Quick answer
A comparable die casting quotation needs more than a CAD file. Give every supplier the same controlled drawing revision, alloy basis, annual and batch volumes, critical-to-function features, secondary-operation scope, validation records, packaging and delivery terms. Require assumptions and exclusions to be returned in writing.
- Buyer decision
- Is the quotation technically complete?
- Use this when
- Preparing or normalizing supplier RFQs
- Expected output
- A scope that can be compared line by line
A practical RFQ checklist for buying custom aluminum or zinc die cast parts from China, covering drawings, alloy, volume, tolerances, finish and validation.
Terms used in this guide
For this rfq preparation guide, the following terms keep drawing, quotation and supplier-review language consistent. The controlled project specification remains authoritative.
Controlled drawing
The released 2D document that governs material, tolerances, datums, finish, notes and revision.
Annual demand
Expected yearly quantity; it influences tool life, cavity count, automation and commercial assumptions.
Critical characteristic
A feature whose variation can affect safety, regulation, fit, sealing, motion or another important function.
Submission level
The agreed evidence required before release, such as dimensional results, material records or functional tests.
Decision summary
The decisions below establish the technical basis for rfq preparation guide before price or lead time is compared.
| Decision | What to define | Why it matters |
|---|---|---|
| Geometry authority | 3D model | Defines complete shape and tool-review geometry |
| Quality authority | Controlled 2D drawing | Defines datums, tolerances, notes, finish and revision |
| Capacity input | Annual demand + batch size | Influences cavity count, automation, inspection and packaging |
| Approval input | Reports + functional tests | Prevents late disagreement at sample release |
Control the drawing package
Send both a 3D model and a controlled 2D drawing. The model defines geometry; the drawing defines tolerances, datums, material, finish, notes and revision status. Mark dimensions that are critical to assembly instead of applying tight tolerances to every feature.
Identify appearance zones, sealing areas, bearing seats, threaded features and surfaces that cannot contain gates or ejector marks. If CAD and drawing revisions differ, state which file governs.
Define production and commercial assumptions
State prototype quantity, annual demand, expected batch size, target start of production and delivery location. These values affect cavitation, tool design, automation, inspection sampling and packaging.
Separate mandatory requirements from preferences. If a quotation must include tooling, machining, coating, gauges, reports, freight or export packaging, list each item so supplier comparisons cover the same scope.
Define approval evidence
List dimensional reports, material records, capability studies, appearance samples, pressure or leakage tests and packaging validation required before release. Provide the test method and acceptance limit.
A good RFQ reduces hidden assumptions. It also gives the supplier enough information to challenge avoidable cost before the mold is built.
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Technical deep dive
Build a quotation package that survives supplier handoffs
A good RFQ remains unambiguous when it moves from sales to tool design, casting, machining, finishing, quality and logistics.
Separate product requirements from supplier proposals
State what the finished part must do and which customer standards govern. Let the supplier propose gate position, press, cycle, fixtures and process controls unless the customer specifically controls them.
When a supplier proposal changes a drawing assumption—such as draft, wall thickness, machining stock or finish—capture it in a deviation list with owner and approval status.
Define tooling ownership and production obligations
State tool ownership, storage location, expected life, maintenance responsibility, replacement insert policy, sample quantities and what happens when demand ends.
For repeat export production, include change notification, record retention, spare-part support and the conditions under which the tool may be transferred or inspected.
Make sample approval measurable
List the characteristics and reports needed for first samples, but avoid demanding the same evidence for every low-risk dimension. Focus effort on functional datums, special characteristics, finish and tests.
State whether approval authorizes only the sample, the tooling condition or ongoing production. Define how later drawing, material, tooling or process changes trigger reapproval.
Evidence to request and retain
| Evidence group | Minimum useful record |
|---|---|
| Drawing package | Matching revision, material, datums, finish and notes |
| Scope matrix | Included, excluded, optional and pending items |
| Approval plan | Characteristic, method, quantity and acceptance limit |
| Commercial baseline | Tooling, piece price, packaging, delivery and terms |
RFQ information and the cost of leaving it undefined
These omissions create most of the commercial mismatch between two apparently similar quotations.
