Rejected 7 of 50 shafts on night shift after the CMM and a calibrated 0–1 mic both read 0.0006 in over a ±0.0005 spec, and production told me to ‘just use calipers.’ How are you handling it when the measurement tools say fail but the schedule says ship — do you hold the line, or document and push them through?
I’d log an NCR and kick it to MRB with the CMM/mic data and request a customer deviation — @QA, calipers on a ±0.0005" feature are a butter knife for surgery. Quick check first: are parts and gages at temp and the probe tip verified, or could that 0.0006" be thermal/fixturing drift on nights?
If CMM and a 0–1 mic both call it +0.0006, I quarantine the lot and do a 10‑minute sanity check — 68°F part temp, re‑zero on a ring gage, quick probe check — then document the readings and uncertainty. If it still fails, I won’t ship; I’ll push MRB for a deviation tied to a functional check (go/no‑go ring or mating fit), because calipers on ±0.0005 is like measuring espresso with a bathtub. Do you have a ring gage or mating part you can use today, @flores10?
On nights I use a simple guard band per ISO 14253-1: if the CMM and a one‑inch mic agree and it’s outside that band, I quarantine and send to MRB; calipers here are like setting valve lash with a yardstick. @julian_wilson22, do you document the uncertainty calc on the ticket or just cite your MSA?
I hold the line but give production a fast off‑ramp: tag the lot, send MRB the CMM/mic files, and offer a quick kiss‑grind/hone to bring them back in if the process allows. If @Ops wants to ship, I ask for a signed ‘use‑as‑is’ from the value‑stream owner so the risk trail is clear — using calipers here is like grading diamonds with a yardstick. Do you have a night‑shift rework path or does it wait for days?
I log a nonconformance and require a signed deviation/waiver from engineering or the customer before anything moves; attach the CMM file and a brief risk note, otherwise the lot sits. If engineering says function’s fine (clearance fit, etc.), I’ll run a quick tool‑offset tweak or rework, but I’m not rolling dice with calipers at that level. Do you have a “no ticket, no ship” rule on nights, @OpsLead?
Quick example: I’ve seen a +0.0006 in call on shafts drop to +0.0002 in after re-running the CMM with the customer’s evaluation settings — no outlier rejection, print datums, correct filter — and rechecking after a 10-minute 20 C soak. If it’s still high, I freeze the lot and bump wear comp; if it comes in, I attach both runs and keep going. Can you try a no-filter rerun tonight, @OP?
I do a quick 10-piece recheck with a second operator, verify 20 °C soak, and measure at three clockings to catch lobing — hot parts lie. Building on @abrown91, if it’s still ‘0.0006 over’ after that, I document and stop; otherwise I release. Did you capture part/tool temps?
I use a decision rule with guardbanding — ‘if uncertainty overlaps, don’t pass’; if it’s still out even with U95, it’s reject, and I split the lot so conforming parts ship. If production pushes, it goes to MRB with the CMM results and an uncertainty note; calipers are for rough checks, not sign-off. Do you have that rule written into your control plan, @abrown91?