Get CNC Quotation Tips That Hold Up on the Shop Floor
This page is for design engineers and purchasing teams who need a number they can trust, not a fast guess. We walk through the RFQ package, the drawing details that actually move price, and how to read a quote line by line. After reading, you should know which parts of your submission to fix before you send it.
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Key takeaways
Build the RFQ Package Before You Ask for a Number
Most slow quotes are not a supplier problem. They are a package problem. When an estimator opens a folder and finds one PDF with a front view and no material callout, the only honest answer is a range, and ranges get rounded up. Send the full set and the first reply can be a real number.
Start with a native 3D file: STEP, IGES or SLDPRT. STEP AP214 is the safest neutral format because it carries solid geometry cleanly across CAD systems. Then add a 2D drawing that carries the information the model cannot: datums, GD&T frames, thread callouts, surface finish symbols and inspection requirements.
Material matters more than most buyers expect. 6061-T6 machines fast and holds tolerance well. 304 stainless work-hardens and needs slower feeds. Ti-6Al-4V and Inconel eat tool life, so the same part in titanium can cost several times the aluminum version. Name the alloy and temper, not just "aluminum".
Quantity is the last mandatory field. Tell us whether this is one prototype, a 50-piece bridge run, or a 10,000+ part production order. We run no minimum order quantity, so one piece is fine, but the quoting logic changes completely between those three cases.
- 1GeometrySTEP, IGES or SLDPRT of the finished part, plus any stock model.
- 2DrawingDatum scheme, GD&T, threads, finish symbols, critical dimensions.
- 3MaterialAlloy and temper, for example 7075-T6 or 17-4PH (SUS630).
- 4Quantity and finishOrder count plus anodizing, plating, coating or laser marking.
Get CNC Quotation Tips on Tolerance, Finish and Setup Count
Tolerance is where price is won or lost. General machining at ±0.1 mm is straightforward on any of our 27 three-axis machines. Push to ±0.005 mm and the part needs temperature-stable cutting, a probe check, and often a dedicated fixture. If a bore only needs to clear a bolt, do not call it out at ±0.005 mm.
Apply tight tolerance only to the features that function. A common pattern we see: a bearing seat at ±0.005 mm surrounded by bracket holes also marked ±0.005 mm. Relaxing the bracket holes to ±0.1 mm can remove an entire finishing operation, and the part still works.
Surface finish behaves the same way. As-machined at Ra 1.6–3.2 μm comes off the tool. Ra 0.8–1.6 μm needs a controlled finishing pass. Ra 0.2–0.8 μm usually means a secondary process such as fine tumbling or polishing. Each step down adds time per surface, not per part.
Setup count is the hidden cost most RFQs miss. A part that can be reached from five sides in one setup on a 5-axis center avoids three refixtures on a 3-axis machine. Fewer setups means less stack-up error and a shorter route. If your part has features on four or more faces, say so in the RFQ so the estimator can quote the right machine.
- 1General tolerance±0.1 mm is fine for brackets, covers and non-mating holes.
- 2Precision tolerance±0.005 mm belongs on bearing seats, spigots and sealing faces.
- 3As-machinedRa 1.6–3.2 μm, no extra operation.
- 4Fine finishRa 0.8–1.6 μm or Ra 0.2–0.8 μm adds a finishing pass or secondary step.
Get CNC Quotation Tips: How to Read the Number You Receive
A CNC quote is a routing document, not a price tag. The useful ones break out material, machining time, finishing and inspection. If yours is a single lump sum with no notes, ask for the assumptions. That question costs nothing and prevents a re-quote after award.
Look for a DFM note. Our quotations come with a free DFM analysis and we flag thin walls, deep pockets, sharp internal corners and features that need a custom cutter. A corner radius smaller than the cutter diameter cannot be machined at full depth; it needs EDM or a design change. Catching that before cutting saves a revision.
Check the lead-time line against your build schedule. Our standard path is quotation and DFM within 12 hours, production start within 24 hours, and parts shipping in 3–5 days. Complex parts that need fixture design or a second operation take longer, and a supplier who hides that in a vague date is not doing you a favor.
Finally, compare like for like. Two quotes for the same part often differ because one assumes 6061-T6 and one assumes 6082, or one includes anodizing and one does not. Normalize material, finish, inspection level and quantity before you decide.
- 1Cost breakdownMaterial, machining, finishing, inspection as separate lines.
- 2DFM notesFlagged features, suggested radius changes, wall thickness warnings.
- 3Lead timeSeparate lines for quote, production start and shipping.
- 4ExclusionsAnything not quoted, such as heat treat or third-party certification.
Seven RFQ Mistakes That Inflate a CNC Quote
The first mistake is sending a PDF only. Vector or raster, a 2D sheet leaves the third dimension to interpretation. Estimators add margin when they cannot measure the part in CAD.
The second is missing thread and callout standards. "M6" is different from "M6 × 1.0 6H". Specify the standard and the class, and note whether threads are cut or formed.
The third is inconsistent revision control. If the model is Rev C and the drawing is Rev B, we quote the more conservative of the two until you confirm. That is not padding; it is the only safe reading.
The fourth is leaving finish to the end. If anodizing is decided after the quote, the color, thickness class and masking requirements change the price. Say it up front. The fifth is hiding the annual volume. A prototype quote and a production quote use different fixtures, and knowing the ramp helps us quote the first article sensibly.
- 1No 3D modelForces geometric assumptions and added margin.
- 2Vague thread calloutsState standard, pitch and class, for example M6 × 1.0 6H.
- 3Mixed revisionsModel and drawing must carry the same revision letter.
- 4Undisclosed volumeTell us the prototype and production quantities together.