| RFQ input | What the supplier needs | If it is missing |
|---|---|---|
| Revision authority | Matching 3D and 2D files with revision/date | Tooling can be based on obsolete geometry |
| Volume profile | Prototype, annual volume and batch size | Wrong cavity, automation and tool-life assumptions |
| Secondary operations | Machining, finish, masking, cleaning and assembly | Low piece price hides incomplete scope |
| Approval evidence | Characteristics, method, frequency and report format | Sampling and validation costs appear after nomination |
| Delivery basis | Destination, Incoterm, packaging and labeling | Supplier prices are not commercially comparable |
Failure modes and controls
For rfq preparation guide, each risk below is tied to a cause, product consequence and measurable prevention or validation control.
| Risk | Typical cause | Possible consequence | Recommended control |
|---|---|---|---|
| Conflicting revisions | Model and drawing do not match | Supplier quotes the wrong geometry | Name the governing revision and close discrepancies before tooling |
| Unbounded tolerances | General tight tolerances applied everywhere | Costly machining and inspection without functional value | Mark only assembly-critical characteristics and datum relationships |
| Missing finish scope | Color or coating named without masking and tests | Threads, seals or cosmetics fail after finishing | Define visible zones, masked areas, thickness and acceptance method |
| Undefined volume | Only sample quantity is supplied | Tool concept and unit-cost assumptions are misleading | Provide prototype, annual demand, batch size and program life |
| Unequal quote scope | Suppliers include different secondary operations | Prices cannot be compared | Use a line-item scope for tool, part, machining, finish, reports and packaging |
Recommended engineering workflow
Apply this sequence to the rfq preparation guide and record unresolved assumptions at every gate so later operations do not optimize against different requirements.
- 01Freeze the model and drawing revision
- 02Mark functional datums and special characteristics
- 03State alloy standard and approved alternatives
- 04Define annual demand, batches and delivery location
- 05List machining, finish, testing and documentation
- 06Require assumptions and exclusions to be returned with the quotation
Buyer and engineering guidance
How an overseas buyer should normalize quotations from China
Ask every China die casting supplier to return a scope matrix with included, excluded and pending items. Tooling ownership, trial quantity, machining fixtures, gauges, coating, first-article reports, export packaging and freight should be separated instead of buried in one total.
Review technical deviations before ranking price. A supplier that exposes a draft conflict or unrealistic tolerance may look slower at first, but the clarification often prevents a costly mold correction.
Freeze the commercial baseline only after engineering, quality and purchasing agree on the same deliverables. Record later changes against that baseline so a price revision has a visible technical reason.
Application example
Example: quoting a machined control enclosure
A useful package would identify the enclosure alloy, gasket land, connector openings, internal mounting bosses, annual volume and coating system. The drawing would separate as-cast walls from machined interfaces and mark the surfaces that must remain free of coating.
The quotation can then separate tooling, casting, CNC machining, masking and coating, first-piece inspection, packaging and delivery. Purchasing compares the same scope, while engineering can see which assumptions still require approval.
Engineering and purchasing checklist
Use this rfq preparation guide checklist during design review, quotation and sample approval; add any customer-specific regulatory or functional controls.
- 3D model and controlled 2D drawing use the same revision
- Alloy standard and permitted alternatives are stated
- Prototype quantity, annual demand and batch size are separated
- Critical datums, appearance zones and functional tests are marked
- Tooling, machining, finishing, reports and packaging are included in the quoted scope
Frequently asked questions
Can a 3D model alone be quoted?
A model can support an early review, but a controlled drawing is needed to define tolerances, datums, material, finish, notes and revision authority.
Why does annual volume matter before tooling?
Volume affects cavity count, tool life, automation, cycle assumptions, inspection sampling and the economics of secondary operations.
What causes quotations to be difficult to compare?
Different assumptions about tooling ownership, machining, coating, inspection reports, packaging or delivery terms can create a false price comparison.
Standards and technical references
For this rfq preparation guide, use the current contract edition of each source. These references support review terminology but never replace the controlled drawing or written supplier agreement.
Technical review and revision record
- Technical reviewer
- Huabo Technical Team
- Content owner
- Cixi Huabo Machinery Co., Ltd.
- Engineering basis
- Huabo manufacturing experience, current capability evidence, cited standards and drawing-based production practice
- Reviewed
- 26 August 2026
- Review trigger
- Recheck when equipment, certification, process scope, cited standards or product evidence changes
- Project limitation
- Customer drawings, specifications and written approval records remain the authority for every production commitment
Huabo Technical Team reviews the manufacturing guidance as an organizational technical record. This review does not replace project-specific DFM, customer approval or the controlled drawing for any component.
Drawing-based review
Discuss this requirement with Huabo engineering.
Send the controlled drawing, alloy, annual demand, critical dimensions, finish and validation requirements.