Preparation Of Diamond Abrasive Grain With Positive Rake Angle By Femtosecond Laser And The Research Of Its Grinding Experiment

Diamond,as a kind of super hard material with high hardness,high strength,excellent thermal conductivity,and wear resistance,is extensive used in the production of processing tools and grinding tools.However,due to the high hardness,high strength and other characteristics of diamond,it is easy to have problems such as low machining efficiency,low manufacturing quality and long machining duration in traditional grinding process;when using long pulse laser for processing,there are adverse effects such as energy accumulation thermal damage,which largely limit extensive usage of diamond cutters and grinding tools and the development of related technologies.Because femtosecond laser has the characteristics of extremely short pulse width and high single pulse energy.During machining,it has no direct contact with the material to be processed.Therefore,it can overcome the problems of long processing time and seriously tool wear in traditional grinding,in addition,there will be no problems such as energy accumulation like long pulse laser machining.It has obvious advantages in the micro-machining of diamond and other materials.Generally,the rake angle of diamond grinding tool was negative rake angle,which is easy to cause large grinding force during grinding and affect the surface quality after grinding.In view of the above problems,an experimental platform for femtosecond laser machining of single crystal diamond was built in this thesis.An abrasive grain with positive rake structure was produced,besides the diamond grinding wheel was designed and manufactured.Grinding experiment of diamond abrasive grain with positive rake angle and negative rake angle was carried out to verify the grinding performance of diamond abrasive grain with positive rake angle.The main contents are as follows:(1)The processing difficulties of diamond materials and the processing characteristics of femtosecond laser were introduced,and the research status of single abrasive grinding and femtosecond laser machining diamond at home and abroad were summarized.An experimental platform for single crystal diamond processing was built.(2)A simulation model of single abrasive grinding was established to simulate the single diamond abrasive grain grinding difficult-to-machine material Ti6Al4 V with positive rake angle and negative rake angle,respectively.The influence of different process parameters on grinding force and highest grinding temperature was analyzed.The simulation results showed that the grinding force is smaller and the highest grinding temperature is lower when grinding with positive rake angle.(3)In view of the previous research,the single diamond abrasive grain with positive rake structure was manufactured by using the best ablation parameters,and the diamond grinding wheel for grinding test was prepared.(4)Grinding experiment of difficult-to-machine material Ti6Al4 V was carried out by using diamond abrasive grain with positive rake angle and diamond abrasive grain with negative rake angle,respectively.The grinding force during the grinding process was measured,the surface morphology after grinding was observed,and the surface roughness after grinding was measured.It was verified that the grinding force can be significantly reduced and the surface quality of material after grinding can be improved by using the diamond abrasive grain with positive rake angle.