# Study on Preparation and Processing Properties of Mechano-Chemical Micro-Grinding Tools
## 2 Design of Mechano-Chemical Micro-Grinding Tools  
Unlike traditional grinding processing, which uses an abrasive higher than the hardness of the material to be processed to remove the brittleness or plasticity of single-crystal silicon, mechanochemical grinding achieves material removal through the solid-solid phase chemical reaction between the abrasive and additives and the surface of the material, as well as the synergistic effect of mechanical stress [16]. Therefore, the design of micro-grinding tools usually needs to meet four conditions:  
1. The hardness of the abrasive is lower than that of the material being processed;
2. The abrasive can undergo a solid-solid phase chemical reaction with the processed material;
3. Abrasive additives can directly react with the material to be processed or can promote solid-solid phase chemical reactions;
4. Abrasive additives can adjust the porosity ratio of the abrasive. Based on the above conditions, this paper made a reasonable selection of the microstructure components of the abrasive in three aspects: abrasives, binders, and additives, and reflected the microstructure of the abrasives through the content ratio. Cerium oxide was selected as an abrasive, which has a lower hardness than single-crystal silicon, has an excellent grinding effect, and is not easy to clog [17]. The phenolic resin was selected as the binder. The micro-grinding tools made of it usually have good elasticity and self-sharpening, and it is easy to obtain a good processing surface. Sodium bicarbonate, zinc sulfate, calcium oxide, and copper powder were selected as additives, which can enhance the chemical activity of the abrasive, thereby improving the grinding performance of mechano-chemical micro-grinding tools to achieve the purpose of high-quality processing [18]. The main functions of each component of the additive are as follows. 1. Sodium bicarbonate: Sodium bicarbonate will decompose under hot pressing conditions of about 190 \({}^{\circ}\)C to produce carbon dioxide gas and sodium carbonate. Carbondioxide gas can make certain pores in the micro-grinding tools, thereby ensuring the self-sharpening of the micro-grinding tools. The sodium carbonate produced by decomposition can be used as an active agent to weaken the adhesion between the cerium oxide abrasive and the binder, thereby enhancing the self-sharpening of the micro-grinding tools;
2. Zinc sulfate: Adding zinc sulfate to the abrasive can make the additive particles adsorb around the abrasive. After the abrasive particles adsorb the particles, they are more likely to be broken in the mechanical collision during grinding, thereby increasing the specific surface area of the abrasive particles and improving the chemical activity;
3. Calcium oxide: Calcium oxide acts as a curing agent in additives and can promote the curing of the resin. Furthermore, because of its good heat resistance and high bonding strength, it can play a hygroscopic role in micro-grinding tools;
4. Copper powder: Because copper powder has good thermal conductivity, the heat generated by the interaction between the abrasive and the workpiece during the grinding process can be conducted through the copper powder, improving the overall heat resistance of the micro-grinding tools. The design size of the individual micro-grinding tool is 10 mm in diameter and 8 mm in height, and the composition ratio is shown in Table 1.  
After calculating the amount of each ingredient added, follow these steps to make a micro-abrasive:  
1. Screening: After grinding the powder, use the #400 screen for screening, filter out larger particles, and improve the uniformity of the powder, so that the components can be mixed more evenly;
2. Weighing: To prevent the loss of raw materials in the subsequent baking and mixing process, 120% of the theoretical feeding amount calculated by each component should be weighed after the screening;
3. Drying: To prevent the powder's moisture from affecting the abrasive's performance, the weighed powder should be dried.