A couple of months ago I had some issues with the spindle on my PCNC1100 running erratically. After leaving the machine on, and warming the electrical cabinet the spindle ran fine for many hours. So I put the problem down to condensation, as the mill is in an unheated garage.
However, last weekend, when 'air cutting' on a new program to check clamp clearances, the spindle started, and then stopped. Next time I ran the program the spindle didn't start at all. The program was a simple one, drilling five holes. A detailed check of the G-code revealed no issues, and the canned cycles looked identical to a previous program that had run without issue. Conclusion, there was a problem with the mill itself.
I ran through the troubleshooting guide in the manual and established that there were no problems with contactors and supply voltages to the VFD. Following on from a previous thread on this forum, implicating the speed control signal to the VFD, things got interesting. If I pushed on the three blue relays on the control PCB I could get the spindle to run, let go and the spindle stopped. Modulate the push force and the spindle speed changed in sympathy. I had already found a bad crimp on one of the wires going into the control board, so I remade that crimp, and those for the speed control wires. Although the spindle now ran most times, pushing on the control board PCB would stop it.
This indicated a problem with the PCB itself. I disconnected all the wires and took the PCB out. Bingo, the solder on one of the connector pins for the speed control signal was dull and pitted, a classic dry joint. Elsewhere on the PCB, but still associated with the speed control signal, there was some evidence of a hair, or similar, having been on the PCB during part of the manufacturing process. I've seen this before, on PCBs I've had manufactured for work, and it can lead to open and intermittent tracks. I repaired both areas and refitted the PCB.
The spindle ran all day yesterday, with regular sequences of 10 spindle on/off cycles and poking the control PCB. The spindle ran flawlessly throughout.
Fingers crossed repairing the control PCB has sorted the problem.
Regards,
Andrew
However, last weekend, when 'air cutting' on a new program to check clamp clearances, the spindle started, and then stopped. Next time I ran the program the spindle didn't start at all. The program was a simple one, drilling five holes. A detailed check of the G-code revealed no issues, and the canned cycles looked identical to a previous program that had run without issue. Conclusion, there was a problem with the mill itself.
I ran through the troubleshooting guide in the manual and established that there were no problems with contactors and supply voltages to the VFD. Following on from a previous thread on this forum, implicating the speed control signal to the VFD, things got interesting. If I pushed on the three blue relays on the control PCB I could get the spindle to run, let go and the spindle stopped. Modulate the push force and the spindle speed changed in sympathy. I had already found a bad crimp on one of the wires going into the control board, so I remade that crimp, and those for the speed control wires. Although the spindle now ran most times, pushing on the control board PCB would stop it.
This indicated a problem with the PCB itself. I disconnected all the wires and took the PCB out. Bingo, the solder on one of the connector pins for the speed control signal was dull and pitted, a classic dry joint. Elsewhere on the PCB, but still associated with the speed control signal, there was some evidence of a hair, or similar, having been on the PCB during part of the manufacturing process. I've seen this before, on PCBs I've had manufactured for work, and it can lead to open and intermittent tracks. I repaired both areas and refitted the PCB.
The spindle ran all day yesterday, with regular sequences of 10 spindle on/off cycles and poking the control PCB. The spindle ran flawlessly throughout.
Fingers crossed repairing the control PCB has sorted the problem.
Regards,
Andrew