Advanced Ceramic Grinding Technology

Grinding processing usually refers to the use of micrometer sized abrasive particles with a hardness greater than that of the processed material, and the micro cutting and rolling effects generated by the hard grinding disc to remove trace materials from the processed surface, so as to achieve the required shape and dimensional accuracy of the workpiece, reduce surface roughness, and reduce the processing deterioration layer.

1. Grinding mechanism

Advanced ceramic materials are hard, brittle, and difficult to machine materials. During the grinding process of these materials, the removal of the processed material relies on the rolling or micro cutting action of the abrasive particles.

When grinding hard and brittle materials, it is important to control the size and uniformity of the cracks generated. On the one hand, it is necessary to ensure that there is no significant damage to the surface during processing; On the other hand, in order to improve processing efficiency, it is necessary to promote small crushing. By selecting the particle size of abrasive particles and controlling the uniformity of particle size, it is possible to avoid particularly large machining defects.

2 Characteristics of Grinding Processing

(1) Due to the distribution of numerous abrasive particles between the workpiece and the grinding tool, the load on a single abrasive particle is very small. By controlling the appropriate processing load range, a back cutting amount less than l anal m can be obtained, achieving micro cutting of the workpiece material.

(2) According to the principle of evolution, when the grinding tool comes into contact with the workpiece, it can automatically select local protrusions for processing under non mandatory grinding pressure. Therefore, only the materials at the protrusions of the two can be cut off, so that the grinding tool and the workpiece can repair each other and gradually improve accuracy. Addition of ultra precision grinding_ The accuracy is almost independent of the motion accuracy of the machine tool that constitutes relative motion. It is mainly determined by factors such as the contact properties and pressure characteristics between the workpiece and the grinding tool, as well as the shape of the relative motion trajectory. Under appropriate conditions, the machining accuracy can exceed the accuracy of the machine tool itself, so this type of machining is called evolutionary machining. In order to obtain an ideal machining surface, it is required to:

① The grinding tool and workpiece can be mutually trimmed;

② Try to ensure that the relative motion trajectories of each point on the machined surface and the grinding disc do not repeat, in order to reduce the "copying" phenomenon caused by the geometric shape error of the grinding tool surface on the surface shape of the workpiece, and at the same time, reduce the depth of scratches and surface roughness;

③ On the premise of ensuring that the grinding tool has an ideal geometric shape, using a floating grinding disc can ensure surface processing accuracy.

(3) In grinding, due to the uneven shape of each abrasive particle and the randomness of its distribution, multi-directional cutting can be achieved when the abrasive particles slide and roll on the workpiece, and the cutting opportunity and cutting edge breakage rate of all abrasive particles are equal, achieving automatic sharpening. By increasing the contact area, contact pressure, and relative movement distance between the workpiece and the abrasive particles, reducing the half apex angle of the abrasive cone can improve machining efficiency; By reducing the size of abrasive particles, the contact pressure between the workpiece and abrasive particles, and the volume fraction of abrasive particles, as well as increasing the yield point of the workpiece, the half apex angle of the abrasive cone, and the abrasive particle rate, surface roughness can be reduced.

Website: https://www.zhengtaifeng.com/