# Research and Progress on Truing and Sharpening Process of Diamond Abrasive Grinding Tools
## 3 Dressing Method of Diamond Abrasive Grinding Tools
### Truing Technology of Diamond Abrasive Grinding Tools
#### 3.1.4 Electric Discharge Machining (EDM) Truing Method  
EDM truing methods, including the electrolysis method and the electric spark method, are suitable for dressing a grinding wheel with a conductive material as a bond. Among them, the electrolytic method refers to the dissolution and etching of metal bonds through an electrolyte anode with the assistance of a formed cathode and mechanical friction. The electric spark method refers to the use of electric corrosion to remove the bond materials and diamond abrasive grains by use of a pulsed electric spark. [PERSON] et al. [18] carried out electrochemical machining dressing on a multi-layer brazed coarse-grained diamond abrasive grinding wheel containing a CMS electrolyte. This method could effectively improve the machining surface quality. CMSs could increase the electrolytic capacity of the electrolyte, enabling the wear abrasive particles to fall off smoothly, and reducing the occurrence of processing defects, such as grinding surface breakage and cracks of the diamond abrasive grinding wheel. [PERSON] et al. [19] proposed a novel active gap capacitance electric discharge machining (AGC-EDM) method for efficient machining of polycrystalline diamond. [PERSON] et al. [20] discussed the electrochemical dressing method of diamond abrasive grinding wheels and found that this method would not reduce the surface grinding quality in the hybrid technology of electrochemical treatment. [PERSON] et al. [21] studied the electric-contact discharge after dressing to ensure the uniformity of the height of the abrasive grain protrusion. [PERSON] et al. [22] found that the electric spark discharge current affected the height of diamond abrasive grains protruding from the metal bond and the size of the chip holding space and that the pulse width affected the surface roughness of the diamond abrasive grinding wheel. [PERSON] et al. [23] carried out EDM truing experiments on the small ball-end fine diamond abrasive grinding wheel and analyzed the relationship between the electrical parameters and contour accuracy; a reduction in the graphitization of the diamond abrasive grinding wheels, and ideal dressing quality was achieved.  
The surface effect of electric machining truing aluminum-based diamonds is shown in Figure 8 [24]. It was found that the surface of the diamond abrasive grains was smooth and bright, and the grinding edges were sharp. The EDM truing method had a high dressing efficiency of approximately 60\(\sim\)70% and had certain advantages in machining workpieces that could not be machined by conventional machine tools, but it had disadvantages in machining non-conductive materials. Moreover, the power supply of the electrolytic machining method was expensive and the EDM truing method was difficult to process due to the existence of a discharge gap. Especially for large abrasive grains, it was difficult to process. Therefore, lasers began to be applied to truing diamond abrasive grinding tools.  
Figure 8: Surface renderings of the aluminum-based diamond before and after Electrolytic in-process dressing technology (ELID) processing [24].