Many companies achieve the greatest savings by switching from batch production to single-piece flow. Unit flow is a system in which items, materials, invoices, services are processed in order and one at a time as they are received. Sometimes such a production system may be unprofitable or physically impossible. When it is not possible to avoid producing in batches, it is necessary to strive to reduce their size to a minimum. Why is it recommended to work with single items and reduce batch sizes?

1. When production operates in batches, significant amounts of work in progress and material inventories are frozen. cash, which can be used in circulation;
2. When storing and moving batches, as well as while waiting for processing, products and materials are often damaged and become unusable. This leads to additional production costs;
3. When producing in batches, if an error or defect occurs, the entire batch produced is often subject to replacement until the cause of the defect is identified and eliminated. This leads to financial losses and delays in delivery of products to customers.

In contrast to the above, one-piece flow allows:

1. In production, free up significant cash by increasing inventory turnover;
2. Do not store excess inventory in the warehouse and between processing stages, which avoids damage during storage;
3. Transfer one product at a time from one stage to another, which minimizes the risk of damage to the product during transportation;
4. Single piece flow works well with quality control during production and the use of inspection fixtures for each product as it moves through the process. This allows for almost complete control of products, without increasing the cost of such control compared to selective control during production in batches.

The flow of single products involves building pull production. Creating a pull manufacturing system means that items are not passed on to the next stage before they are needed. Implementing a pull and one-piece flow system will help uncover potential bottlenecks in the production process that hinder lean manufacturing. Often, such bottlenecks are large, expensive and high-performance machines that require a lot of changeover time and, as a result, work in large batches. Elimination of such bottlenecks is possible using the method

Unit flow

The traditional approach to constructing flows for manufacturing parts (assemblies):

Equipment is concentrated by type of processing.

Operators are assigned to the types of operations performed (without taking into account the actual load).

What does this lead to?

The work is carried out in batches.

Extra transportation.

Irrational use of operators.

If a discrepancy occurs, the entire batch is rejected.

No flow.

Difficulties in understanding and managing the process.

Long process time.

Narrow specialization of personnel.

Low labor productivity.

Interoperable inventories, inventories finished products.

The need for repeated quality control.

Extra equipment.

Prerequisites for creating a Flow of single items -

reducing costs (expenses) through eliminating losses throughout the entire production process.

Unit flow one of the ways to build production and eliminate losses.

Criteria for constructing the Flow of single products

1. Correct sequence of operations

When constructing a flow of single products, equipment (assembly tables) must be placed sequentially, in the order of technological processing (assembly).

Why is it important?

“visibility” of the flow from a management point of view.

Eliminates unnecessary movements and intersections of operators.

It is easy to understand how the part moves in the flow.

Example building a single flow with a violation of the sequence of operations

This method of constructing a flow has a number of disadvantages:

isolation of operators from each other and, as a result, if problems arise for one of them, the rest will continue their work;

difficulty in rebalancing when changing the production program, and as a result, low productivity of operators;

It is impossible to organize a system for transferring parts between machines using slides, since this will lead to blocking the flow and because of this, the operator will be forced to carry the part on his hands, which will lead to losses such as double touching of the part.

2. U-shape

Equipment and tables are arranged in a U-shaped bracket, maintaining the technological sequence and norms of distance between equipment.

Disadvantages of I-type and L-type unit flows:

each operator can work separately;

During the transition to the beginning of the cycle, the operator does not add value to the product.

The U-shaped flow structure allows you to reduce the time it takes for operators to move in a cell: the operator can work not sequentially with technological operations (example 2, 3), but combine operations that are opposite each other (example 1).

The U-view allows you to place the first and last operations side by side and organize the work in the cell in such a way that one operator controls the entry and exit to the cell. If there is no collection of finished products from the cell, then the operator will not launch a new part into the flow.

3. It is advisable to organize the entrance and exit of the flow into technological passages. This will ensure good supply of workpieces and collection of finished products, good visual control of flows.

4. Counterclockwise flow

The counterclockwise flow movement was chosen due to the fact that the person’s working hand is right and this allows the operator to put more load on his right hand when moving the product. In cases where it is impossible to set the flow counterclockwise (for example: the integrity of the flow is violated when integrating subcollections into the main flow, capital costs are required for modernization and modification of equipment), it is allowed to set the flow clockwise. But this should be the exception to the rule rather than the rule.

5. Customer orientation

Unlike batch production unit flow is based on the concept of takt time, that is, products come out of the flow one at a time once during the takt time for a specific Customer. In this case, the load of the first operator, who controls the input and output, should be close to the takt time, since this operator will set the rhythm of production of the entire cell and will not allow overproduction.

Flaws:

overproduction;

lack of motivation to make improvements.

Advantages:

No overproduction;

Motivation for change.

Flaws:

one operator has low workload.

The low workload of the third operator motivates the department head to set tasks for the site staff to continue work related to improvements. The target state, in this case, will be work by two operators. To do this, it is necessary to analyze once again the work of each operator, eliminate losses in the cycle of each of them and carry out additional loading.

If there is only one operator working in a cell and it is impossible to bring his workload up to the takt time, then how can one ensure the operation of the section according to the takt time? In this case, the operator can work on one or more threads, according to the takt time of each part.

In the case of producing parts on one flow for several customers, it is necessary to work out the possibility of dividing the flows for each of them. Otherwise, stopping one of them will lead to an increase in inventories and the inability to quickly organize new standardized work for the required number of operators on the flow.

Example

Manufacturing flow of 3 parts (common personnel, common machine park):
Part A – two customers (2 points of consumption), part B – one customer.

Building independent flows for each customer

6. Respect for the operator (work safety)

The operator creates value on the production site, but does not create the working conditions for himself. The manager’s task is to create conditions that would allow the operator to work with the least losses, therefore, when constructing the flow of single products, it is necessary to take into account:.

Transfer of parts between equipment at the same level (the machines need to be aligned in height).

No difference in floor heights (production of ladders).

There are no obstacles in the way of the operator’s movement (sharp corners, protruding elements of shelving, tables, slides, control panels, etc.), that is, the operator must use the machine, and not vice versa.

7. Minimum process time

Process time is the time it takes a product to pass from raw materials to the finished product through all stages of processing, including waiting when stored in the form of inventory, both between operations and in the warehouse.

With the traditional method of placing equipment, parts are processed in batches. With this production method, the process time will be the sum of the batch processing time in all operations and transportation time.

The construction of a single flow allows you to eliminate transportation, process and transfer parts between operations and operators one piece at a time (the machines are located close to each other). The process time in a single flow will be the sum of the processing time of one part for all operations.

8. Transfer of parts between operators 1 piece at a time

When constructing a unit flow, you need to consider a system for transferring parts between equipment, which should ensure the operation of the cell in a unit flow. Otherwise, operators will be able to create interoperable inventories.

The main line of thinking when organizing the transfer of parts is not any mechanisms using electricity, compressed air, etc., only due to gravity.

9. Minimum amount of labor

One-piece flow allows for flexibility in the use of labor. Operators are located inside the cell and when the production program changes, it is possible to rebalance the work within the cell without re-planning by adding or removing one or more people.

The flow has a U-shape, but is built in the form of separate islands for specific operators. When changing the production program with such an arrangement of equipment, it is impossible to correctly rebalance and the number of required personnel will not be optimal.

