Research On The Precision Dressing And Grinding Technologies Of Super-Hard Abrasive Tools With Sophisticated Shapes

Super-hard abrasive which has high hardness,wear resistance and excellent grinding capability,has more and more used in grinding filed.It is the highest precision and sophisticate tool in super-hard abrasive tools and is used to machining precision parts with sophisticated shapes.Sophisticated shapes refer to the part's shaft section formed by the combination of straight line,oblique line and circular arc.The super-hard abrasive tool with sophisticated shapes is a tool which is made of super-hard abrasive with complex working surface and apply to grinding.The shape precision is one of the main factors affecting the machining accuracy.For example,the profile of the turbine blade tenon grooves in the aeroengine is about 5?m,and the tenon grooves are not only the non-circular surfaces,but also the pitch of the tenon teeth is about ±2.5?m.High precision super-hard abrasive tool with sophisticated shapes is usually made by shaping and dressing.The precision dressing technology for sophisticated shapes is one of the key factors.Therefore,timely researching on it plays an important role in improving the manufacturing level of precision tools and promoting the development of its application fields.Aiming at the dressing and grinding technology of the super-hard abrasive tool with sophisticated shapes,this paper has carried out a scientific and systematic research on the mechanism,method,basic process rules and application of precision dressing and grinding by the theoretical analysis and experimental.Established the technology that dress and grind super-hard abrasive tool with sophisticated shapes by grinding method and achieved high efficiency and accuracy of dressing.The specific research contents are as follows:1.Study on the mechanism of precision dressing and grinding.Based on the physical and chemical properties of diamond and crystal structure,analyzed the phenomenon of diamond form cleavage and cleavage's modification of existing dressing methods.According to the different methods' working principles,dressing efficiency and accuracy,this paper selects the precision dressing and grinding method based on grinding.Analyzing the dressing and grinding process,the way of diamond grinding is mainly wear and a small amount of grains micro-breakage,which is verified by microscopic observation.And the grinding energy formula is optimized to provide theoretical basis for the follow test.2.Precision dressing and grinding method of sophisticated shapes.Finish dressing and grinding shape units such as parallel cylindrical,conical bevel and combination by using modified optical-guide curve grinding machine.Through the method of indirect measurement,measure the dressed shapes by the image measuring instrument and the three coordinate measuring instrument and the accuracy can reach micron level.Summarized a complete series of precision dressing and grinding method.3.Basic process rules of precision dressing and grinding.Through the study of mechanism,the main influence of dressing and grinding efficiency is obtained.The technological factors are diamond grinding wheels' grains size,binder and depth,speed of grinding.Each of the four factors were designed experiments,basic rules are as follows: Diamond grinding wheels' grains size should be selected by the grinded tools and the size should not be too large or small.The vitrified bond diamond grinding wheels' performance is the best and efficiency is the highest.The deeper the grinding depth is,the higher the efficiency is.However,in order to maintain accuracy,the depth should choose the right value according to the grinding allowance.As the grinding speed increases,the grinding efficiency increases first and then decreases.4.The application of precision dressing and grinding technology.Carried out a grinding test on the single raceway bearing grinding diamond roller,test results show that the radius of precision can reach ±4?m,roundness is 4?m,step angle is ± 5?.Carried out a grinding test on the multi raceways bearing grinding diamond roller,test results show that the raceways' spacing can reach ±3?m,curvature is 0.002.The tests show that the overall accuracy of precision dressing and grinding technology based on the grinding method,can reach 5?m and the accuracy of single element can reach 3?m.The tests prove that it can be applied to actual production.