ABS Coarse Print

Hi, I recently got a LulzBot Taz 6 printer and we tried to print something but it failed in a way I have not seen before. The print is very coarse where all the layers sort of expanded outward. And the nozzle got stuck in the print, causing the cura software to terminate and resulting in a runtime error. We did have a successful print before this, so the sudden failure is strange. I’ve attached pictures to help. One of the pictures shows the settings we used for Cura. Any help would be appreciated.

Was the successful prior print also in silver/gray abs? That tends to be another one of those difficult to print colors. Try adjusting the temperature up 5 degrees. Also if this is different fillament, you may want to see if you are overextruding. A thin layer like that can also benifit sometimes from a fan, which usually isn’t a good idea with ABS, but in this case it could either help or cause additional splitting.

Making the walls thicker if at all possible will improve the resulting print significantly.

Was the other print also that bowl? It’s almost all overhang, at that temperature it isn’t going to work well which will result in a rough outer surface. I can print steep overhangs succesfully with ABS and no supports by using a slow outer perimeter, fan at around 30 or 40% and temp at 230/225. But taking into account piercets post above that’s probably not possible with silver, I’ve only ever used white and black.

Also as piercet suggests use more perimiters and make sure they’re a multiple of your nozzle size. You need at least two full perimiters to succesfully print overhangs from my experience, the more the better.

Oh, yeah 260 is wayyyy to hot.

Another thing to take into account is making sure your filament diameter and/or flow rate are bang on for prints like that. Over extrusion is anathema to overhangs.

Before we got the Taz 6 we were using an Ultimaker and that one really only does well when the temperature is set that high for ABS, at least in our experience. So you advice is to increase the shell thickness? What is it you mean by perimeters? The other part was not the bowl, so that may explain the trouble. I’m going to try lowering the temperature a bit too.

Also, what is it about the silver/gray filament that makes it harder to print with than the black or white?

White is about as hard to print as Gray/silver. My theory is that both of them use metalic oxides for coloring, in those cases titanium oxide, which may radiate heat slightly better, but I don’t have a better answer for you beyond that.

Perimiters are perimiters. So assuming you’re using a .5mm nozzle a 1.5mm shell thickness would have 3 perimiter lines. Shell thickness really should be a multiple of nozzle size.

I’ve no idea about silver filaments having never used them but try some small experiment prints with similar angles with different settings. Start with a low temperature and increase a small amount each time until you get it right. Try an outer perimiter (or shell if that’s what cura calls it) speed of 20mm/s and increase it in small amounts until you start to see a dip in quality. Likewise fan speed, start with maybe 40% and drop it lower until you see a dip in quality.

Refine your settings on smaller prints that can be done in a few minutes then you don’t waste a lot of time and plastic if/when a big part fails. Make sure in your tests you use the same layer height, shell thickness etc as these things directly impact ability to print overhangs.

Temperature and fan speed can be controlled via the LCD mid print so you can change things about as they’re running, you can usually tell off a few layers if your current configuration is working or not, so you can save time by testing different values on the same print, and the impact changing them makes.

Generally speaking you want your temperature as high as you can get it (within reason, up to 240 or 245ish max) and your fan speed as low as you can get it without impacting on surface quality. You could possibly get away with just using the fan on the lower few layers where the overhang is really steep, fan isn’t good for ABS but sometimes a model dictates the need for it.

Thank you for the advice. I will do that and hopefully I’ll end up finding the best settings.