The phenomenon of bubbles in PC plastic injection molding process is very serious. Problems that should be paid attention to in Dalian injection molding mold design (including product design) in order to prevent poor plastic molding, surface defects and deterioration caused by poor reflux or uneven cooling, the following points should be paid attention to in mold design:
A = the wall thickness shall be as uniform as possible, and the demoulding slope shall be large enough;
B = the transition part shall transition gradually and smoothly to prevent sharp corners. Sharp edges, especially PC products, must not have gaps;
C = gate. The runner shall be as wide and short as possible, and the gate position shall be set according to the shrinkage and condensation process, and the cold charging well shall be added if necessary;
D = the die surface shall be smooth and low roughness (preferably less than 0.8); E = vent. The tank must be sufficient to discharge air and gas in the melt in time; F = except pet, the wall thickness shall not be too thin, generally not less than LMM.
The preparation and drying of the material may affect the transparency of the product due to any impurity in the plastic, so it is difficult to store and transport. During feeding, attention must be paid to sealing to ensure that the raw materials are clean. In particular, the raw materials contain water, which will cause the deterioration of the raw materials after heating, so they must be dried, and the drying hopper must be used for feeding during injection molding.
It should also be noted that during the drying process, the input air should be filtered and dehumidified to ensure that it will not pollute the raw materials. For example, the drying process of transparent plastics: material process drying temperature (℃) drying time (H) material layer thickness (mm) remarks pmma70 ~ 802 ~ 430 ~ 40pc120 ~ 130 > 6 < 30. It is better to use hot air circulation drying pet140 ~ 1803 ~ 4 and continuous drying feeding device.
Dalian injection molding
