Introduction to New Processing Techniques for Grinding and Polishing Discs

Commonly used grinding disc materials include cast iron, glass, ceramics, etc. A grinding disc is a carrier used for coating or embedding abrasives, allowing the abrasive particles to play a cutting role; It is also a forming tool for grinding surfaces. The grinding disc itself is mutually trimmed with the workpiece during the grinding process, and the geometric accuracy of the grinding disc itself is "copied" to a certain extent to the workpiece, so it is required that the machining surface of the grinding disc has high geometric accuracy. The requirements for abrasives mainly include: ① the Hardness is generally lower than the workpiece material, the organization is uniform and dense, there are no impurities, foreign matters, cracks and defects, and there are certain abrasives embeddedness and immersion. ② Reasonable structure, with good rigidity, accuracy retention, and wear resistance. The working surface should have high geometric accuracy Good chip removal and heat dissipation.

In order to obtain a good grinding/polishing surface, it is sometimes necessary to notch the surface of the grinding/polishing disc. The shapes of grooves include radial, grid, concentric, and spiral shapes. The shape, width, depth, and spacing of the groove should be selected based on the quality of the workpiece material, ceramic injection molding, shape, and machining accuracy of the grinding surface. Slotting on the surface of the grinding tool has the following effects: ① It can store excess abrasive particles in the groove to prevent the accumulation of abrasive aluminum nitride and damage to the surface of the workpiece. ② As a channel for supplying abrasive particles to the workpiece during processing. ③ As a channel for timely chip removal, prevent scratches on the grinding surface.

In recent years, a kind of fixed abrasive grinding technology has emerged. Its grinding plate is made by mixing diamond or cubic Boron nitride abrasive with cast iron powder, sintering into small thin pieces, or fixing abrasive particles on metal sheets by electroforming, and then pasting these small thin pieces on the base plate with epoxy resin. Fixed abrasive grinding discs are suitable for precision grinding of brittle materials such as ceramics, silicon wafers, crystals, etc. The surface accuracy of the grinding disc is well maintained, and the grinding efficiency of industrial ceramics is high. Except for the use of hard polishing discs for polishing diamonds and other materials, soft polishing discs are used for polishing. The precision and accuracy retention of polishing discs are the guarantee of high-precision polishing. Although the processing deterioration layer and surface roughness of the polished surface of soft polishing discs are small, the polishing discs are prone to wear and poor in maintaining surface accuracy, which can cause the specimen to experience "edge collapse" phenomenon. Therefore, when requiring high flatness or angular shape accuracy, soft metals such as copper or tin can be used as polishing discs. When good surface roughness is required, Viscoelasticity polishing cloth such as polyurethane or felt is often used. To ensure the high accuracy of polishing processing, the following measures can be taken: ① Use wear-resistant and deformable polishing discs as much as possible; ② Discard worn and deformed polishing discs; ③ Electroceramics correct the wear profile. The shape of the polishing disc can be adjusted using the trimming mechanism on the device, or it can be adjusted using a standard flat plate and polishing disc.

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