Lean Manufacturing Principles

www.ies.ncsu.edu/lean

LEAN LEAN MANUFACTURING MANUFACTURING

PRINCIPLESPRINCIPLES

© NCSU IES LEAP Group Rev 3/04


The ConnectionThe Connection

North Carolina State University Teaching, Research, Extension and Engagement

College of Engineering

Industrial Extension Service (IES)

North Carolina State University Teaching, Research, Extension and Engagement

College of Engineering

Industrial Extension Service (IES)


Industrial Extension ServiceIndustrial Extension Service Lean Enterprise Advancement Program (LEAP)

In-plant applications, manufacturing networks, public training, Shingo Prize

Advanced Performance and Standards (APS) FORUMS, QS, ISO, Six Sigma, Project management,

NC Awards for Excellence

Environmental, Health and Safety (EHS) Training, technical assistance, needs assessment in

ISO, HAZWOPER, HAZMAT, ergonomics and industrial hygiene

Energy and Facilities Management Energy usage assessments

Lean Enterprise Advancement Program (LEAP) In-plant applications, manufacturing networks, public

training, Shingo Prize

Advanced Performance and Standards (APS) FORUMS, QS, ISO, Six Sigma, Project management,

NC Awards for Excellence

Environmental, Health and Safety (EHS) Training, technical assistance, needs assessment in

ISO, HAZWOPER, HAZMAT, ergonomics and industrial hygiene

Energy and Facilities Management Energy usage assessments


Lean Enterprise Advancement ProgramLean Enterprise Advancement Program

Mission -

Improve the quality, cost and delivery of North Carolina manufacturing firms to improve their competitiveness by understanding and implementing lean enterprise business systems based on TPS model.


The LEAP mission is accomplished through -

training

facilitation

manufacturing networks

lean assessments


LEAN THINKING

VALUE - what customers are willing to pay for

VALUE STREAM - the steps that deliver value

FLOW - organizing the Value Stream to be continuous

PULL - responding to downstream customer demand

PERFECTION - relentless continuous improvement

(culture)

--- Lean Thinking, Womack and Jones, 1996

Key Principles of Lean Thinking


Defining LeanDefining Lean

“A systematic approach to identifying and eliminating

waste (non-value added activities) through continuous

improvement by flowing the product at the pull of the

customer in pursuit of perfection.”

The MEP Lean Network

Lean is:


Lean Goals- TPS “True North”Lean Goals- TPS “True North”

Zero defects

100% value-add

Lot size of one

Pull of the customer

Zero defects

100% value-add

Lot size of one

Pull of the customer

TSSC


LEAN MANUFACTURINGLEAN MANUFACTURINGWhy Become Lean?

•PQCDSM•Improve Customer Satisfaction•Increase Sales and Profits•Insure Long-term Health of Company•Survival•Create Sustainable Competitive Advantage


Typical Results from Lean Conversions

Lead Time ReductionLead Time Reduction

Productivity IncreaseProductivity Increase

WIP ReductionWIP Reduction

Quality ImprovementQuality Improvement

Space UtilizationSpace Utilization

00 2525 5050 7575 100100Percentage of Benefits AchievedPercentage of Benefits Achieved

FlexibilityFlexibility Skill EnhancementSkill Enhancement Visual ManagementVisual Management


LEAN MANUFACTURINGLEAN MANUFACTURINGWhere has Lean been successfully implemented?

•ManufacturingAutomotiveIndustrial ProductsFurniture Textiles and ApparelPrinting and PackagingConsumer Products

•Service Industries•Military•Healthcare


Developing a Lean FactoryDeveloping a Lean Factory

The Goal and Getting There from Here

•The Goal - Lean Throughout the Entire Enterprise•Set Aggressive Improvement Goals•Measurements of Existing Operations•Recognize Current Problem Areas•Apply the Lean Production System Concepts•Commit to the Continuous Improvement Process

•Just do it!


Value Added/Non-value Added Value-added:

ANY ACTIVITY THAT PHYSICALLY CHANGES THE MATERIAL BEING WORKED ON (not rework/repair!)

Machining Knitting

Drilling Spreading/Cutting

Assembly Dying

Painting Sewing

Non-value added:

ANY ACTIVITY THAT TAKES TIME, MATERIAL, OR SPACE BUT DOES NOT PHYSICALLY CHANGE THE MATERIAL

Sorting Stacking

Counting Checking


8 Wastes Overproduction Excess

inventory Defects Non-value

added processing

Waiting Underutilized

people Excess motion Transportation

Lean = Eliminating the waste

Typically 95% of Total Lead Time is Non-Value Added!!!

