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PPAP Explained for Component Buyers: What a Supplier Should Submit
PPAP Explained for Component Buyers
PPAP (Production Part Approval Process) is the documented evidence a supplier gives a customer to prove it can make a part to specification, consistently, at production speed. It is a core requirement across the automotive supply chain and is defined by the AIAG (Automotive Industry Action Group). A PPAP package ends with a signed Part Submission Warrant (PSW) that says the parts meet every requirement.
If you buy automotive components, understanding PPAP helps you ask suppliers the right questions and recognise a well-run quality system. For the certification standard behind it, see what IATF 16949 means for suppliers.
Why PPAP Exists
A sample that passes inspection once proves little. The buyer needs to know that the supplier’s process can repeat that result on every piece, in every batch. PPAP provides that proof before volume production starts, so problems are found while they are still cheap to fix.
It also creates a clear record. If a problem arises later, both sides can compare current production against what was approved.
When Is a PPAP Required?
A PPAP is typically submitted:
- For a new part before production starts
- After an engineering change to the part or drawing
- After a change in material, supplier, or sub-supplier
- After a change in tooling, including repair, refurbishment or relocation
- After a change in the production process or location
- After production has been stopped for an extended period, depending on customer rules
Customers set their own triggers, so always check the customer-specific requirements.
The 18 PPAP Elements
| Factor | Cold Forging | Hot Forging |
|---|---|---|
| Strength | High (strain hardened) | Moderate (ductile) |
| Accuracy | Excellent | Moderate |
| Surface Finish | Smooth, scale-free | Requires finishing |
| Cost per Part | Low (high-volume) | Higher (extra processing) |
| Production Volume | High-volume | Low to medium |
Not every element applies to every part. Appearance approval, for example, is only needed for visible surfaces.
A note on the design FMEA: for build-to-print suppliers working from the customer’s drawing, the design FMEA usually belongs to the customer. The supplier mainly owns the process-side documents (flow diagram, process FMEA, control plan, MSA, dimensional and process studies).
The Five PPAP Levels
The level tells the supplier how much to submit and how much to hold on file.
| Level | What Is Submitted |
|---|---|
| Level 1 | PSW only (plus appearance report if required) |
| Level 2 | PSW with product samples and limited supporting data |
| Level 3 | PSW with product samples and complete supporting data (the usual default) |
| Level 4 | PSW and other items as defined by the customer |
| Level 5 | PSW with samples and complete supporting data, reviewed at the supplier's site |
If the customer doesn’t state a level, Level 3 is generally assumed.
Understanding Initial Process Studies (Cpk and Ppk)
Element 11 is where many suppliers are tested. It uses statistics to show whether a process stays comfortably inside the tolerance.
- Ppk looks at the process over an initial short run.
- Cpk looks at long-term, stable production.
Higher is better. A commonly cited guide is that a Ppk above 1.67 is acceptable for initial studies, values between 1.33 and 1.67 may be accepted by agreement, and values below 1.33 usually need action. The customer’s own requirement always takes precedence.
If a supplier cannot show these studies on the characteristics you marked as critical, treat it as a warning sign.
The Outcome: Approved, Interim or Rejected
After review, the customer gives one of three results:
- Approved: the supplier may ship production quantities.
- Interim approval: limited shipping is allowed for a set time or quantity while open issues are fixed.
- Rejected: the supplier must correct the problems and resubmit before shipping.
How APQP Fits In
PPAP is the end point of APQP (Advanced Product Quality Planning), the structured plan that runs from concept through design, process development and validation to launch. Good APQP means PPAP goes smoothly. Weak APQP leads to repeated resubmissions and delayed launches.
What Buyers Should Ask a Supplier About PPAP
Before you award business, ask:
- Which PPAP level and customer requirements have you worked to before?
- Can you show an example set of documents (with confidential details removed)?
- How do you perform and record capability studies?
- How are gauges calibrated and measurement systems verified?
- What happens to the control plan when the process changes?
- How do you manage change notifications and resubmission?
- Are you certified to IATF 16949 or at least working to it?
Suppliers who answer clearly and show real documents are usually the ones who launch on time.
Common PPAP Problems
- Using the wrong drawing revision
- Capability studies on too few parts
- Control plan not matching what is actually done on the shop floor
- Gauges not calibrated or not suitable for the tolerance
- Changes made without telling the customer
- Submitting late, which delays the start of production
PPAP at ABC
Accurate Bearing Components, in Doddaballapur near Bangalore, has made precision automotive components since 1992. Our quality system is audited to IATF 16949 and ISO 9001, and we hold MSME ZED Gold certification. Parts move through cold forging, CNC turning, heat treatment and phosphate coating under one controlled process route, which makes process documentation and traceability simpler to maintain.
If your customer requires PPAP, tell us the level and any customer-specific requirements in your enquiry. Our RFQ checklist shows what to send. Write to ops@accuratebearing.in or call +91 95357 42213. You can also see our about page and cold forged components.
Table of Contents
FAQs
Production Part Approval Process. It is the set of documents and samples a supplier submits to prove its process can make a part to specification consistently.
The standard lists 18 elements, from design records to the Part Submission Warrant. Not all apply to every part.
The Part Submission Warrant is the signed summary of the PPAP. It states that the parts meet all requirements and lists the reason for submission.
Level 3 is the usual default: PSW, samples and complete supporting data sent to the customer. Level 5 has the same content but is reviewed at the supplier's site.
No. IATF 16949 is a quality management standard for the whole organisation. PPAP is a part-approval process used to release individual parts under it.
After events such as an engineering change, a change in material or sub-supplier, a tooling change, a process or location change, or a long production stoppage, subject to the customer's own rules.
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