“Product range is our main difference” Älmhult Blåsippan is located in the heart of Älmhult and looks like a building that usually houses the administration of a commune in Sweden. Three floors, the facade is covered with white plaster, red trim. Signboard on

The second group of principles includes most of the TPS tools used to improve manufacturing processes, the way new products are developed, and services are delivered. This is often referred to as the "philosophy of lean manufacturing". However, as important and effective as these tools and processes are, they are only a tactical aspect of Toyota's approach and can only deliver long-term results when combined with an appropriate company-wide management philosophy.

Principle 2. Organization production process as a continuous stream, which helps to identify problems.

This principle involves the restructuring of the technological process in such a way as to create a continuous flow that effectively provides value addition. At the same time, the time that work in progress is without movement must be reduced to a minimum.

The flow means that the consumer's order is a signal to receive the raw materials that are necessary to fulfill this particular order. Raw materials are immediately delivered to supplying enterprises, where workers produce components that are immediately delivered to the plant. There, workers assemble the product, after which the consumer receives it in finished form. The entire process takes hours or days instead of weeks or months as with mass production. At the same time, work is constantly underway to eliminate losses in this stream.

Unlike mass production, organized according to the principle of specialization (grouping similar works) and releasing goods in batches, one of the main elements of TPS are the so-called "cells" that create flow of single items.

A cell is a collection of people, machines or jobs organized and operating in accordance with the sequence of technological operations. They are created to ensure the flow of single products (services) that one by one undergo various technological operations. The speed of such processing is determined by the needs of the consumer. In practice, the ultimate goal of lean manufacturing is the organization of the flow of one-piece products in relation to all types of work, whether it be design, order taking, or production itself.

Cell formation implies the so-called multi-process system of labor organization, that is, the maintenance by each employee of several machines of various functional purposes (as opposed to a multi-machine system, in which one operator serves the same machines). This allows you to reduce the number of production personnel (that is, increase labor productivity) and at the same time ensure that each employee acquires several qualifications instead of one.

The lean way of organizing production in comparison with the traditional approach is schematically shown in Fig. 22 and 23 on the example of the process of creating computers.

Rice. 22.

Rice. 23.

As you can see, the creation of a flow of single products involves the almost complete abandonment of stocks. According to the Lean philosophy, inventory prevents problems from being identified. Indeed, under the traditional approach, if one of the steps in the process fails, the other steps will proceed as before, as long as there is sufficient inventory. When organizing the flow of single products, in the event of an error in any area, the entire cell stops, and this gives rise to the need immediately eliminate the cause of the failure. Thus. flow is the key to continuous improvement ("kaizen") and development of people.

To characterize the speed of the cell, the concept is introduced "tact", the time of which is determined by the rate of acquisition of products by the consumer.

So, if the working day is 8 hours (480 minutes), 20 days a month, and the consumer purchases 19,200 units of products per month, then 960 units must be produced per day, that is, one product in 30 seconds. With a properly organized one-piece flow, each stage of the process should take 30 seconds. If the work goes faster, it will lead to overproduction, if it goes slower, a bottleneck will appear in the process.

Continuous flow and takt time are most easily applied in batch production of goods or services. However, in principle, these concepts are applicable to any repetitive process, if you list its stages and identify and eliminate waste.

The advantages of such an organization of production include:

• 1) quality embedding- each operator is simultaneously a controller and tries to solve the problem on the spot, without passing it on to the next stage; if he missed defects, they will be found very quickly and the problem will be immediately corrected;
• 2) true flexibility- reducing the lead time of the order allows you to produce what the consumer really needs at this particular moment in time;
• 3) productivity increase- the organization of the cells allows you to immediately see who is overloaded and who is left idle. In this way, it is easy to calculate value-adding work and calculate how many people are required to achieve a given productivity;
• 4) release of space- in the cells, all blocks are fitted to each other, and stocks take up almost no space;
• 5) security enhancement- reducing the number of material movements automatically reduces the number of accidents at work;
• 6) morale boost- employees can quickly see the fruits of their labor, which increases job satisfaction;
• 7) destocking, which leads to a reduction in the cost of storage, physical and obsolescence of materials, reduces the number of defects from excessive loading and transportation operations, and also frees up working capital.

Speaking about the practice of implementing TPS, J. Liker warns business leaders against the following possible mistakes.

• 1) Creating a Pseudo Thread consisting in a simple rearrangement of equipment. By sliding blocks of equipment together, companies create an external semblance of a cell, but at each stage they continue to be mass-produced, without thinking about the takt time, which is determined by the consumer.
• 2) Immediate abandonment of the stream when problems occur. As soon as it becomes clear that the creation of a flow can lead to certain costs, the company abandons the decision. This can happen in any of the following situations:
  • - stopping one of the equipment blocks leads to the termination of the cell;
  • - changeover of one of the equipment blocks takes more time than expected and slows down the operation of the cell as a whole;
  • - you have to invest in a technological operation that was previously carried out at another enterprise in order to produce it on site.

Cell maintenance requires a discipline that is very difficult for many businesses to maintain. However, in the long term, all the troubles and costs are paid off by achieving high results.

Principle 3: Use a "pull" system to avoid overproduction.

One of the fundamental principles of TPS is "pull"

- the ability to design and produce what the customer really needs at the right time and in the right quantity.

This system is an alternative to the "push" that is carried out on most modern enterprises: the goods are produced according to the plan, in batches, and "pushed" to the market for sale.

A true one-piece flow is zero inventory system, which produces goods only when they are needed by the consumer. But since such a flow is almost impossible to create, since it is impossible to achieve the same duration of all operations, as a compromise between the ideal option and pushing, small stocks are created between the stages of the process, the volume of which is strictly controlled.

The concept of pull is based on the principle of operation of American supermarkets. In any supermarket, stocks of goods on the shelves are replenished as they are taken apart by buyers, that is, as they are consumed. In the shop floor, this means that the production or replenishment of parts in Stage 1 should be carried out as the next Stage 2 uses up almost all the stock of parts manufactured in Stage 1 (i.e., only a small spare number of parts remains). In TPS, the next batch of parts from Stage 1 is requested only when the number of parts used in Stage 2 has been reduced to a predetermined minimum. Thus, until the consumer has used a certain product (did not “pull it off the shelf”), it lies in stock and there is no replenishment of the stock. Overproduction does not go beyond a limited number of products, and a close relationship is established between the needs of the consumer and the volume of production.

A special alarm system lets you know that the stock needs to be replenished. In lean manufacturing, it looks extremely simple: empty containers and special cards are used as alerts. If an empty container is returned to you, this is a signal that you need to refill it with a certain number of parts or send a card back with detailed information about the part and its location. This system of work is called "kanban system"at and its purpose - manage material flow, ensuring the smooth operation of the just-in-time system. The functions and rules for using this system are shown in Table 15.

Table 15

Functions and rules for using the Kanban system

• 1 Kanban has many meanings: sign, card, tag, door sign, poster, bulletin board. In a broader sense, it denotes a signal.

Thus, the third principle of lean manufacturing implies that:

the internal consumer who accepts the work gets what he needs, at the right time and in the right quantity. At the same time, the stock of products is replenished only as they are consumed;

• - WIP and stockpiling are kept to a minimum. A small quantity of finished goods is held in stock and replenished as the consumer picks them up;
• - production is sensitive to real daily fluctuations in customer demand, and is not based on a pre-arranged schedule that reflects only the expected demands of customers.

Principle 4. Even distribution of the amount of work (“heijunka”).

As already noted, the main principle of TPS is the elimination of waste (Toyota managers and workers use the term “m#tsa” to refer to them). However, this is only one of the conditions for the success of lean manufacturing. In practice, the enterprise must get rid of the three causes of inefficiency, representing a single system.

• 1) Moo da - activities that do not add value. They include the eight types of losses mentioned above.
• 2) M$ri - overloading people or equipment. Muri forces a machine or a person to work to the limit. The transfer of people threatens their safety and causes quality problems. Overloading equipment leads to accidents and defects.
• 3) M$ra - uneven production schedule, in some way is the result of the first two causes. Causes of unevenness - improper scheduling or fluctuation in production volumes caused by internal problems (downtime, missing parts, etc.) The uneven level of production makes it necessary to match the available resources (equipment, materials, people) with the maximum volume of orders, even if in fact its average level is much lower, and this leads to overproduction - the main type of muda.

"Heijunka" is the alignment of production both in terms of volume and product range To prevent sudden ups and downs, products are not released in the order in which consumers order. First, orders are collected over a period of time, after which they are planned in such a way as to produce the same assortment of products in the same quantity every day.

Consider the leveling system using the example of the production of two types of products - A and B. If there is a flow of single products, you can manufacture them in the order of receipt of orders (for example, A, B, A, B, A, A, B, B, B, A .. .). However, this means that the production will be random. Therefore, if on Monday there are twice as many orders as on Tuesday, then on the first day the staff will have to work overtime, and on the second day they will have to go home before the end of the working day. To align the schedule, you need to find out the consumer's requests (for example, for a week), decide on the nomenclature and volume, and draw up a balanced schedule for each day. Suppose we know that for every five A's, five B's are made. Then we can even out production and produce them in the sequence A, B, A, B, A, B. This is leveled production with mixed stock, since heterogeneous products are produced, but at the same time, based on the demand forecast, a certain sequence of production of different products is built with a balanced level of volume and nomenclature.

