CNC Machining

Overview

CNC machining removes material from a solid stock block or bar to create precise metal or plastic parts. It is strong for functional prototypes, low-volume production, fixtures, mechanical components, and parts that need real material properties and controlled dimensions.

When to choose

• Choose CNC when the part needs metal strength, engineering plastic properties, threaded features, flatness, accurate holes, bearing seats, sealing surfaces, or repeatable mechanical fit.
• It is often a good choice for 1 to several hundred parts when tooling would be too expensive or too slow.
• Use CNC when surface finish and dimensional control matter more than the free-form geometry advantages of 3D printing.

When not to choose

• Avoid CNC for very organic internal channels, extremely thin walls, or shapes that cannot be reached by cutting tools.
• For simple flat metal parts, laser cutting or sheet metal may be cheaper.
• For high-volume plastic production, injection molding may become more economical after tooling cost is justified.

Required files

Design rules

• Use internal corner radii where possible because round cutting tools cannot create sharp internal corners.
• Avoid unnecessarily deep pockets, long thin walls, and small deep holes because they increase machining time and tool risk.
• Define threads clearly with size, pitch, depth, class, and whether they are tapped or threaded inserts.
• Apply tight tolerances only to functional interfaces; leave non-critical features at typical process tolerance.
• Consider tool access from realistic machining directions, especially for undercuts and side features.

Typical materials

Tolerance expectations

CNC can achieve strong dimensional control, but tolerance depends on geometry, material movement, setup, tool access, surface finish, and inspection method.

Cost drivers

• Machine time from material removal, deep pockets, small tools, tight toolpaths, and multiple setups.
• Material price and stock availability.
• Tight tolerances, special inspection, surface roughness, and post-processing.
• Small features, threads, inserts, deburring, and manual finishing.

Lead-time factors

• Standard materials and relaxed tolerances usually quote and produce faster.
• Hard materials, large parts, special plastics, heat treatment, plating, or CMM reports add time.
• Supplier location and current machine capacity affect delivery speed.

Uretyco AI workflow

1. 1
   Geometry analysis

   Uretyco checks tool access, pockets, holes, wall thickness, size, and likely setup complexity.

2. 2
   Material and tolerance questions

   The assistant asks whether strength, corrosion, heat, precision, or appearance matters most.

3. 3
   Quote and options

   The engine compares machine time, material, finish, quantity, inspection, and supplier capacity.

4. 4
   Production review

   Critical drawings or ambiguous features can be reviewed before supplier assignment.

Quality notes

• Provide a drawing for every critical dimension that must be inspected.
• Mark visible surfaces if cosmetic tool marks or handling marks are important.
• Confirm burr removal, sharp-edge breaks, thread depth, and any required certificates before ordering.

FAQ

• Can I order CNC without a drawing? Yes for simple parts, but drawings are needed for critical tolerances, threads, fits, or inspection.
• Can CNC make sharp internal corners? Not usually. Add internal radii or reliefs where mating parts require a corner.
• Can Uretyco suggest cheaper CNC changes? Yes. The assistant can flag deep pockets, tight tolerances, and material substitutions.