Carbide knife grinding
Although carbide cutting knives have high wear resistance, but because of its high hardness, brittleness and small thermal conductivity, it brings great difficulties to grinding. Carbide knife cost is high, due to improper sharpening caused by scrap is a pity.
Because the hardness of tungsten carbide is high, it requires a large grinding pressure, because of its small thermal conductivity, and does not allow excessive heat to be generated, so it is required that the grinding wheel should first be selected when grinding, followed by the grinding wheel and better self-sharpening, in addition, there must be a reasonable grinding process. Only in this way can there be good heat dissipation conditions to reduce the generation of grinding cracks.
When using green silicon carbide grinding wheels, especially to avoid overheating, for this purpose, you can use coolant. The composition of the coolant is 2%-3% soda water solution or 3%-5% emulsion. Coolant supply must be sufficient, do not intermittent or drip supply.
In order to avoid overheating, the grinding wheel should be repaired frequently. When the grinding wheel is very loud and the grinding surface is luminous, it indicates that the grinding wheel is blunt, and the grinding wheel dresser should be applied.
Do not exert too much force when sharpening the edge. Too much force, too much friction, the grinding temperature rises sharply, the alloy will be red, and even burst.
Pay attention to the first part of the knife body contact the grinding wheel, and then run in the gold part. When withdrawing the knife, the alloy part should be left first, so as to avoid damaging the alloy.
The direction of rotation of the grinding wheel should be strictly controlled, and must be grinding from the cutting edge to the knife body, not from the knife body to the cutting edge; The front should be ground first and then the back to prevent cracking of the cutting edge. When sharpening multi-tooth knives (such as circular saw blades) can first grind the front of each tooth, and then grind the back of each tooth; First rough grinding, then fine grinding. Coarse grinding wheel with particle size 46, fine grinding wheel with particle size 80-100.
When grinding carbide knives with silicon carbide grinding wheel, intermittent grinding method can also be used to avoid overheating. Intermittent grinding is to open a certain size and a certain number of grooves at the working part of the silicon carbide grinding wheel. Because these grooves on the grinding wheel can not only improve the cooling effect of the coolant, but also enhance the self-sharpening ability of the grinding wheel.
When grinding carbide knives with diamond grinding wheel, the total grinding allowance should be controlled below 0.1-0.2mm, and the diamond consumption of large grinding wheel is large and the cost is too high.
