Although we have many excellent blogs on the cause of non-repeatability, or more commonly known as frustration when attempting a precision shaft alignment, this issue continues to come up nearly every training session I conduct.
And the number one cause? Not controlling backlash or looseness. All the trainers teach this and VibrAlign has a very good training video that demonstrates an excellent method of controlling backlash or looseness in a coupling. https://youtu.be/AnNfrW7EqCk
I conducted training recently where a competitor’s laser was brought into the class. They were told that backlash had no adverse effect when using this laser. Well guess what, without controlling the backlash in the coupling, that laser would not give repeatable results either!
Here are a couple more examples that I have witnessed during the field portion of our training.
At one location we had two groups performing precision shaft alignments on two different pumps simultaneously. One group just couldn’t seem to get repeatable results. The cause? They simply forgot to tighten the chain brackets, therefore looseness was the culprit.
At another location, similar scenario, except this incident was caused by loose sensor posts in the mounting fixtures. Again, looseness was the culprit.
Are you getting frustrated or having repeatability issues? This might be a good place to examine.