IQC — incoming
Review specified material certificates and, where required, alloy chemistry before stock is released to machining.
CNC Machining Quality Control & Inspection
CNC machining quality control built around your critical requirements. We align drawing features, inspection coverage, and required records, then combine CMM and in-process metrology at the authorized manufacturing facility to support the agreed inspection plan.
Inspection flow
IPQC — in process
First-article checks after setup or relevant tool changes, operator self-checks, and roaming inspection keep agreed critical dimensions under review during machining.
FQC — before ship
Verify agreed dimensional and GD&T characteristics before shipment, with the inspection records specified for the order.
What “100% inspection” means here
Quality control starts with the features your part relies on. During DFM, we align the drawing revision, critical characteristics, inspection methods, coverage, and required records. That gives machining and inspection a shared set of requirements before production begins.
Whether you are sourcing industrial automation parts or developing an automotive component, the aim is the same: define the important checks early and make the agreed results straightforward to verify.
Turn functional requirements into an inspection plan
Start with fit, location, motion, sealing, and load transfer. Connect each functional requirement to the drawing and a suitable way to evaluate it:
- Fits and mating interfaces: identify the shaft, bore, or locating feature and its mating condition. Evaluate required form and alignment alongside size.
- Location and orientation: use the drawing datums to define relationships such as a hole pattern to a mounting face. Agree an inspection setup that represents those requirements.
- Surface and edge condition: identify sealing/contact faces, burr-sensitive edges, and specified surface texture, with a suitable check for each.
- Acceptance state: identify whether limits apply before or after coating, heat treatment, or another operation, including masking and protected interfaces. See surface finishes and fit allowances.
For each selected characteristic, agree its drawing reference or balloon ID, nominal and limits or GD&T callout, datums, inspection stage, method, coverage, and record. This inspection focus sits alongside all other drawing requirements. See CNC drawing and design guidelines for preparing the inputs.
Match inspection coverage to the agreed requirements
Named critical characteristics receive 100% checking when agreed in the order / DFM plan: each part is checked for those features. Other characteristics may use sampling with a defined lot, sample size, selection method, frequency, and acceptance rule. This makes the extent of inspection clear; it does not imply CMM measurement of every dimension on every part.
A first-article check covers the inspected article and selected features at that stage. Ongoing production and shipment checks follow the agreed plan; sampling supports a lot decision without establishing the conformity of every unmeasured part.
Resolve nonconformances before release
When a check identifies a nonconformance, we hold the affected parts from release and arrange rework, additional inspection, or an agreed disposition. Any release that departs from the original requirements needs customer approval. The agreed records link drawing requirements to results and the inspected sample or lot, so engineering and purchasing can check what was covered.
How we measure
| Instrument | Suitable task | Planning considerations |
|---|---|---|
| ZEISS SPECTRUM CMM | Datum-related locations, 3D geometry, and drawing-specified GD&T for agreed features | Plan datum alignment, fixturing, probe access, and point strategy. Surfaces or form not captured by the program need an appropriate additional evaluation. |
| Optical comparators | Accessible 2D profiles, silhouettes, and drawing overlays | Set orientation and edge visibility for the projected contour. Internal or 3D requirements outside that view need another suitable method. |
| Spectrometers | Specified incoming alloy/chemistry checks alongside material-certificate review | Match the method to the alloy and required elements. Mechanical-condition evidence and heat/lot identity also need confirmation. |
| Calipers | Accessible external/internal dimensions and depths for general production checks | Consider jaw contact, alignment, measuring force, temperature, and the required limit. Display resolution alone does not establish suitability. |
| Micrometers | Selected diameters or thicknesses with suitable anvils, range, and access | Control contact force and part restraint. A two-point diameter reading needs separate evaluation of any roundness, cylindricity, or datum-related runout requirements. |
| Thread gauges | GO / NO-GO checks using plug or ring gauges matched to the specified thread | Confirm thread form, size, pitch, class, gauge condition, and procedure. Thread depth, position, and other drawing requirements need suitable checks of their own. |
Note
CMM, optical comparison, and production-floor gauges provide complementary ways to check the agreed features. We select the method around the characteristic, tolerance, material, access, and acceptance state. Surface texture, hardness, and other special requirements need a separately confirmed method and scope.
