Equipment maintenance and repairs can be a significant portion of your company's expenses. Analyzing performance data such as the mean time between unscheduled removals and the mean time between failures can help you decide when it is more cost-effective to upgrade to higher quality equipment than to keep replacing the defective units.
Preparing Your Facility
The MTBF metric gives you an idea of how long your equipment can run before a critical component malfunctions. You must be able to accurately measure your operating time or your calculations will be unreliable. If your equipment does not include a built-in timekeeping device, you may need to instruct the operator to monitor the running time with a stopwatch during the time period for which you will be analyzing the equipment's performance.
Calculating the MTBF
Total all of the hours the equipment was running with no problems during the specified time period. Count the number of units that failed and could no longer perform their intended function during the same span of time. Divide the number of hours by the failures that occurred to find the MTBF. For example, if there are 10 failures in a period of 1000 operating hours, the MTBF would be 100 hours.
Calculating the MTBUR
The MTBUR metric focuses on equipment that has failed to the point that it must be completely removed from service before its expected retirement date. Divide the total operating hours by the number of unplanned removals from service during that time period. For example, five removals from service in a span of 2500 hours would result in an MTBUR of 500 hours.