Injection molding of plastic parts

Injection molding of plastic parts

Gestión de Compras have the means to get the parts manufactured by injection molding a wide variety of polymers and sizes.

Process of injection molding

Basically, injecting plastic parts consist in that granular plastic is fed by gravity from a hopper into a heated barrel. As the granules are moved forward by a screw-type plunger, the plastic is forced into a heating chamber, where it is melted. As the plunger advances further, the melted plastic is forced through a nozzle into the mold cavity. The mold remains relatively cold so the plastic solidifies almost as soon as the mold is filled.

This process has six stages:

  1. Vacuum mold closure.
  2. Inject the material, forcing it to pass from the nozzle to the mold.
  3. Solidifying the material, with the support of die pressure.
  4. Lamination of the material.
  5. Cooling the material inside the mold, thanks to the refrigerant.
  6. Removing the piece. Restart the cycle.



Gestión de Compras have the means to get the parts manufactured by injection molding a wide variety of polymers and sizes. We design, develop and manufacture injection plastic parts according to customer necessities.

Materials and products

Most polymers may be used for injection parts, including all thermoplastics, some thermosets and some elastomers. There are tens of thousands of different materials available for injecting pieces and that number is increasing every year.

Some examples of the material commonly molded are: Nylon, Acetal, Polycarbonate, Polystyrene, Acrylic, Polytetrafluoroethylene (PTFE), Acrylonitrile butadiene styrene (ABS), Polyvinyl chloride (PVC), Fibre-reinforced plastics.

There is a huge range of plastic parts made by injection such as electronic housings, containers, bottle caps, tops, lids, automotive interiors, motorcycle parts, automotive parts, robot parts, combs, toys, medical instruments, biomedical packaging, promotional and advertising products, domestic appliances parts, office accessories, knobs, industrial tools, power tool components, valves and most other plastic products available today.



Dimensional tolerances for an injection moulded part are determined by how well material shrinkage is predicted. For this reason is very important to know final product material before the mould is dimensioned.

Standard and certificates


Our factories have the most demanding certifications for customers to ensure product quality as:

  • ISO 9001 y ISO 14001.
  • TS 16949.
  • ISO 8062, ISO 286-2, DIN 2768, DIN 1697, UNE-EN ISO 14405, etc.
  • OHSAS 18001.
  • ISO 294, ISO 1268, ISO 13586, etc.