Two-part process produces soft-touch hard case

Two different materials were used in constructing the case for a novel handheld gas monitor: a tough plastic substrate and a softer rubberised material for a comfortable touch.

Two different materials were used in constructing the case for a novel handheld gas monitor, a substrate of tough plastic to hold firm the PCB and components and a softer rubberised material for a comfortable touch.

Normally two-part/colour moulding using the same machine means complex expensive tools but using two tools Toolcraft Plastics of Swindon provided cost benefits and other advantages.

For example parts inspection between the shots improves overall yield as defective pieces were eliminated at the first stage.

Careful choice of material and controlled conditions, particularly on the second mould ensured a firm bond without parts distortion.

The monitor, which detects hydrogen sulphide, carbon monoxide and carbon dioxide, has visible and audible alarm.

To complete the assembly, Toolcraft manufactured two translucent covers, one of which incorporated a clear lens and in the same operation ultrasonically welded threaded brass inserts into the chassis, before pad printing onto it.

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