Bad prints, pls help !!!
July 21, 2015 12:11PM
Hi all, im hawing some problems with bad prints on my Prusa i3. I calibrated axes and extruder and i don't know where the problem is (im new to all of this). This is my first and second print, yellow is PLA and green is ABS. What could i do to get better prints ?

Edited 1 time(s). Last edit at 07/21/2015 12:12PM by Koby_88.
open | download - DSCF6606.JPG (211.2 KB)
open | download - DSCF6607.JPG (221.4 KB)
Re: Bad prints, pls help !!!
July 21, 2015 09:09PM
Looks like z wobble to me, your lead screws probably isn't straight. Try to make sure your z axis doesn't have play in x carriage part
Re: Bad prints, pls help !!!
July 22, 2015 01:15AM
You are right, i just saw that my lead screws isn't straight. I'm gonna try to fix this. Do you think that corners came up like this because of z axis wobbling too ?
Re: Bad prints, pls help !!!
July 22, 2015 09:08AM
The corners problem could be that the temperature of the hotend is set too high. You could also try adjusting jerkxy, if the printspeed is much higher than jerkxy it can cause overextrusion in the corners. The reverse is also true, if jetkxy is set too high it could under extrude in the corners.

Another cause for uneven layers is overextrusion. If you have an lc display, you can adjust the flow while printing, by a percentage. go to the tune menu, which is only available during printing. Adjust by 5% increments or decrements every 5 layers until it prints well, then reset the printer by power cycling or emergency shutdown to reset the flow back to 100%, then adjust the slicer extrusion multiplier by that percentage. this is much quicker than reprinting every time you make an adjustment.

Edited 1 time(s). Last edit at 07/22/2015 09:18AM by imqqmi.
Re: Bad prints, pls help !!!
July 23, 2015 02:00AM
My extrusion was bad calibrated, now results are better but not perfect, can i adjust that 5% increments in the pronterface somehow (without lcd) ?
Re: Bad prints, pls help !!!
July 23, 2015 02:25AM
You can try entering gcode on the manual tab in repetier
M221 S95
Where Sxxx represents the extrusion multiplier in percentage.

I haven't tried it myself but it should work. There will be a delay before the gcode gets executed though.
Re: Bad prints, pls help !!!
July 24, 2015 01:16AM
So if i type M221 S95 it will extrude at 95% of my current extrusion settings, am i right ?
Re: Bad prints, pls help !!!
July 24, 2015 12:47PM
Yep, that's it!
Re: Bad prints, pls help !!!
August 13, 2015 10:49AM
Thanks all for help, i do all like you told me to and my prints are now a much better smiling smiley Last night i had some problem, my printer have moved layer and continue printing on that layer, i don't know how to explain so look at the pictures smiling smiley
What could cause that ?
open | download - 20150813_163508.jpg (473.3 KB)
open | download - 20150813_163513.jpg (530 KB)
Re: Bad prints, pls help !!!
August 14, 2015 03:09PM
As an absolute beginners guess, I would think that something moved during the print - like the belt gear on the Y axis motor had slipped ? Check the grub-screws on the belt pully.

Also using an i3 and on my design there was no support at the top of the Z axis - in my case a vertical standing aluminium plate. I printed small brackets to keep the printer in the same place in my print box, and added a bracket between the top of the Z axis and the printer box, so the top of the Z axis could not move or vibrate.

Print quality improved immediately.
Re: Bad prints, pls help !!!
August 14, 2015 09:23PM
Your Yoda layer shift could be because of slightly low current in the corresponding motor. The direction of the shift tells you which axis it is. If the belt and pulley of that axis are properly tight (see suggestions by others above), then try adjusting the turnpot of the corresponding stepper driver. Just a single layer shift late in the print (as in your Yoda) could mean that you need to turn it up by a little bit, say a bit less than 1/8th of a turn.

(If your cooling on the board and stepper drivers is insufficient it could also be that the motor current is little bit too high, so the driver got overheated and missed a step.)
Sorry, only registered users may post in this forum.

Click here to login