CNC alloy processing: how to quote without the back-and-forth
A working guide for engineers and buyers who need a real number, not a range. We cover the seven steps that turn a drawing into a quote, the data that decides whether a supplier can hold ±0.005 mm, and the cost drivers that actually move the price on aluminum, titanium, and nickel alloys.
Key takeaways
What a CNC alloy processing quote is built from
Most engineers ask for a number before they know what the supplier has to do to produce it. A quote for CNC alloy processing is a stack of decisions: the blank, the fixture, the number of setups, the cutting strategy, the inspection plan, and the finish. Change any one of them and the price moves.
Material behaves differently on the spindle. Aluminum 6061 and 7075 cut fast and hold tight tolerances with light fixturing. Titanium TC4 and Inconel work-harden at the cut and pull heat into the tool, so feeds drop, tool life shortens, and the same geometry can take two to three times longer than in aluminum. That difference shows up in the quote before any feature is counted.
Geometry is the second input. A part with one flat face and a few drilled holes can run on a three-axis mill with a vise. A part with pockets on five sides, thin ribs, or an undercut needs a five-axis center or a mill-turn setup. The quote reflects the machine, not the drawing's page size.
- 1Blank size and stock formPlate, bar, forging, or casting changes both cost and lead time.
- 2Tolerance class±0.005 mm on a critical bore costs more than ±0.05 mm on a bracket.
- 3Surface finishAs-machined at Ra 1.6–3.2 μm is the baseline; Ra 0.2–0.8 μm needs extra passes.
The data that gets you an accurate number
A supplier cannot quote what it cannot see. The fastest RFQs we receive include a STEP or Parasolid model, a 2D drawing with GD&T, the alloy grade, the quantity, and the tolerance class. When any of those is missing, the supplier either guesses or comes back with questions, and both add days.
Callouts matter more than file format. A drawing that says "critical bore Ø12 H7" tells the shop where to spend inspection time. A drawing that marks every dimension as ±0.01 mm tells the shop nothing useful and forces a conservative quote. Mark only the features that carry function.
Quantity changes the method. One prototype and a 10,000-part run are not the same quote. Low volume favors three-axis mills, soft jaws, and manual deburring. High volume justifies fixtures, probing, and sometimes a five-axis cell running lights-out. Tell the supplier both numbers if you expect to scale.
Finish and documentation belong in the first message. Anodizing color, plating thickness, laser marking height, first-article reports, and material certificates all add line items. Hiding them until after the quote is the most common reason a price changes.
Cost drivers that move a CNC alloy processing quote
Setup count is the driver most engineers underestimate. Every new orientation needs a fixture, a touch-off, and a first-part check. A part that looks simple on paper but needs four sides machined can cost more than a part twice its size that runs in one five-axis setup.
Tool access decides cycle time. A pocket 4× deeper than its width forces long-reach tooling, light radial engagement, and slow feed. The same pocket at 2× depth runs at normal parameters. When you can, keep depth-to-diameter ratios under 4 and corner radii above one-third of the tool diameter.
Thin walls and tight tolerances fight each other. A 1 mm wall on a 200 mm aluminum part will move under cutting force. The shop has to reduce depth of cut, add semi-finish passes, and sometimes stress-relieve the blank first. That is real time, and it appears in the quote.
Inspection scales with tolerance, not with part count. Holding ±0.005 mm on a bore means CMM time, temperature control, and possibly a gauge. A general-tolerance bracket may only need calipers and a visual check. State which features need reports so the shop quotes the right inspection level.
When the quote looks high, check these first
A high number is usually a signal, not a mistake. Before pushing back, read the assumptions. Many quotes carry a note that says the price assumes a specific tolerance, a specific finish, or a specific quantity. If your requirement differs, the price will too.
Long cycle time on a simple shape often means the shop cannot reach the feature in one setup. Ask whether a five-axis center changes the plan. On complex alloy parts, moving from three setups to one can cut labor by more than the hourly rate difference.
Material cost is worth a second look on titanium and nickel alloys. Stock removal ratio matters: a part cut from a 100 mm plate when a 60 mm plate would do wastes both material and cycle time. Redesigning the blank can be cheaper than negotiating the rate.
Finally, check whether inspection is priced at the level you asked for. If the drawing shows general tolerances everywhere, a quote that includes full CMM reports on every part is carrying cost you did not request. Match the inspection plan to the function.
7 steps to a clean quote
Follow these in order. Skipping step 2 or 3 is the most common cause of a re-quote.
