When three quotes come back on the same drawing and the spread is three to one, the usual conclusion is that one shop is expensive and another is cheap. Far more often, the three shops quoted three different parts — because the RFQ left enough undefined that each filled the gaps with its own assumptions.
The takeaway up front: a quote is only as specific as the request behind it. Every requirement you leave out becomes an assumption the supplier makes, and suppliers assume in the direction that wins work — the loosest tolerance interpretation, the cheapest finish, the minimum inspection. You discover the difference at first article, or at the receiving dock.
A complete RFQ costs an hour more to write and removes most of that risk. Here is what belongs in one.
Why incomplete RFQs produce unusable quotes
Three specific things happen when the package is thin.
Suppliers price different scopes. One includes fixturing in the piece price, another quotes it as separate non-recurring cost, a third assumes you already have it. No amount of side-by-side analysis makes those numbers comparable.
Risk gets priced as padding. A shop that cannot tell how tight a tolerance really is, or whether you will demand full dimensional reports, adds margin to cover the worst case. Ambiguity is not free, and you pay for it on every unit.
The good suppliers decline. Capable shops with full order books triage RFQs. A vague package with no drawing revision, no volume, and no timeline reads as price-fishing and goes to the bottom of the pile. You end up choosing from whoever was hungry rather than from whoever fits.
The ten sections a manufacturing RFQ needs
1. The part definition
A dimensioned drawing plus a 3D model, both with a revision number and a date. State which one governs if they disagree — normally the drawing. Sending a model alone is common and it is a mistake: the model carries geometry but not tolerances, finish callouts, or inspection requirements, so the supplier guesses at exactly the things that drive cost.
2. Tolerances and critical dimensions
Do not tolerance everything tightly to be safe. That is the single most expensive habit in custom manufacturing, because tight tolerances drive process choice, fixturing, cycle time, and inspection load all at once. Apply a sensible general tolerance block, then identify the handful of dimensions that genuinely matter for fit or function and call those out as critical. If you use geometric dimensioning and tolerancing, name the standard — ASME Y14.5 or the ISO GPS series — and check that your datums are usable for fixturing.
3. Material specification
Name the grade and standard, not the family. "Aluminium" is not a specification; 6061-T6 is. Include any condition or temper, and say whether substitutions are acceptable — permitting an equivalent grade can improve price and lead time, but that has to be your decision, not the supplier's.
State whether you require material certification and to what level. Certificates traceable to the heat lot are routine in regulated work and add cost, so ask for them where they matter.
4. Finishing and secondary operations
Surface finish, plating, anodising, painting, heat treatment, deburring, marking, and any assembly steps, with the specification and class or thickness where one applies. Cosmetic requirements matter too — "no visible tool marks on the A-face" is a real cost driver and belongs in writing rather than discovered at inspection.
5. Quantities and the schedule behind them
Give a prototype quantity, an initial production quantity, and a realistic annual estimate, and ask for pricing at several break points — a shop's cost structure changes with batch size and you want to see where the steps are.
Say whether the volume is a one-off, a blanket order with releases, or an ongoing forecast. A supplier who knows there is repeat business behind a part will invest in fixturing and price accordingly. One who assumes a single batch will not.
6. Quality requirements
This section separates a professional RFQ from a hopeful one. Specify:
- Which quality management standard the supplier must hold — ISO 9001 as a baseline, with sector standards such as IATF 16949, AS9100, or ISO 13485 where they apply.
- What first-article documentation you expect, and in what format.
- Whether you require a production part approval package, a certificate of conformance, or a dimensional report on every shipment.
- The inspection plan: which characteristics are checked, at what frequency, and whether sampling or 100% inspection applies.
- What happens with non-conforming material — containment, notification time, and disposition authority.
These requirements carry a real price, which is precisely why they belong in the RFQ — asking afterwards is a change order. The logic of building quality in rather than inspecting it in is covered in the quality control guide.
7. Packaging, labelling, and delivery
How parts arrive matters more than people expect: bulk versus individually protected, ESD requirements, labelling and barcode format, pallet configuration. Parts damaged in transit are a recurring and avoidable cost.
