PPAP for Die Casting -A Buyer's Complete Guide

PPAP (Production Part Approval Process) is the automotive industry's formal gate between development and production. It answers four questions simultaneously that no other quality document addresses:

1. Is this the right part? (Design documentation, dimensional results)
2. Was it made the right way? (Process flow, PFMEA, control plan)
3. Can it be made consistently? (Process capability, Cpk)
4. Can it be measured reliably? (MSA / Gage R&R)

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PPAP Levels

Level	What Is Submitted	Typical Use
1	Part Submission Warrant (PSW) only	Low-risk commodity parts
2	PSW + limited supporting data	Standard commercial parts
3	PSW + complete supporting data	Standard for new automotive programs
4	Customer-defined requirements	Customer-specified
5	Complete data reviewed at supplier site	Safety-critical, new technology

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Level 3 PPAP -All 18 Elements

Element	Content	KastMfg Deliverable
1. Design documentation	Drawing + revision	Customer-supplied
2. Engineering changes	ECR/ECN authorizations	If applicable
3. Engineering approval	Customer sign-off	Customer action
4. DFMEA	Design FMEA	Customer-supplied or KastMfg (design responsibility)
5. Process flow diagram	Raw material through shipping	KastMfg
6. PFMEA	Process failure mode analysis	KastMfg
7. Control plan	All process controls and inspection	KastMfg
8. MSA (Gage R&R)	Measurement system studies	KastMfg
9. Dimensional results	100-piece measurement layout	KastMfg
10. Material certificates	OES chemistry per melt	KastMfg
11. Performance test results	Pressure test, X-ray, mechanical	KastMfg
12. Initial process capability	Cpk on all Special Characteristics	KastMfg
13. Lab documentation	Calibration certificates for gauges	KastMfg
14. Appearance approval	AAR form (if appearance requirement)	Joint
15. Sample production parts	3- parts from production run	KastMfg
16. Master sample	Signed reference part, retained	KastMfg retains
17. Checking aids	Gauges and fixtures for inspection	KastMfg retains
18. Customer-specific requirements	VDA, GM, Ford CSRs	As applicable
PSW	Part Submission Warrant -cover sheet	KastMfg-signed

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Cpk >=1.67 -What This Means for Die Casting

Initial process capability (element 12) requires Cpk >=1.67 on all Special Characteristics (safety or functional critical). This means the process mean must be at least 5 sigma from the nearest specification limit.

For a bearing bore with specification ±0.015 mm:

• Cpk = 1.67 means the process standard deviation must be >=.003 mm -and the mean must be centered within ±0.010 mm of nominal
• This is achievable with in-house CNC boring and consistent datum setup
• It is not achievable with as-cast dimensions or inconsistent fixturing

KastMfg runs a minimum 30-piece capability study before PPAP submission, confirming Cpk before submitting the PSW.

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Common PPAP Failures and Prevention

Failure	Root Cause	KastMfg Prevention
Cpk <1.67	Process not capable before PPAP run	SPC run and reviewed before PPAP; parameters locked at capable set
Missing Gage R&R	MSA planned too late	MSA plan established at program launch
PFMEA not reflecting actual process	Template PFMEA, not updated	PFMEA reviewed with production team before submission
Dimensional non-conformance in 100-piece layout	Part design changed after trial approval	FAI performed at same parameter set as PPAP run

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Questions to Ask Your Die Casting Supplier About PPAP

1. Have you submitted Level 3 PPAP to an automotive Tier 1 customer before? (Ask for a redacted example.)
2. What is your standard Cpk target before PPAP submission? (Answer should be >1.67.)
3. Who performs your Gage R&R studies -internal QE or third party?
4. How long does your PPAP preparation take after FAI approval? (Realistic: 2- weeks.)
5. What PPAP resubmission process do you follow if customer requires changes?

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PPAP submission support: yaoqingpu1983@gmail.com | +86 138 1403 4409