by Christer Idhammar
Preventive maintenance (PM) is often set up in a very inefficient way in many mills. It is typical to see that the PM program is work order driven instead of route driven. Many PM tasks are still done while equipment is down because this was how it was set up, and no one has ever questioned whether this is still needed, or guard design prohibits on-the-run inspections, etc.
Because the system is work order driven, the execution of PM tasks is often very ineffective. For example, a PM system that was recently analyzed revealed that inspection of six limit switches on a sludge press took one hour for an electrician every week. This was because the PM system was work order driven and issued one work order per inspection, and the inspection included travel time. A good inspection of six limit switches on the run in a route-driven system should not take more than five minutes, and it could be integrated with mechanical inspections of the sludge press or done by an operator. Continue reading →