Buyer guide

CNC Processing Quotes and Costs Explained

A quote is not a price list. It is a shop's estimate of machine hours, setup, material and risk. This guide breaks down what sits inside CNC processing quotes and costs, which inputs change them, and how to compare two bids that look nothing alike.

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CNC processing quotes and costs for 5 axis machining

On this page

1
What drives a CNC quote
2
What moves CNC processing costs up or down
3
What actually sits inside CNC processing quotes and costs
4
How part geometry changes the number
5
Material choice and machining cost
6
Quantity, lead time and the method switch
7
How to compare suppliers and their quotes
8
Step by step: build an RFQ that gets a usable quote

Key takeaways

What drives a CNC quote

Machine time rules the totalSetup, tool changes and cycle time usually outweigh material on small runs.

Complexity beats sizeFine features, thin walls and tight tolerances add more cost than a large simple part.

Quantity changes the methodA 5-piece order is machined; a 5,000-piece order is machined differently or cast.

Material price is volatileTitanium and Inconel move more than 6061 aluminium, so quotes expire faster.

Every quote needs an expiry dateAsk how long the number holds and what makes it change.

Cost drivers

What moves CNC processing costs up or down

Use this to sanity-check a bid before you ask detailed questions.

Cost driver	Low-cost side	High-cost side
Part size	Fits a 500 × 500 × 450 mm envelope	Needs 4,000 mm travel
Tolerance	±0.05 mm general	±0.005 mm on every feature
Setup count	Two setups, one fixture	Five setups, custom fixtures
Feature count	Straight pockets and holes	Deep ribs, thin walls, 3D contours
Material	6061-T6 aluminium	Ti-6Al-4V or Inconel
Quantity	10 to 50 parts	1 piece, then 10,000 pieces
Finish	As machined, Ra 1.6–3.2 μm	Hardcoat anodize plus polishing
Inspection	Sample check	100% inspection with report

The bottom line on CNC processing quotes and costs

Price the process, not the part number. Send a complete RFQ, ask for setup and cycle time as separate lines, and match the shop's certifications and machine capacity to your industry. Do that and comparing quotes becomes a short conversation.

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Cost anatomy

What actually sits inside CNC processing quotes and costs

A machining quote is built from four lines: setup, cycle time, material, and outside work. Setup is the hours a machinist spends reading the drawing, building a fixture and proving the first article. Cycle time is the cutting hours multiplied by the machine rate. Material is bar stock or plate plus the drop you pay for but never use. Outside work covers heat treat, plating and anodizing.

On a 10-piece aluminium bracket, setup and programming can be half the bill. On a 10,000-piece run, cycle time dominates and setup almost disappears. That is why two shops can quote the same part 40% apart without either being wrong.

Machine hour rates vary with the machine, not the part. A 3-axis mill costs less per hour than a simultaneous 5-axis center because the machine itself costs more and the programmer needs more time. If your part has features on five faces, expect a 5-axis rate.

Ask for the quote broken into those four lines. A shop that cannot separate setup from cycle time is guessing, and you will pay for the guess.

1
SetupFixture build, first-article prove-out, tool presetting.
2
Cycle timeRoughing, semi-finish, finish, in-process checks.
3
MaterialStock size, drop allowance, certified mill test report.
4
Outside workHeat treat, plating, anodizing, laser marking.

Geometry

How part geometry changes the number

Long straight cuts remove material fast. Curved surfaces, deep pockets and thin walls do not. A 5-axis toolpath that keeps the tool engaged can cut a sculpted surface in one pass, but the programmer spends hours verifying collision clearance first. That time lands in the quote.

Wall thickness matters more than overall size. A 200 mm part with 1 mm walls will chatter, so the shop slows the feed, adds supports or machines it in two operations. A 400 mm part with 8 mm walls may run in one setup at full speed.

Deep holes and deep pockets need long tools. Long tools deflect, so the machinist reduces depth of cut and the cycle stretches. A hole 8× diameter deep is routine; 20× diameter deep needs peck drilling, a pilot hole and extra time.

If your design allows a 3-axis setup instead of a 5-axis one, say so. Shops will use the simpler route when the drawing permits it, and the quote drops.

1
Thin wallsBelow 1.5 mm on aluminium, expect slower feeds and extra support.
2
Deep pocketsDeeper than 4× tool diameter needs a longer, slower toolpath.
3
Tight radiiA corner radius under 2 mm forces a small tool and many passes.
4
UndercutsFeatures a 3-axis tool cannot reach push the part to 4- or 5-axis.

Material

Material choice and machining cost

Aluminium 6061 and 6061-T6 cut fast, hold tolerance well and cost little. They are the default for prototypes and functional parts. 7075 is stronger but gummier, so feeds drop and tool wear rises.

Stainless 303 machines cleanly; 304 and 316 work-harden and need slower speeds and more coolant. 17-4PH adds a heat-treat step that must be scheduled after roughing, which adds days, not just dollars.

Titanium Ti-6Al-4V removes heat poorly. Cutting speeds can be a fifth of aluminium, tool life is short, and the shop may need through-spindle coolant. Inconel is worse: it work-hardens at the surface and can wear out a carbide insert in minutes.

Plastics are not automatically cheap. POM and ABS machine easily, but PEEK and carbon fibre need sharp tooling, slow feeds and dust control. The material price per kilogram is often the smaller part of the bill.

