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Autoclavable overmoulding of electronics

Overmoulding of electrical connections

The lecture "How to seal the electrical connnection of your reprocessable electronic medical device" took place at MedtecLIVE on 21 April 2021.

Electronics for sterile applications

The use of electronics in medical technology is becoming more and more common, as is the trend towards miniaturisation. It is necessary to pack as many functions as possible into the smallest space in order to make the respective application as versatile and efficient as possible. In medical applications, hygienic protection and the prevention of moisture, humidity, bacterial contamination and other external factors are extremely important.

The autoclavable overmoulding not only protects the actual electronics, but the electrical connections, e.g. contact pins or cables, can also be integrated. This makes your product reusable and significantly reduces operating costs.

We optimise overmoulding for each product individually with respect to layout, components and the injection moulding tool. We primarily use thermoplastics, some of which are biocompatible, and also hot melt materials for specific applications. Overmoulding electronics can also take place in the clean room, if requested by the customer. There are various colours and translucent materials available. In addition to mastering the technical process, the choice of materials is also crucial.

An exampel of use how the technical possibilities of this procedure operate is our demonstrator Latooyete.

Materials are selected based on the following properties:

  • Selection of fillers according to the application (UV stabilisers, glass fibres etc.): This affects, for example, the thermal conductivity of the overmoulding material, which is also higher in standard materials than in stationary air
  • The thermal expansion coefficient is compatible with that of the electronics assembly
  • The viscosity of the material allows for overmoulding without pulling off components
  • The melting point is so low that the soldering paste does not liquefy
  • The material acts as a barrier against moisture, humidity and other undesired influences

Specific materials can survive hundreds of autoclaving cycles; no degradation of the material was observed during this period.  Resistance against cleaning agents and other liquids is very high. No accelerated aging has been observed.

By using suitable cables, it is possible to create sealed electronics assemblies (IP 68) that can also be autoclaved. Direct overmoulding makes it possible to manufacture cost-efficient and weight-optimised housings. Here, the housing with a minimum wall thickness of just 0.4 mm is built directly around the assembled PCB.

Don’t hesitate to get in touch with us to find the best material to protect your electronics.