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EspañolHow Injection Molding Gate Design Affects Part Quality in Plastic Injection Mold
All gate designs in injection molding force molten plastic under pressure into a cavity or core. So when the plastic goes into the plastic, they accelerate the plastic and add heat. The work of the gate can have several effects on the plastic part.
injection
A gate that is too small will cause a pressure drop as the molten plastic enters the cavity. As a result, it often leads to a defect called jetting. Jetting describes the injection of plastic into the core rather than the typical smooth flow. Such an event causes a wavy twist that manufacturers often refer to as a "worm". To overcome this problem, it is usually necessary to reduce the pressure or increase the gate size. Sometimes, you may need to do both.
overheat
Friction often occurs during high-speed injection of plastic through the gate. When the heat becomes too much, the resin can rot. This decay is usually the result of broken molecular bonds in the plastic.
However, excessive reduction or injection speed to avoid this decay may cause other molding defects such as weld lines. It can also lead to the poor mechanical strength of the final product. Additionally, slower cycle times often equate to fewer parts produced per hour. This in turn increases processing costs.
In this case, you can divide the volume of the plastic resin into several different gate traces. This way, you can distribute the pressure and avoid overheating in the process. You also have to be careful at this juncture. This is because multiple flow fronts often lead to air pockets and weld lines wherever the fronts meet in the cavity.
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