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[Solved] Print Warping

Posted: Tue Jan 10, 2017 11:04 pm
by noname117
I have noticed that the larger prints on my Rostock Max v2 have a significant issue warping towards the z tower. The initial layers are flat against the bed but later on it will start to peel up towards the print head. This only happens at the z-tower and no amount of re-calibration has fixed the issue so far. I have only been printing in ABS so i don't know if the same thing happens on PLA or other types of filament. The hot end is set to 230 C and the bed is at 90 C with glue applied as recommended in the users guide.

Edit: Isolating the fan and preventing air from flowing down on to the print seems to have fixed the issue of prints warping up at the z-tower. However, due to uneven heating on the bed, ABS prints still tend to warp to some degree towards the edges on larger prints. Hotter bed temps (100+ C) help reduce the warping.

Re: Print Warping

Posted: Tue Jan 10, 2017 11:49 pm
by nebbian
Is your part fan on? It needs to be off (or at a minimal speed) for ABS. Also check that your hotend fan isn't blowing air downwards. I had that issue on my printer, and ended up making a shroud for the hotend fan so that the intake end wasn't flinging air downwards and spoiling one end of the ABS part.

Re: Print Warping

Posted: Wed Jan 11, 2017 12:06 am
by noname117
nebbian wrote:Is your part fan on? It needs to be off (or at a minimal speed) for ABS. Also check that your hotend fan isn't blowing air downwards. I had that issue on my printer, and ended up making a shroud for the hotend fan so that the intake end wasn't flinging air downwards and spoiling one end of the ABS part.
The layer cooling fan isn't on, however, the heatsink fan on the hot end could be blowing air down on the print. It would make sense since that fan is on the z-side of the hot end. Ill have to check that tomorrow.

Re: Print Warping

Posted: Wed Jan 11, 2017 8:09 am
by geneb
The way the heat break fan is oriented makes it pretty unlikely that it's blowing air on the part.

You can make an ABS print warp off the bed simply by walking by the printer too quickly. :)

g.

Re: Print Warping

Posted: Wed Jan 11, 2017 5:57 pm
by Dale Eason
Hmm, I have been having a problem with ABS prints lifting off always on the down wind side of the HE280 hot end. I thought it was a leveling problem but could never fix it for good. Tried rotating my print surface but it still lifted in the same spot. I have even tried enclosing the printer in thick garbage bag plastic. That stopped tall parts from splitting but I sill got lifting parts.

I wonder what would happen if I unplugged the Fan. Would that cause other hot end problems and not be a good think to try. Suppose I could reorient the hot end and see if the lift area changes places.

Dale

Re: Print Warping

Posted: Wed Jan 11, 2017 7:55 pm
by Ravitch
The easiest way I found to stop my abs prints from warping is to print in PETG, and convince everyone of my Hubs customers to switch to PETG. Same cost zero hassle. :)

Re: Print Warping

Posted: Thu Jan 12, 2017 2:02 am
by nebbian
geneb wrote:The way the heat break fan is oriented makes it pretty unlikely that it's blowing air on the part.
What surprised me was that the air was being flung out from the intake of the fan. There appears to be a bit of turbulence that gets pushed out at about a 45 degree angle, in a cone shape, from the intake end of the fan, possibly from the blades making the intake air spin around. It's not obvious, but it does affect ABS, at least it did for me. I solved it by making a shroud so that air can only pass through the shroud from near the centre of the fan, not from the edges.

It's unintuitive, but putting the shroud around the intake end of the hotend fan solved my warping issue.

Re: Print Warping

Posted: Thu Jan 12, 2017 10:10 am
by AlanZ
To see if it's a fan issue, try rotating the entire effector plate assembly and see if the warping goes to a new area of the print.

Re: Print Warping

Posted: Fri Jan 13, 2017 1:31 am
by noname117
AlanZ wrote:To see if it's a fan issue, try rotating the entire effector plate assembly and see if the warping goes to a new area of the print.
What I did was I cut a thin piece of metal and placed it under the fan against the heat sink. This has significantly reduced the amount of warping in towards the z-tower however because the bed heats unevenly, any far edge of the print has a tendency to warp up when printing in ABS, The colder the bed temp, the more warping occurs.

Re: Print Warping

Posted: Tue Feb 07, 2017 10:14 pm
by cyber.shifter
nebbian wrote:Is your part fan on? It needs to be off (or at a minimal speed) for ABS. Also check that your hotend fan isn't blowing air downwards. I had that issue on my printer, and ended up making a shroud for the hotend fan so that the intake end wasn't flinging air downwards and spoiling one end of the ABS part.
I think I'm having a similar issue to this.. Do you still have the .stl of the shroud you made? Or did you just make something with found bits?

Re: Print Warping

Posted: Tue Feb 07, 2017 10:26 pm
by noname117
cyber.shifter wrote:
nebbian wrote:Is your part fan on? It needs to be off (or at a minimal speed) for ABS. Also check that your hotend fan isn't blowing air downwards. I had that issue on my printer, and ended up making a shroud for the hotend fan so that the intake end wasn't flinging air downwards and spoiling one end of the ABS part.
I think I'm having a similar issue to this.. Do you still have the .stl of the shroud you made? Or did you just make something with found bits?
I just used some random bits to isolate the lower part of the fan from the print head. I also have since switched to the HE280 which hasn't had the problem so far.

Re: Print Warping

Posted: Tue Feb 07, 2017 10:33 pm
by nebbian
cyber.shifter wrote: I think I'm having a similar issue to this.. Do you still have the .stl of the shroud you made? Or did you just make something with found bits?
Sadly I can't find the STL. It was a bit cobbled together tbh. I've since moved on to a totally different effector design.

Here's a picture of what I ended up with, if that helps. I found that it was important to enclose the entire blade path, otherwise air gets flung out tangentially from the spinning blades.

Re: [Solved] Print Warping

Posted: Wed Feb 08, 2017 3:56 pm
by cyber.shifter
Ok, that's good info. I'll see what I can put together. I'm going to upgrade to the HE280 soon, but I have to finish this project I'm working on before I can take the machine down to do the upgrades.