Lean Manufacturing

Why Lean is the key to improved manufacturing

What is Lean?

• Fundamental objective:– To create the most value while consuming the

fewest resources.

How is the objective accomplished?

Lean production is aimed at the elimination of waste in every area of production including customer relations, product design, supplier networks and factory management. Its goal is to incorporate less human effort, less inventory, less time to develop products, and less space to become highly responsive to customer demand while producing top quality products in the most efficient and economical manner possible.

Cycle Time“ One of the most noteworthy accomplishments in

keeping the price of Ford products low is the gradual shortening of the production cycle. The longer an article is in the process of manufacture and the more it is moved about, the greater is its ultimate cost.”

Henry Ford, 1926

• Lean Production• Eiji Toyoda visits Ford’s Rouge plant in 1950 and

returns to Japan to discuss his study with his production engineer, Taiichi Ohno.

• Mass production techniques are determined to be inappropriate for Japan because:1. The market in Japan demanded a large variety

of different vehicles in relatively small quantities.

2. Unlike the practice in America, treating the workforce as a variable cost was not possible in Japan. Management’s right to lay off employees was severely restricted.

3. The Japanese economy was starved for capital after the war, so purchasing the latest, expensive equipment was not an option.

History of Lean Manufacturing

Source: The Machine That Changed The World, Womack, Jones, and Roos, p. 44.

Intro to Lean Mfg

Steps to Create a Lean Entreprise

1. Specify value in the eyes of the customer 2. Identify the value stream and eliminate

waste 3. Use a pull system that is triggered by the

customer 4. Involve and empower employees 5. Continuously improve in the pursuit of

perfection (from “Lean Thinking” by Womack and Jones)

Lean is customer focused

• Make what the customer wants, when the customer wants it, at a price the customer is willing to pay

Value stream mapping

• Follow a “product” or “service” from beginning to end

• Draw a visual representation of every process in the material & information flow

Value Stream MappingHelps us see where value is created, and where waste

exists:

• A visual approach, by “product family”

• Shows flow of both material & information

• Helps us see which specific Lean tools can be used to improve flow and eliminate waste

• Two maps will be made: Present State (“how it is”) & Future State (“how it should be”)

• Will guide the creation of an action plan to make the “should be” into a reality for that product family

Value stream map

Definition of Value-Added

Value-Added• Any activity that increases the market form or function

of the product or service. (These are things the customer is willing to pay for.)

Non-Value Added (Waste or muda)• Any activity or use of resources that does not add

market form or function or is not necessary. (These activities should be reduced, integrated, simplified, or eliminated.)

Using the Value Stream Map to Eliminate Waste

• Complexity• Labor• Overproduction• Space• Energy• Defects

• Materials• Idle Materials•Transportation•Time

Non-Value-Added: Hold all waste in a “CLOSED MITT”Value-Added

Typically 95% of all lead time is non-value-added

ComplexityThe waste of doing things the hard way!

• Excessive paperwork

• Excessive approvals

• Redundancy

Causes of complexity:

• Multiple “patches” on the process w/o fixing the root cause.

• The “cool” factor of technology or machinery.

• Failing to look for the simple solutions.

Labor Waste• Human effort that adds no value to the product or

service from the customers’ viewpoint.

• Not using people’s mental, creative, and physical abilities

• Causes of labor waste– Poor people/machine interface

– Inconsistent work methods

– Unfavorable workstation or cell layout

– Doing unnecessary/unneeded operations

– Poor workplace organization and housekeeping

– Redundant inspections/approvals

– Extra copies/excessive information

OverproductionThe waste of making too much, too soon, too

fast compared to the needs of the next process.

• Causes of overproduction– Just-in-case logic

– Misuse of automation

– Long process setup

– Non-level scheduling

– Unbalanced workload

– Misunderstood communications

– Reward system

– Unreliable shipment by suppliers

Space Waste

• Using more space than is required to build the product to market demand.

