Surveillance of gas assisted injenction moulding process by means of microwaves

An innovative method for online surveillance and control of the gas assisted injenction moulding process (GIT technique) has been developed. It is based on radar sensors which emit microwaves into the cavity and receive the scattered microwaves with the same antenna. Depending on sensor type the frenquency is in the range between about 24 GHz and 94 GHz. Especially the correct position of the gas bubble can be monitored. By using a two axis scanning equipement it is possible to generate two dimensional images and to detect defects, e.g. bubbles, inside injenction moulding parts.