A paper cup machine bad actor review identifies assets or failure modes that repeatedly consume downtime, maintenance effort, scrap or attention. Ranking should lead to a focused investigation, not label a machine or technician from raw event counts.
This article explains review structure and does not establish universal loss thresholds. Use validated downtime, quality, work-order and production data, then apply the site corrective-action process. Keep ranking logic stable for the review period and publish the exposure basis with results. Do not use the label to assign blame or bypass a separate risk decision for a high-consequence event. Reconcile data-source revisions before comparing one period with another. Preserve rejected hypotheses and the evidence that ruled them out so future reviews do not repeat unsupported conclusions.
Diagnostic decision table
| Review signal | Normalization | Common bias |
|---|---|---|
| Downtime duration | Operating exposure and event boundary | Calendar total only |
| Failure frequency | Consistent event and reset rules | Count every alarm |
| Quality loss | Affected output and detection | Scrap quantity alone |
| Maintenance effort | Active and waiting components | Labour cost only |
Define the purpose and population
State whether the review targets machine systems, components, failure modes or line positions. Select a time and exposure basis that supports the decision. Include all comparable machines and relevant operating states.
Do not change the population after seeing the ranking. Document exclusions such as commissioning periods or external utility loss. Preserve the raw event list so the result can be reproduced.
Validate event identity and boundaries
Reconcile downtime codes, alarms, work orders, operator notes and quality holds. Group repeat resets that belong to one unresolved episode according to the defined rule. Separate symptoms from diagnosed failure modes.
Check timestamps and stable-production return. Duplicate events can exaggerate frequency, while one long open event can hide repeated intervention. Mark uncertain records instead of silently assigning a cause.
Rank more than one loss dimension
Review duration, frequency, scrap, maintenance effort, safety or quality consequence and recurrence. Normalize by operating hours, cycles, product family or another valid exposure when comparisons differ.
Use Pareto views as starting points. A frequent short stop may need process control, while a rare high-consequence failure may require engineering action despite a low count. Keep these decisions visible.
Investigate mechanisms and systemic contributors
Select the priority problem and preserve as-found evidence. Review configuration, parts, environment, operating practice, maintenance quality, detection and previous corrective actions. Test hypotheses against data and physical evidence.
Avoid treating the last replaced component as root cause. Repeated bearing, sensor or seal changes may point to alignment, contamination, wiring, selection or job-plan weaknesses. Use supplier expertise when evidence supports escalation.
Verify action and prevent ranking drift
Assign action, owner, due date, expected mechanism and outcome measure. Confirm installation and monitor the same normalized loss after change. Check for transferred defects or new operator burden.
Keep the asset on review until effectiveness evidence is adequate. Send HANNAI event timelines, machine identity, failed-part evidence and configuration details when technical support is needed.
Related equipment and next checks
Review the paper cup production line and the related guide to paper cup machine downtime coding guide. The Engineering Notes archive connects these checks with wider machine planning.
Frequently asked questions
Is the machine with most alarms always the bad actor?
No. Validate events, exposure and consequence first.
Should duration and frequency be combined?
Review both because they suggest different actions.
Can a replaced part be called the root cause?
Only when evidence explains why it failed.
When can an item leave the review list?
After the corrective mechanism and sustained outcome are verified.
Review the evidence with HANNAI
Send your machine model, component identification and the observations described in this guide. Include the drawing or material reference and any before-and-after measurements so the required next check can be identified.