What is PPAP? A Complete Guide for CNC Machined Parts Buyers
Written by the engineering team at Robocon CNC Pvt Ltd, Pune, India. We provide PPAP Level 1–3 documentation for US and European OEM customers.
PPAP — Production Part Approval Process — is a quality documentation framework originally developed by the Automotive Industry Action Group (AIAG) for automotive supply chains. Today it is widely used across aerospace, medical devices, industrial automation, and any manufacturing application where a buyer needs confidence that a supplier's production process will consistently deliver parts to drawing.
If you are sourcing CNC machined parts from India for the first time, understanding PPAP levels helps you ask the right question at quote stage — and avoid paying for documentation you don't need.
The Five PPAP Levels
| Level | What the Supplier Submits | Typical Use Case |
|---|---|---|
| Level 1 | Part Submission Warrant (PSW) only | Low-risk, non-critical parts; existing supplier relationship |
| Level 2 | PSW + selected supporting documents | Moderate criticality; new supplier for standard parts |
| Level 3 | PSW + complete supporting package retained at supplier | Safety-critical or complex parts; most common level requested |
| Level 4 | PSW + other requirements as defined by customer | Customer specifies exact documents required |
| Level 5 | Full PPAP package retained at supplier + reviewed on-site by customer | Highest-criticality parts; customer audits supplier |
What is in a Full PPAP Package (Level 3)?
A Level 3 PPAP for a CNC machined part typically includes:
- Design Records — Customer drawing, revision level, and any engineering change records
- Engineering Change Documents — If any changes were made post-drawing release
- Customer Engineering Approval — Sign-off from customer engineering team
- FMEA (Failure Mode and Effects Analysis) — Process FMEA identifying potential failures
- Process Flow Diagram — Material receipt → machining → inspection → shipping
- Control Plan — What is checked, how, and at what frequency
- Measurement System Analysis (MSA) — Gauge R&R studies for critical measurement equipment
- Dimensional Verification Results — CMM or manual inspection data for all ballooned dimensions from FAI sample
- Material, Performance, and Process Test Results — Material certificates, hardness test, surface finish records
- Qualified Laboratory Documentation — Lab accreditation if external testing is used
- Appearance Approval Report — For cosmetically critical parts
- Sample Parts — Physical samples submitted to customer if required
- Master Sample — A reference sample retained at supplier
- Checking Aids — Fixtures, gauges, or jigs used to verify part
- Records of Customer-Specific Requirements
- Part Submission Warrant (PSW) — The summary document signed by supplier and approved by customer
What Level Should You Request for CNC Machined Parts?
- Prototype / pre-production parts: FAI (First Article Inspection) report only — no formal PPAP required. This is a dimensional inspection report covering all balloon dimensions on the drawing.
- Standard production parts (non-critical): Level 1 or Level 2. A PSW plus material cert and CMM report is usually sufficient.
- Safety-critical or OEM production parts: Level 3. Most US and European OEMs request Level 3 for first production runs with a new supplier.
- Automotive IATF 16949 suppliers: Level 3 minimum, typically with full FMEA and Control Plan.
How Robocon CNC Handles PPAP
We provide PPAP Level 1 through Level 3 documentation for export customers. Our standard documentation package includes:
- CMM dimensional report (all ballooned dimensions from drawing)
- EN 10204 3.1 material test certificate
- Surface finish measurement records (where specified)
- Part Submission Warrant (signed by our quality team)
- Process Flow Diagram and Control Plan (Level 3)
PPAP documentation is prepared for the first production run. Subsequent repeat orders under the same drawing revision ship with a material cert and CoC unless the customer requests re-PPAP.
Specify your PPAP level requirement at quote stage — not after order placement. It affects lead time (Level 3 adds 2–3 days to prepare the full package) and pricing. If you are unsure which level you need, ask your customer quality team before sending the RFQ.