Detection vs. Correction The amount of Soft Foot detected does not equate to the required Soft Foot correction!
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.)
Some Types of Soft FootRocking 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.
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.
Diagnostic ProcessNumber inside circle Number in parenthesesrepresents a laser soft represents a shimmingfoot 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.
Rocking Soft FootImagine this condition on your machine. The front right foot is short. If youtighten 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 footoff, or distort the rest of the machine frame. If the foot does not break off...
Rocking Soft FootSuppose the short foot is now tight to the base. The frame is distorted andunder stress. How will that stress relieve itself as you loosen each of theanchor bolts in turn, always with the others tight? Obviously, the short footwill come up as fast and as much as you allow it to, if you loosen its bolt.
Rocking Soft FootOn the other hand, if the short foot is tight, the opposite corner (the backleft 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 willlook like, if you loosen these feet...
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.
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.
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.