Value added

5%

Non-value added


Value Stream MappingValue Stream Mapping

A simple diagram of every step involved in the material and information flows needed to bring a product from order to delivery.

Value stream maps can be drawn for different points in time as a way to raise consciousness of opportunities for improvement.

- Lean Lexicon


- Learning to See


Lean Production System Goals - highest quality, lowest cost, shortest lead times

Heijunka Standardized Work Kaizen

Just-In-Time•continuous flow•takt time/pace

•pull system•triggers

Jidoka•separate man &

machine work•identify abnormal

conditions•poka yoke

Stable Manufacturing Process

Involvement


Toyota’s Philosophy

• Customer first

• People are the most valuable resource

• Kaizen (continuous improvement)

• Shop floor focus


Goals - highest quality, lowest cost, shortest lead times








Involvement

Lean Production System


StabilityStabilityThe Four Ms

Operations safely carried out with all task organized in the best known sequence and by using the most effective combination of resources

•huMans•Materials•Methods•Machines


StabilityStabilityThe 5S’s

•Sort•Keep only what is needed in your area

•Stabilize•A place for everything and everything in its place

•Shine•Clean up the workplace

•Standardize•Develop system (rules) to maintain what has been done

•Sustain•Self discipline to maintain established procedures


The 5S’s - Before

StabilityStability


StabilityStabilityThe 5S’s


StabilityStability

Courtesy of National Textiles

The 5S’s


StabilityStabilityVisual Controls

Visual Controls are simple signals that provide an immediate understanding of a situation or condition. They are efficient, self regulating, and worker managed. Examples include:

• Pictures, diagrams • Color coded dies, tools, pallets• Lines on the floor to delineate storage areas, walk ways, work areas, etc.• Improved lighting


StabilityStabilityVisual Controls


StabilityStabilityPlant Layout

Raw StockQ C Receivin

g

Shipping

ShearScrew

MachineQ C

Stamp

AssemblyBrake Mill

Lathe

Weld FinishGrind Parts Stock

Drill


Cellular Layout

Market Demand = 220,000 Units Per YearMarket Demand = 220,000 Units Per YearTakt Time = 27 SecondsTakt Time = 27 Seconds

LatheLathe MillMill MillMill InspectInspectDrillDrill

DrillDrill

TestTestDrillDrillPackPack

11 22 33 44 55

1010 99 88 77

66

27 27 SecondsSeconds


InspectInspect


StabilityStability


StabilityStabilityCellular Layout

Courtesy of Duff-Norton, Charlotte, NC


StabilityStabilityTotal Productive Maintenance

Total Productive Maintenance (TPM) is a series of methods to keep equipment running

The goals of the TPM process include:•Develop people who are equipment-knowledgeable•Create well-engineered equipment: building in safety and quality•Create an environment where enthusiasm and creativity flourish•Maximize equipment productivity and capacity as measured by Overall Equipment Effectiveness (OEE)


Related Losses

• Setup and Adjustment

• Breakdowns

Related Losses

• Idling and Minor Stoppages

• Reduced Speed

Related Losses

• Startup

• Defects and Rework

OEE = Availability × Performance Efficiency × Rate of Quality

Availability

When or how often do you lose total availability of your equipment?

How long are your set-ups?

Does your equipment break down frequently?

Performance Efficiency

Does your equipment start and stop a lot?

Does your equipment run at 100% of its designed speed?

Rate of Quality

Do you manufacture quality products?

Are your processes repeatable?

StabilityStability

The Six Big Losses that downgrade Machine Effectiveness:


Sample Daily Operator PMDaily Operator PM

1. Check coolant level through clear Plexiglas

2.Check heat exchanger fans(strings should be moving)

3.Check servo drive fans (string should be moving)

4.Check heat exchanger air filter(change when dark)

5.Check servo drive air filter(change when dark)

6.Check way lube reservoir(add when low)

7.Check main motor air filter(change when dark)

8.Check main motor cooling fan(string should move)

9.Check mist collector motor and air filter(change when dark)

10.Check bar feeder hydraulic motor air filter

11.Check bar feeder hydraulic oil level(add when low)


Developing a Lean FactoryDeveloping a Lean FactorySummary – Stability in Manufacturing

Processes

•4Ms•5S•Visual Controls•Plant Layout•Total Productive Maintenance










Involvement


Just-in-TimeJust-in-TimePull System

•Pull System is a flexible and simple method of controlling/balancing the flow of resources.

