molten metal is introduced into the cavity by a combined gravity feed and centrifugal force feed using a rotating turntable under electrical or electronic control . the centrifugal force is controlled to be substantially constant until the metal has solidified . this is accomplished by controlling the ramp - up acceleration of the turntable where rotational velocity is a time - dependent function of rotational radius and molten metal mass and taking into account the flow rate and cooling rate of the liquid metal . the process reduces waste and the attendant energy consumption associated with the quantity of metal required to be melted for the initial pour and associated with reprocessing and reusing the waste component .