1. What Is a CNC Machining RFQ?
An RFQ (Request for Quotation) for CNC machining is a structured request that asks a manufacturer to quote unit price, tooling cost (if any), lead time, and manufacturability considerations for one or more parts. In most B2B manufacturing workflows, the RFQ is the starting point for supplier selection and production planning.
Unlike consumer purchases, CNC machining quotations depend heavily on technical details. A supplier cannot quote accurately without knowing:
- What the part is (geometry + features)
- What the part is made of (material grade + condition)
- How many you need (prototype vs batch vs annual volume)
- How precise it must be (tolerances + GD&T)
- How it must look/perform (surface finish, coating, hardness)
- How it will be inspected (inspection reports, FAI, CMM, etc.)
- When and where it must arrive (delivery terms + deadline)
If you’ve ever felt that CNC suppliers “quote too high,” “ask too many questions,” or “take too long,” the root cause is usually not the supplier—it’s the RFQ lacking critical information.
2. Why Most CNC RFQs Get Slow or Wrong Quotes
Suppliers price CNC machining by evaluating manufacturing risk. When your RFQ is incomplete, the supplier must guess—then protect themselves by adding margin or delaying until questions are answered. This is why a weak RFQ often leads to:
- Slow responses: the supplier must request missing details.
- Unrealistic quotes: pricing is based on assumptions you didn’t approve.
- Higher prices: risk premium is added for unclear tolerances, material, or finish.
- Production issues later: what you expected and what was quoted diverge.
Common RFQ problems include:
- No drawings or only screenshots instead of dimensioned PDFs.
- Missing tolerances (“standard tolerance” means different things to different shops).
- Material unspecified (e.g., “aluminum” without grade like 6061-T6).
- Quantity unclear (prototype price vs production price can differ dramatically).
- No surface finish requirement (raw machined vs anodized vs bead-blasted changes cost).
- No inspection requirements (CMM report, FAI, PPAP-like docs add time and cost).
- No delivery terms (EXW/FOB/CIF, destination, and deadlines affect lead time).
A good RFQ eliminates ambiguity. That’s how you get accurate quotes quickly—and avoid expensive re-quotes.
3. The 7 Essential Elements of a High-Quality CNC RFQ
3.1 Part Drawings (2D + 3D)
This is the single most important RFQ item.
- 2D drawing (PDF): dimensions, tolerances, threads, notes, critical features
- 3D model (STEP/IGES): helps CAM programming and reduces misinterpretation
Best practice: Use consistent file naming: PartName_PN-001_RevA.pdf + PartName_PN-001_RevA.step. If the revision changes, update both files to prevent mismatched quotes.
Tip for accurate pricing: If only a few dimensions are critical, define a general tolerance (like ISO 2768) and then clearly label critical features. Over-tolerancing is one of the fastest ways to inflate price.
3.2 Material Specification (Grade + Condition)
Never write just “steel” or “aluminum.” Always specify:
- Material grade: e.g., Aluminum 6061-T6, 7075-T6, SS304, SS316, 4140, POM, PTFE
- Condition/temper: e.g., T6, annealed, hardened
- Allowed equivalents: optional, but can reduce lead time and cost
Example: Material: Aluminum 6061-T6 (equivalent acceptable: 6082-T6).
3.3 Quantity (Now + Future)
Quantity drives machine time amortization, setup cost allocation, and inspection strategy.
- Prototype quantity: 1–10 pcs
- Trial batch: 20–200 pcs
- Production plan: monthly/quarterly/yearly volume (if available)
Why this matters: A quote for 5 pcs and a quote for 500 pcs can differ by multiples. If your RFQ includes a credible production forecast, suppliers can offer better pricing and capacity commitment.
3.4 Tolerances & Critical Features
Tolerances determine machining difficulty, inspection time, and scrap risk. Clear tolerancing yields faster quotes and fewer “hidden assumptions.”
