Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/359954
As I see It 2 | July - August 2014 | www.machinerylubrication.com There are 8,760 hours in a year. Few plants manage to produce at full capacity for all of those hours. Instead, there are periodic production stoppages due to tooling changes, product changes, scheduled PMs/inspections and unsched- uled downtime (reliability issues). Every hour the plant's assets aren't utilized is an hour of lost revenue and profits. Sadly, many plant managers play games with the numbers by ignoring the poten- tial controllability of "scheduled" downtime. Yes, tooling and product changes are unavoidable, but in most other circumstances, there are often prac- tical ways to minimize lost production from scheduled shutdowns. This can be seen in the difference between typical and top performers in the same industry. For instance, a standard 900-megawatt coal- fired power plant may produce at 86-percent capacity (44 weeks per year), while top performers can exceed 94 percent (48 weeks per year). This is a difference of four weeks of productivity. Still, no classification of work stoppage causes more agony than unscheduled downtime. The reasons are quite obvious, as a recent online survey of Machinery Lubri- cation readers discovered. Following is a list of the top reasons unscheduled downtime is so unwelcome: 1. Production losses and schedule delays (business interruption) 2. Lost revenue and profit (unhappy management/ownership) 3. Promised delivery dates are missed (unhappy customers) 4. The blame game and damaged rela- tionships between operations and maintenance (morale issues) 5. Hurried (botched) repairs cause future problems (cycle of despair) 6. Lack of available replacement parts and skilled trades prolongs the downtime interval 7. Repairs are at a "cost premium" due to rushed parts purchases, use of overtime labor and collateral damage 8. Scheduled "proactive" tasks are replaced by chaotic reactive tasks (leads to future problems) 9. Increased work pressure and job stress (job satisfaction issues) 10. Safety risks due to rushed work, unskilled work, inferior parts, cutting corners, job stress, etc. What Oil Analysis Can Do It's hard for a machine to fail without the oil knowing first. After all, when fail- ures begin and progress over time, there is usually microscopic excavation of machine surfaces producing wear debris. Where does this debris go? It goes into the oil, of course. The oil is like a confessional for the machine. It gets all the bad news quick. For those trying to prevent unscheduled downtime by catching problems early, this is good news. A few years ago Practicing Oil Analysis magazine featured two articles on the differences between vibration analysis and oil analysis in detecting machine faults and impending failure conditions. The articles, which can be viewed at www. MachineryLubrication.com, were written by vibration specialist Howard Maxwell and oil analysis specialist Brian Johnson from Palo Verde Nuclear Generating Station of Arizona Public Ser vice. Palo Verde made a dramatic change in its approach to condition monitoring and machine reliability. The plant combined vibration analysis and oil analysis into a common group, brought its oil analysis onsite and began working as a team. The pie chart in Figure 1 shows the impressive results. Of the 750 machines in the condition monitoring program, bearing faults were first detected 67 percent of the time using oil analysis and 60 percent of the time with vibration analysis. Both tech- the wrAth of Unscheduled dowNtIme o i l A n a l y s i s JIm FItCh NorIA CorPorAtIoN 27% Both 40% Oil Analysis 33% Vibration FiGURE 1. Bearing fault detection of early bearing failure (750 machines) Why Oil Analysis is a Wise and Effective Defense