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Injected Parts Processing Tips
Wishsino International Group Limited | Updated: May 19, 2017

 Injected Parts The polishing of plastic molds is very different from the surface polishing required in other industries. Strictly speaking, the polishing of molds should be called mirror processing. It not only has a high demand for polishing itself but also has a high standard for surface flatness, smoothness and geometric accuracy. Surface polishing generally requires only to obtain a bright surface. The standard of mirror processing is divided into four levels: AO = Ra0.008μm, A1 = Ra0.016μm, A3 = Ra0.032μm, A4 = Ra0.063μm, it is difficult to precisely control the geometric accuracy of the part due to electrolytic polishing and fluid polishing , And chemical polishing, ultrasonic polishing, magnetic polishing and other methods of surface quality and fail to meet the requirements, so the precision mold mirror processing or mechanical polishing mainly. 2.1 Mechanical polishing basic procedures

In order to obtain high-quality polishing effect, the most important thing is to have a high-quality Whetstone, sandpaper and diamond polishing paste and other polishing tools and accessories. The choice of polishing process depends on the pre-processed surface conditions, such as machining, EDM, grinding and so on. The general process of mechanical polishing is as follows:

(1) rough throwing

Injected Parts After milling, EDM, grinding and other processes can choose the speed of 35 000-40 000 rpm in the rotating surface polishing machine or ultrasonic grinding machine for polishing. Commonly used methods have the use of diameter Φ3mm, WA # 400 wheels to remove the white spark layer. Followed by hand-oil-stone grinding, strip of lime plus kerosene as a lubricant or coolant. The general use order is # 180 ~ # 240 ~ # 320 ~ # 400 ~ # 600 ~ # 800 ~ # 1000. Many mold manufacturers have chosen to start from # 400 in order to save time.

(2) semi-fine throwing

Injected Parts Semi-fine polishing mainly uses sandpaper and kerosene. The number of sandpaper is: # 400 ~ # 600 ~ # 800 ~ # 1000 ~ # 1200 ~ # 1500. In fact, # 1500 sandpaper only for hardened die steel (52HRC above), and not for pre-hardened steel, because it may lead to pre-hardened steel surface burns.

(3) fine throwing

Injected Parts The main use of diamond polishing paste. The grinding order is usually 9 μm (# 1800) to 6 μm (# 3000) to 3 μm (# 8000) if the polishing is carried out using a polished cloth round diamond or abrasive paste. 9μm diamond grinding paste and polishing cloth wheel can be used to remove the # 1200 and # 1500 sandpaper leaving the hair wear marks. Followed by polishing with a felt and a diamond abrasive paste in the order of 1 μm (# 14000) to 1/2 μm (# 60000) to 1/4 μm (# 100000).

Accuracy requirements in more than 1μm (including 1μm) polishing process in the mold processing workshop in a clean polishing room can be carried out. If you want to carry out more sophisticated polishing must be an absolutely clean space. Dust, smoke, dandruff and mouth foams are likely to be scrapped after a few hours of work to get the high precision polished surface. 2.2 mechanical polishing to pay attention to the problem