The plastic mold is mainly composed of three parts: pouring system, forming parts and structural parts. Among them, the pouring system and molding parts are the parts that are in direct contact with plastics and change with plastics and products, and are the parts of plastic molds that are complex and vary greatly, requiring high processing finish and accuracy.

The plastic mold pouring system refers to the part of the flow path before the plastic enters the cavity from the nozzle, including the main channel, cold hole, diverter channel and gate. Molded parts refer to various parts that form the shape of the product, including moving dies, fixed dies and cavities, cores, molding rods and exhaust ports.

First, the mainstream path

It is a passage in the mold connecting the injector nozzle to the diverter or cavity. The top of the main channel is concave to connect with the nozzle.

The inlet diameter of the main channel should be slightly larger than the nozzle diameter (0.8mm) to avoid overflow and prevent the blockage caused by inaccurate connection between the two.

The diameter of the import depends on the size of the product, generally 4-8mm. The diameter of the main channel should be expanded inward at an Angle of 3° to 5° to facilitate the demoulding of the flow path.

Two, cold hole

It is a hole located at the end of the main stream to trap the cold material generated between two injections at the end of the nozzle, thereby preventing the blockage of the diverter or gate. If the cold material is mixed into the cavity, it is easy to produce internal stress in the manufactured product.

The diameter of the cold hole is about 8-l0mm and the depth is 6mm. In order to facilitate demoulding, its bottom is often borne by the demoulding rod. The top of the ejector rod should be designed as a zigzag hook shape or a sunken groove, so that the main channel can be pulled out smoothly during the ejector.

Three, diversion channel

It is a channel connecting the main channel and each cavity in the multi-groove mold. In order to fill each cavity with molten material at an equal speed, the arrangement of the diverter on the mold should be symmetrical and equidistant. The shape and size of the diverter section affect the flow of plastic melt, the release of product and the difficulty of mold manufacturing.

If the flow of the same amount of material, then the circular section of the flow channel resistance is less. However, because the cylindrical flow channel is smaller than the surface, it is unfavorable to the cooling of the flow channel, and the flow channel must be opened on the two half die, which is laborious and easy to align.