Lean, basic concepts
Lean(LeanProduction) - a system for organizing and managing product development, operations, relationships with suppliers and customers, in which products are manufactured in strict accordance with the needs of consumers and with fewer defects compared to products made using mass production technology. This reduces the cost of labor, space, capital and time.
lean-enterprise(Lean Enterprise) is a business system for organizing and managing product development, operations, relationships with suppliers and customers, using the principles, practices and tools of lean manufacturing to create well-defined customer value (goods and services with higher quality and fewer defects , with less labor, in a smaller production area, with less capital and in less time compared to the traditional mass production system).
Lean businesses involved in the production of a particular family of products operate on the basis of an agreement according to which they determine the value of products from the perspective of the end consumer, eliminate non-productive activities from the value stream, and perform activities that create value in the form of a continuous flow as they "pull" products by the client. The cooperating enterprises carry out the listed procedures continuously throughout the entire life cycle of this product family.
The presented definition of the system of lean manufacturing very concisely expresses the essence of this concept. Let's try to uncover some provisions of this definition.
An important principle of the concept of lean manufacturing is continuous improvement and participation in this process of the entire team.
"Creating well-defined customer value" involves understanding what is value for the consumer. And here you can not rely on only your own knowledge. Work should be carried out to identify all components of customer value, sometimes directly with the end consumer of the product / service. This is a guarantee that the requirements of the consumer will be satisfied most fully and at the lowest cost (excessive work is excluded).
If a company is engaged in lean manufacturing, it means that it puts the interests of the customer, buyer, client, partner and its own employees at the forefront, and everyone benefits from this. Therefore, the introduction of lean manufacturing is the best business card for presenting the company to partners and customers.
“With less labor, in less space, with less capital and in less time”- in the concept of lean manufacturing, this means an exception all kinds of losses(overproduction, over-processing, waiting losses, transportation losses, personnel movements, losses due to defects/rework, etc.).
2. The concept of lean manufacturing is based on five principles that guide managers in the transition to lean manufacturing:
Definition of value each product family from the customer's point of view.
Definition of all stages of the value stream for each product family and eliminating, to the extent possible, non-value-adding activities.
Aligning operations that create value in a strict sequence that ensures the smooth movement of the product in the stream, directed to the client.
At the end of the flow formation - creating the possibility of "pulling" value customers from the previous stage.
Once value has been determined, identifying value streams, eliminating stages that cause waste, and drawing system formation- repeating the whole process anew as many times as necessary to achieve a state of perfection in which absolute value is created and there is no waste.
It is necessary to explain what is push production and pull production.
Push production - processing products in large batches at maximum speed based on forecasted demand, followed by the movement of products to the next production stage or warehouse, regardless of the actual pace of the next process or the needs of the customer (consumer). Within such a system, it is almost impossible to implement lean manufacturing tools.
Pull production- a method of production management in which subsequent operations signal their needs to previous operations.
There are three types of pull production:
Supermarket pull system (reimbursement/replenishment system) is type a pull system.
Sequential pull system - type c pull system.
Mixed pull system – type c pull system.
Supermarket pull system- the most popular. With it, at each production stage there is a warehouse - a supermarket, in which a certain volume of products manufactured at this stage is stored. At each stage, as many products are produced as were withdrawn from the supermarket. As a rule, when a product is withdrawn from a supermarket by a subsequent process - a consumer, the latter sends up to the previous process information about the withdrawal using a special card (kanban) or otherwise.
Each process is responsible for restocking its supermarket, so the operational management and search for objects of continuous improvement (kaizen) is not a big deal. However, its application is complicated in the presence of a large number of types of products.
Sequential pull system it is advisable to use with a large range of products produced by one process, i.e. when it is difficult or almost impossible to maintain a stock of each type of product in the supermarket. Products are essentially made-to-order, with total stock in the system kept to a minimum. A consistent system requires short and predictable lead times, and a good understanding of the order flow from the customer. The operation of such a system requires very strong leadership.
Mixed Pull System- involves a combination of the two listed systems. It is advisable to apply it when the 80/20 rule is in effect, i.e. when a small proportion of product types (about 20%) is most of daily production volume (approximately 80%).
All kinds of products are divided into groups according to output volume: high volume, medium volume, low volume and rare orders. For the "rare orders" group, it is advisable to use a sequential pull system. For other groups - the pull system of the supermarket. With a mixed pull system, it may be more difficult to manage improvement and detect deviations.
3. Lean manufacturing tools.
Lean manufacturing concept is aimed at maximizing resource savings in the production process, primarily temporary. The basic principle of this concept is to identify and eliminate processes that do not bring added value or reduce it (for example, processes leading to excess inventory, waiting processes, processes of excess transportation, processes of excessive processing, processes that create defects, etc.).
It is advisable to use the tools of the concept of lean production to determine and eliminate unproductive expenditure of resources when optimizing the internal processes of Russian Railways.
Under the value stream understand all the activities - both value-creating and non-value-creating - that allow a product to go through all stages of the process:
1) from concept development to the release of the first product,
2) from order acceptance to delivery. These activities include the processing of information received from the client, as well as operations to transform the product as it moves to the client.
When lean manufacturing was widely introduced into management practice, it turned out that it was in dire need of business process description.
Business can be characterized as a set of interrelated and interacting processes. Then, if we carefully describe each process and study the interconnections of processes, then we will understand how any business works and we can use this description for a variety of purposes.
For the practical application of the lean manufacturing system, it is necessary to be able to systematically describe business processes, that is, the most important business processes that bring us money in payment for our products or services.
How to learn to see processes? At the enterprise, first of all, we see machines, apparatus, transport systems, people engaged in their work.
Process it is a sequence of actions aimed at obtaining some product and / or service. Moreover, these actions are distributed in time and space. It is rare to see these actions all at once from one point. "So what?" - you say. The processes are running, everything is working. Why document them, describe them, is it not enough to keep everything in your head, as it is now?
