Machines that form cartons or boxes by mechanically folding, scoring, and gluing pre-cut paperboard blanks are classified here. Machines that shape wet paper pulp in molds — producing egg trays, cup carriers, or similar molded-fiber products — fall under the separate heading for pulp-molding machinery. The process method (mechanical forming vs. wet molding) is the decisive criterion.

An in-line machine that combines printing with carton forming should be classified by its principal function. If the primary commercial value and design intent is carton forming and the printing is ancillary, classification here may be appropriate; if printing is the dominant function, the machine may belong under printing machinery. A binding ruling from CBP is advisable for high-value integrated lines.