The short answer
For CNC lots, **CMM sampling** and **100% inspect** are different quote packages. Sampling (with a clear plan) usually keeps [quote-new.php](https://3dwk.com/quote-new.php) **rates.v1.1** QA estimate bands narrower. Blanket 100% CMM on every dimension widens bands fast—especially on multi-setup stainless and hot-alloy lots.
This guide is for buyers packaging inspection notes. Illustrations use an **Example part** only—not a customer FAIR package. Related: [CMM vs optical measurement](https://3dwk.com/resources/cmm-vs-optical-measurement-machined-parts), [first article inspection reports](https://3dwk.com/resources/first-article-inspection-reports), [GD&T callouts that raise CNC quote bands](https://3dwk.com/resources/gdandt-callouts-that-raise-cnc-quote-bands).
What to put on the RFQ
Name the plan: first-article full layout, then lot sampling (e.g. criticals every N pcs, minors per AQL-style note you actually use), or true 100% on a short critical list. Medical and aerospace stainless combos ([CNC 3-axis SS 316 medical](https://3dwk.com/en/cnc-3axis/ss-316/medical.html), [CNC 5-axis SS 316 medical](https://3dwk.com/en/cnc-5axis/ss-316/medical.html), [CNC turning SS 316 medical](https://3dwk.com/en/cnc-turning/ss-316/medical.html)) still need explicit sampling language—industry stickers alone do not define CMM minutes.
Put **FAI**, **SAMPLE PLAN**, and **100% CRITICALS** blocks on the PDF. Do not write only “inspect carefully.” Background: [DFM checklist before an online CNC quote](https://3dwk.com/resources/dfm-checklist-before-online-cnc-quote), [what files to send for a CNC quote](https://3dwk.com/resources/what-files-to-send-for-cnc-quote).
Criticals vs minors
Route true position, sealing diameters, and safety fits to CMM or equivalent. Leave ISO 2768-m stock sizes on shop checks unless you truly need layout data. Balloon only what you will pay to measure. Related datum help: [datum schemes for multi-setup CNC parts](https://3dwk.com/resources/datum-schemes-for-multi-setup-cnc-parts).
Soft plastics (PA66 time coeff ×0.8 under **rates.v1.1** estimates) still take CMM time if you demand full layouts. Harder alloys (17-4PH ×1.4, IN718/IN625 ×2.5, CoCr ×2.2) raise both machine and probe minutes; 100% layouts on hot alloys with line mids above ~$2000 planning bands often tip into **needs_manual**.
FAI, SPC and lot breaks
First-article full layout plus reduced lot sampling is a common buyer-useful pattern. If you need capability evidence, say which dimensions and how many pieces—do not paste a generic “SPC all” sticker. Quantity breaks change unit CNC cost but can increase total inspection minutes if every piece is still 100% laid out—see [how quantity breaks change CNC unit cost](https://3dwk.com/resources/how-quantity-breaks-change-cnc-unit-cost), [prototype vs production CNC quotes](https://3dwk.com/resources/prototype-vs-production-cnc-quotes).
Bar $/kg planning bands (estimates only): PA66 ~5, 17-4PH ~9, IN718 ~55, IN625 ~60. Material $/kg rarely dominates the inspection story—balloon count does. 17-4PH H900/H1025 +$60/lot estimate language is separate from CMM; still call heat treat if required before final inspect.
Illustration 1 shows an **Example part** balloon set: five criticals for sampling vs a full 40-dimension 100% fantasy.
Gauging vs layout CMM
Not every critical needs a full CMM layout. Go/no-go threads, pin gages, and functional checks can cover repeats after FAI proves the process. Say which criticals stay on CMM each lot and which move to shop gages. Mixing “CMM everything” with “ship tomorrow” is what triggers **needs_manual**. Keep report format notes short (PDF balloons + actuals) unless your quality clause demands a named template—and if it does, attach or link that template rather than renaming it in one vague sentence.
For turned + milled manifolds, split rotational diameters from prismatic true positions so estimators do not assume one marathon CMM program for every feature.
When 100% CMM is justified
Very small lots, safety-critical fits, or unstable processes may justify 100% on a **short** critical list. 100% on every drafted dimension is rarely the economical packaging. Optical methods may replace CMM on 2D profiles—see [CMM vs optical measurement](https://3dwk.com/resources/cmm-vs-optical-measurement-machined-parts)—but say which method per feature family.
Aerospace stainless siblings: [CNC 3-axis SS 316 aerospace](https://3dwk.com/en/cnc-3axis/ss-316/aerospace.html), [CNC 3-axis SS 304 aerospace](https://3dwk.com/en/cnc-3axis/ss-304/aerospace.html).
Example part walkthrough
**Example part:** 316 stainless manifold block ~90×60×30 mm, qty 50. FAI: full layout on 1 pc. Lot plan: five critical true positions + two seal bores CMM on 5 pcs/lot; other ISO 2768-m features shop-check. With STEP + balloon list + SAMPLE PLAN text, expect a clearer QA-inclusive planning band on [quote-new.php](https://3dwk.com/quote-new.php) than “CMM everything.” Same CAD with 100% of 35 balloons often widens the band or lands **needs_manual**—without inventing any customer AS9102 package.
Illustration 2 contrasts a vague “100% inspect” note versus a criticals sampling RFQ block and the clearer estimate path.
What widens bands fastest
Unbounded balloon counts, 100% CMM with no criticals list, conflicting FAI templates, and hot-alloy lots with full layouts plus tight cosmetics. See [what needs_manual means](https://3dwk.com/resources/what-needs-manual-means-preliminary-quote), [reading preliminary online quote min/mid/max](https://3dwk.com/resources/reading-preliminary-online-quote-min-mid-max).
What to do next
Balloon criticals, pick FAI + sampling or short 100% list, then upload on [quote-new.php](https://3dwk.com/quote-new.php). Service pages: [CNC machining](https://3dwk.com/cnc-machining-service.php), [materials](https://3dwk.com/materials.php). Treat **rates.v1.1** min/mid/max as estimates, not invoices.
Common questions
Is AQL mandatory language on every RFQ?
Use whatever sampling language your quality system recognizes—but be specific. Vague “AQL” without levels/criticals still creates clarification.
Does FAI replace lot sampling?
No. FAI proves the first article; lot sampling watches the run. State both when qty > 1.
How do hot alloys change CMM packaging?
Longer probe + machine cycles under **rates.v1.1** coeffs make unbounded 100% layouts expensive; expect wider bands or manual review.
Can optical inspection replace CMM entirely?
Sometimes for 2D edges and profiles. 3D true positions and deep bores often still need CMM or equivalent—assign method per feature.