Equipment Efficiency: Availability, Q uality and SMED

Equipment Efficiency:Availability, Qualityand SMED Operations Analysis and Improvement 2010 Fall Dr. Tai-Yue Wang Industrial and Information Management Department National Cheng Kung University

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.

Thinking revolution The 5S Visual Control Workforce optimization Standard operations Poka-Yoke Jidoka TPM One-Piece flow Multi- functional workers Leveling Production Kanban SMED 1 20 11 12 9 7 16 JUST IN TIME 5 14 4 6 17 8 15 18 19 13 10 3 2 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

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.

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.

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.

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.

set-up costs Batch size 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!

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 stages

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.

Converting internal set-up to external set-up • 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?

Converting internal set-up to external set-up • This stage will require an economic investment. • Carry out a cost justification. • Sometimes the investment will be necessary in spite of the economics.

Converting internal set-up to external set-up • 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-upoperations. • 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.

Second stage tools • 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 • 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.

Parallel operations • Utilize a task map to indicate what operations will be carried out by each worker • Starting with the initial situation.

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.

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. • …

Equipment Efficiency: Availability, Q uality and SMED