Every manufacturer ships a nonconforming part eventually. Bores come in oversize, an anodize runs thick, a hole pattern shifts after a bend. What separates suppliers isn’t whether problems happen, but what happens in the hours and weeks after one is found. For a buyer, the most important question is simple: when a part fails inspection, who owns the fix?
Here’s how nonconforming parts should be handled, step by step, and what to expect from a supplier when it happens on your order.
Step 1: Contain the problem
The first job is to stop bad parts from moving. That means identifying and quarantining the affected lot, checking work in process and finished stock for the same issue, and checking whether any suspect parts have already shipped. Good practice is to start containment within 24 to 48 hours of finding the problem. If parts are already at your facility or your customer’s, the supplier should tell you right away, not after the investigation is done.
Step 2: Document the nonconformance
A nonconformance report records what was found: the part number and revision, the lot, the feature and requirement, the measured result, the quantity affected, and how it was detected. Clear records matter for traceability and for spotting repeat problems later.
Step 3: Decide the disposition
A material review board (MRB), usually quality, engineering, purchasing, and production, decides what happens to the nonconforming parts. The standard options are:
| Disposition | What it means | When it fits |
|---|---|---|
| Rework | Bring the part into full conformance using the normal process | The feature can be corrected, such as re-machining an undersize bore |
| Repair | Make the part usable, though not identical to the drawing | Function can be restored; usually needs customer approval |
| Use as is | Accept the deviation without changes | The deviation doesn’t affect form, fit, or function; needs customer approval |
| Return to vendor | Send parts back to the shop that made them | The shop will rework or remake the parts |
| Scrap | Discard the parts | The parts can’t be corrected economically |
For aerospace, defense, and medical programs, “repair” and “use as is” decisions typically require the customer’s written approval, often called a concession or deviation. A supplier shouldn’t make those calls for you quietly.
Step 4: Find the root cause
Fixing the parts isn’t the same as fixing the problem. Root cause analysis asks why the nonconformance happened and why inspection didn’t catch it earlier. Structured methods like the 8D process or five whys keep the investigation honest. A root cause of “operator error” with a corrective action of “retrained operator” usually means the investigation stopped too early. The real cause is more often a fixture, a program, a worn tool, an unclear drawing note, or a handoff where information was lost.
We wrote about where those handoff failures start in Where Quality Escapes Actually Start.
Step 5: Corrective action and verification
Corrective action changes the process so the problem doesn’t come back: a fixture redesign, a program change, an added inspection step, a clarified drawing. When the problem started at a supplier, the buyer typically issues a supplier corrective action request (SCAR). A common timeline is containment within 24 to 48 hours, a completed root cause and corrective action report within about two to four weeks, and verification that the fix worked over the following 30 to 90 days, often by checking the next several lots.
A corrective action isn’t closed when the paperwork is filed. It’s closed when the next lots prove the problem is gone.
Why one owner matters
When a part is machined at one shop, heat treated at a second, and plated at a third, a nonconformance can turn into three companies pointing at each other. The machine shop says the bore was in spec before plating. The plater says it followed the callout. Meanwhile your parts sit in quarantine and your build date slips.
That’s the case for having one company own the outcome: someone who sees the whole routing, has the inspection data from each step, and is responsible for getting you good parts regardless of where the problem started.
How PE handles a failed inspection
Parts come back to San Clemente for inspection before they ship to you, so most problems are caught before they reach your dock. When a part fails our inspection, we quarantine the lot, document the nonconformance, and decide with the shop whether to rework or remake. If a repair or use-as-is disposition is on the table, you decide, with the data in front of you.
We work root cause with the shop that made the part and track corrective action to verified closure. Repeat issues change where future work goes, and a shop can be moved to conditional status or required to requalify. You deal with one project manager the whole time, who knows what happened and when good parts will ship. See The Requalification Follow-Up for how requalification works, and our compliance page and vendor network page for how our quality system is set up. PE is AS9100D Compliant and ISO 9001:2015.
Questions to ask suppliers about nonconformances
- How quickly will you notify me when a nonconformance is found on my order?
- Who decides the disposition, and when do you need my approval?
- Which root cause method do you use?
- How do you verify a corrective action worked?
- If the problem started at a sub-tier shop or outside processor, who manages it?
Frequently asked questions
A nonconforming part is one that doesn’t meet a requirement on the drawing, specification, or purchase order, such as a dimension, material, finish, or documentation requirement.
A material review board reviews nonconforming parts and decides their disposition: rework, repair, use as is, return to vendor, or scrap. It typically includes quality, engineering, purchasing, and production.
Correction fixes the nonconforming parts. Corrective action fixes the cause in the process so the problem doesn’t happen again.
Send us the drawings.
A real person will contact you within 24 hours.
