Compact inductive sensors embedded in mould tools

When Carclo Technical Plastics recently won a major contract to supply speaker housings for a prestigious manufacturer of acoustic speakers for use in cars, it was soon established that, as part of the manufacturing process, there needed to be a check to establish that a connector terminal had been correctly positioned and moulded into each speaker housing.

This required a highly reliable, small and short-bodied device that could be flush-mounted into the mould tool itself. There followed a number of technical meetings between engineers at Carclo and Steve Gardner of Delta Automation Systems, an authorised Contrinex distributor and a company that Carclo relies on for technical support and supply of all sensor requirements. This study established that the most suitable sensor would be a Contrinex Sensor DW-AD-403-C5, a 4mm diameter embeddable inductive sensor with an operating distance of 0.8mm.

The Contrinex sensor was installed and rigorously tested in the aggressive conditions and high temperatures of the moulding process. The result was that the sensor worked extremely well over many cycles of operation and, because of the small detection zone, was able to verify that the electrical terminal was accurately aligned and positioned at the bottom of the tooling slot ready for moulding; a sensor with a larger sensing zone could not have achieved this with such accuracy and repeatability.

As a result of this success, this Contrinex S400 series inductive sensor, which is available in both 4mm and 3mm versions and is probably the smallest packaged sensor in the world, has been used on further applications at Carclo where it has been necessary to embed a sensor deep inside the tooling.