According to the production process: it can be divided into injection cover and compression cover;
The production process of injection molding cover is as follows:
The sucking machine sucks the mixed materials into the barrel of the injection molding machine, heats them in the barrel to melt and plasticize, injects them into the mold cavity, cools and shapes them in the cavity, demoulds them, and then cuts and cushions them to complete the production of the injection molding cover.
The production process of the pressed plastic cover is as follows:
The suction machine sucks the mixed materials into the barrel of the press moulding machine. After the barrel is heated to the semi melting and plasticizing state, the mixed materials are extruded into the mould cavity quantitatively. The upper and lower moulds are closed, molded, cooled and shaped, demoulded, and then cut and padded to complete the production of the press moulding cover. Comparison:
(1) the injection cover needs to heat the material to the molten flow state, and the temperature is about 250 ℃; the injection cover only needs to heat to about 180 ℃, and the energy consumption of the injection cover is higher than that of the injection cover;
(2) the processing temperature is low, the shrinkage is small, and the cover size is more accurate;
(3) fill all mould cavities at one time for injection molding, and extrude one bottle cap material at a time for compression molding. The extrusion pressure is very small, but the injection pressure is high;
(4) the injection mold has a large volume, and the replacement of a single mold cavity is troublesome; each mold cavity of the compression molding is relatively independent and can be replaced separately;
(5) the press molding machine is a special machine for bottle cap, which is specially designed for the release of the bottle cap; the injection molding machine for bottle cap is basically not specially designed for the bottle cap, so the press molding cover can be made into a bell mouth, with a high rate of cover hanging, which users like to use.