On this page
You send a drawing and ask for a price. The supplier replies with questions about material, quantity and finish. Another supplier gives you a number immediately, but the quote does not say which requirements it includes. Before you can compare the two, you are already revising the inquiry.
A useful CNC machining RFQ—request for quotation—gives each supplier the same part definition and the same purchasing scope. It does not need to be a long document. It needs to make clear what is fixed, what is still open and what you expect to receive.
This guide walks through the information to include, with a sample file package, an email you can adapt and a checklist to review before sending your drawings.
Start with one clear RFQ package
Put the current files, part list and purchasing notes together rather than asking a supplier to reconstruct the job from several emails. For one component, a model, drawing and short message may be enough. For several components, add a list that connects every part number to its revision, material and quantity.
Give the supplier a contact for technical questions as well as a contact for purchasing. These can be the same person. What matters is knowing who can resolve a drawing question and who can approve a change to the order.
| Information | What the supplier needs to know |
|---|---|
| Part files | Current model and drawing, part number, revision, units and any unresolved differences. |
| Material | Exact grade and condition, relevant specification and whether alternatives may be proposed. |
| Quantity | Sample quantity, each production batch and any forecast shown separately. |
| Finished condition | Surface treatment, functional and cosmetic areas, and the condition in which dimensions are accepted. |
| Acceptance records | Required measurements, certificates, sample approval and report format. |
| Delivery scope | Required dates, delivery destination, packaging, and costs to include or identify separately. |
Missing information is not a reason to disguise an assumption as a requirement. Write “material under review” or “finish to be agreed” when that is the actual situation, and request a provisional estimate with those assumptions stated.
Send the current model and drawing together
For a conventional model-and-drawing package, the 3D model communicates the shape and the drawing carries the specified dimensions, tolerances and notes. A plain solid model should not be assumed to contain every acceptance requirement. For example, Protolabs asks for both a model and a drawing for its GD&T-toleranced precision work; its specific requirements are not a universal rule for every supplier.[2]
Ask which file formats the supplier can use. A STEP model and readable PDF drawing are a practical starting point for the sample package below. When your workflow uses annotated model-based definition instead, agree which model, annotations and associated documents define the part. Do not assume a screenshot is a substitute for either workflow.
Make the revision impossible to miss
Use the same part number and revision in filenames, drawing title blocks and the inquiry. Remove superseded files from the package. When revising an RFQ, state which version the new files replace and ask suppliers to identify the revision used in their quotation.
Resolve conflicting dimensions before production. If the PDF and model disagree, ask the supplier to flag the discrepancy rather than choose silently. Agree the document that governs the requirement and issue a corrected package. A sentence in an email should not leave two competing definitions in circulation.
Identify the features that control assembly
A bearing seat, sealing face or locating hole deserves more attention than a non-functional outside surface. Mark the required dimensions and relationships on the drawing. GD&T provides a defined language for communicating geometric requirements on drawings and digital models; use the convention and edition required by your project.[1]
Do not request the tightest tolerance everywhere as a substitute for design intent. Unnecessarily restrictive requirements can add processing and cost, while loose requirements on mating features can prevent assembly.[2] Describe the required fit and let the responsible engineer define the limits.
Specify the grade and the delivered condition
“Aluminum” is not a complete purchasing specification. Record the alloy and temper or condition specified by the design, together with any applicable material standard. For plastics, include the exact grade, filler and color when these matter. A trade name alone may not identify the material your application requires.
Also state what must be true at delivery. If the drawing calls for heat treatment, specify the required final condition and any records you need. If material certificates or lot identification are required, request them at the quotation stage rather than after the parts have been made.
Keep alternatives separate from the base quote
It is reasonable to ask whether a different material or stock form would make the part easier to source or machine. Ask for the specified material as the base quote, with each proposed alternative clearly separated. A supplier suggestion is not approval to change the part.
When the material is not decided, share the relevant service conditions: temperature, load, contact with other parts, electrical requirements and exposure to fluids. Use that information to start a technical discussion. For related reading, browse the Materials & Design section of the Knowledge Center.
Separate sample quantities from production demand
Ask for the quantities you are actually considering. Five prototypes, a first batch of fifty and an annual forecast of one thousand are three different requests. Identify whether quantity breaks are alternative order sizes or consecutive stages of the same project.
| Stage | Quantity | How to describe it |
|---|---|---|
| Prototype evaluation | 5 | Quote separately; define the evaluation requirements. |
| First production batch | 50 | Subject to the agreed sample approval. |
| Annual forecast | 1,000 | Planning information only—not a released order. |
Ask whether programming, fixtures, special tooling or inspection preparation are included in the unit price or listed separately. Also ask which charges would recur on a later order. Avoid assuming the first quotation automatically establishes the price for every repeat batch.
If the design may change after testing, say so. Requesting a prototype quote against a development revision is different from releasing a stable design for repeat production. Both can be discussed without pretending the later order is already confirmed.
Describe the finish on the surfaces that matter
Specify the treatment rather than relying on a broad appearance word such as “polished.” Anodizing, plating, bead blasting and passivation are different processes, with different purposes and specifications. Published machining finish menus illustrate this variety, but the available treatment and its suitability still need to be confirmed for the actual material and part.[4]
Identify visible faces, sealing surfaces, electrical contact areas and any locations to mask or protect. Where color or texture matters, define the reference sample or acceptance method. A picture is useful context, but “make it look like this” leaves too much open when appearance is part of acceptance.
