Laser Cutting

A laser cutter is a CNC machine whose “tool” is a focused beam of light: there is no cutting force, only heat. A few hundred watts of CO₂ laser cut wood, acrylic, leather and fabric in a workshop; kilowatts of fiber laser cut steel and aluminum sheet in a factory; a few watts of diode laser engrave and cut thin material at a hobby bench. The skill is in matching the wavelength to the material, finding the power and speed that melt or vaporize a narrow kerf without burning the edge, designing parts that allow for the kerf, and above all running the machine safely, because a Class 4 laser can blind and set fires. This guide takes the subject in ten pages: how lasers work and the types, materials, power-speed-focus-gas, kerf and design, engraving, files and software, machine hardware, safety, industrial metal cutting, and the cost and upkeep of a laser shop. Every worked number is computed so that you can check your own settings. The machine types, coordinates and G-code common to all CNC tools are in CNC Machining; workshop-wide safety is in Workshop Safety.

Start here: what do you need?

I need to…	Go to
understand how a laser cuts, or choose between CO₂, diode and fiber	How Laser Cutting Works and Laser Types
find out whether a material can be cut, engraved or must never be lasered	Materials, Thickness and What a Laser Can Cut
set power, speed, focus and gas, or build a test grid	Power, Speed, Focus and Assist Gas
allow for the kerf, design a press fit, a finger joint or a living hinge	Kerf, Accuracy and Designing Parts
engrave images or text, choose a resolution, or use a rotary	Engraving, Marking and Raster Work
prepare files, nest parts, order the cuts or tune the controller	Files, Software and Toolpaths
choose, align or cool a machine, or size the extraction	Machine Hardware: Optics, Motion and Cooling
keep eyes safe, choose goggles, prevent fires or handle fumes	Laser Safety, Fire and Fumes
cut metal sheet with a fiber laser, choose a gas or cost the cut	Industrial Laser Cutting: Metals, Gas and Process
price jobs, plan maintenance, or troubleshoot a laser	Running a Laser Shop: Costs, Maintenance and Troubleshooting

A suggested order

Start with Laser Safety, Fire and Fumes if you are about to use a laser at all, then How Laser Cutting Works and Laser Types and Materials, Thickness and What a Laser Can Cut. Power, Speed, Focus and Assist Gas, Kerf, Accuracy and Designing Parts and Engraving, Marking and Raster Work are the working skills; Files, Software and Toolpaths and Machine Hardware: Optics, Motion and Cooling explain the machine and the files; Industrial Laser Cutting: Metals, Gas and Process and Running a Laser Shop: Costs, Maintenance and Troubleshooting cover production and a working shop.

1. How Laser Cutting Works and Laser Types: CO2, diode, fiber and UV lasers, wavelength and absorption, the focused beam, spot size and depth of focus, and the machine types.
2. Materials, Thickness and What a Laser Can Cut: Which materials cut, engrave or must never be lasered, an energy-balance estimate of cutting speed, and power against thickness.
3. Power, Speed, Focus and Assist Gas: Line energy, test grids, focus and depth of field, pulse settings, air assist and gases, and finding settings that work.
4. Kerf, Accuracy and Designing Parts: Kerf and its compensation, taper, press fits and finger joints, living hinges, minimum features and heat effects.
5. Engraving, Marking and Raster Work: Raster engraving, line spacing and DPI, overscan and time, depth, photographs and dithering, rotary work and galvo marking.
6. Files, Software and Toolpaths: Vector and raster files, layers and colors, scale, nesting and yield, cut order and lead-ins, G-code and controller settings.
7. Machine Hardware: Optics, Motion and Cooling: Tubes and sources, mirrors and lenses, alignment, belts and steps, water cooling, air assist, extraction and power supplies.
8. Laser Safety, Fire and Fumes: Laser classes, eye protection and optical density, the nominal ocular hazard distance, enclosure and interlocks, fire and fume extraction.
9. Industrial Laser Cutting: Metals, Gas and Process: Fiber cutting of steel, stainless and aluminum, oxygen and nitrogen, pierce, nozzle and standoff, quality, nesting and gas cost.
10. Running a Laser Shop: Costs, Maintenance and Troubleshooting: Machine-hour cost and job pricing, consumables and tube life, cleaning and alignment schedules, and a troubleshooting table.

Which laser for which job?

