Manufacturing Glossary — 45+ Terms Defined

CNC Machining 3D Printing (Additive Manufacturing)Sheet Metal Fabrication Materials & Properties Surface Finishing Quality & Inspection General Manufacturing

CNC Machining

CNC Machining: Computer Numerical Control machining — a subtractive manufacturing process where computer-controlled cutting tools remove material from a solid block (billet) to produce precision parts with tight tolerances and excellent surface finishes. Learn more
3-Axis Machining: CNC machining where the cutting tool moves along three linear axes (X, Y, Z). Suitable for most prismatic geometries. Parts may require multiple setups to access all features.
5-Axis Machining: CNC machining with three linear axes plus two rotational axes (typically A and B). Allows complex geometries, undercuts, and angled features to be machined in a single setup with better surface finish and tighter tolerances.
Tolerance: The permissible variation in a dimension. For example, ±0.005″ means the actual dimension can be 0.005 inches above or below the nominal value. Tighter tolerances increase cost due to slower feeds, finer tools, and additional inspection. Learn more
GD&T (Geometric Dimensioning & Tolerancing): A symbolic language defined by ASME Y14.5 that controls the form, orientation, location, and runout of features — not just their size. GD&T uses feature control frames with symbols like flatness (⏥), perpendicularity (⊥), and true position (⊕). Learn more
Ra (Roughness Average): The arithmetic average of surface profile deviations from the mean line, measured in microinches (µin) or micrometers (µm). Lower Ra = smoother surface. As-machined CNC typically achieves 63–125 Ra µin; grinding can reach 8–16 Ra µin. Learn more
Billet: A solid block of raw material (metal or plastic) from which a CNC part is machined. Common billet forms include bar stock, plate, and round stock.
Feeds and Speeds: The feed rate (how fast the tool moves through material) and spindle speed (RPM). Optimizing feeds and speeds for the specific material and tool reduces cycle time, improves surface finish, and extends tool life.
Fixturing: The method of holding a workpiece in place during machining. Fixtures include vises, clamps, vacuum tables, and custom jigs. Poor fixturing leads to vibration (chatter), dimensional errors, and scrapped parts.

3D Printing (Additive Manufacturing)

Additive Manufacturing: 3D printing — building parts layer by layer from digital CAD files. Unlike subtractive machining (which removes material), additive processes deposit or fuse material only where needed, enabling complex internal geometries and lattice structures. Learn more
SLS (Selective Laser Sintering): A powder-bed 3D printing process that uses a CO₂ laser to sinter (partially melt) nylon powder layer by layer. Produces strong, functional parts without support structures. Standard layer height: 100–120 µm. Typical tolerance: ±0.3 mm. Learn more
SLA (Stereolithography): A resin-based 3D printing process that uses a UV laser to cure liquid photopolymer layer by layer. Produces the finest detail and smoothest surfaces among common 3D printing technologies. Layer height: 25–100 µm. Learn more
FDM (Fused Deposition Modeling): A 3D printing process that extrudes thermoplastic filament (ABS, PLA, PETG, Nylon, TPU) through a heated nozzle, depositing material layer by layer. The most cost-effective additive process for large parts and functional prototypes. Learn more
MJF (Multi Jet Fusion): HP's powder-bed 3D printing technology that uses an inkjet array to deposit fusing and detailing agents onto nylon powder, then fuses with infrared energy. Produces production-quality PA12 parts with isotropic mechanical properties. Learn more
DMLS (Direct Metal Laser Sintering): A metal 3D printing process that uses a high-power laser to fully melt and fuse metal powder layer by layer. Produces fully dense metal parts in stainless steel, titanium, aluminum, Inconel, and cobalt chrome. Learn more
Metal FFF (Fused Filament Fabrication): A metal 3D printing process that extrudes a metal-polymer composite filament to form a "green part," which is then debound and sintered in a furnace to produce a fully metal part. Lower cost than DMLS for simple geometries. Learn more
Layer Height: The thickness of each deposited layer in a 3D print. Thinner layers produce smoother surfaces and finer detail but increase build time. Typical values: 25 µm (SLA) to 200 µm (FDM).
Support Structures: Temporary structures printed alongside the part to support overhanging features during the build. Required for SLA and FDM; not needed for SLS and MJF (the unsintered powder acts as support).
Build Orientation: The direction in which a 3D printed part is oriented on the build platform. Affects surface finish, mechanical properties (due to layer bonding anisotropy), support requirements, and build time.

Sheet Metal Fabrication

Sheet Metal Fabrication: A manufacturing process that transforms flat metal sheets into functional parts through cutting (laser, waterjet, punch), bending (press brake), welding, and finishing. Ideal for enclosures, brackets, panels, and structural components. Learn more
Laser Cutting: Using a focused laser beam (CO₂ or fiber) to cut sheet metal with high precision. Fiber lasers are faster on thin metals; CO₂ lasers handle thicker sections and non-metals. Typical kerf width: 0.1–0.3 mm.
Press Brake Forming: Bending sheet metal using a CNC press brake — a machine that presses a punch into a die to form precise bends. Inside bend radius is typically ≥1× material thickness. Tighter radii risk cracking.
Bend Radius: The inside radius of a sheet metal bend. Minimum bend radius depends on material, temper, and thickness. A common rule: minimum inside radius = 1× material thickness for aluminum, 1.5× for stainless steel.
K-Factor: The ratio of the neutral axis position to material thickness in a sheet metal bend. Used to calculate flat pattern (blank) dimensions. Typical values: 0.33–0.50 depending on material and bend angle.
Hem: A sheet metal edge that is folded back onto itself (180° bend) to eliminate sharp edges, add stiffness, or create a finished appearance. Open hems leave a small gap; closed hems are fully flattened.

