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. 25, 1976
Filed:
Jan. 30, 1974
Egon Bussmann, Munich, DT;
Walter Pritzl, Munich-Unterhaching, DT;
Siemens Aktiengesellschaft, Berlin & Munich, DT;
Abstract
Process and apparatus for automatic checking and control of etching machines which provides a signal related to the strength of the etching solution and provides means whereby the length of etching time can be varied in relation to the concentration of the etching solution. The present invention provides a system including a measuring compartment through which an etching solution from the etching machine is constantly circulated. A measuring wire is inserted into the measuring compartment and held stationary therein for a time sufficient to cause the etching solution to etch away an end portion of the wire. The time required to etch off this end portion is measured and provides an analog signal of etching solution strength which is proportional to etching time. This signal can be used to control the feed of the etching machine so that as the solution becomes less concentrated, the time of exposure of the material being etched is increased.