It is recommended to arrange flows for parts that are part of one unit and have the same takt time into a united cell. This will allow you to use the least amount of labor.

In a combined cell of 2 or more parts, the supply of the workpiece and the collection of the finished product must be organized on one side with access to the driveway.

Example. Flow for constructing a single flow, in which there is joint processing of 2 parts

An important point when creating flows of single products is the integration of sub-collections into the main flow, as this allows you to effectively use labor force, reduce interoperational inventories.

When constructing flows of individual products, one of the key points is the correct placement of hydraulic power stations and electrical cabinets. They should be taken out and placed behind the equipment, since their dimensions cause additional time for the operator to move. For example, in machining, all operator actions are non-value-added work and therefore need to be reduced.

10. Minimum amount of equipment

When constructing a flow of single products, the calculation of the required number of pieces of equipment must be carried out based on the business plan. Duplicate equipment, like excess capacity, allows problems to be hidden and therefore needs to be removed from the process. To determine the required amount of equipment, you must fill out a capacity sheet.

If, when executing a program for a particular month, additional equipment that is located in the cell is not required, but is necessary based on their business plan for the year, it must be turned off. One-piece flow helps highlight problems and respond quickly to them.

Equipment with low productivity should be placed at the bend of the cell

When constructing a flow of single products, it is recommended to place equipment with low productivity at the bend of the cell to ensure the same distances when the operator moves each cycle.

When organizing standardized work for operators, low-productivity equipment cannot be divided among several operators. One person must operate such equipment. This will allow you to organize good standardized work and eliminate the overlap of operators.

11. Single washing machines

On flows where the technology provides for washing parts and a common large washing machine is used, it is necessary to develop a washing machine for one part and integrate it into a single flow.

What are the benefits of one piece flow?

1. Product release by takt time:

meeting customer requirements;

allows you to standardize the work of operators;

allows you to set up a pulling system for supplying materials both “into” and “out” of the flow;

allows you to standardize the work of transporters assigned to the flow.

2. Increased security.

3. Quality improvement:

highlights problems, subject to production analysis, with tracking of hourly output (production analysis board);

makes it much easier to embed 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.

4. Improved productivity:

Non-value-adding work is minimized;

minimum strength production personnel.

5. Reduces the process time.

6. Allows for production flexibility:

it’s easy to rebalance if the daily task changes;

wide specialization and interchangeability of operators.

7. Makes production visual:

facilitates control over compliance with the technical process;

helps reduce downtime.

8. Does not reduce stock finished products(work in progress - WIP) within the flow.

9. Allows you to free up occupied space due to more compact placement and removal of duplicate equipment from production.

10. Increased morale. The flow of one-off products means that most of the time, operators are busy creating added value and can quickly see the fruits of their labor, and seeing success, they feel satisfied.

What needs to be prepared to build a flow of single items?

1. Provide stability equipment operation:

organize accounting of equipment downtime;

carry out inspections of machines and necessary repairs;

ensure that there are no oil or coolant leaks.

2. Align the equipment in height (according to the working areas of the equipment) to facilitate the work of operators.

3. Organize a system of forced tool replacement:

determine the frequency for each type;

bring the multiplicity of replacement intervals to the optimal value by changing the standard resistance or using another tool;

organize a pulling system for delivering tools to workplaces.

4. Organize a quality control system, develop measures for the implementation of built-in quality.

5. Work out the possibility of reducing the supply batches of blanks and finished products.

6. Organize work to create a single sink (if necessary) that meets all the necessary criteria.

Stages of building a Flow of single items

1. Carry out standardized work on the stream with the current arrangement of equipment.

2. Fill in the sheet of production capacity of the equipment, which will allow you to understand what reserves are on the stream. If there is excess equipment, it must be excluded from the flow (turn off):

Determine cyclic work (organize it if necessary).

Determine the required standard backlog.

Carry out timing and fill out standardized work forms.

Analysis of the current state and identification of losses based on the timing and completed forms.

Conducting experiments and implementing improvements.

It is necessary to understand that before building a single stream, it is necessary to make improvements and standardize the operator’s work on the existing stream, since there is no point in suffering losses.

Reduced oscillation time.

Improvement work must begin with solving problems associated with fluctuations in operator cycle time and stabilizing the process, since fluctuations are an element of instability that leads to process stops.

Drawing up a strategy to reduce cycle time and increase operator workload.

Training operators for new standardized work and stabilizing the process.

At this stage, the participation of the foreman is very important, as he will help to practice working techniques after implementing the changes.

3. Construct a layout of the target state on paper (U-shaped cell).

4. Consider the material supply system.

5. Prepare for the redevelopment of the flow (creating a stock of finished parts, designing and manufacturing ladders, slides for supplying and discharging materials, etc., manufacturing technological equipment) with the provision necessary conditions to build a unit flow.

6. Carry out redevelopment on the site.

7. Put a single thread into operation.

8. Train operators in new standardized work.

9. Stabilize the process:

analysis and identification of losses;

Implementation of improvements aimed at reducing operator hesitation and cycle times.

10. Ensure receipt of operational information on the flow:

organize the maintenance of a production analysis board by placing it at the outlet of the flow;

organize tracking of daily operational information (fulfillment of production tasks, quality information broken down by type of defect, information on downtime indicating the culprits and downtime).

11. Start solving problems that interfere with the smooth operation of a single stream.

12. Carry out standardized work on the flow and draw up a working standard.

13. Visualize necessary information according to the flow (cards of standardized work, working standards, operational information stand, schedules of preventive maintenance of equipment, etc.).

Production compression

The construction of flows of single products leads to a reduction in the occupied production space. Free islands appear, but there is no flow integrity. This aims to create a continuous flow, that is, bringing production closer to the Customer.

When creating planning solutions, the following approach is used

In accordance with the approach of the Lean Production philosophy, loss analysis begins with an assessment of the losses of the entire flow from beginning to end. Its compression is carried out on individual parts. This approach can lead to irrational technological decisions when forming a flow or additional work for reinstallation of equipment. Therefore, Value Stream Mapping as a tool for production compression is not acceptable.

As noted in the first part of the article, any production planning technique that limits the level of operational backlog will create a so-called logistics pull.

It is customary to distinguish five basic types of “pulling” logistics systems Pull Scheduling:

• replenishment of the “supermarket” (Supermarket Replenishment);
• limited FIFO queues (Capped FIFO Lanes);
• Drum Buffer Rope method;
• work in progress limit (WIP Cap);
• method of calculated priorities (Priority Sequenced Lanes).

We have already examined two of them in detail in the first part of the article.

The “pull” logistics system usually refers to the “supermarket” replenishment system developed in Japan back in the middle of the last century. It is associated with a kind of “locomotive” pulling carriages behind it (that is, with such an organization of material flows when one consumer sequentially pulls deliveries carried out by previous links of suppliers included in the overall chain). But, as we saw in the example of the FIFO limited queue method, in production logistics, a “pull” logistics scheme at the production organization level also means a situation where a work plan drawn up for only one production unit automatically generates operational work plans for all other included ones. into the technological chain of sections. This is the same "locomotive", but here it is no longer required that it be placed in front of the entire train!

Both the logistics replenishment scheme of the "supermarket" and limited FIFO queues can be used quite successfully in mass and large-scale production, where the output volume is quite high and the technological process is constant for the entire family of manufactured products.

