Lachance on CMMS
May 01, 2013
CMMS conventional wisdom tells us to schedule our machine preventive maintenance (PM) items on a calendar just like we do for our car tune-ups. It's been 90 days, so it must be time to re-calibrate the auger in the extruder, or replace the impeller on a centrifugal pump. But what if it's too early to check and replace a part?
While being reactive and waiting to make repairs only after equipment fails hurts productivity, changing parts before the end of their run is also a waste of time and money. If you're doing too many PMs based on a calendar and you're wasting precious maintenance resources to do the work, you may want to consider more efficient options. To preserve equipment and ensure plant floor machines are fully operational and reliable, safe, and long-lasting, consider more proactive PMs.
PMs come in many shapes and sizes. Meter readings offer greater PM intelligence. Let's say a piece of equipment has fallen below the acceptable performance threshold, slowing down production and reducing output. Meter trending may show that widget output falls after 600 hrs of continued use, which may exceed the manufacturer's recommendation for replacing components. Meter readings to periodically check production volumes and perform the necessary maintenance tasks trump calendar-based PMs, which remain static as production volumes change over time. And you risk scheduling too few or too frequent PMs that won't parallel the growth of the company.
Another useful PM, condition-based maintenance (CBM), is based on the health of your asset. CMB-based PMs can prevent degradation of components in the equipment. CBM incorporates real-time data about machine health so that maintenance work can be done when it is actually necessary—and not according to a rigid calendar schedule. Monitoring machine health by controlling oil corrosion with a PM to change filters prevents failures.
Checking oil levels, contaminants, temperatures, vibration levels, (among others) all fall under CBMs. A civil engineering company that manages wastewater treatment plants has to regularly test conditions of its centrifugal blowers for alignment, temperatures, vibrations, etc. Each blower has a gearbox with an oil capacity of 27 gal. CBM tests allowed the maintenance team to analyze lab results for detecting metal in the oil, resulting in less frequent oil changes—and lower maintenance costs.
This way the condition of the equipment drives the schedule—not the calendar.
Read more articles by Paul on his blog, Lachance on CMMS.