The structure of Furniture Mould and the process of mould processing will affect the quality of plastic parts. Sometimes, furniture moulds also show defects in production, so how do we eliminate our needs?
1. Damage of guide pillar.
The guide pillar plays a leading role in the furniture mould to ensure that the moulding surfaces of the core and the cavity do not collide with each other under any circumstances. The guide pillar cannot be used as a force bearing member or a positioning member. Under the following conditions, the fixed mould will have huge lateral deflection force when moving during injection:
(1) When the wall thickness of the plastic parts is not uniform, the flow rate through the thick wall is large, and a large pressure occurs here;
(2) The side of the plastic part is asymmetric, such as the mould with stepped parting surface, and the opposite side faces are not subjected to equal backpressure.
2. Moving and fixed die offset.
Large furniture moulds have different filling rates in different directions and are subject to deadweight during filling, thus moving and fixing the moulds are deviated. In the above cases, the lateral deflection force will be applied to the guide pillar during injection, and the outer surface of the guide pillar will be roughened and damaged during mould opening. In severe cases, the guide pillar will be twisted or cut off, or even unable to open the mould. In order to deal with the above problems, a high-strength positioning key is added on the parting surface of the furniture mould, one on each side, and a cylindrical key is simply and effectively selected. The straightness of the guide post hole and parting surface is very important. During processing, the movable and fixed dies are selected to be aligned and clamped and then bored on the boring machine at one time, thus ensuring the concentricity of the movable and fixed die holes and minimizing the straightness error. In addition, the heat treatment hardness of the guide pillar and guide sleeve must meet the planning requirements.
3. The gate is difficult to take off.
In the process of injection molding, the gate is stuck in the gate sleeve and is not easy to come out. When the mold is opened, the product shows crack damage. In addition, it is necessary for the operator to knock out the top copper bar from the nozzle to loosen it before demoulding, which severely affects the production power. The main reason for this problem is the poor finish of the gate taper hole and the knife marks in the circumferential direction of the inner hole. Secondly, the material is too soft, the small end of the cone hole is deformed or damaged after being used for a period of time, and the radian of the spherical surface of the nozzle is too small, resulting in riveting of the gate material here. It is difficult to machine the taper hole of the sprue bushing. Standard parts should be selected as far as possible. If self-machining is required, self-discipline or purchasing a special reamer should also be adopted. Taper holes shall be ground to Ra above Ra0.4. In addition, it is necessary to set the gate pulling rod or gate ejection organization.
