CNC Machining
A subtractive manufacturing process where computer-controlled cutting tools remove material from a solid block (billet) to create a finished part. CNC offers exceptional precision and works with metals, plastics, and wood.
CNC (Computer Numerical Control) machining uses computer-programmed machine tools -- mills, lathes, routers, and grinders -- to precisely cut material from a solid block into a finished part. Unlike injection molding or die casting which shape material, CNC is subtractive: you start with more material than you need and cut away the excess. This makes CNC ideal for prototypes, low-volume production, and parts requiring very tight tolerances.
CNC machining is the go-to process for metal prototypes, precision components, and products where surface finish and tolerances are critical. It works with virtually any machinable material: aluminum, steel, titanium, brass, copper, Delrin, nylon, PEEK, and more. Apple uses CNC machining to produce MacBook unibody enclosures from solid blocks of aluminum -- one of the most famous examples of CNC at consumer product scale.
The economics of CNC favor low to medium volumes. There is no tooling cost (the cutting tools are standard), so setup costs are minimal. However, per-unit costs are higher than injection molding or die casting at volume because each part requires significant machine time. CNC machining costs are driven by: material type and cost, part complexity (number of setups and operations), tolerances required, surface finish requirements, and quantity. It is common to prototype with CNC and then transition to casting or molding for production.
Why it matters
Use CNC machining for your first 50-200 units to validate your design before investing in injection mold or die casting tooling. This lets you iterate on the design without expensive mold modifications.
Practical Tip
Use CNC machining for your first 50-200 units to validate your design before investing in injection mold or die casting tooling. This lets you iterate on the design without expensive mold modifications.
You'll hear this when…
When briefing a factory
“"We need the CNC Machining process clearly documented in your quality control plan."”
When reviewing samples
“"Can you confirm which CNC Machining standard was applied during production of these samples?"”
When placing an order
“"The purchase order includes a clause requiring CNC Machining compliance for all production runs."”
Related Terms
Die Casting
A manufacturing process where molten metal is forced under high pressure into a reusable steel mold (die) to produce complex-shaped metal parts with high dimensional accuracy and smooth surface finish.
Tooling
The molds, dies, jigs, and fixtures required to manufacture a specific product. Tooling is typically a one-time upfront cost that enables mass production of your custom design.
3D Printing / Additive Manufacturing
A manufacturing process that builds parts layer by layer from digital files, using materials like plastic, resin, metal, or nylon. Ideal for prototyping and very low-volume production with no tooling required.
Bill of Materials
BOMA comprehensive list of all raw materials, components, sub-assemblies, and quantities needed to manufacture a finished product. The BOM is the foundation of cost estimation and production planning.
This term appears in every Bottlecap report.
See it in action — explore a full sample analysis.
Ready to put this knowledge to work?
Get a complete manufacturing feasibility report for your product idea — with cost breakdowns, supplier recommendations, and optimization tips.
Analyze my idea →