January 25, 2017 at 4:11 am #25942
I have assembled my MPCNC very secure. Everything has the right dimensions, is rectangular and running smooth without backlash. Only one problem, the Z-axis in one direction is not 100% perpendicular with the table, its hanging a bit (about 2 mm) skew in the middle assembly, see the pictures.
Played with the tension of the bolts, but that doesn’t help. Anyone an idea/suggestion what I can do more?
Attachments:January 25, 2017 at 4:34 am #25946
How big is your cnc and are your outside rails perpendicular with the table?January 25, 2017 at 4:56 am #25949
It’s 800 x 600 mm, rather big but it is standing like a rock with 25 mm stainless steel conduites with a wall thickness of 2mm.
Yes it is perpendicular. Checked everything at least five times, heights, lengths, diagonals, perpendicularity, rectangularity…January 25, 2017 at 9:03 am #25957
That is a new one.
Can you put up a few pictures at different angles of you middle assembly. I have a feeling something is missing.January 25, 2017 at 9:09 am #25958
Is that tool mount sitting perfectly flat on the z rails… Looks like its twisted like the holes were drilled not totally vertical.
Or a piece that warped slightly when printing?January 25, 2017 at 9:10 am #25959
I’m thinking the spacer is missing or the z rails are not parallel.January 25, 2017 at 10:22 am #25965
Thanks for all your replies.
I am afraid my camera on this short distance has a little distortion. There’s nothing twisted nor is there any friction.
The spacer is on it’s place too. I spent hours checking everything and I don’t get it. Tomorrow I am going to disassemble the middle part so I can check on bad prints. The prints are in PLA so the chance of warping is small, but you never know…
The Z-axis is perfectly straight and with parallel rails.
Attachments:January 26, 2017 at 1:58 am #26011
I think I know what’s wrong. Took the middle assembly apart and it appears that the XY-parts are not printed right-angled from the printbed. There’s a mm play on the height of 10 cm of the part so I think it turns out to 2 mm play in the Z-rails.
At least, I hope this is the cause. I printed this XY parts at the end of all needed prints and did some printer maintenance before because of the 12 hours printing session. It seems I did something wrong with the printbed guidance that causes this little deviation.
Printing once again now…
Thanks for your thoughts.
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