Equipment changeover time. Fast equipment changeover. Examples in detail

Emergence of SMED

In the spring of 1950, I conducted research at the Mazda Toyota Toyota plant in Hiroshima to improve production efficiency. At that time, three-wheeled cars were produced there. Toyo wanted to alleviate bottlenecks caused by its 350, 750 and 800 ton large body presses that were operating at partial load. I toured the facility and asked the department head in charge of production to allow me to time it for a week to determine how the presses worked. He replied that this would be a waste of time: he already knew that it was the presses that were to blame for the formation of bottlenecks, and he assigned the most qualified and conscientious workers to work on them. Three presses worked around the clock, and he believed that the only way increase production - purchase additional equipment. He really hoped that senior management would do just that.

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

On the third day, dies were changed on an 800-ton press. The workers removed the old die and began 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’ve already looked everywhere.”

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

“Okay,” he said. “But I still get nervous when you’re here.”

I sat down near the press and waited. More than an hour later, the operator came running, covered in sweat, holding the bolt in his hand, shouting joyfully: “Here it is!” I found him! In fact I didn't find it. I simply took a long bolt from a nearby press, trimmed it and tapped it. That's why I was delayed. You can believe it was not 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? Does this happen to you all the time?

- No, not all the time. From time to time there are such incidents,” he replied.

That's when it occurred to me that there are two fundamentally different types of changeovers: internal adjustment— operations of installing and removing dies, which can only be performed with the press turned off; external adjustment— actions for transporting old dies to the warehouse, delivering new dies to the press; These operations can be performed without turning off the press.

Bolt preparation is an external operation. It made no sense to stop running an 800 ton press because a bolt was missing. It was only necessary to clearly work out the external changeover procedures, including checking the presence of bolts for the upcoming changeover.

We have developed a careful procedure for selecting and storing all bolts in appropriate boxes. We have also improved the changeover process by performing all possible operations as external ones. 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 at Toyo Kogyo.

Second episode

In the summer of 1957, I was asked to conduct research at the Mitsubishi Heavy Industries shipyard in Hiroshima. When I asked the director of the repair plant, Mr. Matsuzou Okazaki, what the problem was, he said that the large planer for machining diesel engine parts was not being used at its designed capacity and it was desirable to simplify the operation.

After analyzing the production process, I discovered that the markings for alignment and the dimensions of the engine cylinder block were made directly on the machine table. This greatly reduced the speed of work. As I was discussing this with Mr. Okazaki, it dawned on me: Why not install a second table for the planer and perform the marking operation on it separately? This way we could simply change tables as we move from one batch to the next, and this would significantly reduce the changeover time during machining. Mr. Okazaki agreed to this change.

The next time I arrived at the plant, I found that the installation of the additional table had been completed. The implementation of this solution made it possible 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 have one regret. If I had already been able to realize the importance of transferring internal operations to external ones, then the SMED system would have been developed twelve years earlier.

Episode three

In 1969, I visited the body parts shop at the main plant of the Toyota Motor Company. The site manager, Mr. Sugiura, told me that they can set up a 1,000-ton press in four hours, although Volkswagen in Germany can set up a similar press 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 activities into internal and external, trying to optimize them separately. After six months, we managed to reduce the changeover time to one and a half hours.

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

New ideas began to emerge quickly one after another. On the boardroom board, I outlined eight methods for reducing 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 accomplished in less than ten minutes, I called this concept SMED. The SMED system was later adopted by all Toyota facilities and continued to develop as a core element 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 “Implementing Wisdom in the Enterprise” ( Published in Management magazine, published by the Japan Management Association):

work time

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

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

The development of the SMED concept took a total of 19 years. It arose as a result of a deep understanding of the practical and theoretical aspects rationalization of changeovers. An important role was played by the requirement of Toyota Motor Corporation to reduce the press changeover time from four hours to one and a half hours.

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

MAIN STAGES OF THE CONVERSION PROCESS

Typically, changeover procedures are presented as infinitely varied, depending on the operation and 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. Stages of the changeover process

Let's look at each of them in more detail.

Preparation, post-operative adjustments, checking workpieces, tools, etc. On at this stage All materials and tools are checked for availability in the right place and suitability for the job. This stage also includes the post-processing period, during which the products are removed from the equipment and transported to a storage location, time for cleaning the equipment, etc.

