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.
Yes I did - but I’m not 100% sure how!!! I tried so many things that I can’t be 100% which one (or ones) did the trick. My best guess (based on the order I di dthings in) is either static - I installed a static discharge wire attached to the dust show and wrapped around the outside and inside of the dust hoes all the way to the ground on a wall outlet. At he same time (while I had everything apart) I pushed the control chip on the circuit board to make sure it was seated correctly - It didn’t seem loose to me - but you never know.)
After I did this things are now working properly.
Hi
I am a new long mill mk1 owner. It seems like every time I get close to having it dialed in some other issue pops up. I recently built a nice and sturdy table for it. While trying to surface it my cnc would just randomly stop sending me the “hard limit has been triggered” error even though it was no where near a limit switch. I was beginning to pull my hair out but after thinking about it I started wondering if the static electricity build up on the shop vac hose was causing the z axis limit to trip. I haven’t tested my theory yet but I’ll keep you posted.
Looking to reduce inerference is always a good thing and certainly is something to look into. You might also want to look at your USb cable connecting your pc (or whatever) to the longboard. Assuming you have a longboard.
The USB cable is often overlooked but is as important for the stability of your machine as yhe table it rests on. You want it nice and stirdy.
Shielded, filtered, gold plated are a few terms that come to mind.
Thank you for responding. I will definitely upgrade my usb cable. I’m wondering if there’s any evidence of static discharge affecting the limit switches? It’s the only thing I can think of that would trigger them when the spindle is no where near them, specifically the z axis?
I have the MK1 with the Longboard Rev 1.4.3. If I understand correctly I do not need ceramic caps, is this correct? I have bought a new USB cord and will ground my dust collection hose. Hopefully that will fix the issue.
