SMED

Quick Changeover

Set-up and Changeover Reductions for Equipment, Tooling and Machines

Jack E. Abbruzzese P.Eng. (jack.abbruzzese@djg.ca)

Process Engineer, DJ Galvanizing Corporation.

Windsor-Essex Chapter PEO Lean Concepts Subcommittee

The goal is to reduce and/or eliminate downtime

due to setups and changeovers

Machine

Running

Machine

RunningMachine Stopped

Internal setup External setupExternal setup

Total Set up

What is SMED? Driven by the need to change over a process to produce

a product in the most efficient manner. Reducing Setup (or Change Over) is the technique allowing the mixing of production/products without slowing output or creating higher costs associated with non-value adding activity (NVAA). Changeovers add no value and therefore should be minimized.

Quick Changeover, also known as SMED (Single-Minute Exchange of Die) is a proven technique originally developed and refined over a period of 19 years of applications at Toyota by Mr. Shigeo Shingo. Systematic use of this technique has enabled that company to achieve a phenomenal reduction in all product changeovers on their production lines. Currently 85% of all of their changeovers are <100 seconds (OTED or One-Touch Exchange of Die), another 14% are <10 minutes (SMED), and only 1% take 10 minutes or longer!

Single Minutes Exchange of Dies

History

Valuable References Related to

SMED System: Ohno, Taiichi (1988), The Toyota Production System:

Beyond Large-Scale Production, Productivity Press, Portland, Oregon.

Shingo, Shigeo (1985), A Revolution in Manufacturing: The SMED System, Productivity Press, Inc., Portland, Oregon.

Shingo, Shigeo (1989), A Study of the Toyota Production System from an Industrial Engineering Viewpoint, Productivity Press, Portland, Oregon.

Shingo, Shigeo (1996), Quick Changeover for Operators: The SMED System, Productivity Press, Inc., Portland, Oregon.

SMED and EOQ Single Minute Exchange of Dies

More precisely, single digit minute exchange of dies –changing dies in under 10 minutes.

Tied to Economic Order Quantity or LOT SIZE. Balance of inventory costs versus downtime for

changeover.

Economic Order Quantity is the lot size where:

Cost associated with

inventory

(interest, storage

costs)

Cost associated with

Changing over

(downtime, retooling

costs)

Development Optimization of Lot Size.

High lot size reduces overhead costs due to changeover but…

Increases inventory, interest and storage costs.

Automotive industry sought to optimize the lot size by looking at changeover times. Toyota had an additional motivator.

Toyota optimization Space limitations and high added cost to inventory for leasing

storage drove Toyota engineers to look at changeover in earnest to greatly reduce inventory costs.

By greatly improving changeover, lot sizes dropped dramatically, almost making EOQ irrelevant.

Also, reduced finished goods lot size meant stock levels of material goods also dropped, further reducing costs.

TPS Development Over several years, Toyota reworked factory fixtures and

vehicle components to make common parts, minimize assembly, standardize the steps, all contributing to reduced changeover. Where tooling could not be made common, changeover was minimized.

The stamping dies presented the biggest challenges due to the sheer size of equipment.

By analyzing the then current practices, Toyota systematically and scientifically reduced changeover from days and hours down to hours and ultimately minutes. The EOQ was reduced to LESS THAN 1 vehicle!

Lean Manufacturing Model

Goal of Lean

CONTINUOUS IMPROVEMENT

Guiding principles to continually make

improvement in Quality, pace, and cost.

Better, Faster, Cheaper.

This reduces time between customer order

and shipment of finished product by

eliminating waste in all areas. Customer

Order

Shipment of

Finished ProductContinuous

Improvement

How Quick Changeover Fits in

Reduce non-productive change-over time.

Every minute stopped counts as waste.

Coordinates with implementation of cellular

manufacturing and progress to continuous

modelling.

Once operations formed into cells, transitions and

changeovers must be reduced and personnel trained

in the optimal changeover practices.

How Quick Changeover Fits in

What is Quick Changeover? SMED – Single Minute Exchange of Dies

Stop Machine and Empty the Dirt! (ABB example for general product transition improvement).

RETAD – Rapid Exchange of Tools and Dies

OTED – One Touch Exchange of Dies (< 100 seconds).

NOTED – NO Touch Exchange of Dies

Elimination of transition waste.

Changeover

can involve

fouling.

