| The driving force of the manufacturing industry comes from the continuous demand for practical applications.At present,all kinds of equipment and facilities are developing intelligently,integrated and modularized,in this trend of development,the demand for micro structural parts is increasing.There are many small features in micro parts,such as micro chamfering,miniature slots and tiny holes,and there are similar small features in many conventional parts.Micropores are widely used in the parts of electronic and medical equipment,and play a crucial role.High efficiency and high quality processing technology for micropores has aroused great concern in the related fields.Aluminum based silicon carbide composite(SiCp/Al)is a particle reinforced metal matrix composite reinforced with silicon carbide(SiC)particles and metal aluminum as the base material.This material has the advantages of high specific strength and specific stiffness,good dimensional stability and so on.Compared with the high cost of continuous fiber composites,the low cost and high performance of SiCp/Al composites has been widely applied in aerospace,military and medical devices,and many of the parts contain microporous features.Therefore,the research on micro hole processing technology of this kind of material has high practical value.Mechanical drilling is a processing method with high efficiency and high stability.It has high application value.There are few reports on the research of microporous drilling of SiCp/Al composites at present,both in theory and in experiments.In this paper,a series of finite element simulation and Experimental Research on the mechanism of micro-porous drilling of Si Cp/Al composites are carried out.The deformation of material and the appearance of drilling chip are discussed,and the key analysis of drilling force(axial force and torque)is carried out by combining the structural characteristics of the material.By comparing the results of analytical calculation,simulation and test data,a more accurate method of prediction and accuracy evaluation of drilling force is summed up.The main contents are summarized as follows:1.The simulation research on the cutting of SiCp/Al composite based on ABAQUS/Explicit is carried out.(1)A two-dimensional orthogonal micromachining simulation model is established by considering the SiC reinforced particles and the Al matrix respectively.The deformation of material(Including the destruction of the Si C particles and the enhanced interface and the deformation of the Al matrix,etc.),distribution of stress field and the changing law of cutting force are studied in the cutting process;(2)Finite element simulation of microporous drilling process with diameter of 0.5mm is simulated.The process of drilling and the mechanism of deformation are studied in depth.By comparing with the experimental data,the influence of key simulation parameters on the calculation results of drilling force is obtained,and the improvement strategy of calculation precision is put forward.Finally focus on the variation of drilling force under the different drilling parameters.2.Based on the analysis of the force of the micro-drill and the simulation of the oblique cutting,the prediction model of the microporous drilling force of the SiCp/Al composite is obtained.3.The 0.5mm microporous drilling test for Si Cp/Al composites is carried out,and the experimental conclusions about drilling force and drilling quality are obtained.(1)Under different spindle speed and feed speed,the change law of axial force and torque is analyzed,and the influence rules of various factors on drilling force are explored;(2)The orthogonal test of drilling is carried out by the way of pecking drill,and the influence degree of the influence factors on the drilling force and the optimum combination of parameters is obtained;(3)Combined with the result of the test data,the empirical formula of drilling force is obtained by statistical method,and the influence of each factor on the drilling force can be explained from the mathematical point of view.(4)The accuracy evaluation of drilling force results is obtained by comparing the results of theoretical calculation,simulation and test.(5)The effects of different processing methods on the chip morphology,machining quality and bit wear are summarized. |
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