First of all, the description of the process speeds up the exchange of information and reduces the risks of making untimely and erroneous decisions and actions.
Processes can be described in words, but words are understood differently. In this regard, the most obvious and accessible is the visualization of business processes using a visual picture of the process.
First of all, we need a description of the process as it currently exists in order to get a starting point for further improvement. Having a current description of the process, we can build an "ideal" process and outline a transition plan to it. And only after that begins the continuous improvement of the process according to the concept of lean manufacturing.
Lean manufacturing tools are:
Elimination of hidden losses.
Quick changeover (SMED).
Just-In-Time (JIT) system.
Tag (kanban).
Error prevention.
Mapping the value stream.
And others.
Elimination of hidden losses
In any system, in any process - from manufacturing and assembly to hospitality, healthcare, transportation and social services - there are hidden losses. Identifying and eliminating these losses saves millions of dollars annually in organizations that regularly evaluate their performance against lean manufacturing standards. In Lean, waste refers to any activity that consumes resources but does not create value for the customer. There are two types of losses.
Losses of the first kind do not create value, but they cannot be abandoned with existing technologies and fixed assets.
Losses of the second type do not create value, but they can be quickly eliminated.
The hidden waste that can be found in mass production falls into seven categories:
Overproduction
Expectation
Movement
Transportation
Overprocessing
Fixes
These losses increase production costs, without adding consumer value that the customer really needs. They also increase the payback period of investments and lead to a decrease in the motivation of workers. For anyone who seeks to rationalize the processes in production, the listed seven hidden losses are the worst enemies.
It is necessary to identify and then eliminate these losses.
Loss of overproduction
Overproduction losses occur when we produce more than is necessary. Lack of planning, large backlogs, large changeover times, insufficiently close contact with the customer (consumer) (this interferes with the understanding of their constantly changing requirements) leads to an increase in the duration of production cycles. We worry that our customers may need more, and as a result, we suffer the cost of producing goods and services that are not being used or cannot be sold.
To eliminate the loss of overproduction, it is required to find processes that during which more is produced than the customer “pulls out”, and therefore excess products require additional measures for their storage.
Release more products faster or earlier than required for the next production step is considered the most dangerous form of waste in lean manufacturing, as overproduction creates and hides other waste, such as inventory, defects, and excessive movement.
The introduction of pull production is aimed at preventing overproduction, which is also one of the three most important components of the production system. "just in time".
Waste of waiting time
This type of loss occurs due to operator downtime during machine operation due to equipment malfunction, due to untimely receipt of the necessary parts, etc. Losses can be eliminated by leveling and synchronizing individual processes.
Losses in transit
This type of waste is associated with the movement of parts and products unnecessarily, for example, from production to the warehouse of the next production stage, instead of locating the next stage in close proximity to the previous one.
It is necessary to build and analyze the flow of transportation of materials, parts, etc. Waste is reduced by minimizing the physical distance of material transport and vehicle movements by zoning and replanning.
Waste due to over-processing
These losses are associated with the performance of unnecessary or excessive processing, as a rule, in the production of products and services with higher consumer qualities than the consumer demands. Adding features and functionality that have no customer value does not improve the product and the process that produces it. Lack of information about how a consumer uses a particular product often contributes to the addition of unnecessary features and functions to the product, which, in the opinion of the manufacturer, are necessary for the consumer (however, this is not known exactly). Waste can be reduced by identifying what features and functions the consumer really needs and what the consumer is willing to pay for.
Stocks
Waste due to holding more inventory than is necessary for the well-planned operation of the pull system. Excess inventories are tantamount to freezing capital, reducing the return on investment in labor force and raw materials.
It is necessary to identify excess production capacity, excess stocks of raw materials, work in progress or finished goods with a turnover of less than 10 times a year. Apply just-in-time and tag (kanban).
Travel losses
Losses caused by the movements of the operator, performed by him outside the scope of productive work or in which there is no need, for example, the search for parts, tools, documents, etc. While most manufacturing processes were originally designed to minimize unnecessary movement, this is generally one of the largest sources of waste that occurs unnoticed and leads to failures.
Losses can be reduced by analyzing value stream maps and/or physical flow maps for each process.
Losses due to fixes
This type of loss occurs when there is no reliable control system and built-in error protection.
Every time we make a mistake while working with a product and pass it on to the next step in the process or to the customer, we put up with rework as an integral part of the process. We lose money twice every time we remodel and repair.
Losses can be reduced by improving visual inspection. Development of more complete standard operating procedures, implementation of built-in error protection system and "fool protection" system (for example, photocells, stop in case of incorrect installation of a part, etc.).
5S workplace organization system.
The organization of the workplace using the 5S system involves the implementation of the following activities:
Sort: Get rid of what you don't need
Keep order: define a place for each thing.
Contain workplace clean.
Standardize procedures for maintaining order and cleanliness.
Improve order. Encourage maintenance.
System 5 S is a method of organizing the workplace, which significantly increases the efficiency and controllability of the operating area, improving corporate culture, and saves time.
Some lean advocates introduce a sixth concept - develop and maintain safety procedures in the workplace
3. Quick changeover (SMED).
Today, customers are interested in the fast and high-quality execution of his order. Therefore, faster changeovers on smaller, more flexible changeover equipment make it easier to respond to customer requests and reduce the cost of holding large inventories while waiting for the right orders.
Bo , Larger parties demand more , more stocks. Bo , Larger stocks freeze more , higher amounts of money and make customers wait longer. Thus, large batches reduce the ROI (ROI).
The process of reconfiguring production equipment to move from the production of one type of product to another in the maximum possible a short time. The main ideas of quick changeover are as follows (figure 5.1.):
allocation of internal changeover operations that can only be performed by stopping the equipment (for example, installing a new mold),
allocation of external changeover operations that can be performed during the operation of the equipment (for example, delivery of a new mold to the machine)
subsequent transformation of internal changeover operations into external ones.
