There are many forms of gates for commodity molds, and the same is true for Crate Moulds. However, no matter what form of mold gate is used, its opening position has a great influence on the forming performance and quality of plastic parts. Therefore, a reasonable selection of the opening position of the mold gate is an important design link to improve the quality of plastic parts.
For Automotive moulds, when selecting mold gate positions, factors such as the flow state of 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 mold gate 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, affecting 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 form a surface depression or shrinkage due to the shrinkage of the plastic melt.
The size and position of the mold gate should be selected to avoid jetting and creeping. If a small mold gate is facing a cavity with a large width and thickness, when the high-speed material flows through the gate, due to high shear stress, it will produce melt fracture phenomena such as jetting and creeping. Sometimes the spray phenomenon will cause the plastic parts to form corrugated flow marks.
The location of the mold gate should be selected to make the plastic flow the shortest and the direction of material flow change the least.
The selection of the gate position of the mold should facilitate the discharge of gas in the cavity.
The material flow should prevent the cavity, core and insert from squeezing and deforming.