Laser Alignment

The Importance of Laser Alignment

It's estimated that 50 to 70 percent of vibration issues in rotating machinery are caused by misalignment, according to Texas A&M's OAKTrust study on coupling misalignment forces. In fact, reliability equipment supplier VibrAlign reported that one of its customers found that just over half of their plant's machinery was misaligned to some degree. So, why is shaft alignment a big deal?

While misalignment has no quantifiable effect on motor efficiency, correct alignment does ensure you have a smooth and efficient transmission of power from the motor to the driven equipment, according to research on motor shaft misalignment by the University of Tennessee's Maintenance and Reliability Center (MRC). Misalignment creates excessive vibration and high loads on bearings, mechanical seals, packing and couplings, impacting the operating life of rotating equipment. Other effects of misalignment are:

• Lost production
• More frequent repair orders
• Increase in spare parts purchases
• Low-quality products

Modern laser alignment tools check for three types of misalignment: parallel (offset), angular and a combination of the two. Both of the two main types (parallel and angular) can occur in vertical and horizontal planes.

 

1.  Parallel (offset) misalignment occurs when the centerlines of the two shafts are parallel but not in the same line. Shafts may be offset horizontally, meaning they're offset to the left or right; or offset vertically, meaning they're positioned at different heights.
2. Angular misalignment occurs when the motor is offset at an angle in relation to the driven equipment. For example, if you were to draw an imaginary line from the centerline of the motor shaft and the centerline of the driven equipment shaft, the two lines would eventually cross rather than run along a common centerline. Angular misalignment can be horizontally or vertically misaligned. This type of misalignment can cause measurable damage to both the motor and driven equipment shafts over time.
3. Combination misalignment is a combination of misalignment types that occurs when the motor shaft incurs both angular and parallel misalignment.