If most of the former internal operations are transferred to external ones, then they can now be performed before and after the actual changeover. The next step is to reduce the time for the remaining internal operations. The developer of the quick changeover tool is Shigeo Shingo (1950-1960) for press changeover. He believed that the changeover time should be measured in minutes as a single number, i.e. be less than 10 min.
4. Just in time (JIT) system.
A production system that produces and delivers only those items that are needed at exactly the right time and in exactly the right quantity. Just in Time uses three key elements: pull production, takt time, and continuous flow. While the Just-in-Time system is simple, it requires strict discipline to implement.
Takt time equal to the available production time divided by the volume of consumer demand.
The purpose of takt time is to bring the rate of production exactly in line with the rate of consumption. It determines the "pulse" of the lean manufacturing system.
Process speed is usually measured by takt time. (for example, the enterprise operates 480 minutes per day, consumer demand is 240 pieces of this product per day. The takt time is 2 minutes.)
Takt time was first used as a control tool in Germany in the 1930s in the aircraft industry.
Continuous flow- production and movement of a single product (or a small homogeneous batch of products) through several stages of processing with the greatest possible continuity. At the same time, at each previous stage, only what the next stage requires is done.
Figure 5.1.
Schematic diagram of quick changeover
Continuous flow is also called the flow of single products and "made the product - handed over the product." In a continuous process, WIP between process stages and/or at their starting points is minimized.
5. Tag (kanban).
A tag (kanban) is a communication tool that gives permission or an indication for the production or withdrawal (transfer) of products in a pull system. There are six rules for the effective use of the tag:
Processes - consumers order products in full, indicated on the tag.
Supplier processes produce products in the exact volume and sequence indicated on the tag.
Without a tag, products are not manufactured or moved.
A tag is always attached to all parts and materials.
Defective parts and parts in inaccurate quantities are never transferred to the subsequent production stage.
To reduce inventory and discover new problems, you need to consistently reduce the number of tags.
The use of Kanban tools is expedient in the organization of production, inventory management and organization of logistics at the repair and industrial structural divisions of Russian Railways.
6. Mistake prevention.
This method eliminates the very possibility of making a mistake. Workers, engineers and managers themselves develop procedures and devices to prevent errors where they may occur. Preventing errors where and when they occur is the most economical and cheapest way to avoid problems.
Control that uncovers errors but does not provide feedback, is called evaluative.
Informative control– control that provides data and information about where and when errors occur. It can be useful to prevent future errors.
Control that detects, corrects and/or prevents errors before they occur where they could or have occurred is called source control. Only control at the source prevents errors from passing to the next stages of the process and provides data to prevent errors or to correct them. Source control is also called in-process control.
7. Mapping the value stream.
A holistic view of the process of manufacturing a product gives an overall picture of the value stream, the totality of all its components.
A value stream map is a simple diagram that depicts each step in the flow of materials and information needed to fulfill a customer's order.
Most processes begin with a request to perform some action or supply a product and end only with the delivery to the consumer.
Value stream mapping covers all processes, from the shipment of a product to the receipt of raw materials or a request for an action.
Mapping the value stream will allow you to identify the losses hidden in the process, often making up a large part of the cost of a product or service.
On the way from the application to the delivery of goods / services, the material flow passes through many workers and equipment (machines). The flow of information also moves from the initial request for a product/service to acceptance by the customer.
Value stream mapping includes a description of both material and information flows.
First of all a map is drawn up of the actual, current state of the value creation process.
Then with the help of this map, a vision of the process is formed, taking into account improvement - a map of the future state of the value creation process.
8. Continuous improvement (kaizen)
Value Stream Mapping
Value stream mapping is a fairly simple and visual graphical diagram depicting the material and information flows necessary to provide a product or service to the end consumer. The value stream map makes it possible to immediately see the bottlenecks of the stream and, based on its analysis, identify all unproductive costs and processes, and develop an improvement plan.
Value stream mapping includes the following steps:
1. Documenting the current state map
2. Production flow analysis
3. Create a future state map
4. Develop an improvement plan
Thread of Ariadne
Customer value is a fundamental Lean principle, according to which the goal of deploying a Lean system is to identify and eliminate waste that does not add value to the product and / or service from the point of view of the client. Accordingly, if you decide to take the path of Lean production, then you just need to learn to see the totality of interrelated and interacting processes of the company through the eyes of your client. But how can this be done? How simply and clearly can you depict the relationship of material and information flows of the company, and how to analyze them for losses?
If we look at the company in terms of the traditional approach that describes it as hierarchical, functional structure, then we will see a real labyrinth, which is completely impossible to evaluate from the point of view of the efficiency of functioning. Therefore, we need a kind of Ariadne's thread, which would allow us to link into a single picture all the links in the production chain to create the final product. Such a thread is the process approach to the description of the company's activities. A process is a certain logical relationship of actions to obtain the final product and / or service. It is logical that it is impossible to see all these actions at the same time, since they are separated in time and space.
Therefore, in order to analyze the entire value stream and its constituent processes, an applied methodology is needed that allows one to carefully study and accurately describe each of the processes, while indicating their relationship. You can describe the processes and their interrelations in words (which, in fact, is done in factory regulations that are extremely difficult to unambiguously understand), but this will increase the likelihood of errors when analyzing the flow, since different people understand words differently, but you can describe the same thing schematically , using visualization tools. That is why we need a tool that allows us to create a visual description of the processes, taking into account their relationship. In Lean manufacturing, such a tool is a value stream map (sometimes it is referred to as VSM - this is an abbreviation for the English Value Stream Map).
