Precautions for parts grinding

There are three main types of machine tools used in grinding: surface grinders, internal and external cylindrical grinders, and tool abrasives. During finishing grinding, grinding deformation and grinding cracks must be strictly controlled. Even very small cracks will be exposed in the subsequent processing and use. Therefore, the feed of the fine grinding should be small, not large, the coolant should be sufficient, and the parts with the size tolerance within 0.01mm should be ground as much as possible at a constant temperature. It can be seen from the calculation that when the temperature difference of 300mm steel parts is 3℃, the material will have a change of about 10.8μm, 10.8u003d1.233 (1.2μm/℃ per 100mm deformation), and the influence of this factor must be fully considered in each finishing process. .

It is very important to choose an appropriate grinding wheel during fine grinding. For the high vanadium and high molybdenum condition of the mold steel, the GD single crystal corundum grinding wheel is more suitable. When processing cemented carbide and high quenching hardness materials, it is preferred Organic bond diamond grinding wheels, organic bond grinding wheels have good self-grinding properties, and the roughness of the ground workpieces can reach Rau003d0.2μm. In recent years, with the application of new materials, CBN grinding wheels, also known as cubic boron nitride The wheel shows a very good machining effect. It is better than other types of grinding wheels for finishing on CNC forming grinding, coordinate grinding, and CNC internal and external cylindrical grinding machines. During the grinding process, care should be taken to dress the grinding wheel in time to keep the grinding wheel sharp. When the grinding wheel is passivated, it will rub and squeeze on the surface of the workpiece, causing burns on the surface of the workpiece and reducing its strength.

Most plate parts are processed by surface grinders. In the process, a long and thin sheet part is often encountered, which is difficult to process. Because during processing, under the action of magnetic force, the workpiece deforms and sticks to the surface of the worktable. When the workpiece is removed, the workpiece will return to deformation. The thickness measurement is consistent, but the parallelism cannot meet the requirements. Solution Magnetic isolation grinding method can be used. Contour blocks are used to pad under the workpiece during grinding. Blocks on all sides are used to resist the death. During processing, small feeds and multiple smooth knives can be used. After one side is processed, the contour blocks can be directly absorbed and processed. , This can improve the grinding effect and meet the requirements of parallelism.

Shaft parts have a rotating surface, and their processing widely uses internal and external cylindrical grinders and tool grinders. During the processing, the headstock and the center are equivalent to the bus bar. If there is a runout problem, the processed workpiece will also have this problem, which will affect the quality of the parts. Therefore, the headstock and the center must be inspected before processing. When grinding the inner hole, the coolant should be poured to the grinding contact position to facilitate the smooth discharge of the grinding. For processing thin-walled shaft parts, it is best to use a clamping technology table, and the clamping force should not be too large, otherwise it is easy to produce inner triangular deformation on the circumference of the workpiece.