The so-called injection molding means that the plastic materials in the barrel of the injection molding machine undergo external heating and the shear heat generated by the rotation of the screw to plastic the resin materials into a melt, and then through the application of a certain pressure, the melt is injected into the cavity with a certain shape. After cooling and shaping, the products produced are injection molding.
The process of injection molding can be roughly divided into eight stages: mold closing, seating, glue injection, pressure maintaining, melt+cooling, ejection, mold opening, and seating.
(Three basic elements of injection molding: machines - including injection molding machines, auxiliary machines, molds and materials)
Three elements of injection molding process:
1. Temperature:
A. Temperature: for the hydraulic press, it is the heat energy generated by the friction of the hydraulic oil during the non-stop operation of the machine. It is controlled by the cooling water. When starting up, make sure that the oil temperature is about 45 ℃. If the oil temperature is too high or too low, it will affect the pressure transmission.
B. Material temperature: refers to the temperature of the barrel. This temperature should be set according to the shape and function of materials and products. If there is a document, it should be set according to the document.
C. Mold temperature: This temperature is also an important parameter. Its height has a great impact on the performance of the product. Therefore, when setting, the function and structure of the product must be considered, as well as the material and cycle.
2. Pressure:
A. Glue injection pressure: according to the size of the product and the thickness of the wall, from low to high, other factors shall be considered during commissioning.
B. Pressure maintaining pressure: the pressure maintaining pressure is mainly used to ensure the shaping and size stability of the product, and its setting should also be based on the structure and shape of the product.
C. Low pressure protection pressure: This pressure is mainly used to protect the mold and minimize the damage to the mold.
D. Clamping force: It refers to the force required for the mold to close under high pressure. Some machines can adjust the clamping force, while others cannot.
3. Time:
A. Glue injection time: This time must be set longer than the actual time, which can also play the role of glue injection protection. The setting value of the injection time is about 0.2 seconds larger than the actual value. The matching with the pressure, speed and temperature should be considered when setting.
B. Low voltage protection time: under the manual state, first set the time to 2 seconds, and then add about 0.02 seconds according to the actual time.
C. Cooling time: This time is generally set according to the size and thickness of the product, but the glue melting time should not be greater than the cooling time, so that the product can be fully shaped.
D. Holding time: This time is the time for cooling the gate before the melt flows back under the holding pressure to ensure the product size after injection, which can be set according to the size of the gate.
