1. Cooling Time

The cooling time in plastic injection molding is the period of time over which the molded article is left in the mold to solidify. The cooling time starts when the dwell time ends. The unit is s (seconds).

If the cooling time is too short, the shrinkage becomes high making the dimensions small, and the molded article may also get deformed during its ejection from the mold.

On the other had, if the cooling time is too long, the molding cycle becomes longer reducing the productivity. In other words, the cost of producing a molded article increases. Since the cooling time is a factor having the highest effect among all the factors affecting the molding cycle time, shortening the cooling time becomes a very important key to shortening the molding cycle time.

2. Measuring Position

The measuring position is the position of the screw or plunger for measuring the volume of plastic necessary for injection. The unit is mm.

Fill defects will occur if the measuring position is too short. If the measuring position is too long, excess plastic will remain in the cylinder causing burning, or generating gas. The measuring position should be set to the appropriate value considering the shot volume required for the molded item so that it is neither too small nor too large.

3. Speed - Dwell Swictchover Position

This is the screw position for switching between the injection speed and dwell, and its unit is mm. When this position is changed, there will be fine changes in the external appearance and the dimensions of the molded article.

4. Screw Forward Position

This is the parameter that controls the position to which the screw advances to the most forward position after injection is completed. Its unit is mm.

This is also a factor that controls the amount of cushion. The amount of cushion is the molten plastic remaining inside the cylinder at the tip of the screw after the screw has moved to the most forward position. If the amount of cushion is small, the dwell pressure will not act properly.

If the amount of cushion is too much, the material remains and gets the effect of heat thereby deteriorating.