CNC Machining, Defense and Aerospace Industry Term Glossary
Sometimes it helps to understand a bit more behind the terminology. This glossary can help define some of the common (and not so common) terms heard and seen in CNC machining for industrial, defense, and aerospace markets.
What is ITAR?
International Traffic in Arms Regulations (ITAR) is a strict U.S. regulatory framework that controls the manufacture, sale, and export of defense-related articles, services, and technical data. Governed by the Department of State, ITAR protects national security by ensuring military and aerospace technologies—including custom CNC-machined components—stay out of foreign hands. For aerospace and defense buyers, partnering with an ITAR-registered machine shop is essential to legally share blueprints, manufacture parts, and secure sensitive government supply chains.
Resources:
- Learn more about regulations and controls on the State Department Directorate of Defense Trade Controls (DDTC) landing page.
- Review guidelines and penalty information via the DDTC Public Portal Compliance Page.
- Browse the live, updated regulatory text at the Electronic Code of Federal Regulations (e-CFR) for ITAR.
Check out our article: Precision CNC Machining and ITAR: What Defense Buyers Need to Know
What is ISO9001?
ISO 9001 is the global benchmark standard for Quality Management Systems (QMS), applicable to any organization regardless of industry size or sector. It focuses on core business processes, continuous improvement, risk-based thinking, and strong customer satisfaction.
ISO 9001 vs. AS9100
While ISO 9001 provides the baseline framework for general quality management, AS9100 takes that exact framework and adds roughly 100 intense, aerospace-specific requirements. AS9100 introduces strict regulations for risk management, configuration control, product safety, and supply chain traceability that general manufacturing under ISO 9001 does not require.
Resources:
- ISO Official 9001 Page: The International Organization for Standardization’s home for the standard, detailing its core principles and benefits.
- ASQ (American Society for Quality): A comprehensive repository of articles, training tools, and implementation guides for ISO 9001.
- ANSI National Accreditation Board (ANAB): The premier accreditation body providing insight into the certification process and auditing requirements for ISO QMS standards.
Check out our article: AS9100D and ISO 9001:2015 Certified Manufacturer: What It Means for Buyers
What is GD&T (Geometric Dimensioning and Tolerancing), and why is it important in engineering, CNC machining, and inspection?
GD&T (Geometric Dimensioning and Tolerancing) is a standardized symbolic language used on engineering blueprints to precisely define the allowable variation of a part’s shape, form, orientation, and location.
In engineering, traditional plus-minus tolerancing often creates ambiguous square tolerance zones that can cause parts to fail during assembly even if individual measurements look correct. GD&T focuses directly on the functional relationships of a design, utilizing controls like flatness, cylindricity, and true position to ensure mating components always fit and operate properly in the real world.
In CNC machining, GD&T provides machinists with vital context about design intent. Rather than treating every surface with the same rigid accuracy, machinists can easily identify which features are critical for assembly and which are less vital. This clarity optimizes fixture design, toolpath programming, and machining strategies, saving time and reducing production costs.
During inspection, GD&T establishes a repeatable framework for quality control. Inspectors use specified datums—ideal reference points or planes—to mirror how the part functions in an assembly. Using advanced tools like Coordinate Measuring Machines (CMMs), they accurately verify whether physical parts meet the geometric limits set by the engineer.
Ultimately, GD&T acts as a universal communication bridge. It eliminates guesswork, ensures consistency across global supply chains, and guarantees that manufactured components fit and function exactly as intended.
What Is Design for Manufacturability (DFM)?
Design for Manufacturability (DFM) is an engineering methodology focused on intentionally designing parts, assemblies, and products to be manufactured as easily, efficiently, and cost-effectively as possible.
Rather than designing a component in isolation and figuring out how to build it later, DFM integrates production realities directly into the initial design phase. Engineers collaborate closely with manufacturing teams to analyze how material selection, geometry, tolerances, and finishing processes impact production. For CNC machining, this means avoiding unnecessary tight tolerances, eliminating hard-to-reach internal pockets, standardizing hole sizes, and ensuring proper workholding access so parts can be machined quickly and without specialized tooling.
