The paper describes some new developments in the field of contactless and nondestructive determination of the layer and coating thickness on different substrates. 1) The first method is based on millimeterwaves which are emitted and re-ceived by a compact integrated radar sensor. 2) Another approach is based on thermal effects induced in the coating by flash heating or laser light heating. The temperature response of the test object is monitored by an infrared sensor. 3) With the help of an airborne ultrasonic transducer the thickness of powder coating, e.g. ceramics-coating on steel, can be determined contactlessly with an accuracy of better than 5 μm.
A compact and high integrated radar sensor working in the millimeterwave range can be applied for monitoring the injection moulding processes with and without gas assistance. The millimeterwaves are introduced into the cavity by a hollow waveguide and by a window transparent to millimeterwaves. In the frame of injection moulding experiments the process has been recorded simultaneously optically and by millimeterwave radar. When the melted plastics or the gas bubble are passing over the position of the sensor window, the signal of the sensor is abruptly changing both with regard to amplitude and phase thus indicating if the process is running correctly or not. The experimental investigations have been complemented by simulation calculations.