Value Stream Map (VSM)
A value stream map is a fairly simple and visual graphical diagram depicting the basic indicators and the relationship of material and information flows to create the final product and / or service. The use of the VSM tool is key to deploying Lean in a company. First of all, the value stream map allows the client to see both the entire value stream “from door to door” and individual processes. This allows you to identify problem areas associated with losses: for example, activities that do not create value from the point of view of the client; excess stocks of raw materials, work in progress and finished products; loss of employee time; uneven and overstressed value stream; incorrectly organized system of planning and organization of production, etc. Sometimes when constructing flow maps, consultations are held with consumers in order to identify their actual requirements and wishes, so that then the principles of production organization can be agreed in accordance with these requirements. After all, one cannot focus only on one's own opinion about the needs of the customer: it is known that quite often the company produces more products than the customer actually requires, while endowing these products with properties that are not of value from the point of view of potential consumer. As a rule, it turns out that the client is interested in real-time value addition, which is only 2-5% of the total production time of the product and/or service.
Future state of the value stream
It should be remembered that the current state value stream map itself is not an end in itself of the VSM methodology, it is a flow analysis tool that provides a common language for decision-making at all levels of the company and for their further implementation. Therefore, having built a map of the current state, in no case should we stop there. The next step in the mapping work is to assess the state of affairs in key areas of the flow, identify the main problem areas and develop optimal solutions for their improvement. After analysis, a future state map is created showing improvement options to achieve more high level flow efficiency at some point in the future. In parallel, a detailed implementation plan for the improvement changes is being developed.
Sometimes it makes sense to build a value stream ideal state map that defines a vector of incremental stream improvements. This map shows the state of flow that can be achieved with a comprehensive deployment of Lean.
Thus, working with flow maps allows you to increase the efficiency of the entire company and avoid common mistakes selection of Lean tools and areas of their use, which usually lead to the creation of ineffective isolated areas of improvement.
The culmination of value stream mapping is the integrated work with all production and administrative flows in the company, as well as the analysis of interactions with suppliers and customers, which allows you to launch and further develop the principle of continuous improvement throughout the entire value chain, both inside and outside the company , - and this is extremely important, since in the conditions of the modern market it is no longer individual manufacturers that compete, but chains of suppliers and manufacturers.
A reminder on building a customer value map
1. Selection of a product for mapping (the product must be produced at the time of mapping)
2. Presentation of the observer to the management of the workshop, workers to clarify the goals of the work and establish contacts
3. Preparation for mapping: print out the necessary forms, map paper, pencils, stopwatch, etc.
4. Walk downstream from the consumer of the product (may be a warehouse of finished products or an assembly site), production, a blank shop and to a warehouse of metal or a warehouse of blanks
5. Build a "Map of standardized work" application No. 1 reflecting the actual movement of the part through the workplace, site, workshop, plant (Spaghetti Diagram)
6. Take measurements for each operation and fill out the "Time Recording Card" application No. 2
7. Based on the measurements, fill out the form "Time Recording Card" Appendix No. 2 (list of operations, average production time for operations, equipment used)
8. Fill out the form "Time Recording Card" Appendix No. 2 for all processes (cycle time, processing time, break times, etc.)
9. On a sheet of paper, arrange the operations in accordance with the execution of the process
10. Determine the number of blanks and finished parts located at the workplace and mark on the sheet in the form of a triangle and indicate the quantity
11. Arrange the movements on the map in the form of an arrow and indicate: distance, time and method of movement (crane by beam, on a trolley, etc.)
The inventory holding time is determined by multiplying the amount of inventory by the cycle time of the next operation.
12. At the bottom of the map, mark the timeline and plot value-adding and non-value-adding time
- non-value-adding: movements, stocks, expectations, etc.
- adding: part processing time
13. At the top of the map, indicate the information flow.
14. Fill in the table on the sheet "Indicators of the current state."
15. Analyze the current state map to identify bottlenecks (places to eliminate losses) and designate them as a star
16. Based on the analysis, construct a future state map taking into account goals (reducing inventory, increasing equipment utilization, reducing area, takt time, etc.) and fill in the “future state indicators”.
17. Build a "spaghetti chart" of the future period
18. Coordinate the preliminary version with the management of the workshop and the project curator
19. Compile activities for a step-by-step transition from the current state to the future, define milestones with an indication of the deadline
20. Calculate economical effect for each item
21. Finished project get approval from the project manager
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EXAMPLE
Value stream map: what is a stream product?
Vrungel: Excuse me, Lom said that you know how to understand cards?
Fuchs: Oh, that's all you want. Cards are my bread. Only not marine, but playing cards.
"The Adventures of Captain Vrungel"
For the first time when I received the task of “build a flow map”, I thought: simple as shelling pears. I know how to designate different details of the production process, I know where to start and how to continue ... After all, I drew business processes for enterprise standards in my “past life”, and here are other icons and certain conditions. And that's it.
The fun details began when clients asked, “How detailed should the map be drawn?” This is where it started… Over the past few years, quite a lot of such simple and complex issues related to flow maps have accumulated…
But in order not to be inconsistent, I would like to start with another question.
In fact, the first "pitfall" awaits at the moment when you are trying to determine which product to reflect in the stream.
What is a "product"? Let's start with definitions.
Value-Stream Mapping (VSM)
A simple diagram depicting each step in the flow of materials and information needed to fulfill a customer's order. (An Illustrated Glossary of Lean Manufacturing, ed. C. Marchwinski and D. Shuk, Alpina Business Books, 2005, p. 51)
Not very clear. But, logically, a value stream map depicts a value stream. Let's get the flow definition:
Value Stream
All the activities, both value-creating and non-value-creating, that allow a product to go through all the processes: from concept development to production launch and from order acceptance to delivery. These activities include the processing of information received from the client, as well as operations to transform the product as it moves to the client. (An Illustrated Glossary of Lean Manufacturing, ed. C. Marchwinski and D. Schuk, Alpina Business Books, 2005, p. 78)
There is already a link to the product here. But there is no definition of the product in the glossary - too simple a concept to put into a dictionary. However, it is clear that if the flow includes all activities from conception to release into production and from order acceptance to delivery, then the product must be suitable for the end consumer - i.e. it must have value of its own to those to whom we sell it.
I omit the definition of value, otherwise we will go too far to the side.
