What are the types of gates for commodity molds?

2021-03-23 18:23:07 admin

What are the types of gates for commodity molds?

There are many forms of mold gates for 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 molding quality of plastic parts. Therefore, a 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 position of the mold, it is necessary to analyze the flow state of the molten plastic in the mold, the filling conditions and the exhaust conditions according to the geometric characteristics and technical requirements of the plastic manufacturing. The gate of the automobile mold mold should be set at the thickest part of the plastic part. When the wall thickness of the plastic part differs greatly, if the mold gate is opened in the thin wall, it is difficult for the plastic melt to flow into the cavity, not only the flow resistance is large, but also easy to cool, which affects the flow distance of the melt. 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 is the last to solidify. If the gate is opened in the thin wall, the wall thickness will not be fed due to the shrinkage of the plastic melt, and surface depressions or shrinkage holes will be formed.

The size and position of the gate of the automobile mold should be selected to avoid the phenomenon of jetting and creeping. If the small mold gate is facing a cavity with a large width and thickness, when the high-speed material flows through the gate, it will be subjected to high shear stress, which will produce melt fracture phenomena such as jetting and creeping. Sometimes the spray phenomenon will also 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 material flow changes the least.

The selection of the gate position of the mold should be conducive to the discharge of gas in the cavity.

It is necessary to prevent the material flow from squeezing and deforming the cavity, core and insert.