The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 02, 1995
Filed:
Oct. 08, 1992
Stephen A Burgis, Birmingham, MI (US);
Design-Rite, Inc., Sterling Heights, MI (US);
Abstract
A gas control unit for a gas-assisted injection molding system, wherein a quantity of gas is introduced into a mold cavity in combination with a quantity of plastic material during the molding process. The gas control unit operates on the basis of regulating the mass of gas within the system, as opposed to the final hold pressure. Because the mass of the gas is constant within the gas control unit throughout an injection cycle, a preferred initial-to-final (hold) pressure ratio can be determined through mathematical computations for a particular molding system. As a result, once the required mass of gas has been isolated from a suitable source, releasing the gas to the mold cavity results in a predictable pressure. This capability permits the gas control unit to determine whether the gas has fully expanded and, therefore, whether the gas has properly filled the mold cavity so as to produce a properly molded article.