Hi there, My Longmill MKII has recently started to randomly stop during a carve. Here’s what I have tried so far:
Tried several different projects, with different wood, different cutters, different gcode files.
Replaced the Z motor and wiring for new (a while ago I managed to burnout one of the connectors so purchased a new motor and also ordered the 48″ extension kit which included the new lead)
Undated gcode and Vectric to ensure I have the latest versions. I also ran a windows update – just in case!!!
Disconnected and reconnected all cables several times.
Restarted the computer several times.
Disconnected all appliances on the same electrical circuit. I still have a heater plugged in (my shop is cold) but this is on a separate 240v circuit / breaker.
Progressively reduced the depth of cut down to a 1/4 of the recommended cut depth for the particular bit being used. On the current job I am cutting into epoxy resin using a idc Woodcraft ‘0’ flute cutter Recommended depth of cut is 0.250″ I have sent mine as shallow as 0.07″ but this did not help
tried several different cutters, woods, feeds and speeds etc.
Shouted and swore at the computer, the longmill, my dog; etc.
I have tried running the job without the cutter in the spindle and everything works just fine. So I’m guessing that the problem only shows itself when the machine is under load – but I’m definitely not and engineer!!!
Greatly appreciate and thoughts, suggestions, help, advise; this is driving me crazy and made me late with Christmas gifts.
I have struggled with disconnects myself on my mk2. It initialy happened in long laser-jobs, but nkt always and slowly progressed into short period certainties in anything.
I could write a bible on what I tried to solve the problem but lets start with my solution.
It turned out to be a bad usb cable (the one supplied with the machine.) I replaced it with one I digged up in my cable box. It was only 30cm long so I had to ballance my pc on the y-axis, but It worked for days without hickups so I ordered me a set of the most deluxe usb cable I could find -gold plated double filtered extra shielded- and have not had one disconnect since. (Year.)
You have an old printer usb cable lying around you can try?
Totally agree with @Spamming_Eddie that it could be a faulty USB cable. Also have you tried grounding your machine? It’s interesting that the machine runs the job when it isn’t actually cutting. Maybe it has to do with the static/EMI buildup. Some tips here: CNC Issues & Fixes 🩹 - LongMill MK2 CNC
Thank you all for the suggestions. I replaced the USB cable (twice) with no effect. The more research I do he more I am convinced that it is a static issue. Yesterday, as soon as I connected the magnet for the auto probe to the router the spindle started ‘jogging’ backwards and forwards - rotating something like 5 - 10 degrees clockwise then counter clockwise repeatedly until i took the magnet off. I turned off the dust collector but this did not help. I have ordered a dust hose grounding kit from amazon and will fit that when it arrives on Saturday. I will also try grounding the machine as well - any suggestions on how to do this? My shop only has one 110v circuit so I can’t separate the spindle onto its own circuit, I tried temporarily connecting the spindle to a 110v circuit in my house via a very long extension cord but this did not help.
