MID technology: Highly integrated components with potential for the future

Articel of 27 March 2015 

Moulded Interconnect Device technology is also used for the BionicANTs

With the help of Moulded Interconnect Device technology – MID for short – visible, three-dimensional circuit traces can be applied on the surface of injection moulded components. This enables mechanical and electronic functions to be integrated on a single moulded part in a unique way.

The products can therefore be designed much more freely in terms of space and made much smaller and lighter – an important step towards further miniaturisation. At the same time, MID components often make do completely without cables, which makes them much easier to assemble.

Injection moulded shaped parts with structured circuit pattern

Unlike classic, predominantly two-dimensional printed circuit boards, MID technology uses a three-dimensional shaped part as a circuit board – for example the housing. There are various production methods for making MIDs. In the case of the frequently used Laser Direct Structuring (LDS), a special metal connection is added to the injection moulding plastic.

The required component is first moulded from this material. The areas where circuit traces are planned are then exposed with a laser beam. At the same time the added metal connection is activated and can be immersed in a copper bath, for example, during the subsequent metallisation process, whereby the circuit traces are formed with a sharp outline. Various coatings made of copper, nickel or gold can thus be applied one after the other. Electric circuits can be soldered onto the resulting conductive areas.

Laser processing of circuit boards and printed circuit boards (photo credit: LPKF/LDS)
Laser processing of circuit boards and printed circuit boards (photo credit: LPKF/LDS)

BionicANTs – MID technology in miniature ant robot

For Festo, 3D MID technology offers great potential for the future of automation technology and use in future production systems. With the BionicANTs, Festo has produced miniature robots for the first time based on this technology. The bionic technology platform is inspired by the natural role model of an ant. It demonstrates how units can work efficiently together by means of autonomous decision-making and cooperative behaviour.

Thanks to 3D MID technology, all the mechanical and electronic functions were able to be housed on the ant measuring just 13.5 cm and exactly coordinated – functional integration in its complete form!

Numerous components, technologies and functions are combined in each ant in the smallest of spaces
Numerous components, technologies and functions are combined in each ant in the smallest of spaces

MID used in practice

The small dimensioned MID technology has already proven itself in many everyday applications. MIDs can be found in cars, for example: in the ESP brake control system, a compact MID pressure sensor converts the hydraulic braking pressure into an electrical signal. MIDs are also used in mobile telephones. Here, the three-dimensional circuit boards on the plastic housing inside the mobile phone act as an integrated antenna. Applications can also be found in medical, air conditioning and safety technology, among others.