Types of CNC Spindle Malfunctions | Epic Tool
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Types of CNC Spindle Malfunctions

cnc spindle

In CNC machining, the spindle is both a strength and weakness. When bearings or other components in a spindle assembly start malfunctioning, it’s time to pause operations and determine what’s happening or else greater disasters could follow. This blog will provide you an outline of various defects, distortions, and complications that can occur when the CNC spindle starts to wear down.

Diagnosing CNC spindle malfunctions

It’s hard to be mindful of every potential issue and how to properly diagnose it and yet, as a CNC operator, that’s exactly what’s required. Troubleshooting problems with CNC spindles can be time consuming but it’s worth every second once you consider what the alternative could be.

A few common CNC spindle issues:

  • Spindle freezes
  • Spindle runs backward
  • VFD keeps tripping off
  • Tool won’t release
  • Tool slippage
  • Spindle jerks and vibrates
  • Low power to tool
  • High temperature
  • Spindle suddenly stops for no apparent reason
  • Air leaks
  • Spindle not releasing
  • Sensor malfunction
  • Radial load failure
  • Clamping malfunction
  • Broken fingers on tool changer
  • Axial load failure
  • Poor tool balance
  • Actuator piston timing failure


Signs a CNC spindle is wearing down

As the CNC tool spindle begins to wear, certain indicators become apparent. A CNC operator should keep their eyes and ears open for these issues. More often than not, it’s the operator’s awareness that catches the machine malfunctioning before a production issue is noticed.

Different signs operators should be aware of during production that can help troubleshoot CNC spindle problems:

  • Unusual vibration: Minor vibrations lead to major ones. A certain amount of vibration is to be expected but when an operator feels an unusual amount of vibration, the machine should be shut down and inspected right away.
  • Strange noise: An odd sound is a great indicator of poor performance and typically if something doesn’t sound right, it usually isn’t working properly. Listening to the CNC machine and noticing a squeak or squeal is not a good thing and should be investigated thoroughly before continuing with production.
  • High temperature: Checking the temperature of the CNC machine is a great way to see if something is off. CNC spindles should operate between cool and warm to the touch. If the temperature exceeds that range, the spindle needs to be serviced for loose bearings or other causes of unwarranted friction.
  • Rough finish: Rough edges, chafing surfaces, and broken workpieces are all signs that a CNC spindle has excessive wear or poor contact with tools and should be corrected immediately before more damage is done to workpieces or the CNC machine.
  • Spindle mouth deterioration: Tools being shoved in and out of a spindle cause wear on the surfaces resulting in poor tool transfer and unstable tool retention.
  • Damage inside tool holders: The tools being inserted and removed can cause internal damage that is difficult to see and diagnose. Thorough inspection by qualified technicians should be done right away if this is suspected.

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