A complete CNC machining RFQ checklist helps a machine shop understand what must be made, what must be inspected, and which requirements can affect the machining route. This guide covers the information an engineer or buyer should send when requesting custom milled or turned parts.
You do not need to prepare a long document. A controlled drawing, a usable 3D model, and a short list of commercial requirements are usually more useful than several disconnected messages.
If you also need to understand why quotations differ, review our CNC machining cost guide covering material, geometry, tolerances, quantity, finishing and inspection.
Download the CNC Machining RFQ Checklist
Use this three-page PDF to organize drawing files, material, quantity, tolerances, finishing, inspection and delivery requirements before sending an RFQ.
CNC Machining RFQ Checklist
Include the following information whenever it applies to your project:
- Part name and part number
- Drawing revision
- 3D CAD file and controlled 2D drawing
- Material grade and condition
- Required quantity
- Critical dimensions and tolerances
- Surface finish and edge requirements
- Threads, inserts, and assembly requirements
- Inspection and documentation requirements
- Delivery destination and requested date
1. Part Name, Part Number, and Revision
Use a unique part number for each component. If a drawing changes, include the revision so the quotation and later production discussion refer to the same specification.
Avoid sending several files with nearly identical names such as “final,” “final-new,” and “final-latest.” A simple controlled naming system reduces the chance of reviewing the wrong version.
Useful information:
- Part name
- Part number
- Drawing revision
- RFQ reference or project reference
- Quantity for each part number
2. Send Both a 3D CAD File and a 2D Drawing
The 3D model communicates the part geometry. The 2D drawing communicates requirements that may not be fully defined by the model, including tolerances, threads, surface finish, datum structure, and inspection notes.
Common exchange formats include STEP for the model and PDF for the drawing. Native CAD files may also be useful when both parties agree on a compatible format. Therefore, before sending files, confirm that the drawing revision matches the 3D model.
3. Specify the Material Grade and Condition
Do not write only “aluminum,” “steel,” or “plastic.” Different grades can machine, finish, and perform differently.
For example, clearer material descriptions include:
- Aluminum 6061-T6
- Aluminum 7075-T6
- Stainless steel 304
- Stainless steel 316
- POM / acetal with the required color
- Nylon with the required grade or reinforcement
In addition, if material certificates or traceability documents are required, state that in the RFQ. Availability and documentation should be confirmed before quotation.
Review our CNC machining materials and surface finishes page when comparing common options.
4. State Prototype and Production Quantities
Quantity can affect material purchasing, workholding, programming, inspection planning, and the most practical production approach.
For example, if the project may move from prototypes to repeat production, provide both quantities when possible. For example:
- Prototype quantity: 2 pieces
- Expected repeat quantity: 50 pieces per release
However, this does not commit the buyer to a future order. It simply helps the supplier understand the likely project stage.
For low-volume requirements, see our small-batch CNC machining capabilities.
5. Identify Critical Dimensions and Tolerances
Not every feature needs the same tolerance. Mark the dimensions that affect fit, motion, sealing, alignment, or assembly.
For example, useful drawing information may include:
- Datum references
- Fits for shafts, bores, or bearings
- Positional requirements for hole patterns
- Flatness, perpendicularity, or parallelism where function requires it
- Thread specifications
- Mating dimensions
Over-tolerancing non-critical features can add unnecessary machining and inspection effort. When a requirement is functional, explain the mating or assembly condition if that context can be shared.
Read more about CNC machining tolerances and inspection requirements.
6. Define Surface Finish and Edge Requirements
State whether the part will remain as-machined or receive a secondary finish. If appearance matters, identify cosmetic surfaces on the drawing.
Depending on the material and application, requirements may include:
- As-machined surface
- Anodizing
- Passivation
- Polishing
- Plating
- Powder coating
- Bead blasting
- Heat treatment or hardening
In addition, define deburring, sharp-edge, and corner requirements. If an exact edge break or radius is functionally important, dimension it instead of relying only on a general note.
7. Include Threads, Inserts, and Assembly Notes
Thread callouts should identify the standard, size, pitch, class or tolerance when applicable, and required depth. Distinguish between thread depth and drilled depth.
Furthermore, if the supplier must install threaded inserts, dowel pins, or other hardware, include:
- Hardware specification
- Installation location
- Required orientation
- Whether the hardware is supplied by the buyer or the machine shop
- Any assembly or torque requirement that must be reviewed
8. Define Inspection and Documentation
Inspection requirements should match the part function and purchasing requirements. Mark critical characteristics and state what evidence is required with the shipment.
Possible requirements include:
- Standard dimensional inspection
- First article inspection
- Critical-dimension report
- CMM inspection for suitable features
- Material documentation
- Surface-treatment documentation
- Lot or part identification
Therefore, do not assume that every document is automatically included. List the required records in the RFQ so their availability and scope can be reviewed.
Learn more about our quality and inspection approach.
9. Provide Delivery Information
Include the destination country or postal code and the requested delivery date. This allows the supplier to separate manufacturing requirements from shipping expectations.
Finally, if the date is connected to an assembly build, test, or customer milestone, state whether it is a preferred date or a firm requirement. Feasibility should be confirmed after the drawing, material, quantity, finishing, and inspection scope have been reviewed.
10. Protect Confidential Information
To protect the project, share only the information needed to quote and manufacture the part. Remove unrelated customer data from drawings and models. If an NDA is required before technical review, state that before uploading confidential files.
RFQ Information Summary
| Category | What to provide |
|---|---|
| Part identity | Part name, part number, and revision |
| Geometry | 3D CAD model and controlled 2D drawing |
| Material | Exact grade, condition, color, and required documentation |
| Quantity | Prototype and expected repeat quantities |
| Tolerances | Critical dimensions, datums, fits, and geometric requirements |
| Finish | As-machined or secondary finish, cosmetic surfaces, and edge notes |
| Hardware | Threads, inserts, supplied components, and assembly requirements |
| Inspection | Critical characteristics and required reports or certificates |
| Delivery | Destination and requested date |
| Commercial | Contact details and RFQ/project reference |
What Happens After You Submit the RFQ?
The supplier should review the drawing and model for material, geometry, machining access, workholding, finishing, and inspection needs. The supplier may raise technical questions before finalizing a quotation.
Part geometry determines whether CNC milling, CNC turning, or a combination of operations is appropriate. In addition, compare available machine travel and setup constraints with our equipment and capacity information.
Frequently Asked Questions
Can I request a quote without a 2D drawing?
A 3D model may be enough for an initial geometry review, but a 2D drawing is recommended when the part has critical tolerances, threads, surface requirements, datums, or inspection notes.
Which CAD format should I send?
STEP is a commonly used neutral format for 3D geometry. A PDF drawing can accompany the model. If you need to send another format, identify it before submission.
Should I specify a general tolerance?
In addition, if a general tolerance standard applies, identify it on the drawing. Critical or function-related features should still be clearly marked rather than left only to a general note.
What information is needed for a repeat order?
Provide the original part number, current revision, required quantity, and any approved change. Confirm whether material, finish, inspection, packaging, or delivery requirements have changed.
Request a CNC Machining Quote
Send your drawing, CAD file, material grade, quantity, finish, critical tolerances, inspection requirements, and delivery destination for review.