Leveling the schedule gives the company the opportunity to:

• - balance the use of labor resources and equipment;
• - balance the orders issued to the previous processes and suppliers (at the previous stage, a stable set of orders is received, which reduces the amount of stocks, and, consequently, costs).

Thus, the use of heijunka eliminates muri and mura and standardizes work, which greatly simplifies the identification of losses of other species.

The production of a variety of products in small batches requires the use of specialized and at the same time easily readjustable machines and production mechanisms, as well as the maximum reduction in their changeover time. That is why Toyota is very careful in choosing equipment. In addition, she trains all her workers in the so-called "quick changeover" technique and constantly works to improve it.

Principle 5. Stop the production process if there are quality problems.

Lean manufacturing assumes that quality should be built into the manufacturing process. It means application of methods of prompt detection of defects and automatic stop of production in case of their detection(system jidoka). Jidoka involves equipping equipment with devices that detect deviations and automatically stop the machine. Such a system

is called "bye-yoke"- error protection. The following examples of its action can be given:

in case of an error in the workflow, the part will not fit the tool;

if a defect is found on the part, the machine will not turn on;

• - in case of an error in the workflow, the machine will not start processing the part;
• - in case of errors in the workflow or omission of one of the operations, corrections are automatically made and processing continues;
• - if one operation is skipped, the next stage will not start.

As for the employees, if any of them noticed a deviation from the standard, he is given the right to press a special button or pull the cord and stop the assembly line. When the equipment stops, flags or indicator lights accompanied by music or an audible alarm signal that assistance is required. This signaling system is called "andon" .

The jidoka system is often referred to as autonomy - endowing the equipment with human intelligence. Autonomization prevents the production of defective products and overproduction, and automatically stops the abnormal course of the production process, allowing you to deal with the situation. This method is much cheaper than checking quality and correcting defects after the fact. In addition, autonomization changes the essence of equipment operation. If the working process proceeds normally, the machine does not need an operator. Human intervention is required only in case of failures in the production process. Therefore, one operator can serve several machines. Thus, thanks to autonomization, the number of employed workers is reduced and the overall efficiency of production is increased. Note that the creator of TPS Taiichi Ohno considers this system one of the two basic principles of lean manufacturing (the other is the just-in-time methodology).

It should be noted that building quality first of all depends on the staff, and then on the technologies used. Employees of the company must take responsibility for quality assurance - this should be decisive in their value system. Technologies are only tools that help to implement the philosophy of quality in practice.

So, the fifth principle of lean manufacturing is described by the following provisions:

• - quality determines the real value of the products;
• — use equipment that can independently recognize problems and stop when they are detected, as well as a visual system for notifying the team leader and team members that a machine or process requires their attention. Jidoka (machines with elements of human intelligence) - the foundation for "embedding" quality;
• - it is necessary to use all available modern methods of quality assurance;

the organization must have a support system ready to promptly resolve problems and take corrective actions;

The technology to stop the process when problems arise should ensure that the required quality is obtained “first time” and become an integral part of the company's production culture.

principle b. Task standardization for continuous improvement.

The basis of flow and pull in TPS is standardization, i.e. use of stable reproducible working methods, which makes it possible to make the result more predictable, increases the coherence of work and the uniformity of output, and facilitates the process of building quality.

Three elements form the basis of the standard of work in lean manufacturing:

• - takt time;
• - sequence of operations;

the amount of inventory a worker must have on hand to complete a given standardized job.

These positions are reflected in sheets of standard operations, which hang above each workplace and are an important means of visual control of the production process.

The Toyota approach involves not only the unification of tasks performed by shop workers, but also the standardization of work processes that are performed by employees and engineering workers. In addition, Toyota applies standards to product development and industrial equipment.

Contrary to the popular belief that standardization makes work mechanical, in lean manufacturing, on the contrary, it empowers workers and is basis for innovation in the workplace. According to the TPS ideology, continuous improvement requires process stabilization, because only after learning how to perform a standard procedure, you can think about improving it. In other words, it is impossible to make improvements in the work that you do every time in a new way.

Thus, the most important task in standardizing processes in lean manufacturing is to find the optimal combination of two components:

• 1) providing employees with a strict procedure that they must adhere to;
• 2) giving them the freedom to innovate, allowing them to be creative in solving complex problems in terms of costs, quality, delivery discipline, etc.

The key to achieving this balance is in a certain approach to the creation of standards.

First of all, standards should be specific enough,

to serve as guidelines for practical activities, but still quite wide. to allow some flexibility. Standards regarding the performance of manual work of a repetitive nature have high level specification. When designing, where there are no fixed quantitative indicators, the standard should be more flexible.

Secondly, the improvement of standards should be done by people who themselves do this work. No one likes to be forced to follow the rules and procedures developed by others. Imposed rules, followed by strict enforcement, lead to friction between management and workers. However, those who are satisfied with their work and understand that they have a chance to improve the procedure for its implementation will fulfill the requirements fixed in the standard without dissatisfaction. At the same time, Toyota's approach involves fixing the accumulated knowledge and best practices in new standards. Thus, the experience accumulated by one employee is transferred to the one who will replace him. And that is why standardization in lean manufacturing is the basis for continuous improvement, innovation and staff development.

Principle 7. Use of visual controls so that no problem goes unnoticed.

In order for employees to easily determine the current state of any process, lean manufacturing uses a number of visual aids, the totality of which forms visual control system.

Visual inspection includes any means of communication used in production that allows you to understand at a glance how work should be done and whether there are deviations from the standard. It may provide for the designation of a place reserved for any objects; an indication of the number of objects that should be installed in this place; a visual description of the standard procedures for performing any work and other types of information important for organizing the flow. In the broadest sense visual control is a set of information of all kinds, provided by the system "just in time" in order to quickly and properly carry out operations and processes. The visual control system ensures the transparency of the working environment and thus minimizes possible losses.

In fact, many of the tools associated with lean manufacturing are visual inspection tools used to identify deviations from the standard and ensure a smooth flow of one-piece products. Examples of such tools are kanban, andon, and standard operations. If there is no kanban card on the container that requires it to be filled, then the container is not in place. A full container without a kanban card is a sign of overproduction. The andon signalizes deviations from standard operating conditions. A diagram of the job's standard procedure is posted so that the best known method of ensuring flow at each job site can be seen at a glance. Noticeable deviations from the standard procedure are indicative of a problem.

The visual control system is closely related to the so-called program« 5S”, widely used in Japanese enterprises. The elements of this program (called seiri, seiton, seiso, seiketsu, and shitsuke in Japanese; Sort, Stabilize, Shine, Standardize, Sustain in English) are listed below.

• 1) Sort(remove unnecessary) - sort objects or information and leave only what is needed, getting rid of unnecessary.
• 2) keep order(order) - "everything has its place, and everything is in its place."
• 3) Keep clean- The cleaning process is often a form of inspection that identifies deviations and factors that can cause an accident and damage quality or equipment.
• 4) Standardize- Develop systems and procedures to maintain and track the first three S's.
• 5) Improve- constantly maintain the workplace in order, implement a continuous process of improvement.
• 5S together provide a continuous process of improving working conditions, as shown in fig. 24.

Rice. 24.

You need to start by sorting out what is in the office or workshop. The sorting process separates what is needed for daily value-added work from what is rarely used or not used at all. Rarely used items are tagged and removed from the work area. Then a permanent place is determined for each part or tool, while all frequently used parts should be at hand. The next item is cleanliness, which must be maintained constantly. The support for the first three S's is standardization. "Improvement" is a team-oriented approach to teaching and sustaining the first four S's. Managers play a crucial role in its implementation and must conduct regular reviews of its implementation.

One example of visualization within the framework of the 5S program is stands for tools. On the place allotted for the tool on the stand, its contour is shown. The outline of the hammer shows where the hammer should be, and if it is not in place, it is immediately visible. Thus, these stands help visualize the standard that determines the location of the tools, and one glance at them is enough to see deviations from this standard.

The controls used in TPS (tags, stands, beeps, etc.) are very simple and often even seem primitive. However, the frequent rejection of the latest information technologies in favor of such tools is not accidental. Toyota believes that when working with a computer, which is usually done alone, the employee loses contact with the team and, more importantly, usually (unless his direct duties require the use of a computer) leaves the area of ​​\u200b\u200bits practical activity. Adequately, however, the problem can only be assessed seeing everything with my own eyes. That is why lean production uses controls that do not replace, but complement a person with sense organs. And the most visible visual tools are right in the workplace, where they can't be overlooked and where, thanks to such tools, hearing, sight or touch tells the employee whether he is meeting the standard or deviating from it.

The need for visualization determines a number of standards for the design of service documentation. Thus, Toyota management imposes a strict requirement on managers at any level, as well as on ordinary employees: to fit their reports and problem-solving projects on one side of a sheet of A3 format (this is the largest sheet that can be sent by fax). As a rule, such a document is a detailed and complete description of a process. It must contain brief description problems, description of the current situation, identification of the root cause of the problem, proposal of alternative solutions, reasoning for choosing one of them, cost-benefit analysis. All this needs to fit on one sheet of paper, using as many numbers and graphs as possible. Over the past few years, there has been a move at Toyota to move towards A4-size reporting, as the company believes that more can be expressed in less. the very core of the problem under study.

