An accurate aluminum CNC quote starts with a controlled technical package. Send aligned files, exact requirements, realistic quantities, and one commercial scope.
This reduces clarification rounds and exposes differences between supplier quotes. It also protects critical requirements during DFM review.
Aluminum CNC machining RFQ checklist
| RFQ field | State clearly | Why the supplier needs it |
|---|---|---|
| Part identity | Part number, name, revision | Prevents obsolete-file use |
| Design files | STEP model and controlled 2D PDF | Separates nominal geometry from acceptance requirements |
| Material | Alloy, temper, and product form | Controls sourcing and process assumptions |
| Critical features | Datums, tolerances, GD&T, threads, inserts | Directs machining and inspection effort |
| Finish | Process, color, texture, masking, cosmetic zones | Defines post-machining acceptance |
| Quantity | Prototype, pilot, production tiers, annual demand | Reveals setup and volume effects |
| Quality | Inspection scope and required records | Makes approval evidence quoteable |
| Delivery | Required date, destination, packaging | Defines the actual supply scope |
| Commercial terms | Currency, freight basis, payment, validity | Makes quotes comparable |
| DFM permission | Protected requirements and allowed alternatives | Enables savings without uncontrolled changes |
Use the checklist as a cover sheet. The sections below explain how to control each field.
Start with one controlled technical data package
A supplier cannot quote responsibly from a photo or part name. Send the files needed for programming, interpretation, and inspection.
The 3D model should define nominal geometry. STEP is widely accepted for exchanging solid-model data between different CAD systems.
The 2D PDF should define requirements that the model cannot communicate reliably. These usually include tolerances, datums, GD&T, threads, finishes, and inspection notes.
State which file controls if a conflict appears. For example, the model may control nominal geometry while the drawing controls acceptance requirements.
Apply one revision identifier across every related file. Include that revision in the RFQ subject and attachment names.
An assembly view can clarify interfaces without becoming the manufacturing authority. Mark reference-only files clearly.
Use a recognized drawing standard when GD&T controls fit or inspection. ASME Y14.5 provides the common language for stating and interpreting those controls.
Before sending, remove obsolete files from the package. A clean package is safer than an email explaining which attachment to ignore.
Specify the aluminum alloy, temper, and starting stock
“Aluminum” is not a material specification. State the alloy and temper, such as 6061-T6 or 7075-T6.
Also state the required product form. The supplier may need billet, plate, bar, tube, or a custom extrusion.
Product form can affect grain direction, stock availability, certification, waste, and process planning. Do not let each bidder assume a different starting point.
If an equivalent material is acceptable, define the approval rule. Require written approval before substitution when material affects strength, appearance, compliance, or mating performance.
State who supplies the raw stock. Add any mill certificate, traceability, country-of-origin, or restricted-substance requirements.
Do not request documents that the project does not need. Every certificate adds scope that the supplier must price and manage.
Identify functional tolerances and inspection requirements
Blanket tight tolerances rarely improve a design. They can increase machining, setup, and inspection effort across noncritical surfaces.
Start with the features that control function. These may include bearing fits, sealing faces, locating holes, datum surfaces, threads, and assembly interfaces.
For each critical feature, define the requirement and inspection method. Then leave noncritical dimensions under an agreed drawing standard or supplier default.
Do not assume that two suppliers use the same default tolerance. Ask each bidder to state the standard and any exceptions in the quote.
Surface roughness belongs only on surfaces that need it. Connect each roughness callout to sealing, sliding, appearance, coating, or another functional reason.
Threads need more than a diameter. State the standard, pitch, class, depth, and insert requirement where applicable.
If a dimension applies after anodizing or coating, say so. Otherwise, suppliers may inspect the machined condition while you expect the finished condition.
Define surface finish as an acceptance requirement
“Black anodized” is usually incomplete. The RFQ should describe the process and the accepted result.
State the anodizing, conversion coating, plating, painting, powder coating, blasting, or polishing requirement. Add the governing specification when one applies.
