The Elements That Matter for Turned Parts
PPAP has 18 elements, but a turned-parts supplier spends most effort on a handful. Design records and engineering change documents, process flow diagram, PFMEA, control plan, measurement system analysis, dimensional results, material and performance test results, initial process studies, qualified laboratory documentation, appearance approval if relevant, sample parts, and the Part Submission Warrant. Customers specify which elements and what level.
Level 1 is warrant only; level 3, the common default, is the warrant plus samples and complete supporting data. Confirm requirements in writing before you start, including any customer-specific requirements layered on top of the AIAG manual.
- Ballooned drawing tied to dimensional results for every characteristic
- Process flow, PFMEA and control plan that agree with each other
- Gauge R&R on gages used for critical and special characteristics
- Initial process capability on designated characteristics
- Material certifications and any required test reports, such as plating or heat treat
Capability Studies on Turned Features
33 for ongoing capability. Turned parts often meet these on diameters and lengths when the process is stable, and struggle on features like runout, concentricity, thread pitch diameter and surface finish. Tool wear, thermal drift in the first hours of a run and bar variation all show up here.
Sample across multiple bars and tool changes, since a study taken from one lucky stretch will not reflect production and will not survive the first complaint.
Gauge R&R, Controls and Calibration
Measurement system analysis is where many submissions bounce. 0005 inch tolerance with the wrong gage will show poor Cpk caused by measurement noise. Plan gages early: air gages, thread gages, optical comparators, vision systems and CMMs each have a place.
Document calibration status and traceability for every gage listed in the control plan, and make sure the control plan frequencies are ones the floor can actually execute. A control plan that demands hourly checks nobody performs is a finding waiting to happen.
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PPAP 18 Elements Supplier Submission Reference
A reference of the 18 PPAP elements, what each proves, what evidence to expect and what a reviewer should check.
Keeping PPAP Documents Consistent
The most common PPAP rejection is not a bad process but inconsistent paperwork: a drawing revision that does not match the control plan, a characteristic missing from the flow diagram, a PSW signed against an old revision. Keep a single part record with drawing revision, characteristics, gage assignments, capability results and approval dates. Whether that lives in your ERP, a QMS, or a controlled folder structure, the key is that revisions propagate.
After approval, retain the package, because the customer may ask for re-submission on any change in process, tooling location, material source or sub-supplier.
Where AI Helps with PPAP Paperwork
AI can read a customer drawing and draft the ballooned characteristic list, cross-check that every characteristic appears in the control plan and dimensional results, and flag revision mismatches across documents. It can also pull inspection data from your system to assemble the dimensional results table for human review. It does not decide capability or sign off anything, and a quality manager owns the submission.
If you submit only a few PPAPs a year, a good checklist and template set is enough; AI pays off when you handle dozens of part submissions across several customers.
Frequently asked questions
What does PPAP require for a turned part?
Typically a Part Submission Warrant, ballooned drawing, dimensional results, process flow, PFMEA, control plan, MSA studies, initial capability studies and material certifications, with sample parts. Exact elements depend on the customer's requested submission level, commonly level 3.
What Cpk is required for PPAP?
Customers set it, but 1.67 is a frequent target for initial studies on critical characteristics and 1.33 for ongoing capability. Always confirm the requirement and the sample size, often 30 consecutive pieces or more, in writing.
Do I need PPAP if I am not IATF 16949 certified?
Many customers still require PPAP from non-certified suppliers because the requirement flows down from their own certification. Certification and PPAP are separate: PPAP is a customer submission, while IATF 16949 is a quality system standard your customer may or may not require.
Netray can run a private AI check that your drawing, control plan and dimensional results agree before you submit, on documents that never leave your network.