The forging blanks rely mainly on the rotating main motion and the feed motion of the tool on the lathe to complete the cutting action. Therefore, whether the selection of the turning angle is reasonable and the angle of the turning of the turning tool is correct will directly affect the processing quality and cutting efficiency of the forging.
During the cutting process, due to the sharp friction and cutting heat of the rake face and the flank face of the turning tool, the cutting edge of the turning tool becomes dull and loses the cutting ability. Only the sharpening can restore the cutting. The sharpness of the cutting edge and the correct angle of the car. Therefore, the mechanic must not only understand the cutting principle and the knowledge of the reasonable choice of the angle of the turning tool, but also must master the sharpening skills of the turning tool.
The sharpening of the turning tool is divided into mechanical sharpening and manual sharpening. The mechanical sharpening efficiency is high, the quality is good, and the operation is convenient. At present, small and medium-sized forging production factories still use manual sharpening. Therefore, the lathe must master the technology of manual sharpening.
At present, the commonly used grinding wheels are aluminum oxide and silicon carbide. When grinding, the grinding wheel must be selected according to the cutting tool material.
1. Alumina grinding wheel
The alumina grinding wheel is mostly white, and its sand has good toughness and is relatively sharp, but the hardness is slightly lower (referring to the easy removal of the abrasive grains from the grinding wheel), and it is suitable for sharpening the high-speed steel turning tool and the shank part of the hard alloy. Alumina grinding wheels are also called corundum grinding wheels.
2, silicon carbide grinding wheel
The silicon carbide grinding wheel is mostly green, and its sand has high hardness and good cutting performance, but it is brittle and suitable for sharpening hard alloy turning tools.
The thickness of the grinding wheel is expressed in terms of particle size. GB 2477-83 specifies 41 particle size numbers, coarse grain size (large grain size) for coarse grinding, and fine particle size (small particle size) for fine grinding.
Precautions for turning sharpening in forging machining
1. Wear protective glasses when sharpening.
2. The newly installed grinding wheel must undergo strict inspection and can only be used after passing the test.
3. The grinding surface of the grinding wheel must be regularly trimmed.
4. When sharpening the knife, the operator should try to avoid facing the grinding wheel to stand on the side of the grinding wheel. This will not only prevent the sand from flying into the eyes, but more importantly, it will prevent the injury caused by the damage of the grinding wheel. A grinder is operated by one person, and no one is allowed to gather together.
5, when sharpening the knife, do not use too much force to prevent slipping and hurt your hand.
6. When using flat grinding wheel, try to avoid sharpening on the end face of the grinding wheel.
7. When grinding high-speed steel turning tools, it should be cooled in time to prevent the edges from being annealed, resulting in a decrease in hardness. When sharpening a carbide cutter, the blade body cannot be cooled in water to prevent the blade from collapsing due to quenching.
8, force grinding and crusting, should close the grinder power supply with Yin.