Improvements in or relating to injection systems

A method of operating injection moulding apparatus including a mould having an inlet and an outlet, an inlet line connectable to the inlet of the mould, and outlet connectable to the outlet of the mould, an injector connectable to the inlet line and configured for injecting liquid resin into the mould through the inlet line, a processor configured for controlling the injector for at least one injection moulding cycle to inject a prescribed amount of liquid resin into the inlet line, and a resin detection system located in the outlet line and configured for detecting the presence of liquid resin in the outlet line and for providing at least one signal indicative of the detected liquid resin in the outlet line, the resin detector system comprising a valve and at least one sensor located in a predetermined position with respect to the valve, the at least one signal being used for closing the valve, the method comprising the steps of:

• a) performing a vacuum leak test on the apparatus prior to injecting liquid resin;
• b) if conditions for the vacuum leak test are met, injecting a prescribed quantity of liquid resin into the mould;
• c) detecting the presence of liquid resin in the outlet line;
• and
• d) operating the valve in the outlet line to terminate flow of resin therethrough in response to the detection of the presence of liquid resin in the outlet line.