CNC Machining Pricing Guide

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  What moves a CNC price
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  What each line item on a CNC quote covers
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  The 6 cost drivers behind every CNC quote
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  How tolerance and surface finish change the price
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  3-axis, 4-axis and 5-axis pricing compared
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  How to compare CNC machining suppliers, not just prices
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  Step by step: how to get a quote you can compare

A CNC price is not a single number pulled from a table. It is the sum of material, setup, cycle time, tooling, inspection, finishing and programming, divided by the batch size. When two suppliers quote the same part and the numbers differ by 40%, one of those lines is being handled differently. Ask which one.

Machine time is usually the largest share. On a simple aluminum bracket run of 100 parts, cycle time and setup can account for more than half the unit price. On a titanium impeller with 5-axis surfacing, that share climbs higher because the toolpaths are longer and the feeds are slower.

Quantity has an outsized effect on the first batch. Setup is a fixed cost. Split it across 10 parts and each one carries a heavy load. Split it across 500 and the setup nearly disappears from the unit price. This is why prototype pricing and production pricing for the same geometry can differ by 3× or more.

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  Material shapeBuying stock close to finished size cuts both material cost and cycle time.
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  Feature depthA pocket 4× deeper than its width needs long-reach tools and slower passes.
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  Datum countEach new datum usually means another setup or a fixture.

General machining tolerance is achievable at normal feeds and speeds. Tightening a critical bore to ±0.005 mm changes the process. The shop has to leave stock for a finishing pass, control thermal growth, and measure the result rather than assume it. That extra pass and extra measurement show up on the quote.

Surface finish works the same way. An as-machined surface at Ra 1.6–3.2 μm comes off the cutter with no extra work. Pushing to Ra 0.8–1.6 μm usually means a slower finishing pass with a smaller stepover. Pushing to Ra 0.2–0.8 μm may require a separate operation, a different tool, or a polishing step after machining.

The practical move is to tolerance only what functions. A mounting face that bolts to a plate does not need the same callout as a bearing seat. Engineers who mark up a drawing with a single blanket tolerance across all dimensions routinely pay for precision in places that never touch another part.

Finishing adds a separate cost layer. Anodizing, electroless nickel, zinc plating, powder coating and black oxide are priced per part or per rack, and the rack cost does not shrink with small batches. Masking threads and mating surfaces adds labor. Laser marking has its own constraint: minimum character height 1.5 mm, so plan the marking area before the drawing is frozen.

The axis count is a pricing decision, not a quality badge. A part with features on three orthogonal faces can be machined on a 3-axis mill with two or three setups. The same part on a 5-axis machine might run in one setup, which removes re-fixturing, reduces handling errors, and shortens the total time in the shop.

The crossover point depends on how many faces carry features. One or two faces: 3-axis is usually cheaper. Three or four faces with tight positional relationships: 5-axis starts to win, because the alternative is multiple fixtures and repeated datum transfers that each add error and labor.

Five-axis work is not automatically expensive. Simultaneous 5-axis surfacing for an impeller or a contoured aerospace bracket takes long toolpaths and skilled programming, so it costs more. Indexed 5-axis, where the table rotates and locks between operations, is closer in cost to 4-axis work and covers a lot of real parts.

For large parts, size matters as much as axis count. GreatLight machines up to 4,000 mm maximum processing size, with travels including 4,000 × 400 × 150 mm and 750 × 1,150 × 550 mm. A part that fits one of those envelopes avoids the cost of splitting the job across two machines.

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  3-axisBest for prismatic parts with features on one or two faces.
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  4-axisAdds rotary work for cylindrical or wrapped features.
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  5-axisPays off when features sit on 3+ faces or need contoured surfacing.

A low quote from a shop with no inspection process is not a low price. It is a deferred cost. Before comparing numbers, confirm what each supplier includes: material certification, in-process monitoring, final inspection, and reports on request. GreatLight runs raw material checks, in-process monitoring and 100% inspection before shipment.

Certifications narrow the field fast. ISO 9001:2015 covers general quality systems. IATF 16949:2016 matters for automotive and EV work. ISO 13485:2016 applies to medical devices. ISO 27001:2022 covers information security, which matters if your drawings are confidential. If a supplier cannot show the certificate that matches your industry, the price comparison is not apples to apples.

Lead time is part of the price. A quote that saves 15% but adds two weeks of waiting costs more than the difference in most programs. Ask for the quote turnaround, the production start window, and the shipping window separately. GreatLight returns a quotation and free DFM analysis within 12 hours, can start production within 24 hours, and ships parts in 3–5 days.

Minimum order quantity is the other hidden variable. Some shops quote a low unit price but require a 500-piece minimum. Others quote high for one piece because setup is not amortized. A supplier with no minimum order quantity, running from one prototype to 10,000+ part runs, lets you compare prototype and production pricing on the same geometry.