What to include in a China CNC RFQ so quotes match the part

This how-to is for a US or EU buyer or engineer sending work to a China factory. You can have a perfect model and still get a quote that is wrong because quantity, Incoterms, or inspection were missing.

A Dongguan shop prices what it can see. If a field is blank, the estimator fills it with the cheapest assumption. Custom CNC machining services get more accurate when you close those blanks before the first reply.

Key takeaways

• Files (STEP + PDF + revision) are mandatory. They are not the whole RFQ.
• Quantity breaks, inspection scope, and Incoterms 2020 move the number as much as cycle time.
• Alloy + temper + finish + before/after coat must be on the RFQ, not in a later chat.
• Write the inspection you will use to reject parts. If you do not, the quote will not include that CMM time.
• One timestamped package beats a drip of screenshots. Freeze the revision, then change it with a new letter.

What to include in a China CNC RFQ: files and revision

What to include in a China CNC RFQ starts with a revision-controlled pair: STEP (AP214 or AP242) and a PDF drawing.

The PDF owns datums, tolerances, threads, and notes under ASME Y14.5-2018. The STEP owns volumes and tool access. Put the same revision letter in both filenames and in the email subject. If purchasing forwards Rev B while engineering already cut Rev C, the quote is fiction. Name files like P-33011_REV_C.step and P-33011_REV_C.pdf. A download named final_v3_USE_THIS.stp is how mixed revisions start.

Name a general class for unmarked sizes, usually ISO 2768-m per ISO 2768-1 (1989). Medium class on 6-30 mm is ±0.2 mm. Then number the fits. “Machine to print” with a blank title block is not a specification. Native CAD can be extras. STL is not a machining file.

If the part is a family (left/right, long/short), send one zip per part number or a table that maps file to dash number. Do not expect the estimator to unpack a multi-body STEP and invent which body is which PO line. If you want CNC milling and CNC turning on the same assembly, say which bodies are mill, which are turn, and which are bought hardware.

Read About YXT CNC before you add a documentation clause the shop cannot support. Asking for a process the factory does not run is how RFQs stall. Asking for a mill cert, a ballooned FAI, and a named Incoterm is normal and should be on the first page.

What to include in a China CNC RFQ: process, finish, and inspection

What to include in a China CNC RFQ for process is every operation that is not mill or turn and ship raw.

Call material as 6061-T6, 7075-T6, 304, 316, 4140, POM, with temper. Call finish: as-machined Ra 3.2, bead blast, Type II anodize, Type III, zinc, passivate. If sizes apply before coat, say so. If they apply after, give a thickness range. Type II per MIL-A-8625F (1993) is commonly 5-25 µm. That range can consume a tight bore if you measure after dye.

Call inspection: ballooned FAI, CMM on listed features, or incoming sampling. If you will reject on a CMM true-position report, the quote must include that time. Secondary ops belong here: heat treat, grind, insert install, laser mark, packing for cosmetic faces. Hiding them until after PO is how quotes go stale. A helical insert in 8 holes is a tap plus install plus a gauge. It is not “included in mill time.”

If you need a mill cert or EN 10204 3.1, write it on the RFQ. Special processes should name the spec you will audit, or name the result: “Type II black, 8-12 µm, no dye on datum A.” Do not write “aircraft quality” or “medical grade” as a substitute for a finish and an inspection list.

For prototype quantities, still list the same fields. Small-batch CNC machining uses the same RFQ skeleton. Five pieces still need a temper, a finish rule, and a FAI plan. The shop may skip a production fixture. It should not skip the drawing notes.

Ra 0.8 µm on all faces, 100% CMM, and Type III on a cosmetic cover are three cost knobs. Turn each one on only if you will use it to accept or reject. A seal face at Ra 0.8 is a reason. A hidden pocket floor at Ra 0.8 is extra passes.

Quantity breaks, lead time, and Incoterms 2020

Quantity is not one number. Send the breaks you might order: 5 / 20 / 100, or 50 / 200. Setup and programming sit on the first pieces. A quote at qty 1 cannot be divided to get qty 200. Programming, fixturing, and CAM prove-out do not shrink by 200. Chip time does. If you only send qty 5, then order 80, you are buying a new structure, not a discount off the prototype line.

Lead time is a window after drawing freeze, not after the first email. Write “need parts 15 business days after Rev C approval.” If you need a partial ship of 5 pieces, say that. “ASAP” is not a date. A shop cannot protect spindle time against a revision that is still moving.

