Buyer Resource
Drawing Requirements for Casting RFQs
Which drawings and part details make a casting RFQ easier to review? This guide covers 2D and 3D drawing expectations, revision notes, part geometry context, material preference, surface notes, and volume information that help a supplier prepare a useful response.
Drawing Files
2D drawing and 3D model expectations
A 2D drawing in PDF format and a 3D model in STEP or IGES format are the most useful starting point for a casting RFQ. The 2D drawing communicates tolerances, GD&T callouts, surface finish requirements, and critical feature notes. The 3D model helps the supplier review wall sections, draft angles, undercuts, and parting line strategy.
If only a 2D drawing is available, that is still a usable starting point. The supplier can ask targeted questions about wall thickness and overall geometry before confirming the process route and tooling approach. A 3D model reduces the number of clarification rounds needed before quoting.
DWG, IGES, and compressed ZIP packages containing multiple files are also accepted. When sending multiple files, include a note describing which file is the primary drawing and which are reference documents.
Revision Control
Revision control and critical notes
Include the drawing revision number and issue date in the file or in the RFQ message. If the drawing is marked preliminary, for-review, or subject to change, note this clearly so the supplier can flag assumptions that may need to be revisited before tooling is ordered.
Highlight critical dimensions, sealing surfaces, datum scheme, and any features that directly affect secondary operations setup or quality review planning. Marking these on the drawing — rather than describing them in a separate message — reduces the risk that important requirements are missed during review.
Part Geometry
Part weight, envelope size, and assembly context
Part weight estimate and envelope dimensions help the supplier assess casting machine fit, tooling size, and handling requirements. These details are especially useful when the 3D model is not yet available or when early process feasibility feedback is needed before the drawing is finalized.
If the part fits into an assembly, a brief description of the mating components and the functional interface helps the supplier understand which dimensions and surfaces carry the highest design risk. Assembly context is also useful for identifying which features need precision secondary operations versus cast-to-size finish.
Material
Material preference or open review
If the alloy is fixed by engineering specification, state it in the RFQ message. If the alloy choice is open, describe the mechanical requirements — tensile strength range, elongation target, or hardness specification — so the supplier can recommend a casting approach and alloy combination that meets the application need.
Heat treatment requirement, if applicable, should also be noted at the RFQ stage. T5 and T6 heat treatment changes the mechanical property range and adds to cycle time and cost. Including this in the initial package avoids a revision round after the tooling discussion has started.
Surface and Secondary Operations
Surface and secondary-operation notes
Surface treatment scope, coating type, and secondary operation requirements are often left out of the first RFQ message. Including them upfront — even as a preliminary note — gives the supplier a more complete picture of the total part cost and delivery scope.
Common surface treatment options include powder coating, shot blasting, anodizing, and painting. If the part requires secondary operations for sealing surfaces, threads, ports, or dimensional-critical features, note the secondary operation scope alongside the casting drawing so both are reviewed together.
Volume Estimate
Annual volume or launch-stage estimate
Annual volume range and project stage help the supplier select a tooling type and production approach that fits the program. A range estimate is sufficient at the RFQ stage. For launch or pilot programs, note whether first-article approval, a supplier qualification submission, or a pre-production sample review is part of the expected scope before production release.
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FAQ
Buyer questions about casting drawing requirements
What files should I send with an aluminum casting RFQ?
A 2D drawing in PDF format and a 3D model in STEP or IGES format give the supplier what is needed to review geometry, wall sections, draft angles, and secondary operation scope. If only a 2D drawing is available, it is still a useful starting point for a process discussion.
Can I request a review before the drawing is final?
Yes. A preliminary or for-review drawing can support an early process discussion. Mark the revision status clearly and note which dimensions are still subject to change. Early DFM input on wall thickness, draft, and parting line can reduce revision cycles before tooling is ordered.
What if I am unsure which casting process fits the part?
Send part weight, envelope size, wall section range, and estimated annual volume. A supplier can suggest a casting approach and explain the fit. See the casting process selection guide for a discussion of common casting approaches.
Should I include quantity range and project stage?
Yes. Annual volume range and project stage (prototype, pilot, production) affect tooling type, cycle time approach, and pricing. A range estimate is enough — an exact production forecast is not required for the initial RFQ review.
Can photos or existing samples help the review?
Yes. Photos of reference parts or existing castings help the supplier understand surface quality expectations and geometry intent when drawings are incomplete. If replacing a part from another supplier, a sample or reference casting alongside the drawing is especially useful.