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:
Sep. 17, 2002
Filed:
Oct. 19, 1999
Helmut Eckardt, Meinerzhagen, DE;
Jurgen Ehritt, Hilchenbach, DE;
Battenfeld GmbH, Meinerzhagen, DE;
Abstract
A method for injection molding plastic molded parts from thermoplastic, comprises the following steps: the production of a thermoplastic melt ( ) through the rotation of a plasticizing and injection screw ( ) in a preplasticizing cylinder ( ); the addition to the thermoplastic melt ( ) of a fluid ( ) by introducing the fluid ( ) into the preplasticizing cylinder ( ); the mixing up the thermoplastic melt ( ) to which the fluid ( ) has been added, through the rotational motion of the plasticizing and injection screw ( ); the injection of the mixture of thermoplastic melt ( ) and fluid ( ) into the cavity ( ) of an injection molding tool ( ). In order to make this method suitable especially for the reliable and reproducible production of large, foamed plastic molded parts, the invention is characterized in that the mixture of thermoplastic melt ( ) and fluid ( ) is injected into the cavity ( ) of an injection molding tool ( ) through the translational motion of the plasticizing and injection screw ( ), the fluid ( ) is introduced into the preplasticizing cylinder ( ) at an axial position ( ) where the screw channels ( ) of the plasticizing and injection screw ( ) are situated at least some of the time, and the pressure difference (delta p) between the pressure (P ) of the fluid ( ) and the pressure (p ) in the thermoplastic melt ( ) is maintained essentially constant while the fluid ( ) is being introduced into the preplasticizing cylinder.