Fixture printing cooling duct

[ehegenberger]

If it's just split for printability, the cooling duct lends itself well to fixture printing. This is a great way to print awkward parts without supports... if you don't have a multi-axis printer handy. :) There are plenty of other applications too, such as saving a failed print, extending an existing print, or mass-producing parts that would otherwise need tons of supports.
First you print the part, minus the offending detail, upside down (I cut the end down at an angle for, uh, printability:

Then you slice and print some fixtures to hold it in place together with the extra bit hanging above it (just use the part as a tool to cut the fixtures, then offset the faces by about 0.1 mm for a tight but not too tight fit:

Slip in the part:

...and continue printing:

All done.



Just to be real sure the nozzle was stuck on well, I had the part sitting upside down on the heated bed while the fixtures were printing, turned off the fan, turned up the extruder temperature and dialed back the speed, which is why it actually looks as though it was heated and mashed in place, and why the top of the (PLA) fixture started to marshmallow a bit.

Full instructions: https://youtu.be/ppp0wPxbjSo

[TheOnlyMann]

This is a really innovative way to essentially print it in 1 go essentially, without having structural integrity failure- however actually having stl files to test upon might be a more useful endeavor, is it not?

[ehegenberger]

You can give these a try, but bear in mind that every printer/slicer combination may vary just ever so slightly:
Cooling duct fixture printing.zip
My settings:
PrusaSlicer, 0.4 mm nozzle, 0.15 mm layers
Prusa MK3S+
Part: generic PETG
Fixtures: generic PLA, bed at 75C
Nozzle: generic PETG, extruder at 250C, fan off for first layers (started this just before pause hence the molten PLA in the picture).
If you try it, let me know how it comes out. This will all become somewhat moot once we can print in 4 axes! :)