Analysis of material information flow diagram in t

Diagram analysis of material information flow in the process of TPS promotion

TPS (Toyota Production System) originated from Toyota Motor Company in Japan. Its core is to pursue the elimination of all "waste", organize the production and business activities of enterprises in the way of customer pull and JIT (just in time), and form a unique production and operation management system that can quickly respond to market changes

the huge advantages of lean production in the whole process of product development, manufacturing, management and customer service have been recognized by the world business community through the great success of Toyota Motor Company, so that everyone is learning and imitating. Unfortunately, after learning TPS concepts and methods, many enterprises rarely carefully analyze the value stream of the whole product, and soon entered the large-scale waste elimination activities, such as standard operations, 5S activities, small team improvement proposals, JMS activities and 5W1H activities. These improvement and improvement activities can quickly improve part of the product value stream, especially make the macroscopic logistics of the production site smoother and the site cleaner. However, because people do not consider the whole link of the product value chain, do not pay more attention to information flow, capital flow, and other parts of the problem will still lead to a large number of inventories, resulting in the final result is that the cost has not been reduced, or even increased. Even if lean is only partially achieved, the sustainability of the improvement effect will be limited

to promote TPS management mode, enterprises should establish effective production methods in organization, management, supply chain, product development and production operation according to TPS principles, aiming at eliminating all waste that does not increase added value, gradually improve, and then maximize economic benefits and competitiveness. As an effective tool, material information flow graph analysis technology can help enterprises consider the flow of the whole product value flow through the method of mapping, rather than only considering the isolated process, so that enterprises can continuously and systematically improve their whole value flow, and improve their efficiency and competitiveness in the market

graphic analysis technology and method of material information flow

1 Value stream

the so-called value stream is all the activities required by the current product through its basic production process. These activities include adding value to products and not adding value, including the whole process from the most basic raw material stage of products to the delivery of products to customers. For example, the manufacturing of a car includes the process from customer requirements to conceptual design, product design, sample car manufacturing, testing, finalization, production to use after delivery, information feedback and recycling, which requires many workshops, factories and companies

real time mapping and maintaining the completed experimental load waveform 2 Material information flow graph analysis technology

material information flow graph analysis technology is a powerful tool to help analyze the entire value stream. It can turn the entire value stream, which is usually chaotic and complex, into a visual status map of the value stream, making the problems in the value stream appear. In this way, various TPS technologies (standard operation, 5S, 5W1H, etc.) can be applied to eliminate non value-added activities (i.e., waste). This improvement can not only eliminate waste, but also eliminate the source of waste from the overall value stream, so as to improve the competitiveness of enterprises

before the technical description of material information flow diagram, it is necessary to clarify the main steps of diagram analysis and adopt "5W1H method"

(1) who (who): need a person who understands the site and can promote its improvement. This person has the responsibility of leadership. He will lead a team to draw and organize the analysis work

(2) what: generally, we first analyze the products that have the greatest impact on the enterprise according to the 80/20 principle

(3) when: the drawing analyzes the causes of the existing problems, finds out the true causes and establishes the time to improve the process

(4) where: on site, only the data collected on site can truly reflect the status of the value stream

(5) how: what tools can be used to support the found problems and improve them quickly and efficiently

practical application of material information flow chart

1 Definition of pictorial symbols (see Figure 1)

2 Draw the current material information flow chart

next, take the factory material information flow chart in Figure 2 as an example to briefly introduce the application method of material information flow chart analysis

the material information flow diagram analysis is divided into three parts as a whole - three horizontal axes. The top horizontal line is the axis made by information flow, the middle line is the axis made by real logistics, and the bottom line is the axis made by time flow. Figure 2 can connect the three items of information, materials and time that are not related to each other from space, which helps us fully expose and find problems

