You’ve heard the adage “look before you leap.” Do you also look before you align? When conducting rotating shaft centerline alignment, it’s imperative that you perform proper preliminary steps. Even though laser alignment systems are taking the place of traditional alignment practices, it is vital to adhere to best practices before and during the alignment process.
I often hear maintenance mechanics and millwrights use the phrase “coupling alignment,” but this is actually a misnomer. “Rotating equipment shaft centerline alignment” is a mouthful, but it’s a more-precise description. The centerlines of the two pieces of rotating equipment must be made collinear.
Laser systems alone do not magically ensure that machine centerlines will be collinear. The technician still has to make the moves. Think of old-school compass orienteering – someone has to do the legwork. Even with modern GPS, which tells you where you are and how to get where you want to go, you still have to take action to get there. And along the way, some hills and valleys need to be considered.
It is also important to understand that flexible shaft couplings allow for some misalignment, depending on the type, but they have limits, as well. Moment loads and forces don’t disappear; rather, they show up in the form of heat or result in distortion in the machine’s components.
