Carbon black used in wireless test

ERJ staff report (PRW)

Datchet, UK -- IDC Models has used a very high density of carbon black in a model of a hand, designed to test energy absorption from mobile phones. The project was developed for IndexSAR, specialists in performance-testing wireless systems.

IndexSAR asked IDC Models to find a solution to a difficult moulding issue. IndexSAR required a model of a human hand which would incorporate carbon black to absorb the radio waves emitted by mobile phones on test, but this presented several problems.

Vince O'Horo, director of IDC Models, said: “Carbon black is a difficult substance to work with. The ratio of carbon to polymer needed to be exactly right in order to distribute the carbon evenly throughout the phantom hand. Often the carbon powder becomes very thick when mixed, making it difficult to manipulate and creating air pockets within the mould. We had to work quickly and accurately, employing a moulding technique customised for this particular job.”

Rapid prototyping played a key part in perfecting the production process in-house at IDC Models. Polyurethene elastomer was used to allow the “phantom” fingers to flex and curve around a mobile phone for testing, regardless of its shape or size.

Engineers and model-makers worked together to devise a specialist moulding technique which solved the problems raised by the materials and the design of the system itself. After producing numerous prototypes, the model-making team found that a moulding system which encompassed half pressure casting and half vacuum-casting was the most effective and efficient.

O'Horo continued: “Having an in-house stereolithography machine to produce durable master three-dimensional parts from which to make the moulds reduced lead times. Perfecting our process has obviated the possibility of wasted, imperfect models, allowing the client to supply demand quickly and effectively.”

IDC Models has produced more than 20 phantom hand models for Indexsar in a variety of sizes to meet the demands of the mobile phone design. Each model has been produced using the customised technique.

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Plastics & Rubber Weekly (a Crain publication)

Press release from IDC models