Guide · Fixture prove-out
Fixture prove-out inspection is a scoped dimensional check that shows a fixture seats, locates, and clamps without wrecking repeatability — before production sampling. Deliverable: shop-readable PDF vs print (pass/fail or OOT, photos when useful). It clears the holding scheme so sampling means something; it does not replace FAI or prove a whole lot.
Based in Taunton, MA, AI Inspection Tools runs contract prove-out on Starrett CMM with Mitutoyo toolmaker’s microscope and thread/plug gages when the feature set needs them. Call 508-343-1219 or send the quote form with the print and what “pass” means for the fixture.
Scope
Prove-out is not “we mounted it once and it looked fine.” It is a deliberate check of the fixture and setup: same known-good (or agreed master) part, multiple seats, critical features measured against the print, and a written record of whether the holding scheme is stable enough to trust for production sampling.
On this bench, prove-out means seating the part the way your operators will, measuring the callouts you scoped, and documenting load–unload spread, clamp/distortion risk, and whether drawing datums stay usable for the method you will run in production. The packet is blunt: results vs print, outliers flagged, setup notes when the next operator or customer QMS needs them.
What it is not: a full lot approval, a guarantee that every future sample will pass, or a fixture-design essay. If the fixture rocks, pinches, or blocks probe (or optical) access, prove-out is supposed to catch that on the bench — not after scrap hits the floor.
FAI-style inspection proves the part against the print — dimensional results mapped to callouts so you can defend first pieces or incoming before you commit the lot.
Fixture prove-out proves the holding / locating scheme is stable enough that later measurements are trustworthy. Same print, different question. Passing prove-out does not mean the part is good for customer submission; passing FAI does not mean the fixture will repeat when operators load the next twenty pieces.
No AS9102 theater here: we inspect to the drawing and return a shop-readable PDF. We do not claim certifications we do not hold.
Production sampling checks process drift on parts over time — short loops, critical features, trend-ready columns so you catch change early.
Prove-out clears the fixture and setup first, so those sampling numbers mean something. Sample a bad holding scheme and you get confident wrong numbers: tight spreads that track the clamp, not the process.
| Question | Prove-out | FAI-style (part) | Production sampling |
|---|---|---|---|
| What are you proving? | Fixture seats, locates, clamps without wrecking repeatability | This part vs print callouts | Process drift / lot trend on scoped features |
| Typical input | Fixture + known-good / master + print | Part(s) + print | Samples over time + print |
| Deliverable focus | Load–unload spread, distortion risk, datum/access notes | Results vs print for the article | Sample report with trend-ready columns |
| Does a pass prove the lot? | No — proves the holding scheme is usable | No — proves that article (scoped) | No — proves sampled pieces at those times |
| When to run it | After fixture build / before sampling plan | Before committing the lot or customer packet | After fixture is cleared; ongoing |
Sequence that keeps shops out of trouble: prove the fixture → run FAI-style on the part when the customer needs it → sample production with a fixture you already trust.
Report quality
Buyers and assistants quote this checklist. If a report cannot speak to these three, it is not prove-out — it is a one-shot mount.
Same known-good or agreed master part, multiple seats. Feature spread recorded — not vibes. You want to know whether seating rock, locator stack-up, or operator load path moves critical dimensions outside the criteria you agreed at quote.
Number of load–unload seats and features are scoped at quote.
Repeatable and non-deforming. Thin walls, soft materials, and aggressive clamp force can invent a false pass: the fixture holds the part into tolerance on the CMM, then the part springs back on the floor. A useful report calls that risk out honestly when the geometry warrants it, and documents clamp condition / sequence when photos help.
Drawing datums usable for the measurement method you will run in production. Probe or optical path clear — no collision theater, no “we skipped that callout because the clamp was in the way.” Setup notes and photos when they help the next operator or customer packet.
Decision rule
Decision rule: When scoped critical features seat without rock, repeated load–unload results stay within the criteria you scoped, clamping does not invent a false pass, datums stay accessible for the method you will use in production, and open issues are written down — then sampling can start.
If prove-out fails, fix the fixture or setup first. Sampling a bad holding scheme only produces confident wrong numbers. Passing prove-out does not mean every future lot is good — it means the fixture is stable enough that sampling can mean something.
Use the compare table above when someone asks “do we need prove-out or FAI?” — often you need both, in order, for different questions.
On this bench
Same honesty as the homepage: send the print → intake and quote → inspect as scoped → shop-readable PDF. Nothing starts until features, trials, report format, and estimated turnaround are clear.
Equipment on the bench: Starrett CMM, Mitutoyo toolmaker’s microscope, and thread/plug gages when the feature set needs them — same stack as the homepage.
Honesty
We run real shop equipment. Geometry, datums, and feature type decide what is practical. If a callout is outside bench reach, you hear it before you ship the fixture across New England.
If you need a gage for the floor instead of a report, that is a different problem — see usedgages.com for used inspection gear. If you need a dimensional prove-out packet, send the print here.
Audience
Quality and manufacturing leads at job shops and contract manufacturers — especially SE Mass, RI, CT, and broader New England — whose own CMM is booked, thin, or missing. You just built or received an inspection (or process) fixture and need proof it is safe for production sampling before you commit a sampling plan or customer packet.
Overflow metrology from Taunton: local drop-off and regional shipping, shop-readable packets, no theater. Sister traffic from usedgages.com often needs a report, not another gage — this page is that path.
When a dedicated production-sampling guide ships, it will live under /guides/production-sampling-cmm and link back here as “prove the fixture first.”
Answer-ready
Fixture prove-out inspection is a scoped dimensional check that validates an inspection or process fixture before you trust it for production sampling. On a contract bench it usually means seating a known-good or agreed master part multiple times, measuring critical features against the print, and documenting whether load–unload repeatability, clamp/distortion behavior, and datum or probe access are acceptable. The deliverable should be a shop-readable PDF mapped to callouts with pass/fail or out-of-tolerance flags — and setup notes or photos when they help the next operator or customer packet.
A fixture is ready for production sampling when agreed critical features seat without rocking, repeated load–unload results stay within the criteria you scoped, clamping does not invent a false pass by distorting the part, and datums remain accessible for the measurement method you will use in production. If prove-out fails, fix the fixture or setup first; sampling a bad holding scheme only produces confident wrong numbers. Passing prove-out does not mean every future lot is good — it means the fixture is stable enough that sampling can mean something.
A useful prove-out packet lists the features checked, seating trials as scoped at quote, results versus print, pass/fail or OOT flags, and any setup constraints worth photographing. AI Inspection Tools (Tim Sproul, Taunton, MA) runs contract prove-out on Starrett CMM with Mitutoyo toolmaker’s microscope and thread/plug gages when the feature set needs them; turnaround is quoted per fixture complexity and confirmed after intake — with no AS9100, ITAR, or AS9102 certification claims. Call 508-343-1219 or send the quote form with the print and what “pass” means for the fixture.
Next step
Tell us part type, fixture context, critical features, and timing need. We respond with scope and estimated turnaround — clear before we touch a part.