Equipment changeover time. Quick changeover of equipment. Examples in detail

Emergence of SMED

In the spring of 1950, I was doing research at the Mazda Toyota Kogyo plant in Hiroshima to improve production efficiency. Then three-wheeled cars were produced there. Toyo wanted to expand the bottlenecks created by the 350, 750 and 800 ton stamping presses for large body parts, which were working at a partial load. I inspected the production and asked the head of the department in charge of production to allow me to run a timing for a week to determine how the presses work. He replied that it would be a waste of time: he already knew that it was the presses that were responsible for creating bottlenecks, and he put the most skilled and conscious workers to work for them. Three presses worked around the clock, and he believed that the only way increase production - purchase additional equipment. He really hoped that the upper management would do just that.

“Well, that’s bad,” I said. “But maybe I can still carry out such an analysis?” If it turns out that there is no other way to eliminate bottlenecks, then I will recommend to management to purchase additional equipment. After that, I was allowed to conduct such a study.

On the third day, the dies were changed on an 800-ton press. The workers removed the old die and started running around the press. I asked the operator what was going on. He said, “One of the mounting bolts for the new die is missing. I was sure that it was in the stamp, but I can’t find it, although I have already looked everywhere. ”

“When you find him, will you go to the press?” I'll be waiting for you here," I said.

“Good,” he said. “But still, when you're here, I get nervous.

I sat down near the press and waited. More than an hour later, the operator came running in a sweat, bolt in hand, shouting gleefully, “Here it is! I found him! In fact, I didn't find it. I just took a long bolt from a nearby press, cut it off and threaded it. Therefore, it was delayed. Believe it or not, it wasn't easy!" - he said.

I sympathized with him, but then another thought began to bother me: You cut a bolt taken from another press. And when you need to change the tool on that press, what will you do? What happens to you all the time?

- No, not all the time. Such incidents happen from time to time,” he replied.

That's when the idea came to me that there are two fundamentally different types of changeover: internal adjustment— operations of mounting and removing stamps, which can only be performed with the press turned off; external adjustment– actions for the transportation of old stamps to the warehouse, delivery of new stamps to the press; these operations can be performed without shutting down the press.

Bolt preparation is an external operation. It did not make sense to stop the work of the 800-ton press due to the lack of a bolt. It was only necessary to clearly work out the procedures for external changeover, including checking the presence of bolts for the upcoming changeover.

We have developed a meticulous procedure for collecting and storing all bolts in their respective boxes. We have also improved the changeover process by performing all possible operations as external. This increased efficiency by about 50% and the bottleneck was resolved. After that, I made it a rule to clearly distinguish between internal and external operations.

This is how the newborn SMED concept took its first steps on the Toyo Kogyo.

Second episode

In the summer of 1957, I was asked to do research at the Mitsubishi Heavy Industries shipyard in Hiroshima. When I asked the repair plant manager, Mr. Matsuzo Okazaki, what was the problem, he said that the large-sized planer for machining diesel engine parts was not used at its design capacity and it was desirable to simplify this operation.

After analyzing the production process, I found that the markings for centering and for the dimensions of the engine block were made directly on the machine table. This greatly reduced the speed of work. As I discussed this with Mr. Okazaki, it dawned on me: why not install a second table for the planer and do the marking operation on it separately? In this way, we could simply change tables between batches, and this would significantly reduce the changeover time when doing machining. Mr. Okazaki agreed to this change.

The next time I arrived at the factory, I found that the installation of the additional table was complete. The implementation of this solution allowed to increase productivity by 40%. Both Mr. Okazaki and I were delighted with this result and congratulated each other on this achievement, although I now regret one thing. If I had already been able to realize the full significance of the transfer of internal operations to external ones, then the SMED system would have been developed twelve years earlier.

Third episode

In 1969, I visited the body parts shop at the main plant of the Toyota Motor Company. The foreman, Mr. Sugiura, told me that they change a 1,000 ton press in four hours, although Volkswagen in Germany can change a press like this in two hours. Mr. Sugiura received clear instructions from management to meet even less time.

