Products are the lifeblood of a company, quality is the life of a product, and reliability is the soul of quality. With the development of science and technology, products are increasingly diversified. The structure of products varies greatly, and the mode of failure is also varied. Among the many factors that affect reliability, the determination of key factors is an important task of reliability analysis. EDM technology is a very important modern processing method. With the development of new materials and new processes, the application of WEDM has become more and more popular. Its good flexibility and stable processing precision have brought huge benefits to users. However, the high failure rate of the wire electric discharge machine (especially the high-speed wire-cut wire-cut electric discharge machine) caused the downtime and maintenance costs to bring great inconvenience and waste of resources to users. Therefore, the problem of improving the reliability of the wire cutting machine is eagerly placed before the machine tool manufacturers and users. Nickel Fluoride 2836999000,45 Alkaline Nickel Carbonate,Nickel Fluoride 98,Fine Chemicals Nickel Shaoxing Yingke Metal Extracting Co., Ltd , https://www.nickelsalt.com
For the reliability study of the wire cutting machine, a large amount of accurate data is needed. Since the wire cutting machine is an integrated system with high automation and complex structure using machinery, electronics, computers, and electrical processing technologies, the acquisition of reliability data requires not only a large amount of manpower, material resources, and a long time, but also the input of samples. The cost of the experiment is high. At present, the reliability data of wire cutting machines collected in actual use in China is almost blank. This paper aims to select a wire-cut electric discharge machine with a typical structure, track and record the fault data of 20 high-speed wire cutting machines used throughout the country, and obtains more accurate and reliable reliability data. The characteristics of the cutting machine itself and the actual conditions in use, the line cutting machine is divided into 15 subsystems, and 43 types of failure modes and 36 types of failures are identified. The reliability database of the line cutting machine is established based on Power2Builder and Sybase. The reliability analysis and reliability design of the cutting machine provide the basis.
The statistics and analysis of fault modes and fault causes of the 2-wire cutting machine are based on the reliability database of the wire cutting machine, and the fault location (subsystem), fault modes and fault causes are analyzed. The subsystems where the fault of the wire cutting machine occurs more often are wire feeders (59.322%) and electrical systems (28.814%). The failures of these two subsystems accounted for 88.136% of the total machine tool failures, of which the wire feeder device was the most frequent failure, and its failure frequency was much higher than other parts. The wire feeding device includes parts related to wire transport, such as a wire feeding motor, a screw and a nut, a synchronous toothed belt, a coupling, and an electric feeding block. The wire feeding device is the most important factor affecting the reliability of the wire cutting machine, and improving its reliability level is a top priority. The more frequently occurring modes of high-speed wire cutting machines are component damage (25.424%), low machining efficiency (20.339%), and component damage (15.254%), and the most common causes of line-cutting machine breakdown are components. Damage (28.814%), wear (22.034%), and damaged parts (18.644%). Damage to parts and components and damage to components mainly refer to the damage of synchronous toothed belts and electrical and electronic components, and these components are mainly obtained from outsourcing, indicating that the quality of outsourcing and outsourcing components is poor and measures should be taken. Improve it. In addition, the failure frequency of the thread cutting device of the wire cutting machine obviously exceeds other parts, indicating that the wire feeding device needs to be greatly improved to improve the reliability level of the machine tool.
3 Subsystem failure analysis The wire feeder is the most frequent part of the failure and is the most important factor affecting the reliability of the wire cutter. The failure mode of the wire feeding device is mainly low processing efficiency and component damage, accounting for 57.143%. The main reason for failure of the wire feeder is wear, component damage and breakage, accounting for about 80%. Due to the use of a single-feed block in the structure, the two-way transport wire causes good and bad contact between the single-entry block and the electrode wire, and often causes a series resistance phenomenon, thereby reducing the service life of the feed block. It also reduces processing efficiency. Zero, component damage is mainly synchronous tooth belt failure. The electrical system is the site where the failure occurs more frequently and is the main factor affecting the reliability of the wire cutter. The failure mode of the electrical system is mainly the damage of components, which is as high as 82.353%. The main reason for the failure of the electrical system was component damage, accounting for 76.471%. Electrical and electronic devices are mainly obtained from outsourcing, which indicates that the quality of outsourcing and outsourcing components is poor.