Breakdown Analysis is the structured investigation of an equipment failure to understand what happened, why it happened, and what should change to reduce recurrence.
The goal is not to complete a report.
The goal is to learn enough from the failure that the system becomes more reliable.
Start with the failure event
A useful investigation begins with facts.
Capture:
- what equipment failed;
- what function was lost;
- when the failure occurred;
- operating conditions;
- alarms;
- product or process conditions;
- maintenance history;
- recent changes;
- physical evidence;
- actions taken during recovery.
The first description should explain the failure event, not assign blame.
Symptom is not cause
Statements such as these are usually symptoms:
- bearing failed;
- motor overheated;
- belt broke;
- sensor stopped working;
- fuse blew;
- pump seized.
The investigation must go deeper.
Why did the bearing fail?
Possible mechanisms might include:
- contamination;
- poor lubrication;
- misalignment;
- incorrect fit;
- overload;
- installation damage;
- electrical fluting;
- excessive temperature.
Replacing the failed component restores production but does not necessarily prevent recurrence.
Preserve evidence
Breakdown evidence disappears quickly.
Parts get discarded.
Machines are cleaned.
Adjustments are changed.
Operators leave the area.
Logs are overwritten.
Before returning everything to normal, capture the evidence required for investigation:
- photos;
- failed parts;
- alarm history;
- process trends;
- lubrication condition;
- measurements;
- witness observations.
This follows the same principle as Gemba: understand the actual condition.
Reconstruct the timeline
Create a simple sequence:
normal operation → first abnormal signal → degradation → functional failure → response → restoration.
The timeline can reveal important relationships.
For example, a temperature increase may have started hours before the trip.
A vibration change may have appeared after maintenance.
A recurring alarm may have been reset several times before the failure.
Use structured cause analysis
Root Cause Analysis provides the broader investigation logic.
5 Whys can help trace causal mechanisms.
Fishbone or 4M Analysis can help organize possible contributing factors.
The method matters less than the discipline:
- use evidence;
- distinguish cause from correlation;
- verify assumptions;
- avoid stopping at operator error;
- test whether the proposed cause explains the failure.
Separate physical, human, and system causes
A strong breakdown analysis often considers three levels.
Physical cause
What physically failed?
Example: bearing race damaged by inadequate lubrication.
Human or task cause
What action or condition allowed the physical cause?
Example: lubricant was not replenished at the required interval.
System cause
Why did the maintenance system allow that condition?
Example: the lubrication task was missing from the PM plan, ownership was unclear, or the standard was not practical.
Stopping at the physical cause often produces only component replacement.
Connect breakdown analysis to maintenance strategy
The investigation should influence the maintenance program.
Possible outcomes include:
- PM task change;
- lubrication standard change;
- condition-monitoring task;
- spare-parts change;
- operator inspection;
- design modification;
- training;
- setup standard;
- alarm response;
- supplier correction.
Planned Maintenance and Predictive Maintenance should evolve based on what failures teach.
Prioritize significant failures
Not every minor stop requires a full investigation.
Use criteria such as:
- safety consequence;
- quality impact;
- downtime;
- production loss;
- repair cost;
- recurrence;
- environmental risk;
- customer impact.
OEE and downtime Pareto data can help identify chronic equipment losses.
Common mistakes
Replacing the component and closing the case
Restoration is not prevention.
Blaming the operator
Human error should trigger questions about system design, standards, training, interfaces, and workload.
Brainstorming without evidence
Possible causes are not confirmed causes.
Creating actions unrelated to the cause
More training is not useful if the failure mechanism was poor lubrication design.
Never updating maintenance tasks
The organization loses the learning value of the failure.
A practical breakdown-analysis sequence
- Stabilize the situation safely.
- Preserve evidence.
- Define the failed function.
- Reconstruct the timeline.
- Identify the physical failure mechanism.
- Investigate contributing task and system causes.
- Verify the causal explanation.
- Define corrective and preventive actions.
- Update maintenance standards and tasks.
- Monitor recurrence.
The practical lesson
Every significant breakdown contains information about the weaknesses of the maintenance system.
The value of Breakdown Analysis is turning that information into prevention.