According to the cause of air bubbles or vacuum voids , the solutions to the defects are described as below: (1) When the wall thickness of the product is large, the outer surface is cooled down faster than the center portion. Therefore, as the cooling progresses, the resin at the center portion is expanded toward … Read more
The defects in the injection molding of acrylic PMMA usually include: short shot, silver streaks, sink marks, voids, jetting, weld marks, gray / black specks, cracking, warpage, and material impurity, while the preventive measures against them are usually: Short Shot This is caused because the resin does not fill the cavity fully. To prevent its … Read more
The setting of hold pressure is aimed to prevent resin backflow, while at the same time compensating for resin shrinkage caused during the cooling process, so as to achieve the optimal molding outcome. If the holding pressure is set too high, the product will be prone to flash, over filling or stress concentrating near the … Read more
By virtue of its enormous benefits, such as light weight, outstanding toughness, easy molding and low cost, plastic is gaining more and more popularity in modern industry and the production of daily necessities, because it is an ideal substitute for glass. Especially, in the fields of optical devices and the packaging industry, it has witnessed … Read more
The causes and countermeasures described below are aimed to solve the commonly seen injection molding defects that might occur in ordinary circumstances. The examples are just based on my own personal work experience, so if there is anything inappropriate, you are welcome to correct me! Short shots (incomplete filling) (1) Short shots (incomplete filling): The … Read more