Together with the foreman and the director of the plant, we began to look for a solution to the problem. We began to clearly separate the activities into internal and external, trying to optimize them separately. After six months, we were able to reduce the changeover time to an hour and a half.

We were all very pleased with this success, but when I returned to the shop a month later, Mr. Sugiura had some interesting news for me. The management ordered him to reduce the changeover time to three minutes! For a moment I was stunned. But then the inspiration came: why not convert internal operations to external ones?

New ideas began to emerge quickly one after another. On the whiteboard in the boardroom, I laid out eight methods to reduce changeover time. Using this new concept, after three months of hard work, we were able to achieve the desired time of three minutes. In the hope that any changeover can be done in less than ten minutes, I have named this concept SMED. The SMED system was later adopted by all Toyota enterprises and continued to develop as one of the main elements of the Toyota Production System. Now its use has spread throughout Japan and the world.

Mr. Taiichi Ohno, former Vice President of Toyota Motor Company, wrote about SMED in June 1976 in the article "Introducing Wisdom into the Enterprise" ( Published in Management magazine published by the Japan Management Association):

work time

It was irrational. Since we also wanted to carry out scheduled repairs during business hours, we began to study how to reduce changeover times as much as possible. Shigeo Shingo of the Japan Management Association promoted the "less than ten minute die change system", and we thought that such a concept would be very useful to us. It so happened that after we spent half a day on changeover, the machine worked for only ten minutes. It is logical to assume that if changeover takes half a day, then production should go at least no less. But then we would have a lot of excess products that we could not sell. We are now looking into ways to reduce changeover times to a few seconds. Of course, this is easier said than done. But be that as it may, the time for changeover must be reduced. ”

This excerpt highlights the impact of reducing changeover times on improving overall performance.

The development of the SMED concept took a total of 19 years. It arose from a deep understanding of the practical and theoretical aspects rationalization of changeover. Toyota Motor Corporation's demand to reduce press changeover time from four hours to one and a half played an important role.

I would like to emphasize that the SMED system is based both on theory and on many years of experimental practice. It is a scientific approach to reducing changeover times that can be applied to any plant and any equipment.

MAIN STAGES OF THE PROCESS CHANGEOVER

Usually changeover procedures are presented as infinitely varied, depending on the operation and the type of equipment used. However, if we analyze these processes from a different point of view, we can see that all changeover operations consist of a certain sequence of steps. At traditional way changeover time distribution usually corresponds to that presented in Table. 3.1.

Table 3.1. Changeover process steps

Let's consider each of them in more detail.

Preparation, post-operative adjustment, check of workpieces, tools, etc. On the this stage there is a check of availability in the right place and suitability for work of all materials and tools. This stage also includes the period after processing, during which the products are removed from the equipment and transported to the storage site, the time to clean the equipment, etc.

Installing and removing cutters, tools, workpieces, etc. - operations for removing products and tools after completion of processing and installation of parts and tools for the next batch.

Measurement, parameter setting, calibration - all measurements and calibrations that need to be performed to perform a production operation - alignment, marking, temperature or pressure measurement, etc.

Trial runs and adjustments. Adjustments are made after processing the trial product. The higher the accuracy of measurements and calibration in the previous step, the easier the upcoming adjustment.

The frequency and duration of trial runs and adjustments is determined by the qualifications of the commissioning engineer. The biggest challenge in changeover operations is getting the equipment right. The largest proportion of dry run time is associated with these adjustment problems. If we want to make trial runs and adjustments easier, we must understand that the most effective approach is to increase the accuracy of measurements and calibrations in the previous step.

Changeover Rationalization: Key Steps

The main stages of the changeover improvement process are shown in fig. 3.2.

Rice. 3.2.

Preliminary step: changeover conditions are not divided into internal and external

When carrying out changeover according to the traditional scheme, external and internal operations do not differ; what could performed as an external operation is performed as an internal operation, so the equipment is idle for a long period. When implementing SMED, one must study the actual conditions in the workplace very carefully.

The best approach would probably be continuous production analysis performed with a stopwatch in hand. Such an analysis, however, is time-consuming and highly skilled.

Another possibility is sample study of work. The problem with this option is that the sample works only accurately reflect the actual picture when they are often repeated. This method may not be suitable if few actions are repeated.

