Which mistakes are easy to make in the process of injection molding?

In fact, injection mold engineering is often used to make plastic products, but also through a technology to make the structure and size of plastic into a workpiece, so the structure and quality of injection molding can directly affect the quality of finished products, so what are the problems in the injection mold work? Let's see.
1. Difficulty in gate stripping
In the process of injection molding, the gate gluing sleeve of the gate is easy to sag. When the mold is opened, cracks appear and the goods are damaged. In addition, operators have to use copper to knock from the nozzle head, which had a serious impact on production efficiency after the release. The main cause of this kind of failure is the difference of the end point of the taper hole and the circumferential direction of the hole mark. Secondly, the material is too soft, the small end of the taper hole is deformed or damaged after a period of time, and the spherical curvature of the nozzle is too small, which makes the rivet head produced here. The standard of machining difficulty should be adopted. For their own treatment, should be carried out later or special reamer. The polishing Ra of the cone is more than 0.4. In addition, the grid must provide a pull rod or sprue ejection mechanism.
2. The guide post is damaged
The guide post plays a guiding and educational role in the mold, so as to ensure that the forming surfaces of the core and the cavity can not touch each other in any case, and the guide post design can not be used as a force bearing part or positioning part. In the following analysis of several different cases, the dynamic mold will produce a huge lateral horizontal offset force during injection: (1) when the plastic part wall thickness requirements and uneven, the material flow through the thick wall speed is large, where we have a greater pressure; (2) the plastic part side reaction is not symmetrical, such as the development of the stepped parting surface, the opposite side of the mold structure is also not equal to the back pressure.
3. Bending of movable formwork
During injection molding, there may be reverse pressure in the cavity, and many workers often don't pay attention to this, which leads to the finished product out of expectation,
During injection, the molten plastic in the mold cavity produces a huge reverse pressure, generally 600-1000 kg / cm. Mold manufacturers sometimes do not pay attention to this problem, often change the original design size, or use low strength steel plate instead of moving template. Because of the large span on both sides of the valve seat, the mold plate will bend downward during injection molding.