What to Include in a CNC Machining RFQ
For buyers and engineers sending drawings out for quotation.
A complete request lets suppliers price the same part under the same conditions, while unrelated material slows the review down. This guide lists what to include, what to leave out and how to compare the answers you receive.
What a Machining Quote Has to Price
A machining quote is built from material, set-ups and machine time, secondary operations such as finishing or heat treatment, inspection and documentation, packaging and delivery. Each of these depends on information in your request. If one is missing, the supplier either asks, which takes time, or assumes, which leaves quotes from different suppliers describing different scopes.
The aim is a request that fixes every cost driver once, in writing, for each part number. That does not mean sending everything you have. A full product data pack, unrelated assembly files or internal test results add review time without changing the price, and they spread design information further than necessary.
Related: Small-batch production
The Core Package for Each Part
For every part number, the items below cover the decisions that change price and acceptance. Put them on the drawing where possible, since an email can be lost between quotation and order, and keep one file set per revision so nobody quotes from an outdated copy of the part.
a 2D drawing and a 3D model at the same revision, with a statement of which governs if they disagree.
the quantity for this release and likely repeat quantities as separate price breaks.
grade, temper or condition, and whether equivalents are acceptable.
specification, class, thickness range and masked areas.
critical features, inspection reports and certificates required with delivery.
required date, destination, packaging and marking.
How Each RFQ Item Changes the Price
Buyers sometimes leave items out because they seem obvious, or because they are still being decided. The table shows why each item changes the quote and how to state it so that every supplier prices the same scope, including the parts of the request that are still open.
| RFQ item | Why it changes the price | How to state it |
|---|---|---|
| Drawing revision | A different revision may be a different part | Revision on every file name and in the request text |
| Quantity | Programming and set-up are spread across the quantity | A separate price for each quantity you may order |
| Material and condition | Stock cost, availability and machinability vary | Exact designation and temper, plus acceptable alternatives |
| Finish | Adds a process, masking and possibly two-stage inspection | Specification, class, thickness range and coverage |
| Critical features | Tight features may need extra operations or special gauging | Marked on the drawing or listed by balloon number |
| Inspection and certificates | Reports and certificates take inspection and administration time | Report type, coverage and certificate type, such as EN 10204 type 3.1 |
| Packaging and delivery | Protection, labelling and documents add labour | Packing requirements, labels and destination |
Related: Small-batch production
Quantity breaks
ask for the quantity you will order now and one or two likely follow-on quantities. More breaks add work for the supplier without improving the decision.
Assemble the Request in a Fixed Order
Working through the request in the same order each time avoids the usual gaps.
Revision, critical features, quantities, material and finish, records, open questions — concept illustration
Freeze the revision first, because everything else refers to it. Then mark the features that decide fit and function, add quantities, material and finish, and define the records you need at receipt. Finish with the open questions and any confidentiality or export-control requirements, so they are handled before the files circulate.
Related: Contact the team
- 01Freeze
confirm the drawing and model revision and the file names.
- 02Mark
highlight critical features and datum faces.
- 03Quantify
list the quantities to be priced and expected repeats.
- 04Specify
material, condition and finish.
- 05Accept
reports, certificates and any sampling plan.
- 06Flag
open questions, acceptable alternatives and confidentiality requirements.
What to Leave Out or Send Later
A focused request is easier to review. Send the drawings of the parts being quoted, plus mating parts only where an interface needs to be understood. Leave out superseded revisions, marketing specifications, internal test data and system-level documentation that does not change how the part is made or accepted. Where a feature's purpose matters, a one-line explanation usually helps more than a full assembly file.
Confidentiality is a separate decision. If a non-disclosure agreement, a restricted file channel or export-control screening is required, raise it before sending the drawings rather than after. Removing sensitive title-block information, or sending only the parts in scope, reduces exposure without weakening the request, because the supplier still sees every feature it has to price.
Related: Drawing confidentiality and file handling · Contact the team
Requests for more data
when a supplier asks for extra information, ask which cost or acceptance question it answers. That keeps the exchange focused on the part.
Flag Open Questions Instead of Hiding Them
Many requests go out before the design is final. That is workable when the request says what is still open: a tolerance under review, a sharp corner that might accept a radius, a thin wall that could be thickened, a finish not yet chosen. A supplier can then quote the current drawing and comment on the alternatives, instead of guessing which version you will order.
Specialised parts benefit most. On RF housings, waveguides and cavity parts, a short note on which surfaces affect electrical performance, and whether RF testing stays with your team, helps the supplier focus its manufacturing review on the features that carry the risk and price them accordingly.
Related: RF and microwave machining · Reviewing thin-wall parts · Defining waveguide drawing requirements
Compare the Quotes You Receive
A quote is comparable only when it answers the same request. Before ranking prices, read each quote against your package and note where it differs. Differences are not necessarily problems; they are decisions you need to make before ordering and then record in the purchase order.
Revision and part number: quoted against the files you actually sent.
Quantities: the same price breaks, with set-up or tooling charges shown separately if they apply.
Inclusions: finishing, inspection reports, certificates and packaging, each included or excluded.
Deviations and assumptions: changes to tolerances, material, finish or process the supplier needs.
Validity: how long the price holds and what triggers a new quote, such as a revision change.
Related Pages
Continue with the closest related part family or guide.
Reviewing Thin-Wall Parts Before a Quote
What makes a wall thin for machining, what to send for review, which design options to discuss and how thin features should be measured.
From an Approved Prototype to a Controlled Batch
What a sample approval covers, and what still has to be frozen, inspected and agreed before the first controlled batch is released.
What to Clarify When a Drawing Revision Changes
What to send with a revised drawing, and which quote, manufacturing, inspection and order details need re-confirming afterward.
Questions About Preparing an RFQ
Is a STEP model enough without a 2D drawing?
A model defines geometry, but usually not tolerances, finish, material condition or inspection requirements. Some suppliers can quote from a model plus a separate requirements sheet, yet a drawing remains the clearest place for those requirements. If you send both, state which one governs where they differ, and keep them at the same revision.
Should we send the whole assembly?
Usually not. Send the parts being quoted and the mating parts for any interface whose function is not obvious from the drawing. A short note on what each critical feature does is often enough for the manufacturing review. Sending less also limits how widely your design data circulates outside your organisation.
Which drawing conventions should the request state?
State the units, the projection method and the standard that governs geometric tolerances and general tolerances, for example ASME Y14.5 or the ISO GPS series with a named general tolerance class. The same symbol or default can be read differently under each system, so naming them on the drawing prevents two suppliers from quoting two interpretations.
What if some tolerances are not final yet?
Say so and mark them. Ask for a quote on the current drawing and, where useful, a comment on how a tighter or looser value would affect cost or route. The supplier then prices what exists, and you get information for the design decision instead of a price based on a guessed final version.
Can we add inspection reports or certificates after the quote?
You can, but they may change the price and the schedule, because inspection time and paperwork are part of the cost. State report types, coverage and certificate types in the request, even as a draft, so they are included from the start and different quotes cover the same documentation.
Discuss Your Next RFQ
Send the drawing and model at the same revision, the quantities you want priced, and the material and finish.
Sales contact (pending)
Name, role and photo to be confirmed
Drawings are optional for an initial discussion.
Start with the information you have; file exchange can be arranged afterward.
Name to be confirmed
Sales, company name to be confirmed
- Add the reports or certificates you need at receipt and anything still undecided.
- If the files are not ready, a short description of the part is enough to start.
Project Inquiry
Fields marked are required.