Equipment Efficiency: Availability, Q uality and SMED

1

Equipment Efficiency:Availability, Quality

and SMEDOperations Analysis and Improvement

2010 Fall

Dr. Tai-Yue WangIndustrial and Information Management Department

National Cheng Kung University

2Dr. Tai-Yue Wang IIM Dept. NCKU

Presentation

It has become increasingly important to economically manufacture products in smaller product batches. Product lead times must be kept as small as

possible. Product customization continues to increase.

Number of parts produced on manufacturing systems continues to increase

Batch sizes have been reduced.


Presentation Companies should be as agile and flexible as

possible. Reduce machine set-up time times to minutes instead

of days or hours. The Single-Minute Exchange of Dies (SMED) is

a clear easy-to-apply methodology. Good results in many cases very quickly. It was developed by Shigeo Shingo in Japan from

1950-80s. Achieve good results without costly investments.


Introduction

Set-up process. Time required to go from the end of the last good part

from one batch to when the first good part of the following batch is produced.

The trials needed to obtain the first good product are considered part of the set-up process.


Introduction SMED -> Single-Minute Exchange of Die.

Designed so that the set-up process should be made in less than 10 minutes.

During the 1960s the set-up time for a large stamping press could take more than a full day.

It is possible to achieve reductions around 60% of the original set-up time.

In reductions of about 90% the project costs become significant.

It is not always necessary to reduce the machine set-up process. Tires on your personal vehicle vs. car racing.


Introduction SMED is contemplated in the

Just-in-time and in the 20 keys methodologies (key number 5).

SMED improves the availability rate as well as the quality rate. This set-up time includes the trial

phase. Startup losses included in the quality

rate are produced in this trial phase

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SMED


Basic steps in a set-up process

Four typical classes of set-up operations regardless the type of the machine or equipment. Prepare, adjust and check (new materials and tools). Remove old tooling and install new tooling on the

machine. Measure, set and calibrate (fixtures, tools and tooling). Produce initial parts (production trials) and adjust the

machine..


Basic steps in a set-up process

Prepare, adjust and check operations focus on making sure that the tools and materials that will be used for set-up are available when the set-up is scheduled.

Produce initial parts and adjust depends on the set-up specialist’s know-how.


Traditional strategies

For high volume manufacturing applications, the set-up process duration was not particularly important. Manufactures could afford to have customers waiting. Production was scheduled based on manufacturing needs.

These set-ups hardly affected the product’s price. Shutdown production facility to for two weeks while machines and tools

were set-up for new model year production.

Today, manufacturing lot sizes have decreased. Manufacturing flexibility needs to increase.

Same quantity -> increased part variety and with smaller delivery quantities.


Traditional strategies

The possible production of defective parts at set-up coupled with the increased frequency of set-up has forced manufacturers to make more products than required.

In order to reduce set-up process affects, companies usually use two different strategies. Try to make the set-up as fast as possible. Increase the production lot size.


Skilled based strategies

Many companies have used set-up specialists to reduce changeover and set-up times. Skilled in the operation of specific

machines. Familiar with the needed tools and

methods to carry out the exchange.


Skilled based strategies

Dependence on these specialists can be strong. Skill that a set-up specialist needs. Set-up process complexity.

Not all the tasks that set-up specialists carry out are critical. The specialist can get help from the

machine operator.


Large batches based strategies The larger the batch size is, the smaller the impact of the set-up

time will be on the production cost of each part. Cost per part is based on the company cost system.

The system shares all company costs to each product. There is a section that depends on the time to manufacture and also on its

respective set-up time.

If the lot size is large, the set-up time effect is spread out more than if the lot size is small.

Batch size set-up time Production timeProduct manufacturing time

(including part of set-up time)

50 240 min. 2 min. 2 + 240/50 = 6,8

500 240 min. 2 min. 2 + 240/500 = 2,48

5.000 240 min. 2 min. 2 + 240/5.000 = 2,048

size batchtime up set

time production part singleTM


Large batches based strategies

The higher the set-up time, the bigger the profit will be.

This reasoning supports the lot size increasing. Some companies only accept orders that exceed certain

lot sizes.

Batch size set-up timeProduction

timeProduct manufacturing time


50 360 min. 2 min. 2 + 360/50 = 9,2

500 360 min. 2 min. 2 + 360/500 = 2,72

5.000 360 min. 2 min. 2 + 360/5.000 = 2,072


Large batches based strategies

If set-up time and production time were about the same magnitude…

… it would not make sense to search for large lots size.