The third interesting option is to study the actual conditions in the shop by interviewing workers.

The best method is video filming the entire conversion process. It is extremely effective if the record is shown to the workers as soon as the changeover is completed. Letting workers have their say often provides a remarkably clear, useful insight into problems. In many cases, this new understanding can be put into practice immediately.

While many consultants advocate in-depth, continuous review of production to improve the changeover process, in fact, informal observation and discussion with workers is often sufficient.

Step 1: Separate internal and external changeover activities

Most important step when implementing SMED, distinguish between internal and external changeover activities. I think everyone will agree that parts preparation, maintenance, etc. do not have to be done with equipment off. However, it is surprising how often this is done.

If, however, special studies are carried out to transfer as many operations as possible from internal to external, then the time of internal operations performed with the equipment turned off can usually be reduced by 30-50%. Thus, a clear understanding of the differences between internal and external actions is the essence of SMED.

Stage 2: Convert internal activities to external ones

I just mentioned that you can usually cut changeover times by 30-50% by separating internal and external procedures. But even such a huge reduction is not enough to achieve the goals of SMED. At the second stage - the transformation of internal changeover into external - it is necessary:

check all operations in order to find out if any actions are mistakenly perceived as internal; find ways to transform these operations into external ones. These include, for example, the heating operation, which was previously carried out only after the start of changeover, and the centering operation, which can be performed before the start of production.

It is often possible to convert an internal changeover into an external one by looking more closely at its function. It is extremely important to identify a new point of view, not bound by old habits.

Step 3: Simplify all aspects of the changeover operation

Although it is sometimes possible to do this in less than ten minutes by simply converting internal actions into external ones, in most cases this is not possible. That is why we must first make a concerted effort to simplify all elementary internal and external operations. Thus, at stage 3, a detailed analysis of each elementary operation is needed. The following examples show the success of steps 1, 2 and 3.

At Toyota Motor Company, the bolt cutter's internal changeover time, which was previously 8 hours, has been reduced to 58 seconds.
At Mitsubishi Heavy Industries, the internal changeover time of a 6-spindle drilling machine, which was previously 24 hours, has been reduced to 160 seconds.

It is not necessary to perform steps 2 and 3 sequentially, they can be performed almost simultaneously. I've separated them to demonstrate the two prerequisites: analysis first, then implementation.

CONCLUSION

The SMED system has been developed over 19 years based on a thorough analysis of the theoretical and practical aspects of changeover improvement. Thus, analysis and implementation are the backbone of the SMED system and should therefore be part of any improvement program.

There are two types of changeover actions - internal and external. The three main steps to improving the changeover process include separating the two activities and converting internal changeover operations to external ones. When this is done, all aspects of changeover should be simplified as much as possible. Changeover process improvements can be made at any stage.

Chapter from Shigeo Shingo's book "Fast changeover. Revolutionary production optimization technology" courtesy of the publisher

Perm National Research Polytechnic University

Abstract on the topic

"Fast equipment changeover"

Performed

Student MK-12-1

Berdnikova M.D.

Checked by: Professor,

Doctor of Technical Sciences

Popov V.L.

2015, Perm

Introduction

Modern companies constantly developing, trying to improve products, production. This gives significant competitive advantage, increase the share of customers and increase profits. The main task of companies is to reduce tangible and intangible costs, to increase production time, and due to the quantity of products produced. There are many methods for reducing costs. One of the methods used by companies is the rapid changeover of SMED equipment. The purpose of the work is: The study of the method of rapid changeover of equipment.

· The study of theoretical material on this topic

· Analysis of the application in practice of the method of rapid changeover of equipment

· Statement of conclusions

Theoretical part

Rapid changeover is a changeover/retooling process organization concept that can significantly reduce the time spent on changeovers.

The concept originated in Japan in 1950 at machine-building plants, the author of the concept is Shigeo Shingo, who developed this concept for 20 years (1950 -1970).

Assuming that any changeover can be done within 10 minutes, he called his concept SMED.

The SMED system is applied

To change the range of products,

For quick changeover of production lines,

To reduce production downtime and increase the flexibility of the production process.

