CNC Supplier Qualification Checklist
Before you send a shop your drawing, run it past this list. It covers the five things that decide whether a CNC supplier delivers the part you drew — capability, quality, quoting, IP and lead time — plus the red flags that show up later as scrap. Download the PDF, or copy it into your own sourcing file.
Qualify a CNC Shop
Five sections and 30+ questions to ask any machining supplier before you order — so the part arrives in tolerance, not in dispute.
Download checklistOr use the checklist on this page and tick items as you go.
Why a Checklist, Not a Gut Feeling
A machining drawing is a contract written in geometry. The shop that quotes the lowest number is not always the shop that delivers the part — the gap between a cheap quote and a usable part is usually a tolerance, an inspection step, or an IP control nobody discussed. This checklist turns that conversation into questions you can ask before you commit, so the surprises happen on paper instead of in a box of scrap. It is written for buyers, not engineers: you do not need to read a GD&T symbol to use it, only to know which answers should make you pause.
Five Sections, One Pass
Tick each item against the supplier you are vetting. Any section with more than two blanks is a conversation you have not finished.
1 · Capability
- Can they hold the tightest tolerance on my drawing on the process they quoted (milling, turning, 5-axis, mill-turn)?
- Do they stock or routinely machine my material (aluminium grade, stainless grade, brass, titanium, plastic)?
- What is the largest and smallest part envelope they handle, and does mine fit comfortably?
- Can they do the secondary work my part needs — threading, drilling, surface finish, assembly?
- What is their real minimum order — one piece for a prototype, or a batch minimum I cannot meet?
2 · Quality System
- Is there a documented quality process (ISO 9001-aligned or certified), not just a claim on the website?
- Can they show inspection evidence — CMM reports, first-article, certs to EN 10204 3.1 for material?
- What is 100% inspected versus sampled, and on which dimensions?
- For regulated work, do they hold the certificate my program requires (IATF 16949, AS9100, ISO 13485)?
- How are non-conformances recorded and fed back — a system, or a phone call after the fact?
3 · Quoting & Communication
- Does the quote break out material, machine time, setup, finishing and inspection separately?
- Are the assumptions stated — quantity, tolerance, surface finish, delivery terms?
- How fast is the first response, and is it from an engineer or a bot?
- Will they return DFM feedback, or just a price on exactly what was drawn?
- If the drawing is incomplete, do they flag it or quote around it and add risk later?
4 · IP Protection
- Will they sign a mutual NDA before receiving the drawing?
- How are my files stored and who can access them — and are they deleted on request?
- Do they subcontract any work, and if so, is my IP covered downstream?
- Have they published my part, photo or print without permission before?
5 · Logistics & Lead Time
- What is the realistic lead time for my quantity — prototype vs production stated separately?
- What Incoterms and freight do they quote (EXW, DAP, DDP) and who owns customs?
- What is the rework or reject handling if parts miss tolerance at incoming inspection?
- Is there a reference customer or part in my industry they can point to?
Red Flags
- No NDA or reluctance to sign one.
- Vague answers on inspection, traceability or materials.
- A single lump-sum quote with no breakdown and no stated assumptions.
- A price far below the others with no explanation of how.
- Pressure to skip the drawing review or rush the order.
- No reference parts, customers or photos they can show.
One red flag is worth a question. Three or more together is a reason to keep looking. This list is a sourcing aid, not a procurement standard — adapt it to your program.
Qualifying a CNC Supplier — Questions
What should I check before sending a CNC supplier a drawing?
Do I need a certified (ISO 9001 / IATF / AS9100) supplier?
How do I tell if a CNC quote is trustworthy?
What are the red flags when vetting a CNC machining shop?
Cite or Download
Used this in a sourcing decision or an internal standard? A link back helps other engineers find the same reference.
<a href="https://www.ataimeisen.com/supplier-qualification-checklist.html">CNC Supplier Qualification Checklist — FSCPRECISION</a>
No permission needed. Please do not rehost the page — link to it instead so the checklist stays current. The PDF is free to download and share internally.
Want a supplier that passes the list?
Send the drawing and we'll quote it with material, time and finish separated, sign an NDA first, and return DFM feedback and inspection to the tolerance you specify. Ask us any question on this checklist — we'll answer it straight.