This is a redesign of the Space Invaders Carriage for Eustathios printers. The main reason of the redesign was to make it smaller to increase usable build volume. Here's some of the changes:
- smaller size, XY travel is about 290mm² (still less than the original carriage)
- self-aligning bushings instead of graphite bushings (they use up less space)
- 40mm extruder fan instead of a 30mm fan (less noise)
- no longer supports mounting a direct drive bondtech
Like the previous version, it is convertible between a bowden configuration and a direct drive configuration using a Printrbot Gear Head extruder. But, instead of switching, I opted for a flying extruder with a short bowden tube (more about that setup in this post). The hotend is mounted quite a bit higher than with the stock Eustathios build, so the bed probably won't reach the nozzle with the standard configuration (should work with the ballscrew bed mounts).
-- Atomic Glow in the Dark PETG
-- IAP Clear ABS
The extruder uses two 50mm x 15mm blower fans for part cooling. I'm using removable glue dots to keep them in place. I rarely run them at 100%, typical values I use are 60-80% for PLA, 0-20% for ABS.
The cooling duct is held in place with 5x5mm magnets that are press fit into the carriage and duct. If you set polarity of the front two magnet sets opposite of the back two, it will be easier to attach (otherwise the back duct magnets will stick to the front carriage magnets when putting it on)
The top and bottom clamps attach to the end of the screws and hold the hotend in place.
I'm using two 2W 12V LED modules* wired in series (I'm running a 24V system) to light up the extruder. I have them wired on a separate mosfet and configured to indicate when the hotend is hot enough to extrude. One of them went out (intermittent connection) and I'm waiting for a replacement so they don't show up in the picture.
Brass M3 Press Fit Inserts
The holes on top of the extruder and the fan mount are designed to work with brass press fit threaded inserts.
I switched to the more commonly used self aligning bushings as they're much more compact. Overall, I prefer them, they align easily and you can slightly misalign them if they're too loose. The one thing that's really inconvenient though is they're difficult to remove if you want to reuse them.
I wired the heater and thermistor on a separate connector from the fans and lights. This makes it easier to switch out just the heater block.