Concerning Alignment, Grease and Oil

Jim,

Great idea on lubricants. Although it may be better to monitor this secretly as enterprising managers may find a way to beat the system (aghast did I write that?).

Still teaching in Prattville.

Ride, ride, ride.

Gene Canavan
Prattville, Alabama, USA

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Interesting your choice of maintenance KPI. SKF monitors lubricant usage at the sites we provide performance-based outsourcing, for the same reasons you discussed, e.g., if a mill is in trouble from an equipment reliability standpoint due to ineffective or non-existent maintenance practices.

At those sites we take responsibility for an agreed level of unplanned mechanical downtime occuring in the mill (with certain qualifications, of course). Besides tracking unplanned mechanical downtime, we also monitor bearing expenses per ton (unit) and lubricant costs per ton among other Key Performance Indicators. We believe as you have stated, that two indicators of reliability performance are your bearing and lubricant spend.

...Would you rather be spending $275K for lubricant to maintain 1,000,000 tonnes of production (1,000,000 x $0.27) than to continue spending $353K for the 436,000 tonnes (436,000 x $0.81) you were making at the same site earlier? Of course this site had a significant capacity increase in the interim helping to decrease per tonne costs, but what would be the new costs if certain improvement programs starting in year 1 had not been enacted?

John Yolton
Eureka, California, USA

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Jim,

I wanted to start off by saying that I truly enjoy your write ups and find your way of simplifying complex things very refreshing.

I would like however to caution you on your analogy of measuring lubricant consumption as a leading KPI. With greases and oils, more is not always better. If you do a quick research and find a Stribeck curve and read up you will find out that too much lubrication can sometimes be worst than not enough when is comes to bearing reliability. With electric motors, over-lubricating often results in electrical failures as the extra grease ends up in the windings. I am sharing this with you based on my personal experience here at SLP as we have over achieved on motor lubrication and are paying the price.

Unfortunately, I have no suggestion for simply monitoring lubrication. At this mill, the best we can do is add up bearing usage, cut up every bearing that fails and analyze the failure modes. When rust and pitting is present, we try to increase lubrication, when signs of overheating are present we often cut back. Our vibration and ultrasonic measurements sometimes warns us that a bearing is under lubricated, but that's been "hit and miss".

Keep up the good work!

Joel St-Pierre
Maintenance and Engineering Manager
Slave Lake Pulp

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Jim;

I would disagree with your statement that 75% of failures are due to misalignment or lubrication. In my experience they are due to not doing periodic maintenance.

I took over the largest cast film line in the world (at that time - 1994) and improved the up time to over 95% from less than 80% in under 6 months by simply giving the line to maintenance every 3 months so they could run their checks (vibration, wear, etc.) as well as doing the requisite lubrications and replacements.

Now I will not argue that alignment is important as I have improved the run time on lines I worked on with my consulting customers by having alignments done but this was only with lines that had never be aligned after installation.

C. J. Daly
Yucaipa, California, USA

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