Injection Mold Mechanical Polishing Process

Injection mold polishing uses tools: oil stone, sandpaper, polishing paste, wool wheel, etc. We use these tools to polish the cavity surface of the injection mold, so that the working surface of the mold can be as bright as a mirror. The process is called polishing. If you want to obtain a high-quality polishing effect, you generally need to use high-quality polishing tools and accessories such as oilstone, sandpaper, and diamond abrasive paste. The choice of polishing procedure depends on the surface condition after pre-processing, such as machining, EDM, grinding and so on. The general process of mechanical polishing is as follows:

1. Rough throwing

The surface after milling, EDM, grinding and other processes can be polished by a rotary surface polishing machine or an ultrasonic grinding machine with a rotation speed of 35 000-40 000 rpm. The commonly used method is to use a wheel with a diameter of Φ3mm and WA # 400 to remove the white electric spark layer. Then manual whetstone grinding, strip whetstone plus kerosene as lubricant or coolant. The general order of use is #180 ~ #240 ~ #320 ~ #400 ~ #600 ~ #800 ~ #1000. Many moldmakers choose to start with #400 to save time.

2. Semi-fine polishing

Semi-fine polishing mainly uses sandpaper and kerosene. The numbers of sandpaper are: #400 ~ #600 ~ #800 ~ #1000 ~ #1200 ~ #1500. In fact, #1500 sandpaper is only suitable for hardened mold steel (above 52HRC), not for pre-hardened steel, because it may cause burns on the surface of pre-hardened steel.

3. Fine polishing

Fine polishing mainly uses diamond abrasive paste. If the polishing cloth wheel is mixed with diamond grinding powder or grinding paste for grinding, the usual grinding sequence is 9μm (#1800) ~ 6μm (#3000) ~ 3μm (#8000). 9μm diamond paste and polishing cloth wheel can be used to remove hair-like wear marks left by #1200 and #1500 sandpaper. Then use sticky felt and diamond abrasive paste for polishing, the order is 1μm (#14000) ~ 1/2μm (#60000) ~ 1/4μm (#100000).

The polishing process whose precision is required to be above 1 μm (including 1 μm) can be carried out in a clean polishing room in the mold processing workshop. For more precise polishing, an absolutely clean space is required. Dust, smoke, dandruff and drool can all ruin a highly polished finish after hours of work.

Taizhou Minghuang Plastic Mold Co., Ltd. is a professional Plastic Injection Mold Manufacturers. If you need it, you can click the official website to contact us. We are willing to answer you for more information.