Hi all, I was drilling a piece of mild steel with a brand new 1/2” bit. I was peck drilling at 3500rpm and 1.5 in/min. Very conservative in my opinion. I drilled about an inch or so, the spindle then stalled. I was quick on the stop button. I retracted the bit, rehomed the machine just incase, and tried to rerun the sequence to finish the hole. The spindle wound not turn back on. I checked incoming power, fuse, breaker, verified voltage. I checked the drive belt. The motor is not locked up. I checked the connections for the spindle motor on both ends? Everything on the software side seems to be working fine.
is my spindle shot? It’s not hot, not even warm. It makes no sounds at all; not even a hum. Is there something I am not thinking to check?
Did you power cycle? The servo will error out in a stall and needs to be reset when that occurs.
What kind of drill were you using? 3500rpm sounds plausible for carbide but would be extremely fast for more common CoHS (Cobalt) or HSS drills.
Edit: I checked on FSWizard and for 1/2” carbide drill they recommend 1780rpm at higher feed rates to get a good chip. It looks like your setting would result in a chip thickness of about 0.0002 (2 tenths), which is going to rub the edge of the tool and wear it out quickly.
Personally I would interpolate holes 3/8” and larger using a 1/4” or 3/8” carbide endmill. It saves a tool change and the helical bore is a lot less load on the mill than a 1/2” drill.
I’ll check my program again maybe I’m mis-remembering my speeds, I’m using a cobalt bit, i didn’t measure the ribbon but it made a nice ribbon rather than chips/shavings. Everything looked normal or what I expected to see; that is until the spindle stalled.
Unfortunately not yet, but I did speak with technical support today and when I get back home to the machine, I have some more in-depth troubleshooting to work on.