I am trying to print Emmett’s Secret Heart Box http://www.thingiverse.com/thing:44579 in PLA and the top is not bridging properly. The rest of the print looks great! It was printed at the lulzbot supplied medium pla settings but with a 20% infill, 3 perimeters, 4 top, 3 bottom. Speeds, cooling, etc were not touched from that ini.
Here is a picture and you can how none of the top parts made it all the way to the side. the bottom section of the top did better with its shorter distances but the first layer of the top also did not full bridge there also but but the time the 4 layers were done it was at least closed.
Any ideas?
Do you have a fan on the extruded filliament? I believe PLA pretty much requires a fan for proper bridging to work.
I have the fan running on the Taz4 using a shroud that blows both on the path as well as the fins of the hot end. The Bridges fan speed is set to 100% in Slic3r and other wise after the second layer its between 35%-90%.
Other settings related to bridging are:
The print speed for bridges is set to 25 mm/s which was in the ini file.
Detect bridging perimeters is selected.
Acceleration Control Bridge: 1000 mm/s2
Don’t support bridges selected (but support is turned off anyways)
Bridge flow rate 1.15 …maybe should be a little higher? The threads of filament were not touching.
I tried going slightly higher on the bridge flow rate and also cut the bridge acceleration down to 600 but both changes did not really help much… Also I see this on three different types and brands of PLA.