Thus, the visual control system used in lean manufacturing implies:

• - the use of simple visual aids to help employees quickly identify the location of deviations from the standard;
• - refusal to use computers, monitors, etc., if they

distract the worker from the zone of his practical activity;

• - the use of visual controls in the workplace, which should help maintain flow and stretch;
• - if possible, reduce the volume of reports (to one sheet), even when it comes to the most important financial decisions.

The results of applying a well-thought-out visual control system are increased productivity, quality and safety of activities, facilitated intra-organizational communication, reduced costs and an overall increase in the transparency of the working environment.

Principle 8. Use of reliable proven technologies.

This principle is revealed in the following provisions:

Technology is designed to help people, not replace them. Before introducing additional hardware, it is often necessary to do the process manually first;

new technologies are often unreliable and difficult to standardize, jeopardizing the flow. Instead of untested technology, it is better to use a known, proven process;

• - before introducing new technology and equipment, tests should be carried out in real-life conditions;
• - it is necessary to reject or change technologies that go against corporate culture, as well as violating the stability, reliability or predictability of processes;
• - with all this, it is necessary to quickly introduce proven technologies that have been tested and make the flow more perfect.

Toyota's approach to the introduction of new technologies is fully consistent with the strategy of "great companies" (according to J. Collins), which we have already described in this manual, namely: a technology is only adopted if it is in line with the lean hedgehog concept (improving one-piece flow management) and its corporate culture.

In the process of acquiring new technologies, Toyota prefers to move slowly, often finding that a particular new technology does not meet the strict requirements of supporting people, process and values, and rejecting it in favor of simpler ones. manual methods. However, the company can serve as a global benchmark for using modern methods to optimize the value-adding process.

New technologies at Toyota are introduced only after pilot testing with the participation of a wide range of specialists representing different functional divisions. Thus, each technology is thoroughly evaluated and tested to confirm its suitability for creating added value. The company carefully analyzes the impact that this innovation can have on existing processes. It is in them that, first of all, the nature of work to create added value is explored, additional opportunities are sought for eliminating losses and leveling the flow. Toyota then uses the pilot site to improve the process with existing equipment, technology, and people. Once the process has been improved as much as possible, the company again asks if the introduction of new technology will lead to further process improvement. If the answer is yes, the new tool is carefully reviewed to determine if it is in conflict with Toyota's philosophy and principles, which suggest that: the value of the human being is greater than the value of the technology;

• - decisions should be made by consensus;
• - the main attention in the process of work should be given to the elimination of losses.

If a technology does not conform to these principles, or there is even the slightest chance that it will adversely affect stability, reliability, or flexibility, Toyota rejects it or delays implementation until such issues are resolved.

If the new technology proves to be acceptable, it is then implemented in a way that ensures continuous flow throughout the manufacturing process and helps workers perform tasks more efficiently within Toyota standards. It means that innovation should not distract people from the work of creating value(i.e. be suitable for use directly at the workplace), and obya- it is necessary to provide visualization of the process.

The described approach applies to all types of technologies, including information technologies. The company sees them as just a tool that exists to support people and processes. To improve the performance of any activity, you must first change the way it is done. Information Technology more often than not, they only reflect the processes existing in the company, and therefore, by themselves, are not able to eliminate losses.

• This technology is also often referred to as a Just In Time (JIT) system.
• The author of the "quick changeover" methodology, which is applicable to almost any equipment or process, is Shigeo Shingo, who, along with Taintm Oio, is considered one of the creators of the Toyota Production System. The principles of Shingo, first tested in Japanese enterprises, are now actively used in many European and American corporations. For more on this, see: Shingo Shigeo. Quick changeover: Revolutionary production optimization technology - M: Alpina Business Books, 2006. - 344 p.
• 2 Initially, the devices were called "baka-yoke" ("fool protection"), but one of their creators, Si-geo Xinyu, noticed that the workers were unhappy with this name. Therefore, later the term was replaced by “poka-yoke (“error protection”), which reflects the logic of the production process, since defects can be caused not only by “foolish” people.
• The word "andon" means "light signal calling for help."
• Taiichi Ohno. Toyota production system. Moving away from mass production. - M.: Institute for Complex Strategic Studies. - 2006. - S. 34.

CREATE ASSOCIATED PROCESS FLOW

IDEAL - A FLOW OF SINGLE PRODUCTS

Taiichi Ohno taught that the ideal is the flow of one-offs. For the correct answer on the school exam put five. The correct answer is the one-piece flow. It turns out that in order to master lean manufacturing, you just need to create a flow of single products. What could be easier? In fact, Ohno taught that creating a one-piece flow is extremely difficult and not always feasible. He said:

In 1947, we arranged the machines in parallel lines, and in some places arranged them with the letter L and tried to put one worker on three or four machines in accordance with the processing sequence. Although it was not about increasing the pace of work or overtime, the workers fought back fiercely. The machine operators did not like that the new layout required them to combine professions ... In addition, other problems were discovered. When it became clear what kind of problems these were, I was able to decide in which direction to move. Although I was young and energetic, I decided not to push for immediate, drastic changes, but to be patient.

Ohno learned to be patient and prudent in reducing waste, and in doing so, always moved towards a flow of one-off products, also called "continuous flow." Products are processed sequentially, waiting times between operations and product paths are kept to a minimum, all of which ensures maximum efficiency. Flow reduces total lead time, speeds up cash flow, and leads to higher quality. However, Ohno understood that the flow of one-piece products is very vulnerable.

Attempts to create a continuous flow lead to the identification of problems that impede the flow. Essentially, to create a flow, account for solve problems, and this leads to a reduction in losses. We often compare production to a ship sailing on a sea full of underwater rocks. A high water level, like a high level of reserves, hides rocks, i.e. problems. But if the water level - stocks go down, the ship can crash in no time, flying into the rocks. Most operations have a lot of pitfalls, and it's only natural that we try to keep enough inventory that hides problems.

Ohno found that if inventory levels were reduced, problems surfaced. People have to solve them, because otherwise the production system will stop. This is fine as long as the problems are not too severe and people are able to optimize the process to prevent the same problems from recurring. In addition, Ohno realized that this requires a minimum level of system stability, otherwise reducing inventory will only lead to a loss of productivity, as we saw in Chapter 4.

Linking two or more processes into a continuous flow makes any problem more acute and needs to be fixed immediately. Connected enterprise-wide flow means that if the problem is not effectively fixed, the all enterprise, and maybe several enterprises. Think about how important the availability of equipment, the availability of labor and material supply, if in the event of any malfunction, thousands of people will be forced to stop work! This happens from time to time at Toyota as well. Since all processes are connected together, a problem with one of the main components in a few hours leads to the shutdown of the entire plant. I

Many organizations believe that such production shutdowns are unacceptable. For those who stopped production, a direct road to the labor exchange. However, Toyota sees this situation as an opportunity to identify weaknesses in the system, overcome the identified shortcomings and strengthen the system as a whole. Such a paradoxical way of thinking baffles those who are used to thinking only about financial results. The Toyota Way suggests that by seeing failures as an opportunity for improvement, long-term results can be significantly improved. The traditional way of thinking, on the contrary, comes from the assumption that success is possible only when there are no failures at all.

So the goal is not to compromise performance. A sensible approach requires you to prepare for flow by eliminating the underlying problems, and then moving forward in a meaningful and purposeful manner, starting with planning and building a problem-solving discipline. As the process improves and its reproducibility progresses, further leveling takes place, in which the control parameters are made even more stringent, which allows the next layer of problems to be identified during the next cycle of continuous improvement.

WHY STREAM?

More often than not, implementation failures stem from the erroneous belief that success is rooted in the application of lean manufacturing tools (such as creating a cell). We often arrange visits to lean factories for our clients, sometimes to Toyota factories, and it is quite interesting to hear what they take away from such excursions. Usually they are impressed by cleanliness, order, discipline, thoroughness and people who are focused on their work. But when they see something that can be immediately applied in their own enterprise, their eyes literally light up.

While on a tour of the lean enterprise one day, someone noticed that there was a small supply locker next to each bin, and the bin leader wrote out supplies as needed. A kanban system was used to restock, say, plastic gloves. Our "industrial tourist" burned with impatience to return to his factory and create a similar system for ordering consumables. Unfortunately, he noticed only one tool and lost sight of the interconnectedness and interdependence of the entire set of elements. To successfully create a lean process, you need to have a good understanding of how a particular tool works to achieve a goal. It is unlikely that an experienced mechanic, repairing a car, will first take the first wrench that comes across, and then start looking for a nut suitable for it. First of all, he will determine the essence of the problem and the measures that will eliminate it, and only then will he select the tools necessary for the work.

And yet, we often see organizations pick up tools before they even think about what's going on. “We're going to implement visual control,” the managers say, as if it's a piece of a puzzle that needs to be put in place. The key to long-term success is a shared effort that includes understanding the underlying principles or concept, an effective strategy that requires the implementation of this concept, a methodology for applying this concept, lean manufacturing tools to implement the chosen method, and an effective approach to measuring the overall result.

We believe it is useful to think about the relationship between unit flow and cost reduction in the context of a larger model, as shown in Figure 1. 5-1. Instead of recklessly trying to create a flow and pull system, stop and think about what goal you want to achieve. This model highlights the relationship between the core principle of lean - identifying and eliminating costs - and the method of achieving this goal - reducing the lot size, which brings closer to the creation of a continuous flow. It is not uncommon to think of continuous flow as the primary goal of building a lean process, but in reality, continuous flow aims to eliminate waste in all areas. operations. The first task is to eliminate losses.

