Many factors can contribute to a spindle failing, but the leading cause is from contamination, such as chips or condensation. The humid atmosphere created in many machines, especially closed-type ones, further contributes to contamination. When the spindle is operating, its temperature is hot, and when the spindle is stopped it begins to cool, causing a “chimney effect” to occur in the spindle and bearings. Most coolants are water-based, which can lead to rust forming inside the spindle. In addition, spindle seals can fail over time, leaving an opening for other contaminates to enter.
Because it is difficult to predict spindle failure, the frequency of the machine’s operation as well as the overall application, can play a role in the life of a spindle. If a machine is operating 24/7 in a vigorous environment, more stress is applied to the spindle system as opposed to a machine running occasionally. To extend the life of the spindle system, identify potential problems before it becomes a full-blown failure.
Spindles truly are the heart of any machine. The goal of spindle service is to keep companies operating at peak capacity by minimizing any disruption to productivity. If machine failure occurs, spindle service can quickly repair the spindle, evaluate the entire system, and get the machine operating again.
Proactive measures for a spindle system include creating a routine maintenance program. When possible, schedule downtime to inspect, clean and lubricate the system. Also, conduct a spindle vibration analysis, establish a baseline for performance, and test the system at periodic intervals. Vibration can be a telltale sign of trouble. Therefore, performing a vibration analysis detects problems in the initial stages.
Proactively train employees to listen for any changes in sound. A spindle in trouble generally gives off warnings, noted by unusual noises, rattling or grinding sounds. Further, examine part pieces the machine completes. If the tolerances are off and not up to specification, the spindle could be in trouble. The ability to detect problems in its early stages will prove less expensive and minimize machine downtime.
If the spindle system does fail, consider three options: repair it yourself, purchase a new system, or have it serviced. In most cases, the latter is the best option. Depending on the type of spindle, service can be performed within days. A belt-driven spindle involving replacing seals and bearings can be serviced and back in operation within a few days. Whereas, motorized spindle service involves motor analysis, removing moisture, replacing the stator and windings, etc. is more intensive and can take longer.
A repaired spindle typically costs about 40% less than a new spindle. While in many instances it makes sense to have your spindle serviced, sometimes it is better to purchase new. A general rule of thumb is once repair costs start approaching the cost of a new spindle (when the cost is less than 25% of a new spindle) it is better to purchase a new one.
Finally, if a spindle fails the real issue could be with the slides. Damaged slides can affect the performance of the spindle. When the spindle system is getting serviced, the process of repairing slides is not complex. Slides are relatively simple in design and contain just a few parts. Instead of replacing them or purchasing new slides, repairing offers cost savings on average about 50% less than the cost of new slides. Cleanliness is the best way to keeping your slides operating well. During scheduled routine maintenance on the spindle system, lubricate the slides and brush dirt and debris off the slide covers.
Filed Under: Assembly, Design World articles