8456.20 - Operated by ultrasonic processes:

This HTS category, 8456.20, specifically encompasses machine tools that employ ultrasonic processes for working materials. These machines utilize high-frequency sound waves, often transmitted through a liquid medium, to erode, cut, or surface finish a wide range of materials. This process is distinct from methods that rely on thermal energy like lasers, or electrical discharges, or physical removal by cutting tools.

Machines classified under 8456.20 are differentiated from their siblings by their unique operating mechanism. For instance, they are not operated by laser or other light or photon beam processes (8456.10), nor by electro-discharge (8456.30) or plasma arc processes (8456.40). Furthermore, they are separate from water-jet cutting machines (8456.50.00.00), which use a focused stream of water, potentially with abrasives, as their cutting medium. The defining characteristic here is the exclusive use of ultrasonic energy.

The subcategories within 8456.20 further refine classification based on the intended application of these ultrasonic machine tools. 8456.20.10 is designated for machines specifically designed for working metal, indicating a focus on operations such as drilling, cutting, or shaping metallic components. The broader category, 8456.20.50.00, covers all other applications of ultrasonic processing not specifically related to metalworking, which could include materials like glass, ceramics, or certain composites.