When material and information are in continuous flow, the amount of wastage in the process is reduced. This is true by definition. Significant volume loss will not create a flow of material or information. However, what is happening has a deeper meaning. Maintaining a continuous flow between processes ties them together, and one process becomes dependent on another. This interdependence and the limited amount of buffer stocks make any interference with the flow more serious.

Anyone who has tried to create a flow of one-off products (and this is really not an easy task!), understands that exacerbating problems can be a big advantage ... or cause a huge damage. In the absence of an effective support system, exposing problems is tantamount to a death sentence. This is why lean tools are so important: they can create the structure that will help you achieve success and avoid failure. Lean manufacturing tools contribute to the creation of both support systems and control methods that allow you to adequately respond to identified problems.

LESS IS MORE: REDUCING LOSS THROUGH OVERPRODUCTION CONTROL

Genuine one-piece flow means that each operation produces only what this moment need the next one. If the next operation is suspended for some reason, all previous operations are stopped. It would seem that it can be more unpleasant than stopping. However, the alternative to stopping work is overproduction, where we do more or faster than the next operation needs. Toyota considers overproduction to be the most dangerous of the seven types of waste, as it generates the other six (excess inventory, extra movements, extra processing, latent defects, etc.). This allows you to understand how less can become more (less means fewer parts produced in individual steps of the process, more means more value-added work in the process as a whole). The following is an example of a typical situation of overproduction, which negatively affects the satisfaction of consumer requirements.

Case Study: Controlling Overproduction Improves Operational Availability

Standing in a circle and watching the production line showed that overproduction is extremely common. Stocks of products accumulated along the line - products lay in piles. All the workers were constantly busy, but we noticed that the operators spent much of their time stockpiling surplus products. When there was no work, most operators fiddled with inventory (the result of overproduction). Comparing the cycle time with the takt time showed - and this was not surprising - that the duration of all operations was less than the takt time, which means that the operators had extra time. Because they weren't doing other value-adding tasks, they spent that time overproduction and inventory.

In addition, the observation showed that as a result of overproduction in the next operation (consumer process), additional time is spent on moving and unpacking products that arrive in large quantities, and this creates additional inconvenience. The cycle time of this operation was within takt time, however, due to the additional work of moving and unpacking products, the total time exceeded the takt time, and as a result, this operation could not satisfy the requirements of the customer during the planned working time. In this case, the excess of losses was created by the supplier process, and the negative consequences were detected in the consumer process.

We asked the operators who performed the previous operations to stop and stand without causes, instead of continuing to work despite the fact that the next process is littered with excess material. Of course, the operators felt very uncomfortable, because the authorities inspired them that it was unacceptable to stand and do nothing. The importance of this approach is well understood at Toyota, as it allows everyone to see and understand the scope of the opportunity. When the picture is not blurred violent activity (overproduction), everyone sees how much time is wasted.

When the operators began to work smaller(manufacture fewer parts), the time lost by consumer processes was reduced and they could spend it on promotion performance. The control of overproduction made it possible to significantly increase the overall yield of the process as a whole.

Of course, we were not happy with the fact that the operators were idle - waiting is also a kind of loss. Next, it was necessary to decide how to eliminate additional losses during the performance of these operations and, by combining operations, achieve "full load". The analysis of standardized work helped to solve this problem (an example of such an analysis is described in Chapter 4).

Case Study: Creating an Aircraft Repair Flow at Jacksonville Naval Air Station

Repair work has even greater variability than production. It is possible to understand what the problem is and how long it will take to eliminate it, only after a thorough examination. Therefore, repairs are often seen as a craft job that requires the collective participation of an entire team of specialists. It's like a throwback to the old days when a team of craftsmen gathered around the booth to assemble a Ford Model T.

The US Department of Defense performs a huge amount of work on the repair and modernization of ships, submarines, tanks, weapons systems and aircraft. These are all very large objects. Aircraft repairs almost always need to be done urgently. If a fighter is in a repair hangar, it means that one less aircraft is ready for battle.

The largest facility in Jacksonville, Florida, is an airbase that repairs US Navy aircraft. Aircraft periodically come for overhaul, and some of them also have serious defects that require special treatment. Since it is necessary to fix the aircraft and return it to service as quickly as possible, as soon as it arrives at the base, it is rolled into the hangar and qualified personnel get down to business, disassembling the machine into parts. The aircraft is stripped of its skin, repairs or replacements are made, one part after another is checked, and finally reassembled, after which the aircraft is ready to take off again. There is another incentive to do the work immediately - payment. For the repair of aircraft, the base exposes an hourly bill.

Although aircraft have been repaired at the air base for decades, the need to reduce the time an aircraft spends on the ground has always been very acute. It happens that planes are taken out of production, which leads to a reduction in the fleet. If aircraft stay in the repair hangar for too long, the time to complete scheduled combat missions is reduced. The Naval Air Systems Command is rolling out the Air Speed ​​program to speed up the repair process. aircraft at naval aviation.

Two aircraft were delivered to Jacksonville for repairs - RZ and F18 fighters. Repair work was carried out in different hangars. Hired consultants worked at the base as lean manufacturing experts. They led the lean teams and helped them acquire the knowledge and skills to do so. Independently from each other, the experts analyzed the current situation for RZ and F18 and came to the same conclusions:

Each aircraft was treated as a unique project and no standardized process was followed by the people who repaired it.

The work area around the plane was cluttered with tools and parts that were lying around at random.

Maintenance workers spent an unreasonable amount of time walking around looking for the right tools, parts, and supplies.

After disassembling the aircraft, the parts were put into boxes and sent to storage facilities (for this, for example, an automated storage and transportation system can be used), but when the parts are returned from the warehouse so that the aircraft can be reassembled, a lot of time is spent on disassembling the boxes and finding the right ones. details. Often parts went missing as they were used to repair another aircraft. Repair of several aircraft is carried out simultaneously, and when for some reason (for example, lack of basic parts) work on one of them was suspended, mechanics were transferred to work on another aircraft.

There was a conviction that the arrival of aircraft for repairs was unpredictable and it was impossible to draw up a plan that would ensure a stable, even amount of work.

Value stream mapping revealed a huge amount of wastage in existing processes. Future state maps were developed, where solutions of a single nature were proposed for all aircraft:

The process of disassembly, fault analysis, repair and assembly should be broken down into clear steps.

It is necessary to create a production line for each repair site, each of which must perform a certain type of work.

It is necessary to bring the line operation in line with the takt time. An analysis of the actual data showed that the arrival of aircraft is much more stable than is commonly believed.

A standardized work procedure should be developed for each site. I

To stabilize the process and reduce the amount of non-value-added walking in search of tools and parts, the 5S method should be applied.

It is necessary to create a "stationary station" so that in the event of a suspension of work on one of the aircraft (for example, due to waiting for parts that take a long time to manufacture), the aircraft can be placed in it and not stop the general flow. Management must know the process thoroughly and stop the practice of accepting aircraft at any time. Work in progress should be kept under control, not allowing the number of aircraft to exceed the number of repair sites on production lines (this will be discussed below).

The working area was divided into workplaces. This made it difficult from a technical point of view to move the aircraft from one place to another. At some point, the plane was completely disassembled: the wings and landing gear were removed. The F18 was a new aircraft for the base, and they were able to purchase a rig for it, which was a huge contraption on wheels that allowed the dismantled aircraft to be moved from one repair site to another. However, it was impossible to do this with the RZ fighter, and in this case it was decided to create a “virtual production line”. Repair crews approached the aircraft at set intervals to perform a certain type of work. This meant that they had to take with them the tools and materials needed for the respective operation.

To debug the individual components of the system, several practical kaizen workshops were held. Among them were seminars on 5S, during which the base made a redevelopment of the working area, determined its place for everything and marked standard places. Hands-on workshops on material flow helped develop a more rational approach to aircraft dismantling. Now the parts of the aircraft fit into special boxes, and when they returned from storage, they all lay as they should. Hazardous materials were placed on carts in containers. The stock of all containers, parts and materials was replenished using pull systems on use of available stocks. A slow and complex process of detailed analysis of each operation began to develop procedures for standardized work and to bring the pace of work of each section in line with the takt time.

The RZ fighter is a rather old model, which will soon be withdrawn from service. The Navy decided to reduce the fleet of these aircraft by 50 units, from 200 to 150, with the condition that about 120 of these aircraft were constantly in combat readiness. To ensure the combat readiness of such a number of aircraft, it is necessary to reduce the maintenance time. Since these aircraft have experienced fuel system problems and fatigue due to aging, the need for additional mechanical strength testing makes the repair requirements more stringent, and therefore further complicates the work that has to be done in a very short time. We can say that from the point of view of the Navy, the situation was a crisis, and from the point of view of lean manufacturing, it was an ideal opportunity to demonstrate the importance of eliminating waste.

Prior to the presentation of additional requirements for testing and work, the repair of such a fighter took 247 calendar days. In order to constantly maintain 120 aircraft in combat readiness, it was necessary to reduce the cycle time to 173 days, that is, by 30%.

