analysis to a

complex engineering/manufacturing system

• To implement 3 M’s in a complex engineering environment

• To be able to identify and implement the 5Ss of lean

Craft Manufacturing • Late 1800’s• Car built on blocks in the barn as workers walked

around the car.• Built by craftsmen with pride• Components hand-crafted, hand-fitted• Good quality• Very expensive• Few produced

Mass Manufacturing • Assembly line - Henry Ford 1920s

• Low skilled labor, simplistic jobs, no pride in work

• Interchangeable parts

• Lower quality

• Affordably priced for the average family

• Billions produced - identical

Lean Manufacturing

• Cells or flexible assembly lines• Broader jobs, highly skilled

workers, proud of product• Interchangeable parts,

even more variety• Excellent quality mandatory• Costs being decreased through

process improvements.• Global markets and competition.

Definition of “Lean”

• Half the hours of human effort in the factory

• Half the defects in the finished product

• One-third the hours of engineering effort

• Half the factory space for the same output

• A tenth or less of in-process inventories

Source: The Machine that Changed the World Womack, Jones, Roos 1990

Materials Labor Equipment Energy Methods Products

Lean Manufacturing is a manufacturing philosophy which shortens the time line between the

customer order and the product shipment by eliminating waste.

CustomerOrder

Waste ProductShipment

Time

CustomerOrder

ProductShipment

Time (Shorter)

Business as Usual

Waste

Lean Manufacturing

11

The Nature of Lean Mfg

• What Lean Mfg is not– JIT– Kanban– Six sigma

• Characteristics– Fundamental change– Resources– Continuous improvement

• Defined– “A system which exists for the production of goods or

services, without wasting resources.”

IntroductionIn 1926 Henry Ford wrote

– “To standardize a method is to choose out of the many methods the best one, and use it. Standardization means nothing unless it means standardizing upward.

Today’s standardization, instead of being a barricade against improvement, is the necessary foundation on which tomorrow’s improvement will be based.

If you think of “standardization” as the best that you know today, but which is to be improved tomorrow - you get somewhere. But if you think of standards as confining, then progress stops.”

Kaizen vs Reengineering• Creating an useable and meaningful standard is key to the

success of any enterprise.• Businesses usually utilize two different kinds of improvements.

– Those that suppose a revolution in the way of working.– Those that suppose smaller benefits with less investment.

Kaizen

Final situation

Initial situation

time

Reengineering

productivity

Kaizen vs Reengineering

• The evolution consists of continuous improvements being made in both the product and process.

• A rapid and radical change (kaikaku) process is sometimes used as a precursor to kaizen activities.

– Carried out by the utilization of process reengineering or a major product redesign.

– Require large investments and are based on process automation.

• In the U.S., these radical activities are frequently called “kaizen blitzes”.

Kaizen vs Reengineering• If the process is constantly being improved (continuous line), the

innovation effort required to make a major change can be reduced (discontinuous line in the left).

– Otherwise, the process of reengineering can become very expensive (discontinuous line in the right).

Kaizen

Final situation

Initial situation

time

Reengineering

productivity

What makes a manufacturing system lean? – the 3 M’s of lean

• muda – waste• mura - inconsistency • muri - unreasonableness

What makes a manufacturing system Lean?

18

Definitions

• Systems– Recognition

– Efficiencies

• Waste– Muda

– 7 types

– Truly lean

Waste

“Anything that adds Cost

to the product

without adding Value”

“Anything that adds Cost

to the product

without adding Value”

20

7 Types of Muda

• Excess (or early) production• Delays• Transportation (to/from processes)• Inventory• Inspection• Defects or correction• Process inefficiencies and other non-value added

movement (within processes)

7 Forms of Waste

Typesof

Waste

CORRECTION

WAITING

PROCESSING

MOTION

INVENTORYCONVEYANCE

OVERPRODUCTION

Repair orRework Any wasted motion

to pick up parts or stack parts. Also wasted walking

Wasted effort to transportmaterials, parts, or finished goods into or out of storage, or between processes.

Producing morethan is needed before it is needed

Maintaining excessinventory of raw mat’ls,parts in process, orfinished goods.

Doing more work thanis necessary

Any non-work timewaiting for tools, supplies, parts, etc..

Let’s use lean for something we know about – cooking for a party

Excess /Over-production –As applied to fast food preparation

• ________________

• ________________

• ________________

• ________________

• ________________

• ________________

Waiting/Delays

• __________

• __________

• __________

• __________

• __________

• __________

Transportation/Movement

• _________

• _________

• _________

• _________

Layout efficiency

Inventory

• _________

• _________

• _________

• _________

Inspection

• __________________

• __________________

• __________________

• ______________

• ______________

• ______________

Corrections and defects• ____________

• ____________

• ____________

• ____________

• ____________

Processing inefficiencies

• __________________

• __________________

• __________________

• __________________

Processing inefficiencies

• Automatics vs. manual

Over-Processing inefficiencies• Two people

doing some thing that one could do

• Workplace layout– Congestion– Labeling

• Automatics vs. manual

Over-Processing inefficiencies

• Material waste

Manufacturing inefficiencies

• Processes (value added)– Inefficient process selection– Inefficient process operation– Too much direct labor

• Delays– Schedules– Blocking– Congestion

• Quality– Any defects– Rework

• Set-up– Setting up a machine instead of running it– Accumulation of tooling and other processing needs

Machining example

• CNC versus manual– Tool changer– Pallet changer/bar feeder

How do CAD/CAM systems work?

