| As an exceptional gear,non-circular gear not only has the advantages of good dynamic performance,high transmission ratio accuracy,reliable operation,high-speed transmission,and can realize the transmission between any two axes in space,but also can change the center distance transmission like the traditional cam and linkage mechanism,transmit the periodic non-uniform transmission ratio,and realize the required motion function output.It has been widely used in ve hicles,mechanical presses,textile machinery,hydraulic engines,pumps,flowmeters,clocks,and automatic toys.However,the complex shape of the non-circular gear pitch curve makes it difficult to manufacture.With the gradual improvement of non-circular gear design and the expansion of application fields,the manufacturing problem has become a short-plate problem that limits its promotion.Wire electrical discharge machining(WEDM)can process almost all types of non-circular gears and has the advantages of strong adaptability,low cost,and high processing efficiency.In this topic,in order to improve the surface integrity of non-circular gears,Pascal gears are taken as the research object to carry out the research on parameter optimization and surface integrity prediction under the wire electrical discharge machining process,aiming at the disadvantages of traditional machining methods for non-circular gears,low degree of machining intelligence and poor consistency of machining quality.The specific work is as follows:Firstly,by analyzing the basic principle of WEDM and combining the machining characteristics of non-circular gears,the WEDM machining characteristics of non-circular gears are explored.At the same time,combined with the performance of the machine tool,the tooth profile design of the non-circular gear and the determination of the test method and the test factor level are carried out.The comparative analysis shows that,regarding machining accuracy,WEDM has unique advantages for ma chining non-circular gears.Secondly,aiming at the problem that the current surface integrity evaluation system for cutting is not suitable for WEDM machining,a surface integrity evaluation system for WEDM machining of non-circular gears is constructed based on the analytic hierarchy process(AHP).The consistency test show s that the constructed evaluation system meets the requirements.Select the three evaluation indicators with the most significant impact on surface integrity to measure and obtain exper imental data.Thirdly,the orthogonal test method combined with the fuzzy comprehensive evaluation method(FCE)is used to optimize the parameters of the non-circular gear wire electrical discharge machining process,and the optimal combination of process parameters that meet the requirements of multiple surface integrity indicators is obtained.In order to prove the effectiveness of the FCE,it is compared with the grey correlation analysis method,which has been widely used.The results show that the optimization results obtained by FCE and grey correlation analysis method are consistent,and the optimization results are 19.37%higher than those before optimization,which verifies the effectiveness of FCE.Finally,the surface integrity prediction model is established based on the hybrid particle swarm optimization algorithm(HPSO)to optimize the support vector regression(SVR),and the effects of Poly,RBF,Sigmoid,and other kernel functions on the performance of the prediction model are compared and ver ified.The results show that the RBF kernel function’s prediction model has the best effect.Surface roughness R~2=0.9978,MAPE=0.4534,surface residual stress R~2=0.9483,MAPE=3.1673,surface microhardness R~2=0.9786,MAPE=0.4779.At the same tim e,based on the optimization and prediction model of surface integrity,a surface quality prediction system for non-circular gear WEDM is designed and developed. |
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