Lack of Repeatability using a laser alignment system

May 13, 2009

When experiencing lack of repeatability using a laser shaft alignment system:

Check the components for looseness.

Brackets: Make sure that they are rigidly attached to the shafts (or solid coupling hubs). The surface imperfection where the brackets are mounted plays no role provided the shafts are rotated and the bracket is firmly attached to the surface.

Risers: Most brackets systems will have risers (support posts) attached to them to mount components. Make sure they are firmly attached to the brackets.

Lasers, Receivers, Prisms: Also make sure they are firmly attached to the risers.

Brackets rubbing: The brackets and everything they support must not touch or rub on any stationary part during rotation.

Looking out for these simple little things can save you many headaches during your alignment job.

Tip provided by LUDECA, INC.
ALIGNMENT * VIBRATION * BALANCING
www.ludeca.com
Tel: 305-591-8935

Find out more about LUDECA Shaft Alignment Systems
http://www.ludeca.com/prod_optaligsmart.php

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Comments (2)

Firstly if you want realistic repeatability you must ensure that there are no soft feet and that all holding down bolts are correctly torqued down.
1) Posted 12:03 pm, 14 May 2009 by John Drummond
Valid Point! Softfeet can make getting the shaft alignment in tolerance at the coupling very difficult. That is one of several effects of softfeet. However any alignment method done with the coupling connected changes things here. If there is a significant amount of offset (vert. or Horiz.), it will distort the softfeet readings. Therefore, 2 softfeet readings should be done: The first is before connecting the coupling. Place one shim (all the exact value) under each foot. Can you wiggle or move any of the shims? If so, shim up to get out the majors.

Set up your laser or (Reverse Dial), then make the first moves. THEN check the softfeet when the alignment is NEAR the aligned condition. Have you ever had to put more shims under the back feet than the front feet, or more under the front than the back to achieve alignment? If so, you may have created angled softfeet. If you ignore measuring sofeet when it is near the aligned condition, you may not be in spec for the softfeet.
2) Posted 6:46 pm, 21 May 2009 by Roy Loop