| In response to the development plan of "Chinese Manufacturing 2025",the Chinese machining industry objectively is required to improve mechanical processing accuracy.An important evaluation index of processing accuracy is the machined surface roughness of the machined part,the machined surface roughness is the result of the joint action of many factors in the machining process,existing relevant research results had shown that on the condition that the combination of cutting tools and work-pieces was determined,the cutting parameters would have significant influence on the machined surface roughness,on the other hand,the cutting parameters of feed per tooth and cutting depth were nearly in positive proportion to the cutting force,which indicates that the cutting force might be related to the machined surface roughness.Although domestic and foreign scholars had done much research on cutting force and machined surface roughness,but had not been clear about the mechanism of cutting force influencing machined surface roughness,and the precise relational model of cutting parameters with machined surface roughness had not been established.Therefore,this research aimed to establish a rather precise mathematical relational expression between cutting parameters and machined surface roughness,and clarify the significance of the relationship between cutting force and machined surface roughness,thus to better guide the design of cutting parameters in actual machining production,and to provide basis for the research of the mechanism that cutting force influencing machined surface roughness.Main researching contents were as follows:(1)The existing micro-element instantaneous milling force model and the surface roughness theory were analyzed,it was found that the common factors influencing the milling force and the surface roughness should mainly be cutting tools and cutting parameters,among which the feed per tooth should have particularly significant influence.(2)Work-pieces with three materials of #45 steel,AISI 304 stainless steel,and 7475 aluminum alloy,and carbide milling cutters with different diameters and different numbers of tooth were used,and methods of single factor test,orthogonal test and response surface test were applied to carry out cutting experiments,the cutting force and the machined surface roughness in each test were measured,and the experimental data of the cutting force and the surface roughness corresponding to cutting parameters,and parameters of cutter were obtained.With these experimental data,the relationship curves of the machined surface roughness and the cutting force with cutting parameters and parameters of cutter for these three materials were drawn,and the results indicate that cutting parameters and cutting tool parameters should have significant positive correlation with the machined surface roughness and the cutting force,the combination of feed per tooth and axial depth of cut should have great influence on the machined surface roughness.(3)The quadratic polynomial prediction models of component milling force and surface roughness were established based on the data obtained from response surface tests,and the prediction accuracy of these model were verified by other experiments,the results showed that the accuracy of the prediction models of milling force and surface roughness reached over 90% and 83%,which indicates that the established polynomial prediction models should be relatively accurate.(4)Applying the data obtained from the single factor test,the data fitting of milling component force and machined surface roughness was done by use of the connection function in the statistical software of SPSS22.The fitting coefficient was near to 1,which indicates that there should be rather strong correlation between the milling component force and the machined surface roughness.Besides,the correlation coefficient of Pearson Product Moment was used to carry out double-tail inspection on the correlation between the machined surface roughness and the milling force,and the result showed that the average correlation between the machined surface roughness and component milling force reached over 0.89.These results indicate that the correlation between the machined surface roughness and the milling component force should be very high,which is consistent with the results of theoretical analysis.This research makes the degree of correlation between surface roughness and milling force clear,no matter which factor as feed per tooth,axial depth of cut and spindle speed changes,there would always be significant linear relationship between surface roughness and milling force. |
