BigBrain3D – Retractable Purge Mechanism – Community update #2

Hi All!

We hope everyone is weathering this storm well.

If you are looking for a way to help fight COVID-19 there is an open source ventilator project here and a really neat Doctor created project for splitting the output/input of a single ventilator so it supports up to 4 people simultaneously with a simple 3D printed Y circuit splitter here. That second one is what we’ve been printing with any idle printer time. A 4 person setup requires 9hrs on a Prusa i3 MK3S:

ventilator circuit splitters printed on prusa mk3s
ventilator circuit splitters printed on prusa mk3s

Prints from the community

5 American flag coasters by Lindolfo Arroyo (Mosaic Palette, Palette+, Palette 2 (Pro) Users Facebook group)
Retractable purge mechanism print. Author unknown
MultiColor RPM print by Klaus Knute

Now for some ‘Retractable purge mechanism’ updates:

  • We broke one hundred YouTube subscribers!! Yay!!! The new custom YouTube channel name is …. wait for it….. BigBrain3D!! Thank you everyone for making this possible!
  • We’ve flown by 20,000 views and 1,000 downloads on Thingiverse (before those metrics were removed with their site update…)
  • Find a New Mosquito Hotend retractable purge mechanism adapter on Thingiverse here
  • A low height version of the Cage, a longer action arm, and a lower connecting arm, was tested (1000 successful blobs) and is now published on Thingiverse with the suffix ‘Rev B’. Printed kits now include these new parts.  The assembly instructions are different for the low height cage so please pay attention to details on the Thingiverse page. Updates to the connecting arm improve clearance with PINDA probe, and the low height catcher improves clearance with the MK3S cooling fan shroud.
  • There are updated mounts left & right (‘Purge – Cap_Left – Full back – Rev D.stl’ & ‘Purge – Mount_Right – Full back – Rev D.stl’) which extend all the way to the printer frame so that during the automatic Z leveling the Z shaft brackets don’t flex.
  • We received official Prusa Orange filament and now offer that color on the site as a custom color. It’s expensive for us so it will only be provided it as a custom color, never randomly if random color is selected.
  • The Gcode purge script was updated to move the line for turning the fan off to after the blob is cool. This makes subsequent purges more reliable.
  • The Gcode purge script, filament unload, is now updated for default PLA tip shaping.
  • The are new updates to the tip shaping python script on github:

How can You help?

Thank you to everyone who has been helping their fellow makers through our forum, And other online means.

There is one thing we could use your help with. There seems to be an issue with the PrusaSlicer code. In the first few layers there is under extrusion after purging and higher layers have the opposite problem and there is excessive blobbing. Is anyone able to help diagnose this issue?

We’ve created a forum topic to keep the investigation centralized. If you’ve had the same issue, or found a solution to it, will  you please go to the forum topic and add your comments? It will help many people.

That’s all for now.
Happy MultiColor printing!
BigBrain3D =D

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