How successfully this logistical "locomotive" copes with the tasks of management in custom production (that is, small-scale and single type), we will consider in this article.

Drum-buffer-rope (DBR) method

The Drum-Buffer-Rope (DBR) method is one of the original variants of the “push” logistics system developed in TOC (Theory of Constraints) - the theory of constraints. It is very similar to the FIFO limit queue system, except that it does not limit the inventory in individual FIFO queues.

Instead, an overall inventory limit is set between a single scheduling point and a resource that limits the performance of the entire system, the ROP (in the example shown in Figure 1, the ROP is site 3). Each time the ROP completes one unit of work, the scheduling point can release another unit of work into production. This is called a rope in this logistics scheme. “Rope” is a mechanism for controlling the restriction against overload of the ROP. Essentially, it is a material issue schedule that prevents work from entering the system at a faster rate than it can be processed in the ROP. The rope concept is used to prevent WIP at most points in the system (except for critical points protected by planned buffers).

Since the ROP dictates the rhythm of the entire production system, the schedule for its work is called the “drum” (Drum). In the DBR method Special attention It is the performance-limiting resource that is given, since it determines the maximum possible output of the entire production system as a whole, since the system cannot produce more than its least powerful resource. The inventory limit and the time resource of the equipment (the time of its effective use) are distributed so that the ROP can always start on time new job. In the method under consideration, it is called a buffer. "Buffer" and "rope" create conditions that prevent underloading or overloading the ROP.

Note that in the "pull" DBR logistics system, the buffers created before the ROP are temporary, not material.

A time buffer is a reserve of time provided to protect the scheduled start time of processing, taking into account the variability in the arrival at the ROP of a particular job. For example, if the EPR schedule requires that a specific job in Area 3 begin on a Tuesday, then material for that job must be issued early enough so that all pre-EPR processing steps (Areas 1 and 2) are completed on Monday (i.e., in one full workday). day before the required date). Buffer time serves to protect the most valuable resource from downtime, since the loss of time on this resource is equivalent to a permanent loss in the final result of the entire system. The receipt of materials and production tasks can be carried out on the basis of filling the “supermarket” cells. The transfer of parts to subsequent processing stages after they have passed through the ROP is no longer limited by FIFO, since the productivity of the corresponding processes is obviously higher.

It should be noted that only critical points in the production chain are protected by buffers (Fig. 2). These critical points are:

• the resource itself with limited productivity (section 3);
• any subsequent step in the process where the part machined by the bounding resource is assembled with other parts;
• shipment of finished products containing parts machined by the limiting resource.

Since the DBR method concentrates the protection against possible deviations in the most critical places of the production chain and eliminates everything else, the production cycle time can be reduced sometimes by 50% or more without compromising the reliability in meeting the deadlines for shipping products to customers. Of course, in the DBR logistics scheme, EPR requires constant dispatch control (Fig. 3).

The DBR algorithm is a generalization of the well-known OPT method, which many experts call the electronic embodiment of the Japanese “kanban” method, although in fact there is a significant difference between the logistic schemes for replenishing “supermarket” cells and the “drum-buffer-rope” method, as we have already seen. .

The disadvantage of the “drum-buffer-rope” (DBR) method is the requirement for the existence of a ROP localized at a given planning horizon (at the interval of calculating the schedule for the work being performed), which is only possible in the conditions of serial and large-scale production. However, for small-scale and single-unit production, it is generally not possible to localize EPR over a sufficiently long period of time, which significantly limits the applicability of the considered logistics scheme for this case.

If we draw an analogy with the movement of a “train,” then the DBR method can be considered as a kind of “semaphore” that periodically prohibits or allows movement in the direction of the ROP, depending on the current congestion of the path leading to it.

Work in progress (WIP) limit

A pull logistics system with a work in process (WIP) limit is similar to the DBR method. Its difference lies in the fact that temporary buffers are not created here, but a certain fixed limit of material reserves is set, which is distributed over all processes of the system, and does not end only at the ROP. The diagram is shown in Fig. 4.

This approach to building a “pull” management system is much simpler than the logistics schemes discussed above, is easier to implement and in some cases is more effective. As in the “pull” logistics systems discussed above, there is a single planning point - area 1 in Fig. 4.

A logistics system with a WIP limit has some advantages compared to the DBR method and the FIFO limited queue system:

• malfunctions, fluctuations in the rhythm of production and other problems of processes with a margin of productivity will not lead to a shutdown of production due to lack of work for the EPR and will not reduce the overall throughput of the system;
• only one process must obey scheduling rules;
• there is no need to fix (localize) the position of the ROP;
• It is easy to locate the current EPR site. In addition, such a system gives fewer false signals compared to limited FIFO queues.

An important feature of the “push” logistics systems discussed above is the ability to calculate the release time (processing cycle) of products using the well-known Little formula:

Release time = WIP/rhythm,

Where WIP- volume of work in progress, rhythm- the number of products produced per unit of time.

However, for small-scale and single-piece production, the concept of “production rhythm” becomes very vague, since this type of production cannot be called rhythmic. Moreover, statistics show that, on average, the entire machine system in such industries remains half underloaded, which occurs due to the constant overloading of one equipment and the simultaneous downtime of another in anticipation of work associated with products lying in line at previous stages of processing. Moreover, idle times and overloads of machines constantly migrate from site to site, which does not allow them to be localized and none of the above logistic pull schemes can be applied.

It was previously noted that these logistics systems work well for rhythmic industries with a stable product range, debugged and unchanging technological processes, which usually corresponds to mass, large-scale and mass production. But in the production of single and small-scale production, where new orders with the original technology of their manufacture are constantly launched into production, where the timing of product release is dictated by the consumer and can, generally speaking, change directly in the process of manufacturing products, the above-mentioned "pull" production logistics systems lose their effectiveness. .

Another feature of small-scale and single-piece production is the need to fulfill orders in the form of a whole set of parts and assembly units by a fixed date. This makes the task much more difficult production management, since the parts included in this set (order) can be technologically subjected to different processing processes, and each of the areas can represent an ROP for some orders without causing problems when processing other orders. Thus, in the industries under consideration, the effect of the so-called virtual bottleneck arises: the entire machine system on average remains underloaded, and its throughput low. For such cases, the most effective “pull” logistics system is the method of calculated priorities.

Calculated Priority Method

The calculated priority method is a kind of generalization of the two “push” logistics systems discussed above: the “supermarket” replenishment system and the FIFO system with limited queues. Its difference lies in the fact that in this system, not all empty cells in the “supermarket” are replenished without fail, and production tasks, once in a limited queue, are moved from site to site not according to FIFO rules (that is, mandatory discipline is not observed “ in the order received"), and according to other calculated priorities. The rules for calculating these priorities are assigned at a single point in production planning - in the example shown in Fig. 5, this is the second production site, next to the first “supermarket”. Each subsequent production site has its own executive production system (Manufacturing Execution System, MES), the task of which is to ensure timely processing of incoming tasks, taking into account their current priority, optimize internal material flow and timely show emerging problems associated with this process. A significant deviation in the processing of a particular job in one of the sites can affect the calculated value of its priority.