Choose a method that supports the required limit. Instrument identification, calibration status, fixturing, temperature, and measurement uncertainty all matter. Agree an acceptance decision rule where uncertainty affects a result near a limit; display increments and traceability alone do not establish fitness for that task.
Technical references: Mitutoyo measuring-instrument guide, ZEISS guidance on CMM inspection errors, and NIST guidance on traceability and fitness for purpose. These provide general metrology guidance; project capability is confirmed through DFM.
Programmed CMM checks cover complex 3D geometry and GD&T when the drawing and inspection plan call for it. Scope is always per drawing and agreed at order / DFM — not an unconditional CMM pass on every feature of every part.
Operators and roaming inspectors use micrometers, calipers, and gauges for setup checks and critical diameters during machining. Production-floor measurements complement programmed CMM work so IPQC catches drift early — before FQC release.
Case study: in-process diameter inspection of 1045 steel
During machining, an operator uses an outside micrometer to check a cylindrical outside diameter on a 1045 steel turned part. The photograph shows the measurement being taken while the part remains held in the lathe chuck.
The inspected feature has a specified tolerance of ±0.05 mm. This is the requirement for this feature, not a measured result or a general machining capability. The nominal dimension is withheld for confidentiality.
What this example shows
This is an in-process inspection (IPQC) example. No inspection report or measured reading is available for this case, so no dimensional conformity or pass/fail result is claimed. The photograph documents the inspection activity; it does not establish final inspection, batch acceptance, or inspection frequency.
For a similar turned part, share your drawing and critical dimensions through Request a Quote. See CNC Turning Service for the machining process.
Tolerance posture
| Level | Typical statement | Condition |
|---|---|---|
| Standard delivery | ±0.10 mm | Only where no individual or general drawing tolerance applies; confirm the quotation basis |
| Milling / turning selected features | Selected features may be reviewed to ±0.01 mm | Material and geometry allow — confirmed via DFM |
| Critical 5-axis features | Designated critical features may be reviewed to ±0.005 mm | Designated features only — confirmed via DFM / per drawing |
| Project reality | Drawing + DFM win | Industry tables are reference, not a contract for every PO |
Note
For general-tolerance selection and conditional feature capability, see functional tolerances and GD&T. Apply any specified general tolerance to its stated scope and edition. Where no individual or general drawing tolerance applies, ±0.10 mm is a common delivery basis, to be confirmed in the quotation. Delivery limits follow the controlled drawing and confirmed DFM / order requirements.
Documentation available on request
| Document | What it covers | What to verify |
|---|---|---|
| Standard dimensional report | Agreed dimensions, nominal / tolerance, measured results, and pass-fail status, linked to the drawing revision and inspected sample or lot | Use characteristic IDs and units to match requirements to results. Distinguish measured values from attribute checks and confirm sample or lot identification. |
| FAI / fuller layouts | Customer-specified FAI forms and drawing-characteristic coverage are available when specified and quoted. | Agree drawing-note and feature coverage, article identity, and any exclusions. Confirm shipment-lot inspection separately from the first-article package. |
| MTR / material certs | Heat/lot-linked chemistry and mechanical data where applicable | Match grade/specification and heat/lot references from the certificate to the supplied material and delivered lot. |
| Certificate of Conformance (CoC) | Shipment-level statement against the PO / drawing when requested | Match the PO, part/revision, quantity, and referenced requirements. Review requested dimensional results and material evidence alongside this declaration. |
| CMM report | Programmed CMM results for features in the inspection plan | Match feature IDs, datums/alignment, limits, results, and sample identities to the agreed CMM coverage. |
Note
Customer-specified FAI forms and drawing-characteristic coverage are available when specified and quoted. For aerospace first-article inspection requirements, see SAE AS9102C. Required forms, coverage, and compliance scope must be stated on the RFQ/PO; this does not claim blanket AS9102 compliance or replace drawing, statutory, or regulatory requirements.
