8456.40 - Operated by plasma arc process:

This HTS category, 8456.40, encompasses machine tools that utilize a plasma arc process to work materials through material removal. This technology involves generating and directing a high-temperature plasma stream to ablate, melt, or vaporize material, thereby shaping or cutting the workpiece. These machines are designed for precision manufacturing and are employed across various industries for tasks such as cutting, engraving, and surface treatment.

It is important to distinguish 8456.40 from its sibling categories within the broader 8456 heading. While all machines in heading 8456 work material by removal, this specific sub-heading is exclusively for those employing *plasma arc processes*. This differentiates them from machines that operate using laser or light beams (8456.10), ultrasonic energy (8456.20), electro-discharge processes (8456.30), or water-jet cutting (8456.50). The distinguishing factor lies solely in the energy source and mechanism of material removal.

Within this plasma arc category, two subcategories exist to further refine the classification. **8456.40.10** is designated for machines specifically designed for working *metal*, indicating their application in metallurgical industries. The remaining machines operating by plasma arc process, but not exclusively for metalworking, fall under **8456.40.90.00**, which covers all *other* applications of this technology.