The “pull” procedure is carried out due to the fact that each subsequent section can begin to perform only those tasks that have the highest possible priority, which is expressed in the priority filling at the “supermarket” level not of all available cells, but only those that correspond to priority tasks. Subsequent section 2, although it is the only planning point that determines the work of all other production units, is itself forced to carry out only these highest priority tasks. Numerical values ​​of task priorities are obtained by calculating the values ​​of the criterion common to all in each section. The type of this criterion is set by the main planning link (section 2), and each production section independently calculates its values ​​for its tasks - either queued for processing, or located in the filled cells of the “supermarket” at the previous stage.

For the first time, this method of replenishing “supermarket” cells began to be used at Japanese enterprises of the Toyota company and was called the production equalization procedure, or “Heijunka”. Nowadays, the process of filling the Heijunka box is one of the key elements of the “pull” scheduling system used in the TPS (Toyota Production System), when the priorities of incoming tasks are assigned or calculated outside the production areas performing them against the backdrop of the operating “pull” replenishment system of the “supermarket” (“ kanban"). An example of assigning one of the directive priorities to an executing order (emergency, urgent, planned, moving, etc.) is shown in Fig. 6.

Naturally, in small-scale and especially single-piece production, the diagram of intra-shop material flows has a much more complex structure than its simplified image shown in Fig. 5. It is known that different parts included in the same order can be simultaneously processed in different production areas. However, considering the intra-shop route of only one part or assembly unit(DSU), this scheme can be considered fair: all DSU move from one section to another as they are processed in accordance with the technological process - Fig. 7. For example, for a specific part this may be a sequence of technological operations: milling -> boring -> grinding, etc.

The queue of production tasks transmitted from section 2 to section 3 (Fig. 7) is limited (limited), but, unlike the case shown in Fig. 8, tasks can change places in it, that is, change the sequence of their arrival depending on their current (calculated) priority. In fact, this means that the performer himself cannot choose which task to start working on, but if the priority of tasks changes, he may have to, having not completed the current task (turning it into the current WIP), switch to completing the highest priority one. Of course, in such a situation, with a significant number of tasks and a large number of machines on the production site, it is necessary to use MES, that is, carry out local optimization of material flows passing through the site (optimize the execution of tasks already in processing). As a result, for the equipment of each site that is not the only planning point, a local operational production schedule is drawn up, which is subject to correction every time the priority of the tasks being executed changes. To solve internal optimization problems, we use our own criteria, called equipment loading criteria. Jobs waiting to be processed between sites not connected by the “supermarket” are ordered according to the rules for choosing from the queue (see Fig. 8), which, in turn, can also change over time.

If the rules for calculating priorities for tasks are assigned externally in relation to each production site (process), then the criteria for loading the site’s equipment determine the nature of the internal material flows. These criteria are associated with the use of MES optimization procedures on site, intended exclusively for internal use. They are selected directly by the site manager in real time - see fig. 8.

In the method of calculated priorities, as a rule, MES systems are used, which operate with smaller assignment dimensions in relation to APS - up to 200 machines and 10 thousand operations over a planning horizon, which is usually no more than 10-15 work shifts. The reduction in dimensionality is due to the fact that MES takes into account many more technological constraints.

Systems of this type, when optimizing material flows within a production site, usually operate not with one or two scheduling criteria, but often with several dozen, which gives the site manager the opportunity to build a schedule taking into account various production situations. It is MES systems that operate with the so-called vector, integral criteria for constructing schedules, when several partial criteria are collected into one criterion, which makes it possible to calculate the priorities of the tasks being performed.

The efficiency of scheduling and recalculation is also the prerogative of MES, since recalculation can be carried out in one-minute increments. This does not mean, of course, that every minute the worker will be given new tasks, but indicates that all processes on the production site are controlled in real time, and this makes it possible to anticipate possible schedule violations in advance and take appropriate measures in a timely manner (Fig. 9 ).

In some cases, MES systems can create a schedule not only for machines, but also for Vehicle, teams of adjusters and other maintenance devices. No other system can handle such planning features as the formation of technological assemblies, planning the production of products with parallel planning for the production of the required set of equipment (devices, unique tools).

An important property of MES systems is the feasibility of the schedules compiled in them. If APS system schedules are more suitable for planning in large-scale production, where there are sharp deviations from production program, as a rule, does not happen (sustainable nature of production), then MES systems are indispensable in small-scale and custom production. It is noteworthy that parts awaiting the start of their processing on a specific machine can change their order, which is achieved in MES by adjusting the current schedule with changed priority values.

The method of calculated priorities assumes that some nimble “switchman” in the form of an MES system must run ahead of this logistics “locomotive”, switching the switches along the way in the optimal way. We will look at how this complex problem is solved in practice in the next article.

The synchronized production system is an advanced method of organizing production that allows your company to minimize losses, significantly increase profits and achieve outstanding results. The book describes in great detail all the stages of building synchronized production: from the introduction of visual management in the enterprise to the construction of a pull production system and continuous improvement of the entire production activities. The peculiarity of this publication is its exclusively practical orientation. Each stage of the synchronized production system is described in detail and supported by advice on its implementation, numerous illustrations and practical examples.

Hitoshi Takeda. Synchronized production. – M.: Institute of Complex Strategic Studies, 2008. – 288 p.

Download abstract ( summary) in the format or

Introduction. To achieve a state of synchronized production, as a rule, you need to rise to four levels of production culture (Fig. 1). The book proposes to break down the implementation of synchronized production into 13 stages, each of which is described in a separate chapter.

Rice. 1. Perfect production condition; To enlarge an image, right-click on it and select Open image in new tab

Stage 1. 6S Concept

Most of the changes needed to reform production can be carried out using the 6S concept. To put the 6S concept into practice, the entire staff must be involved: everyone must be interested in the changes, otherwise there will be no benefit from 6S.

WHAT IS 6S?

• SEIRI – sorting; freeing workers from unnecessary items and organizing a storage system.
• SEITON - rational arrangement; arrangement of the necessary items in an order that makes them easier to find and use (Fig. 2).
• SEISO - cleaning; maintaining cleanliness in the workplace.
• SEIKETSU – standardization.
• SHITSUKE - improvement.
• SHUKAN is a habit.

It is necessary to radically change the existing ideas about both the workspace and the principles of production organization. Many behavior patterns are so deeply ingrained that people are simply unaware of them. The goal of implementing 6S is to recognize these habits and radically change them so that there is no return to previous ways of working. Reforming production is impossible as long as the staff behaves as before.

Stage 2. Leveling and smoothing production

The period during which a product is produced is called takt time. A method that allows products to be produced in accordance with takt time is called smoothed production. Each machine must process products in accordance with the takt time, otherwise the machines will be idle every now and then or work under overload. Resolutely eliminate all stocks: they cause only harm. When inventory levels drop, different types of problems come to the surface. It can be formulated in another way: without eliminating losses, you cannot get rid of stocks.

Smooth production allows you to reduce inventories at all stages of production. Synchronized production should be built in the direction opposite to the movement of products, that is, first introduce it at the last production stage, and then move to the first stage. It should be remembered that the pursued goal is to achieve the efficiency of the axes of the production system, and not its individual elements (for more information about the dangers of local optimization, see, for example,).

Production leveling is the distribution of production volumes, allowing each shift to produce the same number of products. Production smoothing is the equalization of the volumes and types of products produced daily. The ultimate goal of smoothing production is to produce products that meet consumer requirements with a minimum of production costs.

Leveling => Smoothing => Increasing the number of cycles (Fig. 3).

