When it comes to cutting parts, the list of preferred methods can get quite long. From saw cuts and flamed parts, to plasma torches and EDM machines, it can be difficult to weed through all of the options. Thankfully, there are two tried and true methods that have proven to be some of the most effective and efficient cutting solutions in the industry and those are water jet and laser.

These two cutting methods share many similarities, but there are a few key differences worth noting. Below, we’ll take a closer look at the water jet and laser cutters to see how they compare.

The Material Being Cut

Water jet: A water jet cutter has little to no restrictions when it comes to materials that it can cut. The water jet cuts without introducing heat into the stock, and this avoids any adverse effects that might otherwise occur (melting, work hardening, warping, burning, etc.) Common material types cut on a water jet include (but are not limited to) plastic, rubber, composites, stone, tile, aluminum, copper, brass, titanium, stainless steel, tool steel and more.

Laser: The laser cutter is capable of cutting a wider range of metals including stainless and carbon-based steels, as well as aluminum and a select assortment of alloys. Certain lasers can cut through non-conductive materials like wood, glass or plastic but heat can play a factor and will affect the end product if not taken into account. Certain reflective metals can also be problematic for a laser due to interference from the laser beam bouncing off of the material surface.

The Thickness Of The Material

Water jet: The water jet has few limitations in terms of thickness. Its cutting range is generally touted as .001” – 15” thick (though it is less common that there would be a demand to cut such a thick piece of material.)

Laser: Most production style lasers found in the average machine shop can cut up to 3/4” in certain metals, but the quality and effectiveness will vary depending on the material. A max thickness for aluminum will be lower than a carbon steel, due to its ability to hold up under the heat that is introduced from the laser beam. The benefit of the laser cutter is its ability to cut thinner material at a far higher rate of speed than the water jet. In thickness of 1/4” and less, the laser would be the more cost-effective option when cutting metals.

The Accuracy And Quality Of The Cut

Water jet: The cutting stream of a water jet is typically .030”-.040” in diameter. The water jet is capable of cutting with an extremely fine surface finish, almost machine quality in some instances, though it will have a slight taper from the top of the cut to the bottom. This angle is known as kerf, and is common in water jet components. Cutting tolerances on the water jet are +/-.005” on thinner jobs, but that range will widen as material gets thicker.

Laser: The cutting path of a laser is much thinner than a water jet, which can be a benefit when cutting tight geometry on small parts, or when components need to be nested close together. A laser cutter is more accurate than a water jet in most instances, with a cut tolerance as little as +/- .002”. Laser cutters can leave a clean surface finish on cut profiles, though it will be striated as thickness and/or speed increase.

The Bottom Line

Water jet: An accurate and versatile machine that can cut the widest range of material types/thicknesses. Though not as fast as a laser in certain materials, a water jet provides precise cuts with a high quality finish all without the risk of negative heat-related side effects

Laser: Laser cutters are incredibly fast and accurate. It all comes down to material and thickness, but in the right instance the speed, quality and precision of a laser is unmatched. On thicker materials, or when heat is a concern, it would be better to find an alternative cutting method.