Freight terms change the invoice more than buyers expect. Incoterms 2020 define who pays and where risk transfers. FOB or FCA Shenzhen is a factory-plus-export number. DAP or DDP to your dock includes onward freight, and DDP can include import duties depending on how the clause is used. If you leave Incoterms blank, you will compare one shop’s door price to another shop’s landed price. That comparison is how the “cheap” quote loses after brokerage.

State ship-to country. Add “export carton, rust prevent, labels with PO and rev” if the parts are finished metal. Cosmetic anodized faces need bagging or film. Heavy steel needs rust prevent. These notes are packing, not decoration. Missing packing on a dyed housing is how a good mill lot fails incoming cosmetics.

If you will use your forwarder, FCA plus the forwarder’s name is cleaner than mixing DDP language into a factory-door bid. If you want one number to your dock, say DAP or DDP and the postal city. Do not mix both in the same RFQ.

Send the RFQ so the quote basis is frozen

Use a single send, not a drip of chat screenshots.

1. Zip STEP + PDF with matching revision letters. Done when filenames and the title block show the same rev, and only that rev is in the zip.
2. Write an RFQ header: part number, alloy/temper, finish, quantity breaks, inspection, Incoterms 2020, ship-to country. Done when a stranger can quote without opening your email thread.
3. List open questions in one bullet list (missing radius, optional grind, alternate 6061 vs 7075). Done when the shop can answer yes/no instead of redesigning the part.
4. Send one email or one form upload with the zip and the header. Done when there is a single timestamped package to reference on the quote.
5. Freeze that package. If you change a hole, bump the revision and resend the header. Done when the quote number points at Rev C, not at a verbal change.

The usual failure is a STEP on Monday, a finish note on Wednesday, and a DDP request after the quote. Each drip is a new job. If you want a DFM pass, use YXT CNC contact and ask which fields are still blank. Ask for missing radii and coating-vs-size conflicts, not for a new design.

Keep the commercial header in the body, not only inside the PDF. Purchasing forwards PDFs. Estimators search email. If Incoterms live only on sheet 2 note 14, someone will quote EXW by habit.

Worked RFQ: header plus files for a 304 bracket

Here is a complete first send. Part P-33011, 304 stainless bracket, 80 × 45 × 12 mm, 2× Ø6.00 ±0.02 locating holes, 4× M5×0.8-6H.

Zip:

• P-33011_REV_B.step
• P-33011_REV_B.pdf (ISO 2768-m, datums A-B-C, Ra 3.2 unless noted)
• one-line file list with Rev B and the date

Header you can paste:

“`

RFQ: P-33011 Rev B

Material: 304 stainless, 2B or mill stock as available, mill cert EN 10204 3.1 required

Finish: as-machined, passivate, no bead blast on datum A

Qty breaks: 5 / 25 / 100

Inspection: ballooned FAI; CMM on A-B-C and 2× Ø6; later lots sample those two holes

Incoterms 2020: FCA Shenzhen

Ship-to: Netherlands (buyer forwarder after FCA)

Packing: export carton, rust prevent, PO and rev on label

Open questions: may we open internal pocket radii from R0.5 to R1.5? 6061-T6 is not allowed.

“`

That header plus the zip is what to include in a China CNC RFQ if you want the quote to survive purchasing. The weak version is “304 bracket, 20 pcs, send price” with a STEP and no Incoterms. The weak version will still get a number. The number will not include the 3.1 cert, the CMM, or the freight basis you thought you were comparing.

RFQ field	If omitted, shop assumes	Effect on accuracy	Put it where
STEP + PDF + rev	Shape only, or mixed revs	Wrong toolpath or wrong hole	Zip + subject line
Alloy + temper	Cheapest common stock	Strength and distortion wrong	Title block + header
Finish + coat vs size	As-machined	Masking and fits missing	Drawing notes
Qty breaks	The one number you typed	Setup cost mis-spread	Header
Inspection	Caliper / visual	CMM time missing	Drawing + header
Incoterms 2020	Factory door	Landed cost not comparable	Header
Certificates	None	Incoming QA block later	Header
Packing / labels	Shop standard carton	Cosmetic or rust claims	Header
Open DFM questions	No changes allowed	Either extra cost or silence	Header bullets

Bottom line: the RFQ fields that change quote accuracy are revision, alloy/temper, finish, quantity breaks, inspection, and Incoterms 2020. Close them on the first send.

A second checklist you can print next to the send button:

1. One rev letter in STEP, PDF, subject, and header.
2. Grade and temper, not “stainless” or “aluminum.”
3. Finish type, and before/after size if coated.
4. Qty at least two breaks, even if you only need the first.
5. FAI list, not “good quality.”
6. Incoterms 2020 plus city or port.
7. Ship-to country and who books freight after FCA/FOB.
8. Certs named or explicitly “none.”
9. Packing for cosmetics or rust.
10. Open questions as yes/no, not a redesign essay.

