Automotive Gravity Casting RFQ Guide

# Automotive Gravity Casting RFQ Guide

Automotive aluminum castings are rarely judged by casting shape alone. Buyers also need to know whether the supplier can manage alloy selection, heat treatment, machining datums, leak or pressure risk, inspection records, and export communication after the tool is launched.

This guide is for procurement teams, SQE teams, engineers, and sourcing managers preparing RFQs for automotive gravity cast parts such as intake manifolds, suspension brackets, housings, covers, pump-related components, EV motor housings, and structural brackets. It explains where gravity casting may fit, what to compare against die casting or low-pressure casting, and what evidence to ask for before sharing production drawings.

Use it as an RFQ preparation checklist, not as a universal process rule. The best route still depends on drawing geometry, alloy, wall thickness, annual volume, machining scope, inspection level, and customer approval requirements.

When Automotive Buyers Consider Gravity Casting

Gravity casting, also called permanent mold casting or gravity die casting, pours molten aluminum into a reusable metal mold without high-pressure injection. For automotive RFQs, it is often considered when the part needs a balance of structural integrity, machining stability, and realistic tooling cost.

Common situations include:

• •The part has medium to thick wall sections that are not ideal for thin-wall high-pressure die casting.
• •The buyer needs A356, ZL114, or another heat-treatable aluminum alloy route.
• •Machined faces, bearing seats, mounting bosses, or sealing areas drive the final part function.
• •The drawing includes ribs, bosses, brackets, passages, or inserts that need early DFM review.
• •The RFQ requires inspection records such as CMM, material certificates, heat-treatment records, leak-test records, FAI, or PPAP-style documentation.
• •The program volume is not high enough to justify the highest-pressure tooling route without checking total cost and launch risk.

If the part is very thin, very high volume, and designed around ADC12 or A380-style die casting, die casting may still be the better route. If filling control or leak risk dominates the design, low-pressure casting should also be compared. Start with gravity casting only when the drawing supports the process.

Automotive RFQ Inputs That Matter

A useful automotive casting RFQ should make the supplier quote the same scope that the buyer actually needs. Send as many of these inputs as possible:

For drawing-ready projects, use the structured request quote route so the RFQ context travels with the inquiry.

Choose the right automotive gravity casting route

Different automotive buyers use this page for different part families. Route the RFQ to the page that matches the drawing risk instead of sending every buyer to a generic contact form.

If the part family is unclear, start with the automotive industry route and then submit the drawing package through request quote.

Process Fit: Gravity Casting vs Die Casting vs Low-Pressure Casting

Automotive buyers usually compare more than one process. The right comparison should start from the drawing, not from a supplier's favorite process.

Gravity casting may fit when

• •The part has thicker walls, heavier bosses, or variable sections.
• •Heat-treatable A356 or ZL114 is being considered.
• •Machining datums, gasket faces, or bearing seats control final function.
• •Medium-volume tooling economics matter.
• •The buyer needs a supplier to review casting plus CNC machining together.

Die casting may fit when

• •The part is thin-wall, high-volume, and designed for ADC12 or A380-style alloys.
• •Cycle time and high-volume repeatability dominate the sourcing decision.
• •As-cast surface and dimensional repeatability are more important than heat-treatment flexibility.
• •The drawing does not require the same ductility or heat-treatment path as A356-T6.

Low-pressure casting may fit when

• •Controlled filling is important for a pressure-sensitive or leak-sensitive part.
• •The part has fluid passages, sealing surfaces, or housing geometry that needs lower turbulence.
• •The buyer wants to compare filling control against gravity casting before tool design.

For broader process comparison, pair this guide with the casting process selection resource and the aluminum gravity casting design guide.

What To Ask The Supplier Before Shortlisting

The fastest way to separate a real automotive casting supplier from a brochure is to ask questions tied to the drawing.

Ask:

• •Which alloy route do you recommend for this drawing, and why?
• •Which areas are most sensitive to shrinkage, porosity, hot spots, or machining movement?
• •What wall thickness or rib changes would make the part easier to cast consistently?
• •Which surfaces should be cast with machining allowance, and how much allowance do you assume?
• •If T6 or another heat treatment is required, how will you control dimensional movement?
• •What CMM, gauge, leak-test, material, or heat-treatment records can be included with samples?
• •Can you quote raw casting only, casting plus CNC machining, or a finished-part package?
• •What tooling assumptions, sample sequence, and approval records are included in the quote?
• •If this is a second-source project, can you work from the current drawing and existing sample without using customer-restricted information incorrectly?

Good answers should name the risk areas on the part. Weak answers usually stay generic: "high quality," "best price," "fast delivery," or "no problem" without explaining process control.