Lean officially began in April 2004 under the guidance of an experienced consultant 5 . Less than a year later, by February 2005, after value stream mapping and numerous kaizen workshops, the results presented in the table became visible.

It is one thing to set up a process, another thing is to manage it. This skill required a completely different approach to management than the one that today's leaders are used to. It was necessary not only to deal with a variety of tools - 5S, standardized work, problem solving, etc., but also to stop attempts to accept an excess number of aircraft. The last task was one of the most difficult. The basis of the flow concept is a fixed amount of work in progress. The line has a certain number of working sections and a "stationary station", there are no other places for aircraft in the hangar. When the repair of one aircraft is completed and it leaves the hangar, the next one can be accepted.

This contradicted all the guidelines of the leaders and the accepted system of indicators. First, the management was convinced that if the aircraft remained outside the hangar, it would take longer to repair it. The adoption of lean manufacturing has proven just the opposite - the lead time is significantly reduced when working on a fixed number of aircraft. Accept

the next plane is possible only after the place at the beginning of the production line becomes free, and until then it is better to leave the plane outside the hangar. Secondly, it used to happen that the workers were left without work, since all the work on the repair of the aircraft in the hangar was completed. Managers feared this situation, since they were judged by the hours of work of production workers, and it was for these reasons that the hangars were provided with an auxiliary workforce. From time to time, when a new aircraft was received for repair, someone from a higher leadership ordered it to be accepted for repair. Lean consultants had to use all their influence to get the plane out of the hangar. It was a real clash of cultures.

The Navy was amazed at the results. The Jacksonville base soon became a favorite tour destination for Navy personnel, Air Force personnel, Navy aircraft depots, and others who wanted to see true lean manufacturing in action. The airbase has become a role model. The most surprising thing, perhaps, was that the repair of aircraft was carried out on a line resembling an assembly line. Creating a production line with a predetermined takt time allowed for continuous improvement, eliminating waste and ensuring a balanced operation of the line as a whole. Chaos and disorganization began to crowd out control and stability.

STRATEGIES TO CREATE ASSOCIATED PROCESS FLOW

Table 5-1 lists strategies for creating an associated process flow, as well as commonly used primary and secondary tools.

lean manufacturing. Depending on the circumstances, it is possible to apply both those tools that were already used at the stabilization stage, and additional ones. With regard to the named goals and strategies, they are all required.

SINGLE PRODUCT FLOW

The desire to create a one-piece flow - the ideal of flow - has become a kind of "fad", with many companies' attempts to achieve this level ending in failure. Creating a flow of one-piece products is an extremely complex task that requires a finely tuned process and special conditions. Often it is simply impossible to create such a flow, in other cases, before reaching this level, it is necessary to go through many turns of the spiral of continuous improvement.

As an analogy, imagine a line of people passing buckets of water on a fire. Only one bucket is passed from hand to hand at one time. This is how a flow of single items is formed when an item is transferred by one participant in the chain to the hands of another. This requires impeccable coordination of actions of all participants in the chain. Having passed the bucket to his friend further down the chain, the chain member immediately accepts the next bucket from his neighbor on the other side. If the rhythm of the movements of the two participants in the chain is not coordinated, one of them will have to wait for the other, and this is one of the types of losses. It is extremely difficult to achieve perfect coordination of actions, this is possible only with a clearly agreed cycle time. If anyone in the line hesitates a little or makes a mistake, it will unsettle everyone else, and the house will burn down.

On most manufacturing enterprises In single-piece flow systems, a single item is placed between jobs, and thus the slight variation in individual worker cycle time does not create a wait. However, even at this level, the cycle time balance of individual operations must be extremely high. The presence of additional products between operations allows you to work with a higher variation in cycle time at different operations, but this approach leads to an increase in overproduction, which is a waste. This is a real puzzle. Reducing buffer stocks between operations reduces overproduction, but increases losses due to unbalanced work cycles.

Moving along the path of creating lean processes, you should stick to the golden mean. Along with resolving a certain number of urgent problems that cannot be ignored, a means of insurance should be taken care of until the reproducibility of the process allows the stages of the process to be more closely aligned. The spiral model of continuous improvement discussed in this section reproduces this cycle. Step-by-step equalization requires the reduction of buffer stocks throughout the flow, which leads to the identification of progressively smaller problems. This again causes instability, and the spiral makes a new turn, bringing to a new level effective work under harsher conditions.

HINT

When is a problem not a problem?

At Toyota, managers have a responsibility not only to stop work and fix problems, but also to constantly and vigilantly identify potential problems. before how they arose. In a well-oiled lean environment with continuous, connected flow, there are certain signs of possible system failure that serve as "warning indicators" for everyone. The ability to identify problems before they occur allows managers to take proactive remedial action and thus prevent failure. Note: Toyota does not believe that failure is always a bad thing.

In essence, the absence of failures in the system is considered an indicator of excess losses. The inability to predict when and where failure will occur is an indicator of an ill-conceived system.

ESSENTIAL FLOW CRITERIA

As we discussed in the previous chapter, a number of conditions are necessary to create an uninterrupted flow. Usually these criteria are met during the stabilization phase, but we will repeat them again.

The primary task of stabilization is to ensure stable reproducibility, at least during the day. The process must fulfill the requirements of the consumer on a daily basis.

Sustained reproducibility requires stability in resources - people, materials and equipment - and their readiness. Resource readiness failures are a major obstacle to flow creation. It is necessary to use methods that ensure the availability of resources (it is not just about increasing the amount of resources, which increases costs).

An indispensable condition is the reliability of the process and equipment. In the early stages, it's about the bigger issues, like downtime and changeovers, but as the process improves, the smaller ones, like ease of use and ease of use, need to be addressed as well.

The cycle time must match (be equal to) the takt time. If operations have different cycle times, waiting and overproduction occur.

TRAP

Attempting to prematurely create a flow of one-piece products is very risky.

We've seen company representatives come back from lean classes excited by the flow of one-pieces and immediately set to work building cells. However, they soon discovered that the cell was idle most of the time and concluded that lean does not work in the real world. The phenomenon that gave rise to their problems is called "piece through exit." Take the situation where five machines are lined up in a one-piece stream and each machine is faulty 10% of the time, in other words, 90% of the time it is up and running. The time that the cell is in working condition will be:

0.9 5 =0.9 X 0.9 X 0.9 X 0.9 X 0.9=59%!

Solution: Keep several items of work in progress between operations, carefully considering where exactly to provide such a buffer stock. This will increase the time of productive operation of the cell up to 90%.

Case Study: Danger of creating one-piece flow for processes with short cycle times

The transition from traditional "batch and queue" processing methods to material flow has become a fad. With most fashion hobbies, there are extremes that cause negative consequences. In many cases, the “craze” with the flow of one-piece products leads to a decrease in performance indicators. The one-piece flow may not be the best effective method with a short cycle time (30 seconds or less).

The objective of one of the kaizen workshops was to create a flow of one-pieces during an assembly operation. The product was a fitting, the assembly of which took 13 seconds. The takt time, determined taking into account consumer demand, was 5 seconds. The work was distributed among three operators and created

cell (another fad) to transfer the product from operator to operator, which is necessary to create a flow.

A few months later, the site was struggling to keep up with consumer demand, and the operators again began stockpiling batches between operations. As the graph of the ratio of cycles in Fig. 5-2, the cycle time of the operators was not properly balanced.

This imbalance is the main reason why operators deviate from the "no parties" rule. If the operators deviate from the original plan, this clearly indicates the failure of the plan. Unfortunately, usually in such cases, management tries to force subordinates to follow the rules and maintain the flow, instead of stopping and comprehending the flaws in the process. Learn to perceive the deviations made by the operator as a positive phenomenon! Stop, observe, and find the real cause of the problem. Its elimination will benefit the process.

Even if the cycle times are properly balanced and a debugged thread is created, there is another less noticeable problem. Attempts to create a one-piece flow with very short cycle times generate a high waste rate, which is calculated as the ratio of waste to value-added work. That's why it happens: in any workflow there is a certain amount of unavoidable waste, for example, you need to take a part and put it in the place of the next operation. These losses can be minimized, but in the best scenario, one movement will take from half a second to a second (take and put). Suppose the conditions are optimal, and this operation takes

second during the work cycle - half a second to pick up the part, half a second to put it down. We get a second of extra movements during the cycle. If the cycle time is five seconds, one second spent moving material is 20% of the total cycle time! If the operation is carried out in 3 seconds, this figure will exceed 30%. This is a huge percentage of losses. However, such losses are often overlooked, since it is believed that since the material is flowing, and the operators are constantly moving, we have lean manufacturing. As you can see, this is not at all the case.

This operation can be improved by not breaking the work into many different operations in an attempt to create a flow, but by putting two operators on it who will take the part and process it from beginning to end. This will reduce the time by two seconds, resulting in a job completed in 11 seconds (Figure 5-3). The net time spent processing one product is 5.5 seconds (two people working at the same time produce two products every 11 seconds, 11 divided by 2 = 5.5 seconds per unit), which exceeds the takt time by 0.5 seconds. The next step is to reduce other wastage and simplify the operation so that it can be done in 10 seconds or less and a unit can be processed in 5 seconds or less.

In this example, thread creation resulted in a 33% performance decrease (three operations instead of two). In addition, on the scale of the entire value stream, this operation was a small fraction of the total material flow. There was much more scope for creating flow and reducing overall lead time by linking operations in other areas using the pull methods described below.

