Laser Cutting
Also: fiber laser cutting, CO2 laser cutting, laser profiling, laser cut parts, sheet metal laser cutting, laser cutting service, flat laser cutting, tube laser cutting
Laser cutting profiles sheet and plate with a focused beam and assist gas: fiber lasers cut steel to 25 mm and stainless or aluminum to 20 mm at ±0.1 mm.
860 laser cutting companies in the Noramark directory
A beam focused to a 0.1-0.3 mm spot melts the metal and a coaxial jet of assist gas blows the melt out of the kerf as the cutting head traverses under CNC. Fiber lasers (1.07 µm wavelength, solid state, 2-12 kW in most job shops and 20-30 kW at the top end) have replaced CO2 (10.6 µm, 2-6 kW) for metal: the shorter wavelength couples better into reflective aluminum, brass and copper, cuts thin sheet two to three times faster and costs less to run. CO2 keeps a niche in non-metals such as acrylic and wood, and gives a marginally smoother edge on thick mild steel.
The assist gas is a choice the buyer should make. Oxygen on carbon steel adds heat from the exothermic reaction, cuts thicker plate with less power and leaves a thin dark oxide on the edge. Nitrogen on stainless, aluminum and on carbon steel when the edge matters gives a bright, oxide-free edge that welds and powder coats cleanly, at the cost of more laser power and more gas. Compressed air is the cheap middle ground on thin sheet. Cut speed runs tens of meters a minute in thin sheet and about 1-2 m/min at 20 mm, holes come out close to round down to about the material thickness, and the heat-affected zone is 0.1-0.5 mm.
Job shops routinely cut carbon steel to 25 mm (1") with oxygen, stainless to 20-25 mm and aluminum to 16-20 mm with nitrogen; 12-20 kW machines push into 30-40 mm, but edge quality and cost per meter fall away and plasma (carbon steel) or waterjet usually wins above 25 mm. Thick material shows a slight taper and striations, oxygen-cut edges need cleaning before paint, medium-carbon and alloy steels harden at the edge, and thick aluminum drags a dross line. PVC releases chlorine gas, polycarbonate chars, and fiberglass and carbon fiber delaminate and fume: none of them belong on a laser.
At a glance
| Typical tolerances | Standard ±0.1 mm (±0.004") on parts under 6 mm (1/4") thick; ±0.05 mm (±0.002") with care on thin sheet from a calibrated machine; ±0.25 mm (±0.010") on plate over 12 mm (1/2"). Holes larger than the thickness hold ±0.05-0.1 mm on diameter. Edge perpendicularity is within 0.05-0.1 mm on sheet and 0.2-0.4 mm (a slight taper) on 20 mm plate. Long thin parts grow 0.2-0.3 mm per meter during a hot nest, so tolerance them accordingly. |
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| Size limits | Standard beds take 1,500 x 3,000 mm (5 x 10 ft) sheet, many shops 2,000 x 4,000 mm (6.5 x 13 ft), and some 2,000 x 6,000 mm or larger. Thickness with a 6-12 kW fiber laser: carbon steel to 25 mm (1"), stainless to 20-25 mm (3/4-1"), aluminum to 16-20 mm (5/8-3/4"), brass and copper to 6-8 mm (1/4-5/16"); the highest-power machines reach 30-40 mm in steel. Tube lasers take round tube to 150-250 mm (6-10") diameter in 6-12 m lengths. The smallest hole is about one material thickness and the narrowest slot about 1-1.5 thicknesses. |
| Surface finish | Cut edge 1.6-6.3 µm Ra (63-250 µin): finer on thin sheet, striated on thick plate. Nitrogen-cut edges are bright and oxide-free; oxygen-cut carbon steel edges carry a thin dark oxide that should be removed before powder coating or critical welding. A small burr or dross line on the underside, heavier on thick aluminum and oxygen cuts, is removed by deburring or a timesaver. The heat-affected zone is 0.1-0.5 mm (0.004-0.020") and the edge hardens on medium-carbon and alloy steels. |
| Lead time | Flat parts in 1-5 business days, with many shops quoting same-week for stocked sheet; production in 1-3 weeks. Add a week for forming, welding, powder coating or plating downstream. Material availability sets lead time more than cutting time. |
Typical of U.S. job shops; confirm with the shop for your part.
Materials
Carbon steel in every form: hot-rolled A36 and A572 plate, cold-rolled sheet, 1018, and 4130 for aerospace and motorsport. Stainless 304 and 316 cut cleanly with nitrogen. Aluminum 5052, 6061 and 5083 cut well on fiber, with a dross line on thick plate. Brass and copper cut on fiber to about 6-8 mm (1/4-5/16"); titanium cuts with argon or nitrogen, with nitrogen leaving an embrittled edge that critical parts grind off. Galvanized sheet cuts fine but the zinc fumes need extraction. Inconel and other nickel alloys cut slowly and cleanly. Acrylic, wood and some plastics cut on CO2 only; PVC, polycarbonate and fiber-reinforced laminates should not be laser cut.