The primary benefit of DFM is the elimination of downstream waste. By addressing potential manufacturing bottlenecks early, companies drastically reduce scrap rates, shorten machining cycle times, minimize tool wear, and lower overall production costs.
In demanding sectors like aerospace, medical device manufacturing, and defense, DFM ensures that complex components meet stringent quality frameworks without sacrificing manufacturability. Ultimately, DFM bridges the gap between creative design and shop-floor reality, ensuring that components can be produced reliably, repeatably, and profitably at scale.
Learn more about DFM and how it can reduce cost, risk, and production delays.
What is Controlled Unclassified Information (CUI), and how does it impact precision CNC machining and parts creation?
Controlled Unclassified Information, or CUI, is unclassified information that the federal government requires to be safeguarded or subject to controlled dissemination under applicable laws, regulations, or policies.
In precision manufacturing, aerospace, and defense contracting, CUI may appear in the technical and production information used to manufacture a component. Not every defense-related document is automatically CUI. Its status depends on the information’s content, contract requirements, customer flow-downs, and authorized markings or handling instructions.
Examples may include:
- Engineering Data: CAD models, drawings, specifications, GD&T requirements, and technical data packages.
- Derived Manufacturing Data: CAM files, setup sheets, tooling models, and G-code when they contain or reveal controlled technical information.
- Quality and Production Records: Bills of materials, First Article Inspection Reports, CMM results, nonconformance records, and manufacturing plans when they disclose protected technical or program information.
CUI can exist electronically or in printed form. Machine shops must control how applicable files, drawings, travelers, inspection records, emails, removable media, and cloud systems are accessed, stored, transmitted, displayed, and destroyed.
For Department of Defense work, contractors that process, store, or transmit CUI are generally required by contract to implement applicable NIST SP 800-171 security requirements. CMMC provides a method for assessing and verifying that implementation.
The specific CMMC requirement depends on the solicitation, contract, subcontract, information involved, and current implementation rules. The practical objective is not to treat every document as CUI, but to correctly identify protected information, restrict access to authorized personnel, and safeguard it throughout the manufacturing and quality process.
What is CNC machining?
CNC (Computer Numerical Control) Machining is a high-precision, subtractive (meaning we remove material, not add it, like in 3d printing – or additive) manufacturing process where pre-programmed computer software spins milling tools (metal, carbide, diamond tipped, etc.) at high spin rates to remove material in very precise cuts. Modern CNC manufacturing utilizes advanced CAD models translated into G-code (geometric toolpaths) and M-code (miscellaneous machine functions) to automatically carve parts from solid blocks of raw material. Most of the encoding can be done with advanced software, but human machinists play a critical role in understanding what is technical feasible, and what isn’t.
This process is critical for producing flight-grade, high-reliability components across the aerospace, defense, and industrial sectors. Multi-axis CNC machining centers—ranging from standard 3-axis mills and lathes to highly complex 5-axis systems—hold strict tolerances down to ±0.0001 inches, retaining 100% of a material’s native structural integrity. It is widely utilized to shape demanding metals like titanium, aluminum, steel, and high-temperature Inconel for turbine blades or landing gear, as well as rugged engineering plastics like Delrin, ABS, and PEEK for industrial bearings, seals, and electronics housings.
What is CMMC Level 2?
CMMC Level 2 is a mandatory Department of Defense cybersecurity certification proving a machine shop has passed a strict, independent audit to securely handle sensitive military blueprints and defense data. Achieving this certification proves a machine shop securely handles sensitive military data and digital blueprints. This status, validated by an independent third-party audit (C3PAO), confirms compliance with 110 strict cybersecurity practices from NIST SP 800-171. It protects national security and is mandatory for manufacturing parts and bidding on Department of Defense contracts. See Borg Design certifications including CMMC Level 2 (C3PAO) >>
Resources:
- Review the full technical framework on the DoD CIO CMMC Site
- Review the NIST SP 800-171 guidelines
- Download the exact 110-control standard from the DoD CMMC Level 2 Assessment Guide
- Learn about the third-party ecosystem at The Cyber AB C3PAO Directory
Check out our article: What is a CMMC Level 2 Certified Machine Shop and What Does it Mean?
See our latest blog on the subject here: CMMC Phase 2 Is Paused: What Defense Buyers Should Do Next
What is CMM inspection?
