Cost

What Drives Cost Per Unit in Fab Equipment Manufacturing

A bottoms up cost model for fab equipment modules, where machine hours and cleanroom labor dominate and where quotes quietly go underwater.

Costing a fab equipment module means resolving five buckets: material, machine time, cleanroom labor, scrap and rework, and burdened overhead. For a vacuum chamber assembly, machine time and cleanroom labor usually dominate, not raw metal. A defensible quote builds each line bottoms up from the traveler, then adds contingency for the leak check loop that estimators routinely forget. This guide breaks down where the dollars sit and where quotes drift, and points to the Clean Assembly Labor, Module Rework Cost, and Bakeout Energy Cost calculators for the line items that hide the most money.

Start with material. A 316L or 316LN stainless chamber body of 150 kg at 8 to 15 dollars per kg of certified plate is only 1,200 to 2,250 dollars raw. Electropolishing, material certs, and UHV grade stock can add 30 to 60% to that. Aluminum 6061 tools run cheaper per kg but demand more careful sealing. Ceramics like alumina or aluminum nitride jump to hundreds of dollars per kg and drive isolator and heater costs. Material rarely exceeds 15 to 25% of a finished chamber price, which is why chasing metal discounts returns so little.

Machine time is the big lever. A five axis CNC loaded at 120 to 250 dollars per hour, times 40 to 120 hours for a chamber with many sealing faces and blind bores, lands at 4,800 to 30,000 dollars. Estimate hours from cycle time per feature, not gut feel: 60 features at an average 1.2 hours each is 72 hours. Setup and fixturing add 8 to 20% on low volume runs. Because hours swing so widely, a 10% error here dwarfs any material misjudgment, so tie the estimate to the Chamber Machining Yield expected scrap rate.

Cleanroom assembly labor carries a premium. Fully burdened ISO 5 technician time runs 75 to 140 dollars per hour, and gowning plus airlock cycles add 10 to 20% of nonproductive time that must be costed, not absorbed. A chamber taking 24 assembly hours at 100 dollars loaded is 2,400 dollars, but at a 15% gowning overhead the real figure is closer to 2,760. The Clean Assembly Labor calculator converts headcount, gown time, and cleanliness class into a burdened hourly figure so you stop quoting bench rates for cleanroom work.

Scrap and rework is where margins vanish. If chamber machining yield is 90%, one in ten bodies is reworked or scrapped, and a scrapped body forfeits both material and every machine hour already spent, easily 5,000 to 15,000 dollars. The leak check loop is worse: a failed helium test can mean disassembly, reclean, and rebake, adding 8 to 40 hours. Price this with the Module Rework Cost calculator using a realistic 5 to 10% rework rate, not the optimistic 1% that sales wants. One reweld on a sealing face can erase the whole job's profit.

Overhead is the quiet multiplier. Cleanroom operating cost runs 50 to 200 dollars per square foot per year for ISO 5, covering HEPA, makeup air, and monitoring, and that floor cost must be allocated per tool by dwell days. Bakeout energy, by contrast, is minor, often under 10 dollars per run, so do not over model it, but do capture the 24 to 72 hours a bay is occupied during bake, because occupancy, not kilowatt hours, is the real cost. A tool sitting 3 days in a bakeout bay may carry more allocated overhead than its entire energy bill.

Build the quote as a stack: material, machine hours times loaded rate, cleanroom labor times burdened rate, expected scrap from yield, allocated overhead by dwell days, then a contingency of 8 to 15% for the rework loop. A 150 kg chamber might total 2,000 material, 12,000 machine, 3,000 labor, 2,500 scrap, and 4,000 overhead, so about 23,500 before margin. Add 12% contingency and a 30% margin and you quote near 34,000. Skipping contingency is the single most common way these bids go underwater on the first leak failure.

The recurring miss is queue time. Metrology and calibration wait days between operations, and that idle inventory carries overhead even though no labor posts against it. Estimators also forget helium cost on leak testing, which is no longer trivial, and they quote cleanroom hours at machine shop rates. Sanity check any quote against dollars per kilogram of finished tool: a UHV chamber typically lands at 150 to 400 dollars per kg all in, so a 150 kg body priced under 22,500 or over 60,000 deserves a second look before it goes out the door.

Published 2026-07-02.