Abstract: An apparatus and process for expanding polymeric tubing including a bubble of trapped gas within the polymeric tubing. The tubing is expanded by creating a pressure differential between the inside and outside of the tubing such that the pressure inside the tubing is greater than the pressure outside the tubing, thereby causing the tubing to expand. It is possible with the present invention to compensate for loss of gas pressure, thereby increasing the amount of tubing which can be expanded without ceasing production and restarting the process.

Abstract: A plasticized resin is extruded from an extruding machine into an accumulator into which the resin is stored by an amount exceeding the amount required for one resin molding operation. The stored resin, in operation, is fed through a flexible hose towards a gear pump under controlled pressure conditions. The resin is measured by the gear pump and the displacement and the rotational speed of the gear pump are controlled by a suitable controller such as microcomputer to exactly measure the plasticized resin to be charged into the mold cavity in a predetermined distributing mode. The clamping of the mold can be effected by a clamping force less than that required by a conventional press-molding machine.