PULLING

The terms "pull" or "pull system" are often confused with "flow". It should be clear that pull, like flow, is a concept. These two concepts are related but do not mean the same thing. Flow is the state of the material as it moves from one operation to another. The pull determines when material is moved and who (the consumer) dictates that the move is necessary.

Many people don't understand the difference between push and pull methods. Some mistakenly believe that they are engaged pulling as the material continues to flow. However, a stream can exist without being pulled. Pulling differs from pushing in three main ways:

1. Certainty. The presence of a clear agreement between the supplier and the consumer, which sets the limit values ​​for the volume of output, assortment and sequence of release.

2. Fixing. Facilities shared by the two named parties must be assigned to them. This applies to resources, location, storage, containers, etc., as well as the overall timestamp (takt time).

3. Control. Simple control methods with visual alerts and physical restraints as agreed.

In a push system, there is no contract between the supplier and the customer regarding the amount of work to be delivered and the delivery time. The supplier works at his own pace, guided by his own work schedule. The material is then delivered to the consumer, whether or not the consumer requested it. The location of the material is not determined, and it is folded where there is free space. Since there is no certainty of mutual obligations and location, it is impossible to develop a clear method of control, since it is not clear what and how to control.

Of course, part of the situation is controlled by accelerated dispatch, rescheduling and rearrangement of people, but this only creates additional waste and variation. Of course, it can be objected that the terms of the agreement of the parties are determined by the schedule. All processes work according to a single schedule. The timetable can indeed be unified, but this does not ensure coordinated actions.

The pull system is a collection of several elements that support the pull process. The kanban signal is one of the tools used as part of the pull system. Kanban is just a communication method, it can be a card, an empty box, a cart, or some other signal by which the consumer says: "I'm ready for the next portion." In addition, there are other elements, including visual control and standardized work. If these three elements of the pull system are functioning properly, there is a "linking" of the processes of the supplier and the processes of the consumer. The three elements listed determine the parameters of the "binding" and how close and stable this connection is.

The specific situation described below illustrates with an example the three requirements that a pull system must meet. They are most easily illustrated and understood in terms of one-piece flow, but the same principles apply to any variation and in any situation, whether producing a wide range of products in small batches or working in batches where the volume of product between processes is much larger. We took the most understandable example, but these principles are applicable in any conditions.

Case Study: Creating a One-Piece Flow

Operation A supplies parts for Operation B, which supplies parts for Operation C.

Is there a clear contract with specific conditions?

Yes. We said that this is a flow of one-piece products, and this very definition implies specified amount. (As we shall see later, the implied definitions are not enough.)

What are the terms of the agreement?

Delivery of products one by one.

When is the submission?

When is the previous product accepted at the next operation (remember the chain of people with buckets on the fire)?

By observing what is happening, we can determine whether the contract is being fulfilled. On fig. In Figure 5-4, we see that operation B does not fulfill the contract and exceeds the specified limit (one product).

How can you tell if a contract has been violated?

The term "single item flow" implies that there should be no more than one item between operations. THIS IS NOT ENOUGH! The terms of the agreement must be extremely clear and represented in visual, accessible to all form.

What happens if they are not clear and presented visually?

The contract will not be respected, this will cause deviations (generate variation) from the agreed standard (we see that by creating a pull system, we begin to create a structure that supports the next stage - standardization).

How to ensure visibility, which will allow easy to control the situation?

Define place for a single item and to fix him after him. Circle this place with tape or paint so that it can be seen that only one product is allowed here, and provide the designation with an explanatory inscription so that it is as clear as possible (if a square is outlined on the table, an inscription or symbol should be added explaining what this means). square) as shown in Fig. 5-5.

In addition to visual cues, you can limit the physical space so that only one product can fit in the space provided. This technique is especially effective when the parts are oriented vertically and can be inserted into a special recess, thereby controlling the quantity.

One of the main benefits of flow and clear agreement is that now the consequences of problems are made explicit. If, in the example above, the visual controls indicate a constant deviation from the terms of the contract, then another problem has arisen.

Deviation clearly indicates the presence of a hidden problem that needs to be addressed. In such a situation, managers often lament: "They know perfectly well what to do, but we can't get them to work the way they should." Many managers make the mistake of blaming the operator for non-compliance with the rules, when in fact the operator is compensating for a problem that needs to be solved by their actions. Stop and stand in a circle to determine what deficiency the operator is compensating for.

There are usually two reasons for this situation. First, you need to make sure that the terms of the contract are presented visually in a way that is understandable to everyone; secondly, to check if there are additional problems that the operator is forced to bypass.

The main reasons for deviations in the work of the operator are:

1. An imbalance in the cycle time of individual operations, the cause of which may be a normal variation in the amount of work, skill of the operator or the duration of the cycle of the machine. Usually the one who has extra time left deviates from the rules.

2. Periodic downtime due to lack of parts (or fear that parts will run out). Operators leave the work area to take on additional tasks such as bringing in parts or checking their quality. Suspension of work due to equipment failures or defect correction.

3. Intermittent pauses due to difficulty in operating equipment or fixtures, or when performing overly complex operations.

4. Various reasons, such as the desire to create a reserve in order to gain time for changeover, sometimes the operator leaves the line for any reason, goes to lunch or a break on a rotating schedule, and other reasons of this kind.

In some situations, it makes sense to adjust the amount of work in progress depending on the operation. The one-piece flow requires impeccably to balance the duration of operations, which is an extremely difficult task. Imagine an operation, such as deburring an injection molded part, for which variation in working time is common.

Cycle times will vary slightly each time as most of the time we are dealing with manual operations and no one is able to cycle multiple times in the same amount of time (not even Olympic athletes can run the same distance twice). with the same result). This minor variation can cause intermittent failures in the stream. Operators do not like to stand idle, and to compensate for the problem, they begin to build up buffer stocks. Building up buffer stocks is a logical choice to offset insignificant time variations; however, extension volumes should be limited by the standard. In this case, the agreed buffer sizes, compensating for a slight variation in time, should be no more than two or three units of production.

HINT

Benefits of a side view

Often, communication difficulties are caused by the fact that it is difficult for us

- “j/ realize why others do not understand seemingly obvious things. The purpose of a standard terms agreement is to ensure that everyone has a common understanding of these terms. To check how well you succeeded, find a person who is unfamiliar with the work area, show him the standard and ask him to explain the essence of the contract. You will be surprised to see how difficult it is to convey information about the terms of the contract using visual means!

WORKING WITH A COMPLEX FLOW

Looking at a more complex example, we will see that the same concepts are taken as a basis here. In our case, three different product models are produced - 1, 2 and 3 - and we need to provide flexibility that allows us to produce one of these models at any time. Organization Chart

Let's assume that operation C requires the production of model 2. The operator takes one product from a given place between operation B and operation C. Under the terms of the contract, this serves as a signal for operation B: an empty place is a signal, and when the consumer pulls out the product, one should apply to this the next place, i.e., to make a part for model 2. Now the situation corresponds to fig. 5-7.

Operation B then takes part 2 between operations A and B, which prompts operation A to produce the part for model 2. Once completed, operation B replenishes the stock between operation B and operation C. The picture is now as shown in Fig. 5-8.

Of course, this is a simplified model, but all three necessary conditions are met here and their observance is supported by visual means. This basic model is applicable to high-volume or short-range production, as well as inventory management. Its main advantage is the flexibility that allows you to make any model at any time and quickly switch from one model to another.

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Current page: 10 (total book has 29 pages) [accessible reading excerpt: 6 pages]

Combining people and equipment according to the principle of specialization gives rise to another problem: the product that the consumer needs is not tied to one department. To turn into what the consumer needs, it roams through different departments. Design, supply and financing are handled by different departments. Many value streams flow through these departments, so every time a product is transferred to the next department, there is a delay. The one-piece flow assumes that you consistently build all technological operations into a single line, which allows you to complete the customer's order in the shortest possible time.

On fig. Figure 8.1 is a schematic representation of a computer firm consisting of three departments. One department manufactures system units, the second produces monitors and connects them to the system unit, and the third tests finished computers (in fact, many companies and departments are involved in the manufacturing of a computer in the technological chain). With this structure, the transport department considers it appropriate to move a batch of 10 units at a time. Each department spends one minute per unit, so a batch of computers goes through each department in 10 minutes. Without taking into account the time of movement between departments, it will take 30 minutes to manufacture and test the first batch of 10 units. It will take 21 minutes to get the first computer ready for shipping and shipping, despite the fact that it only takes three minutes to add value to the manufacturing process.

In a system created by Ohno, the effectiveness of a particular process or job transport department does not define the ideal lot size. The ideal lot size with a lean approach is unchanged - it's one product. Ohno did not try to optimize the use of people and equipment in isolated departments. The first Toyota factory worked exactly according to the Ford factory method. But that didn't work, because Toyota couldn't compete with Ford in terms of production volume and economies of scale. So Ohno decided to optimize the flow of material so that it could move through the plant faster. This meant the reduction of the party. And to do this, the easiest way was to break down the barriers between departments and instead of islands that specialized in individual operations, create work cells organized by products, not by processes.

