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Feedrate Override Knob problem

poxino

Aluminum
Joined
Jan 11, 2017
Hello there!
I am having an odd Issue with the feedrate knob on my machine.

Control if Fanuc 16mb , the machine is quite old , but it has been reliable so far.

I am not sure if I had this problem in the past , however I certainly noticed today.

When knob is set at 80% , feedrate is 0 (machine doesn't move) , when the knob is set to 130% machine seems to move at 50% of the programmed feed rate.
The 100% is still working correctly.
Is this just a bad rotary switch, or something major?
There are no alarms of any sort at the moment.
 
If you are lucky, the problem is dirty switch contacts. Open the control panel and look at the backside of the switch. Pretty sure those are an open switch and not enclosed. Cleaning the contacts should be a pretty easy task with some contact cleaner. If that does not work- go to the diagnostic page in the control, locate the feed rate override bits and see if they change when you rotate the switch. You can find the I/O addresses in the wiring schematic for the machine. Hopefully you have that.
 
A lot of machines have parameters tied to the feed override settings. Could some joker messed with them?
 
Hello there,

thanks for the many replies, this is such a good forum!

I will try to clean it , if not I will send an RFQ to Fanuc and see what the cost is for the new part.

Would you then think this is rotary switch related issue only?
 
......I will try to clean it , if not I will send an RFQ to Fanuc and see what the cost is for the new part.......

The feed override rotary switch is a machine builder provided item. Not Fanuc supplied unless the machine is a Robodrill. You will need to contact the machine builder for a replacement or source an equivalent through an electronic parts supplier.
 
The feed override rotary switch is a machine builder provided item. Not Fanuc supplied unless the machine is a Robodrill. You will need to contact the machine builder for a replacement or source an equivalent through an electronic parts supplier.

You guessed it right, as usual, the machine is a Robodrill, I found the part number on the parts manual.
 
Hello guys,

you probably knew from the beginning, I just wanted to confirm for someone else with the same problem.

I bought some electrical contact cleaner, and that's it this was the solution , after the cleaning the rotary switch works as it should be, it physically feels better as well.

Thank you all!
 
Hello there,

After cleaning it , the rotary switch worked for about 1 day , then same problems again.

I ordered the part, which arrived yesterday , but it does not look like is a plug and play installation , there seem to be some soldering involved...

Any help?
 








 
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