NDA and design data
We can sign an NDA before you send CAD. Files are limited to engineers assigned to the job and to permitted manufacturing and finishing recipients. Download our standard NDA (PDF), email yours to [email protected], or attach it with your RFQ upload. We may use desensitized machining-process or in-process photos that do not identify you or your part; email to opt out. Privacy practices: Privacy Policy.
What to include in your inspection RFQ
Share your drawing and inspection priorities so we can align the quotation, machining plan, and acceptance records:
- Current drawing revision and CAD, with units, applicable standards, critical dimensions, datums, and GD&T identified
- Material grade/condition, finishing requirements, and whether acceptance applies before or after those operations
- Named features for 100% checking, plus the sampling coverage and any separate FAI requirement to agree
- Required dimensional, FAI, MTR, CoC, or CMM records, including customer forms and sample/lot identification
- Order quantity, any special acceptance or deviation requirements, and an NDA where needed
A clear path from quotation to receiving inspection
- Before the PO: agree the drawing revision, critical features, inspection stages, methods, coverage, and records. Confirm the production location and inspection responsibility through Jaquent's manufacturing and trading authorization.
- In the quotation: specify the document package and confirm any requested calibration or traceability evidence is available and included.
- At receipt: match the PO, part/revision, delivered quantity, sample or lot identity, and agreed characteristic coverage. Reconcile missing records or revision differences with the supplier, and check any customer-approved deviation against the affected features and quantity.
Illustrative inspection-plan entry: OD-01 | drawing reference and nominal/limits | acceptance after the specified final operation | suitable micrometer, subject to method review | agreed coverage | record linked to the delivery lot. This is a planning example, not a customer result; form and datum-related requirements need their own evaluation.
When requesting sampling: Name the characteristic and lot, the sampling standard and edition if used, inspection level where applicable, AQL or other agreed risk basis, selection method, sample size, acceptance/rejection rule and action after a failed lot decision. "AQL 1.0" alone neither selects a complete plan nor authorizes shipping 1% nonconforming parts. Define every-part checking separately. NIST's sampling-plan overview explains how a plan supports a lot decision.
Request a Quote with your drawing, quantity, and inspection priorities. We can then review machining and verification together.
Quality FAQ
Do you always CMM every part?
No. We combine CMM with production-floor micrometers and gauges according to the drawing and agreed inspection plan. Named features receive every-part checks when specified; CMM coverage may include first-article, critical GD&T, or sampled checks.
Can I get reports with the shipment?
Yes, when requested and included at quote / order. Agreed dimensional records can link the drawing revision and inspected features to measured results and the corresponding sample or lot. Specify any FAI, MTR, CoC, or CMM output so its scope and format are included.
How do tolerances get confirmed?
Tight limits are always evaluated against material and geometry during DFM and locked per drawing. See also Precision & Tolerance Standards.
How do you choose a suitable inspection method?
We consider the feature, required limit, material, access, acceptance state, fixture, and measurement environment. Calibration status and uncertainty support that choice; display resolution or traceability alone is not enough. The agreed method and acceptance rule define how the characteristic is evaluated.
What should purchasing verify in the inspection package?
Match the PO, part number, drawing revision, sample or lot identity, and agreed feature coverage to the supplied records. Check the requested results, material references, and approved deviations. Review CoC and CMM documentation against their stated scope.
Ready to start your CNC project?
Share the available drawing and inspection priorities. Agree feature coverage, methods and required records together with machining scope before ordering.