Guide column damage

The guide post mainly plays a guiding role in the mold to ensure that the molding surfaces of the core and the cavity do not touch each other under any circumstances, and the guide post cannot be used as the force receiving member or the positioning member. In the following cases, when the injection is moving, the fixed mold will produce a large lateral offset force: (1) When the wall thickness of the plastic part is not uniform, the flow rate through the thick wall is large, where it is produced. Large pressure; (2). The side of the plastic part is asymmetrical, such as the back pressure of the opposite sides of the mold of the stepped parting surface is not equal.

Large mold

Due to the different filling rates and the influence of the mold's own weight during the mold loading, the dynamic and fixed mode offsets are generated. In the above cases, the lateral offset force will be applied to the guide post during injection. When the mold is opened, the surface of the guide post is pulled, damaged, and the guide post is bent or cut in severe cases, and even the mold cannot be opened.

In order to solve the above problems, a high-strength positioning key is added on each side of the mold parting surface, and the most convenient and effective one is to use a cylindrical key. The verticality of the guide post hole and the parting surface is very important. When the machining is carried out, the fixed mold is clamped at the position and clamped once on the trampoline, thus ensuring the concentricity of the moving and fixed hole, and Minimize the verticality error. In addition, the heat treatment hardness of the guide post and the guide sleeve must meet the design requirements.