Figure 2 current material information flow diagram of the factory

volume e requires small customer requirements, as shown in the upper right corner of Figure 2, and the purchase and delivery of raw materials are shown in the upper left corner of Figure 2. Understand and record the information transmission way, mode and frequency of customer ordering, production plan and raw material ordering process, and draw the information flow

as shown in the box below the logistics line in Figure 2, it is also the basic production process in the factory. We include the process that can be carried out continuously into a data box, and we cannot use inventory triangle to separate the two boxes continuously

collect and record the data of each production process and fill it in the data box (including cycle time, type change time, number of operators, equipment operating rate, scrap rate and other data related to process improvement)

note that these data should be the current data collected on the spot by using the TPS three presence principle, rather than some data records or artificial estimates

when understanding the inventory situation, the team should count all inventory (including online WIP inventory), and then record it in the inventory triangle. Note that it is still the result of on-site confirmation of on-site objects based on the TPS three present principle, that is, counting points rather than checking accounts or artificial estimates at the custodian. Convert the inventory (including WIP) quantity into time according to the beat of customer demand, draw it on the time axis together with the production process time data, and calculate the percentage of production process time in the whole time

3. Draw the future material information flow chart

(1) draw the future material information flow chart should follow the principle of seeking

① produce according to the customer's beat (definition of production beat): make the beat of the production process consistent with the delivery of the customer's beat, and realize just in time production

② realize continuous flow as much as possible: eliminate and reduce inventory and waiting as much as possible, so that the production process can be carried out continuously

③ Kanban pull management is used where continuous flow cannot be achieved: Kanban management is used for a wide variety of processes that differ greatly from the beat, such as stamping and welding

④ make the customer's order only be sent to the final process to ensure the consistency of information

⑤ in the process of starting the value stream, the production of multiple varieties of products is evenly distributed according to time to achieve balanced production

⑥ in the process of starting the value stream, the initial pull is achieved by starting the work of a unit. The "power source" of this pull must come from customers

⑦ in the process of starting the value stream, the upstream process forms the ability to manufacture various parts every day. Multi variety and small batch mixed flow balanced production requires the upstream process to improve the response speed to downstream process changes by reducing the type change time and production batch, so as to reduce the inventory of WIP as much as possible

(2) draw the future material information flow chart

the purpose of drawing the current situation of material information flow chart is to fully expose the waste problems existing in the current management in the form of diagrams and calculations, find out the true causes through analysis, and take practical measures to solve them step by step. From Figure 2, we can see that the production and processing time of 825.55min only accounts for less than 4% of the total cycle time of 44.95 days, and a lot of time is wasted on inventory waiting. As shown in Figure 3, the implementation of the improvement process is carried out in the way of PDCA. By analyzing the reasons, the key problems are found, and the improvement plan is formulated and implemented - that is, the principle of TPS is used to eliminate the waste in the product value stream

from the comparison between the current situation chart of factory value flow (see Figure 2) and the future status chart (see Figure 3), we can find improvement points by describing and analyzing the problems existing in the current situation; Through the drawing of the future state diagram, determine the improvement goal; Then, the PDCA method is effectively implemented to achieve the purpose of improvement and improve the efficiency and competitiveness of enterprises

Figure 3 flow chart of material information in the ideal state of the factory

in terms of effect, comparing the current situation with the future state, it significantly improves the efficiency and flexibility of production and meets the requirements of customers to a greater extent: the ratio of processing time to production cycle has changed from

825.55min/44.95 days to 590.4min/11.29 days, which reduces the production time and production cycle. Through the reduction of production cycle, the response time to customer orders has been increased by more than twice, This can greatly reduce inventory; The reduction of inventory means the reduction of working capital, financial costs, product losses and warehouse management costs, which means the improvement of profits

conclusion

through the application of material information flow chart for several years, combined with the application of corresponding auxiliary tools such as 5S, standard operation and JMS, we have achieved the following results in actual production: eliminate more than 50% of the waste process; The cycle time of product production process has been reduced by more than 75%, and the quality level has been improved; Due to the implementation of small batch and multiple varieties, the number of deliveries has been increased, and the logistics cost has increased, but the cost of the entire value stream has been greatly reduced. (end)