Mould Assembly Moment

  • Sep 27,2020
There are many types of plastic molds. Even if the same type of molds, due to the different types of plastics, the beginning and accuracy requirements are different, and the assembly methods are different.

Therefore, before assembling, we should carefully study and analyze the assembly drawing and parts drawing, understand the role, characteristics and technical requirements of each part, and determine the assembly benchmark. Through assembly, the final product quality indicators, mold action accuracy and various technical requirements in the use process are fully achieved.

1. Assembly Benchmarks

The assembly benchmarks can be roughly divided into:

The main working parts in the plastic mold such as core, cavity and insert are used as reference parts for assembly, and other parts of the mold have assembly reference parts for preparation and assembly.

Take the guide post and guide sleeve or the template side base surface of the mold as the assembly reference surface for trimming and assembly.

2. Mold Assembly Accuracy
The mutual accuracy of each part, such as distance dimensional accuracy, coaxiality, equality, perpendicularity, etc.
Relative motion accuracy, such as transmission accuracy, linear motion and rotary motion accuracy.
Fitting precision and contact precision, such as fitting clearance, interference contact condition, etc.
The wall thickness of the plastic molded part. When making a new mold, the wall thickness of the formed part should be biased to the lower limit of the size.

3. The Principle of Repair

To modify the demolding slope, in principle, the cavity should ensure that the size of the large end is within the tolerance of the part size, and the core should ensure that the size of the small end is within the tolerance of the part size.
The fillet radius at the corners, the cavity should be small, and the core should be large.

When the mold has both a horizontal parting surface and a vertical parting surface, the correction should be made so that when the vertical parting surface is in contact, there is a slight gap between the horizontal parting surface. Small molds only need to be painted red and touch each other, and the gap between large molds is about 0.02mm.

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