Help with UM3 ABS prints: rough walls from dual nozzle swaps?

[LloydXmas 0]

I just upgraded to a UM3 and could use some advice on getting better ABS prints. 

As you can see in the photo there are a lot of short strands protruding from the walls. It seems to be a result of where the nozzle is retracting or switching to/from each filament's nozzle. I've tried adjusting the printing temps between 220-240 but that doesn't seem to be fixing it. My other settings are pretty much Cura's default for 0.4mm ABS. Any idea what's causing this or suggestions on how I could fix it? Thanks.

    

 

[Smithy 1,135]

It is a dual color print, so have enabled the prime tower? Cannot see it.

I guess it is the standby nozzle which oozes a little bit.

 

Another idea is to turn off combing, I had similar issues with PETG and a similar object like yours and turning off combing helped. Not completely but it was a way better.

[gr5 2,004]

prime tower is probably the best solution as smithy says.

 

Why ABS?  That's not really the best material for any application I know of.  If you want strength, ABS is no stronger than PLA.  If you want high temperature consider PETG.

[LloydXmas 0]

Thanks for the feedback. I'm not printing with a prime tower and I'll try that.

6 hours ago, gr5 said:

prime tower is probably the best solution as smithy says.

 

Why ABS?  That's not really the best material for any application I know of.  If you want strength, ABS is no stronger than PLA.  If you want high temperature consider PETG.

I may try PETG in the future. I use ABS for its long-term durability outdoors (chemical, heat & impact resistance are pluses). I don't see native support for PETG in Cura or Ultimaker, which leads me the think I'll have to sift through several forums and blog posts to troubleshoot problems.

[Smithy 1,135]

In Cura you can use the generic CPE material which is a kind of PETG. For PETG it is important to print slow and often it helps when you turn off the combing feature in Cura.

 

ABS is not the best choice for outdoor because it is not resistant to UV light. ASA which is a kind of ABS is better for outdoor usage.

 

PETG has similar properties as ABS also heat resistance if you choose CPE+ or ColorFabb HT material.

 

It is not wrong to use ABS but due the toxic fumes and problems with layer bonding and adhesion it is nowadays not the first choice for such requirements.

[LloydXmas 0]

I paint my ABS parts to protect them from UV damage, however it would be nice to try printing with something more forgiving.

Is CPE+ more/less challenging to print with? From the what I've read on ASA, it seems more difficult than ABS. 

 

Printing the prime tower eliminated 90% of my ABS issue btw, thanks. 

[Smithy 1,135]

I had no issues with ASA, but I printed just a few parts.

 

It depends on the part (shape) of your model, but for me, CPE+ works better and easier than CPE. With CPE or normal PETG, I got a lot of zits and stringing. You can only try it. 

 

Regarding Print Tower, you can also try to manually put the tower near to your object. The default location in the back right is often not the best choice.