Laser cutting and sheet metal bending: prices, thicknesses and good practice

There is no “ideal” cutting process: each one suits a particular combination of material, thickness, accuracy and quantity. A sheet metal and cutting workshop often masters several and picks the best compromise between cut quality and cost.

Fibre laser

This is the most widespread process for thin to medium sheet. Its wavelength (close to 1 µm) is well absorbed by metals, including reflective alloys such as aluminium, brass or copper on suitable machines. It is fast on thin gauges, accurate, and leaves clean edges with a reduced heat-affected zone.

CO2 laser

Older technology (10.6 µm), still used for some thick plate when edge appearance matters, and for non-metallic materials (acrylic, wood, some plastics) that a fibre laser handles poorly. On thin sheet metal, fibre is generally faster and cheaper.

Plasma

The plasma arc cuts all conductive metals and becomes competitive on heavy thicknesses, where a laser is slower or more expensive. Accuracy is lower (slight bevel, wider heat zone): it suits boilermaking and plate fabrication and structural parts that will be welded or reworked.

Waterjet

A very high-pressure water jet loaded with abrasive cuts almost any material (metals, stone, glass, composites) without heating, and therefore without thermal distortion. The trade-off is that it is slower, with possible slight taper. It is worth it for heat-sensitive materials, heavy thicknesses or difficult alloys.

Punching

The punch press strikes the sheet with tooling. On large runs of thin sheet with many holes, formed features (louvres, embossings) or formed threads, it can be very economical. Complex contours are still simpler with a laser, and many workshops combine the two.

Limits depend on machine power, assist gas and the edge quality required. This table gives common orders of magnitude for fibre laser cutting. They are indicative: confirm them with the workshop that will make your parts.

Beyond that, you switch to plasma, oxy-fuel cutting or waterjet. Sheets are supplied in standard formats (for example 3,000 × 1,500 mm): how your parts are laid out on these formats determines the scrap.

The price of a sheet metal part adds up material, machine time and labour, plus setup and finishing. Here is what explains most of the gap between two quotes.

• Material. Type (stainless steel and aluminium cost more per kilo than mild steel), thickness, any material certificate. You also pay for scrap: the whole sheet is consumed, not just the weight of the part.
• Thickness. Cutting speed drops sharply as thickness increases: machine time per metre of cut grows faster than the thickness.
• Cut length. The longer the outline and internal cut-outs, the longer the machine runs. A part with many openings costs more than a solid plate of the same dimensions.
• Number of pierces. Every hole or internal cut-out starts with a pierce before the beam follows the contour. On heavy thicknesses each pierce takes time: hundreds of small holes quickly weigh on the price.
• Bends. Number of bends, length, angles, tooling: each bend requires handling and a press brake adjustment. A part with many bends is priced mainly on bending time.
• Additional operations. Deburring, tapping, insertion of fasteners, welding, surface treatment, dimensional inspection.
• Quantities. Programming and setup are spread over the run: the unit price falls markedly between a single piece and a few dozen, then more gradually.

Nesting means laying out the parts on the sheet to minimise scrap. Its utilisation rate bears directly on the price, especially in stainless steel or aluminium. The workshop’s software does the calculation, but you can help:

• by favouring outlines that fit together rather than very irregular shapes;
• by grouping several references of the same material and thickness in one order, so that they share the same sheets;
• by accepting common-line cutting (two neighbouring parts share a cutting line) when the specification allows it;
• by adapting dimensions to standard formats when the design is flexible.

Other levers

• Reduce variety: a single bend radius and a few standard hole diameters limit tool changes.
• Tighten only functional dimensions: see the guide on ISO 2768 general tolerances.
• Ask for several quantities: quoting 10, 50 and 200 parts reveals the price curve.
• Accept an equivalent grade and allow a reasonable lead time: urgency costs extra.

A part drawn without thinking about bending may be impossible to make or may require special tooling. The values below (t is the thickness) are orders of magnitude for common sheet: they vary with tooling, material and machine, and the workshop has the final say.

Grain direction, springback and tolerances

For hard alloys, it is better to bend perpendicular to the rolling direction. After bending, the material “springs back” slightly (springback): the workshop compensates by adjusting the angle. On thin sheet, you can commonly expect around ±0.1 to ±0.2 mm for laser cutting and wider tolerances on bent dimensions, to be confirmed with the workshop. Tighten only the dimensions that require it.

Unfolding

The flat pattern (the part laid flat) depends on the material, thickness, radius and tooling. Unless you master this calculation, send the bent part in 3D with its functional dimensions: the workshop calculates the unfolding.

A badly prepared DXF wastes time and causes cutting errors. A few rules are enough:

• Scale 1:1, units in millimetres, flat 2D geometry.
• Closed outlines, with no duplicate or overlapping lines (the machine would cut twice) and no stray micro-segments.
• Simple curves: replace splines with polylines or arcs, and explode blocks.
• Separate layers for cutting, bend lines and engraving, with a legend.
• Nothing but geometry: no dimensions, text or title block in the cutting drawing.
• One part per file, named with its reference, revision index, material and thickness.

A complete request gets you faster, comparable quotes. State the material, grade and thickness (or “equivalent accepted”), quantities, files (DXF, PDF drawing, STEP), finishes (see the surface treatment expertise page), critical dimensions, any material certificate, the lead time and the delivery location.

On Meaflow, posting a request is free and commission-free: you receive quotes from several suppliers, can compare them, ask your questions and exchange messages before choosing. To structure your request, use our guide to the manufacturing specification.