- 1Pick the alloy before you pick the shopChoose a grade that matches the load, the environment, and the finish plan. 6061-T6 for general parts, 7075 for high strength, 17-4PH for corrosion plus strength, TC4 where weight matters. Name the grade and temper in the RFQ.
- 2Clean the model and the drawingExport a single solid STEP file. Remove construction geometry, hidden bodies, and thread cosmetics. On the 2D drawing, mark only functional tolerances and datum features. A tidy package cuts quote time to hours.
- 3State quantity and target tolerance classGive prototype quantity and production quantity. State whether general tolerances are acceptable or whether specific features need ±0.005 mm. This single line often changes the machine selection.
- 4List finish and documentationAnodizing type and color, plating thickness, bead blasting, laser marking with 1.5 mm minimum character height. Add first-article report, material cert, and inspection report requirements here, not later.
- 5Ask for DFM feedback with the priceA good shop returns a quote plus notes: a radius that should grow, a wall that should thicken, a tolerance that can relax. At GreatLight this analysis comes back within 12 hours with the quotation.
- 6Compare quotes on the same basisCheck that every supplier quoted the same alloy, the same tolerance class, the same finish, and the same inspection level. A low number that excludes anodizing is not a lower price.
- 7Lock the revision before productionConfirm the drawing revision, the material cert, and the inspection plan in writing. Production can start within 24 hours of approval, and parts typically ship in 3–5 days.
What changes the quote, and by how much
Order-of-magnitude effects seen on typical alloy parts. Use it to sanity-check a quote, not to predict a price.
| Variable | Low-cost case | High-cost case | Why it moves |
|---|---|---|---|
| Alloy | 6061-T6 aluminum | Inconel or TC4 titanium | Cutting speed and tool life |
| Setup count | One orientation | Four or more sides | Fixtures, touch-offs, checks |
| Wall thickness | Above 2 mm | Below 1 mm | Deflection and extra passes |
| Depth-to-diameter | Under 3× | Over 5× | Long-reach tooling, slow feed |
| Tolerance | General ±0.1 mm | ±0.005 mm on bores | CMM time and gauges |
| Finish | As-machined Ra 1.6–3.2 μm | Ra 0.2–0.8 μm | Extra semi-finish passes |
| Quantity | 10,000+ parts | One prototype | Setup amortization |
Send the drawing once, get the number back
A complete RFQ with alloy, quantity, tolerance class, and finish returns a quotation and DFM notes within 12 hours. Missing data is what stretches a quote into a week, not the machining itself.
Questions engineers ask before quoting
How fast can I get a quotation for CNC alloy processing?
For standard parts with clear models and drawings, the goal is a quotation and free DFM analysis within 12 hours. Complex geometry, multiple alloys, or heavy documentation requirements can take longer because the shop needs to model the setups and verify tool access.
If your RFQ is missing the alloy grade, quantity, or tolerance class, expect a question back before a number. Sending the full package up front is the fastest path.
Do you have a minimum order quantity?
No. We run from one prototype to 10,000+ part runs on the same equipment. Low volume typically uses three-axis mills and soft jaws; higher volume justifies dedicated fixtures and probing.
What tolerance can you hold on alloy parts?
We hold ±0.005 mm (±0.0002 in) where the drawing calls for it. That level needs a stable setup, temperature control, and CMM verification, so it should be reserved for functional features.
Surface finish ranges from Ra 0.2–0.8 μm on fine-finish features to Ra 1.6–3.2 μm as-machined.
Which alloys do you machine most often?
Aluminum 6061, 6061-T6, 2024, 5052, 5083, 6063, 6082, 7075, and ADC12; stainless 303, 304, 316, 316L, 420, 430, 431, 440C, and 17-4PH; steel 1018, 1045, 4130, 4140, 4340, and A36; copper and brass C101, C110, C36000; titanium TA1, TA2, TC4, plus Inconel and magnesium AZ31B or AZ91D.
How do you handle confidential drawings?
Uploads are secure and confidential. We can sign an NDA on request before any file is exchanged, and access to customer data is controlled under our ISO 27001:2022 procedures.
What certifications support the quality plan?
We hold ISO 9001:2015, IATF 16949:2016, ISO 13485:2016, and ISO 27001:2022. Every part is inspected before shipment, with raw material checks, in-process monitoring, and final inspection. Inspection reports are available on request.
Quote your alloy part today
Upload a STEP file and a drawing. We review the geometry, flag DFM issues, and return a quotation with the assumptions written down.
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