In order to avoid scratches and burns to the surface of the workpiece, special care must be taken when polishing with ා 1200 and ා 1500 sandpaper. Therefore, it is necessary to load a light load and use two-step polishing method to polish the surface. When each type of sandpaper is used for polishing, it should be polished twice along two different directions, with each rotation of 45 ° to 90 ° between the two directions.
Diamond grinding and polishing should pay attention to the following points:
(1) This kind of polishing must be carried out under light pressure as far as possible, especially when polishing pre hardened steel parts and polishing with fine grinding paste. When polishing with ා 8000 grinding paste, the common load is 100 ~ 200g / cm2, but it is difficult to maintain the accuracy of this load. To make this easier, make a thin, narrow handle on the wood, such as adding a piece of copper, or cut a part of the bamboo strip to make it softer. This helps to control the polishing pressure to ensure that the die surface pressure is not too high.
(2) When using diamond grinding and polishing, not only the working surface is required to be clean, but also the worker’s hands must be carefully cleaned.
(3) Each polishing time should not be too long, the shorter the time, the better the effect. If the polishing process is too long, it will cause “orange peel” and “pitting”.
(4) In order to obtain high quality polishing effect, polishing methods and tools which are easy to heat should be avoided. For example: polishing wheel polishing, the heat generated by polishing wheel can easily cause “orange peel”.
(5) When the polishing process stops, it is important to ensure that the surface of the workpiece is clean and that all abrasives and lubricants are carefully removed, and then a layer of mold antirust coating shall be sprayed on the surface.
At present, mechanical polishing is still the main factor affecting the quality of mold polishing. In addition, it is also related to mold material, surface condition before polishing and heat treatment process. High quality steel is the prerequisite to obtain good polishing quality. If the surface hardness of steel is uneven or there are differences in characteristics, polishing difficulty will often occur. All kinds of inclusions and pores in the steel are not conducive to polishing.
3.1 the influence of different hardness on the polishing process increases the difficulty of grinding, but the roughness decreases after polishing. Due to the increase of hardness, the polishing time required to achieve lower roughness increases correspondingly. At the same time, the possibility of over polishing decreases with the increase of hardness.
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