So with products in conventional production, the first questions begin when building a value stream map. What is considered a product of the flow - one product, a group of products, on what basis to group products, and so on ... In fact, everything starts even earlier - after all, each product has its own consumer, which means that you can only group products that have the same consumers. But this is again a departure.
Not many industries make just one or two or three similar products. If you work in such a production, you are in luck. But what if there are several thousand models and partly their production is interconnected - if you want to make one “Product A”, then you need to make three “Product B” at the same time?
Suppose we draw a map of the production of natural granite tombstones. A large block of granite is taken, sawn into pieces, some tombstones are obtained, others only curbstones. And from very small ones - a paperweight. A paperweight is not only a piece of granite, but also a small cast-iron figurine-handle, which is made on separate equipment. And the grinding of paperweights, tombstones and pavement slabs is done on the same equipment. How to draw in this case the flow of production of tombstones?
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It's not a map yet, it's just a sketch, and a lot of questions have already arisen.
The ideal solution is to unravel the tangle of routes, separate product groups from each other, and launch individual products separately - first “Product A”, then, if necessary, “Product B”. And as much as necessary, and not as much as it turns out.
But sometimes such an ideal solution requires a revision of the concept of production, or even a complete replacement of the machine park. What to do?
Let's remember why we need a value stream map = Value Stream Map. Here are the two main goals:
1. See the entire flow as a whole (and enable managers to speak the same language about the problems of different “stages” of the flow).
2. See all the losses that are in the stream.
We already know that we have a "tangle of problems" associated with cunning routing and that this tangle needs to be unraveled. A detailed map will be useful for this, but the first steps can be taken without it.
Then what can be sacrificed by the “ideal” so that the card still carries value?
Exactly the definition of "product" or, to be more precise, "base product of the flow map".
Suppose we take something atypical as the "basic product", or even not a complete product, but some part of it, not caring about how the production of the rest of this product proceeds until the moment they are combined.
Will we be able to see the entire flow of this "atypical product" or this part of some product?
Take, for example, the base product of the paperweight. And draw his route. What will happen? Operations related to the processing of "pavement slabs" will fall out of our attention. But at the same time, we will see all the delays associated with the stages of separating the pieces of paperweight from the total granite mass, we will see that before grinding the semi-finished products wait in line, and before joining the figurine-handle, the batches of paperweights are crushed into pieces to match the batches, by which figurines are cast.
Will we be able to see the entire flow from start to finish? The part that is connected with the production of paperweights - yes. The rest - no. Will we be able to see the losses - yes, those associated with the production of paperweights. The rest - no. Is this card useful? There is. How dangerous is this card? By optimizing part of the flow, we risk creating even more losses on the scale of the entire flow. How to reduce this danger? Seven times to measure those changes in this stream that can affect everything that remains "beyond".
By deciding to always sand semi-finished paperweights first, we are slowing down the production of "tombstones" and "pavement slabs." Such decisions need to be carefully analyzed.
However, some compromise needs to be found. Sometimes, in order to be closer to reality, you have to deviate far enough from the "academic" definitions of a flow or a product. For example, when describing the production of cabinet furniture, we could not isolate the flow "cabinet" or "cabinet", because the entire weekly volume of production is cut simultaneously from the same laminated chipboard, and the details of different pieces of furniture are mixed in order to reduce unused residues of laminated chipboard (according to In fact, the task of cutting laminated chipboard is a combinatorial task - how to arrange the parts according to the sheets in such a way as to spend as few chipboard plates as possible, and so that as few remnants of the plates as possible go to waste). As a result, the flow map was built for only one of the detail groups. The overall picture of the flow did not turn out, but the measurements of indicators for the selected group of parts made it possible to document the main flow problems and refocus the work on their solution.
Determining the product of a stream can be a very tricky issue, and changing the process of creating a product can lead to a revision of the understanding of flows and, accordingly, to a revision of the grouping of products, and therefore a change in the answer to the question "what is the product of this stream?"
Sometimes you meet a person who has not heard anything about lean manufacturing and asks to briefly explain what it is. In addition, there are people who believe that lean manufacturing means signing everything everywhere and applying floor markings.
It turns out that it is difficult to briefly describe a topic that you can talk about for a week in a row without stopping. Moreover, clever words(as in Wikipedia) anyone can explain, but I'll try simple.
1. Customer orientation
3. Organization of production cells
Live looks like this:
Purpose: to increase labor productivity. One person can achieve such perfection that he can service several pieces of equipment at once.
4. Reducing the duration of the release of the order
All we do is keep track of the time between the customer placing an order and getting paid for the work done. We shorten this period of time by eliminating waste that does not add value ( , 1988).
It is necessary to ensure that as little time as possible passes from the moment a client submits an application to the moment when he receives his order.
In this process, you need to focus on two concepts: cycle time and takt time.
Cycle time(duration of order release) is the duration of the product through the entire stream from start to finish.
Takt time is the frequency at which finished products leave the line. The target takt time is determined by market demand (for example: we need 2 cars per day).
Mass production has a very short takt time (shoots like a machine gun), but a very long cycle time (each of the units is produced for a long time). in addition to freezing material assets in the form of work in progress, this also greatly reduces the rate of production of rare brands of products.
5. Flexibility
In mass production, equipment readjustment is extremely rare - the equipment produces parts in gigantic batches. Lean manufacturing tends to produce parts in small batches, so the equipment needs to be retooled frequently. That is why it has a very developed tool
6. Elimination of waste
In order to shorten the cycle time, waste is eliminated. Waste is anything that does not add value to the final product. Profit is increased by eliminating losses in production.
Types of losses:
- Overproduction;
- excess inventory;
- Expectation;
- Transportation;
- moving;
- excessive processing;
- Defects;
- Unrealized potential of employees.
7. Intra-shop logistics
The value stream, as well as supply flows, should move in the same direction whenever possible, excluding return and crossing flows. The length of travel paths should also be as short as possible. To do this, use the "Spaghetti Diagram" tool, with which we analyze all movements, and then decide how to optimize them.