Rice. 3. Leveling, smoothing, increasing the number of cycles; * – there may be a typo in the picture, you should read 20

Stage 3. Unit flow

One-piece flow allows you to coordinate activities at different stages of production. However, many enterprises still produce products in large quantities, which leads to a pile of inventory that accumulates at each work station. When there are many operators on the line, the ability to work as a team becomes especially valuable. One-piece flow helps optimize team operations.

For the efficient functioning of the flow of single products, it is necessary to establish a standard buffer stock - a minimum stock of parts and products on the line, ensuring continuity of the flow. Buffer stock is stored near workstations. When forming effective flow single products, you need to pay attention to three main points: equipment, personnel and production (Fig. 4).

Stage 4. Flow production

In a manufacturing context, "flow" refers to the continuous movement of products through all stages - from the supply of material to the finished product. Raw materials, standards for performing operations, kaizen events, and exchange of information between processes are the elements from which the formation of an effectively functioning flow begins. The end result that this method of production leads to is the production of only necessary products and the standardization of all operations and processes in the enterprise.

The first step is to create a backlog of parts at the end of each production line. Workers must perform operations in a strict sequence, then the flow will be smooth. To do this, it is necessary to train operators to operate several machines, that is, to expand their qualifications. Then, using kaizen methods, you should reduce the inventory level of the necessary parts (this should be done gradually, step by step). In particular, the U-shaped arrangement of the equipment will allow maintaining the continuity of the flow. Machines should be positioned as far as possible closer friend to a friend in the same sequence in which the operations are performed.

It is advisable to place equipment in workshops counterclockwise. Why is this so? The product flow moves from right to left, and right-handed workers pick up workpieces with their right hand and change the position of switches with their left hand.

For efficient functioning continuous production workers must have several skills. This will allow you to vary their loading. Depending on their skill level, workers are divided into three groups: groups A, B and C (Fig. 5).

Visual and audible signals are visual controls. They are used to alert about deviations from the normal course of work and interruptions in flow continuity. If problems arise with quality, mechanical defects or malfunctions, the worker must press the button and call the foreman or a member of the repair department. If a problem arises, do not rush to stop the line, but call the foreman or foreman. He will stop at the right moment (when other workers have completed the cycle). In those cases: when the lines are equipped with a stroke limiter, if a malfunction occurs, the stop will occur automatically (Fig. 6).

Step 5: Reduce Batch Sizes

Reducing batch sizes, which is inextricably linked to reducing changeover times, is carried out in order to produce only the necessary products in the required quantities and in the required quantity. right time and better respond to fluctuations in consumer demand and changing market conditions. Stocks should be kept to a minimum production costs- decrease. Mastering quick changeover operations is an important prerequisite for creating a continuous flow of one-off products and increasing profits.

Among various types The most dangerous loss is overproduction. Overproduction leads to excessive loading of workers on processes, hides problems, increases the buffer stock, which, in turn, generates new losses. To achieve efficient work production system, you need to figure out how to reduce the buffer stock and organize a continuous flow of single items. Releasing products in large quantities is a direct path to overproduction. In order to optimize changeover operations, it is necessary to abandon existing stereotypes and form new order performing operations (Fig. 7).

Signal kanban is used on lines where products are produced in batches. Triangular kanbans signal the start of production, while other types of kanban signal the removal of materials. Kanbans are a means of coordination and information transfer, with their help the volume of products is regulated and batch sizes are reduced. Proper use of kanbans and containers increases production efficiency.

Stage 6. Storage areas for parts and products

Although this chapter focuses on the production line, the principles that optimize the flow of information can be successfully applied in offices, service organizations, and other sectors of the economy. Visual management tools allow any worker to assess the production situation without searching for any additional information. It is especially important for managers to be able to monitor the pace of production directly on the shop floor, since in this case they can instantly respond to any deviations that arise.

The basic principle that should be followed when developing designations for the location of objects is that every detail should have its own place. For example, a part is identified by a number, a location by a letter designation.

After assembly, finished products are immediately moved to a designated storage location, so finished product storage should also be considered as part of production process and accordingly they must be subject to all rules regarding the organization of storage and movement. The same applies to the principle of “first in, first out”: this principle should become universal.

Containers should be used to store and move products in the enterprise. It usually doesn't occur to us to consider empty containers as indicators. When production rules have been developed for using containers as indicators of material levels, identifying material shortages by counting empty containers is not difficult.

As part of the synchronized production system, all storage facilities are self-regulating. If the operation of the storage facilities is not automatically adjusted according to the needs of the downstream process, this means that the storage facilities are not fulfilling their role, but are simply a place in which excess production accumulates.

Step 7: Production according to takt time

Takt time is the time interval for product release, set by the subsequent process (consumer). Work in progress should be kept to a minimum, but care must be taken to ensure that downstream processes receive the required parts in the required quantity at the right time. Takt time is calculated by dividing the available working time by the number of products that need to be produced per shift.

When releasing products, slowing down or speeding up the pace should be avoided. There is nothing worse than releasing products ahead of schedule (Figure 8).

Do you think that the condition of your working line is worse than ever? Eliminating waste begins with the awareness of shortcomings. In an effort to identify losses, do not immediately try to figure out how to eliminate them; you'll do that later. First, it is very important to identify losses, down to the smallest. After this, you can move on to sequentially, step by step, eliminating them. Thus, the ability to see losses (muda) around is developed (Fig. 9). When reducing the number of workers on a line, the most skilled workers should be removed first. Before being transferred to other areas, these workers must be assigned to carry out kaizen activities on the line for a month. The true measure of productivity is easy to track when production volumes are reduced. When production volumes increase, in no case should the number of workers employed on the lines be increased.

Stage 8. Control of production volumes

Improvements should help reduce costs. In order to visually present the results of these actions, one of the visual management tools is used - a schedule for recording and distributing production volumes. Its main purpose is to help create a flexible, continuous flow that functions without disruption.

Controlling production volumes helps to accomplish three important tasks:

• foremen, workers and senior managers receive specific numbers and their visual display, which allows them to substantively discuss the situation and ways to improve it;
• control of production volumes helps to maintain delivery deadlines;
• production volume control allows you to track production costs.

Production status monitoring, carried out every hour, allows you to quickly respond to deviations. It also helps to develop a conscientious attitude among workers to carry out production tasks, because, having information about the current situation, they can regulate the pace of work themselves, if necessary. In this way, it can be ensured that by the end of the shift, the needs of the downstream process will be fully satisfied. This method also allows you to track production time for each product and monitor how much production costs have been reduced during the shift.

Two types of schedules are used as tools to take into account and control production volumes and production times of individual products:

• Production volume control schedule. Every hour throughout the week, data on current production volumes and product manufacturing times are entered into the schedule. the data is then compared with planned indicators and analyzed. Regular use of this chart allows you to identify bottlenecks in production.
• Graphical display of fluctuations in production volumes and production times. Based on the data from the previous graph, a diagram is drawn that compares actual and planned data on the time and volume of production during the month. This allows you to see the dynamics and understand how to proceed.

If nothing changes, production costs will certainly increase. The most significant losses are caused by the following factors:

• downtime on the line (costs of paying idle workers, costs of storing work in progress, other costs);
• personnel errors (repeated processing, loss of consumer confidence);
• mechanical defects (fall in output, losses due to quality defects, repair costs);
• errors in planning (additional shifts, overtime pay);
• incompleteness of kaizen actions (losses due to unused potential, low productivity).

