Novel sensor system measures thickness of wet paint coatings

Novel sensor system measures thickness of wet paint coatings and tyres

An innovative combination sensor system has been developed, which attaches directly to a robot arm, so that automotive OEMs can inspect the thickness of sprayed paint coatings on vehicle instruments, controls and airbag cladding – during the spraying process itself whilst the paint is still wet. The sensor system is non-contact, easy to mount and offers high accuracy when used against shiny black PU surfaces.

To perform the required thickness measurements, Micro-Epsilon’s ‘EU15 (05)’ eddy current sensor is used in combination with the company’s ‘optoNCDT’ laser-based optical triangulation sensor. The eddy current sensor measures the distance to the spray mould. The sensor has an opening in the centre, through which the optoNCDT laser sensor measures the distance to the sprayed component.

The eddy currents pass through the sprayed skin to the nickel-coated spray mould. The laser sensor supplies the reference distance to the skin surface. These processed signals are then subtracted from one another to provide an accurate measurement of the thickness of the applied paint skin.