Include:
- General tolerance: e.g., ISO 2768-m (or a company standard)
- Critical dimensions: list or highlight on drawing (±0.02 mm, ±0.01 mm, etc.)
- GD&T requirements: flatness, perpendicularity, position, etc. if needed
- Fit requirements: press-fit, slip-fit, bearing fit, thread class
Practical note: If only 2–3 dimensions are critical, don’t apply ±0.01 mm to the entire part. Target tolerances only where function demands it.
3.5 Surface Finish & Post-Processing
Many RFQs fail because surface finish is assumed. Surface finish affects both appearance and performance, and it often changes the manufacturing route.
Specify clearly if you need:
- Surface roughness (Ra): e.g., Ra ≤ 1.6 μm on functional faces
- Anodizing: Type II / Type III, color, thickness
- Plating: zinc, nickel, chrome, etc.
- Bead blasting: matte texture requirement
- Heat treatment: hardness range and test method
Example: Finish: Black anodize Type II, thickness 10–15 μm; Ra ≤ 1.6 μm on marked surfaces.
3.6 Quality & Inspection Requirements
Inspection requirements strongly affect quote and lead time—especially for tight tolerances.
Common requirements:
- COA / material cert: proof of material grade
- Dimensional inspection report: key dimensions measured
- FAI (First Article Inspection): first-piece validation before production
- CMM inspection: for complex GD&T
- ISO certification: ISO 9001 as a baseline requirement
Important: If you need an inspection report, state which dimensions must be reported (all dims vs key dims). “Full inspection report” can be costly and slow unless truly necessary.
3.7 Delivery Terms, Lead Time, and Packaging
RFQs often ignore logistics—until it’s too late. Include:
- Delivery location: full address or city/port
- Incoterms: EXW / FOB / CIF / DDP (as applicable)
- Target lead time: e.g., 15 days for prototypes, 25–30 days for batches
- Packaging: protective packaging for anodized surfaces, anti-rust oil, foam separation
Tip: If lead time matters, ask suppliers to quote both standard lead time and expedited lead time so you can compare trade-offs.
4. Recommended RFQ Format (Supplier-Friendly)
A supplier-friendly RFQ is easy to read, easy to forward internally, and easy to quote without guessing. The best format is:
- One email summarizing key requirements
- Attachments containing drawings and models
- A simple RFQ table listing parts and quantities (optional but recommended)
If you have multiple parts, include an RFQ table like this:
| Part No. | Revision | Material | Qty | Finish | Notes |
|---|---|---|---|---|---|
| PN-001 | Rev A | Al 6061-T6 | 100 | Clear anodize | Critical: Ø10 H7 |
| PN-002 | Rev B | SS304 | 50 | Raw machined | Ra ≤ 1.6 on face A |
This approach reduces confusion and makes it easier for suppliers to respond with a clean, comparable quotation.
5. Copy-Paste CNC Machining RFQ Template
Use this template to get accurate quotes quickly. Replace the brackets with your details.
Subject: RFQ – CNC Machining Quote Request – [Project/Part Name]
Dear [Supplier Name/Team],
Please provide a quotation for CNC machining of the following part(s):
Part Name / Part No.: [PN-001 / Housing Block]
Drawings & 3D Models: Attached (PDF + STEP)
Material: [Aluminum 6061-T6] (equivalent acceptable: [optional])
Quantity: [e.g., 50 pcs prototype + 500 pcs production potential]
Tolerances: General tolerance [ISO 2768-m]; Critical dimensions: [±0.02 mm on marked features]
Surface Finish: [e.g., Black anodize Type II, 10–15 μm] / [Ra requirement if any]
Inspection Requirements: [COA + dimensional inspection report (key dims)]
Packaging: [e.g., protective packaging for anodized surfaces, no scratches]
Delivery Terms: [FOB Shanghai / CIF Hamburg / DDP New York]
Target Lead Time: [e.g., 3–4 weeks after PO]
Please include in your quotation:
Unit price and total price
Tooling/setup cost (if any)
Lead time and production capacity
Quotation validity
Any DFM feedback (cost-driving features, improvements)
Best regards,
[Your Name]
[Company]
[Phone/WhatsApp]
[Email]
Optional add-on (recommended): Ask suppliers to confirm manufacturability risks. One line can save weeks:
“Please advise if any features are difficult, cost-driving, or risky to machine, and suggest improvements.”