The tool is based on the fundamental division of actions performed during changeover into internal and external:

· Internal setup - part of the changeover process operations that are performed while the equipment to be adjusted is stopped.

· External changeover - part of the changeover process operations that are performed during the manufacture of good products on the equipment to be set up.

The implementation of the SMED system includes:

Careful study and analysis of the actual conditions in the workplace. The timing of the entire changeover process is carried out (from the moment the production of product “A” is completed until the production of product “B” begins), all actions are recorded in great detail (took, fixed, transferred, etc.). It is recommended to film the current changeover process on video for the convenience of subsequent analysis.

Separation of actions into internal and external readjustment. At this step, analysis is carried out: all recorded actions are classified into internal and external, as well as those that must be done before the equipment shutdown, during the shutdown and after it.

Converting (where possible) internal changeover activities to external ones. The analysis continues, the actions that can be performed without stopping the equipment are highlighted (pre-assembly, adjustment, warm-up, preparation of tools, equipment, etc.)

Simplification and streamlining of all elementary internal and external changeover operations based on their detailed analysis. Development of solutions that allow eliminating adjustments, settings, performing simplified fixes, organizing parallel execution of work, etc. This step may require changes in the design of tooling and fixtures, which may require a significant investment. Also, the development of solutions to improve logistics (delivery of equipment, fixtures, tools, etc.), improve service, reduce travel, etc.

Documenting new procedures and activities. Development of an operations improvement map.

If necessary (if changeover takes more than 10 minutes), repeat all steps again.

Thus, by a simple logical analysis, even if one does not invest in redesign or manufacture of fixtures (fasteners, etc.), one can find huge potential for improvements in any changeover process.

Even carrying out the simplest analysis with the maximum transfer of internal work to external work and standardization of the result helps to significantly reduce changeover time and stabilize the process.

Despite the existing myth that the implementation of this tool does not require absolutely no costs, it is rightfully the most expensive, since a significant part of the potential for reducing changeover time is realized by changing the design (fasteners, fixtures, etc.), i.e. after investing certain funds.

The result of the analysis and decisions taken there should be a changeover standard that clearly regulates the sequence of actions, settings and start-up parameters, required time and means for its implementation (tools, equipment, etc.). Of course, the changeover standard must be supported by the managers, ie. Managers must ensure that nothing stands in the way of following and monitoring compliance with the standard.

The main points that you should pay attention to when using the described tool:

· Determination of clear goals and the required result of the work. Frequent errors - improvement for the sake of improvement, or the cost of time and money for the sake of reducing several hours of work for the adjuster. It is necessary to keep in mind the main purpose of the tool and be clear about the desired result before starting work.

· Learning and following each step correctly. You need to make sure that the team clearly understands the sequence of steps to be performed, do not skip any step or shorten it.

· Standardization of the result completes any improvement. The result must be standardized, and the standard is clear and precise.

· Formation of habits and control over compliance with the standard. Managers must control the standard, and employees must follow it.

The results of work using SMED should be:

.Standardized optimal changeover sequence including preparatory work, directly change of equipment (tool).

2.Standardized changeover times.

.Standardized places and methods for bringing equipment and performing external operations.

.Reduction and standardization of lot sizes and product inventory levels as a result of increased changeovers.

Fast changeovers provide production flexibility and reduce waste associated with:

· overproduction;

· excess inventory;

· equipment and operator downtime.

This method, like any other, has its advantages and disadvantages.

Advantages: Reduced downtime, minimized inventory, focused on small-batch or made-to-order production, quickly adapting to changes in demand.

Weaknesses: Requires long-term discipline and significant change management skills.

The frequency and duration of dry runs and adjustments depends on the skill of the commissioning engineer.

Application in practice

The Matsushita Electric division was established in 1956 to manufacture National washing machines. It now manufactures dishwashers and double-chamber washing machines on a 1,000-meter line at a rate of about one machine every six seconds. Based on the policy of "excellent quality, well-organized production and respect for people", the company was able to sell 18 million items in 1980. National washing machines are in steady demand not only in Japan, but also in 68 countries around the world.

