The document discusses soft foot diagnosis and correction using laser alignment tools. It describes different types of soft foot issues like rocking, angled, and induced soft foot. Rocking soft foot has higher values at diagonally opposed corners. The document shows an example of diagnosing and correcting a rocking soft foot issue using laser measurement values and suggested shim corrections. It emphasizes that the type of soft foot must be correctly identified to determine the proper correction method. Laser tools can accurately detect and diagnose soft foot issues to expedite the correction process.

1. Soft Foot Diagnosis
&
The Soft Foot Wizard

2. Detection vs. Correction
The amount of Soft Foot detected
does not equate
to the required Soft Foot correction!

3. Some Types of Soft Foot
 Rocking (Highest values diagonally
opposed.)
 Angled (Bent foot; bowed baseplate,
angled soleplate.)
 Squishy (Too many shims, dirt, etc.)
 Induced (External forces:
Pipe strain.)

4. Some Types of Soft Foot
Rocking Soft Foot (highest values diagonally opposed)
Three types:
 Short foot rocking soft foot:
 Parallel airgap under foot with largest soft foot reading.
 Tapered airgap (inwards) under diagonally opposite foot.
 Even Rocking soft foot:
 Inward tapers under both diagonally opposite soft feet.
 High Foot rocking soft foot:
 Outward tapers under both diagonally opposite soft feet.
 Larger soft foot value on foot nearest the high foot.

5. Soft Foot Diagnosis
 The type of soft foot can usually be determined by comparing
the measured values.
 Different types of Soft Foot yield different combinations of
values.
 Diagnosis and correction is expedited by recognizing the type
of soft foot problem, then seeking appropriate additional data
required to solve it.

6. Diagnostic Process
Number inside circle Number in parentheses
represents a laser soft represents a shimming
foot reading. correction to make.
20 (Step Shim)
25 25
3 12
0 0
Numbers in the
8 8 corners of each foot
6 10 represent feeler
16 16 gauge value of the
air gap measured.
Arrow represents direction
of taper of airgap, from
highest to lowest.

7. Rocking Soft Foot
Imagine this condition on your machine. The front right foot is short. If you
tighten the anchor bolt, the foot will bend until it can’t bend any more.
Then, if you continue tightening the anchor bolt, you’ll either break the foot
off, or distort the rest of the machine frame. If the foot does not break off...

8. Rocking Soft Foot
Suppose the short foot is now tight to the base. The frame is distorted and
under stress. How will that stress relieve itself as you loosen each of the
anchor bolts in turn, always with the others tight? Obviously, the short foot
will come up as fast and as much as you allow it to, if you loosen its bolt.

9. Rocking Soft Foot
On the other hand, if the short foot is tight, the opposite corner (the back
left foot) will also come up if you let it. So the machine “rocks” diagonally.
Now imagine for a moment what the air gaps under each of these feet will
look like, if you loosen these feet...

10. Rocking Soft Foot
 Laser system indicates Soft Foot values greater
than 2 mils at diagonally opposite corners.
15
15 15
14 1
15 15
9 12
2 12
12 15

11. Short Foot Rocking Soft Foot
Please view our QuickTime video on rocking soft foot in action...
Available as a separate download from our Learning Center page.

12. Induced Soft Foot
 Laser tools will show soft foot
values on two, three or even all
four feet of the machine. The two
highest values tend to be along
the same side or the same end of
the machine frame.
 The distribution pattern of
the values does not match
any angled soft foot patterns.

13. Induced Soft Foot
 Laser tools will show soft foot
values on two, three or even all
four feet of the machine. The two
If you suspect pipehighest values tend to be along
strain, the
Optalign Smart will let you check the same end of
the same side or
for that and quantify its impact
the machine frame.
on the shaft alignment, so you
can take this information to the
pipe fitters as proof of the
problem...
 The distribution pattern of
the values does not match
any angled soft foot patterns.

14. The Soft Foot
Wizard

15. Laser Alignment Systems
Rotalign Ultra is ideal for
soft foot because:
 It has a high resolution
sensor for accurate detection.
 It will diagnose the problem
and suggest a solution for it.

16. Diagnosis: Example with Laser

17. Example Diagnosis

18. Example Diagnosis:
Rocking Soft Foot found

19. Diagnosing the Solution

20. Diagnosing the Solution

21. Diagnosis & Solution Finished

22. Diagnosing the Solution
 An Angled Soft Foot Problem

23. Diagnosing the Solution
 An Angled Soft Foot Problem, cont.

24. Conclusions
 Soft Foot diagnosis & correction is always a challenge.
 Consistently accurate Soft Foot diagnosis is possible.
 Rotalign® Ultra makes this a breeze!

25. Thank you!