Automotive component costing: machine build economics, inverted by volume

The build-up matches **machinery manufacturing**: an assembly of made parts, bought parts and subcontracted parts. Read that guide first — the three-way split and the double-count trap when you supply material to a subcontractor both apply unchanged.

What differs is volume, and it reverses which categories matter.

One-time cost sinks, but does not disappear

Tooling, fixtures and design spread over program-lifetime volume, so the per-unit share becomes small. That tempts people to leave the field empty altogether, and that is the error.

Why it must be entered anyway: if the program ends earlier than planned, the unrecovered balance is a real loss. An entered figure can be recalculated; an empty field means nobody knows how much is still outstanding.

Cost of quality becomes a major category

At low volume, inspection is a few minutes of the operator's time. At high volume with very low defect targets, it becomes a block of its own:

• 100% or sampled inspection — labor, or gauge and machine time.
• Records and lot traceability — clerical time, plus retention cost.
• Retained samples and periodic destructive testing — product made that is never sold.

The third is the one most often missed, because it looks like ordinary production. It is **product with no revenue**, so it behaves like scrap — record it there, noting the cause is retained sampling rather than a defect.

Three changes from the machinery guide

The remaining seven follow the machinery guide.