8. Everyone involved in the improvement process
In order to eliminate 8 types of losses, all employees of the company, headed by the first person, must constantly deal with this. is the key to success.
This is very helpful for getting involved:
This will require a waiver in favor of open acknowledgment of problems. Refusal to solve problems by replacing people or by "finding and punishing those responsible."
Otherwise, your improvement process will break down, causing your employees to .
How it looks in practice:
Or like this:
The key feature of improvement is continuity. You can not rebuild the enterprise, and then do not return to this issue. A project is something that has a beginning and an end. And the process of improvement should be a vector.
How often do you need to train to be an athlete? Constantly. How often do you need to improve your skills to be a professional? Constantly.
Also with production. The Japanese are ahead of the planet in this regard and have a cornerstone: continuous improvement. Non-stop for decades.
How the Japanese think of evil: daily work + improvement
How the Japanese Think Right: Daily Work = Improvement
Improvement must be continuous. You can’t do something healthy once and live to 100 years. The right way of life must be maintained throughout life continuously.
More about improvement:
Cultivation builds up a certain routine:
If you make transformations and do not return to this issue anymore, then this is what will happen:
Also:
9. Go to gemba (come and see)
The most important principle of improvement and involvement. It lies in the fact that the bosses should not be engaged in the development of the enterprise from the offices. They have to go to the workshop and watch how the work is done. Or go and look at the place where the marriage takes place. Look for the cause of it. The Japanese boss always goes to the front. Where value is created.
Arriving at the place of value creation (gembu), you need to look for the root causes of problems. Do not pull the tops, but dig to the very root. To do this, there is a method "5 Why?". 5 times or more in a row by asking the question "why?" to a worker on the site, you can find out "where the legs grow from." And take action. More:
This is about the value stream. In general, problems should be looked for not only in the gemba, but also in the administration.
10. Process Oriented, Not Result Oriented
We can be praised if you somehow deceived the system and got out of a momentary problem. I poked parts from some other order (which will be shipped in 2 days, not today), or manually got into the priority of the work of the metal parts manufacturing site for remanufacturing some parts lost on your order that is shipping today.
The order was shipped with sin in half, and all such "fuh!" exhaled. Now we need to figure out why this happened on this order. How the manufactured parts were lost, and why the purchased ones did not arrive on time. But wait! We have just picked up parts from an order that will ship the day after tomorrow! Now we need to urgently think about how to ship it. In addition, we interfered with the priority of the metal section, and it is now working with a delay, and something urgently needs to be done about this too! Therefore, there is no time now to investigate why this happened. And then, yes, it did work. The result is there. And this is the most important thing! (No)
In lean manufacturing, it is necessary to constantly improve the process, and then it will already give a stable result.
More:
11. 5S system
5S is very useful for everyone's engagement, as well as for increasing productivity. When we got rid of everything unnecessary, put all the items in their places, signed their places of storage and monitor cleanliness and order, this greatly rebuilds people's minds. Sets them up for improvement. Also, people who do not want to take part in this become very noticeable.
In Japan, no one has ever shied away from "improvement for the sake of improvement" without direct monetary gain. All this creates a philosophy, creates a spirit. Not everything is measured in money. There is also
More:
12. Refusal of mass control
Refusal to mass check products at the exit, as well as the refusal to put a QCD employee after each machine. Instead, the assignment of duties with verification to the workers themselves in the subsequent stages of the work. This is only possible in a culture of cultivation, where the perpetrators are not punished or fined, but simply try to find out what caused the marriage and eliminate the possibility of marriage in the future. For example, by introducing methods to protect against unintentional errors (Poka-yoke):
Then the workers will not be afraid to report defective parts to each other, and QCD employees will not be needed in such numbers.
This is better than checking all products at the very end, because in the end, much more resources have already been spent on it than if the marriage had been discovered at the earliest stages. Therefore, if a marriage occurs in one of the sections, the conveyor is stopped until they find out what is wrong. In order not to drive the marriage further. The Japanese were even the first to come up with a technology that stops equipment automatically when a marriage occurs.
13. Standardization + on-the-job training + supervision
Improvements are pointless if there are no standards in the workplace. Because if there is no standard, the system quickly degrades.
You need to standardize operations like this:
Once the standards are set, best experience should be replicated through training:
Then the implementation of the standards will need to be monitored: (parallel control structure)
14. Visualization
In order for engaged employees to improve processes, processes must be visual, understandable, and standardized. Everything should be visualized and transparent and marked. In muddy water, it is completely incomprehensible what is happening and how everything works, so there are no ideas how to improve it. No loss visible. The goal is for any person, having come to the site, to understand without asking questions how everything works here, how it should work and whether there are any violations.
The visualization looks like this:
15. Statistical Office
Lean manufacturing is based on analysis and facts in its decisions. Facts are statistics. Management must make decisions based on production statistics.
Discussed in detail in the book "7 Tools for Quality Management" by Hitoshi Kume
The main tool for identifying losses. Heavy artillery, so to speak. We can say that this is a huge photo of the working day of the whole process. We sketch everything that is done. We fix time, information flows, number of personnel in operations, downtime, defects and other important information. Based on all this, we make one big map, contemplating which we are looking for opportunities for improvement.
On the wall is an archaic method. It is possible in Excel.
17. Total Equipment Maintenance (TPM)
In order for the equipment to work without failures, it must be monitored. TPM contains the care of the equipment (according to the schedule), as well as the visualization of this process. The equipment must be kept clean, as while we wash it, we find various breakdowns and leaks. Cleaning, lubrication, checking, tightening occur according to the schedule and are described in the standards located on the machine itself.
Example:
This book is for the more experienced thrift:
The book of the man who created the Japanese quality:
As it was in the USSR before Toyota:
A book consisting of reviews of books about BP:
The company focuses on increasing customer value and eliminating non-value-adding (waste) steps. Value stream mapping (VSM) is used in companies that have adopted a lean philosophy.
