A dependable laser cutting service in India should tell you three things before you send a drawing: which materials it can cut, how thick it goes on each, and the tolerance it will actually hold on the finished edge. At our AS9100-certified facility in Satellite, Ahmedabad, we run a 3 kW fibre laser that cuts mild steel up to roughly 20 mm, stainless to about 12 mm, and aluminium to around 8 mm — with machine positioning accuracy of ±0.05 mm and part tolerances that tighten as the sheet gets thinner. This guide covers the material-by-material limits, the difference between kerf and tolerance, assist-gas selection, and the design details that decide whether a part comes off the bed ready to weld or ready for rework. No minimum order quantity, engineer-reviewed quotes in 24 hours, and full material traceability on every job.
Key Takeaways
- Thickness envelope: a 3 kW fibre laser cuts ~20 mm mild steel, ~12 mm stainless, ~8 mm aluminium, ~4–5 mm copper and brass.
- Kerf is not tolerance: positioning is ±0.05 mm, but part tolerance runs ±0.1 mm on thin sheet, widening to ±0.5 mm on thick plate.
- Gas defines the edge: oxygen for fast, thick mild steel; nitrogen for clean, weld-ready stainless and aluminium.
- Edge quality is a standard: ISO 9013 grades perpendicularity and roughness into ranges 1–5.
- Commercially flexible: no MOQ, 3–5 day lead time, CMM-verified reports and full traceability.
Which materials and thicknesses our fibre laser handles
A fibre laser cuts by focusing an intense beam that melts and vaporises metal while an assist gas blows the melt out of the kerf. The 3 kW source in our Ahmedabad shop is tuned for sheet and plate, so the practical ceiling depends on the metal's reflectivity and thermal conductivity. Mild steel (IS 2062, S235JR, EN 10025 grades) cuts cleanest and thickest — up to about 20 mm with oxygen assist. Stainless steels (304, 316L) top out near 12 mm, because nitrogen cutting needs more power to keep the edge bright and oxide-free. Aluminium alloys (5052, 6061) reach roughly 8 mm: they conduct heat away fast and reflect more of the beam, so thicker plate turns slow and dross-prone. Copper and brass are hardest — high reflectivity caps clean cutting near 4–5 mm.
When comparing any laser cutting service in India, those numbers matter more than headline wattage, because a well-tuned 3 kW machine with the right optics and gas pressure out-cuts a poorly set-up 4 kW one. If your part sits inside these envelopes, our fibre laser cutting service holds tight edges and repeatable geometry batch after batch.
Kerf, tolerance and edge quality — three numbers people confuse
Buyers often collapse three separate specifications into one word — "accuracy" — and then get surprised. Kerf is the width of material the beam removes, typically 0.1–0.4 mm depending on thickness and focus; the CAM software offsets the toolpath by half the kerf so your part lands on nominal. Tolerance is how close a finished feature sits to the drawing dimension: our machine positions to ±0.05 mm, but real part tolerance depends on thickness and thermal distortion — expect ±0.1 mm on sheet under 3 mm, opening to ±0.2–0.5 mm on 15–20 mm plate as heat input grows. Edge quality is a third axis entirely: perpendicularity and roughness down the cut face.
ISO 9013 classifies thermal cuts by perpendicularity tolerance (u) and mean roughness (Rz5) into ranges 1–5; a well-tuned fibre laser on 6 mm mild steel routinely holds Range 1–2, roughly u ≤ 0.15 mm.
If you need a datum face guaranteed square for welding or machining, say so up front — we may leave grind stock or flag a secondary op. Specifying a realistic band keeps cost down; over-tolerancing a laser edge just invites needless finishing.
Assist gas: oxygen versus nitrogen
Assist gas is not a detail — it defines the edge. Two gases cover almost everything:
- Oxygen (O₂): an exothermic reaction adds energy, so it cuts mild steel faster and thicker — but leaves a thin oxide layer that must be removed before powder coating or paint.
- Nitrogen (N₂): an inert, high-pressure gas that produces a clean, oxide-free edge on stainless and aluminium, ready to weld or coat — at the cost of speed and higher gas consumption.
