- Hi, I'm James Otremba, Technical Trainer for Acoem USA.
I've been in equipment reliability and maintenance
for the past 16 years, and today,
I'm gonna teach you the four steps of pre-alignment.
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Following the steps of roughing in,
correcting obvious soft foot,
following a bolt tightening sequence,
and performing a final soft foot check,
lay the groundwork for a successful
precision shaft alignment,
and should be performed every time, regardless,
of what tool you're using.
In order to complete these steps
we're gonna need some tools.
These include: shims of various sizes,
feeler gauge, wrenches for tightening and loosening
the hold down bolts, and a straight edge.
Now let's get 'er done.
The first step of pre-alignment
is the rough in or rough alignment.
By getting the machine close to its final position,
our soft foot corrections will be far more effective.
Roughing in also reduces coupling strain
that can have an effect
on our laser shaft alignment readings.
Typically, we would use a straight edge for this step,
but because it won't fit, we're gonna use a shim.
Lay the shim across the top of the coupling,
and using either feeler gauges or shims,
determine the thickness or width of the gap.
See, this one drags just slightly,
so what we're gonna do
is put a 20 mil shim under each foot.
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With that done, we move to the horizontal offset.
Hold your straight edge to the coupling
and move the motor by hand or with adjustment bolts
until it is close horizontally.
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Obvious soft foot is when all four feet
are not sitting in a common plate.
If you don't correct for soft foot,
the movable machine will come to rest
in a different position each time you loosen
or tighten the hold down bolts.
Ensuring the weight distribution is equal on all four feet
is as simple as nudging each shim
while the hold down bolts are loose.
This is tight, this is tight, this is tight,
and this one's very loose.
Add shims of appropriate thickness to make the correction.
Now a quick check
to make sure that we've fixed the obvious soft foot.
Good. Good. Good and Good.
Next, we're gonna tighten the bolts down.
Our goal here is repeatability.
So when we tighten the bolts down
it's recommended to use a cross torquing pattern
and to tighten the bolts in at least three passes.
Hand tight, snug with a wrench,
and then tighten to final torque.
Begin with any bolt as bolt number one.
Then diagonally to bolt two, long way to bolt three
and back diagonal to bolt number four.
On machines with small motors, or flexible bases,
you may need to use more than three passes
in order to control unattended movement.
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Now that all the bolts are tight
and knowing that soft foot is the problem that it is,
we're gonna perform a final soft foot check.
For this step, we'll loosen one bolt at a time
and try inserting a two mil shim in several locations
around the base of the foot.
If nothing will go under, you know that the weight
is evenly distributed on all four feet.
On larger motors,
you may want to use a dial indicator for this step.
Now that we have the machine rough aligned.
We've corrected our obvious soft foot,
we're following a bolt tightening sequence,
and we've performed a final soft foot check,
we shouldn't have any unintended movement
during the more precise steps
of our laser shaft alignment process.
There are some additional pre-alignment steps
that are recommended before performing
a precision shaft alignment.
This includes: cleaning the machine feet and base,
consolidating shim packs,
checking for runout on the coupling and shaft,
checking pipe strain, bearing clearances,
and hub separation on spacer couplings.
Follow us online for more videos
on shaft alignment and so much more.
I'm James Otremba. Thank you.
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