January 4, 2017
Maintenance Strategies: Part One
By Mac MacCormack
In the current highly competitive global economy we live in, there is always a drive to get the competitive edge. One way is to develop a maintenance strategy that will improve safety, meet production goals, increase uptime, increase plant efficiency and thus increase plant profitability.
There are four basic maintenance strategies:
- Breakdown Maintenance
- Preventive Maintenance
- Predictive Maintenance
- Proactive Maintenance
This month, let’s take a look at the pros and cons of breakdown maintenance also known as run to failure, reactive or hysterical.
For many years (and still today in many plants) the philosophy has been to simply run the machine until it failed, deal with it via repair or replacement. Little thought was given to improving equipment reliability. The maintenance department was considered a huge cost sink, budgeted for and nearly impossible to budget accurately.
The following picture shows a bearing failure in centrifugal pump.
As you can see, there is much more damage than to the bearing alone. Also, the indirect cost of these failures are most often much higher than the direct costs.
So when or why would one choose breakdown maintenance as a strategy?
- If a machine is not critical, does not impact production, is highly redundant, is inexpensive to repair or replace and is unlikely to cause collateral damage, injury or other problems if it fails.
- If it is not cost effective to monitor the machine, there are no benefits of preventive maintenance actions.
- There are also cases where a machine is being monitored and is known to be at risk of failure but a decision is made to continue running the machine anyway in order to meet production demands. The hope in this case is that the machine will survive until after production needs are met and the indirect cost of stopping production exceeds the cost of repair or replacement. This decision would fall into the Risk Management category. It’s been my experience that more often than not, the at risk equipment does not make it.
Next month: Preventive Maintenance.