Cause analysis of warping deformation of injection molded products

1. Mold aspect:

(1) The thickness and quality of the parts should be uniform.
(2) The design of the cooling system should make the temperature of each part of the mold cavity uniform, and the pouring system should make the flow symmetry avoid the warpage caused by the different flow direction and shrinkage rate. It is difficult to properly thicken.
The shunting channel and the main flow channel of the molding part are as far as possible to eliminate the density difference, the pressure difference, and the temperature difference in the cavity.

(3) The transition zone and corner of the workpiece should be sufficiently rounded and have good demolding properties, such as increasing the demoulding margin and improving the polishing of the die face. The ejector system should be balanced.

(4) The exhaust should be good.

(5) Increase the wall thickness of the part or increase the direction of warping resistance, and strengthen the rib to enhance the anti-warping ability of the part.

(6) The strength of the material used in the mold is insufficient.
2. Plastics:

Crystalline type has more chance of warpage deformation than amorphous plastic, and crystallized plastic can be corrected by crystallizing process with crystallinity decreasing with increasing cooling rate and shrinking rate becoming smaller.

Warping deformation.

3. Processing:

(1) The injection pressure is too high. The three pressure regulating valves of the vertical injection molding machine are used. The holding time is too long. If the temperature of the melting material is too low, the internal stress will increase and the warping deformation will occur.

(2) The mold temperature is too high, and the cooling time is too short, so that the parts during demolding are overheated and the ejection deformation occurs.

(3) Reducing the screw rotation speed and the back pressure reduction density while maintaining the di-limit filling amount to limit the generation of internal stress.

(4) If necessary, the mold can be softly shaped or demoulded after the mold is easily warped and deformed.

youngstrong
Dongguan Taiwang Machinery Co.,LTD
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