Class 216 is an integral part of Class 156. It incorporates allthe definitions, rules, and hierarchy pertaining to subject matterof Class 156.
GENERAL STATEMENT OF CLASS 216 SUBJECT MATTER:
This is the Generic class for chemical etching processes fortreating articles of commerce or intermediate articles not otherwiseprovided for in which one of the manufacturing steps includes achemical etching step (use of an etchant) and wherein the materialtreated is not completely removed.
(1)Note. The chemical etching required for placement in thisclass is any intentional change of shape of an article or substrateby the removal of material involving a chemical reaction or physicalsolvation using a chemical agent (the etchant). This is the residualclass for removing a surface by chemical reaction or solvent actionregardless of the substrate acted on. Bright Polishing of a metalwith acid solution is considered etching and appropriate for this class.The processes of the patents in this class often include the formationof a design, but the production of a design is not required to placethe patents here.
(2)Note. Reduction in size using a chemical etchant of an unmaskedarticle, substrate or unmasked geometric figure, e.g., sphere, etc.is proper for this class.
(3)Note. Etching of a masked article, to direct the etchantto only a portion of the article or substrate is proper for thisclass.
(4)Note. This class is not intended for the total dissolvingof an article or substrate. Furthermore, the remaining articleor substrate must be the desired product and not the removed material.An example of a process not proper for Class 216 would be ore beneficiatingwhere the dissolved material is what is desired and useful and notthe remaining residue material. Additionally a process of dissolvingout impurities or unwanted material to leave a desired article isproper for this class when said process is not provided for elsewhere.
(5)Note. Chemical milling is considered within the scope ofthe term etching.
(6)Note. Class 216 provides only for etching processes. Etchingcompositions are elsewhere. See Lines With Other Classes, below.