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Injection molding

KERN-LIEBERS – Your specialist for plastic composite parts. We overmold stamped strips and loose inserts.

Insert technology

Metal parts are inserted into an injection mold and overmolded with plastic. The parts used here are mainly coated stamped strips (conductor rails) and bushings, but other inserts such as resistors and Hall sensors can also be inserted and coated in plastic.

Outsert technology

Plastic elements are sprayed on a metal support and anchored using undercut and apertures.

Benefits of the technology

  • Simplified production of multi-functional components
  • Minimized manufacturing tolerances through increased precision and reproducibility
  • Operations for post-processing can be omitted
  • Reduction in the number of parts used
  • Cost savings through reduced component use
  • Processing of different components in a single operation
  • Elimination of small-scale assembly processes possible

Single-component injection molding is used to manufacture simple to complex components made of one plastic component. In everyday language, these are often called free-falling parts, because they are often simply sent as bulk goods without any further processing.

In multiple-component injection molding, the components are made of at least two plastic components in a single injection molding process. Among the most widespread of these are compounds of thermoplastics and thermoplastic elastomers, used to create sealing geometries or vibration dampers. However, applications with light-conducting materials in combination with materials for the manufacture of supports for these components are also possible.

The reel-to-reel overmolding process enables the cost-effective manufacture of mass production parts. Here, specially manufactured and coated stamped strips are introduced into an injection mold in a concatenated process. While remaining on the belt, the stamped parts are first coated with plastic and then finished using bending tools. The molded parts on the belt can now be processed as one of three variants:

  • Bulk goods: Here, the parts are separated out in the last operation and packaged as free-falling parts in polybags.
  • Set goods: Here, the parts are separated out in the last operation, removed from the tool by a handling system and packaged in trays or blister.
  • Coil goods: This is the original idea of the reel-to-reel process. Instead of the parts being separated out from the belt at the end of the process, they are wound onto a coil and delivered to the customer for further processing. The final separation process is then the first process step carried out by the customer.

This manufacturing process is used mainly to manufacture flat connectors for automotive applications and components for telecommunication products.

Industry applications


Electrical engineering

Building services engineering

Consumer goods

Mechanical engineering and equipment manufacturing

Medical technology