The hottest lean production based on APS and MES

2022-08-09
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Lean production based on APS and MES

modern manufacturing industry is no longer a profiteering industry, but has entered the era of meager profits. The product price has been continuously reduced, but the production cost has not been significantly reduced. In order to achieve high profits, it is necessary to reduce costs in all aspects of production management, eliminate all kinds of waste in the production process, and improve efficiency

manufacturing process is the biggest cost consumption center. To reduce costs, we must eliminate waste in each production step, that is, to achieve lean manufacturing process. That kind of "probably" rough production management mode can no longer adapt to the era of meager profits in today's manufacturing industry. Waste of materials, excessive inventory, idle equipment and labor, chaos caused by poor planning, rework caused by quality problems, etc. will reduce the profits of enterprises

the use of information technology is an important way to achieve lean production. At present, the information technology used in the manufacturing industry includes ERP, CRM, SCM, MES, APS, etc. ERP is usually the first information system introduced by enterprises. It is a high-level information management platform, which mainly deals with the basic data of enterprise operation such as finance, orders, materials, etc., but ERP cannot solve the problems of production site. In order to realize the informatization of manufacturing process and comprehensively optimize and supervise each link of production, other information systems are also needed

to realize the informatization of manufacturing process, enterprises should improve from two aspects: planning and implementation. APS is an advanced planning system, which uses software to help enterprises prepare more optimized production plans. MES is a manufacturing execution system, which collects and records various data in the production process and monitors the on-site status in real time. On the one hand, it controls the product quality, on the other hand, it saves various data in production for later tracking

Advanced Planning and scheduling system APS

the basic concept of APS system is to use mathematical methods to optimize production plans, purchase plans, transportation plans, etc., which is part of supply chain optimization software

traditional production plans are prepared manually, and the disadvantages of this method are very obvious. Although many people think that the plan of experienced production management is no worse than that of software, the disadvantages of manual scheduling are inevitable, one of which is the lack of predictability for the future. Because of the amount of data, even experienced production management has strong short-term scheduling ability and insufficient long-term analysis ability. In most enterprises, the production management department only arranges the detailed plan for the future days of tensile testing specified in astmd638 and iso527, and the analysis of long-term demand can only be rough. Therefore, the matching of equipment, staff, tools and other resources with demand cannot be accurately analyzed, and the factory often delays delivery due to insufficient preparation. On the other hand, because the future plan is not accurate, the purchase plan of the factory is often rough, which will cause inventory backlog and increase inventory costs

APS system has two applications, long-term analysis and short-term scheduling. The purpose of scheduling and calculating the demand in the next few months is to have an overall plan for future production, analyze whether various resources can meet the demand, so as to make preparations in advance and reply to the customer's accurate delivery date at the same time

short term detailed plans are used to guide daily actual production. In order for the software to calculate the production plan, it is necessary to describe the planning requirements of the enterprise to the APS system, which is the system model. The model of APS system defines the constraints of scheduling, and the system adopts some optimization algorithms according to the constraints. At this time, it can realize the stepless variable speed experimental machine with several to twothousand revolutions to find a solution. APS model mainly includes several main aspects:

1 Products and materials

2 Production process and procedure

3 Main production resources, including production lines, main processing equipment, etc.

4 What process is used to produce the product, what processes are followed, and what is the processing sequence

5 What resources are allowed for production of each product/process, and the production cycle time of unit product

6 Materials and semi-finished products (BOM) consumed by the product in each production process

7 Auxiliary resources, such as molds, jigs, test instruments, etc., how many are there, and which products/processes need to use these tools

the above is the main content of the model. Different enterprises will have different constraints, and there are many specific constraints in the model. For example, in the injection molding industry, there are color switching restrictions, electronic products have product similarity switching restrictions, and the process operation is more solid, and there is a relationship between before and after and time. The model is to convert the experience of production management into accurate data. The system schedules according to the model, and the scheduling no longer depends on personal experience. The factory can realize the accumulation of knowledge and ensure the stability of the plan.