For a structural mild-steel bracket bound for hot-dip galvanising, oxygen is the economical call. For a 316L medical tray we also process under our ISO 13485 system, nitrogen is mandatory — an oxidised edge would fail downstream passivation. A Rajkot-based OEM once sent us 3 mm 304 parts cut elsewhere with oxygen; the discoloured edges rusted in transit, and re-cutting with nitrogen fixed it permanently. We pick gas per material and per downstream process, not per machine default — which is why our edges arrive ready for the next operation rather than the wire brush.
Material and thickness quick-reference
The table below is the working envelope we quote against. Treat each maximum as the point where clean, repeatable edges stop — we can push a millimetre further on a one-off, but batch quality drops.
| Material | Max thickness (3 kW) | Assist gas | Typical edge |
|---|---|---|---|
| Mild steel (IS 2062, S235JR) | ~20 mm | Oxygen | Oxide edge, square |
| Stainless 304 / 316L | ~12 mm | Nitrogen | Bright, oxide-free |
| Aluminium 5052 / 6061 | ~8 mm | Nitrogen | Matte, minor burr |
| Brass | ~5 mm | Nitrogen | Reflective, moderate |
| Copper | ~4 mm | Nitrogen | Reflective, hardest |
Anything beyond these is better served by plasma, waterjet, or a design change — and we will tell you so during the quote rather than ship a ragged edge.
Design rules for laser-ready parts
A clean DXF or STEP cuts faster and cheaper. Follow these before sending artwork to any laser cutting service:
- Minimum hole diameter ≥ material thickness. A 2 mm hole in 3 mm plate tapers and slags; keep holes at or above sheet thickness for straight walls.
- Slot width ≥ thickness, and keep 3–4× thickness between features so heat doesn't warp thin webs.
- Give internal corners a small radius (≥ 0.5 mm) — a laser cannot cut a true zero-radius inside corner anyway.
- Avoid engraving or text under 2 mm stroke; fine detail simply fills with dross.
- Send vectors, not rasters — closed polylines in DXF, or a STEP for 3D and bend context.
If the part will be folded after cutting, mark bend lines on a separate layer and respect the bend-relief geometry so the blank flows straight into forming. Cutting and bending are one continuous workflow in our shop, so a file that respects both saves a full iteration cycle.
No MOQ, nesting and turnaround
Two commercial realities shape a laser job as much as the physics. First, nesting: we arrange parts to maximise sheet yield, so a full nest of related parts costs far less per piece than scattered singles. Second, there is no minimum order quantity — a lone prototype bracket and a 500-piece run are equally welcome, which suits the ISRO-, DRDO- and iDEX-linked prototyping cycles we support, where the first article matters more than volume.
Standard lead time is 3–5 working days, and an engineer reviews every quote within 24 hours — not a black box that auto-prices and ignores manufacturability. When a laser-cut blank needs folding it moves straight to our 160-tonne, 3200 mm press brake; see how we hold those angles in our CNC press-brake bending and sheet-metal service. Keeping cutting and forming under one AS9100 roof means one traceability trail, one dimensional report, and no finger-pointing between vendors if a dimension drifts. That single-source control is what most buyers searching for a laser cutting service in India are really after.
Frequently Asked Questions
What is the thickest steel your laser can cut?
Our 3 kW fibre laser cuts mild steel up to about 20 mm with oxygen, stainless to roughly 12 mm, and aluminium to around 8 mm with nitrogen. Beyond those, squareness and edge quality degrade, so we would recommend plasma, waterjet, or a design change instead.
What tolerance can I expect on a laser-cut part?
The machine positions to ±0.05 mm, but hold-able part tolerance depends on thickness — about ±0.1 mm under 3 mm, widening to ±0.2–0.5 mm on 15–20 mm plate. For critical features we supply a CMM-verified dimensional report.
Do you have a minimum order quantity?
No. We cut single prototypes and production batches alike, with the same 24-hour engineer-reviewed quote and full material traceability. Nesting a family of parts on one sheet lowers the per-piece cost considerably.
Which file format should I send?
A DXF with closed polylines is ideal for pure 2D cutting; a STEP file is better if the part will be bent, since it carries thickness and bend context. Avoid rasterised images — they cannot be toolpathed accurately.
Whether you are prototyping a single aerospace bracket or scheduling a production nest of enclosures, the fastest way to real numbers is to send the drawing and let an engineer scope it against the machine's true envelope. Upload your DXF or STEP, tell us the material, thickness and finish, and we will return cut cost, lead time and any DFM flags. Request a 24-hour quote.