Materials & Properties

Yield Strength: The stress at which a material begins to deform permanently (plastically). Below yield strength, deformation is elastic (reversible). Measured in MPa or ksi. For Al 6061-T6: 276 MPa (40 ksi). Learn more
Tensile Strength: The maximum stress a material can withstand before fracture under tension. Also called Ultimate Tensile Strength (UTS). For Al 6061-T6: 310 MPa (45 ksi).
Elongation at Break: The percentage a material stretches before fracturing under tension. Higher elongation = more ductile. Al 6061-T6: 12–17%. PEEK: 30–50%. Ti-6Al-4V: 10–14%.
Hardness (Rockwell): A measure of a material's resistance to indentation. Rockwell scales include HRB (softer metals like aluminum) and HRC (harder metals like tool steels and titanium). Al 6061-T6: ~60 HRB. Tool steel A2: ~60 HRC.
Machinability: How easily a material can be cut with standard tooling. Free-machining steels (12L14) and aluminum (6061) have excellent machinability. Titanium and Inconel are difficult to machine — requiring slower speeds, rigid setups, and specialized coatings.

Surface Finishing

Anodizing: An electrochemical process that grows a hard, corrosion-resistant aluminum oxide layer on the part surface. Type II (decorative) is 5–25 µm thick and can be dyed. Type III (hardcoat) is 25–75 µm thick with >65 HRC hardness.
Passivation: A chemical treatment (nitric or citric acid) that removes free iron from the surface of stainless steel, enhancing its natural corrosion resistance. Required for medical and food-contact stainless steel parts.
Powder Coating: An electrostatic dry finishing process where charged powder particles are sprayed onto a part and cured in an oven at 350–400°F. Produces a durable, uniform coating in any RAL color. Typical thickness: 50–80 µm.
Bead Blasting: Propelling glass or ceramic beads at the part surface under air pressure to produce a uniform matte finish. Removes tool marks and machining lines. Typical finish: 100–250 Ra µin.
Electropolishing: The reverse of plating — material is dissolved from the part surface in an electrolytic bath, smoothing peaks and removing micro-burrs. Commonly used on stainless steel medical devices to achieve Ra < 10 µin.

Quality & Inspection

CMM (Coordinate Measuring Machine): A precision instrument that measures the geometry of physical objects by sensing discrete points on the surface with a probe. CMMs achieve measurement uncertainty of ±0.001 mm (±0.00004″) and produce dimensional inspection reports.
FAI (First Article Inspection): A complete inspection of the first production part against all drawing dimensions, typically per AS9102. Documents that the manufacturing process can consistently produce parts within specification.
PPAP (Production Part Approval Process): An automotive-industry quality framework (AIAG) that verifies a supplier can consistently reproduce parts to specification. Includes dimensional results, material certs, process flow diagrams, control plans, and capability studies.
MTR (Mill Test Report): A document from the material supplier certifying the chemical composition and mechanical properties of a specific heat/lot of metal. Required for traceability in aerospace, medical, and defense applications.
CoC (Certificate of Conformance): A document signed by the manufacturer certifying that the parts meet all specified requirements — dimensions, material, finish, and any special processing. Included with every MakerStage order upon request.
DFM (Design for Manufacturing): The practice of designing parts so they can be manufactured efficiently, reliably, and cost-effectively. DFM review catches issues like insufficient draft angles, overly tight tolerances, or features that require expensive secondary operations. Learn more

General Manufacturing

RFQ (Request for Quote): A formal request sent to a manufacturer with CAD files, drawings, material specs, quantity, and delivery requirements. The manufacturer reviews the package and returns a price quote and lead time. Learn more
Lead Time: The total time from order confirmation to parts shipping. Includes manufacturing, finishing, inspection, and packaging. Typical lead times: 1–3 days (3D printing), 10–15 days (CNC/sheet metal).
Prototype: A preliminary version of a part built to validate design, fit, and function before committing to production tooling or processes. Prototypes are typically 1–10 units with faster turnaround and higher per-unit cost.
Bridge Tooling: Temporary, lower-cost tooling (typically aluminum molds) used to produce initial production quantities (500–5,000 units) while steel production tooling is being manufactured. Bridges the gap between prototyping and full production.
Injection Molding: A high-volume manufacturing process where molten plastic is injected under pressure into a steel or aluminum mold cavity. Economical at 1,000+ units. Tooling costs range from $2,000 (aluminum) to $200,000 (multi-cavity steel). Learn more

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