Prusa MK3 low noise fan shroud (40° angle)

prusaprinters

<p><strong>I discovered that the suction of the hotend cooling fan cools down the left side of the heated bed. I measured differences of about 5 °C between the left and right side. Also I don't like that the angled part cooling fan sucks in more warm air from the heated bed.</strong></p> <p>The existing fan shrouds didn't satisfy my needs. For example they restrict the airflow too much, which results in noise. Also weight was a factor as I want the extruder as light as possible (yes it's very minor, but every mg counts in my opinion ;D).</p> <p>I also linked <a href="https://www.thingiverse.com/vekoj/designs">vekoj's revised MK3 Extruder</a>, because in my Fusion 360 source file I used the radial fan model from his step files. Also It's the extruder I'm currently using and it works absolutely great!</p> <p><strong>With Source file</strong><br/> I have added the .f3d source file as I hope more people would add source files to their things. Often I want to modify a thing and having only the .stl file it's more cumbersome than it should be in my opinion. So I don't want anybody to get frustrated when they want to modify my design.</p> <h3>Print instructions</h3><h3>Print Settings</h3> <p><strong>Resolution:</strong> 0,2 mm height and 0,4 mm nozzle<br/> <strong>Infill:</strong> 100%<br/> <strong>Filament:</strong> 3DPSP PETG transparent green</p> <h4>Hotend fan shroud:</h4> <p>This should print easy withoud special settings.</p> <h4>Radial fan shroud:</h4> <p>This is a little bit tricky to print nice with PETG.<br/> I wanted it to be transparent, so lowering the temperature wasn't an option for me. My first print with the generic PETG profile of Slic3r-PE had sagged down overhangs. For the second attempt I upped the part cooling fan speed by ~20% and the result came out great (see the pictures.) But it's really dependend on the used filament, printer and ambient themperature, so finding the right settings is required.</p> <h3>Post-Printing</h3> <h4>Radial fan shroud alignment</h4> <p>Because of the to big screw holes of the fan, this isn't self aligning itself.</p> <p>First loosening both fan screws, then center the shroud on the fan and retighten the screws (this is how I installed mine).</p> <p>I thought about making the screw holes on the shroud a smaler diameter, but then there are still the big screw holes in the fan and so it could still get out of alignment.</p> <h3>How I Designed This</h3> <h4>How I eliminated the uggly seam line in my radial fan shroud ...</h4> <p>My first design had the thin shroud part exactly two perimeter lines wide (when sliced for a 0.4 mm nozzle). So the nozzle moves "left-&gt;right" for one layer (starts and stops on the same side). This resulted in a very ugly seam line where one edge was visibly fatter than the other (twice as thick).</p> <p>I fixed this by making the part wider, so when sliced, there is now infill between the perimeter lines. This results in the movement "left-&gt;right-&gt;left" and the nozzle stops "inside" the layer and not on the outer edge.</p>