Ask the supplier to confirm whether the quoted process meets your dimensions before or after the specified treatment. Do not assume an as-machined measurement proves the final treated part will meet the drawing.
Before accepting a cost-saving change to a finish, ask what it changes in function, appearance and inspection. The same principle applies to features that are difficult to machine. Corner reliefs or revised geometry can be useful discussion points, but they require design approval rather than an undocumented substitution.[3]
Agree what the inspection report must show
“Inspection included” is not detailed enough when your receiving team expects a specific record. State which dimensions need reported results, the sample quantity, the reporting format and any material or processing records required. A marked drawing can help connect each result to the right feature.
Ask whether the required checks are made on the final part after relevant treatments, and whether any special fixture or measurement method needs agreement. A measured size and a geometric requirement are not interchangeable: the drawing must communicate which characteristic is being accepted.[1]
- Drawing
- Part number, revision and feature reference
- Result
- Specified characteristic and reported value
- Delivery
- Part or lot identity and agreed documents
Give delivery dates a clear starting point
Separate the requested quotation date from the required shipment or arrival date. Ask when the supplier’s lead-time estimate begins: after drawing release, material confirmation, sample approval or another agreed event. Record who must approve the next stage.
Include the destination city and country and any receiving or packaging constraints. Ask the supplier to identify what transport, taxes, duties or other delivery-related charges are included or excluded, rather than comparing totals with different scopes. Confirm exact commercial terms with the responsible purchasing team.
Use this email to request comparable quotes
The example below is deliberately specific about the files and open questions. Replace every bracketed entry and confirm that the message agrees with the attached drawing. Do not use the example part number or quantities unless they are appropriate to your project.
Subject: CNC machining RFQ — [part number], [revision], [quantities] Hello, Please quote the attached part using the following scope: Part and revision: [part number / description / revision] Files: [model filename] and [drawing filename] Material and condition: [grade / condition / specification] Quantities: [samples] and [production batch sizes] Forecast, if relevant: [quantity / period — not an order] Finish: [process / specification / areas to treat or mask] Critical requirements: [drawing feature references] Inspection: [reported dimensions / sample plan / records] Delivery: [destination / requested shipment or arrival date] Please identify the revision quoted and state: - Any assumptions, exclusions or questions about the files. - Unit prices and any separate setup or tooling charges. - Included inspection, treatment, packaging and delivery costs. - Estimated lead time and the event that starts it. - The proposed manufacturing site and any outside processing. Please quote the specified material and design as the base scope. List proposed alternatives separately for approval. Technical questions: [name / email] Purchasing contact: [name / email] Thank you, [name / company]
Agree confidentiality and the permitted file-transfer method before sharing sensitive project information. An inquiry form is not, by itself, a confidentiality agreement. Keep restricted technical data out of ordinary website uploads until the recipient and transfer arrangements have been confirmed.
Compare the quotation with your drawing—not just the total
When quotes arrive, put them beside the same part list and released files. Check the revision, material, quantities, finish, inspection and delivery scope line by line. A missing item should become a question, not an assumption that it is free or unnecessary.
If one supplier proposes a different route or material, ask for the effect on acceptance requirements and identify who must approve it. Compare the base quotes first, then review the alternatives separately. The Costs & Selection section brings together related guidance on scope comparisons and purchasing decisions.
For work involving several factories or processors, make the responsibilities explicit. At vetcnc, a discussion may lead to our own factories, a coordinated partner arrangement or a direct introduction. Ask who will manufacture, who will inspect and who is responsible for delivery before placing the order.
Check the package before you send it
Use these checks to review your inquiry. A checked box records your review only; it does not establish technical approval or guarantee that a supplier can make the part.
Local checklist only. Nothing is sent or saved between visits.
A clear inquiry is not the same as a finished design. It is a reliable starting point: the supplier can see what you need, ask about what is missing and return a quotation that you can evaluate against the same requirements.
Questions about your first CNC machining RFQ
Can I request a quote before every detail is final?
Yes—request a provisional estimate and identify the unsettled material, finish or feature requirements. Ask the supplier to list its assumptions. Confirm the final scope before placing an order or releasing production.
Should I send an assembly or individual part files?
Provide a part list and individual files for the components you want quoted. Add an assembly view when it helps explain interfaces or fit, and identify any purchased items that should not be included in the machining quote.
Does a drawing replace the written RFQ?
The drawing defines the technical requirements within its agreed scope. The RFQ also identifies quantities, delivery, reporting and commercial questions. Send a consistent package, and resolve disagreements between documents before proceeding.
Can I let the supplier choose an equivalent material?
Ask for a proposal rather than giving open-ended permission. Identify the exact alternative and review it against the design and customer requirements. Record approval before changing the material used for the order.
References
- ASME — Y14.5 Dimensioning and Tolerancing
- Protolabs — Understanding CNC Machining Tolerances
- Protolabs — How to Reduce CNC Machining Costs
- Protolabs — Surface Finishes for CNC Machining
External references explain technical concepts and are not endorsements or statements of vetcnc capacity. This article is general purchasing guidance; the agreed drawing, order and acceptance requirements govern the actual project.
About vetcnc
vetcnc brings a family manufacturing background to online CNC sourcing. Kevin has ten years of CNC industry experience and works with the family’s factories in China and a wider partner network. The aim is to make the manufacturing arrangement, technical requirements and responsibilities clear before an order is placed.
Read Kevin’s story →