Questions That Separate a Real Quote from a Placeholder
Ask which machine will run the part. For a housing with features on five faces, a simultaneous 5-axis center in one setup is a different cost structure than three-axis with fixtures. We run 16 simultaneous 5-axis centers, 16 mill-turn centers and a Ø400 mm rotary table, and we can reach 4,000 mm on the largest travel.
Ask how the tolerance will be verified. A ±0.005 mm callout is a claim until someone states the method: in-process probing, a CMM check, or a gauge on a specific feature. We monitor in process and inspect 100% before shipment.
Ask what happens if the first article is out. A supplier with a clear rework path is safer than one who quotes lowest and negotiates later. Ask about the historical late-delivery rate too. Ours sits below 2%.
Certifications are worth checking against your industry. We hold ISO 9001:2015, IATF 16949:2016 for automotive, ISO 13485:2016 for medical devices, and ISO 27001:2022 for information security. That last one matters if your drawings are confidential. Uploads are secure and confidential, and an NDA is available on request.
- 1Machine assignmentWhich spindle, how many setups, what workholding.
- 2Verification methodProbing, CMM or gauge, and which features are measured.
- 3Nonconformance pathRework, re-quote or design change, decided before cutting.
- 4CertificationsMatch the supplier's scope to your industry requirements.
How to Prepare and Send a CNC RFQ
Follow these in order. Each step removes a reason for the estimator to guess.
- 11. Freeze the geometryFinish all modeling changes before export. Export STEP AP214 from the released revision. Do not send a model you plan to edit tomorrow; a quote against a moving model is worthless.
- 22. Write the 2D drawingSet a datum scheme, then add GD&T only where function requires it. Mark critical dimensions clearly and leave non-critical features to the general tolerance block, typically ±0.1 mm.
- 33. Specify material and temperName the alloy and condition: 6061-T6, 7075-T6, 316L, 17-4PH (SUS630), Ti-6Al-4V. Add any certs you need, such as material certificate or RoHS.
- 44. Define finish and markingState the process and the class: clear anodize, hardcoat, electroless nickel, bead blast. For laser marking, keep character height at 1.5 mm or above so it stays legible.
- 55. State quantity and rampGive the first-article count and the expected annual volume. We quote from one piece to 10,000+ part runs with no minimum order quantity.
- 66. Add inspection requirementsSay whether you need a first article inspection report, dimensional report or material certs. We inspect 100% before shipment and provide reports on request.
- 77. Send the package and confirm the assumptionsUpload the model, drawing and spec sheet through the quote form. We return a quotation and free DFM analysis within 12 hours. Read the assumptions and reply if any are wrong.
What Changes the Quote and What Does Not
Use this to decide where to spend tolerance budget and where to relax it.
| Factor | Low-cost choice | Higher-cost choice | When to accept the cost |
|---|---|---|---|
| Tolerance | ±0.1 mm general | ±0.005 mm on selected features | Mating or sealing surfaces only |
| Surface finish | Ra 1.6–3.2 μm as-machined | Ra 0.2–0.8 μm polished | Sliding contact or optical seats |
| Material | 6061-T6 aluminum | Ti-6Al-4V or Inconel | Weight, heat or corrosion demand |
| Setup count | One 5-axis setup | Three 3-axis refixtures | Only if 5-axis travel cannot reach |
| Quantity | 10,000+ part run | Single prototype | First article or design validation |
| Finishing | As-machined | Anodize plus laser marking | Corrosion, branding or traceability |
| Inspection | Standard final check | Full dimensional report | Regulated or safety-critical parts |
A good quote starts with a complete package
Send the 3D model, the drawing with real tolerances, the material and temper, the finish, and both quantity figures. That one habit removes most of the back-and-forth and gets you a number you can build against.
CNC Quotation Questions Engineers Ask
What files do you need to quote a CNC part?
Send a native or neutral 3D model (STEP, IGES or SLDPRT), a 2D drawing with datums, tolerances and finish callouts, the material and temper, the quantity, and any post-processing such as anodizing or laser marking.
If you only have a sketch or a sample part, send it anyway. We can reverse-engineer the geometry, but the quote will carry a note about what was assumed.
Does a tighter tolerance always cost more?
Not always, but it usually changes the process. If a feature at ±0.005 mm can be probed in the same setup, the added cost may be small. If it forces a separate finishing operation or a custom fixture, the cost is real.
The practical move is to tighten only what mates, seals or slides, and leave the rest at the general tolerance.
Can you recommend a material if I only know the function?
Yes. Give us the functional requirements: strength, weight, corrosion resistance, thermal or electrical conductivity, and budget. Our engineers will suggest options and explain the cost of each.
For example, 6061-T6 covers most structural brackets, 7075-T6 suits high-strength aerospace parts, and 316L is the default for corrosive or medical environments.
How fast will I get the quote?
A quotation and free DFM analysis come back within 12 hours for a complete RFQ. Complex parts that need fixture design or a full DFM review can take longer.
We would rather send an accurate quote a few hours later than a fast number that changes after award.
Is there a minimum order quantity?
No. We quote from a single prototype up to 10,000+ part runs. The process and fixtures change with quantity, so tell us both the first-article count and the expected annual volume.
Will you sign an NDA before I send drawings?
Yes. Uploads are secure and confidential, and we can sign a non-disclosure agreement before you share files. Ask for it in your first message and we will send our standard NDA.
Send your RFQ and get a quote plus DFM notes in 12 hours
Upload your model and drawing. We reply with a quotation, a free DFM analysis, and a clear list of the assumptions behind the number.
12-hour quoteFree DFM analysis100% inspectionNDA on request
More machining notes
We publish setup notes, tooling trials and inspection data from the factory floor.