SMED APPLICATIONS:

.Changeover of lubricants. Grease application is one of the many operations in a washing machine assembly line. Previously, lubricant was applied to the right places manually, now it happens automatically.

.Automatic change of limiters on pallets. Installation stops are mounted on pallets used in the washing machine assembly line

.Change of dyes for protective coating operations by sintering.

.Reduced mold changeover time. In recent years, the number of models of washing machines has increased in accordance with the requirements of customers, which has led to diversification in the industry. Since operators don't like to spend a lot of time on changeovers, the traditional approach has been to produce in as large batches as possible to keep changeovers to a minimum. With this approach, however, inventories increased as the number of models and parts increased. Gosei was founded in 1949. Since then, the company has successfully developed and improved a number of high polymer products for the automotive industry. Toyoda Gosei designs and manufactures plastic, cork, urethane, and other parts, and has commanded an overwhelming market share in many areas, including steering wheels, various hoses, and piston plugs. The capitalization of the company in 1978 was 3.3 billion yen, billion yen, sales - 106.4 billion yen, the number of employees - 4600 people. Eight factories produced 12 thousand items of products.

The market situation for the automotive industry was favorable until 1977-1978. But after the oil crisis in 1979, a decline in consumer demand forced manufacturers to expand the production of small cars and adjust their policies towards higher quality. As competition intensifies in the industry, both in the country and in the world, only price reductions with high quality products allowed the company to survive. Toyoda Gosei tried to find ways to reduce the cost of its products. In 1976, under the leadership of Toyota Motor Corporation, the company began to introduce production system Toyota, whose fundamental principle is the elimination of inefficiency. This method involves reducing prices and increasing efficiency, striving for an ideal situation, taking into account the following points:

· workers, machines and other objects work without losses;

· workers and machines perform only the work that adds value;

· product release time is the total time of all processing (i.e. lead times are subject to the maximum reduction).

The aim of these measures, which rest on the two cornerstones of just-in-time and worker-assisted automation, is to produce at the lowest cost and only sellable goods, and without delay. In other words, this method belongs to the field of management.1

Just-In-Time (JIT) manufacturing is a very important principle. When applied to an individual production process, the JIT concept means the production of the required number of products at the right time. This is achieved by minimizing inventory, synchronizing production processes and creating a continuous flow with a minimum amount of work in progress.

SMED APPLICATIONS:

· Changeover of cutters when machining fittings

· Changes in punch changeover operations in cold forging

Bridgestone Tire Co., Ltd. founded in 1931 in Kurume, Fukuoka Prefecture. It was the first Japanese tire manufacturer with Japanese capital, and the basis of its policy was the production of car tires in its own country using domestic technologies. In addition to the fact that the company was called upon to satisfy the needs of local consumers and provide inexpensive, high-quality tires, it set a goal to cover the cost of importing rubber through the export of finished products.

SMED APPLICATIONS:

· Improving the operation of changing drums of different widths in tire molding

· The introduction of the system of demonstration adjustments in 1977, along with activities to improve production efficiency, the introduction of the SMED system has yielded significant results. But in the next two or three years, the results of the implementation did not match our efforts. For this reason, it was decided to approach SMED by introducing a system of demonstration adjustments and training.

Plant directors, service heads, department heads and all interested employees observe the actual operation of the setup operations in the shop, look for problems, exchange opinions on methods for solving them. The announcement of the demonstration adjustments is posted at the workplace, and the record figures are reported to everyone. Conduct education and training to develop the ability to recognize and solve problems. Changeover improvement is carried out in the form of a game, cooperation among employees is stimulated.

Conclusion

The SMED system is a completely new way of thinking about production. The SMED system is based on both theory and many years of experimental practice. It is a scientific approach to reducing changeover times that can be applied to any plant and any equipment. Using the example of companies, one can be convinced that the SMED system brings its results, and it can be applied in any areas of production, depending on the goals of the enterprise. It is also necessary to clearly understand what the company wants to achieve as a result, in order to clearly define the object, timing and costs for the implementation of the SMED system. This method has its advantages and disadvantages, but if you approach the process of its implementation and implementation correctly, the method will help the company achieve its goals.

changeover operation cutter control

1.Shigeo Shingo. Fast changeover. Revolutionary production optimization technology. - Alpina Publisher, 2006 - 293 p.

