Ultrasonic injection moulding

A method of injection moulding comprising the steps of:

• providing an apparatus having a flow chamber that is formed in an injection moulding assembly and includes:
• an ultrasonic vibration device comprising a sonotrode, and
• an outlet through which injection moulding material can pass from the flow chamber towards a mould tool cavity;
• wherein the sonotrode is at least partially arranged in the flow chamber;
• using the injection moulding assembly to injection mould a part, such that injection moulding material flows along an outer wall of the sonotrode by:
• starting an injection cycle by using the injection moulding assembly to initiate a flow of molten injection moulding material from the flow chamber through the outlet;
• simultaneously with flow initiation through the outlet, or after the flow has been initiated, turning the ultrasonic vibration device from an off-state to an on-state to expose the molten injection moulding material in the flow chamber to ultrasonic vibration during flow;
• and
• turning the ultrasonic vibration device from the on-state to the off-state when the mould tool cavity is full, such that static molten injection moulding material in the flow chamber is not exposed to ultrasonic vibration before the next injection cycle is started.