There are many forms of mold gates for the daily necess […]
There are many forms of mold gates for the daily necessities of automobile molds, but no matter what form of mold gate is used, its opening position has a great influence on the forming performance and forming quality of plastic parts. Therefore, the reasonable selection of the opening position of the mold gate is an important design link for the high quality of plastic parts. When selecting the gate location of the mold, factors such as the flow state of the molten plastic in the mold, filling conditions, and exhaust conditions should be analyzed according to the geometric characteristics and technical requirements of plastic manufacturing. The gate of the automobile mold should be opened at the thickest part of the plastic part. When the wall thickness of the plastic parts differs greatly if the gate of the mold is opened at the thin wall after the plastic melt enters the cavity, not only the flow resistance is large, but also it is easy to cool, which affects the flow distance of the melt, which is difficult to achieve. It is 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 at the thin wall, the surface depression or shrinkage cavity will be formed in the place where the wall thickness cannot be fed due to the shrinkage of the plastic melt.
The size and position of the gate of the automobile mold should be selected to avoid the phenomenon of jetting and creep. If a small mold gate is facing a cavity with large width and thickness, when the high-speed material flows through the gate, due to the high shear stress, melt fractures such as jetting and creeping will be produced. Sometimes the phenomenon of spraying can also cause corrugated flow marks to be formed on plastic parts.
The selection of the gate location of the mold should make the flow of the plastic the shortest and the direction of the material flow change the least.
The selection of the gate position of the mold should be conducive to the discharge of the gas in the cavity.
The material flow should prevent the cavity, core, and insert from being squeezed and deformed.