Plastic mold assembly points
There are many kinds of plastic molds with different ways of assembly methods .Even with a kind of mold, due to the different plastic material and different beginning and accuracy requirements, assembly methods are not the same too. Therefore,before assembling,we should analysis the whole assembly drawing including components drawings to know their roal,features and technical requirements.
Plastic injection moulds are variety. We have to know all the good methods to assemble them to make sure their precision of moving and all technical requirements when moulding.
1. The mounting Datum can be roughly divided into 1) Functional components in a plastic mould such as core, cavity and inserts to be assembly datum components, other parts of the mould will be assembled based on them as a datum (2) use guide pin guide bushing or mold plates’s side datum as assemble datum to mounting and revise the mould..
2. Mould mounting precision including: 1) the precision of each components such as the distance dimensional accuracy, concentricity, equality, vertical, etc. (2) the precision of the relative moving, such as transmission accurancy,and precision of linear moving and rotary moving accuracy. (3) Accurancy of coperation and touching like the coperation gap, the status of interference (4) the size of the wall thickness of the plastic molded parts. When making a mould, thickness of forming components should be close to the lower limit of the size.
3. repair Principle 1) repair angle draft, in principle,big end size of cavity should be within the top of tolerance. Ensure that small inner core carbonyl size. (2) radius of cavity round corner should be made smaller and radius of core round corner should be bigger (3) when mould both have horizontal parting line and vertical parting line, when we repair there should be a little gap between horizontal parting line and vertical parting line. (4) When closing mould with bevel surface, after close, there should be gap around 0.02-0.03mm (5) when repair, arc and straight line should be connected smoothly. Surface does not allow any dents; filing lines should be consistent with the direction of mold opening.