Flat-sided cylinders

[Yepher]

I think I will have this problem solved but I am posting it here in
case someone else has this problem or can provide other ideas on how
to solve it.

While assembling my 3D printer (ToM) there was a tuning step that I
skipped over. You are supposed to print out some solid cylinders and
make sure they are round. If you have any flat sides this indicates
the flat side axis belt is loose or that you have backlash.

My understanding of the solution (although I can't try it until
tonight) is I need to tighten my timming belt so there is less slack.
I looked through skienforge and found some backlash compensation
values. If you are not using belts (or can't tighten them) than
tweaking this value can probably solver your problem.

-- Yepher

[Yepher]

I tightened my Z Axis and no more flat circles. This also got rid of
some gaps I was seeing in the top layer of my prints :)

-- Yepher

[Douglas Cogan]

Yepher,

Do you really mean the Z axis? Isn't that run on the screw directly connected to the motor? I think perhaps it is X or Y. But let me know if I am mistaken.

-Doug

-- Yepher

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[Yepher]

Good catch Doug. That was a typo on my part. It was the X axis that
was loose on my machine.

[Douglas Cogan]

Thanks. I have the flat sides, too and was wondering which side you adjusted (although I guess it could have been either X or Y.) I think mine is X as well. Did you have trouble accessing the bolts to tighten the X? I had a bear of a time tightening my Y since one of the bolts is underneath the rod and in the corner. I was able to loosen all the bolts but that one easily. I finally got it with hemostats and once that was loose and the belt stretched, I just tightened the 3 easy bolts. So my Y belt seems pretty tight so I think I need to tighten my X which looks just as hard to access.

I actually didn't do any other adjustments in skeinforge yet and other than a bit of flattening, my results seem spot on. I thought I had a problem at first because my calibration cube came out 22.5 mm when measured with calipers (instead of the expected 20) but it turns out that the model really is 22.5 mm when viewing in blender. This is the cube pointed to by the doc, so if anyone else prints that calibration cube, double check in blender before you measure with the calipers. That would have saved me days of headaches.

To answer some other questions that are hanging out there: you asked if I used supports for the 3D knot I made and the answer is no, I just built-it straight up. However, it made the raft and then made the rather thick base for the knot on top of that.

It looks like I will not make it to the build-out this Saturday since it is long sold-out, but there is a promise of a future one (if this is successful which it looks like it will be.) I will bring my bot to a Tuesday open house as Sasha encouraged.

[Yepher]

Yes, the X axis was difficult. I could only tighten 3 screws instead
of all four. My motor is as far off as it can go so I really need to
take the X axis apart and tighten the belt but I have not had time to
do.

BTW, I found printing the Casino chips is a nice way to test the belt
tightness. The are pretty short so they print pretty quick. Before I
take them off the build platform I use my sharpie to label X and Y so
I can identify which belt is problematic.

Luckily my Y belt was already pretty tight so I have not had to deal
with that yet.

Let me know which PS:one you are going to and I will try and come to
that one too.