May 11, 2019 at 12:58 pm #100106
I completed my mpcnc about a week ago, and i cabribrated the whole thing yesterday. It’s really accurate, but i have one small issue: when cutting from right to left ( cutting towards the top ) the whole Z axis starts to rumble.
My machine’s specs are:
1m wide 1m deep, 10cm legs, 30cm Z axis conduit & leadscrew length, 200w spindle, ramps 1.4 +3 drv8825 drivers ( x & y in series ) and single flute 3,175mm bits. The voltages are adjusted as told in the guides, and i use the ‘official’ mpcnc firmware.
I suspect it has something to do with the larger Z height, but before i start cutting the leadscrew, i would like to know for sure if this is likely to be the issue.
I tried changing speeds ( higher speed = less rumble, i only cut mdf at the moment ), i also tried less & more tension on the belts, but the problem is still there.
Has anyone experience with this issue? I’m fine with cutting the Z length ( i don’t need it that long anyway ) but if it’s not needed, i prefer to keep the rod as is.
Thanks in advance!
Attachments:May 11, 2019 at 1:08 pm #100108
Is it climb cutting in that direction? the router bit might be pulling the machine along in that direction.May 11, 2019 at 1:15 pm #100109
With climb you mean, cutting in the same direction the spindle moves? I think it is indeed. I watched the machine for quite some hours, and it seems it also overshoots in that direction, and then the spindle sounds like it slows down a bit.
So the Z axis height probably has not much to do with this issue, it’s just a weak motor for this job?May 11, 2019 at 1:40 pm #100112
Try a new router bit and shallower passes
1 user thanked author for this post.May 15, 2019 at 11:37 am #100589
Allright, i made some progress:
It’s caused by ‘overshooting’. Climb cutting is off ( im using estlcam ), im using conventional milling for all tests. What did help hower, is adding a finishing pass with 1mm roughing tolerance. The result was a lot better! However, i still have some overshooting ( cutting too far ).
I tried a couple of things:
– x / y acceleration to max 100 ( instead of normal 400 ) > helped a bit
– cleaning all the pipes, loosening all bolt with bearings a bit ( i had them quite tight ) > helped a LOT! The extreme rumbling stopped, but is still overshooting a bit.
– less deep passes ( 0,5mm – 2mm ) >better, but still some overshooting.
What could the final issue be?
Is it okay if i make a video and post it so you guys can try to find the cause of the problem? I honestly tried so much already, but i just can’t seem to figure this one out.May 15, 2019 at 2:17 pm #100608
On a sidenote: i did not buy the kit from v1engineering because of shipping costs ( i was on a tight budget because i had no job ).
I will do a donation however because i’m extremely satisfied with the machine! Just have to wait for my paycheck to arrive ( just got a job ) and then i’ll send a donation, regardless if you guys can help me with the issues or not.
Edit: i think i found the issue…
I have the belts on both sides attached with a gap, instead of just one and the other one tight to the plastic. I’m going to adjust this now, and will post my findings later.
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