Laser cutting, plasma cutting, and waterjet cutting are all viable methods to cut sheet metal. So, how do you choose the right one for your shop before you invest in new equipment? In this guide we’ll be covering the advantages and limitations of each technology so that you can select the best option to serve your fabrication facility for years to come. Without further ado, let’s begin with laser cutting.
Laser Cutting
Laser cutting can encompass a wide range of processes, but in this case we will be referring to fiber laser cutting. Fiber laser cutting is the latest iteration of commercialized laser cutting, succeeding CO₂ laser technology. Fiber laser cutting machines utilize a shorter wavelength of concentrated light to achieve a more focused, high-precision laser beam that can cut at higher speeds, all while consuming less energy than a comparable CO₂ laser.
Precision & Finish
The diameter of the laser beam, a measurement also known as its kerf, is one of the key advantages of fiber laser cutting technology. Fiber lasers offer the greatest precision capabilities of the three cutting methods covered in this article, making them a preferred choice for metal fabricators wanting to produce neatly-cut blanks or even near-net finished parts. They can also easily handle thin metal sheets with little to no warping, and medium metal sheets without compromising edge quality. Depending on the laser and the project material, some machines can cut through thicker materials with ease—for instance, a 6kW fiber laser can cut through a 1in. mild steel plate.
Material Compatibility
If material versatility is a concern, laser cutting machines can also be used to cut a variety of nonmetals including wood and acrylic. In the past, water jet cutting may have been a more viable choice for working with highly reflective metals like aluminum and titanium. However, now that fiber lasers have become the leading tech often used in favor of CO₂, processing those same reflective materials with a laser cutting machine has become a nonissue.
Costs
In terms of startup costs, fiber laser cutting machines can be customized to find the ideal balance between your budgetary needs and your production needs. Fiber laser cutters are also very affordable to operate, with its solid-state laser contributing to low energy consumption. When you consider that most laser cut parts will not need additional finishing, fiber laser cutting comes out on top as the most economical choice when applicable.
Want to find out if laser cutting is right for you? Contact Universal Tool & Engineering for a free consultation and no-obligation part sample.
Plasma Cutting
In plasma cutting, a pressurized stream of superheated compressed gas—known as plasma—is ejected from the cutting nozzle to cut through a sheet of material. Unlike laser cutting and waterjet cutting, plasma cutting is only compatible with electrically conductive materials which limits its use to metals. Since plasma cutting does leverage a metal’s conductivity, it is often a better option than laser cutting for processing thick plates as the plasma stream has no trouble traveling through the material.
Cost
By comparison with laser cutting and waterjet cutting, plasma cutting has the most affordable setup cost. However, be wary of the low price tag. What you don’t spend on the cutting equipment, you will likely spend elsewhere in finishing equipment and labor. Although the up front cost is lower than the other two methods, it’s worth considering that the level of precision that can be achieved with a plasma cutter does not come close to what you can get with another type of cutting machine. As far as operational costs, it’s more expensive than laser cutting, but not nearly as costly as waterjet cutting thanks to its low demand for consumables.
Precision & Finish
This technology does come with some drawbacks. Although plasma cutters can make quick work of thick metal plates, the plasma stream is quite imprecise. Plasma cuts will almost always require secondary finishing methods to achieve a clean edge. In addition, the high heat exposure that comes with plasma cutting often results in a wide heat-affected zone (HAZ) in which the metal closest to the edge will display different properties from that in the middle of the workpiece.
Waterjet Cutting
Waterjet cutting is the most unique of the three processes. Unlike plasma cutting and laser cutting, waterjet’s primary method of slicing through material is not by using heat, but by using abrasion. Due to the extreme compression, the water in the machine does become warmer than room temperature, but not nearly hot enough to melt through most materials. Instead, the water is ejected from an orifice smaller in diameter than that of a needle, resulting in a travel velocity comparable to that of a bullet from a gun barrel. This cutting method gives waterjet cutters a couple of distinct advantages over plasma cutting and laser cutting in certain scenarios.
Material Compatibility & Condition
For one, waterjet machines can cut a few materials that both lasers and plasma cutters cannot—namely, a selection of nonmetals. Some of these materials include carbon fiber, PE foam, PS foam, and some specialty resin composites.
In addition to those materials, waterjet machines can also cut through many materials that laser cutters can, including metals, wood, acrylic, and glass, making them an arguably more versatile option for nonmetal cutting applications. Another advantage of waterjet cutters is that they do not create a HAZ on any materials. In some laser cutting and especially plasma cutting, the HAZ around the cut edges can display slightly (or drastically) different properties from the inner piece as a result of high heat exposure. In waterjet cutting, the jet stream is not heated to extreme temperatures, which eliminates the possibility of a HAZ on the final part. So, if avoiding work-hardening or distortion is a major concern, waterjet cutting may be your answer.
Costs
Where waterjet cutting starts to lose its luster is in its operating costs. Waterjet cutters are very demanding, as they require a large, steady supply of clean water, sometimes abrasive additives, a power source, a compressor, frequent cutting tip changeovers, and more water. In addition to the water that is ejected from the cutting tip nozzle, a pool of water must be maintained underneath the workspace to dissipate the highly pressurized waterjet stream. Depending on the power of the waterjet, this pool can be greater than 3 feet deep. With high energy consumption and high water consumption, waterjet cutting will hardly ever be the most economical choice.
Precision & Finish
A notable limitation of waterjet cutting is that the kerf of the jet stream is significantly larger in diameter than what can be achieved with a fiber laser cutting machine. As a result, inner corners formed with a waterjet cutter will have more of a radius to them and lack the definition that a laser-cut piece might display. Additionally, the cutting process will leave a small notch where the cut starts and stops which will require secondary finishing to remove.
Thinking about making the switch? Speak with Universal Tool & Engineering to find out how a fiber laser machine can boost part quality and your budget.
CNC Sheet Metal Cutting FAQ
Q: What tolerances can laser cutting achieve compared to waterjet or plasma?
A: Laser cutting can consistently achieve very tight tolerances—often ±0.001\”” or better—due to precise beam control and minimal kerf width, outperforming plasma and often matching or exceeding waterjet in many applications.
Q: Which materials can each method cut (metals, composites, stone etc.)?
A: Laser is excellent for most metals (steel, stainless, aluminum) and some plastics; waterjet handles almost any material including stone, composites, glass, and layered materials; plasma works only on electrically conductive metals.
Q: Is there a maximum thickness for laser cutting?
A: Yes—laser cutting works best up to a certain thickness (varies by power) beyond which speed and quality drop; for heavy plate thicknesses, plasma or waterjet may be more economical.
Q: Does laser cutting cause thermal damage or warping?
A: Laser cutting generates a heat-affected zone (HAZ), but with proper settings and cooling, distortion can be minimized. Waterjet produces no HAZ, and plasma HAZ is larger.
Q: What is the average cost difference between methods?
A: Laser has higher capital cost but lower per-part finishing and high throughput. Waterjet has high consumables (abrasive, pump wear). Plasma costs less per cut but often requires post-processing.