To develop leadership qualities, you must adhere to strict self-discipline and be prepared to self-learn. The responsible foreman ensures that workers complete assigned tasks. Labor safety on the site, the quality of products, quantity of products, production time of products and the level of production costs largely depend on the behavior and views of the leader.

The responsible foreman is one of the most important links in the chain of formation of a synchronized production system. He must convince workers that improvement is impossible without effort. The workers are not used to standing idle. If you don't look after them, they will start doing work that should not be done under any circumstances. The foreman must convince workers to refrain from working during the waiting period.

Three tasks that the foreman must ensure: ensure high quality products, meet delivery deadlines, and reduce production costs.

Stage 9. Standardized work

Standardized work is the central element of a production system. Moreover, it would not be an exaggeration to say that without the use of standardized work, synchronized production does not exist. The most important aspect of standardization is to create a system that will support ongoing compliance with standards. Standards should be strictly followed, even if they are far from perfect, since kaizen in an enterprise is only possible if there are standards. To ensure that workers do not neglect standards, it is necessary to involve them in the process of creating standards.

Five tasks of standardized work (regulation of manual labor):

• The basis of all operations on the gemba.
• Identifying areas of kaizen actions and consolidating improvements in new standards.
• Providing new workers with accurate and complete instructions.
• Prevention of unnecessary operations.
• Guaranteeing quality and labor safety, ensuring the required production volumes and an acceptable level of costs.

Three elements of standardized work

1. Cycle time (time to produce one product or part)
2. Sequence of operations (assembly or manufacturing of products carried out in a certain time sequence)
3. Availability of standard buffer stocks (an absolute minimum of stocks that ensures the continuity of rhythmic and cyclical work).

Advice. If markings are made on the floor of the workshop that correspond to the sequence of procedures (for example, using arrows and numbered lines), then operators will complete the work faster and with better quality.

The introduction of standardized work makes it possible to identify and eliminate losses and improve production processes (Fig. 12).

Step 10: Quality Assurance

Quality comes from work. Control procedures do not create quality as such. Collective quality control is ineffective: "I process products - you check the quality." The self-control procedure allows workers to verify how accurately the production standards are observed in the production of products. The worker checks the quality of manufactured products at specified intervals (every hour) and enters the data into the self-control sheet. Checking the results of his work, he monitors the quality of the finished product and ensures that low-quality products do not enter the subsequent process (for more details, see and). Poka-yoke are devices built into machines and mechanisms that provide automatic error protection.

Stage 11. Equipment

The value of machines and mechanisms is determined not by the degree of wear or service life, but by the ability to make a profit. Enterprises must take care to extend the life of the equipment. Machine tools must be regularly cleaned, checked and lubricated to ensure continued performance. The cause of defects should be sought based on the principle of CG: gemba - a specific place, gembutsu - a specific defective object, genjitsu - specific conditions. Equipment availability is the proportion of time during which a line or machine is in working condition.

Stage 12. Kanban system

A kanban is a card that specifies which items should be removed, how many, and how those items should be produced. The subsequent process removes strictly necessary products in the required quantity and at the required time, the previous process produces only what was ordered from the subsequent process. Cards containing information about the withdrawal and transportation of materials and products are called withdrawal kanbans. Cards containing production instructions are called production kanbans. These two types of cards circulate between processes, ensuring their regulation. Kanbans are carriers of information as well as downstream process requirements.

In traditional manufacturing systems, products are “pushed” by a previous process into a subsequent production stage. Products are released according to a schedule based on forecast demand. This means that the previous production stage produces and moves items that were not ordered. With this approach, excess production is inevitable. The only way to eliminate losses caused by overproduction is to change the production system itself, i.e. move to producing only the necessary products in the required quantity and within the required time frame. Such a system can be compared to a supermarket, in which goods are put on the shelves only to replenish goods that have already been sold, in other words, after the subsequent process (the consumer) has withdrawn what is needed. The most important principle of such a system is the availability of products for which there is demand in the required quantity and at the required time.

Three functions of kanbans: automatic transmission of information - production instructions, integration of material and information flows, effective tool kaizen.

Conditions prior to the introduction of kanban into practice:

• creation of continuous production
• batch size reduction
• smoothed production
• reduction of transport cycles and unification of routes
• continuous production
• addresses and storage locations
• type of packaging and types of containers

Rules for using kanbans:

• Every container should have a kanban on it.
• After the first item is removed from the container, the kanban is removed and placed in the kanban box/rack
• the subsequent process removes products from the previous process
• product release is carried out in the same sequence in which products are withdrawn by the subsequent process
• it is necessary to produce as many products as were removed by the subsequent process
• if there is a shortage of parts at a subsequent stage, you must immediately report this to the previous stage
• Kanbans should be put into circulation and their circulation monitored at the same production site where they are used
• Kanbans should be handled as wisely and carefully as money
• never pass on defective products to the next production stage

The introduction of kanbans should begin with the last production stage. Kanbans used at the final stage of production are called supply kanbans. In this case, kanban cards are also delivery orders. If the enterprise does not use delivery kanbans, then their function is performed by kanbans for the withdrawal of finished products. The role of the customer in this case is performed by the production planning department.

Once the finished product removal kanbans are attached to the parts containers, the assembly kanban becomes a production order to make new parts. Assembly kanbans in the order they are received (i.e., in the order parts are removed) are placed on a production order tracking board located at the beginning of the assembly line. This board is a visual management tool. The withdrawal kanban acts as an order for the movement of products and parts. Products that are withdrawn for production needs must be immediately replenished with the same ones (Fig. 13).

A production kanban is an order for the production of a specific product. Production kanbans are removed from containers immediately after parts are removed and moved to finished goods storage. The production kanbans are then placed in the order they are received on the production order tracking board. You can reduce the number of kanbans in circulation using kaizen actions.

It is very important to use a special red box as a visual management tool to synchronize production processes. The main task control on the gem is the resolution of emergency and problem situations. Using red boxes helps identify bottlenecks in your kanban system and allows you to take immediate corrective action.

All production orders must arrive at the gemba in the form of kanbans. Not on the gem production plan in the traditional interpretation of this concept: the basis for production is demand at the next stage. The kanban must include the product name and number, part names and numbers, location, container type, number of items in the container, and registration numbers.

At the beginning of the implementation of kanbans, workers often do not understand the feasibility of their use; kanbans seem to them to be an additional burden. That's why it's important to initially explain the purpose of using kanbans, provide workers with clear instructions, and discuss the benefits of this tool for improving production. Kanbans are also a critical tool for implementing and maintaining just-in-time.

Stage 13. Interrelation and systematization of the stages of synchronized production

When implementing a synchronized production system, it is necessary to remember the interrelationship of the stages. An attempt to implement one separate stage without taking into account the relationships within the entire system will certainly end in failure (Fig. 15).

The second group of principles includes most of the TPS tools used to improve production processes, development methods new products and provision of services. They are often called the “lean manufacturing philosophy.” However, as important and effective as these tools and processes are, they are only a tactical aspect of the Toyota approach and can only achieve long-term results when combined with an appropriate company-wide management philosophy.

Principle 2. Organize the production process as a continuous flow, which helps identify problems.