1
Easy group6061, 6063, 303 stainless, brass C36000, POM.
2
Medium group7075, 304, 4140, 17-4PH, titanium Grade 2.
3
Hard groupTi-6Al-4V, Inconel, hardened tool steel, carbon fibre.

Volume

Quantity, lead time and the method switch

Unit price falls as quantity rises because setup is spread over more parts. The drop is steepest between 1 and 50 pieces, then flattens. Between 500 and 5,000 pieces, a machined part and a cast part can cross over on total cost.

Lead time is a separate line from cost. A shop with spare capacity can start production within 24 hours and ship parts in 3–5 days. A shop running at 95% load will quote a longer date or a higher price for priority. Ask which one you are buying.

Rush work is not free. Overtime, tooling airfreight and re-sequencing other jobs all cost money. If your schedule is flexible, say so and let the shop quote a standard date. That is often the cheapest lever you have.

For repeat orders, ask what the shop would change to cut cost. A small design change, a looser tolerance on a non-critical feature, or a standard stock size can take 10–20% out of a repeat run.

1
1 to 50 piecesSetup dominates; optimise the drawing, not the cycle.
2
50 to 500 piecesFixtures pay for themselves; ask for a dedicated workholding plan.
3
500 to 10,000+Compare machining against casting or metal injection moulding.

Supplier

How to compare suppliers and their quotes

Two quotes for the same drawing are only comparable if they cover the same scope. Check whether the price includes material certification, first-article inspection, finishing and packaging. A low number that excludes anodizing is not a lower price, it is a partial price.

Certifications tell you which markets a shop can serve. ISO 9001:2015 covers general quality systems. IATF 16949:2016 is required for automotive production. ISO 13485:2016 applies to medical devices. ISO 27001:2022 covers information security, which matters if your drawings are confidential.

Ask how inspection is handled. A shop that inspects 100% before shipment and can send reports on request is easier to qualify than one that samples. Ask what measuring equipment is used and whether it is calibrated.

Finally, check capacity against your part. A shop with 127 CNC machines, 16 simultaneous 5-axis centers and a 4,000 mm maximum processing size can take large or complex work that a small job shop cannot. Match the shop to the part.

1
ScopeMaterial, machining, finish, inspection, packaging, freight.
2
CertificationsMatch the certificate to your industry, not to the website banner.
3
CapacityMachine size, axis count and spindle hours available per week.
4
ConfidentialityNDA on request; secure uploads for drawings.

RFQ checklist

Step by step: build an RFQ that gets a usable quote

Follow these steps in order. Skipping one usually produces a quote you cannot compare.

1
Send a complete 3D model and a 2D drawingSTEP or IGES for geometry, PDF for tolerances, datums and surface finish. A model alone leaves tolerance open, so shops assume the loosest value.
2
State the quantity and the annual volumeGive first-order quantity plus expected yearly usage. A shop prices a 10-piece order differently from a 10,000-piece program.
3
Mark critical features onlyApply ±0.005 mm where it matters and general tolerances elsewhere. Tightening every dimension can double cycle time for no functional gain.
4
Name the material and temper6061-T6 is not the same as 6061-O. Include the standard, for example ASTM B209 or SUS630, so the shop quotes the right stock.
5
Specify the finish and its standardClear anodize per MIL-A-8625 Type II, or Ra 0.8–1.6 μm as machined. Vague finishes get quoted as the cheapest option.
6
State inspection and documentation needsFirst-article report, material cert, or full dimensional report. Documentation adds time and must be priced.
7
Give the delivery date you actually needA realistic date lets the shop use standard scheduling. A compressed date forces overtime and raises the price.
8
Ask for a cost breakdownRequest setup, cycle, material and outside work as separate lines. That is what makes two quotes comparable.

FAQs

CNC processing quotes and costs: common questions

Why did my quote change after I sent the same drawing?

Most changes come from material price or scope, not from the machine rate. Aluminium and titanium stock move with the market, so a quote issued weeks ago may no longer hold.

The other common cause is a detail that was not specified the first time, such as a finish, a material certificate or an inspection report. Once those are added, the price rises.

Is a lower hourly rate always cheaper?

No. A shop with a low rate but slow programming and long setups can cost more overall than a higher-rate shop that runs the part in one setup with a proven fixture.

Compare the total quoted price and the lead time, then ask what each shop would change to reduce cost. The answer tells you how well they understand the part.

What tolerance should I put on a CNC drawing?

Put tight tolerance only on the features that control function, such as bearing bores, mating faces and locating holes. Use general tolerances elsewhere.

GreatLight machines to ±0.005 mm when the drawing requires it, but applying that to every dimension adds inspection time and cost without improving the part.

When does casting beat machining on cost?

Roughly when annual volume passes a few thousand pieces and the geometry has thick sections that would be slow to cut from solid. Tooling cost must be amortised over that volume.

Below that volume, machining usually wins because there is no tooling and design changes stay cheap.

How do I keep my design confidential during quoting?

Ask for an NDA before you send files, and use a supplier with a documented information security system. GreatLight holds ISO 27001:2022 and signs NDAs on request.

Send only what the shop needs for the quote. A STEP file and a drawing are usually enough; full assemblies are not.

What lead time should I expect for a machined part?

With a complete RFQ, a quotation and DFM analysis can come back within 12 hours, and production can start within 24 hours. Standard parts then ship in 3–5 days.

Times stretch when material is not in stock, when a finish is outsourced, or when the shop is fully loaded. Build a buffer into your schedule rather than paying for rush work.