Polycarbonate Recirculation Ender PC mods Stage1 by dhilipp

Last crawled date: 3 years, 3 months ago

Print Polycarbonate or other materials with 300°C on a cheap machine like this Ender3.
Recirculate air from the heatsink, to heat an enclosure and prevent warping.
This stage one is fully working, but it can be seen as a bootstrap: You will get a bad print first without these mods of course, but it will enable you to get a better print next time, and to build Stage2, which will be a fully printed toolhead, posted here soon.
Generally speaking, printing PC is really a pain, but it could be usefull for printing functional prototypes.
You still need some kind of housing, or, at least a hood, to keep things warm. Ambient temperature is more important here than usually. I use to set the outlet of the heatsink to 80 till 100 °C, which is still fine with the bowden tube and it gives a minimum of about 50°C on the edges of the buildplate. It also preheats your material a bit, or cools it when you turn up the fan for PLA printing. Consider this to be a very good effect when retracting PLA!
It's a good idea to start printing smaller parts, heating up the room while getting bigger.
layeradhesion often lacks, when printing to cold or when the object needs too much moves in y-direction. but it's really possible to print objects, let's say half the size of the buildplate, with this bulletproof polymer.
suggested settings:
-minimal infill as supports, alligned (in cura infill "lines" put one angle in "infill line directions")
-min 3 perimeters to keep in some warmth
-always lift head while travelling
-cura->print settings(3bars_menu:expert view)->experimental->"SLICINGTOLLERANCE: EXCLUSIVE" is mandatory for good fittings and threads to print in the right dimensions
hardware requirements:
-a good mainboard with 2nd hotend terminals for the radial fan and
-2nd temp sensor (same as hotend)
-use a fuse! you need to print at 299°C (silicone insulations are not rated to this)
-update or compile the Marlin firmware (i use a bigtree SKR1.3 in case you want to copy)
-heatbreak without teflon inlay
-and of course stay in place (heating failures are likely to occure)
here you find my marlin version with a PID for Chamberhttps://github.com/RaabenF/Marlin
the PID is adjustable in the menu config->temp->advanced->PID C
sadly there are some problems in the latest Cura 4.7 with profiles, you might have to install 4.6.x if you want to use my included settings
download: https://github.com/Ultimaker/Cura/releases/tag/4.6.2
finally, one sure advantage, is a way much faster heating of the bed.
please let me know what you think of it
and
happy printing!