How material thickness changes laser cutting price

Thickness raises a laser-cut part price twice, and buyers usually argue about the smaller half. The first half is mass: a 6 mm panel holds five times the steel of a 1.2 mm panel of the same area, and steel is bought by the kilogram. The second half is machine time: the cut slows from about 24 m/min at 1.2 mm to 4 m/min at 6 mm, so the minutes rise too. Put a number on both and the argument changes shape.

This is how material thickness changes laser cutting price in practice: the price climbs almost in step with the mass, the machine-time share stays small, and the lever worth pulling is gauge and nesting rather than the cutting rate.

Which half of the price does thickness actually move?

Mass, in almost every case. On a standard 0.22 m² enclosure panel, material is 96–98% of the part price at 1.2 mm, 3 mm and 6 mm. Machine time rises faster than thickness, but it starts from a base too small to matter.

The cut speed falls faster than thickness grows. From 1 mm to 12 mm, thickness multiplies by 12 and planning cut speed divides by 20, so the time per metre of cut multiplies by 20. That is an exponent of about 1.2:

ln(20) / ln(12) = 3.00 / 2.48 = 1.21

Across the 1–12 mm range the exponent sits between 1.1 and 1.3, depending on material and assist gas. Mass, by contrast, is exactly linear: double the thickness, double the kilograms. Since material carries nearly the whole price, the part price follows the linear term.

Speeds are planning values at 65% of the straight-line peak, for mild steel and CRCA. Mass assumes 7.85 g/cm³.

What does a 0.22 m² panel cost at 1.2, 3 and 6 mm?

The worked example below uses planning inputs only: material at ₹62/kg, machine at ₹30/min, 80% nest utilisation, 1,200 mm of cut and 6 pierces. Those rates are illustrative, not quoted prices, and the reader should substitute their own.

1.2 mm. Net mass 0.22 × 1.2 × 7.85 = 2.072 kg. At 80% utilisation the sheet consumed is 2.072 / 0.8 = 2.59 kg, which is ₹160.61. Cutting is 1,200 / 24,000 = 0.05 min, plus 6 pierces at 0.25 s = 0.025 min, so 0.075 min of machine time, which is ₹2.25. Part price ≈ ₹162.86, of which material is 98.6%.

3 mm. Net mass 5.181 kg, consumed 6.476 kg, ₹401.53. Cutting is 1,200 / 10,000 = 0.12 min, plus pierces at 0.5 s each = 0.050 min, so 0.17 min, ₹5.10. Part price ≈ ₹406.63, material 98.8%.

6 mm. Net mass 10.362 kg, consumed 12.953 kg, ₹803.06. Cutting is 1,200 / 4,000 = 0.30 min, plus pierces at 1.1 s each = 0.110 min, so 0.41 min, ₹12.30. Part price ≈ ₹815.36, material 98.5%.

The ratios are 1 : 2.50 : 5.01 against a thickness ratio of 1 : 2.5 : 5. The price is the mass.

Why does cut speed fall faster than thickness rises?

Because the cut is removing a wider kerf at a lower energy density per unit volume of removed metal, and because the assist gas has further to travel to eject the melt.

Three effects stack. The kerf widens from about 0.15 mm at 2 mm to 0.8–1.2 mm at 20 mm, so each millimetre of travel removes more material. The pierce takes longer, so the non-cutting time per feature grows. And the thicker section needs more power to keep the cut through, which raises the heat input into the part and, on thin sections of the same part, the distortion.

None of that changes the price much, because the machine is not where the money is. It does change the edge. On 6 mm and above, the lower edge is rougher and the kerf tapers, so a part that needs a square functional face gets a machining operation added. That operation usually costs more than the extra cutting minute. The thickness and edge quality guide sets out what the edge looks like at each gauge.

When does machine time become the driver?

When the part is small, has a long cut length and many features. That is the geometry of a bracket or a perforated panel, not a canopy side.

Take a 0.05 m² bracket with 4,000 mm of cut and 40 pierces, at 1.5 mm (about 20 m/min, between the 1.2 and 2.0 mm rows) and at 6 mm, on the same planning rates.

1.5 mm. Net mass 0.05 × 1.5 × 7.85 = 0.589 kg, consumed 0.736 kg, ₹45.63. Cutting 4,000 / 20,000 = 0.20 min. Pierces 40 × 0.25 s = 10 s = 0.167 min. Machine time 0.367 min, ₹11.00. Part price ≈ ₹56.63, machine 19.4%.

6 mm. Net mass 2.355 kg, consumed 2.944 kg, ₹182.51. Cutting 4,000 / 4,000 = 1.0 min. Pierces 40 × 1.1 s = 44 s = 0.733 min. Machine time 1.733 min, ₹52.00. Part price ≈ ₹234.51, machine 22.2%.

The machine share rises from 19% to 22% as the gauge goes up, because the pierce time per hole multiplies by 4.4 while the mass only multiplies by 4. At 10 mm the same part runs 40 pierces at 2.5 s each, which is 1.67 minutes of piercing before a single millimetre of contour is cut. That is worth specifying: fewer, larger holes and a drill operation afterwards can be cheaper than 40 laser pierces in thick plate.

What is the cheapest way to reduce a laser-cut part price?

Three levers, and they are not equally strong. Use them in this order.

Gauge. On a 0.22 m² blank, each millimetre of thickness is 0.22 × 7.85 = 1.727 kg net, or 2.159 kg consumed at 80% yield, which is ₹133.85 per part per millimetre. Dropping from 3 mm to 2 mm therefore saves ₹133.85, about a third of the part. Dropping from 3 mm to 2.5 mm saves half that. This is the only lever that changes the price by double digits, and it is a structural decision, not a purchasing one.

