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Fig. 4. Improving the lubrication process based on data collection has led to a reduced number of motors replaced per year at Aarrowcast.


Fig. 5. Equipment uptime has trended upward since predictive maintenance was started at Aarrowcast.


and what other effects it would have on bearing life, energy, and periodic maintenance intervals (Fig. 2). With 2012 as a benchmark, the com- pany discovered that by 2015, it has recorded $36,000 in energy savings, increased bearing life by 200% and reduced vibration from the baseline by about 50%. Lubrication is historically


performed as a continuous process using automatic lubricators or as a scheduled routine. Using ultrasound to optimize the continuous and manual process, Aarrowcast adjusted the lubrication rates based on when the bearing needed it and by how much. Figure 3 shows how replace- ments have trended down- ward since 2012. In 2015, several scheduled motor replacements were made based on scheduled main- tenance during a planned shutdown. Historically, motors at


Aarrowcast were taken out of service by routine or scheduled maintenance. By improving the lubrication process and adjusting or


delaying the periodic replacement, the metalcaster has seen a dramatic reduc- tion in the number of motors being replaced annually (Fig. 4). In this case, if it’s not broke, don’t fix it, applies. Under normal use, motors have a rather long pass/fail curve, making them ideal candidates for a predictive maintenance strategy.


Uptime related to how often the


machine runs to specification when the operator turns on the switch and how well it stays running to the end of the shift is perhaps the most watched metric of all. Figure 5 shows the historic trend of all production lines at Aarrowcast from the onset of its predictive maintenance effort to the end of 2015. Currently, the metalcasting facility is operating in the 97-98% range. Piece counts per hour have also been improved through other continuous improvement efforts.


In the end, what’s it


Fig. 6. With data collection and predictive maintenance, Aarrowcast is better able to budget maintenance costs month to month.


worth to the company to be able to predict and sustain what is planned to be spend for maintenance? When Aarrowcast started its predictive maintenance strategy with one part-time personnel, the depart- ment was, on average, over budget. By 2013, when two full-time personnel were dedicated to predictive maintenance, spending was under budget and it has stayed that way since.


October 2016 MODERN CASTING | 29


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