Sample investigation— a real scenario, fully worked through. Read-only.Request access →

Metal fragments detected in depositor output — Line 3

CriticalProduction · Line 3·Signed off — 4 days

✓Define the problem

✓Contain it

✓Find the cause

✓Prove it

✓Decide actions

6Close out

● verified · assumed · ◆ root cause · → handed to another team

Coach conversation

Let's get into it. In your own words — what happened?

We found metal pieces coming off the chocolate depositor on Line 3. X-ray picked up three pieces in about 30 minutes of production.

Metal in the product — that's a serious one. Good that the X-ray caught it. What did you do straight away to contain it?

We stopped the line immediately and quarantined everything from that run. About 800kg on hold.

Fast and decisive. Now let's find where it came from. Maintenance checked the depositor head — what did they find?

They stripped it down and found the scraper blade had a section missing. That's the source.

Direct cause confirmed — scraper blade damage. Now the real question: how long had the blade been like that, and was there any way to spot it before it got to this point?

We don't know when it happened. The PM sheet doesn't include scraper blades — they've never been on the checklist.

There it is. The blade wasn't in the PM schedule — so there was no systematic way to catch wear before it became a failure. That's not an equipment problem, that's a process gap. When was that PM checklist last reviewed?

2019. It's never been updated since it was written.

That's the root cause. A PM schedule written in 2019, never revisited, with no mechanism to catch wearing parts on critical contact equipment. The blade failing is a symptom — the real failure is in the maintenance planning system. Great work getting to this. Now let's make sure it can't happen again. Three actions we need: replace all depositor scrapers across all lines now, add scraper blade inspection to the PM checklist, and audit every PM checklist that hasn't been reviewed in over two years. Who's the right person to own each of those?

Causes recorded

✓X-ray detected 3 metal fragments in 30 min of depositor outputMeasurement
✓Scraper blade on depositor head had a section missingEquipment
✓Scraper blades were not included in the weekly PM inspection checklistMethod
★PM checklist written in 2019 — never reviewed or updatedMethod

Corrective actions

✓
Replace all depositor scraper blades — Lines 1, 2 & 3
Engineering · Completed same day
✓
Add scraper blade inspection to weekly PM checklist
QA Manager · 30 days
✓
Audit all PM checklists last reviewed >2 years ago
Engineering Manager · 60 days

✓ Signed off & closed

Metal contamination on Line 3 traced to a worn scraper blade on the chocolate depositor head. Direct cause: blade failure. Root cause: scraper blade inspection was absent from the PM schedule — a maintenance planning gap, not an individual error. PM schedules had not been reviewed since 2019. All three Line depositor scrapers replaced immediately. Scraper blade inspection added to weekly PM checklist. Full PM schedule audit (all checklists >2 years old) assigned to Engineering Manager by end of Q3. Detection system (inline X-ray) functioned correctly. No product left the site. 800kg quarantined and disposed.

Ready to run your own?

The coach walks you through every step — you just answer the questions. Most teams finish in under 20 minutes.

Request access →