This principle involves restructuring technological process in a way that creates a continuous flow that effectively adds value. At the same time, the time that unfinished work remains idle must be reduced to a minimum.

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

Unlike mass production, organized according to the principle of specialization (grouping of similar work) and producing goods in batches, one of the main elements of TPS are the so-called “cells” that create flow of single products.

A cell is a collection of people, machines or workplaces organized and operating in accordance with a sequence of technological operations. They are created to ensure the flow of single products (services) that one after another 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 to organize the flow of one-piece products across all types of work, be it design, order taking, or production itself.

The formation of cells involves the so-called multiprocess labor organization system, that is, the maintenance by each employee of several machines for various functional purposes (in contrast to a multi-machine system, in which one operator services identical 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 depicted in Fig. 22 and 23 using the example of the process of creating computers.

Rice. 22.

Rice. 23.

As you can see, creating a flow of single items involves an almost complete elimination of inventories. According to lean manufacturing philosophy, inventory prevents problems from being identified. Indeed, with the traditional approach, if a failure occurs at one stage of the process, the other stages will proceed as before, since there is enough inventory. When organizing the flow of single products, in the event of an error in any section, the entire cell stops, and this creates the need immediately eliminate the cause of the failure. Thus. flow is the key to continuous improvement (“kaizen”) and people development.

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

So, if the working day is 8 hours (480 minutes), 20 days per month, and the consumer purchases 19,200 units of products per month, then 960 units need to be produced per day, that is, one product per 30 seconds. With a properly organized flow of single products, 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 to mass production of goods or services. However, in principle, these concepts are applicable to any repeating process, as long as you list its steps and identify and eliminate waste.

The advantages of such an organization of production include:

• 1) embedding quality- each operator is at the same time a controller and tries to solve the problem on the spot, without transferring it to the next stage; if he missed defects, they will be detected very quickly and the problem will be corrected immediately;
• 2) true flexibility- reducing the order fulfillment time allows us to produce what the consumer really needs at this particular point in time;
• 3) productivity increase- the organization of cells allows you to immediately see who is overloaded and who remains idle. In this way, value-adding work can be easily costed and how many people are required to achieve a given output;
• 4) freeing up space- in the cells, all blocks are fitted to each other, and stocks take up almost no space;
• 5) increased safety- reducing the number of material movements automatically reduces the number of industrial accidents;
• 6) boost morale- employees can quickly see the fruits of their labor, which increases job satisfaction;
• 7) inventory reduction, which leads to a reduction in storage costs, physical and moral aging of materials, reduces the number of defects from unnecessary loading and transportation operations, and also frees up working capital.

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

• 1) Creating a Pseudo Stream consisting in a simple rearrangement of equipment. By moving pieces of equipment together, companies create the appearance of a cell, but at each stage they continue to deal serial production, 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 creating a flow may lead to certain costs, the company refuses decision taken. This can happen in any of the following situations:
  • - stopping one of the equipment units leads to the cessation of cell operation;
  • - readjustment of one of the equipment units takes longer than expected and slows down the operation of the cell as a whole;
  • - you have to invest money in a technological operation that was previously carried out at another enterprise in order to produce it locally.

Maintaining a cell requires discipline, which is very difficult for many businesses to maintain. However, in the long term, all the troubles and costs are paid off by achieving good results.

Principle 3: Using a “pull” system to avoid overproduction.

One of the fundamental principles of TPS is "pulling"

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

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

The present one-piece flow represents zero inventory system, which produces goods only when the consumer needs them. But since such a flow is practically 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 reserves are created between the stages of the process, the volume of which is strictly controlled.

The pull concept is based on how American supermarkets operate. In any supermarket, the stocks of goods on the shelves are replenished as customers sort them out, that is, as they are consumed. In the context of a shop floor, this means that the production or replenishment of parts in Stage 1 must occur as the next Stage 2 has used up almost all of the parts produced in Stage 1 (i.e., only a small number of spare parts remain). 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 specified minimum. Thus, until the consumer has used a certain product (did not “pull it off the shelf”), it remains in stock and no replenishment occurs. Overproduction does not go beyond a limited number of products, and a close connection is established between consumer demands and production volume.

A special alarm system lets you know that the stock needs replenishment. IN lean manufacturing it looks extremely simple: empty containers and special cards are used as warning devices. If an empty container is returned to you, this is a signal that it needs to be refilled. a certain amount details or send the 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 uninterrupted functioning of the “just in time” system. The functions and rules for using this system are given 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. In this case, the stock of products is replenished only as they are consumed;

• - work in progress and inventory storage 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. Uniform 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) Mu da - actions that do not add value. These include the eight types of losses mentioned above.
• 2) M$ri - overload of people or equipment. Muri forces a machine or a person to perform at its limit. Overloading people threatens their safety and causes quality problems. Overloading equipment leads to accidents and defects.
• 3) M$ra - unevenness production schedule, in some way is the result of the first two causes. The reasons for unevenness are an incorrectly drawn up schedule or fluctuations in production volumes caused by internal problems (downtime, lack of parts, etc.) Unevenness in the level of production makes it necessary to match the available resources (equipment, materials, people) to 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 leveling 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 production will be disorderly. Therefore, if twice as many orders are received on Monday as on Tuesday, the staff will have to work overtime on the first day, and on the second they will have to go home before the end of the working day. To align the schedule, it is necessary to find out the consumer’s needs (for example, for a week), decide on the product range and volume, and draw up a balanced schedule for each day. Let's say we know that for every five A, five B are made. Then we can level 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 usage labor resources and equipment;
• - balance orders issued to previous processes and suppliers (at the previous stage, a stable set of orders is received, which allows reducing the amount of inventory, and therefore costs).

Thus, the use of heijunka eliminates muri and mura and standardizes the work, making it much easier to identify losses of other types.

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

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

Lean manufacturing suggests that quality should be built into the production 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 "poka-yoke"- “error protection”. The following examples of its action can be given:

if there is an error in the workflow, the part will not fit the tool;

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

• - if there is 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 you skip one operation, the next stage will not begin.

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 called autonomy - endowing 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, autonomy changes the essence of equipment operation. If the working process proceeds normally, the machine does not need an operator. Human intervention is only required in the event of failures in the production process. Therefore, one operator can serve several machines. Thus, thanks to autonomy, the number of workers involved is reduced and overall production efficiency is increased. Note that the creator of TPS Taiichi Ohno considers this system one of two basic principles lean manufacturing (another is just-in-time methodology).

It should be noted that the integration of quality first of all depends on the personnel, and then on the technologies used. Company employees must take responsibility for quality assurance; this must be a defining part of their value system. Technologies are only tools that help implement the philosophy of quality in practical activities.

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

• - quality determines the real value of manufactured products;
• - It is necessary to use equipment that can independently recognize problems and stop when they are identified, as well as a visual system to notify the team leader and team members that a machine or process requires their attention. Jidoka (machines with elements of human intelligence) is 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 “the first time” and become an integral part of the company’s production culture.

principle b. Standardization of tasks for continuous improvement.

The basis of flow and pull in TPS is standardization, i.e. using stable, repeatable work methods, which makes the result more predictable, increases the coherence of work and the uniformity of product output, and facilitates the process of integrating quality.

The basis of the standard of work in lean manufacturing consists of three elements:

• - 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 standard operations sheets, which hang above each workplace and are an important means of visual management of the production process.