For color, provide a controlled reference. A named color alone may not define an acceptable range between batches.
Mark cosmetic surfaces on the drawing. Define whether tool marks, scratches, dents, rack marks, and color variation are acceptable there.
Show masking zones for threads, electrical contacts, grounding points, sealing faces, and precision fits. Identify any dimensions that apply after finishing.
If a texture matters, name the process and reference sample. Words such as “smooth” and “premium” are not measurable acceptance criteria.·
Coordinated machining and aluminum surface treatments can reduce handoffs. The RFQ still needs separate machining and finish acceptance rules.
Quote quantity, production stage, and required dates
State the immediate order quantity and the expected production stage. A prototype quote serves a different decision than a repeat-production quote.
Request price breaks that match real purchasing scenarios. For example, ask for prototype, pilot, and production quantities that your team may actually order.
Provide estimated annual volume when it can affect process planning. Label forecasts as estimates rather than purchase commitments.
Use a required delivery date instead of “ASAP.”
Add the ship-to location. Say whether the date means ship date or arrival date.
If qualification comes first, show the sequence. A clear sample-approval gate prevents suppliers from pricing full production under different assumptions.
Match quality records to part risk
Inspection requirements should reflect the consequence of failure. A cosmetic cover and a flight-critical bracket should not carry the same evidence burden.
State which dimensions require recorded results. Identify the sampling plan, inspection equipment, and report format when these details matter.
Common records include a Certificate of Conformance, material certificates, First Article Inspection, and CMM reports. Request only the records needed for approval and traceability.
Define the approval path for nonconforming results. The supplier should not change a tolerance, material, or finish through an undocumented concession.
If a golden sample controls appearance, identify its owner and revision. Explain how the sample will be stored and compared.
Fix the commercial and logistics scope
Two unit prices are not comparable when they include different freight, packaging, or inspection. Define the commercial boundary before evaluating bids.
State the quote currency, payment terms, quote validity, ship-to address, and packaging requirements. Add customs documents, tariff codes, or origin statements when required.
For international sourcing, name the agreed delivery place with an Incoterms® 2020 Rule. This helps both parties allocate cost, risk, and delivery obligations consistently.
Do not write only “FOB” or “DDP.” Include the named place and the applicable rules edition.
Add confidentiality and file-security requirements before releasing sensitive models. State any export-control or restricted-access obligations in the RFQ.
Invite DFM alternatives without surrendering design control
DFM can reduce machining time, setups, waste, and inspection. It should not silently change a functional requirement.
Separate requirements into three groups:
- Protected: interfaces, critical dimensions, material performance, approved finishes, and regulatory needs.
- Negotiable: noncritical radii, tool access, cosmetic areas, or stock allowances.
- Alternative proposal: any supplier change requiring written approval before production.
Ask the supplier to quantify each proposal’s effect on price, lead time, quality, and validation. The original compliant quote should remain visible where practical.
Part geometry and volume may justify billet machining or an extrusion-plus-CNC route. Invite a priced alternate when both routes could meet the same acceptance requirements.
Do not prescribe an axis count without a functional reason. Ask for the proposed setup, datum strategy, and risk controls instead.
Geometry, setup count, tolerance, and finishing influence aluminum CNC machining cost. Controlled alternatives reveal savings without weakening the design.
Normalize supplier quotes before selecting one
The lowest visible unit price may exclude finish, inspection, packing, or freight. Normalize every bid against the same requested scope.
Use a matrix like this during bid review (You need to fill in the blank sections of the form based on the supplier’s quote):
| Comparison field | Quote A | Quote B | Quote C | Evaluation rule |
|---|---|---|---|---|
| Material and product form | Match alloy, temper, origin, and certificates | |||
| Setup or non-recurring engineering (NRE) | Separate one-time from recurring cost | |||
| Unit-price tiers | Compare identical quantities | |||
| Finishing | Match process, masking, color, and acceptance | |||
| Inspection and records | Match reports and sampling | |||
| Packaging | Match protection and labeling | |||
| Freight and delivery term | Compare the same named place | |||
| Lead time | Separate sample and production stages | |||
| Tooling ownership | Record ownership, life, storage, and replacement | |||
| Assumptions and exclusions | Close every material difference in writing | |||
| Quote validity | Confirm the award window |
Ask suppliers to revise unclear bids. Do not “correct” their assumptions privately in a buyer spreadsheet.
