Paper cup machine alarm history is most valuable when it identifies the first abnormal event, not when it becomes a list of every message shown after the machine stops. A recurring-fault root cause review connects alarms with machine state, cup format, material, station sequence, maintenance and previous corrective actions. This prevents repeated resets and parts replacement without proof.
Preserve the event before recovery
When safe, photograph the complete alarm screen, not only the final message. Record date/time, machine model, operating mode, speed state, cup format, material lot, last completed action and operator observation. Export or copy the alarm history by the approved method before acknowledging or cycling power.
A stop at one station can generate secondary messages from downstream sensors, drives and collection devices. Build the sequence in time order. If HMI and controller clocks differ from the factory record, document the offset rather than silently rearranging events.
Build a recurring-fault record
| Record field | Minimum evidence | Why it matters |
|---|---|---|
| First event | Exact code/text, source device, timestamp and preceding machine action | Separates initiating fault from cascade alarms |
| Operating context | Mode, speed stage, warm-up, stop/restart state and shift | Shows conditions required for recurrence |
| Product/material | Cup/tool format, paper/coating lot and sample result | Reveals whether the fault follows an input |
| Physical location | Station, carrier, sensor/actuator and marked defect | Connects software history to the real mechanism |
| Recent change | Maintenance, replacement, cleaning, parameter, jam or changeover | Identifies introduced variation |
| Action and proof | Hypothesis, test, result, rollback and accepted cycles | Prevents the same unverified action being repeated |
Define the recurring pattern objectively
Group events by exact code/source and by symptom, but do not merge different faults merely because they stop the same station. Calculate how often the issue occurs per defined production time or cycle count and map it to startup, steady operation, material refill, speed change, format change, cleaning or a particular shift.
Record successful periods too. “The alarm did not occur” is meaningful only when the machine ran long enough under the same conditions that previously produced it. A restart that runs for five minutes cannot close a fault that normally appears after several hours.
Connect alarm, command, response and product
For each event, ask four questions: What did the controller expect? What input or feedback did it receive? What did the mechanism physically do? What happened to the cup or blank? A sensor alarm may be caused by a missing product, a failed pickup, a late actuator, target misalignment, wiring or the sensor itself.
Use the relevant station guide rather than changing unrelated parameters. For example, the sensor and interlock troubleshooting guide separates input, target and sequence evidence, while the pneumatic system guide separates command, pressure-under-load and actuator response.
Test one root-cause hypothesis at a time
Write the proposed cause and the evidence that would support or reject it. Use a safe controlled test: compare an accepted material lot, inspect a connector under isolation, verify a sensor target, trend pressure, reproduce a documented speed stage or restore a known configuration. Preserve the original state and rollback path.
Do not replace several parts or change multiple settings in one attempt. Even if the fault disappears, the factory will not know which action mattered and cannot prevent recurrence. Parts removed without proof should remain identified for inspection rather than being discarded immediately.
Control software, parameters and recurring resets
Repeatedly resetting a trip can erase evidence and expose the machine to damage. Stop escalation if the fault involves safety, collision, overheating, smoke, severe vibration, electrical risk or an undefined motion. Protected parameters, PLC logic, drive settings and safety functions require supplier or qualified specialist involvement.
Back up and compare configuration before any authorized change. The HMI and PLC communication guide explains device and version control; the change control guide keeps the machine history auditable.
Define closure by evidence, not by silence
After the verified correction, restore guards and use the approved restart sequence. Run through the conditions that previously triggered the event and define a sufficient observation window. Check alarm history, machine sequence and finished cups at the authorized stages.
Close the issue only when the initiating event no longer recurs, no new fault has been introduced and product quality remains accepted. Record the root cause, correction, part or setting reference, verification duration/cycles, samples and approver. If the root cause is not proven, label the action as containment and keep the investigation open.
Frequently asked questions
Is the last alarm on the screen usually the root cause?
No. It may be a downstream consequence of an earlier stop. Preserve the full sequence and identify the first device or condition that changed abnormally.
Can a fault be closed because it disappeared after power cycling?
No. Power cycling may reset evidence or temporarily restore a device. Reproduce the relevant operating condition and verify the initiating cause before closure.
What is the difference between containment and corrective action?
Containment limits immediate impact, such as quarantining a material lot. Corrective action removes a verified cause and includes evidence that recurrence is controlled.
When should the machine supplier receive the case?
Escalate for protected settings, program or drive issues, repeated unexplained stops, safety-related alarms, component damage or when the factory cannot safely test the next hypothesis from supplied documentation.
Send the machine model, complete alarm history, event timeline, operating context, material/tooling identity, marked samples, safe videos, recent changes and tests already performed through our inquiry page. HANNAI can review the evidence and help prioritize the next controlled step.