What does a useful PFMEA example look like from a machining or die casting supplier?

What goes into a process FMEA under the current method?

A current-method PFMEA is built in seven steps, from planning and a structure tree of process steps down to a failure chain of effect, mode and cause for each step, with prevention and detection controls rated on separate scales. The output is a ranked list of actions, not a score sheet.

The 2019 handbook, published jointly by AIAG and the German VDA, replaced the older AIAG fourth-edition approach and is the basis many automotive and industrial customers now reference. Its seven steps are planning and preparation, structure analysis, function analysis, failure analysis, risk analysis, optimization and results documentation. In practice, three of them decide whether the document is useful.

• Structure analysis. The process steps come straight from the supplier’s process flow diagram, and under each step sit the work elements that can cause trouble, usually grouped as man, machine, material and environment, sometimes with method and measurement added. If a step exists on the router but not in the PFMEA, it was never analyzed.
• Failure analysis. Each step gets a failure chain: the failure mode (what the step produces wrong, such as a bore oversize), the effect (what you see at your assembly or in the field) and the cause (which work element produced it, such as an insert worn past its life).
• Risk analysis. Severity rates the effect, occurrence rates the cause in light of its prevention controls, and detection rates how well the detection controls catch the mode or the cause before the part leaves. All three use 1-to-10 scales defined in the handbook.

The handbook also retired the risk priority number, the product of the three ratings, as the way to rank work. It uses an action priority table instead, which weights severity first, then occurrence, then detection, so a high-severity failure with weak controls is flagged even when its product looks modest. An older PFMEA ranked by risk priority number is not wrong, but it is a sign the document predates the current method and may not have been reviewed since. The ASQ overview of FMEA gives the general logic for readers outside automotive, and the IEC 60812 standard covers the same technique in a sector-neutral form.

How can you tell a supplier’s PFMEA is boilerplate?

A boilerplate PFMEA could be stapled to any part number: its steps are generic, its causes are vague, its ratings are uniform and nothing in it has ever produced an action. Check it against your drawing and the supplier’s own process flow, and the gaps show quickly.

Use these checks in order. Each one takes minutes and each one fails a template outright.

1. Part number and revision. The header should carry your part number, the drawing revision it analyzes and its own revision history. A PFMEA dated before your latest drawing revision has not seen the change.
2. Step match. Lay the PFMEA beside the process flow diagram and the router. Outside processing, rework loops, washing and packing are the steps most often missing.
3. Your critical features. Every characteristic you marked as critical or special on the drawing should appear as a failure mode with its own row, and its severity should reflect what you told the supplier about function. If you never told them, a generic severity is your gap, not theirs.
4. Specific causes. “Operator error”, “machine malfunction” and “wrong material” are categories, not causes. A real cause names something that can be controlled.
5. Rating spread. If most rows carry the same occurrence and detection values, nobody rated them. Real ratings vary with the controls in place.
6. Controls you can see. Pick two controls and ask for the evidence: the gauge, the tool-life setting, the check sheet. On a site visit or a live video walk-through, look for them at the machine.
7. Closed actions. A mature PFMEA shows actions taken, with dates, and re-rated rows after them. Lessons from returns and corrective actions should feed back into it.

One caution in the other direction: a long PFMEA is not a better one. A document with hundreds of rows of handling and labeling failures on a simple bracket usually means the template was copied in full. Depth belongs on the features that carry function.

How should the PFMEA connect to the control plan and the drawing?

The process flow, the PFMEA and the control plan should share the same step numbers, and every detection control in the PFMEA should reappear in the control plan with a method, sample size and frequency. If the two documents disagree, the control plan is what the floor runs.

The chain works like this. Your drawing marks the characteristics that matter. The PFMEA rates the risk on each and decides which controls are needed. The control plan turns those controls into instructions: which gauge, how many parts, how often, and the reaction when a check fails. The inspection records then show the controls were run. Break any link and the PFMEA becomes a desk exercise.

Where the PFMEA calls for a capability study on a characteristic, the control plan should say how the data are collected, and the guide to Cpk vs Ppk explains which index fits a launch and which fits ongoing production. Where it relies on first-piece checks after each setup, the first article inspection guide covers what that report should contain. And because both documents live and change, ask that each carries a revision level and that the PFMEA is reviewed whenever the drawing, the tooling, the process or the site changes, and after any significant nonconformance.

What process documents does Saola provide today?

Saola’s published documentation set does not list a PFMEA as a standard document, so if your approval needs one, say so on the RFQ and ask for it to be answered with the quote. What the quality page does list is a process routing sheet on request, a first-article inspection report, a dimensional record with every lot, and work to a control plan you supply.

The plant runs die casting, CNC milling of its own castings, CNC turning and surface finishing on one site, so a single process flow can cover the whole routing. The quality page lists the process routing sheet per part number on request, a first-article report covering every toleranced dimension, a dimensional inspection record with every lot, salt-spray results at first article and on request, and material certification on request. It also states that dimensions you mark as process-capability control points are checked more often than the rest of the print, and that the plant builds its inspection around a control plan or cosmetic standard you send. ISO 9001 certification is in progress; no third-party quality audit report exists yet.

The factory page shows the kind of risk reasoning a PFMEA formalizes: for a die-cast base with drilled and tapped holes, the inspection plan was written before the first shot, with machined holes checked on every part because a drill can wander on any cycle, and cast features checked at a fixed interval because they move only as the tool wears. If you need that reasoning delivered as a PFMEA in the AIAG & VDA format, put it on the quote request together with the drawing and the critical characteristics.