What drives the cost
- Cut length and pierces: machine time is the path length plus a pierce per contour, at a speed set by thickness and material
- Thickness and material: 20 mm stainless cuts at a fraction of the speed of 2 mm and uses far more nitrogen
- Assist gas: nitrogen cutting costs more per meter than oxygen or air, especially on thick plate
- Material cost and nest yield: the sheet is a large share of the price on thick plate and stainless, so nesting and remnant use matter
- Quantity: setup is minutes, so unit cost falls quickly but the cut still takes its time per part
- Secondary operations: deburring, tapping, countersinking, forming, hardware insertion and finishing
- Tolerances tighter than ±0.1 mm (±0.004") or edge requirements that force slower speeds or a machining step
When to use it
- Flat sheet and plate parts from 0.5 to 25 mm (0.020-1") thick in steel, stainless and aluminum
- Prototypes through production: same day for a handful of brackets, thousands a week from nests
- Blanks for press-brake forming and weldments, with holes, slots and tabs already cut
- Parts that need a clean, square, near-burr-free edge and holes down to the material thickness
- Tube and structural profiles with cutouts, copes and end preparations
When not to
- Plate thicker than 25 mm (1"): plasma for carbon steel and waterjet for everything else cost less
- Materials that reflect or burn: thick copper and brass on low-power machines, PVC (chlorine gas), polycarbonate (chars), fiberglass and carbon fiber (fumes and delamination)
- Heat-sensitive or pre-hardened parts, where the heat-affected zone changes hardness or warps the part: waterjet or wire EDM
- Tolerances below ±0.05 mm (±0.002") or machined-quality edges: cut oversize and finish by machining or wire EDM
Design tips
- Keep holes at least as large as the material thickness, ideally 1.2 times, and slots at least 1.5 times; pierce smaller holes undersize and drill or tap them afterwards.
- Keep features at least one thickness from an edge and from each other so the heat does not burn through the web.
- Specify the assist gas when the edge matters: nitrogen for stainless, aluminum and any edge to be powder coated or welded; oxygen is fine for structural carbon steel that gets painted.
- Add a deburr and edge-condition note; a laser edge is sharp enough to cut hands.
- Design for bending in the same shop: bend reliefs, minimum flange lengths and hole-to-bend distances belong in the flat pattern.
- Send a 1:1 DXF of the flat pattern plus a PDF with thickness, material spec, quantity and finish; add a STEP for formed parts.
- Use stock gauges and common alloys: 3 mm 5052 is on the shelf, 3.5 mm 6061 sheet is not.
- For precise holes and bores, ask the shop to pierce undersize and finish on a mill.
Laser Cutting by material
Frequently asked questions
- How thick can a fiber laser cut steel?
- A 6-12 kW fiber laser at a job shop cuts carbon steel to 25 mm (1") with oxygen assist, stainless to 20-25 mm and aluminum to 16-20 mm with nitrogen. The highest-power machines, 15-30 kW, reach 30-40 mm in steel, but above 25 mm the edge gets rougher and plasma or waterjet is usually cheaper.
- Fiber laser or CO2 laser?
- Fiber for metal: it cuts thin sheet two to three times faster, handles reflective aluminum, brass and copper, and costs less to run, which is why nearly every new metal-cutting laser is fiber. CO2 remains the choice for acrylic, wood and other non-metals, and a few shops keep one for a smoother edge on thick mild steel.
- Nitrogen or oxygen for laser cutting?
- Oxygen on carbon steel: cheaper, cuts thicker with less power, leaves a thin oxide edge that paints fine but should be cleaned before powder coating or critical welds. Nitrogen on stainless and aluminum, and on carbon steel when a bright oxide-free edge is needed: more power, more gas, cleaner edge. Air for thin sheet on a budget.
- What tolerance can laser cutting hold?
- ±0.1 mm (±0.004") on sheet under 6 mm is standard and ±0.05 mm (±0.002") is achievable with care on thin material. Thick plate loosens to about ±0.25 mm (±0.010") and carries a slight taper. Thermal growth on long parts and the edge condition matter more than the machine's positioning accuracy.
- What is the kerf of a laser cutter?
- The width of material the beam removes: about 0.1-0.2 mm (0.004-0.008") on thin sheet and 0.3-0.5 mm (0.012-0.020") on thick plate with a fiber laser. The program offsets the path by half the kerf, so a good shop delivers the drawing dimension, not the dimension minus the kerf.