• Causes of wasted space– Poor layout

– Too much inventory, especially work in process

– Poor workplace organization

– Excess equipment

– Oversized equipment

Energy Waste

• Using more energy (people and machine) than is required to build the product to market demand.

• Causes of wasted energy– Oversized or poorly maintained equipment

– Idle equipment

– Poor workplace organization

Defects• Waste of inspection, repair and scrapping of

material to which value has already been added.

• Causes of defects– Weak process control

– Poor quality system

– Deficient planned maintenance

– Inadequate education/training/work instructions

– Product design

– Customer needs not understood

– Defective information

Materials WasteAny use of materials in excess of what

is needed to create value.

• Causes of material waste– Not understanding the costs

– Inadequate education/training/work instructions

– Lack of standards

– Customer needs not understood

Idle MaterialsThe waste of having materials “sitting around”

in process without any value being added to them.

• Causes of idle materials waste

– Unbalanced workload

– Unplanned maintenance

– Long process setup times

– Poor suppliers

– Upstream quality problems

– Unlevel scheduling

Transportation Waste

• Transporting parts and materials around the plant, stacking and un-stacking, etc.

• Causes of transportation waste

– Poor plant layout

– Poor understanding of production process flow

– Large batch size, long lead

times, large storage areas

Time WasteAny activity that consumes time without

adding value, especially the waste of waiting (equipment downtime, waiting for materials, setup, etc.).

• Causes of wasted time:• Poor machine maintenance.

• Line imbalances.

• Poor setup discipline.

• Poor communication between processes.

Lean Building Blocks

Quick Changeover

Standardized Work

Batch Reduction

Teams

Quality at Source

5S System VisualPlant Layout

POUS

Cellular/Flow

Pull/Kanban TPM

ValueStreamMapping

Continuous Improvement

Definition for Kaizen ― Alternate name for Lean

• Kaizen: leadership philosophy, a management methodology, and a set of tools all wrapped into one.– Indicates long-term betterment– Makes “little improvements”– Under Kaizen, the entire facility is orderly – Visual keys are used to assist in ordering

the workplace

Visual Controls• Simple signals that provide an immediate

understanding of a situation or condition. They are efficient, self-regulating, and worker-managed.

• Examples:

– Kanban (stock signal) Cards

– Color-coded dies, tools, pallets

– Lines on the floor to delineate storage areas, walkways, work areas etc.

– Lights to indicate production status

– Location signs on shop floor and in the office

– Identification labels everywhere

Standardized WorkGraphic = Good

• Tools are illustrated

• Parts are pictured and numbered

• Spatial relationships are clearly shown

• Small items enlarged to show assembly detail

• All items are either physically labeled or identified by number in assembly graphic

Standardized Work

5S - Workplace Organization A safe, clean, neat, arrangement of the workplace

provides a specific location for everything, and

eliminates anything not required.

In Lean manufacturing, we refer to this as 5S.

Examples: EMT’s, fire department, etc.

Elements of a 5S Program• Sort—Perform “Sort Through and Sort Out,” - red tag all

unneeded items and move them out to an established “quarantine” area for disposition within a predetermined time. “When in doubt, move it out!”

• Set in Order—Identify the best location for remaining items and label them. “A place for everything & everything in its place”.

• Sweep (Systematic Cleaning)—Clean everything, inside and out. Use visual sweeps to ensure everything is where it should be and that junk is not accumulating.

• Standardize—Create the rules for maintaining and controlling the first 3 S’s. Use visual controls.

• Sustain—Ensure adherence to the 5S standards through communication, training, self-discipline and rewards.

Before 5S

Before 5S

After 5S

After 5S

After 5S

Traditional Plant Layout

Plant Layout for Flow

Raw Stock QC Rec Ship

Shear

Screw Machin

e

QCStam

p

AssemblyBrak

eMill

Lathe

Weld FinishGrind Parts Stock

Drill

Obstacles to Flow• “Monuments”:

– Unmovable items in the plant, i.e., large pieces of equipment, structural supports or walls, etc.

