If your spindle performance has been less than optimal lately, it can halt your machine shop’s operation. Fully functional spindles are essential for the most efficient performance. It’s time to troubleshoot your spindle if it’s failing to work properly so you can determine if you need a spindle replacement or repair. Here is an overview of some common problems that are experienced with spindles, as well as information on how to proceed if it describes the problem you’re experiencing.
Sensors failing to work properly
You need to determine the root cause of the problem before attempting to make any adjustments to the sensors. Ensure that the sensor logic is accurate and working properly. You should also:
- Inspect the tool clamp/unclamp valve to ensure it’s not leaking
- Make certain that the spindle is receiving adequate air pressure
- Check for any broken clamps
- Ensure that your pull studs are the correct size
- Inspect the machine’s offsets for each axis
- Attempt to adjust the drawbar. If you’re not successful, you may need to replace the sensor
Air is seeping out of the front of the spindle
Most spindles have built-in safety functions to minimize the chances of pollution. So, air coming from the front of your spindle is normal and shouldn’t be a cause for concern.
Spindle is overheating
Your spindle has several cooling mechanisms that should prevent it from overheating: an internal fan, coolant, and compressed air. You need to check to see if they’re all working properly. You should also keep an eye on the draw during the cut, as a higher-than-normal cut rate can indicate an excessive feed rate or a dull tool.
Spindle is Noisy
If your spindle is noisy when rotated by hand, you could have a bearing problem that needs to be checked out by the manufacturer.
The spindle is running backwards
If your spindle is running backwards, it’s an easy fix that is common with spindles with 3-phase motors. Simply switch any two power leads, and the spindle should run in the correct direction.
The spindle is completely locked up after previously running fine
First, check the solenoid that controls the spindle clamp/unclamp for leaks. If you determine that there is a leak, vital parts may have been welded together. This requires the spindle to be disassembled for repair, so you will need to contact your spindle’s manufacturer. Technicians will disassemble, diagnose, and repair the spindle before returning it to you.
The spindle fails to rotate
Will the spindle rotate by hand? If it turns easily, then you can continue using it. If it still fails to rotate, the bearings may have sustained some damage, or it may have been actuated while running. Attempt to turn the spindle by hand. Is the sensor logic working properly and reading accurately? Is the clamp/unclamp leaking? Contact your manufacturer, who will likely have you send the spindle in for diagnosis and repair.
Spindle hovers over tools but fails to grasp it
This is often caused by the “tool open” sensor malfunctioning. You will need to ensure that the injection stroke is working properly before attempting to reset the sensor.
The spindle is vibrating violently and functioning in an inefficient manner
A problem of single phasing could cause this. Check the connections in the spindle, VFD, and any connectors. If this is unsuccessful, it will be necessary to have an expert diagnose and repair the spindle.
Clamping fingers breaking on tool changer
First, you should check the machine offsets for each axis. Also, determine the timing of your tool-change routine.
HSK Spindle fails to release the tool
If your HSK spindle fails to release the tool, you must first ensure the spindle has adequate air pressure and that the sensor logic is functioning properly. The “Tool Open” sensor failing to read properly is usually the cause of the spindle not releasing the tool. Regularly applying Lusin G31, a rust inhibitor, could prevent this problem from occurring in the future.
If your spindle is an ISO or CAT Taper and won’t release the tool, it works slightly differently than the HSK. Just like with the HSK spindle, you should ensure the spindle has adequate air pressure. You should also ensure that the sensor logic “Tool Open” sensor is reading accurately. If not, your drawbar assembly may be at fault and may be either bent or malfunctioning.
Spindle has crashed
A crashed spindle usually results from operator error due to the input of improper programming codes. By reentering the correct programming codes, your problem should be fixed. However, spindles can sustain damage during crashes, even if the crash is minor. Carefully inspect your spindle for damage following the crash. If it appears fine but fails to function properly following the crash, you may need to send it to your manufacturer for a diagnosis and repair.
The spindle is unable to dress the grinding wheel
A spindle that is unable to dress the grinding wheel indicates possible failure. Some other symptoms of spindle failure include:
- Excessive vibration during operation
- A poor finish or chatter marks are present on processed materials
- Producing an inappropriate roundness of the part, taper, or profile size
- Strange noises coming from the spindle during operation
- Spindle is hotter than normal to the touch
If you notice any of these issues or anything else strange, it’s recommended that you contact your manufacturer, as your spindle will need to be diagnosed and possibly repaired. You could even need a spindle replacement if repair is not possible.
As you can see, there are several different problems that your spindle could be experiencing. Suppose your problem isn’t on this list, or you continue to experience the issue even after troubleshooting and attempting to fix it. In that case, it’s recommended that you contact your spindle’s manufacturer for further instruction. You will likely need a spindle replacement or repair.
