US 7,320,765 B2
Gas pin for thermocouple for gas assisted injection molding
Gregory A. Homann, Canton, Mich. (US); and James Hendry, Brooksville, Fla. (US)
Assigned to International Automotive Components Group North America, Inc., Dearborn, Mich. (US)
Filed on Apr. 30, 2004, as Appl. No. 10/709,388.
Prior Publication US 2005/0242475 A1, Nov. 03, 2005
This patent is subject to a terminal disclaimer.
Int. Cl. B29D 22/00 (2006.01)
U.S. Cl. 264—40.1  [264/572; 425/130; 425/143] 16 Claims
OG exemplary drawing
 
1. A method of forming an injection molded part in a mold cavity comprising:
charging a first volume of gas in a fixed volume reservoir;
introducing a first volume of plastic material into the mold cavity through a gas pin, said gas pin incorporating a temperature sensing device;
determining the temperature of said plastic material in the mold cavity;
introducing said first volume of gas into said first volume of plastic material when said temperature of said plastic material reaches a predetermined value, said first volume of gas forming a hollow cavity in said plastic material;
filling said mold cavity with plastic material;
injecting a second volume of gas into the hollow cavity in said plastic material;
allowing said plastic material to cool;
venting at least said second volume of gas from said plastic material; and
removing said cooled plastic material from said mold cavity.