Nest yield. Moving from 80% to 88% yield on the same 3 mm part takes consumed mass from 6.476 kg to 5.887 kg, a saving of 0.589 kg or ₹36.52, which is 8.9% of the part. Ten points, from 80% to 90%, saves 0.720 kg or ₹44.61, about 11%. Either is worth less than half a millimetre of gauge, but it costs nothing in design and it is available on every order. The nesting cost guide covers the layout rules.

Cut length and pierce count. On a 2 mm part, shortening the cut by 300 mm saves 0.019 min, which is 56 paise at the planning rate. On a 10 mm part the same 300 mm saves 0.15 min, ₹4.50. So the design change is worth making on thick plate and worth ignoring on thin sheet. Removing a hole from a 10 mm part saves 2.5 s of pierce, ₹1.25, which is less than the 300 mm of contour at ₹4.50.

The decision rule: below 3 mm, change the gauge or the nest; above 8 mm, change the feature count and the geometry; at every gauge, check the mill certificate thickness before accepting a price that moved without a drawing change.

How does thickness change the bending and welding cost?

It changes them faster than it changes the cutting, and the brake has a hard limit at full bed length.

Air-bend force per metre follows 1.42 × σb × t² / (1000 × V), with V, the die opening, usually set at 8× the thickness. Because the die opening grows with the gauge, the squared term is partly cancelled and the force ends up close to linear in thickness.

Work it for CRCA D at 350–400 MPa; the table uses 400 MPa, the conservative case, on the 200 T, 4,450 mm brake:

• 3 mm, V = 24 mm: 213 kN per metre, which is 948 kN or 96.6 tonne-force across the full bed.
• 6 mm, V = 48 mm: 426 kN per metre, which is 1,896 kN or 193 tonne-force across the full bed, or 97% of the machine rating.
• 10 mm, V = 80 mm: 710 kN per metre, which is 3,160 kN or 322 tonne-force across the full bed.

The first two fit and the third does not. A 10 mm bend is a real capability on this brake, but over a shorter length: at 710 kN per metre, the 200 T rating is exhausted at about 2.8 m. A full-length 4,450 mm bend in 10 mm needs a bigger machine or a segmented sequence, and the drawing should not assume otherwise. Working to 75–80% of rating, the full bed is comfortable at 3 mm and outside that band at 6 mm, where a shorter bend or a larger V die is the safer plan.

Welding moves the same way. A 3 mm fillet on 3 mm sheet is one pass. A 5 mm fillet on 6 mm sheet is two passes, which doubles the heat input into the part and roughly doubles the distortion. That is why a gauge increase often shows up as a straightening operation rather than a welding one.

What Ganesh cuts, and how thickness is quoted

Ganesh quotes laser cutting from the actual sheet specified, not the nominal gauge, and the mass consumed per part is part of the quotation working. The 12 kW fibre laser and its 40 ft × 16 ft bed set the cut time; the two 6 kW and two 3 kW machines take the thin work so it does not wait behind thick plate. Mild steel, CRCA, stainless, aluminium, brass and copper are cut in-house from 0.8 mm to 20 mm, with 30–40 mm plate work on the iron worker.

Thickness is quoted from the actual sheet specified, not from the nominal figure, and the mass consumed is part of the quotation working. Where the part is coated afterwards, the seven-tank pretreatment adds a fixed cost per part rather than a thickness-dependent one, so on thin parts coating can be a larger share than cutting. The plants hold ISO 9001:2015 and ISO 14001:2015, and customer programmes include Mahindra, Mahindra Powerol, Godrej & Boyce, TKE, Eros Elevators, Minda, Gunnebo and Indian Railways.

The laser cutting capability page lists the material and thickness range, and the laser cutting and fabrication hub carries the tolerance, nesting and edge guides that sit beside this one.

What to put in the RFQ

• Material grade, thickness and the standard the sheet is bought to.
• The mass per part, if the drawing or model carries it, so the material line can be checked.
• Total cut length and pierce count, if the CAD system reports them.
• Quantity and release pattern, because setup and programming amortise over the order.
• Any face that must be square or machine-flat after cutting.
• The gauge you would like to try, if a reduction is possible.
• Whether the part is formed, welded or coated afterwards, and where.

Send the DXF and the STEP through the quotation route. For an indicative machine cost before that, the laser cutting cost estimator takes the cut length, thickness, pierce count and quantity with your own rates. The weight calculator gives the mass per part, which is the number that usually explains the quote.

When thickness is not the cost driver

Four cases where a different process or a different question matters more than the gauge.

Stable, high-volume geometry. Once a part runs at volume, a press tool blanks it in under a second and the laser is the wrong route at any thickness. The stamping versus laser cutting by volume guide has the crossover.

Very thick section. Above 20 mm, the laser stops and the plate goes to the iron worker, a shear and a drill. Below 40 mm that is often cheaper than a thermal cut, because the edge needs no machining afterwards.

Coating-dominated parts. A small 1 mm bracket weighs 0.5 kg and costs little to cut, but it still goes through pretreatment, powder and curing at a per-part cost that does not scale with thickness. On those parts the coating quote, not the cutting quote, decides the supplier.

Tolerance-dominated parts. A part that needs ±0.1 mm on a formed face is a press or machining job, and thickness is irrelevant to the decision. The tolerance limits guide sets out what the cut can hold and where the next operation takes over.