Calibration question

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Hugues
Posts: 273
Joined: Thu Apr 04, 2013 5:36 pm

Calibration question

Post by Hugues »

Hi guys,

I have a Felix 2.0 with Repetier Host, been printing happily for many years.

But I might have a calibration issue, let me explain:
- My CAD file is simply a 30mm D cylinder
- The height of the printed cylinder corresponds to my CAD file
- The Y dimension of the printed cylinder is pretty much 30.00 mm
- But the X dimension is 30.34 mm

So I should calibrate the printer by playing with the firmware settings. But:
- the maximum diameter of my cylinder is not on the X axis, it's roughly at 45 degrees from the X axis (or Y) and is 30.60mm
- the minimum diameter of my cylinder is not on the X axis, it's roughly at 45 degrees from the X axis (or Y) on the opposite side and is 29.67 mm

So basically my cylinder is more like an oval with the longest dimension between X and Y axis.

I'm not sure how to fix this problem. Looks like I need to change the X and Y step but if I do then my Y dimension which is correct will not longer be after ?
Hugues
Regards from Switzerland

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gfeliksdal
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Joined: Sat Feb 25, 2012 10:40 pm
Location: Netherlands
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Post by gfeliksdal »

Hi Hugues,

Good to hear you are still using the FELIX 2.0.
The wrong dimension could also be caused by the following issues.

- Belt tension not correct
- Set screw of x-axis pulley loose
- Belt damaged
- High friction on the axis

Hopefully that helps.

Hugues
Posts: 273
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

Hello !

thanks for your reply. I checked the points below:

- Belt tension not correct:
The Y belt was a little soft so I gave a bit more tension

- Set screw of x-axis pulley loose:
It is ok. To be sure, I also held the step motor axis with some pliers and tried to move the print head assembly but it does not move.

- Belt damaged
I cannot see any teeth missing or worn down.

- High friction on the axis:
None that I can feel.

I also checked the calibration by moving the printer in increment of 10 using the buttons in Repetier host, my results:
X130.51 mm vs 130
Y 109.4 vs 110
Z 39.75 vs 40
So not bad.

Despite all this, I printed a second part (cylinder of D 30) and it's still not round, D min = 30.56 and D max = 31.97
I need to print some wheels for a client, so not that good.

I checked in my slicer for any additional Gcode that could be added and did not find any that could change these dimensions, or scaling.

Anything else that I can check ?
Hugues
Regards from Switzerland

Hugues
Posts: 273
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

Back on this issue.

I checked all the belts and set screws, could not find anything loose really.

So I printed a L shape part to check calibration in X and Y, it was about 4% longer in Y, so I changed the steps per mm in Y then printed again.

Now the X and Y arm of the L shape are pretty much the same as you can see on first 2 pictures:
101.40 mm in X
101.15 mm in Y

So i thought I'm good to go and printed a small disc for a client, the largest D should be 15mm.
As you can see on next 2 pictures, I have more than 1mm difference between largest D and smallest D !
How could this possibly be if my L shape is ok ?
That small disc is visibly oval.

I visualized my gcode online and it shows a perfect circle, not oval.

Point to note, the 2 axis of the oval are not aligned with the X or Y axis, they are about at 45degrees.
calibration X.jpg
calibration Y.jpg
largest D.jpg
smallest D.jpg
Hugues
Regards from Switzerland

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