Sheet metal fabrication cost: every process measured in its own unit

Sheet metal costing goes wrong in a specific way: the shop settles on one unit — usually parts per hour — and applies it to every process. Then a part with a long, intricate cut profile and a part with a simple outline cost the same, and nobody can explain why one job made money and the other did not.

The fix is to measure each process in **the unit that actually drives its time**.

Each process has its own unit

The ten categories, in process order

1. Material — sheet consumed, not part area

Charge the part with the sheet area it actually consumes, which includes its share of the skeleton left behind. Costing the part outline alone leaves the offcut unpaid for, and in this trade the offcut is a large fraction of the sheet. The nesting guide covers how to apportion it.

2. Machine time

One rate per machine — a fiber laser, a turret punch and a press brake are three different rates. Convert to per part using the unit from the table above, not an average across the shop.

3. Labor

Separate the blocks that behave differently: loading and unloading sheets, breaking parts out of the skeleton, deburring, forming, and assembly or hardware insertion. Break-out and deburr are pure handling and they scale with part count, not with machine time.

4. Tooling and consumables

Nozzles, lenses, punch and die sets, press brake tooling, deburring media. Cost divided by parts produced between changes, exactly as in the machining guide.

Tooling made specially for one part — a dedicated punch, a custom form tool — is a **one-off cost**, not a consumable. Handle it the way the machinery guide handles non-recurring cost.

5. Scrap

Parts cut wrong, formed to the wrong angle, or damaged in handling. Record where the loss happened: a part scrapped after forming has consumed cutting, handling and forming, not just material.

6. Rework

Re-bending, straightening, weld repair, refinishing. If your shop scraps rather than reworks, enter zero — not blank.

7. Outside processing

Powder coating, plating, galvanizing, anodizing, silk screening. Vendor price for the lot divided by pieces, plus freight both ways. Coating is usually priced by area or by rack space, so a flat part and a formed part of the same weight can cost very differently.

8. Packaging

Formed parts nest badly and scratch easily, so packaging is heavier here than in machining. Interleaving, edge protection and returnable containers all belong on the sheet.

9. Freight

Fabricated assemblies are bulky before they are heavy, so a truck usually **runs out of space before it runs out of weight**. Cost a shipment and divide by the parts it held, and note the assumption.

10. Shop overhead

Space, power, compressed air, extraction, supervision. Allocate on a consistent basis. If assist gas or power is already inside the machine rate, do not charge it again here — that double count is the most common one in this trade.

Three things to check

1. Material is sheet consumed including skeleton share, not part outline area.
2. Bending is costed with handling time, not machine time alone.
3. Assist gas and power appear exactly once, either in the machine rate or in overhead.