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Analysis on the main points of plastic mold assembly

update:15-01-2021
abstract:

There are many types of plastic molds. Even for the sam […]

There are many types of plastic molds. Even for the same type of mold, due to the different types of forming plastics, different beginning and accuracy requirements, and different assembly methods. Therefore, you should carefully study and analyze the assembly drawing before assembly. Parts diagrams, understand the role of each part, Features and technical requirements, determine the assembly benchmark. Through assembly, the final product quality indicators, mold action accuracy and various technical requirements during use are fully achieved.

1. Assembly base, assembly base can be roughly divided into

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

(2) Use the base surface of the guide pin guide sleeve or the template side of the mold as the assembly reference surface for trimming and assembly.

2. Mold assembly accuracy, mold assembly accuracy includes

(1) The mutual accuracy of each component and component, such as distance dimensional accuracy, coaxiality, equality, perpendicularity, etc.

(2) Relative motion accuracy, such as transmission accuracy, linear motion and rotary motion accuracy.

(3) Fitting accuracy and contact accuracy, such as fit clearance, interference contact condition, etc.

(4) The wall thickness of the plastic molded part. When the mold is newly made, the wall thickness of the molded part should be biased to the lower limit of the size.

3. Repair principle

(1) To modify the demolding slope, in principle, the cavity should ensure that the large end size is within the tolerance of the part size, and the core should ensure that the small carbonyl size is within the tolerance of the part size.

(2) The fillet radius at the corners, the cavity should be small, and the core should be large.

(3) 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. The gap value depends on mutual contact, and the gap between large molds is about It is about 0.02mm.

(4) For molds with inclined surfaces, after the inclined surfaces are closed, there should be a gap of 0.02-0.03mm at the parting surface.

(5) The arc and the straight line of the repair surface should be smooth, and the surface is not allowed to have dents, and the filing pattern should be consistent with the opening direction.