A defect claim goes out and a three-page document comes back with a photograph, a cause and a promise to be more careful. It looks like an 8D. It is not. The difference between a real 8D and a courtesy reply is evidence, and it decides whether the same defect returns in the next batch.
This guide is part of our Charger Quality & Inspection. Read the full topic guide for the decisions that come before and after this step.
Why an 8D is a document trail, not an apology
The eight disciplines exist to force a defect through a defined sequence: describe it, contain it, find the cause, fix it, prove the fix, prevent recurrence and close the loop with the customer. Each discipline produces evidence. A supplier that skips the evidence produces a narrative, and narratives do not prevent recurrence.
D1 to D3: team, description and containment
D1 names the team and the owner. D2 describes the defect in measurable terms: which model, which batch, how many units, what the failure looks like, and how it was detected. D3 is containment: what happened to the suspect stock, both in the factory and in transit. Containment is the most urgent discipline because it protects the customer from the rest of the affected batch. If D3 is missing or vague, the report stops there.
D4: root cause that survives the five-why test
A root cause must explain why the defect occurred and why it was not detected. “Operator carelessness” fails both tests. A credible root cause points to a specific condition: a fixture that allowed a connector to seat at an angle, a test limit that did not cover a parameter, or a component substitution made without notification. Ask whether the cause explains the observed defect rate, not just the single unit in the photograph.
D5 and D6: corrective action and validation
D5 is the permanent corrective action; D6 is the evidence that it works. Together they are the core of the report. Validation can be a test result, a process capability figure, an inspection result on a defined sample, or a comparison before and after. What it cannot be is a statement that the team will be more careful. Where the action changes a component, a fixture or a test limit, the validation should show the new condition in place and the affected units conforming.
D7: preventing recurrence system-wide
D7 asks whether the same failure could appear in another product, line or shift. A connector that can be mis-seated in one model can usually be mis-seated in a sibling model. A credible D7 reviews the platform and updates the relevant work instructions, fixtures or FMEA. This is the discipline most often reduced to a sentence, and it is the one that prevents the next claim.
D8: closure and customer acknowledgement
D8 closes the report with the customer’s agreement. Before agreeing, confirm that the containment covered all suspect stock, that the corrective action is implemented rather than planned, that validation evidence is attached, and that the affected inventory decision is stated: rework, scrap, replace or ship as is.
| Discipline | Evidence expected | Common stub |
|---|---|---|
| D3 Containment | Stock location, quantity, disposition | “Sorting in progress” with no numbers |
| D4 Root cause | Condition, detection escape, data | “Operator error” |
| D6 Validation | Test or inspection result after the change | “Will monitor” |
| D7 Recurrence | Platform or process review | One sentence with no scope |
How to score a supplier 8D in ten minutes
- Does D2 give numbers – units, batch, detection point?
- Does D3 state where the suspect stock is and what happened to it?
- Does D4 name a condition that explains the failure rate?
- Does D6 attach a result rather than a promise?
- Does D7 cover the platform, not just the batch?
- Is the inventory disposition stated for units already produced?
When to reject a report and demand a redo
Reject the report when containment is incomplete, when the root cause does not explain the defect, when the corrective action is written but not implemented, or when validation evidence is absent. Rejecting is not a confrontation; it is the mechanism that makes the process work. A supplier that treats an 8D as a formality will treat a corrective action the same way.
FAQs
How quickly should an 8D be issued after a defect claim?
Containment should be communicated immediately, within a day, because it protects the rest of the stock. The full report with validated corrective action takes longer, and the timeline should be agreed in the warranty or quality annex.
What is the difference between containment and correction?
Containment stops the problem from reaching more customers, usually by sorting and holding stock. Correction removes the cause so the problem does not recur. Both are required.
Does an 8D expire?
The report closes, but the corrective action remains in force. It should be verified again during subsequent audits or when the process changes, particularly if a component or fixture is modified.
Next step
Wecent Group handles defects through a documented corrective-action process with batch traceability behind every claim. Send your quality requirements or a sample claim scenario to the contact page. Related reading: rework and re-inspection, quality control, batch traceability and inspection gates. External references: AIAG, ISO 9001, ISO 2859-1 sampling, GS1 standards, IEC standards and UL.
More on this topic: wireless charger manufacturing and multiple device charging stations, wireless charger adapters.