8. Commercial terms
State the Incoterms rule and the named place — the difference between EXW and DDP can be a large share of the landed cost, and quotes on different terms are not comparable. Include payment terms, currency, and required quote validity period.
Ask explicitly for tooling and fixturing as separate line items, and ask who owns the tooling. Unclear tooling ownership is one of the most common ways a buyer discovers they cannot move a part to a second source.
9. Timeline
Give three dates: when quotes are due, when you intend to place the order, and when you need first parts. Ask for prototype and production lead times separately, plus the shop's current capacity position. A supplier who is honest about being eight weeks out is more useful than one who agrees to your date and misses it.
10. What you need back, in a fixed format
Tell suppliers exactly how to respond: piece price at each quantity break, tooling and non-recurring costs itemised, lead time, minimum order quantity, quoted material grade, process route, and any exceptions to your specification. That last item is the most valuable line in any quote — an exception stated up front is a negotiation; one discovered later is a dispute.
Sending it: a few practices that improve the responses
Send the same package to every supplier at the same time, and circulate clarifying questions and answers to everyone who received it. Staggering the send, or answering one shop privately, means you are no longer comparing like with like.
Send it to a shortlist of three to five suppliers you have already screened for capability, not to twenty. Volume of quotes is not the goal; comparability is. Screening criteria are covered in the guide on vetting a contract manufacturer.
Finally, treat a supplier who asks good questions as a positive signal. A shop that queries your datum scheme or asks whether a tolerance is functional is doing engineering on your part before they have the order. A shop that quotes a complex drawing in an hour without a single question has usually not read it.
Reading the quotes that come back
Normalise before you compare: put every quote on the same Incoterms basis, add tooling amortised across the first order, and include inbound freight and duty.
A quote far below the others is not automatically good news. Check the material grade quoted, the process route assumed, whether the inspection requirements are reflected, and whether exceptions are listed. The usual explanation for an outlier is that the supplier quoted a simpler part than the one you asked for — the same dynamic that makes nominally identical components perform differently, discussed in the piece on OEM and aftermarket part quality.
FAQ
How many suppliers should I send an RFQ to?
Three to five, all pre-screened for the capability and volume you need. Fewer than three gives you no market reference; many more produces a pile of quotes you cannot properly normalise, and signals to good shops that you are price-fishing. The shortlist's quality matters far more than its length.
Should I include a target price in the RFQ?
A target price helps a supplier tell you quickly whether the part is feasible at your budget, and can prompt useful suggestions about design or process changes that would get you there. The risk is anchoring — quotes cluster just under your number rather than reflecting real cost. A reasonable compromise is to state a target only when you genuinely want design-for-manufacture feedback.
What is the difference between an RFI, an RFQ, and an RFP?
A request for information gathers capability data to build a shortlist. A request for quote asks for a price against a defined specification. A request for proposal asks suppliers to propose an approach as well as a price, and suits projects where the solution is not yet fixed. Sending an RFQ while the design is still moving is a common cause of quotes that expire before you can act.
How long should I give suppliers to respond?
For a simple machined or fabricated part, one to two weeks. For an assembly with sub-tier sourcing, allow three or more, because the supplier has to collect quotes of their own. Compressing the window mainly buys padded numbers, since a shop that cannot cost the job properly prices the uncertainty instead.
Do I need drawings if I have a 3D model?
Yes, for anything with functional requirements. The model defines nominal geometry; the drawing defines tolerances, datums, material, finish, marking, and inspection requirements — the things that determine cost and acceptance. Model-based definition can replace a drawing, but only when the model carries that annotated data and both parties can consume the format.
Send one spec, not five interpretations
A good RFQ is not bureaucracy. It is the cheapest quality tool you have, because it forces the decisions that would otherwise be made for you by whichever supplier guessed most optimistically. Work through the ten sections, send an identical package to a screened shortlist, and normalise the responses before comparing them. When you are ready to build that shortlist, use Manufax to find verified contract manufacturers by capability, material, and region and send one spec to suppliers that actually fit.
