Core line, represented 25+ years

Production machining, turning, and sawing

CNC machining is a subtractive process in which computer-controlled mills, lathes, and saws cut metal or plastic parts from bar, plate, tube, castings, or forgings. It needs no hard tooling, holds ±0.005 in (±0.13 mm) as standard and ±0.001 in (±0.025 mm) on critical features, and suits quantities from one prototype to thousands of production parts a year.

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Where it pays off

1101001k10k100k1M+

At a glance

No hard tooling, so a single part is possible. Above about 5,000–10,000 parts a year, a near-net process plus finish machining usually costs less.

Standard tolerance: ±0.005 in (±0.13 mm), or ISO 2768-m
Precision tolerance: ±0.0005–0.001 in (±0.013–0.025 mm) on critical features
Surface finish: Ra 63–125 µin (1.6–3.2 µm) as machined; 16–32 µin (0.4–0.8 µm) with finishing passes
Milling envelope: About 40 × 20 × 20 in (1,000 × 500 × 500 mm) on typical vertical mills; larger on horizontal and gantry machines
Turning capacity: Diameters to about 16 in (400 mm) on typical production lathes
Sawing tolerance: Bandsaw ±0.010–0.030 in (±0.25–0.8 mm); precision cold saw ±0.002–0.005 in (±0.05–0.13 mm)
Minimum wall: About 0.030 in (0.8 mm) in metal; 0.060 in (1.5 mm) in plastic
Typical volumes: 1 to about 10,000 parts a year

Lead time

First article: 1–3 weeks
Production: 2–6 weeks per release

What would it cost?

The builder's estimator on a representative plate. Change a size, the quantity or the material and the price updates.

All-in price per part (tooling and setup amortized) by order quantity. Budgetary.

Plate · CNC machining

$43.90per part, all-in, at 50 pcs

Order total $2,193

Tooling: None; no hard tooling
Piece price: $33.10; before setup + tooling
Lead time: 5–10 days; to first production

Size

Drag a row to adjust · click to type

Length

120

Width

80.0

Thickness

6.00

Material

Design checks pass

Open in builder

Budgetary estimate for a representative part. Firm quotes come from principals after drawing review.

How does it work?

6 steps from drawing to production parts.

1
Quote and DFM review
The model and drawing are reviewed for tool access, setups, and tolerances that drive cost.
2
Programming and fixturing
A CAM programmer writes toolpaths and designs fixtures or soft jaws that hold the part repeatably.
3
Saw and prep stock
Bar, plate, or tube is saw cut to blank length, or castings and forgings are received and staged.
4
Machining
Mills, lathes, and multi-axis centers remove material in one or more setups. Probing and in-process checks hold critical features.
5
Deburr and inspect
Edges are deburred, and parts are measured with a CMM, gauges, or optical systems against the drawing.
6
Finish
Parts are anodized, plated, heat treated, or passivated as specified, then packed.

When is cnc machining the right call?

Best for

Prototypes and production runs without hard tooling
Tight-tolerance bores, faces, and threads
Finish machining of castings and forgings
Cut-to-length bar, tube, and structural blanks by production sawing
Metals and engineering plastics such as acetal and PEEK

Pick something else when

Small round parts over about 10,000 a year: screw machining is cheaper
Plastic parts over about 5,000 a year: use plastic injection molding
Complex metal housings at volume: die casting plus finish machining costs less
Thin sheet enclosures and brackets: use sheet metal fabrication

Materials

23 materials principals run in cnc machining. Pick one for design rules, finishes and an estimate in that material.

Design rules that keep the price down

Full cnc machining design guide CNC milling CNC turning

At least 1/3 of cavity depth; 0.030 in (0.8 mm) minimum
Radius internal corners
Round tools cannot cut sharp inside corners, and larger radii allow larger, faster tools.
Depth no more than about 4× pocket width
Limit pocket depth
Deep pockets need long tools that chatter and cut slowly.
0.030 in (0.8 mm) in metal; 0.060 in (1.5 mm) in plastic
Minimum wall thickness
Thin walls vibrate, deflect, and lose tolerance.
About 4× diameter standard; up to 10× with peck drilling
Limit hole depth
Deep holes need special drills and slow cycles.
About 1.5× diameter for most tapped holes
Limit thread depth
Engagement beyond about 1.5× diameter adds little strength and costs cycle time.
Match standard drill, reamer, and tap sizes
Use standard hole sizes
Nonstandard sizes need interpolation or special tools.
Default to ±0.005 in (±0.13 mm) or ISO 2768-m
Tolerance only what matters
Tight general tolerances raise cost on every feature.
Put features on as few faces as possible
Minimize setups
Every added setup adds labor and stacks tolerance.

What drives the cost?

In order of impact.

1
Machine time
Cycle time is usually the largest cost. Deep pockets, small tools, and hard materials slow it down.
2
Setups
Each time a part is flipped or refixtured adds setup labor and a chance for error. Five-axis machines can cut the number of setups.
3
Tolerances and finish
Tighter tolerances and lower Ra need slower passes, extra operations, and more inspection.
4
Material
Stainless and titanium cost more per pound and cut several times slower than aluminum.
5
Quantity
Programming and first-article costs are fixed per job, so unit price drops quickly from 1 to 100 parts.
6
Secondary operations
Anodizing, plating, heat treat, and outside inspection add cost and calendar time.

Variants

3-axis milling: Vertical machining centers cut prismatic parts from one side per setup. The workhorse for plates, brackets, and housings.
5-axis milling: Tilting and rotating axes reach five sides in one setup for complex geometry and fewer fixtures.
CNC turning: Lathes and turn-mill centers make round parts from bar or chucked blanks, with live tooling for flats and cross holes.
Swiss turning: Sliding-headstock lathes machine long, slender parts with high precision. See screw machining for high-volume Swiss work.
Production sawing: Automatic band saws and circular cold saws cut bar, tube, and structural shapes to length as blanks or finished parts.
Finish machining of castings and forgings: Near-net castings and forgings are machined on critical faces, bores, and threads.

Where it shows up

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CNC machining questions

How much does CNC machining cost?

Cost is mostly machine time plus setup and programming. Typical US shop rates run about $75–$150 per hour for 3-axis milling and more for 5-axis. A single prototype carries all the setup cost, so unit price usually drops sharply by 25–100 pieces.

What tolerances can CNC machining hold?

Most shops hold ±0.005 in (±0.13 mm) as a standard tolerance. Critical features commonly hold ±0.001 in (±0.025 mm), and ±0.0002 in (±0.005 mm) is possible with grinding or temperature-controlled finishing. Each tighter step adds cost.

What is the minimum order for CNC machined parts?

There is no tooling, so one part is possible. Most production shops quote better per-part pricing from 25–100 pieces, where setup and programming spread out.

How long does CNC machining take?

Simple prototypes can ship in 1–2 weeks. Production runs typically take 2–6 weeks, depending on material, finishing, and machine loading.

When should I switch from machining to casting or forging?

When annual volume passes a few thousand parts and much of the stock is being cut away, a near-net casting or forging plus finish machining usually costs less. The breakeven depends on tooling cost, material removal, and tolerance needs.

What is production sawing?

Production sawing is cutting bar, tube, and structural shapes to precise lengths on automatic band saws or circular cold saws. It supplies blanks for machining, forging, and fabrication, or finished cut-to-length parts.

Quote cnc machining today.

Drop a STEP file for an instant estimate and DFM check. A rep routes the RFQ to principals who run this process every day.

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Production machining, turning, and sawing

Where it pays off

1101001k10k100k1M+