6. Pro Tips to Reduce Price and Lead Time
6.1 Don’t over-tolerance everything
Over-tolerancing is a hidden cost driver. If you apply tight tolerances to the entire drawing, the supplier must machine slower, inspect more, and accept higher scrap risk. A better strategy is to:
- Use a reasonable general tolerance
- Define only function-critical features as tight tolerance
6.2 Allow material equivalents (when acceptable)
If your design allows it, permitting equivalents can dramatically reduce lead time. For example, allowing 6082-T6 instead of only 6061-T6 (depending on region) may speed procurement.
6.3 Separate prototype RFQ and production RFQ
Prototype machining prioritizes speed and flexibility. Production prioritizes stability and cost efficiency. If you combine both in one unclear request, you may get mismatched pricing. State your plan clearly: prototype first, then production.
6.4 Provide an inspection scope
Instead of “full inspection,” specify:
- Key dimensions to report
- Measurement method if required (CMM, gauge, etc.)
6.5 Ask for DFM feedback
Top CNC manufacturers can reduce your cost by suggesting small design changes—like adding a radius, adjusting a depth, or changing a thread type. A quote that includes DFM feedback is often worth more than the cheapest unit price.
7. RFQ Checklist Before You Send
Use this checklist to ensure your RFQ is quote-ready.
- [ ] 2D drawings included (PDF, dimensioned, revision controlled)
- [ ] 3D model included (STEP/IGES)
- [ ] Material grade + condition specified
- [ ] Quantity stated (now + future estimate if possible)
- [ ] Tolerances defined (general + critical)
- [ ] Surface finish requirement stated (Ra/coating/anodize)
- [ ] Inspection requirements specified (COA/report/FAI)
- [ ] Delivery terms and location stated (Incoterms)
- [ ] Target lead time and deadline included
- [ ] Packaging requirements included if surface-sensitive
If every box is checked, you will receive faster responses, clearer quotes, and fewer follow-up questions.
8. FAQ
What files should I send for a CNC machining RFQ?
Send a 2D PDF drawing with dimensions and tolerances, plus a 3D STEP file for CAM programming. If you can only send one, prioritize the dimensioned PDF, but including both typically speeds quoting.
How do I write tolerances if I don’t need everything tight?
Use a general tolerance standard (such as ISO 2768) and then clearly mark only critical features. This helps suppliers quote accurately without adding unnecessary cost.
Should I include annual volume in the RFQ?
Yes, if you have a realistic estimate. Even a range helps suppliers offer better pricing and plan capacity. If you are unsure, state “prototype now, production potential expected” with a rough figure.
Why do different suppliers quote very different prices?
Pricing differences often come from assumptions (missing specs), machine capability, inspection scope, and internal process efficiency. A clear RFQ reduces assumptions and makes quotes more comparable.
What should I ask suppliers besides price?
Ask for lead time, inspection plan, material certificates, and DFM feedback. The cheapest price is not always the lowest total cost if it increases risk, scrap, or delays.
Ready to Get a Fast, Accurate CNC Quote?
If you want suppliers to quote quickly and accurately, send your RFQ with:
- PDF drawing + STEP model
- Material grade
- Quantity plan
- Tolerances + critical features
- Surface finish + inspection requirements
- Delivery terms + deadline
Tip: If you paste the template above into your email and attach your files, you’ll already be ahead of most RFQs suppliers receive.
