Molding Conditions of Injection Molding Machine (Part 3)

 1. Cooling time


The cooling time in injection molding conditions refers to the time required for the molded product to solidify in the mold. Switch to cooling time after holding pressure. The unit is s (second).


If the cooling time is too short, the amount of shrinkage will be large, the size of the product will be reduced, and deformation may occur during ejection.


On the other hand, if the cooling time is too long, the molding cycle will become longer and the productivity will decrease, that is, the processing cost of the molded product will increase. Cooling time is the most influential factor in the molding cycle, so how to shorten the cooling time is the key to shortening the molding cycle.


2. Measurement position


The metering position is the position where the screw or plunger measures the volume of resin required for injection molding. The unit is mm.


If the metering position is too short, poor filling will occur. If the metering position is too long, excess resin may remain in the barrel causing scorching or gas generation. The setting of the optimal metering position should take into account the injection volume of the molded product to ensure that the amount of resin measured each time is neither too little nor too much, but just right.


3. Speed-hold pressure switching position


refers to the screw position for switching between injection speed and holding pressure, and the unit is mm. The appearance or size of the molded product will change slightly due to this position change.


4. Screw advance position


This is the parameter that controls the final forward position of the screw after injection molding is completed. The unit is mm.


This is also a factor controlling the amount of buffering. The buffer amount refers to the molten plastic remaining in the barrel after the screw is fully pushed to the front end of the injection molding barrel. If the buffer amount is too small, the pressure holding may not work properly.


If there is too much cushioning, the material may become trapped and then deteriorate due to heat.

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