Laser	Wavelength	Typical power	Good for	Limits
Diode (blue)	About 450 nm	5–40 W optical	Engraving wood, leather, paper; cutting thin wood and dark acrylic	Clear and blue acrylic pass the light; slow cutting
CO₂	10.6 µm (far infrared)	40–150 W (hobby and small shop); up to several kW industrial	Cutting and engraving wood, acrylic, leather, paper, fabric; marks glass	Does not cut bare metal; large tube and optics
Fiber	1.06 µm (near infrared)	20–100 W marking; 1–30 kW cutting	Marking and cutting metals	Expensive; not suited to clear plastics or wood
Ultraviolet (UV)	355 nm	3–20 W	Fine marking of glass, plastics, silicon without heating	Slow for cutting; cost

Quick reference: formulas and rules

Topic	Formula or rule	Page
Line energy	E = P ÷ v (J/mm)	Power, Speed, Focus and Assist Gas
Power density	P ÷ spot area	How Laser Cutting Works and Laser Types
Spot size	d = 4 M² λ f ÷ (π D)	How Laser Cutting Works and Laser Types
Depth of focus	2 zR = 2π w₀² ÷ (M² λ)	How Laser Cutting Works and Laser Types
Kerf compensation	offset each path by half the kerf	Kerf, Accuracy and Designing Parts
Cutting time	t = length ÷ speed + pierces × tpierce	Files, Software and Toolpaths
Cooling water	ΔT = Pheat ÷ (ρ c Q)	Machine Hardware: Optics, Motion and Cooling
Goggle density	OD = log₁₀(E ÷ MPE)	Laser Safety, Fire and Fumes
Cutting speed (thick sheet)	falls steeply with thickness; ∝ P ÷ t1.5 as a model	Industrial Laser Cutting: Metals, Gas and Process
Machine-hour cost	depreciation + power + consumables + labor	Running a Laser Shop: Costs, Maintenance and Troubleshooting

Related guides and tools

• CNC Machining: machine types, coordinates, G-code, toolpaths and the router and mill that complement a laser.
• Workshop Safety: PPE, fire, fumes and electrical safety around the machine.
• Fits and Tolerances: clearances and press fits for laser-cut joints.
• Industrial Robotics: robot-loaded and robot-held laser cells.
• Structures and Strength of Materials: strength of sheet parts and joints.
• Electronics Fundamentals: the power supplies and drivers inside the machine.

Safety first

• Laser light is dangerous. Open-frame diode and CO₂ lasers are Class 4: even a reflection can cause permanent eye damage. Use an enclosed machine with an interlocked lid; for open machines wear goggles rated for your laser’s exact wavelength (see Laser Safety, Fire and Fumes).
• Fire. Never leave a running laser unattended, keep air assist on, keep an extinguisher at hand and the bed clear of offcuts.
• Never cut PVC, vinyl or anything containing chlorine, nor polycarbonate, ABS, fiberglass or unknown plastics: they give toxic and corrosive fumes. Extract the fumes outdoors or through a proper filter.
• Settings in this guide are starting points. Test on scrap, follow your machine maker’s instructions and the rules where you work.

FAQ

Which is better for me, a diode, CO₂ or fiber laser?

Diode for a low-cost start with thin wood and engraving; CO₂ for cutting wood, acrylic and leather in a small shop, with the widest material range; fiber for metals. Clear acrylic and glass need CO₂; metals need fiber. See How Laser Cutting Works and Laser Types.

Why are my parts not the size I drew?

Check the steps per mm, compensate for the kerf (half on each side of the path), and allow for material movement and taper. See Kerf, Accuracy and Designing Parts.

Is it safe to use a laser at home?

Only if it is enclosed or the room is controlled, you wear wavelength-rated eye protection, you extract the fumes, you never leave it running, and you cut only approved materials. If you cannot meet all of those, do not run it. See Laser Safety, Fire and Fumes.

Where did the old Laser Cutting sections go?

All of them are in this guide with much more depth: the laser types, power and speed, kerf and fits, engraving, safety and troubleshooting each have their own pages.

References

• IEC 60825-1, Safety of laser products: equipment classification and requirements; ANSI Z136.1, Safe use of lasers; IEC 60825-14 (user’s guide).
• Steen, W. M. and Mazumder, J., Laser Material Processing, Springer; Powell, J., CO₂ Laser Cutting, Springer; Kalpakjian, S. and Schmid, S., Manufacturing Engineering and Technology, Pearson.
• Laser and machine makers’ material guides (Trotec, Epilog, Universal, Glowforge, Trumpf, Bystronic), for starting values.

Last reviewed: October 2026. Machine behavior and settings differ widely: test on scrap, and follow your machine maker’s safety instructions and your local rules for lasers and machinery.