Injection molding of polymers is a technological process of plastic processing by injecting a polymer melt under pressure into an injection mold with its subsequent cooling. The term – injection molding reflects a feature of the molding process, when significant melt pressures are used to compensate for volumetric and linear shrinkage during filling and cooling in a forming cavity (injection mold).
More than a third of the total volume of products from polymer materials is produced by injection molding. Due to the high productivity and relatively high cost of tooling, it is mainly used in large-scale and mass production of plastic products. Raw materials for casting are granules of thermoplastics, thermoplastic elastomers and thermosetting powders with a wide range of mechanical and physical properties. Thermoplastic materials remain recyclable after molding, while thermosetting materials undergo irreversible chemical changes during processing, leading to the formation of an infusible and insoluble material.
In the casting process, specially prepared material enters the auger zone of the machine, where it melts and homogenizes, and then under high pressure is injected into the mold through the gating channels, filling its cavity at a high speed, and then, cooling down, forms a casting. Curing of the material occurs first at the cold walls of the mold cavity, and then spreads deep into the body of the casting.
The following types of plastics are successfully used in production:
Engineering plastics
Polycarbonate (PC)
Polyacetal (POM)
Polybutylene terephthalate (PBT)
Polyamide (PA)
Polysulfone (PSU)
Polymethyl methacrylate (PMMA)
ABS – plastic (ABS)
Polycarbonate and ABS Blend (PC / ABS)
SAN – plastic (SAN)
Elastomers
Thermoplastic polyurethanes (TPU)
Thermoplastic Elastomers (TPE)
Polyurethane systems (PU)
Filler materials (glass, carbon, kevlar).
The plastic injection molding process allows the production of a variety of products with weights ranging from a few milligrams to 0.650 kilograms. Modern plastic molding allows you to create products of different thicknesses.
Plastic injection molding occurs under different pressure levels, most often 80-140 MPa. The increase in pressure may be due to the need to make products with increased strength. In addition, the increase in pressure allows for perfect adherence to the specified dimensions of the parts.
Before starting production, it is necessary to make (plastic) injection molds that match the future product to the smallest detail. (Plastic molds are cheaper, so the cost of working with this option is significantly reduced.)
How does a plastic injection molding machine work
In its work “TAGOR PLASTICS” uses the Japanese Fanuc injection molding machine. Its main advantages are high production speed and consistently high quality.This results in high acceleration, amazing motion precision and an unusually short cycle time. Additional benefits are optimized compression force and minimal defects.