Soft Foot: What Is It and What To Do About It
Of the minor irritations we encounter on a regular basis, few are more irritating than going out to eat and sitting down at a table with one leg ever-so-slightly shorter than the others. Throughout the meal, the table continues to rock — disrupting everyone’s dining experience. It may seem like a relatively minor annoyance at the dinner table, but soft foot has real, costly ramifications in a factory environment.
Left unchecked, soft foot can cause significant misalignments in machinery — resulting in defects, repair costs, unanticipated downtime, or worse, operator injury. The key is to catch — and fix — it early. Know the signs and stay on the lookout.
What is soft foot?
A common problem in rotating machinery, soft foot is a type of machine frame distortion. The four different types of soft foot are parallel, angular, squishy, and external force. Though they have different causes, all cases of soft foot occur when a machine’s foot fails to make adequate contact with its base plate.
The biggest issue with soft foot is that it perpetuates machine vibration. Vibration quickly causes major damage to machines and results in the need for costly repairs. Left unchecked for too long, soft foot leads to a significant increase in maintenance demands.
Manufacturers must be diligent in identifying possible factors contributing to soft foot. Recognizing issues early helps prevent the need for expensive repairs down the line. Some of the chief contributing factors to soft foot include:
- Warped, twisted, or bent machinery feet or baseplates
- Dents or other malformations in a machine’s base or feet
- A collection of dirt, debris, or other contaminants under machinery feet
- Deformed or damaged shims under machinery feet
- Improper leveling or misalignment on the Z-axis of the machine
- An excessive number of shims under one foot
While all these problems can contribute to soft foot, the main cause is frame distortion. Issues associated with frame distortion include misalignment, increased vibration levels, higher levels of corrosion, increased energy use, cracks, distorted seals, and much more. Stay vigilant on these issues as they often correlate to a soft foot problem.
How to fix soft foot and extend equipment life
While it’s not as easy as fixing a wobbly table, there are several simple techniques for correcting soft foot. For example, leveling and shimming machines to reduce vibration can help prevent soft foot. It’s also essential to ensure all base plates are in good condition before installation.
Catching issues associated with soft foot is relatively easy with regular vibration analysis and laser alignment equipment. Smart tools can even offer recommendations for correcting soft foot.
Soft foot is an equipment killer
If not caught early, soft foot will damage and destroy machinery. One of the most significant problems caused by soft foot is increased vibration. Frequent vibration often results in misalignment, which can slow down production and increase maintenance costs. It’s important to regularly check all machines for signs of soft foot, and — at the first sign of vibration or soft foot — take a measured approach to correcting it before the problem gets worse.