Laser Cutting Design Guide

Our 3kW fibre laser achieves ±0.1mm cutting accuracy on individual features and ±0.1mm positional accuracy between features on the same part. This is achievable on all materials and thicknesses within our cutting range.

Kerf width (the material removed by the laser beam) varies from approximately 0.15mm on thin sheet to 0.3mm on thick plate. Our CAD system automatically compensates for kerf so that the finished part matches your drawing dimensions. You do not need to add kerf compensation to your DXF files.

For tighter tolerances than ±0.1mm, secondary CNC machining can be added after laser cutting. Our CNC machining achieves ±0.05mm on turned features.

Minimum feature sizes in laser cutting are driven by material thickness. Thicker material concentrates more heat in smaller areas, so features need to be proportionally larger. All rules below are expressed relative to the material thickness (T).

Quick reference: minimum features by thickness

Min Flange = minimum bend flange length (2T + bend radius + clearance for die opening). Based on standard V-die tooling.

Material choice affects cutting speed, edge quality, cost and downstream processing. Here is what we cut on our 3kW fibre laser, with the assist gas used and typical edge finish.

Oxygen vs nitrogen assist gas

Oxygen (O2) is used for mild steel, galvanised and corten. It creates an exothermic reaction that helps cut through thicker material but leaves a dark oxide layer on the cut edge. This oxide is cosmetic only and does not affect structural integrity.

Nitrogen (N2) is used for stainless steel, aluminium, copper and brass. It produces a clean, oxide-free edge with no discolouration. N2 cutting is faster on thin stainless and aluminium but consumes more gas, which increases cost slightly.

Press brake bending adds a third dimension to laser cut flat parts. Designing bends correctly avoids cracking, distortion and dimensional errors.

Minimum bend radius by material

The inside bend radius (R) is expressed as a multiple of the material thickness (T). Going below the minimum risks cracking on the outer surface of the bend.

Minimum flange length

The flange is the flat section beyond the bend. If the flange is too short, the press brake die cannot grip the material properly. As a rule of thumb: minimum flange ≥ 2T + bend radius + 2mm clearance. Use our K-Factor Calculator to calculate exact flat pattern lengths including bend allowance.

Hole-to-bend distance

Keep holes, slots and cutouts at least 2T + R (twice the thickness plus the bend radius) away from any bend line. Features closer than this will distort when the metal bends, turning round holes into ovals and pulling slot edges out of alignment.

Bend relief

Where a bend line meets the edge of the part or another feature, add a bend relief cut. This is a small slot (width ≥ T, length ≥ T + R) at each end of the bend line. Without bend relief, the material tears at the junction.

K-factor and flat pattern

The K-factor determines how much material is consumed by each bend. For mild steel we use K = 0.44 as default. Our system automatically calculates flat patterns from STEP files using K-factor bend deduction. If you are designing in 2D (DXF), you need to account for bend allowance yourself. Use our Bend Allowance Calculator or refer to the formulas: BA = π/180 × angle × (R + K × T).

Accepted file formats

DXF preparation tips

• ✓Draw at 1:1 scale in millimetres. Our system reads the file as-is.
• ✓Close all contours. Open paths will be flagged as warnings.
• ✓Delete unused layers, dimensions and text before exporting.
• ✓Ensure there are no overlapping or duplicate lines (common in imported files).
• ✗Do not add kerf compensation — we handle this automatically.
• ✗Do not include bend lines in a DXF. Use STEP format for parts with bends.

Not sure if your file is ready? Use our free DXF Viewer to check your file in the browser before uploading.

Laser cutting cost is driven by four factors: material, cut time, piercing, and handling. Here is how to optimise each.

Material

• Use the thinnest material that meets your strength requirements. Cutting speed roughly doubles when you halve the thickness.
• Mild steel is the cheapest sheet metal by far (~$3/kg vs ~$9–12/kg for stainless or aluminium).
• Consider whether you actually need stainless. For indoor brackets, mild steel with paint or powder coat is usually adequate.

Cut length

• Simpler outlines cut faster. Round corners instead of sharp corners (the laser must decelerate at sharp corners).
• Replace decorative patterns with functional geometry where appearance is not critical.
• Rectangular parts nest more efficiently on a sheet than complex shapes, reducing material waste.

Piercing

• Each hole or internal cutout requires a separate pierce. Pierce time increases dramatically with material thickness (0.2s for 1mm, up to 25s for 16mm).
• Combine small closely-spaced holes into a single slot where functionally equivalent.
• In thick material (8mm+), piercing can cost more than cutting. Minimise internal cutouts.

Quantity

• Batch pricing spreads fixed costs (setup, handling) across more parts. Per-unit cost drops significantly at 5, 10, 25+ parts.
• Parts that nest efficiently together (same material and thickness) benefit from shared sheet usage.