A356 Pump Housing RFQ Checklist: Pressure-Tight Requirements, Leak Test, Machining Datums, and PPAP Evidence

# A356 Pump Housing RFQ Checklist: Pressure-Tight Requirements, Leak Test, Machining Datums, and PPAP Evidence

Pump housings are not a generic "aluminum casting." They usually contain a sealing interface, a leak-risk boundary, machined datums that control assembly alignment, and an inspection or documentation package that decides supplier approval.

If you want quotes that are comparable (and do not collapse at launch), define the pressure-tight and machining reality up front.

Helpful Bohua routes:

• •A356 material route
• •Pump housing family overview
• •Pressure-tight pump housing RFQ route
• •Leak-tight casting route
• •Leak-test specification checklist
• •Formal RFQ upload

1) Define the pump housing function (what "pass" means)

Add, at minimum:

• •the fluid medium (oil, coolant, fuel, water, air, etc.)
• •operating pressure and temperature range
• •whether leakage is allowed at all, and what the consequence is (performance loss, safety risk, warranty risk)
• •whether the leak boundary is external-only, internal-only, or both

If you have a drawing note that says "leak tight," replace it with a quoteable requirement (next section).

2) Write a quoteable leak-test requirement (method + acceptance + sampling)

Suppliers will assume different methods and thresholds unless you state them.

Specify:

• •method (helium, pressure decay, mass flow, water immersion, etc.)
• •test pressure and hold time
• •stabilization time if required
• •acceptance threshold (leak rate or pressure drop over a defined time window)
• •sampling plan vs 100% testing, and when the rule changes (launch vs steady state)
• •whether impregnation is allowed, and how it must be recorded

If you do not know your final threshold yet, ask the supplier to propose assumptions and require that assumptions are written into the quote and first-article records.

Reference: Leak Test Specification for Pressure-Tight Aluminum Castings

3) Define sealing interfaces and “no-porosity zones”

Tell suppliers where porosity exposure is unacceptable:

• •sealing faces (gasket lands, O-ring grooves, machined flanges)
• •threaded ports and tapped holes that connect to the pressure boundary
• •bores or fits that must not leak along the interface

If you have a pressure boundary section view, include it. If you do not, call out sealing faces on the drawing and ask the supplier to flag any high-risk thick zones and feeding strategy assumptions.

4) Confirm the process route and heat treat assumptions

For A356 pump housings, buyers commonly compare gravity casting, low-pressure casting, and variants that change porosity risk and machining exposure.

Do not force an unverified route. Instead, ask the supplier to quote with:

• •process preference (if any) and why it is recommended for your geometry
• •heat treat state if required (for example, “A356-T6 per drawing” or “supplier recommendation”)
• •any property assumptions that matter for your program (pressure boundary behavior is driven by the whole process chain, not alloy name alone)

5) Define the machining scope (datums, sealing faces, ports, critical bores)

The fastest way to get uncomparable quotes is to send a pump housing drawing without machining context.

Include:

• •datum scheme for machining (A/B/C and which surfaces are functional)
• •list of machined features: bores, sealing faces, port threads, bearing seats, mounting faces
• •tolerance-critical relationships (coaxiality, perpendicularity, runout, true position)
• •surface roughness requirements where sealing matters
• •any post-machining leak test requirement (some programs test after machining)

If you only say “machining as required,” each supplier will assume a different operation list.

6) Specify the approval evidence package (what you need to sign supplier approval)

Choose the proof that matches the risk, not a random long list:

• •first article dimensional report (CMM or fixture report for functional datums)
• •material verification approach (MTC and/or spectro ticket expectations)
• •leak/pressure-test record format and traceability fields
• •X-ray / CT only if the program requires it (define zones and acceptance)
• •control plan / PFMEA / MSA if your program requires PPAP-style evidence

If you do not know what to ask for, start from the checklist: Quality Document Pack for Aluminum Casting RFQs

7) Include quantities and program timing (so tooling and sampling assumptions are visible)

State:

• •prototype quantity, pilot quantity, annual volume (and ramp plan if known)
• •destination and Incoterm preference (FOB, CIF, etc.)
• •whether tooling is new, existing, or transferring
• •target SOP timing (if you have one) and whether samples must pass a buyer-side validation plan

Copy-paste RFQ starter (A356 pump housing)

> A356 pump housing RFQ (pressure-tight)

> Files: 2D PDF rev __, STEP/IGES rev __

> Medium: __ ; operating pressure __ ; temperature range __

> Leak test: method __ ; pressure __ ; hold time __ ; acceptance __ ; sampling/100% __

> Sealing interfaces: gasket/O-ring faces __ ; no-porosity zones __

> Heat treat: per drawing __ / supplier recommendation __

> Machining: datums __ ; sealing faces __ ; ports/threads __ ; critical bores __ ; roughness __

> Inspection evidence: FAI __ ; CMM/fixture report __ ; material verification __ ; leak-test record fields __ ; PPAP elements (if required) __

> Quantity: prototype __ ; annual volume __ ; ramp __

> Destination + Incoterm: __

Start a structured pressure-tight pump housing RFQ

If you want the form to carry leak-test and pressure-tight context automatically, use the A356 pressure-tight pump housing RFQ route or upload through the formal RFQ page.