First print on Ultimaker 2, almost perfect, how to improve?

[aroth 1]

I just unboxed my Ultimaker 2 and run through a test print of the included robot example. I think the results came out quite well, particularly compared to some of the other 'first print' examples I saw when I was researching my purchase.

However, I'm seeing some minor issues that seem to affect only the right half of the model. Here's a picture:

Can anyone give me any pointers as to what might be the cause of these issues, and how I can fix them?

I'm guessing maybe the right side of the build platform is slightly outside of level? Should I go through the leveling process again?

 

[IRobertI 520]

No, this is not a bed levelling issue, it's a cooling issue. The bed level is irrelevant once you get past the 2nd to 3rd layer. The reason the right side is worse is because the right fan doesn't quite reach this tiny print to cool it properly before the next layer is put down. By printing two copies at once you give the print more time to cool.

Some more info regarding overhangs can be found here:

http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#overhangs

 

[aroth 1]

Thanks, does that mean that increasing the 'minimum layer time' in Cura should also result in a better print?

 

[eldrick 65]

Try printing one of the fan ducts by Venkel: https://www.youmagine.com/users/venkel

These improve cooling to the point where you will often turn the fan speed down, and also kill a lot of fan noise from the metal shroud.

 

[IRobertI 520]

Well my reply up there looks a bit stupid now since the person I was correcting decided to delete his post...

As for your follow-up question regarding minimum layer time. I'd say no in this case. What that setting does is to tell cura to slow down the print speed so that every layer takes a minimum of X seconds to complete. If you set this higher the nozzle might be spending way too much time on top of the print and will transfer a ton of heat into it.

 

[aroth 1]

Try printing one of the fan ducts by Venkel: https://www.youmagine.com/users/venkel

 

Thanks for the suggestion. I printed one of those (specifically, the 'V06' one found here:

https://www.youmagine.com/designs/ultimaker-2-fan-mount-dual--2

...and it made a fairly noticeable difference:

It's enough of a difference that I'd suggest changing the geometry of the shroud that ships with the UM2 to provide more symmetrical cooling for the single installed extruder. Although I guess since the printer can print its own mods, its kind of a moot point.

 

[Blizz 53]

I've been considering printing one for a long time but I was wondering if printing them in PLA isn't a risk? Its pretty sensitive to heat and so close to the printhead... Might be better in ABS no?

 

[aroth 1]

Yes, I was a bit concerned about that myself, given that I'd have a plastic shroud in close proximity to the thing that gets hot enough to melt the plastic used to make the shroud.

In practice, however, it seems to work fine. Even with PLA. It constantly has cool air circulating through it, which probably helps. And it seems like the worst-case failure scenario is that it melts/deforms enough during the print that it comes into contact with the printed object and causes the print to fail. I can live with that.

It probably wouldn't be a good idea to use a shroud printed in PLA to do printing with ABS though.

 

[Blizz 53]

You make valid points. I guess I'll just print it in PLA.

On the other hand, I'll probably include a spool of ABS on my next filament order and print it again.

Thanks for trying this and reporting back, I had no clue which of those would work or not

 

[aroth 1]

No worries. And when you go to print it, I found that I got the best results orienting the part vertically (i.e. in the same orientation that it gets installed in) and then telling Cura to cut off the bottom 1.45mm of the part.

It printed without doing that last bit, but a good portion of the bottom ended up being printed over the air and came out with a very rough surface (strands of filament going off in all directions) as a result. By cutting off the last 1.45mm I was able to get a perfectly flat bottom layer, with no negative impact on the shroud's performance as far as I can tell.