Research On Key Technology Of Laser Brazing CBN Abrasive Tool

Brazed super abrasive tools have remarkable advantages, such as high grit exposure, large storage space, strong grit retention, high grinding efficiency and high utilization rate of grits which have become a current hotspot problem in the research field of super abrasive tools. Presently, there are three preparation methods for brazing super abrasive tool:vacuum furnace brazing, induction brazing and laser brazing. The different preparation methods have their unique advantages and working field. Additionally, they also have some inevitably disadvantageous. Laser brazing not only can satisfy the requirement of the brazed temperature, but also can realize orderly arrangement of abrasives according to integrating CAD technology.This paper refers the theory of Laser Cladding and Laser Rapid Prototyping Technique, and deeply analyzed characteristics and interaction principles of laser, solder and CBN abrasives. Using YAG laser as a heat source, the paper carried out the experiment of high-temperature brazing 400 mesh level CBN grits, and made some attempts to optimize the laser brazing process parameters in order to Preparation of good grinding performance of super abrasive tools.The main contents in this paper are as follows:(1) This paper investigated the forming mechanism of laser processing technology, the physical and chemical properties of CBN and the solderability of CBN, the basic requirements of solder and interface reactions of CBN and solder. The formation mechanisms of molten pool in the section of brazing specimen and the factors of main influence on the surface quality of brazing specimen have been analyzed. Meanwhile, the corresponding measures to improve the surface quality were proposed.(2) A gaseous protector was designed and produced, which not only can cooperate with the working of laser and workbench, but also can provide Argon gas protection atmosphere. It also carries selective scanning brazing CBN with high transmittance and low energy loss.(3) Adopting Cu and Ti powder as solder, brazing process scheme and pretreatment process were designed. Many groups of experimental for different parameters were carried. At the same time, Infrared Thermal Imager was used to measure temperature during laser brazing process and the law of temperature change was concluded.(4) According to the results of Ultra-depth Microscope, the paper analyzed that parameters such as current, scanning speed and defocusing amount have different influence on the quality of the surface of brazing specimen, and researched the forming reason and improvement measures of defects, such as burr, spheroidization, stomata, and crack. The behavior of element diffusion observed and analyzed by Scanning Electron Microscope (SEM). Phase components of brazing specimen were provided by X-ray diffraction (XRD)...