Study On The Lapping Technology Of Diamond Slicing Knives

Ultrathin sectioning technology is widely used in biotechnology, pathologic diagnosis, nanotechnology, etc. In order to observe the micro-structure of sections under transmission electron microscope clearly so that some useful physical information can be obtained, the specimen must be cut into ultrathin slice with an average thickness of 30-70 nm.This require that the diamond slicing knife must be very sharp so that serial ultra-thin sectioning can be implemented, and the edge cannot exist large micro defects, or the section will be destroyed and appear cutting artefacts which are in particular knife marks, compression, crevasses. Therefore it is very crucial to study the mechanical lapping technology of the diamond slicing knife to improve its quality and realize the manufacturing technology independent innovation.First, according to the requirements of the diamond slicing knife sharpening process, writing a software controlling the movement of the linear guide based on RS232 serial port communication, the Modbus communication protocol and servo motor parameters control. Based on the optical microscope detection and acoustic emission on-line monitoring, observing the changes of the rake face, flank face and the edge, analyzing the change law of acoustic emission signal energy, then identifying different polishing process of the diamond slicing knife.Second, determining the cutting edge radius, micro defects along the whole blade length,cutting edge roughness Ra and Rz as four evaluation index for the quality of the diamond slicing knife, and using optical microscope and atomic force microscopy to measure the edge of the diamond slicing knife. Through the polishing process test, analyzing the influence on the quality of diamond knife of gas supply pressure of the spindle, accuracy of dynamic balance, polishing angle, feed, diamond particles type, polishing fluid, ultrasonic vibration and vacuum heat treatment, then established the mechanical polishing technology of the diamond slicing knife primarily.Thirdly, based on the optimized process parameters obtained from the experiments, manufacturing two diamond knives. The quality can be achieved: cutting edge sharpness is 24.78 nm, edge roughness Ra is less than 3nm,and Rz is less than 15 nm. Then a sectioning test was carried out using the diamond knivesFinally, analyzing the cause of the knife marks, compression, crevasses on the surface of the sections, studying the impact of the wedge angle, relief angle, section thickness and cutting speed on the quality the sections and verified the diamond knives’ cutting performance by sectioning test, the diamond knives have superior performance cutting the thick sections, and can achieve 30 nm serial section, the 50 nm thick section has only a small amount of knives marks or crevasses, and the diamond knives has meet the demand of the ultrathin sectioning basically.