So I’ve been having issues with our @LulzBot printers at work. When we get parts with large cross sections we start getting some fairly serious delamination. This is something I’ve dealt with in printers before but the normal tricks I’ve used aren’t working here.
Details
LulzBot TAZ 4 with LulzBot 3mm ABS
Fully enclosed printer custom extrusion/plexiglass box
Temps: 230 at head and 85, 100, 110,120 at bed. All different attempts.
This particular part is about 6" tall with a 1/4" thickness. Its a formed bracket. I can’t show the full part.
Printed at 20% rectilinear and .22 layer. Used the medium automatic abs support profile from lulz.
Measured filament at 2.84 and changed it in profile.
3 perimeters
Glue stick on PET tape. No warp at bed.
I’ve had this issues with 3 different rolls now. I haven’t tried other suppliers of 3mm because buying it is such a pain at work.
Ideas?
What’s the temperature of the chamber?
I think hex infill might help prevent warping/delamination since it doesn’t have strands running all the way across the part (like rectilinear does) that contract when they cool?
Cooling the part more slowly after the print is done may also help if the delamination is happening while it cools.
pla does better with stuff like this
I have eliminated most of my ABS delamination issues by printing it at 240°C inside a heated chamber at 40°C.
@Jonathan_Haberman I understand PLA would do better. But Ive done this part in ABS on another printer with no delam. The same for other parts. So I am trying to find an answer.
@en_tiresia I can go up to 235 with this hotend. I can try it though.
I usually just increase my infill to make the problem go away.
I print hot as well @Joe_Spanier 255 on the hot end. You could add more perimeters, or the hex infill would likely help too
cant print hotter then 235 on the budaschnozzle. There’s a big difference between a nozzle like that and the e3d too.
We are printing again with less infill now. I thought increasing the infill would increase the shrinking stresses causing this.
@Joe_Spanier Just so that we are on the same page, is less infill = more hollow? If you are having better success with ‘more hollow’, that would be interesting.
Check your fans! If you say that you’re printing the same part at same ambient and nozzle temperatures on another machine with no issues then it could well be airflow.
Even an extremely light airflow from a fan off to the side that is intended to cool the electronics or similar can cause enough cooling to warp/delam prints.
Either that or your hotend temps aren’t quite the same, and you aren’t printing as hot as you think you are. Remember that most thermistors and balancing resistors on electronics have tolerances around 5% +/- and so you could be 10C off from where you think you are.
Dropped to 10% in at rect and it printed with no issue. The fans might be an issue. There’s a large fan on the electronic box for the TAZ that is vented away from the bed but with the walls the drafts could come back.
As for infill here is the basis for my thinking. @Sanjay_Mortimer1 @Thomas_Sanladerer @Pieter_Swart @Andrew_Radovich_BadW you guys can tell me if I’m way off base.
The percentage of infill controls the amount of internal stress on the part. More infill=more shrinking abs=more strength to pull the walls apart. Lowering the infill means only the walls have the shrinking stress and with proper layer fusion and correct # of shells the stresses cannot over come the strength of the bond.
I think this test kinda proved my theory but I changed multiple variables at once so I can’t be sure. In this test I lowered from 20% to 10 and raised the bed temp from 85 to 115 to help the enclosure. Remember that bed adhesion is not an issue in this case.
