Bulging on corners(ABS)

I have a RepRapPro huxley (xmas 2012) that has a problem printing sharp corners in ABS. The print quality is normally quite good, but sharp corners often bulge upwards. The esteps is not too high -- the infill actually has gaps, so if anything, it is too low. I am using solidiidle abs at 225 *C, although the same problem occurs at ~205, the lowest temp I can reliably extrude at. Bed temp is holding at 120 *C, and is ~100 *C at the surface. Currently, I am suspecting the bed springs, they are barely strong enough to hold the bed up under it's own weight. I am using Slic3r 0.99, and my settings are attached. Any suggestions?

Pictures:
http://www.flickr.com/photos/95652985@N07/sets/72157633472960920/

P.S. I forgot to mention that there are no bed adhesion issues - the bottom of the print is stuck thuroughly to the kapton.

Thanks for the help!

Edited 1 time(s). Last edit at 05/11/2013 05:46PM by ConnorGames.

the glue on the kapton becomes weaker (temperature), i saw on my printer that the object is bonded to the kapton but the kapton not to the bed. do you have more pictures of the corner with the bed visible?

Doesn't look like that is the issue Gerard, I don't know if you have even checked the pictures?

You might try a getting a fan to blow on the print, that helps in some cases. Have you tried lowering the bed temp?

Are the corners separating from the bed (warping)? Its hard for me to tell in that picture...

Edited 1 time(s). Last edit at 05/11/2013 07:29PM by Crussell.

The corners were not lifting from the bed nor the kapton from the bed. I might try working on the bed springs, does anyone think that would help? I don't want to relevel my bed unnesisarily.

I have tried a fan on the print, but this cools the bed and causes the print to detach.

Now that I think about it, i believe lower extruder temps did help some. I think what is happening is that the layer below doesnt set combletely, so the next one pulls up on the corners when it contracts. I'm going to try 210 *C. Wish me luck!

Edited 1 time(s). Last edit at 05/11/2013 09:45PM by ConnorGames.

I dont know of anything else that would cause that but If those springs are as weak as you say they are then it sounds like they need to be changed anyway. Start there and keep us updated on what happens!

you are using slicer 0.9.9 you can try changing this in ini file
gcode_arcs = 0

to this

gcode_arcs = 1

but it is experimental. what is happening is there are several moves calculated for angle arcs in corners, and the slow down likely causes filament to build up.

you can also change the resolution in the print settings advanced tab in slic3r, look for resolution and change it to 1mm.

both methods work differently but they achieve the same thing, arcs are traveled thru at full speed, leaving little extra filament around the corners.


edit: i did not see gcode_arcs in my 0.9.9 slic3r ini file.

Edited 3 time(s). Last edit at 05/12/2013 06:01AM by jamesdanielv.

I don't think it's your bed leveling issue.
Have you tried slowing down the print when it prints those thin wall? I did that and also had to use fan occasionally.

To much filament causes that problem with me. Usually when i have my calibrations off a little, either extruder or XY. Also if the corners curl up a hair bit on the first layer it can do that.

Just upgraded the springs, nothing else changed. Print is only on layer 28, but the corners are not bulging. Last time, this was noticeable before layer 10. I now remember rapid acceleration/deceleration used to cause the bed to tilt, this probably lifted the corners. Either way, it seems the problem is MUCH less significant or even SOLVED with the new springs! The overall print quality seems to have improved, and I believe the infill/perimeter overlap problem I was having also got solved.

Pics coming soon!

Glad you got it all worked out!