Batch size set-up timeProduction

timeProduct manufacturing time


50 10 min. 2 min. 2 + 10/50 = 2,2

500 10 min. 2 min. 2 + 10/500 = 2,02

5.000 10 min. 2 min. 2 + 10/5.000 = 2,002


Economic Lot Size strategy

Large set-up times -> large batch size. Increase in inventory cost and potential loss for

products becoming obsolete. The economic lot size is a direct relationship

between the inventory cost and the set-up cost. The effect of the set-up cost decreases exponentially

according to the increase of the batch size. This hypothesis is based on a constant set-up time.


Economic Lot Size strategy As set-up cost decreases, the economic lot size would

also decrease until reaching the unit product lot size.

It would be profitable to only accept orders made up of one article – a batch size of one!

Batch size

set-upcosts


SMED methodology

1950 in Toyo Kogyo factory. Shingo discovered that the exchange of an 800 ton

press was delayed because of a missing screw. Two types of operations in the process of change.

Those that should be carried out with the machine running producing parts from the previous lot.

Shingo called these activities External set-up. Those that required the machine and for it to be idle while

they were performed. Shingo denoted as Internal set-up.


SMED methodology In 1957 Shingo improved the SMED

methodology. Placing an extra table in a Mitsubishi Company

machine. Convert some of the internal set-up tasks to external set-up

operations.

Shingo reduced the set-up time for a screw machine manufacturer from 8 hours to 58 seconds. At the Mitsubishi Company from 24 hours to 2 minutes

and 40 seconds.


SMED. 4 conceptual stagesExternal

Set-up

Preliminarystage

Current set-upstudy

Firststage

Separating internal and

external set-up

Secondstage

Converting internal set-up

to external set-up

ThirdStage

Streamlining all aspects of

the set-up process

InternalSet-up


Preliminary stage

Studying the current set-up process because simply put “what is unknown cannot be improved”. Know the process, the variability and the cause(s)

that produce this variability. Collect values for the set-up times.

set-ups can be frequent or sporadic. By means of the time study process.


Preliminary stage

the SMED’s goal is not to eliminate specialists’ job. set-up specialist opposition can lead to project

failure.


Separating internal and external set-up

Classify set-up operations according to the given definition of external and internal set-up. It takes into account the same operations and

duration included in the current method. Without improving any particular operation.


Separating internal and external set-up

Assure that the operations defined as external set-up can all be carried out with the machine running. Time to get the necessary tools and materials is not

allocated to the operators.

It is possible to reduce the exchange time by as much as 60% without any capital investments.


Converting internal set-up to external set-up

The set-up process time reduction from the first stage can be very significant but is not where SMED ends.



This stage examines two important aspects. Re-evaluate the internal set-up.

Check or see if some of them were considered erroneously as internal.

Look for alternatives that allow internal set-up to be carried out in whole or in part as external operations.

For example, is it possible to screw a die to a press before placing it inside the press chamber?



This stage will require an economic investment. Carry out a cost justification. Sometimes the investment will be necessary in

spite of the economics.



Other important aspect to consider. New process or system reliability. The possible appearance of new operations. The benefits and possible risks of the new process.

It is possible to achieve set-up process time nearing ingle minutes (< 10 minutes)


Streamlining all aspects of the set-up process

This stage tries to improve all the set-up operations. Both internal and external. Trying to eliminate some operations.

SMED methodology recommends that one follows systematically these four stages. Common sense -> not be invested in operations that

previously have not been optimized.


Streamlining all aspects of the set-up process

“stage 3”. Improvement of the external set-up operations. Revisit of the internal activities that have not been

possible to convert into external.


First stage tools

Numerous time wastes take place in many set-up processes. Materials are moved to the warehouse with the

machine stopped. Tools and dies are supplied late, or incorrectly. Tools and dies that are not needed, are taken back to

the supply room before starting the machine.


First stage tools

Some required screws and tools were not collected during the set-up process.

Some nuts are just too tight when trying to remove them.

It is necessary to eliminate all these wastes.


First stage tools

Try to answer certain questions before starting the set-up. What has to be done before starting the change? How many screws are necessary in order to fix the

die? Of what type? What tools are necessary? Are they prepared for

proper conditions? Where should the tools be placed after using them?


First stage tools

A group of visual controls have been developed.