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

Measurements, parameter setting, calibration - all measurements and calibrations that must be made to perform a production operation - alignment, marking, measuring temperature or pressure, etc.

Trial runs and adjustments. Adjustments are made after processing the trial product. The higher the accuracy of measurements and calibration at the previous stage, the simpler the upcoming adjustment.

The frequency and duration of trial runs and adjustments are determined by the qualifications of the installation engineer. The biggest challenges in changeover operations lie in properly adjusting the equipment. The largest portion of test run time is due to such 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 the measurements and calibrations in the previous step.

Rationalization of changeover: main stages

The main stages of the changeover improvement process are presented in Fig. 3.2.

Rice. 3.2.

Preliminary stage: 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, the actual conditions in the workplace must be examined very carefully.

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

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

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

The best method is video shooting the entire retooling process. It is extremely effective if the recording is shown to workers immediately after the changeover is completed. Allowing workers to speak often produces surprisingly clear, useful insights into issues. In many cases, this new understanding can be put into practice immediately.

Although many consultants advocate in-depth, continuous analysis of production to improve changeover processes, in fact, informal observation and discussion with workers is often sufficient.

Stage 1: separate internal and external changeover activities

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

If you conduct special research on transferring as many operations as possible from internal to external, then the time of internal operations performed when the equipment is turned off can usually be reduced by 30-50%. Thus, a clear understanding of the differences between internal and external activities is the essence of SMED.

Stage 2: Convert internal activities to external ones

I just noted that typically changeover times can be reduced by 30-50% by separating internal and external procedures. But even this huge reduction is not enough to achieve SMED's goals. At the second stage - converting internal readjustment into external - you need to:

review all transactions to determine if any activities are being misinterpreted as internal; find ways to convert these operations into external ones. This may include, for example, the heating operation, which was previously carried out only after the start of changeover, and the alignment operation, which can be performed before the start of production.

It is often possible to convert an internal changeover into an external changeover by taking a closer look 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 sometimes it is possible to do it in less than ten minutes by simply converting internal actions into external ones, in most cases this is not possible. That is why a focused effort must first be made to simplify all basic internal and external operations. Thus, stage 3 requires a detailed analysis of each elementary operation. The following examples indicate the successful implementation of stages 1, 2 and 3.

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

It is not necessary to perform steps 2 and 3 sequentially; they can be performed almost simultaneously. I have separated them to demonstrate two essential conditions: first analysis, then implementation.

CONCLUSION

The SMED system has been developed over 19 years based on careful analysis of the theoretical and practical aspects of changeover improvement. Thus, analysis and implementation serve as the foundation of a SMED system and should 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 involve separating the two types of activities and converting internal changeover activities to external ones. Once this is done, all aspects of the changeover should be simplified as much as possible. Improvements to the changeover process can be made at any stage.

Chapter from the book "Fast Changeover. Revolutionary Technology for Production Optimization" by Shigeo Shingo, kindly provided by 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 We are constantly developing, trying to improve our products and production. This gives significant competitive advantage, increasing the share of customers and increasing profits. The main task of companies is to reduce material and intangible costs to increase production time, and due to the number of products produced. There are many methods to reduce costs. One of the methods used by companies is the rapid changeover of SMED equipment. The purpose of the work is: Studying the method of rapid equipment changeover.

· Studying theoretical material on this topic

· Analysis of the practical application of the method of rapid equipment changeover

· Formulation of conclusions

Theoretical part

Rapid equipment changeover is a concept for organizing the process of equipment changeover/retooling, which allows you to significantly reduce the time spent on equipment changeover.

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

Assuming that any changeover could be accomplished within 10 minutes, he called his concept SMED.

SMED system is applied

To change the product range,

For quick changeover of production lines,

To reduce production downtime and increase process flexibility.

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

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

· External changeover is part of the changeover process operations that are performed during the manufacture of suitable products on the equipment to be adjusted.

The implementation of the SMED system includes:

Careful study and analysis of actual workplace conditions. The entire changeover process is timed (from the moment the production of product “A” is completed until the production of product “B” begins), all actions are recorded in great detail (picked up, secured, moved, etc.). It is recommended to record the current changeover process on video for ease of subsequent analysis.

