Sheet metal bending prices: how is a quote calculated?

Bending means deforming a flat sheet, cut beforehand, along a straight line to give it an angle. It is most often done on a CNC press brake: a punch (the upper tool) pushes the sheet into the V-opening of a die (the lower tool). A bending quote is not a universal “price per bend”: it is the sum of several items, some depending on the part and others on the quantity.

The items in a quote for a bent part

• Material: the sheet is paid for by the size consumed, offcuts included.
• Prior cutting: laser cutting or punching of the flat pattern (the part laid flat), with its holes, notches and reliefs.
• Press setup: choosing and fitting the tools, programming the bend sequence, approving the first part.
• The bending itself: handling and bending each part, a time proportional to the number of bends.
• Additional operations: deburring, inserting fasteners, tapping, welding, finishing.
• Inspection and delivery: checking angles and dimensions, protecting visible surfaces, packaging, transport.

Bending is almost always quoted together with cutting, because the two are prepared together: the workshop calculates the flat pattern, checks that the part can be bent with its tools, then programs the sequence. Covers, guards, enclosures, brackets and frames, very common in special-purpose machinery, follow this pattern; the workshops concerned are grouped on the sheet metal and cutting page.

Eight factors explain most of the gaps between two quotes. The table shows which way each one pulls; their real weight depends on your part.

These factors add up: a thick stainless steel part with eight bends and tight tolerances cannot be compared with a mild steel bracket with two bends, even at similar dimensions. The guide on the price of laser cutting and bending covers the cutting side in detail.

The number of bends and their sequence

Each bend is set against stops, bent, then the part is turned or repositioned. The order matters: an edge already raised can block access to the next bend, and a four-sided box often requires narrow or segmented tools. That is why, on complex parts, bending time increases faster than the number of bends alone.

Length and thickness

The force required grows with the bend length and the strength of the material. For a given V-opening, it varies roughly as the square of the thickness: the V is therefore widened for thick sheet, which enlarges the resulting radius and requires a longer bent flange. The usable length and the power of the press limit what is feasible: beyond a few metres of bend or for heavy thicknesses, few workshops are equipped.

The material

• Mild steel: the simplest and most economical case.
• Stainless steel: higher force than mild steel of the same thickness and more pronounced springback, which the workshop compensates for by adjusting the angle. Visible surfaces require tool protection or films.
• Aluminium: lower force, but behaviour depends on the alloy and its temper: some hard alloys crack if the radius is too tight. State the grade (see the guide on materials).

The press is fitted with standard tools (straight or gooseneck punches, multi-V dies) that cover most parts. A specified inside radius that matches no tool, a hemmed bend (an edge folded flat), a Z-offset or a particular profile call for special tooling. On a run it is amortised; on a few parts, it weighs heavily.

Setup covers tool changes, positioning the stops and approving the first part. It is charged once per batch. Bending time per part therefore comes down to: setup time ÷ quantity + unit bending time.

The example below is fictitious: it illustrates the mechanism, not a price. Assumptions: 30 minutes of setup and first part, and a 4-bend part that needs 1.5 minutes of bending and handling.

Multiplied by the press hourly rate, these times give the share of bending in the price. That rate varies with the workshop, the machine and the workload: we do not put a figure on it, because no general figure would be honest. Keep the scale in mind: at the same pace, the single part here takes about seventeen times as long as a part from a run of one hundred.

Bending is a less accurate process than laser cutting. In standard production, you can expect an angle of around ±1°, to be confirmed with the workshop. Tighter values are possible with angle measurement during bending, but they add setup, inspection and scrap: reserve them for functional bends.

Dimensions accumulate uncertainties. The real thickness of the sheet varies within its own tolerance, springback is never identical from one part to the next, and each bend adds a position. A dimension between two holes on either side of a bend therefore carries a wider tolerance than between two holes in the same plane, in the order of a few tenths of a millimetre depending on the part. If your drawing specifies nothing, state general tolerances: the ISO 2768 tool lets you read the deviations for each class.

The cutting that comes first sets the quality of the flat pattern. The workshop calculates it from the thickness, radius, angle and its tooling, taking into account the neutral axis (the zone that neither lengthens nor shortens during bending), whose position is expressed by the K-factor, generally between 0.3 and 0.5. Preferably send the bent part in 3D (STEP): the workshop unfolds it itself, with its own parameters. Avoid holes too close to a bend (they become oval) and provide a relief cut where two bends meet.

1. Standardise radii. A single inside radius, around the thickness for mild steel, avoids tool changes and special tools.
2. Limit the number of bends and orient them in the same direction, to reduce turning.
3. Keep bends accessible: avoid very short flanges, closed boxes and hemmed edges when a simple return flange will do.
4. Harmonise material and thickness across the references of one assembly, so they can be cut from the same sheets and bent with the same tools.
5. Tighten only the functional tolerances on angles and dimensions.
6. Group quantities or place a framework order with staggered deliveries, rather than several small batches.
7. Accept an alternative proposed by the workshop (equivalent grade, neighbouring thickness, modified bend) when it does not change the function.

Finally, think about the treatment after bending: paint, galvanising or anodising add thickness and lead time. The guide anodising, powder coating or galvanising helps you choose before freezing the design.

The more complete the request, the faster and more comparable the quotes. For a bent part, state:

• the dimensioned drawing (PDF), the 3D model (STEP) of the bent part and, if you have it, the DXF of the flat pattern;
• the material, grade and thickness, or “equivalent accepted”;
• the quantities, in several steps (for example 1, 10 and 100) to see the effect of setup;
• the required angles and radii, or “free radius” when the function allows it;
• the visible face and the protection expected (film, tool protection) for cosmetic surfaces;
• the critical dimensions and angles, with their tolerances, and the general tolerances of the drawing;
• the additional operations: deburring, inserts, tapping, welding, surface treatment;
• the inspection and documents expected (report, material certificate), the lead time and the delivery location.

On Meaflow, posting a request is free and commission-free: you receive quotes from several workshops, compare them, ask your questions by messaging and choose.