Grinding is divided into surface grinding and internal and external grinding, which is an important means to ensure the plane accuracy and internal and external accuracy of precision mechanical parts. Then grinding
What are the characteristics? Let's elaborate from several aspects.
The grinding cutting edge is irregular, and its shape and distribution are in an irregular random state. Its shape, size and position are different. Precision mechanical parts plus
Working hours, the cutting thickness is thin, generally less than 5 microns. Power grinding is different from creep feed grinding. The former has more grinding energy than the latter, which is 10 times more than milling
That is to say, the cutting energy consumption is large.
Grinding is different from the general precision machining process. It is not a pure mechanical process. There is high temperature and high contact pressure at the interface between the abrasive grains and the workpiece, and the temperature is close to
The melting point of the workpiece material and the interface pressure can reach the level of plastic deformation flow on the abrasive surface.
The grinding speed is fast, tens to hundreds of times higher than other cutting speeds. For metal removal, it has a high removal rate, and the grinding temperature
It is also high. In order not to touch the grinding wheel when machining precision mechanical parts, there are special requirements for the grinding fluid during grinding.
When machining precision mechanical parts, the grinding process is generally considered as a three-stage process, namely, the thermal stress generated in the sliding elastic friction and deformation stages; Plough - quilt
Internal friction of processing materials, the surface layer of workpiece not only has thermal stress, but also has deformation stress due to elastic and plastic deformation, which affects precision hardware processing parts
Surface roughness and surface processing quality, and no chips flow out on the front edge of the abrasive grain; Cutting - the workpiece material slides along the shear plane to form chips, which are produced on the workpiece surface
Heat generating stress and deformation stress.
The grinding temperature is higher than other cutting temperatures, and the workpiece can be considered in three parts: the temperature of grinding point - the temperature of the part where the abrasive cutting edge contacts with the chip,
It is the highest point of grinding heat source and temperature, which affects the metallographic structure and physical and mechanical properties of the surface layer, and is related to abrasive wear and cutting fusion. Grinding zone temperature
——The average temperature of the contact area between the grinding wheel and the workpiece is closely related to grinding burns and grinding cracks. The temperature rise of the workpiece is generally small, only for dimensional accuracy and geometric tolerance
influential. About 80% of the cutting heat is transferred to the workpiece, 4-8% to the abrasive chips, and the rest to the grinding wheel.