Laser Cutting vs Plasma Cutting: Speed, Materials, Cost, and more
Learn more about the diffrences between these two processes.
Laser and plasma cutting are both methods well-suited to CNC (Computer Numerical Control) machining production processes. Both of these technologies are thermal processes commonly used in industrial settings to cut materials. The main difference between the two technologies lies in the source of the technology's cutting power: laser cutting machines use a narrow and intense ray of light to cut through materials, whereas plasma cutters use a device for generating a directed flow of plasma for cutting.
Laser cutting can be used to cut a wide range of materials, including ceramic, wood, plastics, and metals, whereas plasma cutting can only be used to cut conductive materials. Laser cutting is faster, more accurate, and produces a better surface finish than plasma cutting. The laser method is also better suited for making intricate cuts than plasma cutting. On the other hand, plasma cutting machinery requires less maintenance and is less costly than laser cutting equipment. Both technologies are mainly used to cut metals, although laser cutting is also commonly used for other materials as well.
Selecting the right CNC cutting process for your needs can depend on many factors. In this article, we compare laser cutting and plasma cutting in terms of speed, materials, cost, and other factors that distinguish these two techniques.
Laser cutting works by directing the highly concentrated energy of a laser beam directed onto a material, producing local melting and separation of the workpiece. Depending on the details of the cutting technique, the laser may melt the material, with an assistive gas stream blowing the melted material out of the way. Or it may directly change the cut material from solid form to gas (sublimation), with the kerf removed in vapor form. Laser cutting equipment can cut structural and pipe materials as well as thin sheets.
Three main types of lasers are used for laser cutting: CO2, neodymium, and fiber laser systems. Although the laser cutter types are all similarly constructed, they differ in that each kind of laser has a different power range, and each is best suited to certain material types and thicknesses. With CO2 cutters, the cutting is done using electrically-stimulated CO2. Neodymium, or crystal laser cutters, produce beams through Nd: YVO (neodymium-doped yttrium ortho-vanadate) and Nd: YAG (neodymium-doped yttrium aluminum garnet). Finally, fiber cutters use fiberglass to cut through materials. The lasers are derived from what’s called a ‘seep laser’ and are thereafter amplified through special fibers.
CO2 lasers are the most popular because they can cut a variety of materials, are low-power, and are reasonably priced.
Laser cutting is widely used in sectors like electronics, medicine, aircraft, and transportation. Due to the laser’s ability to create precise cuts and finishes, it is mostly used to cut metals like tungsten, steel, aluminum, brass, or nickel. Lasers are also used to cut wood, silicon, ceramics, and other non-metals. Figure 1 is an example of a laser cutting machine:
Figure 1: Laser Cutting Machine - Image Credit: Shutterstock/Roman Zaiets
Laser cutting machines have the following advantages over their plasma cutter counterparts:
- Accuracy: The energy of a laser beam is concentrated on a single tiny area, penetrating the material and cutting it. This process produces a thin cutting seam (kerf) in the workpiece, as opposed to the wider kerf produced by plasma cutting. The thinner cut made by a laser makes it useful for complex, delicate cutting tasks that cannot be accomplished by a plasma cutter.
- Wide Range of Materials: Laser cutters are capable of cutting a wide range of materials, including: metal, wood, plastics, and ceramics. Plasma cutters, on the other hand, are limited to cutting conductive materials.
- Speed: Laser cutters are a more energy-efficient and faster option for cutting metal compared to plasma cutters, making them a better choice for the environment.
Laser cutters have the following disadvantages when compared to plasma cutting machines:
- Reflective Materials: Compared to plasma cutting, laser cutting does not perform as well on highly reflective surfaces like metal.
- Material Thickness: In general, laser machines do not have enough power to cut through materials thicker than 19 mm, whereas plasma cutters are able to cut metal plates with a thickness of up to 38 mm.
- Capital Investment: Capital costs for a laser cutter are significantly higher than for a plasma cutter.
Plasma cutting is a cutting technology that works by forcing a hot, electrically charged gas through a small nozzle to hit the workpiece at high velocity and pressure, eroding and melting a cutting path through the material. Essentially, compressed air or inert gasses like argon or nitrogen are forced through a small nozzle at high speeds. The combination of gas, high speed, pressure, and an external electric charge form the plasma, which is an electrically conductive ionized gas that can reach temperatures of up to 20,000 °C. Similar to a laser cutter, a plasma cutter is a thermal cutting method where the material is melted in order to cut through it.
Steel, stainless steel, aluminum, brass, and copper are among the common materials cut with a plasma torch. Only conductive metals can be used with plasma torches because the workpiece completes the electrical circuit. Plasma cutters are widely used in fabrication shops, auto repair and restoration, and industrial construction. Figure 2 below is an example of plasma cutting of metal:
Figure 2: Plasma Cutting of Metal - Image Credit: Shutterstock/SviatlanaLaza
Compared to laser cutting, plasma cutting has the advantage in:
- Cost: Laser cutters are typically more expensive to operate than plasma cutters.
- Thicker Plates: In general, plasma cutters are able to cut thicker plates (up to 38 mm) compared to laser cutters that can cut 12.7 mm thick aluminum, 19 mm thick stainless steel, and 25.4 mm thick steel.
- Low Maintenance: Plasma technologies require significantly less maintenance than laser cutters.
Plasma cutting has some disadvantages compared to laser cutting. These include:
- Larger Kerf: The larger kerf size of plasma cutting means that it is less accurate, and therefore is more limited compared to laser cutting.
- Limited Functionality: Plasma cutting does not offer engraving functionality as laser cutting machines do.
- Radiation: Plasma cutters, unlike laser cutters, create radiation. This necessitates the use of protective equipment, including goggles or glasses for workers.
- Limited Materials: Plasma cutters are limited to use on electrically conductive materials.
Although this is changing as technology advances, the majority of laser equipment is not powerful enough to cut materials that are thicker than 19 mm. Laser cutters can cut 12.7 mm thick aluminum, 19 mm thick stainless steel, and 25.4 thick steel. Plasma cutters, on the other hand, can cut through metal plates up to an inch and a half thick.
The cutting surface of laser cutters is without burrs, smooth, and has good cut quality. Plasma cutters, on the other hand, are known to have poor perpendicularity. They create cuts with more cutting slag that needs to be removed by grinding, thus increasing the labor cost. Overall, laser cutters have a better surface finish, making laser cutting ideal for intricate designs.
Laser cutters produce cuts with very narrow slot widths of approximately ±0.15 mm and high precision of 0.01 mm or less. Plasma cutters, on the other hand, have a larger slot width (larger than 3.8 mm) and a precision of about 0.5-1 mm. The precision of both these cutters is influenced by the thickness of the material that is being cut. More power will be required for thicker materials, which leads to larger nozzles and a higher electrical current and results in a larger cut width.
The main alternatives to laser and plasma cutting technologies are:
- Water Jet Cutting: On thicker plates, water jet cutting is more cost-effective than plasma or laser cutting. However, plasma and laser cutters are better for quick, tiny cuts.
- Oxy-Fuel Cutting: Oxy-fuel cutting is mainly used to cut thick metals and has relatively low accuracy.
- Wire EDM (Electrical Discharge Machining): Wire EDM is an accurate but very slow cutting technique.
This article presented the differences between laser cutting and plasma cutting, explained what they are, and discussed how each is used in manufacturing. To learn more about laser cutting and plasma cutting, contact a Xometry representative.
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