Printrbot print a oval instead of a circle

[elso154]

Hello, i had bought my Printrbot at Kickstarter must i Update the Firmwear if yes which (Link please)
Is that Problem known so tell me how you have solved it!?
Bests from Germany

[RetireeJay]

Possibly your X and Y calibrations are not balanced. You should make adjustments to the calibration constants by using G-Code commands.

Don't try to re-flash the firmware; it's very complicated and completely not needed.

There are many threads in these forums on calibration.

However, there are other possibilities. For example, check to be sure your pulleys are securely attached to the center of the flat part of the "D" shaped motor shafts; check your belt tensions, etc.

[rsilvers]

Look in your start-up G code for something like this:

M92 X129.919 ; calibrate X
M92 Y190.735 ; calibrate Y
M92 Z2267.720 ; calibrate Z

Print a cube - like 20x20mm or 1x1 inch. Measure the result with calipers, and then correct how many steps are needed per mm in the M92 commands.

[Tdeagan]

I had a similar problem that related to the mount for the X-axis motor. See

[ohbaby714]

[RetireeJay]

These numbers are steps per millimeter. So if your X number is 130, that means the software will issue 130 steps to move 1 millimeter, or 1300 steps to move 10mm. If you print a 10mm cube and find out that it's 10.5mm large in the X direction, that means you moved too far; you had too many steps. So 1300 steps was too many.

Correct it by taking the fraction of the desired distance over the measured distance, and multiplying by the steps per mm.

I think of it the easy way: I know I need a fraction, and I know the number needs to be smaller, so I put the smaller number on top: (10.0 / 10.5) this gives me 0.9524. So now I multiply 130 X 0.9524 and I get 123.81. That will be my new steps per mm.

There is a web-based calculator that will give you correct starting numbers for your calibration, based on the belts you are using, etc. See this post for a link and Printrbot-specific settings. viewtopic.php?f=16&t=3924&hilit=+prusa