Toyota's approach involves not only the unification of tasks performed by shop floor workers, but also the standardization of work processes performed by office workers and engineering workers. In addition, Toyota applies standards to product development and industrial equipment.

Contrary to the widespread belief that standardization makes work mechanical, in lean manufacturing, on the contrary, it empowers workers and is foundation 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 can you think about improving it. In other words, It is impossible to make improvements to work that you do in a new way every time.

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

• 1) providing workers with a strict procedure that they must adhere to;
• 2) providing them with the freedom to introduce innovations, allowing them to creatively approach solving complex problems in relation to costs, quality, delivery discipline, etc.

The key to achieving this balance lies in a specific approach to creating standards.

Firstly, standards must be sufficiently specific,

to serve as guidelines for practical activities, but at the same time quite wide to allow some flexibility. Implementation standards self made repetitive nature, have a high level of specification. When designing, where fixed quantitative indicators missing, the standard should be more flexible.

Secondly, Improving standards should be done by people who do the work themselves. No one likes to be forced to follow rules and procedures made by others. Imposed rules that are strictly enforced 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 set out in the standard without dissatisfaction. At the same time, Toyota's approach involves capturing accumulated knowledge and best practices in new standards. Thus, the experience accumulated by one employee is transferred to the one who replaces him. And that is why standardization in lean manufacturing is the basis for continuous improvement, innovation and personnel development.

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

To ensure that employees can 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 one to understand at a glance how work should be performed and whether there are deviations from the standard. It may provide for the designation of a place allocated for any objects; an indication of the number of objects that should be installed in this place; a visual description of standard procedures for performing any work and other types of information important for organizing the flow. In the broadest sense visual control is a complex of information of all types provided in a “just in time” system for the purpose of fast and proper implementation of operations and processes. The visual control system ensures 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 the smooth flow of one-piece items. Examples of such tools are kanban, andon, and standard operations systems. If the container doesn't have a Kanban card on it that tells you to fill it, then the container is out of place. A filled container without a kanban card is a sign of overproduction. Andon signals a deviation from standard operating conditions. Scheme standard procedure task execution is posted so that the best known method for ensuring flow in each work area can be seen at a glance. Noticed deviations from standard procedure indicate 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 (in Japanese they are called seiri, seiton, seiso, seiketsu and shitsuke, in English - Sort, Stabilize, Shine, Standardize, Sustain) are given below.

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

Rice. 24.

You need to start by sorting what is in the office or workshop. During the sorting process, what is needed for daily work to create added value, is separated from what is used rarely 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 point is maintaining cleanliness, which must be maintained constantly. The pillar of the first three S's is standardization. Improvement is a team-oriented methodology for teaching and continually supporting the first four S's. Managers play a decisive role in its implementation and must conduct regular reviews of its implementation.

One example of visualization within the 5S program is tool stands. In the space reserved for the tool on the stand, its outline is depicted. The outline of the hammer shows where the hammer should be, and if it is not there, it is immediately obvious. Thus, these stands help to visualize the standard that defines the arrangement of tools, and one glance at them is enough to see deviations from this standard.

The control means used in TPS (tags, stands, sound signals, 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 carried out alone, the employee loses contact with the team and, more importantly, usually (if his direct duties do not require the use of a computer) leaves the area of ​​his practical activity. The problem can only be assessed adequately seeing everything with my own eyes. That is why lean manufacturing uses controls that do not replace, but complement a person with senses. And the most powerful visual tools are right there in the workplace, where they can't be overlooked and where hearing, sight, or touch tell an employee whether he or she is meeting or deviating from a standard.

The need for visualization determines a number of standards for the preparation 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 AZ 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, determination of the root cause of the problem, proposal of alternative solutions, argumentation for choosing one of them, cost-benefit analysis. All this needs to be fit on one sheet of paper, using as many numbers and graphs as possible. Over the past few years, Toyota has seen a movement towards moving to A4-sized reports - the company is convinced that more can be expressed in less, i.e. the very essence 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 where deviations from the standard occur;
• - refusal to use computers, monitors, etc., if they

distract the worker from the area of ​​his practical activity;

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

The results of using a well-thought-out visual control system are increased productivity, quality and safety, facilitated intra-organizational communication, reduced costs and an overall increase in the transparency of the work 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 equipment, the process must often be completed manually first;

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

• - before introducing new technology and equipment, tests should be carried out under real operating conditions;
• - it is necessary to reject or change technologies that run counter to corporate culture, as well as those that violate the stability, reliability or predictability of processes;
• - with all this, it is necessary to quickly implement 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), already described by us in this manual, namely: technology is implemented only if it corresponds to the “hedgehog concept” of a lean enterprise (improving the organization of the flow of single products) and its corporate culture.

In the process of acquiring new technology, Toyota prefers to move slowly, often concluding that a given new technology does not meet the stringent requirements of supporting people, process, and values, and discarding it in favor of simpler manual methods. However, the company can serve as a global benchmark for the use of modern methods in order to optimize the value adding process.

New technologies at Toyota are introduced only after experimental testing with the participation of a wide range of specialists representing different functional departments. Thus, each technology is thoroughly assessed and tested to ensure its suitability for adding value. The company carefully analyzes the impact that this innovation can have on existing processes. It is in them that the nature of the work to create added value is first explored, additional features eliminating losses and smoothing flow. Toyota then uses the pilot site to refine the process with existing equipment, technology and people. Once the process has been improved as much as possible, the company again asks whether the introduction of new technology will lead to additional process improvements. If the answer is yes, the new tool is carefully analyzed to determine whether it is consistent with Toyota's philosophy and principles, which suggest that: the value of people is greater than the value of technology;

• - decisions must be made based on consensus;
• - the main attention in the work process should be paid to eliminating losses.

If a technology does not meet these principles, or there is even a remote possibility that it will adversely affect stability, reliability or flexibility, Toyota will reject it or delay its application until such issues have been resolved.

If the new technology is found to be acceptable, it is then implemented in a manner that ensures continuous flow throughout the production process and helps workers perform tasks more efficiently within Toyota's standards. It means that innovation should not distract people from creating value(i.e. be suitable for use directly in the workplace), and both- It is important to ensure visibility of the process.

The described approach applies to all types of technologies, including information technologies. The company sees them only as a tool that exists to support people and processes. To improve the productivity of any activity, you must first change the way it is performed. Information Technology most often they only reflect existing processes in the company, and therefore are not able to eliminate losses on their own.

• This technology is also often called a Just In Time (JIT) system.
• The author of the “fast 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 industrial Toyota systems. The principles of Shingo, first tested in Japanese enterprises, are now actively used in many European and American corporations. For more information on this, see: Shingo Shigeo. Fast changeover: Revolutionary technology for production optimization - M: Alpina Business Books, 2006. - 344 p.
• 2 Initially, the devices were called “baka-yoke” (“foolproof”), but one of their creators, Shi-geo Shinyu, noticed that the workers were unhappy with this name. Therefore, the term was subsequently replaced by “poka-yoke (“error protection”), which reflects the logic of the production process, since defects can be caused not only by “fools” people.
• The word "andon" means "light signal calling for help."
• Taiichi Ono. production system Toyotas. Moving away from mass production. - M.: Institute of Comprehensive Strategic Studies. - 2006. - P. 34.