Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/431954
32 November - December 2014 | www.machinerylubrication.com July 2011, and no failures have occurred since. While this was not a huge cost savings, it was a nuisance to both mechanics and techni- cians. Previously, mechanics had to replace the pump four to six times a year, and technicians had to walk in 4 to 6 inches of wet slop each time the pump failed. Wet Mill Gearbox A wet mill gearbox was failing every three to four months over a two-year span. The failures would upset the process system and reduce production by 40 percent whenever the conveyor was down. In February 2011, the maintenance team designed a new seal. The gearbox has not failed since. Finished Product Pump A finished product pump failed every three months over a five- year span. After many attempts to fix it, the problem was finally corrected in May 2012. The pump was then replaced in November 2013. The correction prevented five failures before the pump was replaced for a savings of more than $400,000 when factoring in product reduction during the 12 hours the system would be down. Finished Product Recompressor A finished product recompressor was rebuilt and modified over a five-day shutdown. When the compressor was started, onsite oil analysis found water in the oil. Root cause analysis showed that the heat exchanger had developed a leak while it was down. The oil analysis saved more than 18 hours of downtime for a savings of $140,000. This did not include the possible damage to the new equipment. Pump and Motor MTBF Through root cause analysis, better lubrication practices, vibra- tion and oil analysis, an improvement in mean time between failures (MTBF) for both pumps and motors was achieved. Since MTBF was tracked in 2009, pump life increased from 50 months to 63.2 months as of December 2013. This was an increase of almost 25 percent in pump life over five years. The motors had an even greater increase of 78 percent from 148 months in January 2009 to 263.5 months in December 2013. Final Thoughts and Suggestions A root cause analysis program can offer benefits for almost any plant. It eliminates repeating problems and allows you to focus on other issues. Always try to gather as much information as possible. If you don't solve the problem the first time, the additional informa- tion may be useful for a future solution. Along those same lines, you should include as many people as possible in the root cause meeting. This will enable you to form a team of people who care about the problem and are involved in the decision-making or changes. Although you may come up with a solution, it doesn't necessarily mean that it will get accomplished. You must follow up on the suggestions and assign individuals to each of them for accountability. If someone is not tracking the changes, they will never be completed. Concentrate on the easy wins and the critical big problems. The easy wins will get some buy-in from other areas of the plant, which will cause others to want to be more involved in the solu- tions. The critical problems are those that will have the most impact on the plant, either the most repeated failures or the most savings if eliminated. In terms of costs, track the savings from the changes that have been made during the analysis. You may not track every single change but be sure to include the more valuable ones. This will give you the opportunity to justify the program's value. Form a team to help gather information and come up with solutions. If you try to do it all on your own, you will not succeed. There are simply too many items to track and changes to make. While you would like to have the entire plant as part of your team, utilize trusted technicians and maintenance personnel who have shown some interest. Provide feedback on how they have helped, when the changes will be made and if they were successful. The more of an impact they feel they have, the more they will want to help. As you create your team, don't focus on whose fault it was but rather on what the problem is and how to reach a solution. In the end, the goal is to eliminate the source of the issues instead of the person who did the wrong thing. Finally, relay to everyone involved that root cause analysis is performed to help everyone at the plant. The more people believe this and see the difference that it can make, the more they will want to be involved. More importantly, when they realize how it can help them, they not only will give you more information, but they also will come to you with their problems because they know that you produce results. ROOT CAUSE ANALYSIS 2010-2013 Pump MTBF - Loudon Plant 2009-2013 Motor MTBF - Loudon Plant These examples show how root cause analysis can lead to improvements in mean time between failures for a plant's pumps and motors.