Some bridging experiments with the E3D Volcano nozzle, may be of interest if you are trying to tune things for printing objects with big bridges and don’t want to use support material.
Originally shared by Richard Horne
Let’s try that again.
#3DPrinting tips on bridging material and spanning gaps - 100mm is the maximum extreme printed here as the model is 200% sized.
The model is - Customizable Bridge test
by Neon22 - Customizable Bridge test by Neon22 - Thingiverse
@Richard_Caunt Here are the underside images, and a new print experiment.
The blue model is a bridging test, it was done when material and nozzle calibration had not been completed. Spanning filament in free space at 100mm.
When you do this test, there is no point tuning settings to do this (and only this model). You need sensible settings you can use in ‘normal’ printed objects. So increasing perimeters or using concentric infill, may produce better results (it also may not), but it’s not always going to be what you actually use in a print.
The important bit it to make sure you have a solid surface after the bridging process to build on, that’s usually why you have an unsupported free-space bridge as you have some other feature above it. In this model is only has a few layers, but you can see that it could now support further printing on top.
The buttercream prints are with material and nozzle calibration completed. What’s interesting is that the top image uses a single perimeter outline :- Note that in S3D the outline perimeter is NOT a bridging process, so will go down at the same speed and settings as all your other perimeter settings. That often trips people up.
The first layer infill across this gap will use bridging settings, and attempt to join up with the perimeter lines (if they have printed correctly). This is where the various angles conflict with the way the slicer decides to join the infill bridge to the perimeter sides. When it can span directly across from point-to-point it usually works the best. - So that’s a good thing to remember if you have a bridging point in your model, rotate the print so that the bridge is straight across (Slic3r is smart enough to usually work this out, other slicing programs are often not so smart).
The buttercream print at the bottom of the image uses two perimeter outlines, it’s interesting that this produced a slightly better bridge, this had very little actual material using the ‘bridging settings’.
For the buttercream prints the key settings were - (ignore the blue print).
Layer height is 0.25mm with the Volcano 1.0mm nozzle.
PLA at 205 Degrees C
Cooling fan at 55% on and a Bridging override of 75% fan
Print speed was at 56mm/sec and perimeters 46mm/sec, Bridging settings Bridge settings - increased extrusion rate by 10% and lowered print speed by 50%.
Print time is 21 minutes when scaled to 200%.
