The SITC classification explicitly separates the two because flexographic presses use flexible elastomeric or photopolymer plates, fast-drying liquid inks, and are engineered for high-speed continuous-web substrates (films, foils, corrugated board) — a distinct industrial application from traditional rigid-plate letterpress. The exclusion ensures that flexo equipment, which dominates flexible packaging printing, is tracked and classified under its own dedicated heading (72663).

Combination platen presses that perform both letterpress printing and die-cutting in a single pass are generally classified by their principal function. If printing is the primary purpose and die-cutting is ancillary, the machine falls here; if die-cutting dominates, it may be classified as a cutting machine. Importers with true dual-function equipment should seek a CBP binding ruling to confirm the correct heading.