VibrAlign Fixturlaser Go, Руководство по обучению

Страница: 7 / 40

Pre-alignment checks and corrections are performed to either
improve machinery reliability or to facilitate the alignment
process. In either case, pre-alignment is a very important
phase of the alignment process.
The pre-alignment process could include all of the following
checks: (1) Clean up around and under machinery feet. (2)
Consolidation of small shims with fewer thicker pieces. (3)
Checking run out. (4) Checking pipe strain. (5) Performing a
lift check to check bearing clearances. (6) Rough alignment. (7)
Checking hub separation on spacer couplings. (8) Recording
and tightening bolts in a known sequence. (9) Checking final
soft foot.
We will limit the scope of this chapter to what we term “the pre-
alignment essentials.” You will demonstrate understanding of
the following terms and procedures: rough alignment, correct
obvious soft foot, tightening bolts in a known sequence, and
correcting final soft foot.
ROUGH ALIGNMENT
Rough alignment is performed to expedite the precision
alignment process. It is intended to
quickly
get the machines
“in the ball park.” On close-coupled machines (those with no
spacer coupling), rough alignment can be performed with a
scale or any straight edge to remove vertical and horizontal
offset misalignment. On machines with spacer couplings,
we recommend that you correct both the angular and offset
misalignment vertically and then the angular and offset
misalignment horizontally.
Using a scale or straight edge, correct rough vertical
misalignment by referencing the highest hub. Place scale
firmly on the highest hub and raise or lower the movable shaft
to within 20 mils (0.020") of the stationary hub.
Using a scale or straight edge, correct rough horizontal
misalignment by referencing the hub closest to you. Place
scale firmly on the hub and adjust the movable shaft to within
20 mils (0.020") of the stationary hub.
OBVIOUS SOFT FOOT
Soft foot occurs when the machine feet do not rest flatly on
the machine base. Soft foot is caused by deformed machine
base plates or by deformed machine feet. In either case, the
effect when tightening the bolts is that the bearings become
misaligned, bearing clearances change and the machine
P R E - A L I G N M E N T C O N S I D E R A T I O N S
4