OEM SKF-Spec Bearing PPAP Level Definitions for Buyers

PPAP Level 1 through Level 5 is not a ladder of quality; it is a ladder of evidence depth.

PPAP Level 1 requires only the Part Submission Warrant (PSW); Level 2 adds samples and limited supporting data; Level 3—the industry default—demands the full eighteen-element package; Level 4 is customer-defined; and Level 5 requires all documentation plus a full on-site audit at the supplier’s facility.

I still remember the morning I opened an email from a Mexican automotive tier-one buyer, cold-sweating because my PSW had been rejected twice. The issue was not the data inside—it was the signature block. I had stamped the company chop, assuming it carried authority. The buyer’s supplier quality engineer later explained that the OEM’s approved quality representative signature is mandatory, and a company seal means nothing on a PSW [NEED_CITE: PSW signature authority rules per AIAG PPAP 4th Edition]. That two-week delay cost us the program. Since then, I have walked through PPAP submissions for bearing orders across automotive, industrial motor, and agricultural equipment lines, and the single most repeated mistake I see among buyers is treating "higher level = better." It is not. Choosing the wrong PPAP level wastes your supplier’s time, exposes unnecessary process details, and can delay your line launch.

Let me walk you through what each level actually means for a bearing buyer, what gets submitted, what can be waived, and where most submissions fail.

What Exactly Does PPAP Level 1–5 Mean for Bearings?

The Level number defines how much proof the OEM asks to see, not how good the bearing is.

A deep groove ball bearing such as a 6205 produced in a certified facility meets the same dimensional and material specifications regardless of whether it ships under a Level 1 or Level 5 PPAP. The difference lies entirely in what the supplier must show the customer before mass production is approved.

Level 1 is the lightest touch: the supplier submits only the PSW. This is typically used for standard catalog bearings with no design changes, long-running production history, or low-risk applications such as general-purpose fan motors [NEED_CITE: PPAP submission level selection criteria per AIAG PPAP 4th Edition].

Level 2 adds product samples and limited supporting data—usually dimensional reports and material test certificates. A European industrial motor OEM I worked with once asked for Level 2 on a repeat order of 22320 spherical roller bearings after a minor packaging change. They wanted to confirm the bearing itself was untouched.

Level 3 is the default for most new part numbers. It requires the complete set of supporting documents: design records, process flow diagrams, control plans, MSA studies, initial process capability studies, and dimensional and material test results. This is the level most automotive OEMs specify for first-article approval of tapered roller bearings such as 32218 or 30206 used in wheel hubs and gearboxes.

Level 4 is fully customer-defined. The OEM picks and chooses which elements to submit. I have seen this used when a buyer wants the control plan and MSA but does not need the full DFMEA package because the bearing design is mature and standardized.

Level 5 requires everything in Level 3 plus a full on-site review at the supplier’s manufacturing location. This is reserved for safety-critical or high-consequence applications—steering column bearings, mining conveyor idler bearings, or any component where field failure carries serious liability [NEED_CITE: PPAP Level 5 on-site audit requirements per IATF 16949].

A common misconception is that Level 5 is always the safest choice. In reality, most OEMs do not need it. Sending a full audit team to a bearing factory for a standard 6305 order adds cost and time without adding measurable quality value.

Which Documents Are Required at Each Level?

The eighteen PPAP elements are fixed; what changes by level is how many of them you actually hand over.

Under AIAG PPAP 4th Edition, the full element list includes: design records, authorized engineering change documents, customer engineering approval, DFMEA, process flow diagrams, PFMEA, control plan, MSA studies, dimensional results, material and performance test results, initial process studies, qualified laboratory documentation, appearance approval report, sample production parts, master sample, checking aids, customer-specific requirements, and the PSW [NEED_CITE: complete PPAP 18-element list per AIAG PPAP 4th Edition].

At Level 1, only the PSW is submitted. If the bearing has specific appearance requirements—an unusual case for standard industrial bearings but possible for certain branded housings—an Appearance Approval Report may also be required.

At Level 2, the supplier submits the PSW plus samples and limited supporting data. In practice, this usually means dimensional inspection reports, material certificates, and the PSW itself. Process-level documents such as the control plan and PFMEA are retained at the supplier’s site but not sent.

At Level 3, everything goes. The full eighteen-element package is submitted to the customer. For a bearing order, this typically includes the design record (drawing or cross-reference confirmation), process flow from forging through grinding and assembly, the control plan covering each critical operation, MSA results for the gauges used in final inspection, and initial process capability data (Ppk values) for critical dimensions such as bore diameter, outside diameter, and width.

At Level 4, the customer specifies exactly which elements are required. This is common when a buyer has an established relationship with the bearing supplier and only needs confirmation of specific changes.

At Level 5, all Level 3 documents are prepared and retained at the supplier’s facility, available for on-site review by the customer’s quality team.

