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Spindle orientation troubleshooting on older fanuc controls

Spindle orientation troubleshooting on fanuc 15 control.

This particular spindle orientation problem occured on an old Hitachi VK series machine. When a command for spindle orient was given, the spindle would rotate only, never stop or even attempt to stop or decel. The spindle would start up and continue to rotate at around 300 to 500 RPM. This particular machine didn't have the tool changer working for many years which was the main reason for the service call. They wanted to get the tool changer fully functional once again. After playing with the adjustment pots on the spindle orient board for awhile I could make no changes other then slowing the rpm down.

Typically when the spindle just keeps turning with no hesitation, this generally means there is a problem with the sensor or reading the sensor ring or the preamp.

To start to troubleshoot I removed the sensor from the sensor ring and tried an M19 for spindle orient. The spindle reacted exactly the same. After further inspection of the sensor I found the sensor head was cracked at the flange. My guess to how it was damaged was that someone had taken off the unclamp cylinder in the past and forgot to remove the sensor and wacked it when they reassembled. They service person probably did not test the oriention function since it was not being used at the time for the tool changer.

After ordering a new sensor and preamp and installing the spindle began to orient properly.

After I verified the basic orientation command was working ok I adjusted the spindle orient to the proper position for tool change.

Next step was to test a tool change in MDI. After pressing cycle start the tool change did not complete or even start. It grabbed the tool from the magazine and sat there and waited eventually alarming out. What I had to do next was adjust another pot on the orient board for the inposition LED to light up. After this adjustment the tool change was fully functional and the machine ran great.

Hope this helps you in the way of troubleshooting spindle orientation problems on older fanuc controls. Any comments or other recommendations to help others please post below.