Effect of Wall Thickness of Plastic Parts on Quality of Injection Molding Products
The wall thickness of plastic parts processing has a great influence on the quality. If the wall thickness is too small, the flow resistance is large, and large-scale and complex plastic parts can hardly fill the cavity. The smaller size of the wall thickness of a plastic part should meet the following requirements:
1, has sufficient strength and stiffness;
2. It can withstand the impact and vibration of the demoulding mechanism when demoulding;
3, can withstand the fastening force when assembling.
Injection processing plants require smaller wall thickness values, which vary according to the type, grade, and product size of the plastic parts. Excessive wall thickness in the processing of plastic parts not only wastes raw materials, but also increases the molding time for the thermosetting plastics molding process, and can easily result in incomplete curing; while for thermoplastics, it increases the cooling time. In addition, the quality of plastic parts processing will also be affected. The wall thickness of the same injection molded part should be as uniform as possible. Otherwise, additional stress will be generated due to uneven cooling and solidification speeds.
|Plastic Material||Min Wall thickness (mm)||Small part wall thickness proposal (mm)||Middle size wall thickness proposal (mm)||Big part wall thickness proposal (mm)|
|PS||1||1.5||2 ~ 2.5||3 ~ 4|
|ABS||1||1.5||2 ~ 2.5||3 ~ 4|
|PP||0.8||1||2 ~ 2.5||2.5 ~ 3.5|
|PE||0.8||1||1.5 ~ 2.0||2.5 ~ 3.5|
|PC||1||1.8||1.5 ~ 3.0||3.0 ~ 4.5|
|PC/ABS||1||1.5||1.5 ~ 2.0||3 ~ 4|
|PMMA||1||1.5||2.0 ~ 3.0||4 ~ 6|
It is very important to determine the wall thickness of plastic parts reasonably. The wall thickness of plastic parts is determined firstly by the requirements for the use of plastic parts: including the strength, quality cost, electrical performance, dimensional stability, and assembly requirements of the parts. The general wall thickness has experience value, and the reference can be determined similarly (eg, The general wall thickness of the iron is 2mm, and the vacuum cleaner is generally 2.5mm). Note the following points:
a. The wall thickness of plastic parts should be as uniform as possible to avoid too thin, too thick and abrupt changes in wall thickness. If plastic parts require wall thickness changes, gradients or circular transitions should be used, otherwise the plastic parts will be deformed due to uneven shrinkage. , affecting the strength of plastic parts, affecting the injection molding fluidity and other molding process problems.
b, plastic wall thickness is generally in the range of 1-5mm. The more commonly used value is 2-3mm.
c. Smaller wall thickness and common wall thickness of commonly used plastic parts. Recommended value: (mm)
d, try not to strengthen the ribs and screw column design is too thick, it is generally recommended to take half the thickness of the body more insurance, otherwise it will easily lead to microcosm and other appearance problems
e. Try not to design the part as a separate plate. The size is small, otherwise the deformation will cause the part to be uneven.