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

Convert (where possible) internal changeover activities into external ones. The analysis continues, identifying those actions that can be performed without stopping the equipment (pre-assembly, adjustment, warming up, preparing tools, equipment, etc.)

Simplification and streamlining of all elementary internal and external changeover operations based on their detailed analysis. Developing solutions to eliminate adjustments, settings, performing simplified fixations, organizing parallel execution of work, etc. This step may require changes to the design of tooling and fixtures, which may require significant investments funds. Also developing solutions to improve logistics (delivery of equipment, fixtures, tools, etc.), improve service, reduce movements, etc.

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

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

Thus, through simple logical analysis, even without investing in redesign or fabrication of fixtures (fasteners, etc.), huge potential for improvement can be discovered in any changeover process.

Even carrying out the simplest analysis with 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 requires 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 must be a changeover standard that clearly regulates the sequence of actions, setup and startup parameters, required time and the means for its implementation (tools, equipment, etc.). Of course, the standard for performing changeovers must be supported by managers, i.e. Managers must ensure that nothing prevents compliance with the standard and monitor compliance with it.

Key points to pay attention to when using the described tool:

· Definition of clear goals and required work results. Frequent mistakes - improvement for the sake of improvement, or spending time and money to reduce several hours of work for the adjuster. It is necessary to remember the main purpose of the tool and clearly understand the required result before starting work.

· Training and correct sequential adherence to each step. It is necessary to make sure that the team clearly understands the sequence of steps being performed, and should not skip or shorten any step.

· Standardization of the result completes any improvement. The result must be standardized, and the standard must be 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 sequence of actions when performing changeover, including preparatory work, directly changing equipment (tools).

2.Standardized changeover time.

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

.Reducing and standardizing batch sizes and product inventory levels as a result of increasing the number of changeovers.

Fast changeover provides production flexibility and reduces losses associated with:

· overproduction;

· excess inventories;

· downtime of equipment and operators.

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

Advantages: Reducing equipment downtime, minimizing inventories, focusing on production in small batches or to order, quick adaptation to changes in demand.

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

The frequency and duration of trial runs and adjustments depends on the qualifications of the installation engineer.

Application in practice

The Matsushita Electric division was established in 1956 to produce National brand washing machines. It now produces dishwashers and double-compartment washing machines on a 1,000-meter-long assembly line at a rate of approximately 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 products in 1980. National washing machines are in steady demand not only in Japan, but also in 68 countries around the world.

APPLICATION OF SMED:

.Re-adjustment of lubrication devices. Applying grease is one of many operations on 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.

.Changing dyes for protective coating operations by sintering.

.Reducing mold changeover time. In recent years, the number of washing machine models has increased in line with customer demands, leading 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 minimize changeovers. With this approach, however, as the number of models and components increased, inventory levels increased. Gosei was founded in 1949. Since then, the company has successfully developed and refined a number of high-polymer products for the automotive industry. Toyoda Gosei designs and manufactures plastic, cork, urethane and other parts and has achieved an overwhelming market share in many items, including steering wheels, various hoses and piston plugs. The company's capitalization in 1978 was 3.3 billion yen, billion yen, sales volume was 106.4 billion yen, and the number of employees was 4,600 people. Eight factories produced 12 thousand types of products.

The market situation for the automotive industry was favorable until 1977 - 1978. But after the 1979 oil crisis, declining consumer demand forced manufacturers to expand production of small cars and adjust their policies to improve quality. As competition in the industry intensifies, both in the country and in the world, only prices for 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 founding 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 operate without loss;

· workers and machines perform only those jobs that add value;

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

The goal of these measures, which rest on two cornerstones - just-in-time and worker-assisted automation - is to produce with lowest cost and only those goods that will find sales, 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 a custom manufacturing process, the JIT concept means producing the required number of products at the required 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:

· Re-adjustment of cutters during machining of fittings

· Changes in cold stamping punch changeover operations

Bridgestone Tire Co., Ltd. founded in 1931 in Kurume, Fukuoka Prefecture. It was the first Japanese tire manufacturer with Japanese capital, and its policy was to produce automobile tires at home using domestic technology. In addition to the fact that the company was designed to satisfy the needs of local consumers and provide inexpensive, high-quality tires, it aimed to cover the costs of importing rubber by exporting finished products.

