Waterjet cutting and laser cutting are both CNC-controlled precision cutting processes, but they work very differently and excel in different applications. Here is a practical comparison to help you choose the right method for your project.

How Each Process Works

Waterjet cutting uses a high-pressure stream of water — often mixed with abrasive garnet — to erode material along a programmed cut path. It is a cold process: no heat is applied to the material.

Laser cutting uses a focused beam of high-energy light to melt or vaporize material along the cut line. It is a thermal process — heat is always involved.

Materials: Where Each Process Wins

Waterjet handles a wider range of materials. It can cut metal, stone, glass, ceramic, composites, rubber, foam, and plastics. It is especially valuable for materials that cannot tolerate heat — like hardened steel, titanium, composites, and glass.

Laser cutting is excellent for thin to mid-thickness metals and some plastics, but it cannot cut stone, glass, or most composites. Reflective metals like copper and brass are difficult for standard CO2 laser systems.

Heat-Affected Zone

This is one of the most important differences. Laser cutting generates significant heat, which creates a heat-affected zone along the cut edge. This can alter the material's hardness, temper, and grain structure — which matters for aerospace components, hardened steel, and heat-sensitive alloys.

Waterjet has zero heat-affected zone. Because no heat is generated, the material's properties are fully preserved at the cut edge. This makes waterjet the preferred choice for applications where material integrity is critical.

Tolerances and Edge Quality

Both processes can achieve tight tolerances. Laser cutting generally offers slightly finer tolerances on thin sheet metal and can achieve very smooth edges on steel and aluminum.

Waterjet tolerances of plus or minus 0.005 to 0.015 inches are standard, with better tolerances achievable at slower speeds. Waterjet edge quality on metal is typically smooth and requires no secondary finishing.

Material Thickness

Laser cutting is fastest on thin to medium material thicknesses — typically under 1 inch for most metals. Performance degrades on thick material.

Waterjet handles greater thicknesses. Depending on material, waterjet can cut several inches of steel or stone — thicknesses that would be impractical or impossible for laser.

Cost Comparison

Laser cutting is often faster (and therefore cheaper per part) on thin sheet metal in high volumes. Waterjet is more cost-effective for thick materials, stone, glass, composites, or materials that would be damaged by laser heat.

Side-by-Side Summary

Heat-affected zone: Waterjet has none. Laser always has one.
Materials: Waterjet cuts nearly anything. Laser is limited to metals and some plastics.
Glass and stone: Waterjet yes. Laser no.
Thick materials: Waterjet yes. Laser is limited.
Thin metal speed: Waterjet is moderate. Laser is fast.
Edge quality: Both are very good, with laser slightly ahead on thin metals.

Which Should You Choose?

Choose waterjet if your material cannot tolerate heat, you are cutting stone, glass, or composites, you need to cut thick material, or material integrity is critical.

Choose laser if you are cutting thin sheet metal at high volume and heat is not a concern.

Still unsure? Contact Interwest Manufacturing and describe your project — we can advise on the right approach.

Waterjet Cutting vs. Laser Cutting: Which Is Right for Your Project?