Modeling Of Reciprocating Wedm And Optimization Of Wire Tension Control

With the rapid development of modern science and technology,various new materials of high melting point and high hardness have been emerging continuously,the studies of materials processing technology have been concerned by academia and industry.Due to its unique processing and erosion principle,EDM can avoid direct contact between the tool and the workpiece,so there is almost no cutting force,and it can rely on the instantaneous high temperature generated by the spark discharge to achieve the desired machining effect.The reciprocating WEDM is a self-developed EDM technology with Chinese characteristics.Compared with the one-way wire cutting widely used abroad,it has the advantages of low cost and high processing efficiency.However,the vibration of the wire during the wire cutting process seriously affects the processing quality,which restricts its further development.Designing a practical vibration control scheme can effectively solve this problem.In this paper,the general situation of reciprocating WEDM is introduced,and the research status of discharge state detection technology and vibration control is summarized.Then,the factors influencing the vibration of the wire during the wire cutting process are deeply analyzed,and the vibration equation of the wire is established.Based on the theoretical basis,several feasible schemes for suppressing the vibration of the wire are proposed.Through comprehensive analysis,the control is determined by the comprehensive analysis.The wire tension in turn suppresses the idea of wire vibration.Based on the idea of controlling the tension of the wire to suppress the vibration of the wire,a bilateral tension control device was designed,and the main components of the control device were designed in detail.The detection of the gap state uses the detection circuit based on STC89C52 single-chip microcomputer.According to the experimental conditions and processing needs,the AD conversion PCF8591 and the analog switch CD4051 are selected.In order to analyze the data after the gap state detection to obtain the feed amountrequired for the tight wire structure,a two-level fuzzy logic control system is designed.The first-level fuzzy inference identifies the real-time gap state,and the discharge state in the sampling period is counted to obtain the spark rate.The second-level fuzzy inference determines the feed amount of the tight-wire structure according to the spark rate in the sampling period,and the feed amount is fed.Information is transmitted to the controller,which controls the movement of the ball screw to achieve a tight wire.The membership function of the second-order fuzzy logic control system is optimized by BP neural network,which makes it more suitable for wire tension control of wire cutting.The intelligent tension control system was installed on the reciprocating wire cutting machine of the training center.The machining experiment was carried out using45# steel.The experiment was divided into two parts,one part was carried out on the machine tool with the tension control system closed,and the other part was opened.The tension control system was carried out on the machine tool as an experimental group;a total of 10 sets of test speeds were processed,and the surface roughness and dimensional error were measured after the end of the processing.The measurement results show that the surface roughness and dimensional error of the experimental group are reduced by 13.4% and 9.5%,respectively,compared with the control group.Therefore,the intelligent tension control system designed in this paper has a good effect on improving the processing quality of reciprocating wire cutting machine tools.