This map is plotted and then analyzed for activities that add and do not add customer value product, as well as separate steps in information flows and processes. In other words, such a map clearly demonstrates which activities increase the consumer value of the product, and which do not. Due to its rigid structure, this method often helps to significantly optimize the work and identify the activities that are needed for this.
When to Apply the Model
VSM is applied, as already mentioned, in a company where the philosophy of lean is widespread, in order to identify opportunities to reduce the overall production cycle and exclusion of activities that are redundant, unnecessarily costly, or do not add value to the product. The mapping of such processes involves the use of standard symbols and symbols (for more on this see Rother and Shook, 2003) showing material flows and other important data (eg inventory levels, processing times, lot sizes). This map serves as a starting point for designing the company's desired future value stream, which is inherently lean.
How to use this model
The first step in VSM is to map the current state of affairs. The results of the current material flow analysis provide information on value-adding and non-value-adding activities (eg, machining time, wasted space, rework, distance traveled, and inefficient areas).
In the second step, the information obtained from the current state map is used to map the future state of affairs, in which all losses are eliminated and the number of non-value-adding activities is minimized. During this phase, a number of questions will likely need to be answered.
- What is "takt time"?
- Is it possible to ensure uninterrupted production?
- Is it possible to control production with a "pull" system?
"Takt time" (from the English takt-time) - the time of production, divided by the speed with which the consumer requires the receipt of goods, i.e. if the consumer wants 100 units of goods, and the factory works 400 minutes a day, then "time beat" equals 4 minutes.
During this phase, you must always remember that the production system meets the needs of consumers and fully satisfies them, and for this, processes must be flexible.
The third and most important stage is to bring the production process into a state that corresponds as much as possible to the desired one. After that, the whole planning process can start again.
A step-by-step plan might look like this:
- Find out which product commodity group) or a service (a set of services) must be analyzed. Form a team of people responsible for the processes and employees who are involved in different parts of the processes.
- Analyze the current state of affairs, and then state it in the form general scheme processes.
- Collect the data needed for the overall process diagram (for example, the total volume of production on the production line, total time the passage of the product along the entire production line, the number of employees employed).
- Formulate the essence of the ideal process, based on the needs of consumers. (In this step, use parameters such as minimum WIP, reduced set-up times, and a list of improvements that need to be made to arrive at an ideal future state of affairs.)
- Make a plan of improvement actions that need to be completed in order to get to the future state of affairs. This plan should take into account the priorities set for different types improvements: actions to be performed by specific specialists; clearly defined time parameters for the passage of the entire path; sponsor participation.
- Track progress towards a given goal. After reaching it, start again from step 1.
conclusions
VSM is about more than just eliminating waste. It also helps to achieve equipment load balancing. The main goal in applying this method is to use processes to create exactly what the consumer wants to receive. Therefore, we must begin with the study and evaluation of consumer requests and wishes. The data required for value stream analysis may not always be available or may not be available at all, including because such data is not always systematically collected or because the company first decided to analyze its management process in this way. Due to additional data collection, the analysis may take longer than originally planned.
There is one more important condition to consider: everyone prefers a consistent way of working, in which the designed ideal process leads to the desired results. In words, all this sounds simple, but in practice there are often serious problems associated mainly with the fact that people are used to a certain freedom in doing their work. Because of this, sometimes you have to resort to another option. But instead of improvising on the basis of existing methods of work, it would be better to think about how these methods could be constantly improved.
Determining the desired future state of affairs is an important step: its results become the starting point for further improvements. The Action Plan sets the overall direction and shows the steps to be taken to achieve the desired results. However, the new situation often requires new rules and sometimes new behaviors. If these two components are not well thought out and properly included in the plan (and not forgotten in its implementation), there is a risk of a return to the previous state of affairs. If the subsequent steps are not carried out as they should be, mapping the present and future states of affairs will be a waste of time.
Authors: Panina F.Yu., specialist in the development of the production system and quality management system of Wismuth JSC, Fedoskina L.A., Associate Professor of the Department of Quality Management Mordovskiy state university them. N. P. Ogareva.
The functioning of the lean manufacturing system is based on effective application interrelated set of special tools and methods. The most complete set of lean manufacturing tools includes such methods and approaches as Kaizen, 5S-"Ordering", SOP procedures, TRM equipment maintenance system, quick changeover SMED, JIT (Just in Time) system, Kanban and POKA YOKA .
At the same time, preventive attempts to introduce individual or several tools (usually 5S, TPM and SMED) do not give the expected results. This is due to the fact that after their hasty, unprepared and therefore unreasonable implementation, the main production problems are not solved:
- there are downtime due to waiting for the delivery of materials and components to the workplace;
- the areas occupied by finished products, stocks of materials and components are not reduced;
- there is still a shortage of means of moving components and materials;
- there is an untimely production of products.
What is the reason, and how to achieve an increase in the efficiency of the entire production? In order to get an effective result from the implementation of lean manufacturing tools, one must first try to see the entire process of creating products in terms of processes that create value and processes that do not create value (waste).
Losses- useless repetitive actions that should be eliminated immediately. For example, downtime waiting or warehousing nodes.
Detect all losses building a value stream map- VSM. It is a graphic representation of the entire production process.
Value stream mapping starts at the last stage of production and works backwards until the start of the production cycle, and may even include the process of product development and the purchase of material for production (it all depends on the number of problems in production). Each section is marked with:
- cycle time of value-adding operations;
- cycle time of operations that do not bring value (time of control operations, equipment changeover time, waiting time for materials and components, waiting time for information, time for transporting products, etc.);
- the number of products in work in progress;
- the amount of stock;
- the number of operators performing the operation.
It is desirable to evaluate all indicators in monetary terms for carrying out financial analysis production costs.
Mapping work is carried out directly in those areas where the process is carried out. Experience shows that the most convenient way to represent the value stream is to draw an image on whatman paper, preferably with a pencil, so that amendments and clarifications can be made.
Mapping a Value Stream with a Case Study
As initial data we have:
In workshop No. 1, the part is subjected to 3 processing processes at 3 workplaces.
