The Study Of The Development And Abrasion Mechanism Of The Diamond Cutter In Processing SiCp/Al Composites

As a new type of material owned numerous superior performances,SiCp/Al composites have been widely used in space flight and aviation,automobile,elect ronic engineering,optical instrument,sports equipment and other field.However,since SiCp/Al compositesare in high processing difficulty,especially high efficiency and precision processing on that with high volume fraction have become one of technical difficulties in the processing industry.Consequently,development on tools suitable for processing of this material turns into the key point to solve this problem.This paper will introduce characteristics of SiCp/Al composites,processing technology and machining effect of current tools.It developed two type of diamond cutters to process SiCp/Al composites with high volume fraction,which have realize high efficiency and precision machining of this composite material.Analyze abrasion types of diamond cutters and study its wear mechanism.1.Face milling cutter with the large particle monocrystal diamond in directional alignment has been developed,mainly used in face milling with large area and removal quantity for SiCp/Al composites in high volume fraction to realize high efficiency and precision machining.Carry out angle and mould designs on cutters in accordance with service condition and processing situation.Adopt powder metallurgy with cold press molding and hot pressing to obtain face milling cutter.The processing test has demonstrated that this milling cutter can realize removal quantity as much as 10 kilograms per day.It can achieve rough machining of face milling with large quantity of removal amount and finish machining with large plane and low roughness and obtain characteristics such high efficiency,long endurance and high durability.2.Develops CVD diamond end mill mainly used in form imitation and hole and milling processing.Incise and polish diamond,adopt powder metallurgy technology3 / 4with cold press molding and hot pressing to make diamond and metal powder alloy into hole milling cutter.Roughly grind main and auxiliary relief angles in accordance with service condition and processing situation and then grind accurately to acquire CVD diamond end mill.The processing test has shown that its tool life can reach as long as eighty hours and removal amount can reach over four kilograms per day.The processing hole is also in high precision and superior form imitation.Therefore,it can realize the high-precision form imitation processing of SiCp/Al composites and obtains characteristics such as high efficiency,long endurance and high durability.3.Analyze abrasion forms and propose improvement plan.It exists abrasion in rake face and flank surface of CVD diamond end mill as well as boundary wear.Its abrasion mechanisms are abrasive and adhesive wear.Targeting at this problem,simulation internal stress cloud distribution diagram when diamond is squeezed by single SiC particle by virtue of ABAQUS finite element analysis software and calculate durable length of CVD diamond end mill into 57.2km in accordance with stress nephogram and abrasion width of cutter.After simulating internal stress cloud distribution of diamond under the circumstance of cutting edge passivation,it is found that pressure intensity on tip of diamond after cutting edge inactivating is much less than that on the tip of right angle,which explain circular arc-shaped wear land emerged after tool wear as well as indicate that feasibility of reducing abrasion through passivation on cutting edge.4.It is normal for cutter to generate abrasion.When it reaches certain level,strong impact will make abnormal wear and tear happened.The wear figure has demonstrated that most cracks of CVD diamond end mill are located near the connections between cutter body of rake face and diamond.We consider that increasing temperature will soften solder part and cause falling of diamond.Based on this problem mentioned above,we build mould and propose that mix solder with certain volume fraction of aluminium oxide.It has been calculated that when percentage of mixed aluminium oxide reaches 2% and 5%,anti-pressure competence will become 1.5 and 1.9 times of original one respectively,which provide possibility for mixing aluminum oxide into solder in diamond welding to strengthen compressive strength and reduce abnormal abrasion of CVD diamond end mill.