Casting + CNC Machining RFQ Checklist for Housings

# Casting + CNC Machining RFQ Checklist for Housings

Housing RFQs often look simple at first. The buyer has a drawing, a model, a quantity target, and a sourcing need. The supplier reviews the files and sends a quote.

In practice, a housing RFQ usually contains two connected questions. First, how should the part be cast? Second, which features need CNC machining after casting? If the RFQ does not separate those two scopes, suppliers may quote different assumptions and the buyer may receive numbers that are hard to compare.

This checklist is for buyers preparing aluminum housing RFQs for pumps, gearboxes, motors, industrial equipment, and similar assemblies. It helps the buyer state what is known, what is open, and what the supplier should review before quotation.

Send both 2D and 3D files when possible

A 3D model helps the supplier understand geometry. A 2D drawing defines requirements, notes, tolerances, datums, and revision status. When the two files are both available, send both.

If only one file type is ready, say so directly. The supplier can still begin a feasibility review, but the quote should list which assumptions were made because of missing files.

Useful file notes include:

• •file type and drawing revision
• •whether the model and drawing match
• •whether dimensions are final or still under review
• •which file should control if there is a conflict
• •whether the supplier should comment on manufacturability

For broader drawing-package guidance, see Bohua's casting drawing requirements.

Mark the functional features

Not every surface on a housing has the same importance. Some surfaces are cosmetic. Some are assembly features. Some locate other components. Some only need to be cleaned after casting.

The RFQ should identify the functional features that drive cost and planning. Examples include:

• •mounting faces
• •bearing or bushing areas
• •threaded holes
• •datum surfaces
• •sealing faces
• •locating bosses
• •cover interfaces
• •ports or openings
• •surfaces that affect assembly fit

This does not require a long explanation. A simple note such as "critical assembly features are marked on drawing sheet 2" can save review time.

Separate as-cast features from CNC scope

One of the most common RFQ problems is unclear scope. If the buyer expects the supplier to deliver a fully machined casting, say that. If the buyer only needs a raw casting, say that too. If the buyer is comparing both options, request two quote lines.

A clear RFQ package can use a scope table:

• •raw casting only
• •casting plus CNC machining
• •casting plus finish operation
• •casting plus packaging requirement
• •optional scope for later review

This helps the supplier avoid quoting a partial scope when the buyer expects a finished component. Bohua's CNC machining capability page can help buyers frame machining scope alongside casting scope.

Define datum and setup expectations

For housings, machining scope often depends on how the part is located during setup. The supplier needs to know which datums matter and whether the drawing already defines them clearly.

If datum information is incomplete, the buyer can still ask the supplier to propose a practical datum plan. The quote should then state that the plan is a quotation assumption and must be confirmed before production release.

Helpful RFQ notes include:

• •primary datum surfaces
• •features that must align with each other
• •bore or face relationships
• •flatness or perpendicularity notes
• •whether the drawing needs supplier feedback

Be clear about threads and inserts

Threads are easy to underestimate in an RFQ. Buyers should identify whether holes are cast, drilled, tapped, or left for later operations. If inserts are required, list the insert type or ask the supplier to quote it as an open item.

Useful details include:

• •thread size
• •thread depth
• •through hole or blind hole
• •insert requirement if any
• •post-process cleaning expectations
• •whether thread gauges or records are required

State surface finish expectations by area

Surface finish should not be treated as one global requirement unless the whole part truly needs the same finish. A housing may have raw exterior areas, machined assembly faces, threaded features, and visual surfaces with different expectations.

If a surface requirement is important, mark it on the drawing. If it is only a preference, label it as a preference. That distinction helps the supplier quote the right scope instead of overbuilding the estimate.

Include quantity and order pattern

Quantity affects planning even when the geometry stays the same. The RFQ should separate sample quantity, first order quantity, and expected annual range when those numbers are known.

If the forecast is uncertain, a range is acceptable. A supplier can work with uncertainty if the uncertainty is visible. For product examples, buyers can browse Bohua's aluminum casting products catalog before preparing a part-specific RFQ.

Ask the supplier to list assumptions

A useful quote should not be only a price. It should also state what the supplier assumed. Buyers should request written assumptions for:

• •drawing revision
• •material basis
• •casting scope
• •CNC scope
• •surface finish scope
• •packaging basis
• •quantity range
• •open drawing questions

This makes supplier comparison easier. It also gives the buyer a cleaner path to revise the RFQ if assumptions change.

Keep questions visible

If the buyer already knows there are unresolved questions, list them in the RFQ. Examples include an unfinished drawing revision, uncertain annual demand, optional finish, or an assembly feature that may change.

Open questions do not make an RFQ weak. Hidden questions do. A clear open-item list helps the supplier respond with the right technical and commercial notes.

Bottom line

A housing RFQ is easier to quote when casting scope and CNC scope are separated. Buyers should send the drawing and model, mark functional features, identify datums, define threaded features, state surface finish expectations, and ask the supplier to list assumptions.

If you are preparing a cast aluminum housing RFQ, Bohua can review the drawing package and help clarify the quotation assumptions before the project moves forward. Have a housing drawing ready for review? Send the PDF, STEP file, expected quantity range, and open scope questions through the RFQ form.

FAQ

Should I send both a PDF drawing and a 3D model?

Yes, when both are available. The model helps geometry review, while the drawing defines requirements, notes, revision status, and tolerance expectations.

What if I do not know the final CNC scope yet?

State the open scope directly. You can ask for one quote line for raw casting and another for casting plus CNC machining if both options are under review.

Why do datums matter in a housing RFQ?

Datums affect how features are located and how the supplier plans post-casting operations. If datum notes are unclear, ask the supplier to list assumptions.

What should I ask the supplier to include in the quote?

Ask for drawing revision, material basis, casting scope, CNC scope, surface finish scope, quantity basis, and open technical assumptions.