What Is Waterjet Cutting? How It Works and What It Can Cut

Waterjet cutting is a manufacturing process that uses a high-pressure stream of water — sometimes mixed with an abrasive material — to cut through a wide range of materials with extreme precision. It is one of the most versatile cutting methods available, capable of processing everything from thin sheet metal to thick granite slabs without applying heat.

How Does Waterjet Cutting Work?

A waterjet cutter pressurizes water to extremely high levels — typically between 40,000 and 90,000 PSI — and forces it through a small nozzle to create a focused, high-velocity stream. This stream is directed at the material being cut, eroding it along the programmed path.

For harder or thicker materials, a fine abrasive (usually garnet) is mixed into the water stream. This is called abrasive waterjet cutting, and it dramatically increases cutting power, allowing the system to cut through thick steel plate, titanium, stone, glass, and composites.

The cutting path is controlled by a CNC system, which follows a design file — typically a DXF, DWG, or AI file — to produce precise, repeatable cuts.

What Materials Can Waterjet Cut?

Waterjet cutting can process virtually any material, including metals (steel, stainless steel, aluminum, copper, brass, titanium, and exotic alloys), stone (granite, marble, limestone, travertine, and slate), glass (plate glass, annealed glass, and laminated glass), ceramics (porcelain tile and ceramic), composites (carbon fiber, fiberglass, and laminates), plastics (acrylic, polycarbonate, HDPE, and more), rubber and foam, and wood and MDF.

Materials that waterjet does not cut well include glass that has already been tempered, because cutting releases the internal stress and causes the panel to shatter. If a project needs tempered glass, the cuts and holes should be made before the glass is tempered.

Pure Waterjet vs. Abrasive Waterjet

There are two main types of waterjet cutting.

Pure waterjet uses only water and is best for soft materials like rubber, foam, food products, and thin plastics. It produces very fine, precise cuts with minimal material waste.

Abrasive waterjet adds garnet to the water stream and is used for hard materials like metal, stone, and glass. It cuts thicker cross-sections and harder materials, though slightly slower than pure waterjet on soft materials. Most industrial and manufacturing applications use abrasive waterjet cutting.

Advantages of Waterjet Cutting

No heat-affected zone: Because waterjet is a cold-cutting process, there is no heat applied to the material. This preserves the metal's temper, hardness, and structural integrity, and eliminates warping or discoloration.

No secondary finishing required in most cases: Waterjet produces smooth, clean edges that typically do not need grinding, deburring, or additional finishing — saving time and cost.

Cuts almost anything: No other single cutting process handles the range of materials that waterjet does.

Tight tolerances: Modern CNC waterjet systems can hold tolerances of plus or minus 0.005 inches or better, making them suitable for precision industrial parts.

Minimal material waste: The waterjet kerf (the width of the cut) is very narrow, meaning less material is lost compared to other cutting methods.

When to Use Waterjet Cutting

Waterjet is the right choice when the material cannot tolerate heat, when you need to cut a material that is difficult for laser or plasma (stone, glass, thick metals), when you need complex shapes cut directly from a CAD file, when you need clean edges without secondary operations, or when you are cutting stacks of material or multiple layers.

Waterjet Cutting Services in Utah

Interwest Manufacturing operates a Flow Waterjet system in North Salt Lake, Utah, with a 6 by 12 foot cutting table. We provide waterjet cutting services for businesses throughout Utah including Salt Lake City, Ogden, Provo, and the Wasatch Front.