Tips of injection molding process of fireproof ABS material
Fireproof ABS is a kind of common fireproof material, which has a wide range of application at present. The main reason is that it is easy to produce and process, has fast fireproof effect, and has good gloss. Usually, the processing temperature of fireproof ABS is about 200 ℃. Because of the addition of other materials, the processing method and temperature of this raw material are different from those of pure fireproof ABS
1. Drying treatment must be done before production and processing, drying temperature: 70 ~ 90 ℃, 2 ~ 4 hours, drying before production and processing. The moisture content of fireproof ABS alloy material is low. If the storage time is not long after drying, it can be directly injected without drying again, and the injection products will not have splash surface.
2. Injection molding machine machinery and equipment, screw parts as far as possible to choose air-cooled machinery and equipment, if not, there may be high temperature and cause the decomposition of raw materials can not be injected, that is to say, coke and other phenomena.
3. After injection molding, the demoulding process should not be too fast. Take 2kg product as an example, the demoulding time should be 75s ~ 80s, otherwise the surface of the product will bulge.
4. After injection molding, clean the mold with other raw materials (such as polypropylene thinner) and apply antirust oil to prevent ABS alloy from corroding screw and mold. If it is necessary to replace the mold or maintain the mold for a long time, the fireproof ABS alloy should not be heated and retained in the screw for more than 40 minutes to prevent decomposition or even carbonization.
5. Taking 2kg product as an example, the inner diameter of nozzle should be 3.2mm, and the inner surface should be smooth.
6. Recommended production and processing temperature: 170 ~ 180 ℃ for injection nozzle, 5 ℃ for each zone in the following sections, and the specific implementation shall be adjusted according to the actual production and processing conditions. The set temperature of production and processing should not be in place in one step. It is recommended to slowly rise from 160 ℃ until the injection product is good.
7. A little bit of back pressure is OK, but not too much.
8. For the selection of machinery and equipment, it is recommended to use a machine twice the gram weight of the injection molding product. If the net weight of the injection molding product is 1000g, the injection molding machinery and equipment should be 2000g.