Checklist. Questionnaire that should be checked before each

set-up process. Verify in advance that all elements that should be

prepared are in fact ready and available. Can be universal for all products changeover or

specific for each product.


First stage tools

Check panel placed next to the machine. Small number of tools or exclusive tools.

The worker can visually check if all the necessary tools are located.

In some check panels the tools are silhouetted. Another strategy is to code the tools with two

stickers. A sticker is placed in the machine and another is placed

on the tool.


First stage tools

Function checks. The checklist or the check panel do not show the die

and tools status. Material inlays.

Special devices for checking the molds before placing them in the machine.

If the company does not own one ->second stage.


First stage tools

Parts and tools transportation improvements. Transportation from the warehouse to the work area

should be carried out before the exchange begins. “traditional press exchange process”

Removes the used mold -> loads it in a crane -> takes it to the warehouse -> loads the new mold -> place it.

“new changeover process” Load the new mold -> leave it next to the machine -> take out the

mold -> leave it next to the machine -> loads up the new mold -> set the machine into operation -> carry the used mold to take it to the warehouse.


First stage tools

This “new changeover” looks like it takes longer than the traditional method. According to Shingo’s definition of set-up time, the

time with the machine stopped is drastically reduced.


Second stage tools

The second stage usually runs parallel with the third stage. SMED methodology offers some recommendations that

facilitate complex cases studies. Movements around the machine should not be questioned.

Will be analyzed in the third stage. It is not that some operations will be eliminated.

There are several methods broadly intended to enhance the set-up process.


Endless material method

When a reel is empty, it should be removed and replaced with a full one. Rolling mill or on packing machines.

The changeover time of reels could potentially be eliminated if the end of a reel is welded or tied to the beginning of the following one. The product made with the welding seem would be scrape.


Endless material method

Temporary containers. If it is not possible to weld or tie the reels to

carry out the changeover operation. Save set-up time considerably because they

eliminate the movements to locate and bring in the new reel.

If the reels allow it, it might be possible to tie the previous reel with the following reel and with a simple turn, carry out the exchange.


Press die preheat. There are devices that heat the molds up before being placed

in the machine. The main concern in this case is labor safety.

Function standardization. Standardize some measures (height and depth).

The set-up process should be as safe as before. The quality of the manufactured pieces should not be adversely

affected. Add new functionalities or features to the mold.

Second stage tools


Second stage tools

Tools duplication. Have two or more identical elements (cranes, tools, pallets,

…) to reduce the set-up time. A single six pack is as easy to handle as a single can of soda.

With a double crane it is possible to prepare the next mold and to extract the previous one without the need of removing and placing the molds again.


Third stage tools

The improvement or elimination of an operation requires reengineering some aspect of the product or process. it is possible to make the operation in a different

way? Is this operation necessary? Is this procedure the most appropriate?


Third stage tools Up to this stage, external operations have not been

analyzed. Will the set-up specialist have enough time?

Schedule the changeovers so that the specialists are not needed at the same time in two machines.

Internal operations can be improved. Analyze in detail the movements around the machine. Determine the optimal number of workers that should take

part in the set-up process.


Improving tool storage. Indicators’ strategy

Begin with the 5S’s. Organize tool storage in an efficient way.

Keeping high use items close for easy access. Organizing the tooling so that it is easily located

and identified. The 5S methodology offers a common

orientation when choosing the coding standards.


Parallel operations

For large machines, it is necessary to carry out operations at the front of the machine as well as at the back of it. The worker can waste important set-up time when

walking around the machine. The set-up time and complexity can be reduced

with the help of a second worker.

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Parallel operations

Utilize a task map to indicate what operations will be carried out by each worker Starting with the

initial situation.

Worker procedure1 Remove front bolts2 Movement to machine back side 3 Remove back bolts4 Remove back wiring5 Movement to machine front side6 Remove front wiring7 Put used die up8 Lift used die9 Move used die next to machine

10 Remove used die11 Move crane to new die12 Put new die up13 Lift new die14 Move new die to machine15 Get new die down16 Fix front Bolts17 Movement to machine back side18 Fix back bolts19 Fix back wiring20 Movement to machine front side21 Fix front wiring22 Fix new machine parameters


Parallel operations Two workers executing the exchange in a parallel way.

Table shows task sharing and those tasks that can be carried out simultaneously as well as the times where the workers should be waiting.

