During the Crate Mould(FURNITUREMOULD) process, the plastic in the gate sticks into the sprue bushing and is not easily removed. When the mould is opened, cracks are broken in the plastic product. In addition, the operator pulls out the entire hot runner with a ejector, and then repairs the runner and illuminates it. If it continues, it will seriously affect production efficiency.
The reasons for these problems are: the smoothness of the taper hole is not enough, the inner hole has the knife mark not polished, the second is that the material is too soft, the small end of the tapered hole is deformed or damaged after a period of use, and the spherical curvature of the nozzle is too small, resulting in the gate material A rivet head is produced here. The taper hole of the sprue sleeve is difficult to process. Standard parts should be used as much as possible. If you need to process it yourself, you should also make a special reamer. The taper hole needs to be ground to Ra0.4 or higher; in addition, the gate pull rod or the gate ejecting mechanism must be provided.
2. It is difficult to remove the gate
Large-scale crate mould have different moving and fixed-mode offsets due to different filling rates and the influence of the mould's own weight during mould loading. In the above cases, the lateral offset force will be applied to the guide post during injection. When the mould is opened, the surface of the guide post is pulled and damaged. In severe cases, the guide post is bent or cut, and even the mould cannot be opened.
In order to solve the above problems, a high-strength positioning key is added on the parting surface of the crate mould, and one of the four sides is used. The most convenient and effective one is to use a cylindrical key. The perpendicularity of the guide post hole to the parting surface is critical. During processing, after clamping with the movable and fixed mould alignment positions, the boring is completed once on the trampoline, which ensures the concentricity of the moving and fixed hole and minimizes the vertical error. In addition, the heat treatment hardness of the guide post and the guide sleeve must meet the design requirements.