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Big Ring Test!

Posted: Fri Aug 31, 2012 4:14 am
by jspark
I just tried to make a big ring for joint testing.
The ring's outer diameter was 160mm.
And It is devided by 4 parts.
I adjust the dimensions of the joint part for perfect connection.
The wall thickness is 3.4mm.
The projection part is 1mm.
The groove part is 1.4mm.
And the results value of outer diameter was 161mm.
I think my UP needs re-calibration.
I'd like to try more bigger one! ;)
Big Ring Joint Testing
jspark_big_ring_test_20120831.jpg (172.98 KiB) Viewed 7931 times

Re: Big Ring Test!

Posted: Fri Aug 31, 2012 8:46 pm
by JuliaDee
0.7% error with four joints, pretty good!

Re: Big Ring Test!

Posted: Sun Sep 02, 2012 12:15 am
by goopyplastic
I haven't explored it fully, but I'm not quite sure how you would calibrate the width of printed objects.

From what I can tell the X1/X2 entries on the calibrate are just proportions and decide the angle of skew in the print, same for the Z offset. If you enter 125/125 or 124/124 you still end up with zero degree X/Y skew in the calibrate options. The Z offset sets the X/Z skew.

The UP! is a fixed design, they know the stepper degree's per step, what microstepping they are using and the drive gear diameter they are using so the x/y/z scaling shouldn't ever change. That being said it seems like the up prints stuff about .7% (calibration prints at 124.8x124.8) larger than normal so scaling the STL's before printing might be the only real solution. I believe the skewing / calibration is to compensate for the alignment issues with the different axis during assembly, there will be some error just from screwing the frame together from the play in the bolts etc.

I'm not sure what the Z height would change as my calibration printed have always been 40mm.

Re: Big Ring Test!

Posted: Mon Sep 03, 2012 9:09 am
by jspark
Isn't it possible to change the size scale through the calibration work?
As I know, It is possible to change both of size and skew with calibration work.
I have changed the z-direction height 10 ~ 50 mm in order to find the exact value of 40mm.