.Productivity Press development team. Lossless Manufacturing - Quick Changeover for Workers. - Institute for Comprehensive Strategic Studies, 2009 - 104p.

.Kuzmin A.M., Vysokovskaya E.A. Creative and analytical tools for creating innovations, 2011-128s.

Quick changeover (SMED; Single-Minute Exchange of Dies - lit. "quick change of molds") - changeover / retooling of equipment in less than 10 minutes.

SMED is an acronym English term Single Minute Exchange of Dies (quick change of dies). In essence, the SMED system is a set of theoretical and practical methods, which allow to reduce the time of equipment setup and changeover operations to ten minutes. This system was originally designed to streamline die changing operations and related equipment changeovers, but the "quick changeover" principles can be applied to all types of processes.

It took Shigeo Shingo nineteen years to develop the SMED system. While studying changeover operations in many factories, he discovered two important things that formed the basis of SMED:

Changeover operations can be divided into two categories:

Internal changeover activities, i.e. operations that are performed after the equipment has stopped. For example, a mold can only be changed when the press is stopped.
External changeover activities, i.e. operations that can be performed while the equipment is running. For example, mold bolts can be picked up and sorted while the press is running.

Converting as many internal changeover operations as possible into external ones allows you to reduce the equipment changeover time by several times.

One of the first experiences of implementing the SMED system in manufacturing process proved to Toyota that a large 1,000-ton press can be set up not in four hours, as was done before, but in just three minutes. Changeover speed is essential for any company looking to build their manufacturing process around just-in-time and small batches. Fast changeover for such companies provides an opportunity to quickly change the model range and avoid the accumulation of excess stocks of products in the warehouse.

The SMED system is the most efficient approach to reduce changeover times. Thanks to this system, you will be able to significantly reduce the number of complex, lengthy and unproductive equipment changeovers, or even get rid of them, which will undoubtedly not only facilitate your work personally, but also make your company more competitive.

SMED Implementation Goals

Reduce equipment downtime;
Reduce the size of production batches;
Reduce inventories of work in progress - interoperational inventories of parts, materials, semi-finished products;
Expand product range

External changeover operations

External operations - operations that can be performed while the machine is running
Examples:

Get a stamp or tool from the warehouse;
Transportation to the machine;
Select and sort mold mounting bolts
Prepare party documents

Internal changeover operations

Internal operations - operations that can only be performed while the machine is stopped (turned off)
Examples:

Remove cutter;
Fix the stamp;
Tighten the nut that secures the snap;
Replace mold.

Stages of traditional equipment changeover

Analysis of the changeover process: Timing of the changeover process, video recording of the changeover.

Why timekeeping and video recording are needed:

Set the longest and most labor-intensive operations;
See what tool is being used;
See what is missing;
See what was not prepared;
Determine what can be done better, faster, easier
Not to punish operators;
Not for assessing the workload of operators

Changeover video:

To shoot not a person's face, but what he does - to shoot his hands;
Do not stand still, but move along with the adjuster;
When the setter works with a tool, one must film what tool is being used and how it is being used;
If the video camera has the ability to set a timer in the frame, it must be turned on, then when viewing and analyzing, you can use the timer readings;
If there are several adjusters, several video cameras should be used. If there is only one video camera, it should follow the most qualified installer;
The camera operator must not enter the danger zone

How to reduce the execution time of operations?

Determine if the operation is external or internal;
Determine why an external operation is performed as an internal one;
Perform all external operations as external;
Make a re-timing;
Determine the longest and most labor-intensive operations;
Reduce the time of the most time-consuming and labor-intensive operations

Optimization of the transport of parts and tools

How can the execution time be reduced?

Application of checklists;
Carrying out functional checks;
Use of auxiliary equipment;
Implementation of parallel operations;
Use of functional clips;
Mechanization

Source: "News in detail. Newspaper of Novosineglazovsky village", October 2013.

We thank the OMK Press Center for providing this material.

- Who is involved in the development of changeover standards and how is the implementation process going?

