Keeping your CNC spindles machines in top condition is a start
When machine shops experience an issue with their CNC machine tool, issues arise like unexpected repair bills and days or even weeks of downtime. So what are some of the best practices for preventive maintenance of your spindle machine so you can avoid downtime? According to Kip Hanson in an article published in Ctemag.com, here are some of the best practices:
- Kill contamination. No one should be expected to breathe dirty air, and this is just as true for machine tools as for machinists. If a shop’s compressor routinely spits out watery or oily air, rest assured that air will work its way into your machine tool’s critical components, including air-purged spindle bearings. Keep the water trap on the machine’s compressed air regulator clean. If it has an oil reservoir attached (most do), check it daily. Remember that air compressors also need routine maintenance.
- Ease into it. Any automaker would advise against taking a new sports car to a racetrack or pulling stumps with a new pickup without first “breaking it in.” Machine tool spindles are no different. Always follow the manufacturer’s recommendations on spindle startup. Even veteran machine tools should be given a chance to ease into production, especially after a long weekend. After turning on the machine, bring up the spindle to a couple of thousand rpm, grab a cup of coffee and spend a few minutes planning your day while the machine warms up.
- Use the force. When the Belleville washers found in most machining center drawbars fatigue, their grip on toolholders within the spindle taper becomes less secure. Microscopic holder movement ensues, hurting part quality and tool life and most likely damaging the spindle and toolholders as well. The solution is a drawbar force meter, which allows operators to quickly inspect this often overlooked machine component. Although a meter can cost $1,000 or more, the investment may mean avoiding damage to a spindle that could easily cost 10 times that amount to repair.
- Buy top-grade tooling. A high-quality, well-maintained toolholder is another overlooked component of successful machining. Inspect and clean toolholders and the spindle every day. If toolholder tapers have fretting, chip marks or rust, replace them. Use high-quality retention knobs; recognize that they and the toolholders have a life span of roughly 6,000 hours under normal use. Balance all toolholder assemblies that operate at 8,000 rpm or higher. Finally, minimize the radial cutting forces and amount of tool overhang—applying a cutter that’s sticking out 10 diameters deep to hog a deep pocket is asking for trouble.
- Don’t wait. Repairing spindles sooner rather than later means avoiding the catastrophic damage that occurs when bearings seize. Instead of performing a simple, less expensive rebuild at a time of your choosing, the spindle will need to be shipped in the quickest possible manner. The spindle builder will likely charge expedited fees for services. Shafts will need to be reground or even replaced, as will damaged spindle housings and other components, further increasing repair time and costs.
If you have the technical equipment and staff to properly and safely repair your spindles in house, go for it! The disassembly process can be extremely dangerous so do not proceed if you are not qualified to do so. Feel free to reach out to the Motor City Spindle Repair team to ask questions and we will do our best to assist you throughout the process.
We rebuild precision CNC spindles in our facility, but are here to support you. If you decide to attempt the repair process yourself, please consider the following:
Will you need assistance with purchasing the additional spindle components?
If so, we can supply them.
Will you need to have spindle components reworked or re-qualified? This can include motor rewinds, drawbar parts, spindle tapers reground, spindle shaft bearing journals, sensors, encoders, rotary unions, etc.
Motor City Spindle can supply these parts to you for less than the OEMs pricing. After all, we are the CNC spindle repair experts!
Interested in speaking with a team member?
Click here to fill out our free spindle repair estimate form