At workplace No. 1, the part is cut to size.
At workplace No. 2, the part is being turned.
At workplace No. 3, the part is milled.
In workshop No. 2 at workplace No. 4, the part is assembled in assembly unit and transferred to the warehouse of finished products.
The described procedure for moving the workpiece is shown in Figure 1.
Based on the methodology we previously defined, we start mapping the value stream from the warehouse of finished products and end with workplace No. 1. The data collected during the analysis are recorded in the appropriate table (Table 1).
As the data in Table 1 show, the total duration of the production process for processing a part is 69,700 seconds. The process consists of fifteen steps. Note that the operational time, that is, the time of creating the value of the part, is 4,150 sec. In percentage terms, this value is only 5.59%! This means that most of the process is unproductive. The production losses are so great that the process under study has a clear need for optimization in time and space.
The most significant overhead occurs during the storage operation, which lasts 56,000 seconds. and takes 80.3% of the total process time. The share of this category of production losses in the total non-productive time is even higher - 85.4%. Thus, it is during the storage of components and finished products that an unreasonably long time is spent, which makes the processing of the part irrational and of low value.
All this indicates that there is a super-inefficient organization of the production process for manufacturing the part in question. The irrational placement of jobs during the execution of technological operations does not allow obtaining a high value of the production process for processing the part in question.
On this basis, a value stream map is compiled with the parameters of the future state of the manufacturing process for processing the part. When building a map of the future state, it should be taken into account that it is necessary to reduce as much as possible the identified losses in the form of unproductive time spent, material resources and spaces. Therefore, at this stage, the best desirable indicators of all parameters of the production process are developed, which are also reflected in the form of a similar table. In our example, the desired process value parameters are presented in Table 2.
Comparing the values of similar indicators in tables 1 and 2, we note that the total duration of the process was reduced by 59,030 seconds, that is, by 6.5 times! The share of productive time for performing the same fifteen operations of the production process for processing a part increased to 31.86% instead of 5.59%. Thus, the value of the flow increased by 5.7 times.
Among the unproductive costs of the production process, storage time still occupies the dominant role, but its share in common process decreased by 33.44% and amounted to 46.86%. As part of unproductive costs, it will also decrease, and in the future state should be 68.78% instead of 85.4%.
An important achievement of the future state of the production process for processing the part in this example is also a significant reduction in inventory and work in progress - inventory will be only 1% of the current level, and work in progress will be reduced to 8% of what is currently taking place. A significant change in the number of employees employed in the production process - from 15 to 6 operators, i.e. 2.5 times - is another weighty argument in favor of building a value stream map in order to analyze the causes and sources of production losses.
In order to summarize the obtained results, we will build a table of target indicators, in which we will enter the data on the parameters of the current state and the future (Table 3).
The economic effect in the table is not calculated due to the fact that the process parameters were not estimated in monetary terms, so it was difficult to conduct a financial analysis. This requires additional data and may constitute a separate line of research for the production process under consideration.
But here the question arises: due to what changes can such noticeable improvements in the production process be obtained and production losses reduced?
Note that there is no single correct answer to such a complex question. There is simply no single recipe for success for organizations that optimize their manufacturing process based on value stream mapping. Just as each organization is unique in its essence, so are the solutions for streamlining and streamlining the flow.
In our example, such significant results were achieved due to the fact that all the workplaces involved in the processing of the part were lined up in a U-shaped cell, which was geographically located in shop No. 1. Figure 2 clearly shows how the spatial arrangement of workplaces has changed, as a result, it became possible to reduce losses during transportation and storage.
As can be seen from Figure 2, in the cell, three operations - cutting, turning and milling - will be performed by one operator. Due to this location technological equipment and workers have the opportunity to reduce the time to move the part from one workplace to another, the time of temporary storage of the part in the warehouse of components, the number of work in progress, reduce the number of operators involved in the production process, reduce the area for a further increase in production volumes.
For a visual comparison and structural characterization of the time of operations that create value, and the time during which value is not created, diagrams are constructed corresponding to the current and future states. The considered option for changing the production process is presented in the form of two pairs of diagrams in Figure 3.
They show that in the current state, the total duration of the process consists almost entirely of non-value-creating time, and only a small fraction of the value-creating time. In the future state, unproductive time is only slightly more than value creation time, and the total duration of the process is significantly reduced and its time structure is more rational.
However, only the creation of a U-shaped cell was not enough to obtain the presented results. Specialists needed to carry out a number of complementary activities and make appropriate management decisions.
To reduce the number of operators, it will time the work of operators at all workplaces, highlighting the manual work of the operator and the machine time of the equipment. Then an "operator work standard" was developed, taking into account that the operator must perform manual work simultaneously with the processing of the part on the equipment;
To reduce the cycle time for performing operations, a 5S system - "Ordering" was introduced. Practical guide with instructions and checklists ;
Elements of the SMED system were used to reduce the equipment changeover time;
To reduce downtime due to equipment failure, a TPM system is being implemented.
To reduce quality control time, the POKA YOKA approach is applied;
To reduce work in progress, downtime due to untimely delivery of materials, components, JIT principles are used.
Only such a comprehensive solution of production problems will reduce losses in the studied production process and, on this basis, increase its efficiency.
Literature
1. Lapshin V. S. Fundamentals of lean production: textbook. allowance / V. S. Lapshin, L. A. Fedoskina, E. A. Lyamanova, D. V. Rodin, E. E. Rodina, I. V. Filippova. - Saransk: Publishing House of Mordov. un-ta, 2011. - 168 p.
2. production system Toyota. Moving away from mass production / Taiichi Ohno; Per. from English-M.: Institute for Complex Strategic Studies, 2005. - 192 p.
3. Learn to see business processes. Value Stream Mapping Practice / Mike Rother, John Shook; Per. from English. - M. : Alpina Business Books: CBSD, Business Skills Development Center, 2005. - 144 p.