– Too expensive to move or replace, yet not in the proper place to allow good product flow.

• What do we do about monuments?

– We have to leave them where they are (for now)!

– We do our best to work around them.

– Put in place the best flow given the monuments, but must always be looking for a better way.

Impact of Batch Size Reduction

10 minutes

10 minutes

Batch & Queue Processing

Lead Time

30+ minutes for total order21+ minutes for first piece

10 minutes

ProcessA

ProcessB

ProcessC

ProcessB

ProcessA

ProcessC

Continuous Flow Processing

12 min. for total order3 min. for first part

The Ideal Lot Size• Ideal lot size is one• Velocity = The smaller the lot

size, the faster the parts will flow through the manufacturing process

• Flexibility = The smaller the lot size, the more variety in demand the system can handle

More Lean Tools

• Setup Reduction or Quick Changeover (SMED)

• Point of Use Storage (POUS)

• Quality at the Source

• Visual Inspection

• Pull (including Kanban, Two Bin, Min/Max)

• Cellular Manufacturing

• Total Productive Maintenance

Change Over

• STEPS IN A CHANGEOVER:

1. Preparation

2. Remove/Install Tooling

3. Change Machine Settings

4. Make Trial Pieces & Adjust

Setup Reduction or Quick Changeover

• Definition: Minimizing the time from last good piece of the current product run to first good piece of the next (different) product run.

Percent of time of changeover

Making trial pieces and adjusting

50%15%

30%

15%5%

Preparation, after-process adjustment, checking, return to storage of parts, tools, fixtures, move materialsRemoving parts, blades, jigs, etc.; mounting same for next lot, move materialsMachine settings, measurements

Change Over

• Reduce the complexity and increase the efficiency of setups by standardizing as much of the hardware and methodology as possible.

No/Low Cost Solution: Use of Positioning Pins

Positioning Pins

Positioning Pins

No/Low Cost Solution: One-Turn Methods

Pear-Shaped Hole Method

Tighten Here

Attach and

Remove Here

Other Functional Clamps

Quick Changeover: Visual Controls

Quick Changeover

Clearly labeled cutter size and style

All regular router cuts needed in this workcell stored at router table.

Standardization & Setup Reduction

•Common fasteners and fittings – standardize on the sizes and types.

•Standardized carrier plates, fixtures, shut heights, etc.

•Standardized procedures along “product families”, where the product families share common manufacturing processes & equipment.

•Share information and communicate “best practices” across all operations and shifts.

•Monitor & track setup times relative to standard time.

Point of Use Storage (POUS)

• Raw material, components used, and information is present at workstation where used

• Works best if vendor relationship permits frequent, on-time replenishment and small shipments

• Simplifies physical inventory tracking, storage, and handling

Quality at the Source

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

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

• 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 workstation needs to be developed.

Visual Inspection Example

•No missing screws

•All screws seated

•Specify what to inspect

•Clear inspection criteria

•Don’t overload operator with complex content or criteria

Push vs. Pull Systems

• Push System

– Resources are provided to the consumer based on forecasts or schedules

• Pull System

– A method of controlling the flow of resources by replacing only what has been consumed

Pull System

• Pull system consists of:– Production based on actual consumption

– Small lots

– Low inventories

– Management by sight

– Better communication

Pull System Flow DiagramInformation Flow

Supplier

RawMatl

ProcessA

ProcessB

Fin. Goods

Kanban Locations

ProcessC

Customer

Parts Flow

Pull System Methods• Kanban:

– A visual signal telling us what we need to produce.

– Cards, “open spots”, etc.

• Two-bin System:

– Used for commonly produced items, sub-assemblies.

– When a bin is empty, fill it.

– Ensures there is always material available while minimizing inventory.

• Supermarket or ‘Grocery Store’ System:

– Controlled & limited “shelf” space.

