What should I do if the injection mold malfunctions?
1、 Difficulty in material removal from the gate
In the process of injection molding production, due to the tendency of the sprue to get stuck in the sprue sleeve, cracks are less likely to occur, causing damage to the injection molded parts and seriously affecting production efficiency.
The reasons are as follows:
1. The smoothness of the sprue cone hole is poor, and there are knife marks in the circumferential direction of the inner hole;
2. The raw material of the injection mold is too soft, and after a period of use, the small end of the tapered hole deforms or is damaged;
3. The spherical curvature of the nozzle is too small, causing rivet joints in the gate material.
The solution is as follows:
1. The operator can use a copper rod to tap the nozzle of the injection mold to loosen it before demolding;
2. Due to the difficulty in machining the taper hole of the sprue sleeve, standard parts should be used for production as much as possible, or self machined by grinding the taper hole to Ra0.4 or above;
3. Set up a gate pull rod or gate ejection mechanism.
2、 Die guide post damage
The structure that plays a guiding role in the mold is the guide column, which ensures that the molding surfaces of the core and cavity do not come into contact with each other. It should be noted that the guide column is prone to damage and displacement during the processing.
The reasons for the problem are as follows:
1. The wall thickness parameter is uneven, and the flow rate of the material passing through the thick wall is high, resulting in significant pressure at this location;
2. The side of the plastic part is asymmetric, and the pressure on both sides is not equal.
The solution is as follows:
1. Guide pillars cannot be used as load-bearing or positioning components;
2. Standardize the manufacturing process of molds and design uniform and reasonable wall thickness parameters.
3、 Fixed and dynamic model offset
During the operation of injection molds, the fixed and moving molds may deviate, ultimately resulting in rough and damaged guide column surfaces. When the situation is severe, the guide post may bend or cut, and even the mold cannot be opened.
The reasons for the problem are as follows:
1. Different filling rates;
2. During mold installation, it is affected by the weight of the mold itself.
The solution is as follows:
1. Add high-strength positioning keys, such as cylindrical keys, on the parting surface of the mold;
2. Pay attention to the perpendicularity between the guide column hole and the parting surface. During processing, ensure the concentricity of the moving and fixed molds to reduce perpendicularity errors;
3. Ensure that the heat treatment hardness of the guide column and guide sleeve meets the design requirements.