Quick Answer
A casting company is qualified by evidence, not by its website. The nine checks that predict a good supplier: process fit for your part, alloy competence with certificates, in-house inspection, real DFM feedback before quoting, machining under the same roof, heat-treatment control, a working quality system, honest capacity answers, and communication that survives technical questions. Price ranks tenth — because every problem above turns a cheap quote into an expensive part.
The Nine Checks
- 1. Process fit. Does the foundry actually run the process your part wants — investment, sand, gravity, low-pressure — or will they subcontract it? Ask which processes run in-house and at what size range.
- 2. Alloy competence. A shop pouring CF8M weekly is a different risk from one that “can source it”. Ask for recent material certificates in your grade family.
- 3. Inspection you can audit. Spectrometer, tensile testing, hardness, MPI/DPT at minimum; CMM if machined dimensions matter. “We can send it out for testing” means added weeks per issue.
- 4. DFM feedback quality. Send the drawing and watch what comes back. A serious foundry queries radii, wall transitions, datum schemes and tolerance over-specification before quoting. A price with no questions is a warning, not a convenience.
- 5. Machining under the same roof. Cast-plus-machine from one supplier removes the classic blame loop between foundry and machine shop when a datum disagrees.
- 6. Heat treatment control. Own furnaces with charted cycles, or a documented subcontract chain. Ask how hardness is verified per lot.
- 7. Quality system in daily use. ISO 9001 is a floor. Better evidence: first-article reports, control plans, and how nonconformances were handled last quarter.
- 8. Honest capacity and lead time. A supplier who says “six weeks, furnace is full” is more valuable than one who promises three and delivers in eight.
- 9. Communication under load. Technical questions answered by engineers within a day or two — in the language your team works in — predicts how problems will be handled after the PO.
Red Flags Worth Walking Away From
- Quotes returned within hours on a complex drawing, unquestioned
- No material certificates, or reluctance to commit to per-heat chemistry
- “Any alloy, any size, any process” positioning with no visible specialization
- Samples that arrive without dimensional reports
- Prices far below the field — the gap reappears later as rework, delay or substitution
A Fast Qualification Sequence That Works
- Step 1: Send one representative drawing plus the environment/load context. Score the questions that come back.
- Step 2: Order samples with a first-article inspection report — what belongs in it is covered in our first piece approval vs FAI guide.
- Step 3: Pilot batch with agreed inspection level, then scale. Track supplier performance from day one — the KPI set is in our supplier scorecard guide.
What This Looks Like in Practice
For calibration: YCUMETAL runs silica sol investment casting, coated sand casting and CNC machining in one Qingdao plant, pours stainless, carbon and low-alloy steels plus aluminum alloys, and answers drawings with DFM notes before a price. Judge any supplier — including us — against the nine checks above; the factory profile is where to start.
FAQ
Should I qualify two casting suppliers or one?
For production parts with real volume: two, with tooling strategy agreed up front. For low-volume or tooling-heavy parts, one deep relationship usually wins.
How many samples are normal before production?
Three to ten pieces with a full FAI on one or two of them, depending on complexity and your industry’s PPAP habits.
Is a trading company ever acceptable?
It can be for simple parts — but you lose direct DFM contact and root-cause access when a defect appears. For engineered castings, work with the factory.