– Eliminating waste of handling, storage, expediting, obsolescence, repair, rework, facilities, equipment, excess inventory (work-in-process and finished).

•Pull System consists of:– Production based on actual consumption– Small Lots– Low inventories– Management by Sight– Better Communication



• Kanban

- A signal to indicate when more parts are needed(Order or Produce)

- Card, empty Bin, In Process Kanban (IPK) on plant floor



Courtesy of Ingersoll-Rand Co., Southern Pines, NC


Just-in-TimeJust-in-Time

• A carton of milk is removed from shelf

•A stock person restocks the empty location, but only brings what shelf can accommodate

•the supermarket combines visual control, pull system, Kanban, 5S

Supermarket Analogy


Just-in-TimeJust-in-TimeQuick Changeover (Set-up Reduction)

Single Minute Exchange of Dies (SMED)•a series of techniques for changeovers of production machinery in less than ten minutes (single digit minutes)

Set-up Reduction Program Goals•To achieve smaller lots•To maintain consistent quality•To minimize inventory•To reduce lead times•To address frustration of setup personnel


Identify internal vs. external

changeover tasks

Analyze each task’s real

purpose and function

Focus on no/low cost

solutions

Aim to eliminate

changeover time

Just-in-TimeJust-in-TimeBasic SMED Principles



Positioning Pins

Positioning Pins


No/Low Cost Solution: One-Turn Methods

Pear-Shaped Hole Method

Tighten Here

Attach and Remove

Here




Speed Nut




Wing Nut Method



No/Low Cost Solution: One-Motion Methods

Cam Method



Just-in-TimeJust-in-TimeQuick Changeover

Not quick: Must heat molds and plates before changeover

Quicker: Test stand with hot plates to pre-heat molds and plates

Courtesy of Playtex Panama, Santo Domingo, DR


Just-in-TimeJust-in-TimeContinuous Flow - Batch Size Reduction

•The best batch size is one - one piece flow, or make one and move one!

•Benefits: Reduces WIP, lead time, cycle time, etc. and improves quality


10 minutes

10 minutes

• Batch & Queue Processing

Lead Time: 30+ minutes for total order21+ minutes for first piece

10 minutes

ProcessA

ProcessB

ProcessC

12 min. for total order3 min. for first part

ProcessB

ProcessA

ProcessC

• Continuous Flow Processing



Takt Time = Demand RateTakt Time = Demand Rate

WorkWork Time AvailableTime AvailableNumber of Units SoldNumber of Units Sold

Takt TimeTakt Time = =

GOAL: Produce to Demand



Developing a Lean FactoryDeveloping a Lean Factory

Summary - Just-in-Time

•Pull Systems/Kanban•Point Of Use Storage•Quick Changeover/Setup Reduction•Continuous Flow•Takt Time










Involvement


JidokaJidokaQuality at the Source

•Source Inspection: Operators must be certain that the product they are passing to the next work station is of acceptable quality.

•Operators must be given the means to perform inspection at the source, before they pass it along.


JidokaJidokaQuality at the Source

Courtesy Sara Lee Intimate Apparel, Villanueva, Honduras

Source Inspection at Molding


JidokaJidoka


“Bull’s Eye” for checking package size


JidokaJidoka

Quality at the Source

•Samples or established standards are visible tools that can be used in the cell for such purposes

•Process Documentation defining quality inspection requirements for each work station may need to be developed


JidokaJidoka

Poka-Yoke (Mistake Proofing)

A Poka-yoke device is any mechanism that either prevents a mistake from being made or makes the mistake obvious at a glance.

Poka-yoke devices:- perform well when corrective action involves trying to eliminate oversights and omissions.- can reduce the time and cost of informative inspection to near zero.- used with source inspection, can ensure that proper operating conditions exist prior to actual production.


JidokaJidokaPoka-Yoke (Mistake Proofing)

Examples: Fueling area of car has three mistake-proofing devices:

1.filling pipe insert keeps larger, leaded-fuel nozzle from being inserted 2.gas cap tether does not allow the motorist to drive off without the cap 3.gas cap is fitted with ratchet to signal proper tightness and prevent over-tightening.


JidokaJidokaPoka-Yoke (Mistake Proofing)


JidokaJidokaAndon

A visual management tool that highlights the status of operations in an area

at a single glance and that signals whenever an abnormality occurs.

