Printing less than 5mm lines = ugly corners and bridges

Hi all,

I'm having this issue with my Prusa i3 for a while now:

(Check the attached pictures)
Pic1 -> A 20mm cube comes out fine (imho).
Pic 2 -> A 5 mm cube is a mess!
Pic 3 -> A 50mm bridge comes out perfect (imho).
Pic 4 -> A 5 mm bridge is a mess!

When I print small lines, area's or bridges, the print quality is really bad. Corners are very rounded, bridges are bad. This doesn't happen when I print larger lines/area's.

What could cause this? Could it have something to do with belt tension or do I need to make changes in my firmware?

Thanks in advance for your experienced suggestions!

--Kenny

Edited 2 time(s). Last edit at 04/24/2014 05:50AM by Cagy.

It is strange, how can a bridge 50mm to be so nice without support??

Good settings, a fan on the extruded plastic, other factors. I managed to get good bridging by turning a fan on the plastic as it comes out, and slowing down the print speed during bridging. It works.

---

MakerFarm 8" Prusa i3v
RAMPS 1.4
0.4mm E3D v6 for 1.75mm

Quote
alfadex
It is strange, how can a bridge 50mm to be so nice without support??

I printed this bridge without a fan. Only by decreasing the bridge speed to 30mm per second.


Updates & Solutions on the actual problem described above:

This is a 'general' problem with these type of printers, the layers just don't have enough time to properly cool off.
Possible solutions:

• Use a fan
• Set a minimum layer time for each layer
• print multiple objects side by side (so the layer has time to cool off more)
• etc