Archive for December, 2007

This is NOT a Guessing Game…

Friday, December 28th, 2007

…or at least it shouldn’t be! Vibration analysis corresponds to a science. Of course, the art and science of getting the proper measurement from the pertinent location(s) with adequate instruments before performing knowledgeable signal processing (if needed) also come into play, but the analytical part mostly relies on relatively simple notions or assumptions while reviewing fairly simple data.

We regularly hear about what we would deem failed predictive approaches where a lack of training or a lack of expertise seek dismantling and inspection of machinery components instead of proper analysis leading to an accurate diagnosis of the problem at hand. This approach amounts to bad (and costly) predictive maintenance management. It also favors extraneous manipulation of machine components best left alone when considering the potential human-error factor linked to intrusion (equivalent to resetting the bathtub or other curve to the infant mortality phase). Precision maintenance mitigates the previous factor, but then, it is a rare case indeed to see precision practices in a context where condition-monitoring fails to go hand-in-hand with proper diagnostics.

© 2007 by François Gagnon

Vibration “Problems”

Friday, December 28th, 2007

Confusion reigns with respect to machinery vibration issues. Most people still hang on to vibration as a problem, instead of the diagnostic science of vibration as an indication of a developing problem.

Where does the difference lie? Vibration as a problem per say falls more in the AMPLITUDE analysis category, and remains blatantly obvious in most cases. Excessive vibration levels can be directly linked to unbalance, severe misalignment, resonance (or rotor critical speed problems) and other perceptibly notable behaviors, such as what might be exhibited by a machine or component having failed or well-advanced in its failure mode. Vibration as an indication of a problem tends to be a FREQUENCY (or time waveform contents) analysis issue. Of course, the appearance or growth of a small peak may bring us back into an amplitude context, and small amplitudes often show severe problems. Our vibration measurement will reveal anomalies or abnormalities that could yield catastrophes. The apparent insignificance of some amplitudes may well be linked to the location of the problem relative to measurement point, slow speeds, difficultly transmitted phenomena (ex: an incipient inner race problem must send the vibration wave through two thicknesses of lubricating fluid, above and below the rotating element which must also be traversed to then transmit to the outer race and subsequently, the pillow block: a long trajectory for a tiny peak lost amidst other events and noise) and other barriers to our perception. We’ll remind the reader that we advocate learning to look at data both in linear and logarithmic scales to familiarize and sharpen the analytical sense when interpreting more difficult or “veiled” problems.

The seasoned analysis veteran likely knew all of the above. But the newcomer or the merely distant onlooker (receiving reports as opposed to performing predictive tasks) may now realize that vibration is not just about crankshaft-like motion.

© 2007 by François Gagnon

Change? Or Upheaval?

Thursday, December 13th, 2007

We often hear the words “change management” as an adjunct to reliability efforts. Yet, if one is to trust reports of reliability effort failures and abandonment, or reversal / devolution to earlier methods (or lack thereof), something must surely be going awry in the way we attempt to do things.

Change can be good, and it is inevitable, but too much change at the same time overwhelms personnel. A new approach to data input into the CMMS or EAM requires training and a little time for old (and usually inadequate) habits to get reformed. If management simultaneously modifies a whole list of other things, the chance of success in implementation suffers a considerable negative impact.

We are all too aware of the existence of resistance to change. “Better” must be demonstrated and proven before wholehearted adoption can take place. And criticism along the way will likely occur. The arguments of “bad faith” and “you’re resisting the change” usually point to bad implementation (key word would be usually: some people will just reject anything new out of hand).

 As an example, I am reminded some 15 years back of the arrival of a software package for vibration-based condition monitoring. One of the (or perhaps just “the”) first operating on a Windows platform. It was pretty. It was easy to use. But its failings lay entirely in technical contents (or lack thereof): you could not do (at release) what had been common fare with the DOS version. As a matter of fact, I’m not entirely sure the final version could either, but that’s another story. Comments with respect the technical deficiencies or missing functions brought annoyed replies implying “resistance to change”. Was that the case? The passage to Windows and its GUI were good, no doubt. An SQL database was also a much needed improvement. The price to pay was high: the loss of technical contents needed to properly assist the analyst proved contentious for a long time.

The problems encountered while managing change often arise from a lack of understanding (or even caring) of the needs of all parties involved in the execution of the mission (production, maintenance, other). Things work out better when all parties are consulted BEFORE an initiative launches, and that means all parties at all locations of an organization (the needs, or the level of change, may differ considerably). When scepticism arises or when questions are asked, one needs to confront them head on, with pertinent answers.

Bottom line: enthusiasm and the embrace of movelty may be formidable drivers, but if the homework has not been done to convince others, support their needs and address their concerns, reliability (and other) initiatives may fail, with regressions, dismal results (in ROI terms), or simple failure to launch properly.

© 2007 by François Gagnon