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 |
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.
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