Copy-ready RFQ template
Copy this structure into your sourcing system or email. Replace every bracketed field before sending.
Subject: RFQ – [Part name] – [Part number] – Revision [X]
1. Buyer and project
- Company: [Name]
- Contact: [Name, role, email, phone]
- Application/end use: [Short functional context]
- Confidentiality or export controls: [Requirements]
2. Controlled technical package
- 3D model: [Filename and revision]
- 2D drawing: [Filename and revision]
- File authority: [Model controls nominal geometry; drawing controls requirements]
- Reference-only files: [Assembly, photos, specifications]
3. Material
- Aluminum alloy and temper: [Grade]
- Product form: [Plate, bar, billet, tube, custom extrusion]
- Approved equivalents: [None, or written-approval rule]
- Material records: [Mill certificate, traceability, origin]
4. Machining and acceptance
- Critical features/datums: [Drawing references]
- Tolerances/GD&T standard: [Standard and edition]
- Threads/inserts: [Requirements]
- Surface roughness: [Critical surfaces only]
- Inspection: [Features, sampling, report, equipment]
5. Surface finish
- Process/specification: [Requirement]
- Color/texture reference: [Reference]
- Masking and cosmetic zones: [Drawing references]
- Post-finish dimensions: [Drawing references]
- Finish records: [Required certificates or test results]
6. Quantity and schedule
- Prototype quantity: [Qty]
- Pilot quantity: [Qty]
- Production quantity or annual demand: [Qty]
- Required sample date: [Date and meaning]
- Required production date: [Date and meaning]
7. Commercial and logistics
- Currency: [Currency]
- Delivery term and named place: [Rule, place, edition]
- Ship-to address: [Address]
- Packaging/labeling: [Requirements]
- Payment terms: [Terms]
- Quote validity: [Days or date]
8. Requested quotation breakdown
- Setup/NRE and tooling
- Unit prices for each quantity tier
- Material, machining, finishing, inspection, packaging, and freight
- Sample and production lead times
- Tooling ownership and replacement terms
- Assumptions, exclusions, and capacity constraints
9. DFM and alternatives
- Protected requirements: [List]
- Negotiable features: [List]
- Quote compliant scope first: [Yes/No]
- Price approved alternatives separately: [Yes/No]
- Show cost, lead-time, quality, and validation effects: [Yes/No]
10. Response
- Clarification deadline: [Date]
- Quote due date: [Date]
- Submission method: [Email or portal]
Final check before sending
- Confirm every model, drawing, and specification uses the correct revision.
- Remove obsolete attachments and label reference-only files.
- State alloy, temper, product form, and substitution rules.
- Mark critical features, datums, threads, and post-finish dimensions.
- Define finish, color reference, masking, and cosmetic acceptance.
- Request realistic quantity tiers and stage-specific dates.
- Match inspection records to actual part risk.
- Fix currency, packaging, destination, and delivery scope.
- Protect functional requirements while inviting priced alternatives.
- Require assumptions and exclusions in writing.
A complete RFQ gives suppliers enough information to quote one controlled scope. It also gives your team a defensible basis for award.
Zheng Ji supports aluminum CNC projects from prototypes through production. Its 30 CNC machines cover 3-axis, 4-axis, and 5-axis work.
Send the controlled package through Zheng Ji’s aluminum CNC machining service. The engineering team can review it and return a quote within 24 hours.
Standard lead time is about 20 days, depending on volume and complexity. Confirm the actual schedule in the written quote.