First worker procedure Second worker procedure1 Remove front bolts 1 Remove back bolts2 Remove front wiring 2 Remove back wiring3 Put used die up4 Lift used die5 Move used die next to machine6 Remove used die7 Move crane to new die8 Put new die up9 Lift new die

10 Move new die to machine11 Get new die down12 Fix front Bolts 3 Fix back bolts13 Fix front wiring 4 Fix back wiring14 Fix new machine parameters


Parallel operations Allows the Lean thinker to discover which are the most important tasks that should be

improved.

Labor safety, once again, is a priority in this type of synchronized work. Safety mats that stop the machine when they are activated. Confirmation buttons. …

First worker procedure Second worker procedure1 Remove front bolts 1 Remove back bolts2 Remove front wiring 2 Remove back wiring3 Put used die up 3 Movement to machine front side4 Lift used die 4 Fix new machine parameters5 Move used die next to machine 5 Movement to machine back side6 Remove used die7 Move crane to new die8 Put new die up9 Lift new die

10 Move new die to machine11 Get new die down12 Fix front Bolts 3 Fix back bolts13 Fix front wiring 4 Fix back wiring


Third stage tools

One-Motion Method. Perform more than one task simultaneously.

Electric and hydraulic connections.


Third stage tools

Functional clamps. Devices that are used to passively hold an

object in a fixed position with the minimum effort.

The SMED methodology seeks to eliminate the use of screws and nuts as fixing elements.

Pear-shaped holes. U-shaped washers rings.


Third stage tools

Functional clamps. C-shaped washers. Guttered thread. Single-movement method. Reduce the tools variety.


Eliminating trials and adjustments

Can represent 50% of the total changeover time. They are not only decreased but eliminated.

A set-point should be used instead of an adjustment. Without applying the trial and error method.

The adjusting procedures must be written The machine parameters value should be specified.

OTED (One Touch Exchange of Die).


Process Automation

The last resource after the successful implementation of the previous methods. Process automation supposes high investments

costs. Regardless of its expensive implementation,

in some cases it is the best alternative.


Zero changeover

When Shingo died in 1990, Sekine and Arai continued his work. They tried to achieve set-up times of less than a

minute. They create a strategy called Zero changeover.


Zero changeover

The only way to achieve set-up times near to seconds was to automate the exchange process. Represents large investments. Many of the achieved improvements, came from ideas

developed by Shingo.


SMED effects and benefits

Easier set-up process. New changeover procedures.

Set-up process is simplified and easier to carry out. Many of the operations can be carried out by the

majority of the employees. Increased safety also results from the improved

changeover simplicity. Eliminate defective parts.


SMED effects and benefits On-hand stock production.

Manufacturing batch size can be decreased as well. Work-in-process will decrease.

Mean time of material flow will decrease. Lead time will decrease too because it is directly related with the

time of material flow.

Workplace tasks simplification. Tool coding, a clean and upstanding machine

environment. Easier to locate tools.


SMED effects. Productivity and flexibility

The main benefits. Productivity. Flexibility.

Productivity. Decrease the machine’s load in order

to increase the productive period. SMED’s principal benefit is to

increase flexibility as it will be show next.

pi si

pi si pi si

Production (pi)

Production (pi)

set-up (si)

set-up (si)

Productivity

Flexibility



Productivity increase. SMED is an alternative among other methods

Increase in flexibility. SMED is the only solution

Buying a new machine does not provide an increase on the flexibility.



set-up (si)

set-up (si)

2 ProductosProduction (pi) set-up (si)

2 Products

Production (pi) set-up (si)

M1

M2

pi set-up (si)

4 Products

pi set-up (si)

Production (pi) si

2 Products

M1 si Production (pi)

4 Products

sisi sisi

Investing in SMED implementation

Buying a second machine


Economic benefits

Economic benefits depend on the machine situation in which the SMED is applied. Saturated machine.

Liberate the machine from its load time to increase the machine availability

The benefit takes place due to the economic margin in the sales increment.


Economic benefits

Not saturated machine. The necessary time to carry out a production order will

decrease. Saved cost in the workforce.

If the goal is to increase flexibility can be impossible. Qualitative benefits derived from SMED.


Summary

This chapter has presented a basic but helpful methodology to reduce the set-up time in a machine.

SMED’s methodology proposes the arrangement of the needed tools used in the set-up process before the machine finishes the previous lot.


Summary

The main benefit of the set-up time reduction is the increase in the flexibility of the production.

Nevertheless, the economic justification of a SMED project, focus on flexibility increment, is quite difficult.

Equipment Efficiency: Availability, Q uality and SMED

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