in the actual project, APS system also needs to obtain the scheduling target data from the outside, that is, demand, inventory, etc. if it is an enterprise produced by work order, it also needs the current work order list. The above data are usually obtained from ERP, which can be obtained by reading ERP output report by APS system. After the scheduling, APS system outputs the production plan report, and ERP reads the plan report as the basis for MRP calculation

the optimization of production plan is the common aspiration of all enterprises. APS system can bring great benefits to enterprises, but unfortunately, few enterprises have introduced APS system. On the one hand, there are not many excellent APS systems at present. In China, most of the research is still in the theoretical stage. On the other hand, enterprise managers have not accepted the concept of using software to prepare production plans. Many enterprise managers believe that the production scheduling of enterprises can only be completed manually, because the plan formulated by the computer is too idealistic, and many human factors and complex situations can not be taken into account. However, the actual production changes frequently, and the plan needs to be changed every day, so the scheduled plan cannot be implemented. However, we believe that an ideal plan is very important for an enterprise. Only by having an ideal plan first, and then tracking the daily changes, can we find the difference between the ideal and the actual, and gradually improve. The combination of automatic production scheduling and manual modification is the correct mode of enterprise production planning

aps system not only realizes optimal scheduling, but also generally provides Gantt chart for users to maintain and modify plans. Gantt chart provides a very intuitive tool, so that users can easily analyze and modify plans and track daily plan changes. Especially for multi process production enterprises, Gantt chart can easily show the relationship between processes, mark the location of bottleneck resources, and facilitate enterprises to analyze production processes and find ways to improve

given the huge differences in the manufacturing industry, it is difficult to find a scheduling system suitable for all industries, but you can consider the industry background of the developer to find a system suitable for a specific industry. At present, some APS systems in China have successful experience in specific industrial fields. For example, Beijing xiaojixing's PRM scheduling system has been applied to the aircraft manufacturing industry, Shenzhen Ritter's planmate scheduling system is applicable to the electronics and injection molding industry, and some foreign products have also entered the Chinese Mainland market. Enterprises can consider the industry experience of software companies to find products suitable for themselves

Manufacturing Execution System MES

manufacturing execution system (MES) is also called shopfloor in the factory. Its core is to collect data from all aspects of the production site, save the data, make statistical analysis on these data, and send the data to people who need to respond slightly. The implementation of MES needs to achieve several purposes:

1 Traceability: when a product is produced, it can be found from the MES system, such as the production process, equipment used, production time, operator, materials consumed (material batch), various condition parameters during production, test steps, test results, etc. That is, from these data, the whole manufacturing process can be reproduced. When quality problems occur, the cause can be quickly traced, including the production batch of source materials and other information

2. Anti stupidity in the manufacturing process: the product is required to go through multiple production and testing processes in a certain order in the manufacturing process. If the previous process is not completed or the test results are unreasonable, it is not allowed to enter the subsequent process. Under the control of MES system, defective products can be prevented from entering the warehouse and entering the market.

3 Real time monitoring: what products are each production line doing now? Is the progress normal? Which line is stopped or delayed? Is the distribution of test data at each test site normal? Is the defect rate beyond the reasonable range? In case of any abnormality on the, the system will alarm immediately and relevant personnel can handle it in time

4. Statistical analysis: conduct statistical analysis on the test data, find out whether the data distribution is reasonable, and analyze the possible quality problems of the product from the data distribution

there are many methods of data acquisition. It mainly includes: barcode scanning, manual data input, real-time communication with equipment to obtain data, etc

barcode scanning equipment includes automatic and handheld. Automatic scanning equipment is usually installed at the head and end of the production line. When the product flows through the line, it automatically scans the barcode pasted on the product. Handheld scanners are manually operated and often used in test sites. For example, when it is necessary to record whether the test results are successful, you can scan the barcode on the product first, and then scan the result code (errorcode). There can be multiple errorcode codes, such as success, errora, errorb, etc. through the statistics of various errorcodes, you can know the main causes of defects. In addition, if you need specific test data rather than just the results of success or failure, you can scan the product code first and then use the keypad to input data

it adopts scanning and keyboard input mode, which is relatively simple to implement. If you need more accurate data, such as furnace temperature data, you can use the way of communication with the equipment to collect the test results provided by the equipment in real time, but this way requires the equipment to have its own communication function. If the equipment does not support it, some test data can also be measured by installing detectors. For example, the furnace temperature mentioned above can be measured by using temperature detectors. The pressure and liquid level in the container can also be tested by installing detectors. However, these data acquisition require additional implementation costs

mes system not only collects data, but also analyzes and processes the collected data. In enterprises that have implemented MES, the person in charge of each post, the manager of the enterprise, and the customer can know the status of the production site at any time. Through the analysis of the recorded production data, enterprises can find the problem points in the manufacturing process and continue to improve. In recent years, the demand for MES system is increasing. On the one hand, enterprises need to improve their own processes. On the other hand, many enterprises in China receive orders for entrusted processing for customers, and foreign customers require enterprises to provide manufacturing process data. It is believed that in the next few years, MES will become a hot spot of manufacturing information system

the difficulty of MES system lies in data processing technology. When the enterprise is large, the reaction speed is the key. At present, there are relatively mature MES products abroad, such as factor of UGS company in the United States

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