| Being as one of the core technologies of laser remanufacturing,the laser cladding technology has gradually been applied in the fields of aerospace,automobile manufacturing and petrochemical industry.However,many problems associated with the technology include the instability of the process,the surface's even quality of the cladding layer,and the need to improve accuracy of formed parts by machining them.In metal cutting,the hole drilling process accounts for about 40% to 50% of the total cutting machining.The small diameter twist drill is the main tool for small hole drilling.Therefore,the study is written for improving the small diameter hole drilling process of 304 stainless steel laser cladding.Based on research of drilling simulation and drilling test,the essay focuses on the drilling parameters of small diameter twist drills for drilling performance of 304 stainless steel cladding parts.Firstly,based on the new tapered surface grinding method and mathematical model analysis of the twist drill,the rake face is established according to the actual drill blade milling cutter contour curve.The flank is established by a natural intersection of two sides to establish a three-dimensional model of non-standard small-diameter twist drill.At the same time,the geometrical angle of the drill tip is measured.Combined with DEFORM-3D software,the essay aims to analyze key technologies in the drilling simulation process and establish drilling simulation model of 304 stainless steel cladding.Then,using a combination of single factor and orthogonal tests,the drilling force,drilling temperature and tool wear functioned as drilling performance indicators contribute to analyzing the influence of the diameter of the drill,the spindle speed and the feed speed of the small-diameter twist drill on the drilling performance of 304 cladding parts.According to the analysis of range and variance,the order and significance of each factor's influence on the performance index are determined,obtain the optimal drilling parameter combination and verify he simulation.Then,304 stainless steel laser cladding members are prepared by side shaft and coaxial powder feeding,respectively.The conduct of comparing the surface macroscopic morphology,cross-sectional microstructure and microhardness of the two-clad specimens and analyzing whether there are any structural defects such as pores,cracks and inclusions is to ensure the reasonable preparation of 304 cladding parts.According to the drilling simulation test plan and the drilling optimization parameters,the aim of drilling 304 cladding and the same element 304 stainless steel plate is to compare similarities and differences between the simulation and the experimental data and analyzed so as to verify the validity and accuracy of the simulated drilling model.This experiment also reflect the variation between the drilling parameters and the drilling performance indicators of the small diameter twist drill.Finally,the drilling force prediction model is established based on the orthogonal experimental data of 304 stainless steel laser cladding,the use of MATLAB software and the analysis of multiple regression.Then based on the multi-objective genetic algorithm,the multi-objective optimization of drilling parameters is carried out with the minimum drilling axial force and the maximum material removal rate as the objective function.The test results are verified by experiments. |
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