Intervention is Key to Machine Life Extension

Jim Fitch, Noria Corporation
Tags: industrial lubricants

Try this simple experiment. With notepad in hand, go out into your plant and walk around a sampling of your most critical machines. These are the ones that have high probability of failure and/or the greatest consequences of failure. They are also known as show-stoppers and, as such, generally merit a disproportionate allocation of reliability and maintenance resources.

Next, on your notepad make a list of all the lubrication-related enhancements that have been implemented on these same machines since they were commissioned. Take special note of those that have been applied in the past five years. Solicit any amount of help (from old-timers, for instance) you need to flesh out your list.


Figure 1. Remaining Useful Life

The Sad Face of Status Quo
Next, arrange your change-list items into the following groups:

The Quality of Lubricants. Consider ways in which you have optimized the specification of: viscosity at operating temperature, minimum viscosity index, NLGI number, thickener type, additive requirements, base oil type and in-service performance (oxidation, corrosion control, air suppression, water-handling ability, film strength, deposition control, etc.). Note, use of generic OEM or service manual recommendations does not qualify as an enhancement.

The Quality of Lubrication. Consider ways in which you have optimized the deployment of: lubricant delivery/application methods, lubricant change or relubrication interval, determination of lubricant volume, and consistency of lubrication procedures (documented procedures and training are in place). Again, standard methods that came original with the equipment do not qualify.

Contamination Control. Assess enhanced contamination control features and practices that are in use, such as improved filters, breathers, seals, headspace management, etc. The key word here is "enhanced".

Oil Analysis, PMs and Inspection. How has lubrication condition monitoring advanced? Consider such improvements as: new or retrofitted live-zone sample ports, level gauges and sight glasses, quality sampling hardware and procedures, aggressive alarms and limits, on-site and laboratory routine testing and selected test slate, testing frequency, data interpretation strategy, response to nonconforming conditions, inspection (tools, frequency and skills). Again, what you want to note is how each of these areas have been improved and/or applied with greater precision.

Now with your list complete and items grouped, fit each of your critical machines into one of the following categories:

Stuck-in-a-Rut. With this machine, nothing really has changed or been improved. We're doing things pretty much the way we always have. It seems we accept wear and failure as normal. Management has an agnostic view of the benefits of change.

Discontinuous Improvement. Change and improvement have been moderate or intermittent for this machine. We've tried some initiatives in the past but many of these ideas lost support. We've since drifted back to our old ways. Only a few enhancements remain.

Quick-change Artist. With this machine, we have taken an aggressive and innovative approach to reliability and lubrication. We've applied numerous measures to raise the bar. We've discarded the ideas that didn't work and moved on to those that did.

If your machines are like those we most commonly see in our lubrication audits, regardless of their criticality, most will fall within the stuck-in-a-rut or discontinuous improvement categories. View this as low-hanging fruit.

Unconventional Wisdom
Being a reformist and bucking convention is never easy, whether it's in lubrication or any other field. Intervention is usually met with resistance, at least at first. Take a look at the remaining useful life (RUL) graph (Figure 1). On the y-axis is the common RUL scale from zero to 100 percent. Naturally, a new machine has an RUL of 100 percent.

The x-axis is time or machine service life, say in hours. For discussion purposes, I'm showing three approaches to maintenance for a high-duty hypothetical machine. Typical "textbook" maintenance for this machine would give an 8,000-hour operating life if it was taken out of service at 20 percent RUL (80 percent of its life is consumed). This is the center, left-to-right diagonal line on the graph.

Substandard or neglected maintenance would yield a steeper curve of just 5,000 hours of service life. Applying an intervention approach to maintenance is the only way to flatten the failure-development curve to deliver a marked life extension (14,000 hours). Intervention is an aspiration-based strategy that requires change to occur before an impending failure condition exists. Convincing management to fix a machine that isn't yet broken is always a daunting task. Have your facts and data in hand.

With change comes risk, so don't be an innovation maniac. Do your homework and get lots of advice from those who have traveled these roads before. And at the point where the risk is the greatest, have solid contingency plans. Then execute and make the needed adjustments to refine your strategy.