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Name:Rebecca Dong
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Cause analysis of product cracking during processing of injection molding parts. |
1. Processing:
(1) excessive processing pressure, too fast speed, more filling, injection and overpressure time will cause excessive internal stress and cracking.
(2) adjust the opening speed and pressure to prevent the fast and strong drawing parts from cracking.
(3) adjust the mold temperature appropriately so that the making parts are easy to mold, and properly lower the material temperature to prevent decomposition.
(4) the cracking occurs when the mechanical strength is reduced due to the melting of the welding mark.
(5) use the release agent properly, and pay attention to the air fog and other substances that often remove the mold surface.
(6) the residual stress of the parts can be eliminated by annealing heat treatment immediately after forming to reduce the generation of cracks.
2. Mold aspects:
(1) balance the top out, such as the number of the top bar, the area to be cut, and the Angle of the mould should be enough, so that the cavity surface should be smooth enough, so as to prevent the cracking of the residual stress concentration due to external forces.
(2) the manufacturing structure should not be too thin, and the transition part should be used as an arc to avoid the stress concentration caused by sharp corners and chamfer.
(3) minimize the use of metal inlays to prevent the increase of internal stress due to different shrinkage rate of embedded parts and parts.
(4) a suitable stripping inlet channel should be set for deep bottom parts to prevent vacuum negative pressure.
(5) the mainstream channel is enough to remove the mold before the gate is cured, which is easy to remove.
(6) the main channel liner and nozzle joint shall prevent the drag of the cold hard material and make the parts stick to the mold.
3. Materials:
(1) the raw material content is too high, resulting in too low manufacturing strength.
(2) the humidity is too large, causing some plastics to react with water vapor, reducing the strength and cracking.
(3) the material itself is not suitable for the processing environment or poor quality, and the pollution will cause cracking.
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Down:The shell of injection molding is a lot of, which injection molding shell need dustproof, waterproof? Up:Three conditions that must be noted in the process of injection molding. |
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