APPLICATION OF SMED:

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

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

Plant directors, service heads, department heads and all interested employees observe the actual implementation of setup operations in the workshop, look for problems, and exchange opinions on methods for solving them. Announcements about demonstration adjustments are posted at workplaces, and record figures are communicated to everyone. Provide education and training to develop the ability to recognize and solve problems. Improvement of changeover 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 manufacturing. The SMED system is based on both theory and many years of experimental practice. It represents 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 results, and it can be applied in any area 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 implementing 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.

operation readjustment cutter control

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

.Productivity Press development team. Production without losses - Quick changeover for workers. - Institute for Comprehensive Strategic Studies, 2009 - 104 p.

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

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 replacement of dies). Essentially, the SMED system is a set of theoretical and practical methods, which allow you to reduce the time of setup and changeover of equipment to ten minutes. The system was originally developed to streamline die changeovers and related equipment changeovers, but the principles of “fast changeover” can be applied to all types of processes.

It took Shigeo Shingo nineteen years to develop the SMED system. While studying equipment 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 actions, that is, operations that are performed after the equipment is stopped. For example, a mold can only be replaced when the press is stopped.
External changeover actions, that is, operations that can be performed while the equipment is running. For example, mold mounting bolts can be selected and sorted while the press is running.

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

One of the first experiences of implementing the SMED system in manufacturing process Toyota proved that the changeover of a large 1000-ton press can be completed not in four hours, as was done previously, but in just three minutes. The speed of equipment changeover plays an important role for any company seeking to build its production process on the principles of “just in time” and production in small batches. Fast changeover for such companies provides the opportunity to quickly change the model range and avoid the accumulation of excess product stocks in the warehouse.

The SMED system is the most effective approach to reduce equipment changeover time. Thanks to this system, you will be able to significantly reduce the number of complex, time-consuming and unproductive actions for reconfiguring equipment, or even get rid of them altogether, which will undoubtedly not only make your work easier personally, but will also make your company more competitive.

Goals of SMED implementation

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

External changeover operations

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

Receive a stamp or tool from the warehouse;
Transportation to the machine;
Select and sort mold mounting bolts
Prepare documents for the shipment

Internal changeover operations

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

Remove the cutter;
Attach the stamp;
Tighten the nut that secures the equipment;
Replace the mold.

Stages of traditional equipment changeover

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

Why do we need timing and video recording:

Determine the most time-consuming and 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 operator workload

Video recording of the changeover:

It’s not a person’s face to film, but what he does – his hands;
Do not stand still, but move along with the adjuster;
When a service technician works with a tool, it is necessary to record 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, you need to use several video cameras. If there is only one video camera, it should follow the most qualified adjuster;
The camera operator must not enter the danger zone

How to reduce operation time?

Determine whether the operation is external or internal;
Determine why an external operation is performed as an internal operation;
Perform all external operations as external;
Re-timing;
Determine the most time-consuming and labor-intensive operations;
Reduce the time of the most time-consuming and labor-intensive operations

Optimizing the transport of parts and tools

How can you reduce the time it takes to complete operations?

Application of checklists;
Conducting functional checks;
Use of auxiliary equipment;
Introduction of parallel operations;
Use of functional clamps;
Mechanization

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

We thank the OMK Press Center for providing this material.

- Who is developing standards for retooling and how is the implementation process going?

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

Before standardizing changeovers, it is necessary to set a specific goal - for example, to reduce the duration of the operation, improve the quality of the operation, stabilize time and quality. Next, the working group, using a certain procedure, forms a standard for changeover. At the same time, the working group must apply means of improvement, which we will discuss below. Then there is a stage of training ordinary employees to work according to the standard. The last thing is control over execution. On this moment The second stage of the “Standardization of Operations” project is underway, within the framework of which standards will be introduced at key operations of production sites.

- How is this implemented in practice?

