Cartesian Creations was recently commissioned to fabricate a giant fossil wombat (Phascolonus sp.). Consisting of over 100 components, including a skull over 400mm long, and a pelvis over 600mm long, this was a challenging series of prints. Initial estimates suggested 12kg of filament and around 1300 hours of printing time.

Phascolonus skull

Having only recently moved interstate, we started with a fairly minimal printing capability, consisting of an older Prusa Mk3+ MMU, and a new Prusa Mk3s+. Both Prusas were upgraded with BNBSX extruders and Vesconite bushings, with the older one having had ~25 km of filament run through it.

The Prusas were used for the bulk of the early printing, but we needed a machine that could print the larger bones in one piece. Printing parts in pieces and glueing them back together is not a fun exercise. A TronXY X5SA Pro was chosen for printing the larger pieces because while it’s a cheap machine, it has a decent frame and rails, and a good mechanical configuration. It was anticipated that most of the electronics and components would be upgraded over time.

Unfortunately, the X5SA had electronic issues out of the box, with a problematic SD card reader. It also had a bowden configuration which was not ideal for complex models with tricky support requirements. After a rapid series of upgrades, initially to get it printing, and then to make it into a reliable workhorse. This printer, nicknamed Regnans after the large swamp gums found in Tasmania, did most of the printing of all the longer ribs and larger fossil pieces. The final configuration of Regnans is:

  • CoreXY, based on an X5SA Pro
  • SKR 1.4 Turbo, 2209 drivers and TFT35 (with sensorless, linear advance, UBL and independant Z)
  • E3D Titan + V6 direct drive
  • Gates Belts and toothed idlers
  • MKS 30A bed Mosfet
  • Meanwell 750W UHP fanless power supply
  • 350 x 350 mm x 6 mm thick ALCA5 Bed with 500W 24V Keenovo heater
  • Graviflex magnetic bed with powdercoated PEI build plate.
  • Build area of 345x325x415 (Expandable to ~450mm in Z if needed)
Regnans, a custom CoreXY 3D printer..

Most of the fossils required pre-processing to make them printable. Many had holes and internal voids and walls too thin to print, common artefacts from CT scanning. The techniques described in my other blog post were used with only a few fossils requiring more work. Fortunately having Regnans join the printing farm meant that only the pelvis needed to be divided into three smaller pieces.

Part way through.

eSun’s Bone White PLA filament was used for all the prints. It’s been a long wait for a filament suitable for these type of prints, but the Bone White is an ideal colour. I can’t wait to see it all assembled.

Completed wombat, with Prusa Mk3 for scale.

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