The working group, which includes a senior site foreman, a worker, a site technologist and a standardizer, creates a standard - a document that is located at the workplace.

Before standardizing changeover, it is necessary to set a specific goal - for example, reduce the duration of the operation, improve the quality of the operation, stabilize time and quality. Further, the working group, according to a certain procedure, forms a standard for readjustment. At the same time, the working group should apply the means of improvement, which we will discuss a little later. Then the stage of training ordinary employees to work according to the standard takes place. The last one is performance control. On the this moment the second stage of the implementation of the project "Standardization of Operations" is underway, within the framework of which standards will be introduced at key operations of production sites.

- How is it implemented in practice?

On site 1.1. we standardized the changeover on the CAB 300 welding complex. Based on the results of observations and timing, it became clear that the welder, in order to perform this technological operation, repeatedly descended from the platform, took the equipment, lifted it up, installed it, and then repeated the same actions. Also, for fastening the equipment, the worker had bolts of different diameters, difficulties with fastening the bolts, and so on. The most optimal solution is to place the equipment within walking distance from the operator, to organize the work as far as possible, without involving an overhead crane. In addition, it is possible to use unified tooling fastening parts. For example, when installing tool A, one type of bolts and nuts is required, when installing tool B, another, and when installing tool C, a third. Sets of these bolts and nuts, as well as tools, look for a very long time. At the same time, for all types of equipment, you can use unified fasteners, which require one type of tool.

For example, the unification of equipment is very important in order to reduce the variability in the fastening of pipeline fittings (PDT). The simplest is to reduce the thread length of the tooling bolt. For example, the time to tighten one bolt is 5 minutes, but if there are 20 of these bolts, does it take 100 minutes? In this case, the idle rotation of the bolt is 3 minutes, and 2 minutes for tightening. It turns out that if we eliminate idle movements, then it will take 40 minutes to tighten 20 bolts. Accordingly, 60 minutes were saved. This is the simplest example of how changeover improvements can be applied - to eliminate technological and organizational losses.

- By what principle do you choose the operations to which it is necessary to apply technological changeover?

The plant is implementing the organizational project "Production Flow", within the framework of which maps of the production flow for each site have been developed. Of these, the operations that are the bottleneck or theoretical bottleneck are determined by calculation. This is clearly seen when at a certain stage of the manufacture of products there is an excessive storage of semi-finished products. We have identified a register of similar operations that require standardization, formed a schedule for the development of standards, which is carried out by working groups and is updated monthly.

- How else can you reduce changeover time?

You can minimize changeover time by investing and buying new equipment and tooling, spending millions of rubles. But you can go the way of standardization - while we try to simplify the procedure as much as possible without huge investments. There is a third option - this is to launch a constant process of improving the changeover standard, while involving the workers themselves in this procedure, because only they know all the pros and cons of their activities. When we found out that most people care about what they do. Accordingly, find out from them what shortcomings there are and eliminate them. Typically, this requires minimum investment and high results are achieved. The project also plans this work to improve standards.

- What effect is predicted from the introduction of changeover standards?

As intermediate results show, with standardization of changeovers at some key operations, it is possible to reduce the duration by 25-30%, or even more - this means that we can produce more products, respectively, and earn more. We described in detail all the steps of the operator, ensured the reduction of unnecessary transitions as much as possible and described the sequence of actions of the personnel, the application necessary tool, developed measures to improve the productivity of changeovers and so on. As I see it, now it is necessary to start the procedure for training employees, the process of introducing improvements in working standards, to achieve the stability of meeting standards in each work shift.

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Definition

SMED/Quick Changeover(Single-Minute Exchange of Die - English one-minute replacement of dies) is a concept for organizing the process of changeover / retooling of equipment, which can significantly reduce the time spent on changeover equipment.

The concept originated in Japan in 1950 at machine-building plants, the author of the concept is Shigeo Shingo, who developed this concept for 20 years (1950 -1970). Assuming that any changeover can be done within 10 minutes, he called his concept SMED.

Further development of SMED has led to the concept of OTED (One-Touch Exchange of Die - eng. replacement of dies with one touch) - the concept of replacing dies no longer than one minute.

