How to quote a sheet metal part
The print shows a sheet metal part, a mounting bracket in 0.120 inch cold rolled steel with 4 bends, 6 holes, 2 pressed nuts and a zinc finish. Annual volume 4,000, released in lots of 500. It looks like a 10 minute quote and it is the kind of part that quietly loses money for 3 years.
Every figure below is illustrative, built to show where the lines come from rather than to be copied. The bracket carries through the whole post so the arithmetic stays connected. It follows the same method as the machined part build-up on a different process.
Where the money sits in a sheet metal part
The instinct is that cutting is the cost, and on most formed parts it is third at best. Material is usually first, forming is second once setup is spread across a lot of 500, and the laser time everybody focuses on is a smaller line than the plating that happens down the road.
The order matters because it tells you where to spend estimating attention. A 5 percent error on material moves the price more than a 20 percent error on cut time, and the material line is the one most often taken from a catalog price rather than from what you will actually buy.
The other reason to lead with material is that it is the line the customer will challenge first, because it is the only one they can look up. Being able to show the yield behind it turns that conversation into arithmetic.
The package matters as much as the print here. A sheet metal request that arrives as a flat DXF is a different job from one that arrives as a formed 3D model with no flat pattern, because in the second case somebody has to develop the blank before anything can be nested or priced. Reading the package first decides how much of the next hour is estimating and how much is drafting.
Material and the nesting yield you actually get
Quote the sheet you buy, not the area of the part. How the blanks are laid out on it, which is nesting, decides the difference. The bracket’s flat blank is 8.25 by 5.50 inches, which is 45.4 square inches. Nested on a 48 by 96 sheet with a 0.25 inch web and normal edge clearance, an illustrative layout yields 84 blanks from a sheet.
That sheet is 4,608 square inches. Eighty four blanks consume 3,814 of it, which is a yield of 83 percent. The remaining 17 percent is drop, and you paid full price for every square inch of it.
At an illustrative $1.05 a pound for 0.120 CRS, that sheet weighs about 188 pounds and costs $197. Divided by 84 good blanks the material line is $2.35 a piece, against $1.95 if you had costed the part area alone. That 40 cent gap is 20 percent of the material line and it is pure yield.
You buy sheets, not parts.
Two things move this number more than anything else. Grain direction, covered below, can force a nesting orientation that drops yield by 10 points. And lot size decides whether you nest this part alone or combine it with others, which is why a quote for 500 and a quote for 50 are different parts commercially.
Cutting cost, and why per inch beats per part
Cutting is a length problem, so price it by the inch and let the geometry decide. The bracket has a 27.5 inch perimeter and 6 holes contributing another 9.4 inches of internal cut, giving 36.9 inches total.
At an illustrative machine rate that works out to a cut time under a minute, which is why the cut line lands near $0.85 a piece. The important part is what sits around it. Every pierce has a pierce time, so 6 holes cost more than their cut length suggests, and the kerf the process removes has to sit between every pair of nested parts.
Load and unload matter more than most estimators carry. A sheet that takes 40 seconds to load and 90 seconds to sort and stack is adding real minutes per sheet, and at 84 parts a sheet those minutes divide down to a line that is small but never zero.
Cut length, not part count.
Cutting method changes the shape of this line rather than just its size. Laser is fast on thin material and slows sharply as thickness climbs. Punching is quick per hit and needs tooling for anything other than round holes. Waterjet does not care about hardness and is slow.
The estimating consequence is that the method has to be chosen before the line is priced, and on a package that arrives with no routing that choice is an assumption the estimator is making silently. Write it on the quote. When the customer comes back at a higher volume, the assumption is the first thing worth revisiting.
The burdened rate on the cutting cell is doing the work here, and it needs to include the assist gas, the consumables and the utilisation you actually run rather than the hours the machine is switched on.
Bend count, setup and the deduction that changes the blank
Forming is a setup problem with a small cycle attached, which is the opposite of how it usually gets quoted. Four bends on this bracket means 4 hits, and if 2 of them need a different tool it also means a tool change in the middle of the run.
At an illustrative 25 minutes of setup and 22 seconds a part of handling and forming, a lot of 500 carries the setup across 500 pieces and the forming line is around $0.42. The same part in a lot of 50 carries the same setup across 50, and forming becomes $0.95. The part did not change.
Here is the first of the 2 things most often missed. The flat blank is not the sum of the legs. Material stretches through a bend, so the developed length is shorter than the outside dimensions added together, and the difference is the bend deduction.
Get it wrong and the blank is wrong. On this bracket, at 0.120 material with a 0.125 inside radius, an illustrative deduction of 0.21 inches per bend across 4 bends means the blank runs 0.84 inches shorter than a naive addition would suggest. Quote the naive blank and you have bought 10 percent more steel than the part needs, on every piece, for the life of the program.
Grain direction, and what it does to both lines
The second commonly missed item is grain, and it touches material and scrap at the same time. Rolled sheet has a grain running along the direction it was rolled, and bending across the grain behaves differently from bending along it.
A tight bend running parallel to the grain will crack on some materials and finishes, particularly on harder tempers and heavier gauges. If the print calls out grain direction, or the finish makes it a functional requirement, the blank orientation on the sheet is fixed before nesting starts.
That constraint costs yield. A part that nests at 83 percent when it can be rotated freely might nest at 72 percent when every blank must run the same way, and 11 points of yield on the largest line of the quote is not a detail.
Grain fixes the nest before you nest it.
The failure mode is worse than a pricing error. A quote built on free nesting that then has to run grain constrained loses the difference on every lot for 6 years, and nobody revisits the estimate once the part is running.
Hardware, finishing and the operations nobody lists
The bracket has 2 pressed nuts, a deburr and a zinc finish, and none of those are on the print as operations. Hardware insertion is a press cycle plus the hardware cost plus the handling, and on a 2 nut part it is an illustrative $0.34 all in.
Deburr is labour and it scales with edge length and hole count, not with part size. On a laser cut part with 6 holes it is a real line, and it is the one most often absorbed into an overhead percentage where nobody can see it.
Zinc plating is outside processing, so it carries a supplier price, a minimum lot charge, freight both ways and a lead time that sits on your schedule. Quote it as a line with a named supplier, because a plating minimum on a lot of 50 can exceed the machining.
Stacking it up for the bracket at 500 pieces gives an illustrative $2.35 material, $0.85 cutting, $0.42 forming, $0.34 hardware, $0.28 deburr and $0.46 plating, which is $4.70 before margin. Material is exactly half.
That distribution is why a weldment and a bracket should never be quoted with the same mental model, and why the machined part build-up lands somewhere different again. The operations decide the shape of the number before any of the rates do.