Pump Housing Leak Test RFQ Requirements: What Buyers Should Specify

# Pump Housing Leak Test RFQ Requirements: What Buyers Should Specify

Leak testing is one of the easiest pump-housing requirements to write vaguely and one of the hardest to fix after tooling. A drawing note that says "leak test required" does not tell the casting supplier the test medium, pressure, duration, acceptance threshold, sampling plan, or record format. The result is predictable: suppliers quote different assumptions, buyers compare unequal prices, and production launch gets delayed when inspection expectations surface too late.

This checklist helps buyers write pump housing leak-test requirements into the RFQ package. It is relevant for aluminum pump housings, valve bodies, fluid-path castings, and similar pressure-sensitive components. For supplier context, see Bohua's pump housing manufacturer page and quality control page.

Start with the function, not the test method

Before naming a test, describe the part function:

• •fluid type or gas type
• •normal operating pressure
• •peak pressure or proof pressure
• •operating temperature range
• •whether leakage is a safety issue, performance issue, or cosmetic issue
• •which surfaces are sealing surfaces
• •whether the casting is tested before or after machining

A supplier cannot choose the right test method until the use case is clear. A low-pressure coolant housing, a hydraulic valve body, and a vacuum-pump chamber all need different assumptions.

The six RFQ fields that matter most

1. Test medium

State whether the test uses air, water, helium, nitrogen, oil, or another medium. Air tests are common for production screening. Water or pressure-bath tests help reveal visible bubbles. Helium testing is more sensitive but also more expensive and requires controlled fixtures.

Do not let suppliers choose the medium silently. A quote based on air decay is not the same as a quote based on helium mass spectrometry.

2. Test pressure

Specify test pressure and whether it is related to working pressure or proof pressure. Write the units clearly: bar, kPa, psi, or mbar. If the test pressure is not yet frozen, state the design assumption and ask the supplier to quote the test fixture as a separate line.

For early RFQs, a useful note is: "Supplier to propose leak-test method and pressure based on working pressure and drawing geometry; final value to be confirmed before tooling release."

3. Hold time or measurement window

A pressure-decay test without time is incomplete. State the stabilization time and measurement time when known. If not known, ask the supplier to propose a method. The same part can pass a short screening test and fail a longer hold test.

4. Acceptance criteria

Define the maximum allowed leakage rate or pressure drop. Examples:

• •maximum pressure loss over a defined time
• •maximum leak rate in sccm
• •no visible bubbles in water bath during a defined hold time
• •no through-leak at sealed port surfaces

Avoid phrases like "no leakage" without method and threshold. In production, acceptance must be measurable.

5. Sampling plan

State whether testing is required for every part, first article only, each batch, or a sampling plan such as one part per cavity per shift. Pressure-sensitive pump housings often need higher inspection coverage than decorative brackets, but the final plan depends on risk and cost.

If the buyer requires full inspection, state whether records are needed for every serial number or only batch-level confirmation.

6. Traceability and records

Leak-test data is useful only if it connects to production identity. Define what record the supplier must retain:

• •part number and revision
• •batch number or serial number
• •fixture ID
• •operator or station ID
• •test medium
• •test pressure
• •time window
• •result and acceptance threshold
• •nonconforming action

For PPAP or customer approval, include the desired report format before quotation.

Where leak risk enters the casting process

Leak problems are not only inspection problems. They can enter through:

• •gas porosity from melt handling
• •shrinkage porosity in thick bosses
• •oxide folds at flow-front meeting zones
• •insufficient machining allowance at sealing faces
• •thread or port machining breaking into porosity
• •coating or impregnation assumptions not stated in the RFQ

This is why leak-test requirements should be paired with process review. A supplier should look at wall thickness, gating, feeding, machining datums, and seal-face geometry before final quotation. For broader RFQ packaging, see casting plus CNC RFQ checklist for housings.

What to attach to the RFQ

Attach these files when possible:

• •2D drawing with revision status
• •3D STEP model
• •port and thread details
• •sealing-face surface finish requirement
• •assembly drawing or interface sketch
• •operating pressure and temperature
• •leak-test specification if one exists
• •inspection report template if required

If a buyer cannot share the full assembly, a simplified interface sketch is still useful. The supplier needs to understand which faces seal, which ports connect, and which features are machined after casting.

Supplier questions buyers should ask

Use these to separate capable suppliers from quote-only suppliers:

• •Which casting process are you recommending for this housing and why?
• •Where do you see the highest leak-risk zones in the current geometry?
• •Will leak testing be done before machining, after machining, or both?
• •What test medium and pressure are assumed in your quote?
• •Is the leak-test fixture included in tooling cost or quoted separately?
• •What records will be provided with samples and pilot batches?
• •How will nonconforming parts be segregated and traced?
• •What design changes would reduce leak risk before tooling?

If the supplier cannot answer these before tooling, the RFQ is not yet ready for award.

Bohua RFQ path for pump housings

For pump housing RFQs, Bohua reviews casting route, alloy, machining datums, sealing faces, and leak-test requirements together. The quote should make clear which assumptions are included and which need buyer confirmation. Start with the pump housing RFQ path, or send files through the request-quote form.

FAQ

Should leak testing happen before or after machining?

It depends on the risk. Pre-machining testing can detect major through-porosity early. Post-machining testing is often more relevant because machining opens ports, bores, and sealing faces where leaks may appear. Some programs use both during validation, then reduce to the agreed production plan.

Is helium testing always better than air testing?

No. Helium is more sensitive, but it is not always necessary for production screening. The correct method depends on the leak-rate threshold, part function, fixture design, and cost target.

Should leak-test fixtures be part of tooling cost?

They should be identified clearly either way. For complex housings, leak-test fixtures can be a meaningful cost item. If one supplier includes the fixture and another excludes it, the quotes are not comparable.

What if my drawing only says "leak test required"?

Treat it as incomplete. Add a temporary RFQ note asking the supplier to propose test method, pressure, duration, acceptance threshold, and fixture assumptions, then freeze the requirement before tooling release.