What Temperature is Required for Plastic in Injection Molding?
The temperature required for plastic in injection molding is a complex issue influenced by several factors, and there's no fixed value.
Key factors affecting plastic temperature include:
Type of plastic: Different plastics have different melting points and processing temperature ranges. For example, polyethylene generally requires a lower processing temperature than polystyrene.
Part wall thickness: Thicker parts require higher melt temperatures to ensure the melt can fully fill the mold.
Mold temperature: Mold temperature affects the cooling rate of the melt, which in turn influences the crystallinity and mechanical properties of the part.
The screw speed of the injection molding machine: Higher screw speeds generate more shear heat, which increases the melt temperature.
Part complexity: More complex parts have greater flow resistance, requiring higher melt temperatures.
Generally, the processing temperature range for plastics in injection molding is between 150°C and 350°C. The specific temperature needs to be determined based on the type of plastic, part design requirements, and the performance of the injection molding machine.
Methods to determine the plastic temperature:
Consult the datasheet: The property table provided by the plastic supplier usually gives the processing temperature range of the plastic.
Conduct trial molding: By conducting multiple trial moldings and observing the quality of the parts, gradually adjust the plastic temperature to find the optimal processing parameters.
Refer to experience: Experienced injection molding engineers can select the appropriate plastic temperature based on their experience.
