Polymeric foam processing systems and methods

A method of processing polymeric foam material comprising:

• providing an extruder including a screw mounted in a barrel, the screw designed to include a mixing section and a downstream end of the screw;
• rotating the screw to convey polymeric material downstream in a processing space within the barrel while maintaining a back pressure of Pb on the screw when the screw rotates to convey polymeric material;
• introducing blowing agent from a blowing agent source through a blowing agent port formed in the barrel at a blowing agent receiving section of the screw to form a mixture of blowing agent and polymeric material in the processing space, wherein the blowing agent concentration in the mixture is C;
• moving the screw in a downstream direction in the barrel to an injection position to inject a shot of polymeric material and blowing agent into the mold, the shot having a volume of Vs;
• and
• recovering a polymeric foam article from the mold,
• wherein a mixing volume of Vm is defined as the volume of the mixture of blowing agent and polymeric material in the processing space between the blowing agent receiving location of the screw and the downstream end of the screw when the screw is in the injection position;
• and
• wherein the method operates at an effective solubility ratio characterized by:
• Effective Solubility Ratio=Pb/(C×Vr)
• wherein Vr=Vs/Vm,
• wherein the effective solubility ratio is greater than 1500.