The working principle of engineering plastics processing mainly includes several main methods such as injection molding, extrusion molding, and blow molding.
Injection molding
Injection molding is to heat and melt plastic particles, inject them into the mold through an injection machine, and obtain the finished product after cooling and solidification. The specific steps include:
Raw material preparation: Put the dry plastic particles into the hopper of the injection molding machine.
Plasticization: The plastic particles are heated to a molten state in the barrel, and the screw rotates to push the plastic forward and stir and compress it to fully plasticize it.
Injection: The molten plastic is injected into the mold cavity at a certain pressure and speed under the push of the injection device.
Pressure holding: Apply pressure during the cooling process of the plastic to ensure the stability of the product size and surface quality.
Cooling: The mold is cooled through the water channel to completely solidify the plastic.
Mold opening and taking out: After cooling is completed, open the mold to take out the finished product.
Extrusion molding
Extrusion molding is to extrude the molten plastic through the mold into a continuous profile or film. The specific steps include:
Raw material preparation: dry plastic particles are placed in the hopper.
Melting: The plastic melts into a viscous melt in the heating chamber.
Extrusion: The melt is extruded through the outlet of the mold into the desired shape, such as film, sheet, pipe, etc.
Cooling: The extruded plastic product is cooled and shaped by the conveyor belt.
Blow molding
Blow molding is a method of making hollow plastic products. The specific steps include:
Raw material preparation: dry plastic particles are placed in the hopper of the extruder.
Melting: The plastic melts in the heating chamber.
Extrusion: The melt passes through the cavity of the mold to form a parison.
Inflation: The parison is inflated into a hollow product by gas pressure.