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Over-injection. Metallic parts with over-injected plastic materials

At OSF we have extensive experience in over-injection for different applications.

Over-injection is a material combination technology, with which a metal part can be covered with thermoplastic material, elastomer, thermosetting material or liquid silicone/LSR.

The aim of this technology is:

  • Obtain plastic parts with greater resistance, as the inside of the parts is rigid.
  • Avoid breakage or tearing of flexible parts (made of elastomers) that are to be assembled.
  • Avoid friction noises in metal parts.
  • To avoid wear and/or heating of metal parts.

In order to achieve the overinjection of metal-plastic parts, it is essential to know the materials and the technology and process and thus be able to find the right way to join the two materials.

It is also necessary to have experience in the manufacture of moulds for overinjection.

A correct design of the moulds is important to avoid problems of detachment or breakage of the materials. It is also important to avoid burrs on the parts that can affect the performance.

Some of the parts we have developed and manufactured at OSF for our customers are for example:

  • Part made of thermoplastic material with metal inserts to be able to thread parts.
  • Thermoplastic part with a metal tube inside.
  • Friction-resistant thermoplastic part with a metal interior to withstand movement and prevent breakage.
  • Elastomer material gasket with metal inserts, to position it in the engine compartment, preventing the part from breaking or tearing when in contact with the positioners.
  • Medium-sized metal part in which thermoplastic is over-injected in some areas of the part to prevent noise due to friction.

At OSF we study each project to provide the solution to our customers' needs, contributing our technology and experience.