• Developing NC code requires an understanding of:

1. Part geometry

2. Tooling

3. Process plans

4. Tolerances

5. Fixturing

• Most CAD/CAM systems provide access to:

1. Part geometry

2. Tooling

Instructions can be generated for a generic NC machine

•A set of tool paths and positions can be automatically generated

•These paths can be edited and modified

•These paths and instructions can then be “posted” to a specific machine

The Design Process : Then and Now

Before CAD After CAD

Exercise (3-5 minutes)

• Discuss how CAD/CAM helps in Lean Manufacturing? Elaborate on any one aspect.

• What advantages does CAD/CAM approach offer in NC Programming?

CAD/CAM Support

• AutoCAD

• Pro Engineer

• Solidworks

• MasterCAM

What do I need to begin MasterCAM?

• Part geometry– Draw or import

• Tooling– Library or create

• Process plans

• Fixtures– Define orientation and location

Who wants what...

CustomerLow CostHigh QualityAvailability

Your CompanyProfitRepeat BusinessGrowth

Cash !!Cash !!$

Value !!Value !!

43

Elements of Lean Manufacturing

• Waste reduction

• Continuous flow

• Customer pull

• 50, 25, 25 (80,10,10) Percent gains

44

Benefits of Lean Manufacturing

• 50 - 80% Waste reduction– WIP– Inventory– Space– Personnel– Product lead times– Travel– Quality, costs, delivery

45

Setting the Foundation

• Evaluating your organization– Management culture

– Manufacturing culture

• Lean Manufacturing Analysis– Value stream (from customer prospective)

– Headcount

– WIP

– Inventory

– Capacity, new business, supply chain

46

Tools of Lean Mfg/Production• Waste reduction

– Full involvement, training, learning– Cellular mfg– Flexible mfg– Kaikaku (radical change)– Kaizen (continuous improvement) & standard

work– 5S– Jidoka (autonomation)– Poka-yoke (visual signals)– Shojinka (dynamic optimization of # of

workers)– Teien systems (worker suggestions)– Six sigma

47

Tools (cont.)

• Continuous Flow (10% - 25%)– SMED (Shingo)

– Andon

– Takt time

– Line balancing

– Nagara (smooth production flow)

48

Tools (cont.)

• Customer pull (10%- 25%)– Just-in-time– Kanban

Standardized Work

• Captures best practices• Posted at the work station• Visual aid• Reference document

– work sequence– job layout– time elements– safety

• Developed with operators• Basis for Continuous Improvement

Other Tools

• Visual Factory

• Error Proofing

• Quick Change-over

• Total Productive

Maintenance

51

5S Programs

• Seiri (sort, necessary items)

• Seiton (set-in-order, efficient placement)

• Seison (sweep, cleanliness)

• Seiketsu (standardize, cont. improvement)

• Shitsuke (sustain, discipline)

• “Ability to understand the status of a production area in 5 minutes or less by simple observation without use of computers or speaking to anyone.”

• 5-S– 1S Sift and Sort (Organize)– 2S Stabilize (Orderliness)– 3S Shine (Cleanliness)– 4S Standardize (Adherence)– 5S Sustain (Self-discipline)

Visual Factory

Price Increase

Some ProfitSome ProfitBigger ProfitBigger Profit

Price to Sell

Price to Sell

Cost to ProduceCost to

Produce 1

2

3

1

2

3

Cost + Profit = PriceCost + Profit = Price

Cost Reduction

Some ProfitSome Profit

Bigger ProfitBigger Profit

Price to Sell

Price to Sell

Cost to ProduceCost to

Produce

1

2

3

1

2

3

Price - Cost = ProfitPrice - Cost = Profit

What value is

Added by:

What value is

Added by:

SortingCounting

AcknowledgmentsMoving

Expediting

Inspecting

Returns to Suppliers

Repackaging

Scrap

Storing

Invoices

Rework

Loading / Unloading

Receiving Report

Toyota Production SystemBest Quality - Lowest Cost - Shortest Lead Time

Through shortening the Production Flow by Eliminating Waste

Just in Time“The right part

at the right timein the right amount”

• Continuous Flow• Pull System• Level Production (Heijunka)

Jidoka“Built in Quality”

• Manual / Automatic Line Stop• Labor-Machine Efficiency• Error Proofing• Visual Control

Flexible, Capable,Highly Motivated

People

Standardized WorkTotal Productive Maintenance

Robust Products & ProcessesSupplier Involvement

Operational Stability

Very Frequent Change-over

8 hours

change over

Right Hand

change over

Left Hand

change over

Right Hand

change over

Left Hand Left Hand

change over

Right Hand

change over

Left Hand

change over

Right Hand

change over

Left Hand

change over

Right Hand

change over

Left Hand

change over

Right Hand

change over

Building in Quality

Machinesintelligence to be self-operating and

self-stopping

People served by machines, not vice versa

Quality built-in, not inspected-in

Efficiency human work separated from machine

work, people freed to do value-added

work

JIDOKA

Quality as part complexity increases

Number of features P{Good Part} P{Good Part}

3 sigma 4 sigma1 99.73% 99.98%

10 97.33% 99.83%

100 76.31% 98.31%

1000 6.69% 84.36%

P{good part} = [P{good dimension and good location}]# of features

Planning for Quality

• Plan for control limits well outside process variability

• Monitor the process; not the product

• Make sure that process/procedures do not go out of control

Error Proofing

• Preventing accidental errors in the manufacturing process

– Error detection– Error prevention

• A way to achieve zero defects.

Performance barriersArrivals 60 minutes between parts Service 55 minutes/part

Performance barriers (con’t)

Arrivals Service Wait in system Constant Constant 0 minutes

Random (Poisson) Constant 300 minutes

Random (Poisson) Random (Poisson) 600 minutes

End - Waste Elimination

Questions?