Edge Mechanical Passivation Technology For Natural Diamond Cutting Tools

Natural single crystal diamond has high hardness,anti-wear,great elastic modulus,and good anti-adhesion,along with a small coefficient of friction with non-ferrous metals and other materials.It is an ideal material for making ultra-precision cutting tools.At present,natural diamond tools have been widely used in the field of precision and ultra-precision machining,and have played an important role in the automotive industry,defense industry,microelectronics industry and other fields.Therefore,how to manufacture a natural diamond tool with high precision,long service life and good cutting quality has been a subject of great concern to scholars.At present,mechanical grinding is still the most important method of manufacturing natural diamond cutting tools.However,although the edge of the sharpened cutting tool is extremely sharp,nano-level notches and cracks occur together,which weakens the impact resistance of the tool and reduces the cutting edge.The mouth strength,in the turning process,is easily diffused into large cracks due to the vibration of the machine tool,which accelerates tool wear and even causes chipping,resulting in tool failure.Therefore,the removal of micro-defects on the cutting edge,passivation of the radius of the cutting edge to improve the surface quality and service life of the cutting edge is an important step in the preparation of an ideal natural diamond tool.This subject will add a follow-up treatment to the natural diamond tool after mechanical grinding,to increase the service life of the tool,that is,use a high polymer polishing pad on a high-precision grinding machine,and apply a layer of nanometer on it.Hard abrasive grinding paste,the passivation of the tool to achieve the purpose of improving the efficiency of the passivation without reducing the surface quality of the cutting edge.In order to achieve this goal,the paper first analyzes the wear conditions in the cutting process of similar diamond tools,and analyzes the possible influencing factors in the process of passivation of natural diamond tools,and designs the process of passivating the cutting edges of tools.A complete tool edge passivation process system was established and the four key process parameters were determined.The spindle speed w,the abrasive mass fraction of the abrasive paste y,the reciprocating frequency of the grinding disk p,and the tool swing speed q;simultaneously the creativity The six indicators for evaluating the blade passivation process are proposed.They are the obtuse circle radius R after passivation,the arithmetic mean deviation Ra and the profile maximum height Ry,and the surface quality improvement index l after passivation.Material removal efficiency index e,micro defect evaluation index f.Then,this system uses this system to carry out feasibility verification experiments.From the experimental results,it can be seen that the mechanical grinding of natural diamond tools using the combination of grinding paste and polishing pad can really play a good passivation effect;and based on control variables.A number of experiments were performed to determine the most suitable process conditions for the passivation of Si O2 abrasives with an abrasive grain size of 30 nm,and 530N7501 polishing pads without grooves;this article is based on Raman spectroscopy after passivation and passivation.The experimental phenomenon shows that the material removal mechanism during passivation process: the high-speed smooth rotation of the spindle and the good vibration damping of the soft polishing pad provide a high-temperature stable reaction environment for the passivation process of the tool,the edge and the abrasive paste,and the polishing pad When the high-molecular polymer is in full contact,the surface layer carbon atom has higher energy,and then the functional group and the polymer are adsorbed and detached from the cutting edge during the rubbing process;at the same time,the surface carbon atom will produce a continuous amorphization process because the hardness becomes low.It can be removed by the micro-cutting action of abrasive grain.Finally,this article clarifies all the process parameters affecting the passivation quality and passivation efficiency throughout the passivation process.The passivation experiment is used to obtain training data,and a three-layer radial basis function passivation process is established based on the Matlab neural network toolbox.The parameter model can obtain the obtuse circle radius R after passivation,the average surface deviation Ra after passivation,the surface quality improvement index l and the material removal efficiency index e.A total of four indicators of passivation quality and passivation efficiency were evaluated.Finally,based on this model for optimal solution,the optimal passivation quality process parameter combination is t=19min,w=1800rpm,y=60%,p=0.312 Hz,q=9°/s,At this time,the surface quality of the passivated cutting edge is optimal,Ra_min = 0.6422 nm;the combination of the process parameters with the highest passivation efficiency is t=22 min,w=3600 rpm,y=55%,p=0.245 Hz,q= 15°/s,the material removal rate during the passivation process is maximum,e_max = 156.7141 nm²/min.