High precision cross roller bearing has excellent rotation accuracy, has been widely used in industrial robot joint parts or rotating parts, machining center rotary table, manipulator rotary part, precision rotary table, medical instruments, measuring instruments, IC manufacturing devices. These precision instruments for cross roller bearing precision requirements are relatively high, so in the production, processing also requires higher technology. In particular, the polishing treatment of the bearing surface, which is an important factor affecting the accuracy of cross roller bearing, let's talk about the polishing process of cross roller bearing.
The polishing of cross roller bearings is a process of finishing the surface of parts with fine abrasive particles and soft tools. In the process of polishing, the interaction between abrasive particles and workpiece surface has three states: sliding, ploughing and cutting. In these three states, grinding temperature and grinding force are increasing. Because the abrasive particles are attached to the soft matrix, so under the action of grinding force, the abrasive particles will be retracted to the softer matrix in different degrees, resulting in tiny scratches on the surface of the workpiece and fine chips. The sliding and ploughing action of the abrasive particles on the surface of the workpiece makes the surface of the workpiece plastic flow, improves the microscopic roughness of the workpiece surface to a certain extent, forms a continuous smooth surface, so that the surface of the workpiece to achieve mirror effect.
Due to the small thermal conductivity, high toughness and small elastic modulus of bearing steel, the following problems often exist in grinding of bearing steel:
1. High grinding force and high grinding temperature
2, grinding chip is difficult to cut off, grinding grain is easy to blunt
3, the workpiece is prone to deformation
4. Grinding debris is easy to adhere to grinding wheel
5, the processing surface is easy to burn
6, work hardening trend is serious
The hard elastic structure of polyvinyl acetal is used as abrasive carrier and a new polishing tool is made by casting method. Due to the characteristics of the bond itself, grinding wheel has its unique characteristics, the main characteristics are:
1, high porosity. It is spongy structure, rich in tiny pores, low grinding heat, not easy to burn workers.
2, elastic, strong polishing ability.
3, not easy to plug. It is suitable for polishing all kinds of metal and non-metal, especially for polishing stainless steel, copper alloy and other hard grinding materials and parts of complex surface, used to replace adhesive wheel, cloth wheel, can improve the polishing efficiency.
Grinding wheel speed, workpiece speed and cutting depth all have great influence on surface polishing. The grinding speed is different, the workpiece surface quality is different. When grinding stainless steel material, choose higher grinding wheel speed, in order to improve the cutting ability of grinding wheel, but the grinding wheel speed is too high, grinding scratch more, grinding wheel is easy to jam, workpiece surface is easy to burn. The workpiece speed changes with the grinding wheel speed. When the grinding wheel speed increases, the workpiece speed also increases, and when the grinding wheel speed decreases, the workpiece speed also decreases. When the cutting depth is too small, the abrasive particles can not cut into the workpiece surface, the efficiency is too low. When the cutting depth is too large, the total grinding heat will increase, and it is easy to produce burn phenomenon.
Post time: Mar-28-2022