STOP

ResumeClean -

changeover

Why Quick Changeover

Promotion of One Piece Flow

Reduction of WIP levels

Reduction of downtime

Reduction of Inventory

Increase flexibility

Simplify the process – make more repeatable

Benefits

Reduced tangible and intangible costs related with setup time, inventory, space, materials, and customer delivery. Reduced defect rates by promoting quality from the first piece.

Adjustments for setup reduced.

Reduced inventory costs – smaller batches, lot sizes. JIT and stockless production possible through quick changeover.

Goods not lost due to deterioration.

Improved on-time delivery. Meet customer demands.

Increased production flexibility. Shorten time to customer, increase production. Simplified housekeeping.

Simpler system, better safety.

And MORE…

Quick Changeover Improvement

Technique - Process Establish the current changeover time.

Identify each task to accomplish changeover

Identify tasks that can be ELIMINATED

Determine EXTERNAL AND INTERNAL TASKS

ELIMINATE all unnecessary tasks

EXTERNALIZE all tasks identified as External This means these tasks are DONE while machine is running or in service.

STREAMLINE all internal tasks. This means optimization of the select tasks that MUST be done when the

machine is stopped.

ESTABLISH New Changeover Time.

It doesn’t end here… REPEAT the process on other applications.

Return to this application and optimize again.

See it, solve it, do it, done!

What’s next?

Lather, Rinse, Repeat.

Quick Changeover Improvement Technique

– External and Internal tasks EXTERNALIZE all tasks identified as External

This means these tasks are DONE while machine is running or in service.

Make sure you are not WAITING for these tasks to complete while machine is stopped!

Examples, Securing a crane for lifts, forklift availability, clearing floor-space, spare die at machine ready for insertion.

STREAMLINE all internal tasks. This means optimization of the select tasks that MUST be done when the

machine is stopped.

Some tasks or events CANNOT happen with the machine running. Examine each one for opportunity for improvement to shorten the down-time to a minimum.

MachineRunning

MachineRunning

Machine Stopped

Internal setup External setupExternal setup

Total Set up

Quick Changeover Improvement

Technique - Specifics Form Cells – Cellular manufacturing.

Combine dies.

Rotate dies.

Redesign dies for rapid changes, various techniques.

Gage blocking and precision gaging for dies, ensure setup repeatable.

Sequence the change to utilize associated equipment efficiently (cranes etc)

Convert to continuous process model Welders, rollers, conveyors, logical stitching of components so pieces

flow through from one operation to another.

Shuttle and rail exchange systems

Automatic scheduling and preset control

Application

Racing Teams – 10 second pit stop!

Stamping dies – classic example.

Deposition systems, rapid clean and

changeover to various deposit media.

Rolling, forming, cutting equipment.

Examples – Racing Team

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Quick Changeover Enablers:

Single lug wheels.

Precision fuel additions.

Sequenced tire changes.

Defined roles.

And now….

Athletic PIT CREW!

Examples – Stamping Dies

Carts

Conveyors

Rails,

Airfloat system for

large dies

Examples – Shuttle coater - DJG

Coater

Shuttle provision for

online offline

movement and

coater A, coater B

(future) placement

Examples – Trimmers, Slitters

Tooling – close to

equipment!

Trimmer, Slitter

exchange rail and

transfer car.

Taylor Steel, tri-axle

quick change slitter

(left).

DJG trimmer, slitter

exchange rail and

transfer car. (right)

Examples – Temper Mill (SPM)

Steel sheet runs through

line continuously. Rail

and cart system facilitate

QUICK CHANGE of work

rolls with minimal product

loss (<200m steel).

Examples – CGL Oiler

Oiler replaced with latest technology, Dec 2009 improved control – Saves MONEY!

Purge (oil changeover) time reduced from 60 s to 30 s. New system purges faster and with less cross-contamination, improving defects and reducing rework!

Examples – CGL Furnace

Anneal code models and setpoint control via weld point tracking allow for transitions of furnace temperature as the product is running, maintaining quality and eliminating changeover times! Scheduling

Anneal code smoothing

Speed control

Furnace controls

QUICK CHANGEOVER

One more ingredient in the Lean

Transformation Arsenal.

It’s all about

CONTINUOUS

IMPROVEMENTPhoto courtesy of Taylor Guitars

www.taylorguitars.com