Close this search box.
What are all the design guidelines required to develop a plastic part

What are all the design guidelines required to develop a plastic part?

Table of content

The following is a description of the key points of the plastic product structure design


The structural design of plastic product development should follow the following principles:

a. The structure design should be reasonable: the assembly gap is reasonable, and all plug-in structures should be reserved for gaps; ensure sufficient strength and rigidity (safety test), and properly design a reasonable safety factor.

b. The structural design of plastic parts should comprehensively consider the manufacturability of the mold, and simplify the manufacturing of the mold as much as possible.

c. The plasticity of the structure of plastic parts should be considered, that is, the injection molding production efficiency of the custom plastic injection molding companies should be high, and the rejection rate of injection molding should be minimized.

d.  Consider facilitating assembly production (especially not conflicting with assembly).

e. The structure of stamping plastic parts adopts standard and mature structure as much as possible, so-called modular design.

g. taking into account the cost


Points of Attention to Common Problems in the Design and Structure of Plastic Products


1. About the demoulding angle of plastic parts:

Generally speaking, for any side of the molded product, a certain amount of demolding slope is required to allow the product to be ejected from the mold smoothly. The size of the draft angle is generally between 0.5 degrees and 1 degree. You will get more details in advantages and disadvantages of compression moulding. Pay attention to the following points when selecting the draft angle:


2. About the wall thickness determination and wall thickness treatment of plastic parts:

It is very important to determine the wall thickness of plastic parts reasonably. The wall thickness of a plastic part is first determined by the use requirements of the plastic part: including the strength of the part, quality cost, electrical performance, dimensional stability, and assembly requirements. Generally, the wall thickness has an empirical value, which can be determined by referring to similar


3. Regarding the strengthening of plastic parts:

In order to ensure the strength and rigidity of the plastic part without causing the wall thickness of the plastic part to be too thick, reinforcement ribs can be set at the appropriate part of the plastic part. Reinforcing ribs can also avoid the deformation of plastic parts. In some cases, reinforcing ribs can also improve the flow of plastic during the molding process of plastic parts. Making the surface arched and waved is also one of the ways to increase strength and rigidity.


4. About the rounded corner design of plastic parts:

In the design process of plastic parts, in order to avoid stress concentration, increase the strength of plastic parts, improve the flow of plastic parts and facilitate demoulding, excessive arcs should be adopted on all sides or internal connections of plastic parts. In addition, the rounded corners on the plastic parts are also indispensable for mold manufacturing and machining, and to improve mold strength. When there are no special requirements on the structure of the plastic part, each corner of the plastic part should have a rounded corner with a radius of not less than 0.5~1mm. Where possible, the fillet should be as large as possible.

For the corners of the inner and outer surfaces, the outer fillet should be the inner fillet plus the wall thickness to reduce internal stress and ensure uniform wall thickness.