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:
Jul. 27, 1999
Filed:
Dec. 13, 1996
Toshiba Machine Co., Ltd., Tokyo, JP;
Abstract
The present invention provides a method of control in thickness of the biaxially oriented film of a plastic material to be extruded via an extrusion port gap adjustable by adjustment of a plurality of die bolts provided on an automatic T-die. A position corresponding to the die bolt is set on the film biaxially oriented so that a thickness of the film at the above position is measured to find a deviation of the measured thickness from a reference thickness predetermined to thereby carry out a feed-back control of the adjustment of the die bolt in accordance with the deviation. It is important for the present invention that the feed-back control in the adjustment of the die bolt is carried out with reference to partial side-drawing rates different in a width direction of a sheet to be drawn prior to formation of the film, where the partial sidedrawing rates are determined for parts aligned in the width direction of the film. The determination of the partial side-drawing rates are made together with setting a corresponding position on the sheet to the die bolt.