On fig. Figure 8.2 shows the same computer manufacturing process organized as a work cell through which a stream of one-off items passes. If Ohno were to undertake this process, he would take the equipment needed to make the system unit from one department, the equipment for making the monitor and the test bench from the testing department from another department, and build a sequential chain from these operations. In other words, he would create a cell for one-piece flow. Then he would make sure that the operators do not create inventory between these three operations. For example, the one who makes the system blocks should not be taken to the production of the next block until the monitor for the previous block is made and until the finished product is created from these two assemblies. In other words, no one should produce more than what is needed immediately. As a result, operators of such a cell produce 10 computers in 12 minutes. In addition, this lean process allows the first working computer to be ready for shipment in just three minutes instead of 21. Those three minutes represent pure value-added time. The flow made it possible to get rid of overproduction and stocks.

Why, with flow, "faster" means "better"

Often it seems to us that speeding up the process leads to lower quality, faster means sloppier. But the flow leads to quite the opposite result - as a rule, the quality increases. On fig. Figures 8.1 and 8.2 show a defective computer whose monitor is crossed out. During the testing phase, it could not be enabled. With the release of a large batch according to the scheme shown in Fig. 8.1, by the time the problem is identified, there will be at least 21 products in operation, and it is possible that all of them will have the same defect. If this is a defect that was made through the fault of the department that produces the system units, then the testing department will know about it only after 21 minutes. On fig. 8.2, when a defect is discovered, there are only two computers with the same defect in operation, and it will take only two minutes to figure out which operation made a mistake. Thus, in the production of large batches, work in progress can lie between individual operations for weeks, and weeks and even months can pass from the moment a defect is made to the moment it is discovered. But the trace will already “cool down”, and it will be almost impossible to identify the cause of the defect.

The same logic chain applies to any technological or business process. If you allow isolated departments to do their work in batches and transfer those batches to other departments, you are guaranteed delays in completing the work. There will be bureaucratic delays, officials will begin to set standards for each department, and many non-value-added positions will be created to track the flow. Projects will spend most of their time waiting for action or decisions. This will lead to confusion and poor quality. Pick the right people who add value, define the sequence of operations and run the project through the created chain, taking care of how to connect their actions, and you will get the pace, productivity and quality you need.

Takt time: single piece flow pulse

In rowing competitions, an important role is played by the helmsman, who sits on the stern and shouts "and one, and one, and one." He coordinates the activities of all rowers, making sure that they act in harmony and row at the same speed. What happens if one of the rowers is faster than the others? That's right, the order is broken, and the boat moves more slowly. Excess force and speed slows down movement.

Something similar happens in any work, whether we are talking about production or the provision of services. If an individual department is over-capacitated, it will overwhelm other departments with mountains of inventory and paperwork, resulting in confusion and slowing down the process. The activities of the departments must be coordinated. How do you determine how fast your one-piece flow cell should run? What should be the capacity of the equipment? How many people will be needed? To do this, you need to determine the takt time.

The German word takt means rhythm or tempo. Takt time is determined by consumer demand - the rate of product acquisition. If the working day is 7 hours 20 minutes (440 minutes), 20 days a month, and the consumer purchases 17,600 units of products per month, then 880 units must be produced per day, that is, one product in 30 seconds. With a properly organized one-piece flow, each stage of the process should take 30 seconds. If the work goes faster, it will lead to overproduction, if it goes slower, a bottleneck will appear in the process. The concept of "tact" is used when it is necessary to determine the pace of production and not allow workers to fall behind it or be in too much of a hurry.

Continuous flow and takt time are most easily applied in batch production of goods or services. However, with a creative approach, these concepts apply to any iterative process, if you list its stages and identify and eliminate waste (see Chapter 21). An example of such a list at a US Navy shipyard is given at the end of this chapter. My colleagues and I have come across many other examples in the course of our work: filling out invoices for the design of ships, screening people by the security service of the Navy shipyard, admitting new members to a professional association, reimbursement of employees, working with applicants for jobs ... You yourself can find many others examples. Of course, the concept of takt time and one-piece flow is most easily applied to repetitive maintenance operations that require a certain amount of per-unit cycle time stability, but the Toyota Way is not about looking for the easy way out.

Benefits of the one-piece flow

Creating a flow of single products involves a broad program of measures to eliminate all kinds of muda (waste). Let's take a closer look at some of the benefits of flow.

1. Embedded quality. The one-piece flow greatly simplifies the build-in of quality. Each operator is also a controller and tries to solve the problem on the spot, without passing it on to the next stage. Even if he missed the defects and they went further, they will be found very quickly and the problem will be immediately identified and corrected.

2. Genuine flexibility. If the equipment becomes part of the production line, our ability to use it for other purposes will be reduced. But the lead time is reduced to the limit, which means that we are more flexible in responding to customer requests, making what he really needs. Instead of waiting weeks for the system to which the order is given to issue products, we can complete the order within a few hours. The transition to a new product range, which is required by changing consumer demand, is carried out almost instantly.

3. Improve performance. When work was divided into departments, you felt like you were maximizing productivity because work efficiency was judged by the workload of people and equipment. It is actually difficult to determine how many people it takes to produce a given number of units in high volume production because productivity is not measured in terms of value-added work. Who knows what the productivity loss is when people are "loaded" with producing surplus parts that then have to be sent to the warehouse? How much time is wasted searching for defective parts and repairing finished products? If there is a one-piece flow cell, non-value-adding work such as moving materials is minimized. You can immediately see who is overloaded and who is left idle. It is very easy to create a cost estimate for value-adding work and calculate how many people are required to achieve a given performance. When it comes to moving a mass-produced supplier to a TPS line, the Toyota Supplier Support Center achieves at least 100% productivity gains in every case.

4. The release of space in the shop. When the equipment is distributed over the areas, significant areas between them disappear, although most of them are occupied by reserves deposits. In a one-piece flow cell, all blocks fit together and inventory takes up almost no space. If the production areas are used more efficiently, the construction of new facilities can be avoided.

5. Increased security. As one of America's first adopters of TPS, Wiremold Corporation has achieved exemplary security performance and has won numerous national security awards. However, when the company decided to take on the challenge of transforming high-volume production into a single-piece flow, it was decided that a special safety improvement program was not needed. The reorganization was led by Art Byrne, a former president of the company, who studied TPS and understood that the flow of one-pieces would automatically lead to improved safety by reducing the amount of material that had to be moved around the plant. Reducing the volume of cargo allows you to get rid of forklifts, which are often the cause of accidents. The volume of containers that need to be lifted and moved will also decrease, which means that the number of accidents when lifting containers will decrease. If you deal with the flow, security increases by itself, even if you do not pay special attention to it.

6. Increased morale. Wiremold's lean organization found that employee morale improves every year. Prior to the transformation, only 60% of employees in surveys said they worked for a good company. This figure has grown every year and in the fourth year of transformation it exceeded 70% (Emilani, 2002). The flow of one-off products leads to the fact that most of the time people are busy creating added value and can quickly see the fruits of their labor, and when they see their successes, they feel satisfaction.

7. Reducing inventory. By not investing in stocks that lie idle, you can use them for something else. At the same time, you will also save on bank interest, which must be paid for funds frozen in stocks. You will also avoid stock obsolescence.

On fig. 8.3 shows a traditional shop, where the equipment is grouped by type. One tool that can be used to schematically represent material paths is the Spaghetti Diagram. If we plot the flow of materials in the shop on a diagram, we get something resembling spaghetti, which are randomly mixed on a plate. The product moves randomly in different directions. The work of individual sections during the movement of the product is not coordinated. No amount of schedules and plans can eliminate the variability inherent in a system in which material moves randomly.

On fig. In Figure 8.4, which shows the lean cell, we see a different picture. Equipment is grouped according to the flow of material as it becomes a finished product. At the same time, the equipment is placed in the shape of the letter U, since such an arrangement contributes to the efficient movement of materials and people and facilitates the exchange of information. You can organize the cell in the form of a straight line or the letter L. In this case, we have shown the trajectory of the movement of two people who serve the cell. What if demand drops by half? Leave one operator per cell. What if demand doubles? Place four people on the cell service. Of course, in order to serve different technological operations, people must be prepared to combine professions, such are the requirements of Toyota factories.

Why is it difficult to create a flow

Do you think that as soon as you create cells for the flow of one-off products, life will immediately improve and all problems and misfortunes will disappear? Do not even hope! If you start thinking in terms of lean, life will become much more difficult for a while, at least until you learn how to constantly improve the process. Taiichi Ohno says:

In 1947, we arranged the machines in parallel lines, and in some places arranged them with the letter L and tried to put one worker on three or four machines in accordance with the technological route. Although it was not about working overtime, the workers fought back fiercely. The machine operators did not like that the new layout required them to combine professions. They did not like the transition from the system "one operator - one machine" to the system "one operator - many machines for various operations." They could be understood. In addition, other problems emerged. When it became clear what kind of problems these were, I was able to decide in which direction to move. Although I was young and energetic, I decided not to push for immediate, radical change, but to be patient (Ohno, 1988).

