Views: 90 Author: Site Editor Publish Time: 2022-09-26 Origin: Site
Grinding of ceramics usually refers to the use of micron-sized abrasive grains, which are harder than ceramic materials, to achieve micro-cutting and rolling action under the action of hard grinding discs to remove a small amount of material from the surface to be machined, so that the shape and dimensional accuracy of the workpiece reaches the required value, and to reduce the surface roughness and reduce the processing degradation layer.
In the grinding process of hard and brittle materials, the removal of the material to be machined relies on the rolling action of the abrasive grains or the micro-cutting action.
When grinding hard and brittle materials, it is important to control the size and uniformity of the cracks produced. On the one hand, it is important to ensure that no major damage occurs to the surface during processing; on the other hand, it is necessary to promote micro-cracking in order to improve processing efficiency. Particularly large machining defects can be avoided by selecting the size of the abrasive grain and controlling the uniformity of the size.
(1) Micro-cutting As there are numerous abrasive grains distributed between the workpiece and the grinding tool, the load on individual abrasive grains is very small, and controlling the appropriate range of machining loads, it is possible to obtain a back-eating amount of less than l anal m to achieve micro-cutting of the workpiece material.
(2) According to the evolutionary principle of forming When the grinding tool is in contact with the workpiece, under the action of non-compulsory grinding pressure, it can automatically select the local convexity for processing, so that only the material of the two projections is removed, so that the grinding tool and the workpiece can trim each other and gradually improve the accuracy. The accuracy of ultra-precision grinding is almost independent of the accuracy of the machine motion, but is mainly determined by the nature of the contact between the workpiece and the grinding tool and the pressure characteristics, as well as the shape of the relative motion trajectory. Under the right conditions, the machining accuracy can exceed the accuracy of the machine tool itself, so called this kind of machining for evolutionary machining. In order to obtain the ideal machined surface, it is required that.
① the ability of the research tool and the workpiece to trim each other.
②try to make the machined surface points and the relative motion of the grinding disc trajectory does not repeat, in order to reduce the geometry of the surface of the grinding tool error on the shape of the workpiece surface caused by the "copy" phenomenon, while reducing the depth of scratches, reduce surface roughness.
(3) in the premise of ensuring that the grinding tool has the ideal geometry, the use of floating grinding discs, can ensure the surface machining accuracy.
(3) Multi-edge multi-directional cutting In the grinding process, due to the shape of each abrasive grain is not exactly the same, as well as the randomness of the distribution, when the abrasive grain does sliding and rolling on the workpiece, multi-directional cutting can be achieved, and all the abrasive grains have equal cutting opportunities and cutting edge breakage rate, so that automatic sharpening can be achieved. By increasing the contact area, contact pressure and relative travel distance between the workpiece and the abrasive grains, and by reducing the conical half-top angle of the abrasive grains, the machining efficiency can be increased; by reducing the abrasive grain size, the contact pressure between the workpiece and the abrasive grains and the abrasive grain volume rate, and by increasing the yield point, the conical half-top angle and the abrasive grain rate of the workpiece, the surface roughness can be reduced.
