Chris Hetzer, CEO/Partner, Gilman USA
If a spindle on one of your machines fails tomorrow, what's your backup plan? Do you have the time, equipment, and expertise required to rebuild the spindle yourself? You could purchase a new spindle, but often that can take several weeks to a few months to receive. Can you afford to have your machine out of service for that long?
There is another option that many companies are now considering: spindle repair. Refurbishing spindles costs about 40% less than purchasing new, and typically they can be back in service in less than a week. However, not all spindle repair services are the same. While some providers offer spindle service, many don't take the time to fully troubleshoot the entire system to identify the root of the problem that caused the spindle to fail in the first place.
Receiving a comprehensive review of your system is a critical step in not only making the correct spindle repairs, but ensuring those repairs provide optimal performance.
What Is Spindle Service?
The goal of spindle service is to keep companies operating at peak capacity by minimizing any disruption to productivity. Spindles truly are the heart of any machine; when a spindle fails, the machine stops, and when it stops, it's not producing…and that's lost revenue. When time is of the essence, spindle service can quickly repair the spindle, as well as evaluate the entire spindle system, and get your machine operating again.
Causes of Spindle Failure
Many factors can contribute to a spindle failing, but the leading cause is contamination, such as chips or condensation that have found their way into the spindle. Most coolants are water-based, which can lead to rust forming inside the spindle. In addition, a spindle seal can fail over time, leaving an opening for other contaminates to enter.
The humid atmosphere created in many machines, especially closed-type ones, further contributes to contamination. When the spindle is operating, its temperature is hot; when stopped, it begins to cool, causing a "chimney effect" to occur -- all the warm, humid air gets sucked into the spindle and bearings.
It's difficult to predict if or when a spindle is going to fail. Certainly the frequency of the machine's operation, as well as the overall application, can play a role in spindle life. If a machine is operating 24/7 in a vigorous environment, more stress is being applied to the spindle system as opposed to a machine that runs only occasionally.
Bearings have a service life in which they are rated to run for a set amount of time, but the useful life of a bearing varies widely. However, there are some things that you can do to extend the life of the spindle system, while identifying potential trouble before it becomes a full-blown failure.
A New Way of Viewing Spindles
Unfortunately a lot of companies don't look at the spindle system as a routine maintenance item. Rather, they just run the machines until something happens, and only then does the spindle become top of mind.
The first thing you should do is establish a routine maintenance program for your spindle system. When possible, begin to schedule downtime to inspect, clean, and lubricate the system. You should also conduct a vibration analysis on the spindle system and establish a baseline for performance, and test the system at periodic intervals. Vibration can be a telltale sign of trouble, so the more often you can perform vibration analysis on the spindle system to catch a problem in the initial stages the better.
Another aspect of routine maintenance is training employees who are working on the machines to listen for any changes in sound. A spindle system in trouble generally gives off warnings, noted by unusual noises, rattling or grinding sounds. If something just doesn't sound right, it probably isn't, and frontline employees are the first ones who can detect a sign of trouble.
You can also look at the output of parts the machine is producing; if the tolerances are off and not up to specification, the spindle system could be in trouble. Being able to detect a problem in its early stages will prove to be less expensive and minimize your machine's downtime.
Best Option: Spindle Service
If your spindle system does fail, you have three options: repair it yourself, purchase new, or have it serviced. In most cases, the latter is the best option for a number of reasons. A reputable spindle repair provider will not only repair the spindle, but also has the expertise, equipment, and facilities to perform a comprehensive review of the entire system and make the necessary fixes to ensure optimal performance when it's back operating in your plant.
Depending on the type of spindle, service can be performed in just a matter of days. A belt-driven spindle that needs seals and bearings replaced can be serviced and back in operation in a few days, whereas servicing a motorized spindle -- which involves an analysis of the motor, removing moisture, replacing the stator and windings etc. -- is more intensive and can take longer. Here's how the process works:
If your spindle system has failed, you're asked to fill out a return materials authorization form, which essentially is a questionnaire about the spindle -- type, manufacturer, serial number, nature of application, and most important, what you suspect caused the failure. The goal is to give as much information as possible to the repair provider, streamlining the troubleshooting and repair process.
Once the spindle is received, an analysis is performed and the problem identified (at no cost), and a quote is given on the recommended repairs. Upon authorization of the scope of work and quote, service begins on the spindle system. A repaired spindle typically costs about 40% less than a new spindle, and generally comes with warranty.
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), you're better off purchasing new. Often this is the case when the spindle is severely damaged, and the parts and labor needed to repair it approach the cost of a new spindle.
Slide Repair
When the spindle system is getting serviced, attention should also be given to the slides, which can take a beating during normal operation. Slides are relatively simple in design and contain just a few parts, so the process of repairing them isn't terribly complex. However, most people aren't aware that slides can be repaired, and opt to replace them by purchasing new.
This area offers cost savings as slides can be repaired, on average, for about 50% less than the cost of new slides. The problem is many service providers don't have the equipment necessary to make slide repairs, and as such, the service often isn't offered. However, slides that are repaired provide years of service at about half the cost of new.
Damaged slides can affect the performance of the spindle. If a spindle fails, many people may think the problem lies just within the spindle, but the real issue could be with the slides. For example, if the parts aren't being manufactured to specifications, the real problem could be the slides not properly holding position, thus affecting the spindle. Another advantage a reputable service provider brings is the ability to diagnose the problem within the entire spindle system, including the slides.
Cleanliness is the best way to keep your slides operating well. During scheduled routine maintenance on the spindle system, lubricate the slides and brush dirt and debris off the slide covers. It takes very little time to clean the slides, so be sure to include them in your routine maintenance program.
Reputable Suppliers
Having your spindle repaired by a reputable service provider ensures that the complete spindle system is evaluated and serviced -- looking at the whole picture of the spindle system, not just the actual spindle, to correctly identify the cause of the problem. For example, if the spindle is failing every couple of months, the problem may be not with the spindle itself, but rather something else within the system, such as slides that are out of tolerance.
Reputable providers will troubleshoot and recognize such an issue because they have in-house engineers who know how spindle systems are designed, how they operate in various applications, and who have a full understanding of how they work and interact with other equipment.
In addition to a staff of design engineers, reputable service providers also have the equipment and facilities to properly repair spindle systems. Look to see if they have a class 10,000 clean room where they do their servicing. A clean room has tightly controlled air quality standards, preventing contaminants from damaging products manufactured in the facility. A class 10,000 clean room refers to the number of particles measuring 0.5 microns or greater in size that are allowed in the room for each cubic foot of air.
Servicing spindles in a class 10,000 clean room means there's less chance of contaminating the bearings than if they are serviced in a facility that doesn't have a clean room. Many providers have limited resources at their disposal, perhaps only a lathe and grinder, and in such as case the level of service available will be rather basic. Research service providers and be sure to select one that has the expertise, equipment, and facilities needed to service the entire spindle system.
Summary
You can save money by having your spindle system repaired as opposed to purchasing new. But not all repair facilities are the same. For best results, seek a reputable service provider with the qualifications, expertise, equipment, and facilities to repair the spindle system, as well as supporting equipment, such as slides. Having your spindle system repaired will save you time and money, and get your machine up and running quicker than purchasing new - and that's good ROI.