If item 1 or 2 is missing, do not send. Everything else is how the number moves after you think you have a quote.

Ask the shop to echo the same fields on the quote PDF: Rev B, 304, passivate, qty 5 / 25 / 100, FAI plus CMM on the two Ø6 holes, FCA Shenzhen, EN 10204 3.1. If the quote says “stainless bracket, EXW, visual inspect,” it is not a reply to this RFQ. Treat it as a new assumption set and send the header again. A usable quote also states validity against that revision letter, so a later hole change cannot hide inside an old number.

For a prismatic 304 bracket like P-33011, do not add a 5-axis requirement. Two 3-axis setups cover the faces. Save rotary-axis language for compound ports. That process note belongs in the header next to inspection, because it changes which mills bid and how fixtures are counted. Lead time should still be written as business days after Rev B freeze, not after the first chat.

FAQ

What is the minimum to include in a China CNC RFQ?

STEP, PDF, matching revision, alloy and temper, finish, quantity, inspection scope, and Incoterms 2020 with a ship-to country. That set is the minimum that lets an estimator price tools, coating, CMM time, and freight basis. Photos, native CAD, and a sample are extras. “Aluminum, 10 pcs, need price Friday” is not a minimum. It is an invitation to assume 6061-T6, as-machined, factory door, and caliper inspection. Those assumptions are why the second quote, after DFM, does not match the first.

Do I need to specify Incoterms on a prototype RFQ?

Yes if you will compare shops or need a landed cost. A factory-door price is not DAP to your dock under Incoterms 2020. Five prototype pieces still ride a carton, a waybill, and a risk-transfer point. FCA or FOB keeps freight in your forwarder’s hands. DAP or DDP asks the shop to include onward carriage. Mixing one shop’s EXW with another shop’s DAP makes the “cheaper” mill look expensive or the reverse. Put the same Incoterm on every bid you intend to compare, including qty 5.

Should I send quantity breaks or only the first order qty?

Send breaks (for example 5 / 20 / 100) even if you only need 5 now. Setup does not scale. Programming, fixtures, and FAI sit on the front of the curve. Chip time sits on the rest. If you later order 80 against a qty-5 quote, you are not entitled to a linear discount, and the shop is not playing games. Three breaks let you see where setup stops dominating. If you truly will never buy more than 5, say so, and do not ask for a 200-piece number you will not use.

How do I ask for CMM inspection without overpaying?

List the features on the report (datums and fits). Do not ask for 100% CMM on ISO 2768-m faces unless you will reject on those faces. A ballooned FAI plus CMM on A-B-C and two locating bores is a bounded hour. “CMM all dimensions 100%” on a 40-balloon drawing is a different job. If production lots only need a sample of the fits, write the sample. Incoming QA at your dock should match that list. Surprise true-position reports after PO are how quotes go stale.

Can I leave material as “aluminum” and let the factory choose?

No. 6061-T6 and 7075-T6 do not meet the same drawing. Put the grade and temper on the RFQ. Yield, corrosion, anodize color, and distortion are different. A shop that picks 6061 to win a bid is not cheating if you wrote “aluminum.” You asked them to choose. If 7075 is required by stress, write 7075-T6 and do not accept a silent swap. If 6061 is acceptable as a cost-down, write that as an alternate line, not as a blank.

What file formats do China CNC factories want?

STEP plus PDF is the default. IGES or X_T can ride along. STL is not enough. Native CAD helps only when the receiver has that seat. Export AP214 or AP242 from the released configuration. Match the revision letter across files. If you have an assembly, send the machined bodies, not a STEP full of fasteners the shop should not cut. A drawing package with a commercial header is still required. Pretty renders in the email do not replace balloons.

Should prototypes skip mill certificates and packing notes?

Only if you will not inspect certs or cosmetics on that lot. Qty 5 still rusts, still dyes, and still gets stopped at incoming if your QA requires EN 10204 3.1. If the prototype is a shop fixture that never ships, “no cert, as-machined, FCA” is a clean skip. If the prototype is the first article of a production design, use the production RFQ skeleton and shrink quantity, not the field list. Skipping packing on dyed aluminum is how the first photos from the dock look worse than the mill photos.

Is a WeChat voice note a valid RFQ change?

No. Bump the revision and resend the header. Voice notes, screenshot crops, and “make the hole 8.2” in a chat are how Rev B quotes get built to Rev C geometry. Put the change on the drawing, change the letter, zip again, and point the quote number at the new rev. That is slower by a day and cheaper than a lot that does not match the file you thought you ordered.