– Replenish items to the shelf as needed.

Cellular Manufacturing

Linking of manual and machine operations into the most efficient combination to maximize value-added content while minimizing waste.

Punch

Cut to sizeDe-burr

Sand

FormPackage

Advantages of cells: Communication and shared labor

Moving to Cellular Manufacturing/Flow Production

Inv Inv

Inv

Inv

C

DE

BInvA

A

InvA

AInv

A

Inv

Inv

Inv

InvB

B

Inv InvB Inv

C

C

C

C

Inv

Inv Inv Inv Inv

E

E

E

D

D

DD

Dept “A” Dept “B” Dept “C”

Dept “E”Dept “D”

DE

C

BA

DE

C

BA

Stage 1Production in Specialized Departments

Stage 2Production in Product Cell

Stage 4Production in Compact Cell with One-Piece Flow

and Separation Man/Machine

Stage 3Production in Compact Cell with One-Piece Flow

Total Productive Maintenance (TPM)• Systematic approach to the elimination of

equipment downtime as a waste factor

• Enlisting the intelligence and skills of the people who are MOST familiar with the factory machines: the equipment operators

• Charting/analyzing equipment performance to identify root cause of problems, and implementing permanent corrective actions

Continuous Improvement (CI)

Old Adage:

“If you always do what you always did, you’ll always get what you always got.”

Competitive Corollary:

“If the other guy gets BETTER, you’re gonna get LESS.”

Lean Workforce Practices• Teams

– With identified goals and measured performance

– With rotation of highly specified jobs

• Cross-trained and multi-skilled employees

– Who can work many operations within a cell and operations in different cells

• Continuous improvement philosophy

• Process quality, not inspection

• Use of participatory decision-making processes

– Gap analysis, team-based problem solving, project management, etc.

Implementation Success Factors• Unyielding leadership

• Strategic vision based on Lean enterprise as part of company strategy

• Observe outside successes and failures

• Ability to question EVERYTHING

• Deep commitment to EXCELLENCE

• Consistency

• Clear channels of communication

Comparison of Traditional vs. LeanLean

• Simple and Visual

• Demand Driven

• Inventory as Needed

• Reduce Non-Value-Added

• Small Lot Size

• Minimal Lead Time

• Quality Built-in

• Value Stream Managers

Traditional• Complex

• Forecast Driven

• Excessive Inventory

• Speed Up Value-Added Work

• Large Batch Production

• Long Lead Time

• Quality Inspected-in

• Functional Departments

Must Not Must

Go to theShop Floor

Think of atleast 7 ways to do better

Kaizen yourStandard Work

Have a vision

Observe the process Find the Waste

Provide the right tools

Set goals

Communicate direction

Hide in the office

Create smoke screens Grovel Be clueless

Throw fits

Give up

Blame the worker

Blame the Measure

Tamper with the MeasureCover up

Stress out Throw People at Problems

FlexMuscles

Show BoatEmpower the Team

Celebrate Success

Lead by ExampleIntimidate

Quality of a GOOD Leader

Mapping the Future State• Determine Available Time/Demand• Determine where continuous flow is possible• Determine what pull systems will be used• Determine pacemaker operation• Determine how pacemaker will be

scheduled/leveled• Determine increment of work released at

pacemaker• Identify necessary process improvements to

achieve future state flow

Future State Value Stream Map

Results

• Production lead time 23.5 days 4.5 daysOld New

Thank You.

L E A NE N T E R P R I S E

Places to look for waste

• Over-production

• Waiting time

• Transportation

• Processing

• Inventory

• Motion

• Scrap

Setup Time Drives Batch Size:The Economic Order Quantities (EOQ) model determines the most economic lot/batch size for a production run.

Fixed Cost

Increasing Lot/Batch Size

EOQ

Changeover Cost

Inventory Carrying Cost

Changeover Cost + Inventory Carrying Cost

Variable

Cost