The gate is a short groove with small cross section area, which is used to connect the runner and the mold hole. The cross section area should be small in order to achieve the following effects:

Injection molding is a method for the production of industrial products. Products usually use rubber injection molding and plastic injection molding. Injection molding can also be divided into injection molding molding and die casting method.



Injection molding machine (referred to as injection machine or injection molding machine) is the main molding equipment that makes thermoplastic or thermosetting materials into plastic products of various shapes using plastic molding molds. Injection molding is achieved by injection molding machines and molds.

Polybutylene terephthalate (PBT) has excellent comprehensive properties, such as high crystallinity, rapid prototyping, weather resistance, low friction coefficient, high thermal deformation temperature, good electrical properties, excellent mechanical properties, fatigue resistance, ultrasonic welding and so on. However, its notched impact strength is low, the forming shrinkage rate is large, the hydrolysis resistance is poor, and it is easy to be eroded by halogenated hydrocarbons. After glass fiber reinforcement, the product is easily warped due to the inconsistency of the longitudinal and horizontal shrinkage rates.

The injection mold is made of tool steel. In the work, it encounters corrosive gases, water and other substances that cause rust. The plastic parts made from rusty molds will have quality problems, so they need to be eliminated.

The so-called exposed fiber is the glass fiber exposed on the surface of the product, relatively rough, the appearance is more difficult to accept, the possible causes of analysis: When adding this kind of filler, the physical mixing method is generally used, so only the glass fiber is evenly dispersed in the middle of the plastic, but after the plastic melts, the mixture will have different degrees of separation (depending on the proportion of the added and the length of the glass fiber, and the temperature of the raw material also has a certain degree of influence).

When the molten plastic meets the insert, the hole, the flow rate is not coherent, the area where the flow of the filling material is interrupted in the mold cavity, and when the pouring gate jet filling occurs, the linear fusion mark is produced because it cannot be completely fused. The existence of weld marks greatly weakens the mechanical strength of the product. The method of overcoming the weld mark is basically the same as that of reducing the dent of the product.

The basis for setting the speed segment must take into account the mold geometry, other flow constraints and instability factors. The speed setting must have a clear understanding of the injection molding process and material knowledge, otherwise, the product quality will be difficult to control. Because the melt flow rate is difficult to measure directly, it can be calculated indirectly by measuring the screw forward speed, or the cavity pressure (to determine that the check valve does not leak).

The polishing in the plastic mold processing is very different from the surface polishing required in other industries, and strictly speaking, the polishing of the mold should be called mirror processing. It not only has high requirements for polishing itself but also has high standards for surface smoothness, smoothness and geometric accuracy. Surface polishing generally requires only a bright surface.