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December 2018 – EFFICIENT PLANT

The recently released Alignment Standard (ANSI/ASA S2.75-2017) from the American National Standards Institute, Washington (ansi.org) took nearly three years to develop. A committee of alignment experts discussed every aspect from safety procedures to the mathematics involved in defining the new standard. Alan Luedeking, CMRP, CRL, of Ludeca Inc., Miami (ludeca.com) a member of that committee, has been involved in the development of alignment standards for significantly longer than three years.

Luedeking remembers the “old days” well. Back then, personnel simply aligned components to the best of their abilities with straightedges or dial indicators. “Those alignments,” he said, “usually weren’t that good, due to sag, span limitations, obstructions to rotation, or whatever. But you did the best you could, and that was good enough because it was all you could do.”

In 1982, Ludeca introduced the world’s first computerized dial indicator alignment system (from the now-defunct Industrial Maintenance Systems Inc.), followed in 1984 by the world’s first laser-alignment system. With the improved measurement resolution and accuracy afforded by the laser sensor, a more precise definition of what constituted a good alignment became necessary. So, according to Luedeking, after poring through the sparse alignment literature that existed, Ludeca developed tolerance tables for short and spacer couplings, which, for lack of anything better, end users readily accepted. “Over time,” he noted, “these tolerance values came to be accepted as the U.S. industry standard and were adopted as the official tolerance standard by various corporate and government entities, including NASA and the U.S. Navy.”

So what are alignment tolerances, and why are they important? As Luedeking described them, “Tolerances exist because absolute perfection does not. No matter how hard you try and how long you work, you will never get a shaft alignment absolutely perfect.” He offered the following detailed discussion as to why, along with some expert advice on the meaning of the new standard and how it can help you improve your operations. Read the entire article “Alignment Tolerances Carved in Stone”

Check out the Easy-Laser XT Series, the only laser alignment platform on the market today with the new ANSI alignment tolerances built-in giving the user the freedom to choose between traditional tolerances, the new ANSI standards, or custom tolerances of the user’s own choosing.

by Ana Maria Delgado, CRL

A survey conducted by one of the world’s leading rotating equipment service organizations shows that less than 10% of the 160 machines randomly chosen for measurement were found to be aligned within acceptable limits.

Shaft Alignment Tolerances
The above tolerances are for equipment running at 3600 RPM. Statistics courtesy of a UK chemical company.

It is important to align your machines to within specified tolerances and for that LUDECA has included Acceptable and Excellent Shaft Alignment Tolerances within their “Laser Align” mobile application. The application has an interactive Tolerance Table,  where the user can input his own machine RPM and the app will kick back the respective Alignment Tolerances for both short flex and spacer type couplings. It also includes a Thermal Growth Calculator and a Soft Foot Assistant to help the user interpret soft foot values.

by Ana Maria Delgado, CRL

Laser Align AppWe are proud to release a new version of our “Laser Align” mobile application. The app is available in the iTunes Store for both iPhone and iPad; as well as in Google Play for Android. The application now has an interactive Tolerance Table,  where the user can input his own machine RPM and the app will kick back the respective Alignment Tolerances for both short flex and spacer type couplings. It also includes a Thermal Growth Calculator and now has a Soft Foot Assistant to help the user interpret soft foot values.
The app is available everywhere for FREE. Download now.
 

by Adam Stredel CRL

There are several ways of looking at alignment tolerances,  including standard versus vector tolerances, as well as sliding velocity tolerances. The most used are standard tolerances, but which are applied differently for short flex versus spacer couplings. The best laser alignment systems will allow you not only to select tolerance types but also coupling types. For standard tolerances, keep in mind that the vast majority of true flexible couplings (such as gear, grid, elastomer element, or diaphragm type) have two separate flex planes. So do all spacer couplings. The difference between short flex and spool piece, spacer, or jackshaft couplings lies in the distance between these flex planes. Any time the distance between flex planes is greater than the diameter of the working flex plane, you are better off calling it a spacer rather than a short flex, from the perspective of achieving satisfactory alignment. Keep this in mind when selecting coupling type, as it will greatly increase the alignability of the machines, and ease your job in the field. For a deeper understanding of the subtleties involved in these issues, it is recommended to attend an in-depth training course in laser alignment.
 
 

by Ana Maria Delgado, CRL

Tolerances For Shaft AlignmentSome coupling manufacturers will sell couplings claiming that the coupling can take shaft misalignment. While this is true for most flexible couplings, it can be easily misinterpreted. Flexible couplings are designed to withstand, without damage, some shaft misalignment. Sometimes it is perceived that, since the coupling can take the misalignment, the machines can run under this condition without any consequences. When running machinery with significant shaft misalignment, bearing and seal life may decrease immensely, and other damage result. Therefore, for longer machinery life, it is always recommended to have equipment laser aligned to standard industry tolerances for shaft alignment, and not to the looser alignment tolerances allowed by the coupling itself.

by Adam Stredel CRL

July 2010 · IMPO Magazine
“You must be the change you wish to see in the world.” — Mahatma Gandhi
Investing in more efficient process machinery makes good business sense and will help to ensure reduced costs plus a greener plant. However, not all plants can afford to replace their present equipment with newer, more efficient machines. What steps can these plants take to “green up” their business and operate more efficiently? Most plants can vastly improve machine reliability, efficiency, and reduce raw materials conversion costs by simply making improvements in their present machinery. This can be done through precision maintenance practices and defect elimination. A good PdM (predictive maintenance) process will help to achieve these goals.
Read entire article: Save Some Green: Green Up Your Machines

by Ana Maria Delgado, CRL