The RFQ Data Package: What to Send a Chinese Machine Shop
Short answer: an RFQ data package is the complete set of files and statements a shop needs to quote accurately — and the single most common reason quotes are wrong or slow is an incomplete package. The full package: a STEP file plus a PDF drawing with title block; material grade written out with finish; a tolerance strategy that marks critical features only; quantity, target date and destination; and commercial basics (Incoterms, inspection documents wanted). Sending this complete package gets you a usable quote in one round instead of three emails of back-and-forth.
A machine shop quotes what it can see. Every missing piece of the RFQ package forces the shop to guess, and guesses come back as padded prices, wrong process choices, or questions that cost you a day each. This guide is the checklist for a package that produces accurate, comparable quotes from any Chinese shop.
The Drawing and Model: Files That Matter
Send two files minimum: the native or neutral 3D model (STEP is the universal choice; IGES where the shop asks) and a PDF drawing with a proper title block. The STEP lets the shop program and check machinability; the PDF is the contractual dimension source. Name both files with part number and revision (e.g., "BQ-1042-REV-C.step") so version confusion is impossible. Never send only a screenshot, only a 2D print, or only a model without a drawing — each gap invites a different wrong guess about your intent. If the part is a revision of something they made before, say so and highlight what changed.
Material and Finish: Write Out the Full Callout
Write the material so a buyer cannot misread it: "6061-T6 aluminum, ASTM B221" beats "aluminum"; "AISI 304 stainless" beats "stainless"; "C5210 phosphor bronze, half-hard" beats "bronze." Add the finish as its own line: "clear anodize, Class II" or "zinc plating, clear trivalent" or "as-machined, 32 Ra." Material and finish drive a big share of the price difference between quotes, and vague callouts produce wildly different quotes for the same "part." If the application allows substitution, say which grades are acceptable — otherwise the shop quotes its most expensive safe assumption.
Tolerance Strategy: Mark the Few, Not the Many
| What you write | What the shop does |
|---|---|
| All dimensions ±0.05 mm | Standard machining; honest quote |
| Critical features ±0.01 mm (marked) | Precision work where needed; price reflects it |
| Every dimension ±0.01 mm | Quotes as if all are critical — expensive and slow |
| GD&T on functional features | Correct interpretation of form/location intent |
| No tolerance note at all | Assumes standard, but flags missing spec |
The tolerance strategy is where over-specification costs the most: marking every dimension tight forces the shop to plan every feature as a precision operation. Mark the functional few — mating diameters, locating surfaces, threaded features with class — and leave the rest at standard. Add GD&T symbols for position and flatness where function demands; a proper drawing with three critical callouts quotes faster and cheaper than a "all tight" drawing.
Commercials: Quantity, Date, Destination
State the quantity as a number and a scale: "500 pcs initially, potential 5,000/yr" tells the shop whether to quote for batch or production flow. State the target delivery date and whether samples are needed first ("samples by [date], production by [date]"). State the destination country and your preferred Incoterms (EXW, FOB, DDP), because freight and import handling change the quote structure. And list the inspection documents you expect with the order — FAI report, material certificate, inspection certificate — so the shop prices the QC work instead of discovering it later.
The Questions List: Finish With a Numbered Few
Close the RFQ with a short numbered list of questions whose answers shape your decision: What is the MOQ and how does price step with quantity? What are sample and production lead times? What tooling or setup costs apply, and who owns any tooling after full payment? Which inspection documents are standard? Do you provide DFM feedback on the drawing? Numbered questions produce numbered answers, which translate cleanly and compare easily across suppliers. A shop that answers with more questions about your application is engineering the job — the sign of a quote worth reading.
Frequently Asked Questions
Q: What files should I send in an RFQ to a Chinese machine shop?
A: A STEP file (3D model for programming and machinability review) plus a PDF drawing with title block (the dimensional contract). Name both with part number and revision. Add material, finish, tolerance strategy, quantity, dates and commercial terms — the complete package gets an accurate quote in one round.
Q: How do I write material specs in an RFQ?
A: Write the full grade and standard: "6061-T6 aluminum," "AISI 304 stainless," "C5210 phosphor bronze half-hard." State finish as its own line (anodize class, plating type, surface finish). Vague callouts produce wildly different quotes for the same part.
Q: How many tolerances should I specify?
A: Mark the functional few: mating diameters, locating surfaces, threaded features with class, and critical GD&T callouts. Leave the rest at standard (±0.05 mm typical). Over-tolerancing every dimension forces the shop to quote everything as precision work — slower and costlier for no functional gain.
Q: Should I include commercial terms in an RFQ?
A: Yes: quantity and annual scale, target dates for samples and production, destination country and preferred Incoterms, and the inspection documents you expect. These shape the quote structure and let shops compare apples to apples — omitting them produces quotes you cannot compare.
Q: What questions should I ask in an RFQ?
A: A numbered shortlist: MOQ and price stepping with quantity, sample and production lead times, tooling/setup costs and tooling ownership, standard inspection documents, and whether they provide DFM feedback. Numbered questions produce clear, comparable answers.
Authored by the BQUQ Engineering Team. BQUQ is an ISO9001-certified source factory in Dongguan, China, running CNC machining, metal stamping, custom springs, heat sink and collet lines under one roof. Send drawings to sc@bquq.com or WhatsApp +86 13713157787 for a quote within 12 working hours. www.bquq.com