Automotive Part Families Where The Checklist Helps

This RFQ framework is useful for several automotive and mobility part families:

• •Intake manifolds and air-path components where runner geometry, flange flatness, port machining, sensor bosses, and pressure or vacuum context matter. See the intake manifold quote route.
• •Suspension brackets, shock absorber housings, and structural brackets where A356-T6, datums, CMM records, and PPAP-style evidence may be part of qualification. See the automotive suspension bracket RFQ route.
• •EV motor housings, end covers, and drive-unit housings where bearing bores, sealing faces, thermal interfaces, and machining stability control the quote. See the EV motor housing route.
• •Gearbox housings, reducer housings, and drive cases where bearing seats, gasket faces, T6 movement, concentricity, and inspection records matter. See the gearbox housing route.
• •Pump, hydraulic, and fluid-related automotive parts where leak criteria, sealing faces, port machining, and pressure-test assumptions need to be defined before price comparison.

These examples do not mean gravity casting is automatically correct. They mean the buyer should request a process-fit review before accepting a quote that only lists piece price.

Inspection And Evidence Buyers Should Request

Automotive RFQs often fail because the quote does not define the evidence package. Before comparing suppliers, decide which records are needed for your program stage.

Common evidence includes:

• •First article inspection report with critical dimensions.
• •CMM report for machined datums, bores, mounting faces, or hole patterns.
• •Material certificate or spectrometer record for alloy confirmation.
• •Heat-treatment record when A356-T6, ZL114-T6, or similar conditions are specified.
• •Leak-test or pressure-test record when the part is pressure-sensitive.
• •X-ray, CT, dye penetrant, or other NDT scope if required by the drawing or customer plan.
• •Machining fixture and datum explanation for finished-part supply.
• •Packaging review for machined faces, threads, sealing areas, and export handling.
• •PPAP, FAI, or customer-specific approval records when requested.

Do not assume every project needs the same documentation. A prototype bracket, a pilot intake manifold, and a serial housing may need different evidence packages.

How To Compare Supplier Quotes

For automotive gravity casting, the lowest quoted piece price is not always the best comparison. A useful comparison separates included and excluded scope.

Check whether each quote includes:

• •Tooling design, tool ownership, and tool maintenance assumptions.
• •Sample casting, machining, and inspection scope.
• •Heat treatment, surface finish, coating, or cleaning.
• •CNC machining, threads, inserts, leak testing, or pressure testing.
• •CMM, FAI, PPAP, material records, and heat-treatment reports.
• •Packaging for export and protection of machined surfaces.
• •Incoterms, freight assumptions, duties, and payment terms.
• •Engineering communication for DFM changes and drawing revisions.

If one supplier quotes only raw casting and another quotes finished casting plus CNC plus inspection records, the lower number may not represent the same delivered value.

Bohua Fit For Automotive Gravity Casting RFQs

Bohua is a fit when the buyer needs a China aluminum casting supplier that can review gravity casting, machining, inspection, and export quote assumptions together. The strongest fit is usually a drawing-based RFQ where the buyer can share geometry, annual volume, alloy expectation, machining scope, and inspection needs.

Relevant routes:

• •Automotive industry RFQ context
• •Gravity casting process route
• •A356 material route
• •Automotive suspension bracket RFQ
• •Intake manifold OEM quote
• •EV motor housing manufacturer route

If your team is sourcing automotive aluminum castings, send the drawing package, alloy target, annual demand, machining scope, inspection requirements, and approval expectations through the request quote form. Bohua can review the RFQ assumptions and prepare a structured quote for the applicable manufacturing route.

FAQ

Is gravity casting always better than die casting for automotive components?

No. Gravity casting may be a strong option for some heat-treatable, machined, medium-volume, or thicker-section parts. Die casting can be better for thin-wall, high-volume, ADC12 or A380-style components. The drawing should decide the process.

What information should I send for an automotive casting quote?

Send the 2D drawing, 3D model, alloy requirement, annual volume, machining scope, inspection requirements, heat-treatment requirement, leak or pressure criteria, surface finish, and whether PPAP or FAI records are expected.

Can Bohua quote casting plus CNC machining?

Yes, when the drawing defines the machining scope. Buyers should mark datum surfaces, sealing faces, threads, bores, hole patterns, flatness, and CMM or gauge requirements so the quote includes the right finished-part assumptions.

Should I request PPAP for every automotive casting RFQ?

Not always. PPAP or customer-specific approval records should match the program stage and customer requirement. If PPAP is expected, define the level, documents, sample quantity, and timing in the RFQ.

How should I compare China automotive casting suppliers?

Compare process fit, drawing review quality, tooling assumptions, machining capability, inspection records, communication, export packaging, and quote inclusions. Avoid comparing only the raw casting price unless all suppliers are quoting the same scope.