# Research and Progress on Truing and Sharpening Process of Diamond Abrasive Grinding Tools
## 3 Dressing Method of Diamond Abrasive Grinding Tools
### Sharpening Technology of Diamond Abrasive Grinding Tools
#### 3.2.4 Laser Sharpening Method  
Figure 14 shows a schematic diagram of the laser sharpening diamond abrasive grinding tool. Its working principle is that the laser beam, with a certain power density, is directly irradiated on the diamond abrasive grinding tool as a \"processing tool\", and the surface temperature of the grinding tool rises rapidly. Using the difference between the melting point of the bond material and the diamond abrasive grains, the bond material is heated, melted, and gasified, then separated from the diamond abrasive grinding wheel in a gaseous or plasma state to achieve the purpose of sharpening. At the end of the 20 th century, [PERSON] [45] of the University of Brunswick in Germany, first proposed the application of laser technology to the dressing of superhard abrasive grinding tools. [PERSON] et al. [46] carried out laser ablation experiments on resin-bonded diamond abrasive grinding wheels based on the nanosecond laser dressing process parameters to realize low-damage and ultra-precision dressing of the resin-bonded diamond abrasive grinding wheels and proposed a new laser dressing method based on layered scanning to solve the problem of the degradation of abrasive performance caused by ablation heat. [PERSON] [47] irradiated the pulsed laser on the surface of diamond abrasive grinding tools, which could obtain ideal abrasive grain protrusion height and cutting of the abrasive grain binding force. Our team [48; 49; 50] studied the theory and numerical modeling of plasma isothermal expansion produced by nanosecond laser ablation of bronze-bonded diamond abrasive grinding wheels and deduced the dynamic equation of plasma expansion, which could provide a reference for future research on plasma characteristics. A new method of dressing bronze-bonded diamond abrasive grinding wheels with water-column-flow-assisted pulsed fiber laser was proposed. The ideal dressing effect was obtained through the dressing test, as shown in Figure 15, which was of significance for optimization of the dressing process. Figure 13: The surface condition of the grinding wheel after electric machining [44]. Through the above-mentioned domestic and foreign research, it was found that the diamond abrasive grains, after laser sharpening, protruded by one-third of the height of the bond, there was chip holding space around the abrasive grains, and the dressing efficiency was approximately 80\(\sim\)88%. Numerical Simulation and Experimental Research on Laser Dressing Bronze Diamond Abrasive Grinding Wheels  
Dressing diamond abrasive grinding tools is mainly divided into two steps: truing and sharpening. Among the truing methods, the laser truing method has the highest efficiency--approximately 70\(\sim\)80%. Similarly, the dressing efficiency of the laser sharpening method ranks first among all sharpening methods at approximately 80\(\sim\)88%. Laser  
Figure 14: Schematic diagram of laser dressing diamond abrasive grinding wheel. Figure 15: Topography and landform of bronze diamond abrasive grinding wheel after multi-pulse fiber laser dressing. processing is a comprehensive, efficient, and green dressing method. Therefore, numerical simulation analysis and related experimental research have been carried out for the method of laser dressing of diamond abrasive grinding tools. When a pulsed fiber laser is vertically incident on the surface of a bronze-bonded diamond abrasive grinding wheel, a variety of complex physical phenomena are involved, such as serial energy superposition and the accumulation effect. Different from the continuous laser, the working mode of the pulsed laser is to produce a laser output at a certain interval. After the end of the previous pulse, except for a small part of the heat transferred to the air, most of the heat is deposited in the bronze-bonded diamond abrasive grinding wheel and provides energy for the next laser pulse to reach the surface of the grinding wheel.