Abrasive Waterjet vs. Pure Waterjet Cutting

The primary difference lies in the cutting medium. Pure waterjet cutting uses only a high-pressure stream of water (typically 30,000–90,000 psi) focused through a tiny orifice. This creates a fine, needle-like jet that cuts by eroding soft materials. It is ideal for materials that are soft, thin, or sensitive to contamination. Common applications include cutting foam, rubber, gaskets, food products, paper, plastic films, and corrugated cardboard. The main advantages are zero abrasive contamination, very small kerf (as narrow as 0.003"), and extremely clean edges. However, pure waterjet cannot effectively cut hard materials like metal, stone, or glass.

Abrasive waterjet cutting works by mixing granular garnet (or other abrasive) into the high-pressure water stream inside a mixing tube. The water accelerates the abrasive particles, creating a highly erosive jet that cuts virtually any solid material. By adding abrasive, the same water pressure can slice through titanium, hardened steel (up to 6+ inches thick), granite, ceramic, bulletproof glass, and carbon fiber composites. The abrasive dramatically increases cutting power, but also widens the kerf slightly (0.02"–0.05") and leaves a rough, sandblasted edge finish that may need secondary processing. Abrasive consumption also adds ongoing operational cost.

Key takeaway: Use pure water for soft, thin, or contamination-sensitive materials. Use abrasive water for hard, thick materials where cutting power matters more than cost or edge finish. Many industrial waterjet systems offer both modes, switching instantly by turning the abrasive flow on or off.