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For automotive buyers, a die cast part is not ready for production until its PPAP is approved. For suppliers, PPAP is where the promises made at quotation become evidence. Understanding what each element means for a casting, not for a generic part, makes the process faster for both sides.
PPAP has 18 elements and five submission levels, with Level 3 as the default. For die castings, the elements that need the most care are dimensional results for every cavity, material results (chemistry and porosity), process capability on critical features, and a PFMEA and control plan that reflect real casting risks.
What PPAP is for
The Production Part Approval Process is defined by the Automotive Industry Action Group (AIAG) and used across the automotive supply chain. It answers two questions before production starts: does the supplier understand every requirement on the drawing and specification, and can their production process meet those requirements consistently at the quoted rate?
The key word is production. PPAP parts must come from the production die, production machine, production operators and production gauges, not from a prototype route.
The 18 PPAP elements, applied to a die casting
| # | Element | What it looks like for a die cast part |
|---|---|---|
| 1 | Design records | The released drawing and 3D model at the correct revision, ballooned for inspection |
| 2 | Engineering change documents | Any approved changes not yet on the drawing, such as added draft or radii agreed at DFM |
| 3 | Customer engineering approval | Approval from the customer's engineering team, when required |
| 4 | Design FMEA | Owned by the design-responsible party, usually the customer for build-to-print castings |
| 5 | Process flow diagram | Melting, degassing, casting, trimming, fettling, machining, finishing, inspection, packing |
| 6 | Process FMEA | Casting risks such as porosity, cold shuts, soldering, flash and dimensional drift |
| 7 | Control plan | What is checked at each step, how often, with which gauge, and the reaction plan |
| 8 | Measurement system analysis | Gauge R&R studies on the gauges used for critical features |
| 9 | Dimensional results | Full layout against every drawing dimension, for each cavity |
| 10 | Material and performance test results | Alloy chemistry by spectrometer, porosity results, leak test, mechanical properties if specified |
| 11 | Initial process studies | Capability studies (Ppk) on critical features from the significant production run |
| 12 | Qualified laboratory documentation | Scope and accreditation of labs used, in-house or external |
| 13 | Appearance approval report | Only for parts with appearance requirements, such as visible coated covers |
| 14 | Sample production parts | Parts from the significant production run, identified by cavity |
| 15 | Master sample | A retained, approved sample used as a reference |
| 16 | Checking aids | Fixtures and special gauges used to inspect the part |
| 17 | Customer-specific requirements | Anything the customer adds, such as specific test reports or labelling |
| 18 | Part Submission Warrant | The summary document signed by the supplier, declaring the submission complete |
The five submission levels
- Level 1: Part Submission Warrant only (plus appearance approval if applicable).
- Level 2: warrant with product samples and limited supporting data.
- Level 3: warrant with product samples and complete supporting data. This is the default.
- Level 4: warrant and other requirements as defined by the customer.
- Level 5: warrant with samples and complete supporting data, reviewed at the supplier's manufacturing location.
Whatever the level, the supplier keeps the complete PPAP file. The level only decides how much is submitted to the customer.
What is different about castings
Every cavity counts
A two-cavity die is effectively two processes. Dimensional results are needed for each cavity, and parts should stay identified by cavity number through sampling, so a problem can be traced to the right insert.
Agree porosity criteria before tooling
Porosity is the most common source of argument in casting approvals, because "no porosity" is not achievable or measurable. Agree up front which zones matter, how they are checked (X-ray, sectioning or leak testing) and what is acceptable, for example by reference to radiographic standards or a maximum pore size in machined sealing faces. Our article on porosity in aluminium castings explains the causes and controls.
Chemistry is per melt, not per part
Material results for castings usually mean spectrometer analysis of the alloy, recorded per melt or batch and reported on the material test certificate. If mechanical properties are specified, agree whether they come from separately cast test bars or from specimens cut from the part, because results differ.
Machined castings need datums that match
When a supplier both casts and machines, dimensional results cover the as-cast and machined features. The datum scheme on the drawing should be the same one used for fixturing; otherwise capability on machined features can look worse than the process really is.
AIAG calls for a run of one to eight hours of production, totalling at least 300 consecutive parts unless the customer specifies otherwise. Plan this run as normal production at the normal rate, not as a carefully nursed trial, because that is what the approval is based on.
Why PPAP submissions get rejected
- Revision mismatch: the drawing revision on the warrant, ballooned drawing and dimensional report do not agree.
- Missing cavities: results submitted for one cavity of a multi-cavity die.
- Capability without a capable gauge: Ppk studies on features whose measurement system has not passed MSA.
- A generic PFMEA: a template that does not mention the real risks of this casting.
- Undefined acceptance criteria for porosity, leak rate or appearance.
If you are not in automotive
Full PPAP is designed for automotive programmes. Other industries often use lighter approvals that cover the same ground:
- First article inspection (FAI): a full dimensional report on the first parts from the production tool. Aerospace buyers may specify AS9102 format.
- ISIR: the Initial Sample Inspection Report used by many European customers, often to VDA Volume 2.
- Material test certificate and control plan, which give ongoing assurance once production starts.
Asking for the approval you will actually use keeps the cost and lead time of sampling down. Our RFQ checklist covers how to specify it.
How we handle PPAP at Alcast
We work to APQP from the first DFM review, so the process flow, PFMEA and control plan are developed alongside the die rather than written after it. Every alloy batch is checked by spectrometer, porosity is controlled with a rotary degasser and density index testing, and X-ray is available in-house. All dimensional measurement is done at the 20 °C (68 °F) reference temperature. CMM inspection and leak testing are arranged through specialist partners when a programme needs them. Our quality system is ISO 9001 certified, with IATF 16949 targeted for March 2027. See our quality page for details.
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The people who run melting, casting, machining and inspection across our four units in Satara, Maharashtra, making aluminium die castings since 2009. Ask us a question.