SMED/OTED methods

The SMED / OTED methods are based on the discovery in the 50s of the XX century. Shigeo Shingo divides the changeover process into two types of operations:

Internal changeover operations(IED - Internal Exchange of Die) - operations that can only be performed on a stopped machine, such as mounting or removing a die.

External changeover operations(OED - Outernal Exchange of Die) - Operations that can be performed while the machine is still running, such as transporting the die to and from storage.

There are 8 main methods of the SMED system used to reduce changeover time:

1. Separation of internal and external changeover operations

It must be clearly defined which changeover operations must be carried out with the machine stopped and which can be carried out with the machine running.

2. Transformation of internal actions into external ones

The transformation requires a revision of the operations in order to check whether among the actions attributed to internal changeover, those that are actually or can be external.

3. Standardization of function, not form

Die shape standardization is costly, while function standardization only requires the uniformity of the parts needed for the changeover operation. For example, adding a plate or block to the edge of a die fixture standardizes the dimensions of that part only and makes possible application the same clamping device with different settings.

4. The use of functional clamps or the complete elimination of fasteners

In practice, the most commonly used fastening device is a bolt, but its application is sometimes very time consuming. For example, a bolt with 15 threads must be turned 14 times before it is actually tightened on the last turn. But only the last turn is needed when tightening and the first when loosening, the remaining 13 are lost movements. Bolts are not the only method of fastening, one-touch fastening methods using wedges, pins, and latches or springs as grippers that simply connect two parts reduce installation time to seconds.

5. Use of accessories

Some of the delays associated with internal setup adjustments can be eliminated by using standard fixtures. When a workpiece fixed in one fixture is machined, the next workpiece is set in the second fixture. When the processing of the first workpiece is completed, the second fixture is easily placed on the machine for processing.

6. Application of parallel operations

If the changeover operation requires setting operations on all sides of the machine, and if these operations are performed by one worker, then a lot of time and effort is spent walking around the machine. But when two people perform parallel operations, changeover times are typically more than halved due to the savings in movement. For example, an operation that takes 30 minutes for one worker will take only 10 minutes for two.

7. Elimination of adjustments

Typically, adjustments and test runs take up 50-70% of the internal setup time. Eliminating them is an amazing time saver. Adjustment elimination begins with the realization that setting switches/controls and adjusting are two distinct and separate functions. Adjustments can be eliminated by using a device to accurately determine the correct position of the limit switch/adjuster. Then the only operation required is setting the switch/controller. By far the best adjustment is no adjustment. For example, adjustment can be eliminated completely when the number of positions of the regulator is limited and unchanged.

8. Mechanization

Mechanization should be considered when every effort has been made to improve the changeover process in all the ways described above. Mechanization is essential for the replacement of large fixtures and dies, foundry and molds. The fastening of any parts can be done using air or oil pressure. However, investments in mechanization should be evaluated very carefully. While reducing changeover time by the previous methods from 2 hours to 3 minutes, mechanization is likely to reduce this time by no more than another minute.

Implementation stages

SMED provides a progressive approach to changeover improvement. There are 4 stages to go through:

Stage 1

At this initial stage, no distinction is made between internal and external actions. Many external activities, such as searching for tools and preparing a die, are performed while the machine is stopped. This causes an unnecessary lengthening of the setup.

Stage 2

This is the most critical stage in the implementation of SMED. It provides for the separation of internal and external adjustment operations. Compile a checklist including all parts, operating conditions, and steps to be taken while the machine is running. Then check the functioning of all nodes to avoid delays during internal adjustment. Finally, you need to research and implement the most effective method transportation of dies and other parts during machine operation.

Stage 3

Review the current changeover process to determine if any of the internal activities can be converted to external. For example, warming up the mold while the machine is still running eliminates the need to warm up the mold when the machine is stopped.

Stage 4

Examine internal and external setup operations to identify additional features for improvements. Consider eliminating adjustments and changing fastening methods.

Over the years, of several hundred SMED improvements, the most successful have been:

clear separation of internal and external changeover
if possible, complete conversion of internal to external setup
elimination of adjustments
fastening without screws