Radar sensor for monitoring the injection moulding processes

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.