Quality Measures for CNC Machining
How we use digital manufacturing and quality control processes to manufacture quality parts consistently
Certifications ISO 9001:2015 | AS9100D | ITAR
Additional Certifications available via Protolabs Network of trusted manufacturing partners: ISO 13485, IATF 16949
Build Quality into Every Part from the Start
Quality starts long before production begins. Automated manufacturability analysis helps identify potential design challenges early, reducing the risk of delays, redesigns, and unexpected production issues.
Our digital analysis reviews designs for common manufacturing considerations, including:
- Walls that are too thin
- Parts that exceed manufacturing size limits
- Holes that are eligible for threading
When a potential issue is identified, you'll receive guidance to help evaluate your options. You can proceed with the design as-is or update and resubmit the model for review. Addressing these considerations early helps improve manufacturability and creates a smoother path to quality parts.
Verify Quality Throughout Production
After design review is complete, quality verification continues throughout manufacturing. In-process inspections help monitor critical features during production, while completed parts undergo visual and dimensional inspection before shipment.
Combined with standardized manufacturing processes and digital quality controls, these inspections help reduce variability, support consistent results, and provide greater confidence in the finished part.
Inspections for CNC Machined Parts
We offer several quality inspection reports and certifications for CNC machining orders. Depending on your project requirements, you can select from a range of inspection and documentation options to support production verification, dimensional validation, traceability, and compliance needs.
- First Article Inspection (FAI)
- Dimensional Inspection Report (DIR)
- Basic Production Inspection
- Material Certificate of Analysis (COA)
- Certificate of Conformance (CoC)
- Custom Inspection Services: if your project requires PPAP, or other needs, contact your account manager and we will review
Available Inspections
| First Article Inspection | |
|---|---|
| Benefits | Verifies the sample part conforms to all dimensions provided on a 2D drawing. |
| Measurements | Protolabs quality control will inspect 100% of dimensions provided on a 2D drawing, including GD&T. Quoted tolerances apply. |
| Services Provided By | Protolabs |
| Additional Features | FAI produced on a template conforming to AS9102C standard. |
| Eligibility | All |
| Additional Lead Time | 1 day |
| Price | Starting at $750 |
| Sample Plan | Revision CNC Machining Factory: After the parts have completed manufacturing, one piece from the lot is inspected to quoted dimensional tolerances and your visual standards. We perform AQL sample places for quantities over 50. Quick-Turn CNC Machining Factory: 100% of parts are inspected. |
| Additional Information | 2D drawing required |
| Dimensional Inspection Report | |
|---|---|
| Benefits | Verifies numerous dimensional specifications without requiring a 2D drawing. |
| Measurements | Protolabs quality control will inspect approximately 10 dimensions to quoted tolerances. GD&T will not be inspected. |
| Services Provided By | Protolabs |
| Additional Features | Protolabs formatted report with bubbled part image and results summary chart. |
| Eligibility | All |
| Additional Lead Time | N/A |
| Price | Starting at $500 |
| Sample Plan | Precision CNC Machining Factory: After the parts have completed manufacturing, one piece from the lot is inspected to quoted dimensional tolerances and your visual standards. We perform AQL sample places for quantities over 50. Quick-Turn CNC Machining Factory: 100% of parts are inspected. |
| Basic Inspection | |
|---|---|
| Benefits | Additional QC checks available |
| Measurements | X, Y, and Z dimensions, thread functionality, visual, and up to 4 place to plane measurements as specified by customer. |
| Services Provided By | Protolabs |
| Additional Features | Calipers and thread guages |
| Eligibility | All |
| Additional Lead Time | None |
| Price | $0 |
| Sample Plan | 100% |
| Additional Information | Additional customer specified measures, up to 4 plane to plane or hole features. CoC and CoA available upon request. |
| Material Certificate of Analysis | |
|---|---|
| Benefits | Protolabs standard Material Certification. A written confirmation providing traceability to the raw material used in your part(s), including material composition. |
| Measurements | N/A |
| Services Provided By | Protolabs |
| Additional Features | N/A |
| Eligibility | All |
| Additional Lead Time | None |
| Price | Starting at $60 |
| Sample Plan | N/A |
| Certificate of Conformance | |
|---|---|
| Benefits | Protolabs quality control will inspect parts to conform to quoted standards. No inspection documentation will be provided. |
| Measurements | N/A |
| Services Provided By | Protolabs |
| Additional Features | N/A |
| Eligibility | All |
| Additional Lead Time | None |
| Price | $0 |
| Sample Plan | N/A |
| Inspections without Report | |
|---|---|
| Benefits | Our basic QC process |
| Measurements | X, Y, and Z dimensions, thread functionality, and visual |
| Services Provided By | Protolabs |
| Additional Features | Calipers and thread gauges |
| Eligibility | All |
| Additional Lead Time | None |
| Price | $0 |
| Sample Plan | 100% inspection |
| Additional Information | CoC and CoA available upon request. |
Additional inspections are available and tailored to your requirements, allowing verification of numerous critical dimensions. Custom inspection services may also support specialized requirements, such as PPAP documentation.
Available to select in "inspections" during checkout. Contact your account representative with questions.
Protolabs' Sampling-Based
Inspection Process
To ensure consistent quality while maintaining fast turnaround times, Protolabs uses a sampling-based inspection process for BIR/DIR inspection reports rather than inspecting every part in a lot. Sample sizes are selected based on total lot quantity, as outlined in the table to the right, and are designed to provide reliable verification of dimensional accuracy and workmanship.
| Lot Size | 1 to 50 | 51 to 90 | 91 to 150 | 151 to 280 | 281 to 500 | 501 to 1,200 | 1,201 to 3,200 | 3,201 to 10,000 |
|---|---|---|---|---|---|---|---|---|
| Sample Size | 1 | 2 | 3 | 5 | 8 | 13 | 20 | 32 |
Support from CNC Machining Experts
Discuss your design with a CNC machining applications engineer who can answer any manufacturability questions you might have. Common design review topics include optimizing cost, tolerances, threading, and finishing options.
Schedule a free virtual meeting today
Machined Parts for Aerospace Applications
With capabilities such as AS9100, FAI, material traceability, NADCAP-certified coatings, and full technical drawing and quality requirement reviews, we can get your parts to you, as designed, in as little as 1 business day. This reduces time for iteration and speeds your transition to final part designs, both critical needs for the aerospace industry.
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