| As one of the modern cutting processes,broaching is widely used in various complex and precise parts processing due to its high efficiency,high precision and easy operation.With the increase of the number of broaching,the degree of tooth wear is gradually increased,and the maximum peak value in the broaching time domain load curve can reach more than 10KN,which seriously affects the broaching performance.Therefore,how to accurately and accurately describe the broaching load change characteristics after the cutter teeth wear has great practical significance for optimizing the relevant process parameters in the broaching process and improving the processing quality of the workpiece.In this paper,the influence of the tooth wear on the time-domain load characteristics of the inner hole broaching process is studied.With the LG612Ya-800 horizontal broaching machine as the test platform,a model of internal hole broaching load considering the flank wear of the tooth was proposed.Ideas.Starting from the classical cutting modeling theory,the total broaching force was decomposed into the absolute sharp state of the tooth(no flank wear).The cutting force and the flank face of the tooth are affected by the internal hole effect of the workpiece and the chip groove.After the friction generated by the contact with the surface of the workpiece at the wear point,a model of the internal hole broaching single tooth load considering the wear of the flank of the cutter was established.Based on the alternating periodic variation of the number of simultaneous cutting teeth over time,a multi-tooth time-domain load model was established based on the single-tooth load model.The main research work of the thesis is as follows:(1)Overall design of the internal hole broaching test system.According to the data signal sampling requirements of the tooth wear test,the hardware and software parts of the test system were analyzed and designed,including the analysis of the important components and working principle of the broaching machine,and the mechanical structure installation and test platform of the sampling device.The electrical circuit and component selection were designed,and finally the matching of the channel parameters of the sampling software interface was optimized.(2)Establish a bore broaching load model that takes into account the flank wear.Based on the classical cutting modeling theory,the total broaching force was decomposed into the absolute sharp state of the cutter(no flank wear).The cutting force affected by the internal hole effect of the workpiece and the chip groove and the flank of the cutter were worn.A frictional force generated by contact with the surface of the workpiece at the wear point establishes a single tooth load model.A multi-tooth time-domain load model was established based on the alternating periodic variation of the number of simultaneous cutting teeth over time.(3)Research on tooth wear test.The internal hole broaching test system platform was built according to the hardware and software design requirements.The cutter tooth wear test program was designed to collect the three data signals of load,displacement and oil pressure in real time on-line with the sampling frequency of 1028 Hz,the number of times the flank wear of the cutter teeth and the blunt circle radius of the tool tip were taken offline.Analyze the change law of the tooth wear of each part and the change trend of the time-domain waveform curve of the broaching load.(4)Model numerical simulation and comparative analysis.The multi-tooth time-domain broaching load model established by MATLAB was calculated to obtain the theoretical broaching load time domain waveform curve.The theoretical load time domain waveform curve and the measured load time domain waveform curve under the same number of broaching times were compared.The influence of the flank face wear on the internal hole broaching load was discussed.And further analyze the errors and causes in the theoretical model. |
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