There are many forms of mold gates for daily necessities, but no matter what type of mold gate is used, the location of its opening has a great influence on the forming performance and forming quality of plastic parts. Therefore, the reasonable choice of the location of the mold gate is an important design link to improve the quality of plastic parts. When selecting the location of the mold gate, the flow characteristics of the molten plastic in the mold, the filling conditions and the exhaust conditions should be analyzed according to the geometric characteristics and technical requirements of the plastic manufacturing. The mold gate should be opened at the thickest section of the plastic part. When the wall thickness of the plastic parts differs greatly, if the mold gate is opened at the thin wall, this is not only a large flow resistance after the plastic melt enters the cavity, but also easy to cool, affecting the flow distance of the melt, difficult Easy to ensure that the entire cavity is filled. The wall thickness of the plastic part is often the place where the melt solidifies at the latest. If the gate is opened in the thin wall, the wall thickness will form a surface depression or shrinkage hole due to the shrinkage of the plastic melt.
The size and location of the mold gate should be selected to avoid spraying and creeping. If a small mold gate is facing a cavity with a large width and thickness, when the high-speed stream passes through the gate, due to high shear stress, melt fracture phenomena such as spray and creep will be produced. Sometimes the spraying phenomenon will cause the plastic parts to form corrugated flow marks.
The location of the mold gate should be selected so that the plastic flow is the shortest and the direction of the material flow is the least.
The choice of mold gate location should be conducive to the exhaust of gas in the cavity.
The material flow should be prevented from squeezing and deforming the cavity, core, and insert.