An andon can indicate production status (for example, which machines are

operating), an abnormality (for example, machine downtime, a quality

problem, tooling faults, operator delays, and material shortages), and needed

actions, such as changeovers. An andon can also be used to display the status

of production in terms of the number of units planned versus actual output.

--- The Lean Lexicon


JidokaJidokaAndon

Courtesy of Sara Lee Intimate Apparel


“When I was asked to attend the general manager’s meeting the first time, I was happy to attend because I thought I could say that there were no problems in my department. And I said so when it was my turnto report. Then, this General Manager from Toyota looked straight intomy eyes and said, ‘Steve, when you say you do not have a problem, thatis the problem.’”

At this moment, I realized that in order to succeed in this business, I have to change my way of thinking totally.

--- From JIT Kakumei no Shogeki by Kiyoshi Suzaki, p. 14.

JidokaJidokaIdentifying Problems


JidokaJidokaIdentifying Problems - Trystorming


Before After


JidokaJidoka


Developing a Lean FactoryDeveloping a Lean FactorySummary - Jidoka

•Quality at the Source•Poka Yoke•Andons•Effective Problem Solving










Involvement


StandardizationStandardizationStandardized Work

Establishing precise procedures for each operator’s work in a production process, based on three elements:

1. Takt time, which is the rate at which products must be made in a process in order to meet customer demand.

2. The precise work sequence, in which an operator performs tasks within takt time.

3. The standard inventory, including units in machines, required to keep the process operating smoothly.

--- The Lean Lexicon


StandardizationStandardization


StandardizationStandardizationStandard Work Board

Courtesy of Ingersoll-Rand Co., Southern Pines, NC


Takt Time = 10 seconds



Leveling the type and quantity of

production over a fixed period of

time. This enables production to

efficiently meet customer demands

while avoiding batching and

results in minimum inventories,

capital costs, manpower, and

production lead time through the

whole value stream.

Leveling the type and quantity of

production over a fixed period of

time. This enables production to

efficiently meet customer demands

while avoiding batching and

results in minimum inventories,

capital costs, manpower, and

production lead time through the

whole value stream.

StandardizationStandardizationHeijunka

---The Lean Lexicon


A tool used to level the mix and volume of production by distributing kanban within a facility at fixed intervals. Also called a leveling box.

A load-leveling box has a column of kanban slots for each pitch interval, and a row of kanban slots for each product type.

StandardizationStandardizationHeijunka Box

---Learning to See


The practice of releasing production instructions to work areas and withdrawing completed product from work areas at a fixed, frequent pace.

In this type of handling system, a material handler, or waterstrider, performs a route through a facility at precisely determined time intervals.

StandardizationStandardizationPaced Withdrawal

---Learning to See



Courtesy of Duff-Norton, Charlotte, NC


The location where a predetermined standard inventory is kept to supply downstream processes.

Supermarkets are ordinarily located near the supplying process to help that process see customer usage and requirements.

StandardizationStandardizationSupermarket

---Learning to See


Supermarket Pull System

Courtesy of Seamless Textiles, Humacao, PR



Kaizen

Continuous improvement of an entire value stream or an individual process to create more value with less waste.

There are two levels of kaizen (Rother and Shook 1999, p.8):1. System or flow kaizen focusing on the overall

value stream (kaizen for management).2. Process kaizen focusing on individual processes

(kaizen for work teams and team leaders).

- Lean Lexicon



Developing a Lean FactoryDeveloping a Lean FactorySummary - Standardization

•Standardized Work•Heijunka/Leveling•Paced Withdrawal•Supermarket•Kaizen










Involvement


InvolvementInvolvementWorkplace Practices

•Teams–with rotation of highly specified jobs.

•Cross trained and multi-skilled employees–who can work many operations within a cell and even operations in different cells

•Continuous improvement philosophy•Process quality, not inspection•Use of participatory decision making

–Quality Control Circles, team-based problem solving, suggestion systems, etc.


Keys To SuccessKeys To Success

Focus on the goal- eliminate waste!

Gather baseline information and

measure results

Get everyone involved

Keep it simple

Focus on the goal- eliminate waste!

Gather baseline information and

measure results

Get everyone involved

Keep it simple


Reference Materials

• Lean Thinking by Jim Womack and Daniel Jones

• Lean Production Simplified by Pascal Dennis

• Learning to See, Mike Rother, John Shook, The Lean Enterprise Institute, Inc, 1998.

• “Decoding the DNA of the Toyota Production System” by Stephen Spear and H. Kent Bowen, Harvard Business Review, September-October 1999, pp. 96-106


Lean Enterprise Advancement Program (LEAP)