Our factory runs to ISO 9001 standards and keeps the full Level 1–3 documentation package on file for regular orders—PSW, control plans, inspection reports, material certificates, and process flow charts. When an OEM buyer provides their supplier quality manual, we map our standard documentation directly to their required level without re-preparing from scratch.

What Can Be Waived and Why?

Not every element must be submitted every time; waiver logic is built into the standard.

The AIAG PPAP manual allows customers to waive specific elements based on product risk, supplier performance history, and process maturity [NEED_CITE: PPAP element waiver criteria per AIAG PPAP 4th Edition]. This is not a loophole—it is a rational allocation of quality resources.

For a standard deep groove ball bearing such as a 6206 with no design changes and a long production history, the DFMEA and PFMEA may be waived if the customer accepts the supplier’s documented process stability. The rationale is straightforward: if the process has run for years without deviation, re-submitting the same failure mode analysis adds no new information.

Initial process studies (Ppk data) can also be waived for stable, high-volume bearing production lines where ongoing SPC data already demonstrates capability. A Latin American agricultural equipment distributor I supplied once received a waiver on initial process studies for a repeat order of NU205 cylindrical roller bearings because the customer’s own incoming inspection data over multiple batches confirmed consistent quality.

Appearance Approval Reports are almost never required for standard industrial bearings unless the customer has specific cosmetic specifications—such as for branded bearing shields or custom-painted housings.

Material test certificates, however, are almost never waived. Bearing steel chemistry and hardness are fundamental to performance, and no OEM will accept a bearing shipment without verifiable material traceability.

The key is to confirm waiver eligibility with the customer’s SQE before preparing the submission. Assuming a waiver without written confirmation is one of the most common reasons for PPAP rejection.

Common Mistakes That Cause PPAP Rejection?

Signature errors, document version mismatches, and missing MSA data are the three most frequent rejection triggers.

I have seen PPAP submissions rejected for reasons that had nothing to do with the bearing quality itself. The product was fine; the paperwork was not.

The first and most common mistake is PSW signature authority. The PSW must be signed by a person explicitly authorized by the supplier’s quality management system—and the customer often requires that the signatory be identifiable and verifiable. A company chop or an unauthorized signature will be rejected outright. I learned this the hard way with that Mexican automotive customer. The fix is simple: maintain a current list of authorized signatories and ensure the PSW signer is on it.

The second mistake is document version inconsistency. The control plan references a process step that does not match the current process flow diagram. The PFMEA cites a different detection method than the one in the control plan. These mismatches signal to the SQE that the documentation was not reviewed as a coherent package. For bearing production, this often happens when a grinding process is updated but the control plan is not revised to match.

The third mistake is missing or incomplete MSA data. The customer requests gauge R&R results for the instruments used to measure critical bearing dimensions, and the supplier either provides none or provides data from the wrong gauge. This is particularly common when a supplier uses multiple inspection stations and submits MSA from one station while the dimensional report comes from another [NEED_CITE: MSA gauge R&R requirements per AIAG MSA 4th Edition].

Other recurring issues include: dimensional reports that do not reference the correct drawing revision, material certificates that lack heat number traceability, and process capability studies that use the wrong specification limits.

How to Prepare PPAP Without Over-Submitting?

Start with the customer’s Supplier Quality Manual, then build only what is required.

Over-submitting is not just wasteful—it can be counterproductive. Sending the full PFMEA and detailed process flow diagrams to a customer who only asked for Level 2 exposes proprietary manufacturing methods unnecessarily. For bearing suppliers, this can include specific grinding parameters, heat treatment profiles, or assembly sequences that represent competitive know-how.

The correct approach is to first obtain and review the customer’s Supplier Quality Manual or specific PPAP instructions. Most OEMs and tier-one buyers publish these documents, and they specify exactly which level is required and which elements are mandatory. If the manual is unclear, confirm in writing with the SQE before preparing the submission.

Next, assemble the documentation package to match the required level exactly. For a Level 3 submission on a standard bearing order, this means preparing the PSW, design records or cross-reference confirmation, process flow diagram, control plan, MSA results, dimensional and material test reports, and initial process studies. Do not include the DFMEA or PFMEA unless specifically requested, unless the customer’s manual makes them mandatory.

Ensure all documents reference the same drawing revision and part number. Cross-check the control plan against the process flow diagram line by line. Verify that MSA data corresponds to the gauges actually used for the dimensional report.

Finally, submit the package through the customer’s designated portal or contact, and retain a complete copy at your facility. If the customer later requests additional elements or an on-site review, you should be able to provide them without starting from scratch.

Conclusion

PPAP level selection is a risk-based decision, not a quality ranking.

Level 1 through Level 5 defines the depth of evidence a bearing supplier must provide, not the quality of the product itself. Understanding the submission requirements, waiver logic, and common rejection triggers allows buyers to request the right level of documentation—avoiding both under-submission that delays approval and over-submission that exposes unnecessary process details. Confirm requirements with the customer’s SQE, prepare documents as a coherent package, and ensure signature authority is current.