CMM Inspection (Coordinate Measuring Machine)
CMM inspection is a high-precision quality control process used in manufacturing to verify that a physical part perfectly matches its original 3D blueprint or CAD (Computer-Aided Design) model.
Instead of using manual tools like hand calipers, a Coordinate Measuring Machine (CMM) uses an automated robotic arm to map a part's exact shape in 3D space:
- Precision Probing: The machine guides a highly sensitive probe (often tipped with a microscopic ruby ball) to tap or scan different points on the part's surface.
- 3D Coordination: Every single touch records a precise coordinate along three axes ($X$, $Y$, and $Z$).
- Digital Comparison: Advanced software aggregates these points and digital overlays them onto the CAD model, instantly highlighting any microscopic variations between the physical part and the design intent.
Why does a shop having CMM matter? it's all in the accuracy of inspection.
- CMM measures features like roundness, flatness, and hole alignment down to a single micrometer ($\mu\text$)—which is roughly 1/100th the thickness of a human hair.
- It (almost) guarantees compliance: It ensures parts adhere strictly to complex GD&T (Geometric Dimensioning and Tolerancing) requirements.
- It offers near zero-fail performance: It provides repeatable, automated data that eliminates human error, making it crucial for zero-defect industries like aerospace, defense, and medical manufacturing.
What is AS9100?
AS9100 is the international quality management system (QMS) standard specifically written for the aerospace, aviation, and defense industries. Managed by the International Aerospace Quality Group (IAQG), it builds upon the standard requirements of ISO 9001 by adding stringent, industry-specific criteria.
The standard focuses on ensuring product safety, reliability, and regulatory compliance. It enforces rigorous controls over risk management, product configuration, critical items, special processes, and supply chain traceability. Achieving AS9100 certification is a critical prerequisite for manufacturers and suppliers aiming to work with major aerospace primes and defense contractors.
Resources:
- IAQG Official Website: The governing body that develops and maintains the AS9100 series standards.
- SAE International – AS9100 Standard: The official platform to purchase, preview, and review the technical specifications of the current AS9100 (Revision D) standard.
- NIST MEP Aerospace Quality Management Guide: The National Institute of Standards and Technology provides manufacturing extension partnership resources and guidance for small-to-mid-sized manufacturers looking to implement AS9100.
Check out our article: AS9100D and ISO 9001:2015 Certified Manufacturer: What It Means for Buyers
What is an AS9102 First Article Inspection? (aka FAI)
First Article Inspection (FAI) is a critical quality verification process where a defense or aerospace buyer requires a CNC machine shop to thoroughly evaluate a part from the initial production lot. Governed by SAE AS9102, it provides objective evidence that the shop’s processes, tooling, and programming can repeatedly manufacture components meeting strict military and aviation specifications.
The FAI process consists of three major phases:
- Planning & Ballooning: Identifying and numbering every engineering requirement on the technical drawing.
- Manufacturing & Evaluation: Machining the part and measuring every ballooned characteristic using calibrated tools.
- Documentation & Review: Compiling findings to verify compliance.
The mandatory deliverables are wrapped into a final First Article Inspection Report (FAIR), which includes:
- Form 1: Part Number Accountability
- Form 2: Product Accountability (materials and special processes)
- Form 3: Characteristic Accountability (actual dimensional results)
Resources:
- Review the primary aerospace publishing framework on the SAE AS9102 Standard Page.
- Review the global international governance on the IAQG 9102 Standard Overview.
- Download an executive implementation example from the Lockheed Martin MFC Supplier FAI Guidebook.
- Learn about major aerospace buyer deployment workflows via the Boeing Supplier Portal FAI Planning Page
What is 3D printing?
Think of 3D printing as an advanced manufacturing process that builds objects from the ground up, adding plastics or resins in ultra-thin layers based on a digital design, rather than cutting material away from a solid block.
While some industrial processes use metals, operations primarily focus on resin technology. This method uses specialized light to harden liquid resins layer by layer. It is the go-to solution for businesses because it delivers exceptional accuracy, smooth surface finishes, and fine details. It is widely used for creating rapid prototypes, custom manufacturing tools, and high-precision finished products quickly and efficiently.