Five main factors of injection molding process

2025-04-23

The five main factors of the injection molding process are: temperature, speed, pressure, time and position.

1. Temperature can be divided into three types: the first is oil temperature, the second is material temperature, and the third is mold temperature. The increase in oil temperature is due to the friction heat generated during the continuous operation of the hydraulic press, which causes the hydraulic oil temperature to rise. It is regulated by cooling water. When starting the machine, it is necessary to confirm that the oil temperature is about 45 degrees Celsius. Too high or too low oil temperature will affect the pressure transmission effect. Material temperature is a molding temperature of the raw material. The temperature of the barrel is set according to the material and the shape of the product.

(Plastic injection temperature)

2. Speed refers to the speed setting of mold opening and closing. The settings of mold opening and closing are generally one slow, two fast, and three slow. This setting is mainly to protect the mold and the machine. Two fast can improve the molding cycle of our products. A parameter setting of the ejector is set according to the structure of the mold and the product. If the product is ejected with a bag or white, it is recommended to slow down the speed and then demold quickly. It can shorten our molding cycle. The injection speed is set according to the size of the product. If it is a thin-walled product, use fast speed, and if it is a thick-walled product, use slow speed. The specific setting depends on the performance of the material, from slow to fast.

Injection mold

(Injection mold)

3.The injection pressure is set from low to high according to the size of the product and the thickness of the wall to achieve the appropriate parameters. The holding pressure is mainly to ensure the qualitative properties of the product and then stabilize the size. It is set according to the structure of the product. The low-pressure protection pressure is mainly a protection for the mold to minimize the damage to the mold. The clamping force refers to the force required for high pressure when the mold is closed. Some robots can adjust the clamping force, while some robots cannot adjust the clamping force manually.

(Plastic injection)

4. Injection time: This time is longer than the actual time, which can play a protective role in injection. When setting, the set value is about 0.2 seconds larger than the actual value. When setting, consider whether the pressure, speed and temperature match, and the low-pressure protection time. This time can be set to 2 seconds in manual mode first, and then add to the input cooling time of about 0.02 seconds according to the actual time. This time is set according to the size and thickness of the product, but the sol time should not be greater than the cooling time to achieve product finalization. The holding time is the time to cool the glue port before the container flows back under the holding pressure after the injection molding is completed in order to ensure the size of the product. It can be set according to the size of the glue port.

(Plastic injection time)

5. Position: The position of mold opening and closing is set according to the speed of mold opening and closing. The key is to set the starting position of low-pressure protection. The starting position of low pressure should be the most likely to protect the mold without affecting the middle finger position of a cycle. Because when the mold is closed at a slow speed, the position where the dynamic mold contacts the static mold, the ejector position, this position can satisfy the complete demoulding of the product. First, it is a process from short to long. Note that the retraction position must be set to 0 when the mold is in the middle, otherwise the mold will be damaged. The sol position is calculated according to the size of the product and the size of the screw to calculate a material measurement and set the corresponding position.