If, in traditional mass production, one of the process steps fails, for example, it takes a long time to change over a machine, someone is absent from work due to illness, or equipment fails, other “independent” process steps will continue as before, because you have plenty of stock. When you link individual operations, creating a one-piece flow, if a failure occurs in one area, the entire cell stops. Either you swim together, or you all go down together. So why not make your life easier and create a reserve stock? However, any stockpiles - accumulations of material or virtual accumulations of information that are waiting in the wings for a long time - prevent problems and inefficiencies from being identified. Stocks develop the bad habit of sidestepping problems. If you avoid solving problems, you are not improving processes. One-piece flow and continuous improvement (kaizen) go hand in hand! If your competitor decides to take the difficult and thorny path of lean, no amount of inventory will help you, you will face bankruptcy. Minora, former president of Toyota Motor Manufacturing and student of Taiichi Ohno, says:

Someone who has started production on a one-piece flow system fails to keep the desired number of products, so at first everyone is discouraged and does not know what to do. But it makes people think: how can you get the right amount? This is the essence of TPS, we can say that we deliberately confuse people so that they are forced to change their approach to the problem.

Many companies I've visited have made one of two mistakes when implementing flow. The first was that the stream was not real. The second mistake was to immediately abandon the flow as soon as problems arose.

An example of a pseudo-flow was a hardware swap. By sliding blocks of equipment together, the company created an external semblance of a cell for the flow of one-off products, but at each stage continued to be engaged in mass production, without thinking about the takt time, which is determined by the consumer. It looked like a cell for the flow of products, but the work went on in the old fashioned way, according to the principle of mass production.

The Will-Burt Company in Orville, Ohio makes various products from billet steel. One product that is produced in high volume is a family of telescopic steel masts that are used in radar vans or film crews. Each mast has its own characteristics depending on the application, so all products are different. This company called the process of making masts a cell and believed that they had created lean manufacturing. When I, as a lean consultant, helped organize the process review, the production manager warned us that the inventory of parts was so diverse that we were unlikely to improve the existing flow.

During the week-long kaizen workshop, the current situation was analyzed, and it turned out that we are dealing with a classic pseudo-flow. The time required to create one mast (value-added processing time) was 431 minutes. However, the pieces of equipment that were used to manufacture each mast were located so far apart that large pallets of mast had to be moved with forklifts from one workplace to another. Each workplace was stocked with work in progress. The total lead time from raw material to finished product, taking into account the length of stay in the state of incompleteness, was 37.8 days. Most of this time was occupied by the storage of tubular blanks and finished products. In terms of processing time at the factory, the job, which took 431 minutes, from sawing to the final stage - welding - took four days. Moving within the plant, each mast covered a distance of 1792 feet (546 meters. - Approx. scientific ed.). To solve these problems, it was proposed to place equipment blocks closer to each other, handle products one by one, refuse to use a forklift between operations (to move products between operations that could not be carried out side by side, a special trolley was designed, the height of which appropriate for the workplace). In addition, it was proposed to issue a separate work order for each mast instead of a set of work orders for a set of masts. The result of these changes was a significant reduction in lead times (see Figure 8.5), reduced inventory, and saved production space.

Among other things, it was checked how long it takes to place a work order, and this allowed to get an additional positive effect by eliminating the old method. The accumulation of batches of work orders generated a lot of losses; and when such a system was ended, the time was reduced from 207 minutes to 13 minutes. On fig. Figure 8.6 shows the flow before and after the week-long kaizen workshop. It can be seen that the “before” situation is actually a pseudo-flow. The pieces of equipment seem to be located side by side, but there is really nothing like a flow of one-off products. The people working in the plant did not fully understand what flow was and did not realize that they were dealing with a pseudo-flow. The “after” situation improved qualitatively, which surprised and delighted everyone in the company. They were shocked that this was done in just a week.

The second mistake that those who implement the flow make is the abandonment of the chosen course. As soon as it becomes clear that the creation of a flow can lead to certain costs, the company abandons the decision. This can happen in any of the following situations:

Stopping one of the equipment blocks leads to the fact that the entire cell stops working.

Reconfiguring one piece of equipment takes longer than expected and slows down the cell as a whole as production comes to a halt.

When creating a flow, you have to invest in a technological operation that was previously carried out in another enterprise (for example, heat treatment) in order to produce it on site.

I've seen companies drop flow in cases like this. They thought flow was great as long as the benefits of batch size reduction and the flow system were shown to you in a theoretical model. But it is far from being so good when we try it in action, and we see that it immediately causes all sorts of troubles and costs. Once a one-piece flow cell is created, maintaining it requires discipline, which is impossible for many manufacturing companies because they do not fully realize the complexities and challenges of continuous improvement. However, in the long run, these annoyances and short-term costs will certainly pay off, leading to amazing results.

In any process, Toyota strives to create a true one-off flow by eliminating waste, as stated in Principle 2: A continuous flow process helps identify problems. To create a flow means to link together operations that were previously separated. When such a connection is established, the team works more smoothly, the system responds quickly to quality problems, the process becomes manageable, and immediate problem solving becomes a pressing need, forcing people to think and develop. Ultimately, for the Toyota approach, the main benefit of one-piece flow is that it forces people to think and improve.

Emphasizing the need to think, Toyota stands for the name of its production system, TPS, as "Thinking Production System" ("Thinking Production System"). For the sake of identifying problems, Toyota is ready to stop production, knowing that this will force the team members to find a solution. Stocks hide problems and allow you to postpone their solution indefinitely. With Toyota's approach, the problem is solved as soon as it is discovered. Chapter 11 (on jidoka) talks about this in more detail.

Case Study: Describing Processes at a Navy Ship Repair Plant

An excellent example of how one-piece flow can be applied to a repair shop is the Navy Shipyard in Puget Sound. Here they began to use the flow of single products in the fall of 2001. The plant is not engaged in construction, but in the repair of Navy ships - from submarines to aircraft carriers. The repair of each ship is unique, so the work is carried out in close contact with engineers who diagnose the problem and set the task for the upcoming repair work. The technical documentation, including instructions for performing the work, is folded into a folder that is transferred to the factory so that qualified workers can carry out the appropriate repairs. As a result, mechanics had to deal with permits, funding, and other paperwork to get the job done. The instruction folder often became a bottleneck in the planning process and led to additional costs.

To improve the process, a week-long kaizen workshop was held. It was preceded by thorough preparation. Preparations were underway for the reorganization, in the office a room was allocated for a cross-functional cell, which was supposed to deal with production tasks. The workshop focused on mapping the existing process and developing a new process. A step by step review of the process identified wastage including rework, redundant systems, various media (e.g. summary sheets), waiting on forms, checking, unnecessary checks and approvals, poor filing system, lack of required reference materials, unnecessary walking, waiting and information incompleteness.

As a solution, it was proposed to develop a cross-functional cell to collect all work instructions together. As a result, handovers have been reduced and non-value-adding transactions have been eliminated. Taking into account the need for work instructions (these needs are very easy to predict) and the time required to develop them, the takt time was determined. The most important was the selection of employees who do the bulk of the work, and the removal of barriers that separated them. The cell was set up in the office, and a folder of work instructions was transferred from one position to another in record time. Previously, in the office, employees were grouped according to their functions, and the rooms were separated by high partitions so that everyone had their own office. Now, with the presence of a cell, the tables of leading experts were located around a round table. Production tasks were passed along the table from one specialist to another, forming a stream of single objects. The timing of the time spent on creating added value before and after the transformation showed amazing results. Note that some time wasted on non-value-adding processes is unavoidable, such as filling out a number of paperwork in accordance with the Navy regulations, although these paperwork is not always necessary for the work of mechanics. We have presented such time costs in a separate column, separate from the "waiting time", which is a waste in its purest form. The results of the reorganization are shown in fig. 8.7.

Principle 3: Use the pull system to avoid overproduction

The more inventory a company has... the less hope it will have what it needs.

Taiichi Ohno

Imagine that you have learned about a wonderful online ordering service. Now all dairy products will be brought to your home, and even with a good discount. There is only one difficulty - you need to determine the number of products for the week in advance. The company can only guarantee one thing - delivery within a week. The company asks you to decide on the order in advance, because it needs to know how much and what products need to be shipped from the warehouse. This will allow her to sell all the products received. Products will be left on your porch in a special refrigerator container. You count how many eggs, milk and butter you usually consume in a week. But you don't know what day they'll be picked up. It might be Monday, or it might be Friday. Therefore, you have to keep a reserve supply of food in the refrigerator. If groceries arrive on Monday and you already have a week's supply of dairy products in your fridge, you have a hard time finding room for new ones. You buy another refrigerator and put it in the garage. If you go on vacation and forget to cancel a week's order, when you return, you will find a container with a week's supply of spoiled food on the porch.

This is an example of a stock push system. Wholesalers often push goods and services into retailers, whether or not the retailer can sell them. The retailer, in turn, pushes goods and services to you without asking if you need them now or not. As a result, you accumulate an excess amount of inventory that you do not currently need, and the retailer himself is also forced to hold huge stocks.

Now imagine that the mentioned Internet service, having received many complaints, decided to improve the service system. They sent you a special transmitter that has a button for each of the products you need. When you open a new bottle of milk or a carton of eggs, you press the corresponding button. The next day, exactly as many products as you unpacked will be delivered to you. As a result, you will have one printed package plus one more. Stocks will be, but very small. If you know you're going to need a lot of milk, you can just go online or call and you'll get what you need immediately. The company itself revised agreements with suppliers of dairy products. If consumers order a lot of products, the company informs the suppliers, and they bring products in quantities that do not exceed the required. This is an example of a "pull" system. You get what you need, when you need it, and the retailer orders products based on consumer demand. I guess you'd be willing to pay a little more for on-demand service to avoid being pushed out.