At section 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, to fasten the equipment, the worker had bolts of different diameters, difficulties with fastening the bolts, etc. The most optimal solution is to place the equipment within walking distance of the operator, to organize the work whenever possible, without the involvement of an overhead crane. In addition, you can use standardized equipment fastening parts. For example, when installing equipment A, one type of bolts and nuts is required, when installing equipment B - another, when installing equipment C - a third. It takes a very long time to find sets of these bolts and nuts, as well as tools. In this case, 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 of fastening pipeline connecting parts (CPF). The simplest thing is to reduce the length of the thread of the mounting bolt. For example, the time to tighten one bolt is 5 minutes, but if there are 20 of these bolts, it turns out to be 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 improvements can be applied during changeovers - eliminating technological and organizational losses.

- By what principle do you select operations to which technological changeover needs to be applied?

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

- How else can you reduce changeover time?

You can reduce the time for changeover as much as possible by investing and purchasing new equipment and accessories, spending millions of rubles. But you can go through standardization - and we try to simplify the procedure as much as possible without huge investments. There is a third option - 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. What we've found is that most people care about what they do. Accordingly, find out from them what shortcomings there are and eliminate them. As a rule, 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 retooling standards?

As intermediate results show, by standardizing changeovers in some key operations, it is possible to reduce the duration by 25-30%, or even more - this means that we can produce more products, and, accordingly, earn more. We described in detail all the operator’s steps, ensured maximum reduction of unnecessary transitions and described the sequence of personnel actions, application the necessary tool, developed measures to increase the productivity of changeovers, etc. As I see it, it is now necessary to launch a procedure for training employees, the process of introducing improvements to working standards, and to achieve consistency in meeting standards in each work shift.

I like

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 allows you to significantly reduce the time spent when changeover of equipment.

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

Further improvement of SMED led to the emergence of the OTED (One-Touch Exchange of Die) concept - the concept of replacing dies in no longer than one minute.

SMED/OTED methods

The SMED/OTED methods are based on what was discovered in the 50s of the 20th 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 while the machine is stopped, 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 a die to and from a storage location.

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

1. Separation of internal and external changeover operations

It is necessary to clearly define which changeover operations must be performed while the machine is stopped and which can be performed while the machine is running.

2. Transformation of internal actions into external ones

The transformation requires a review of operations in order to check whether among the actions classified as internal changeover, there are no ones left that are actually or may be external.

3. Standardize function, not form

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

4. Use of functional clamps or complete removal of fasteners

In practice, the most commonly used fastening device is a bolt, but its use is sometimes very time consuming. For example, a bolt with 15 threads needs to 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 wasted movements. Bolts are not the only fastening method; one-touch fastening methods that use wedges, pins, and latches or springs as gripping devices to simply connect two parts reduce installation time to seconds.

5. Use of additional devices

Some of the delays associated with internal adjustments can be eliminated by using standard fixtures. When a workpiece secured in one fixture is processed, the next workpiece is installed 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 a 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 parallel operations are performed by two people, changeover times are usually reduced by more than half due to the savings in movement. For example, an operation that takes one worker 30 minutes 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 provides amazing time savings. Eliminating adjustments begins with the understanding that setting switches/controls and adjusting are two separate and distinct functions. Adjustments can be eliminated by using a device to accurately determine the correct position of the limit switch/regulator. Then the only necessary operation is to set the switch/regulator. Of course, the best adjustment is no adjustment. For example, adjustment can be eliminated completely when the number of control positions is limited and constant.

8. Mechanization

Mechanization should be considered when all efforts have been made to improve the changeover process in all the ways described above. Mechanization is essential for replacing large fixtures and dies, casting and compression molds. Fastening of any parts can be done using air or oil pressure. However, investments in mechanization should be assessed very carefully. If the changeover time is reduced by previous methods from 2 hours to 3 minutes, mechanization will most likely reduce this time by no more than another minute.

Implementation stages

SMED takes a progressive approach to changeover improvement. In this case, you need to go through 4 stages:

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 the die, are performed while the machine is stopped. This causes unnecessary lengthening of changeovers.

Stage 2

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

Stage 3

Analyze the current changeover process to determine whether any of the internal activities can be converted to external ones. For example, warming up the mold while the machine is still running eliminates the need to warm up the mold while 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 the several hundred improvements to SMED, the most effective have been:

clear separation of internal and external changeovers
if possible, complete conversion of internal adjustment into external
elimination of adjustments
fastening without screws