3D Printer (Thesus)

Thesus is made from an Ender 3 V2 and a bunch of stuff that was lying around.

This is the main 3d printer for the space, situated next to the lab computer. It runs Klipper, a 3rd party firmware that allows for print monitoring over the LAN as well as other features. To access it, connect to the LAN and go to mainsail.local

PrusaSlicer profile: thesus_config.ini

The main lab PC already has PrusaSlicer set up with the config, but if you want to use it on your own device then download the PrusaSlicer profile and import the config bundle into PrusaSlicer (File > Import > Import Config Bundle).

Import the model you want to slice by dragging and dropping it into the window. Click slice in the bottom right corner to slice the model (don't forget to modify the print settings where necessary!) and click “Upload and print”. If this doesn't work, you can manually export the gcode and upload it to the printer.

Remember, this config only imports default settings for the printer for PLA, PETG and TPU - they may need tweaking for your part!

You should monitor the print status on mainsail.local and ensure it doesn't encounter errors. It's a good idea to watch the first layer go down to make sure the rest of the print is likely to work.

Always make sure the bed is clear before starting a print!

The printer is controlled by a Pi 3 with a display that connects over a USB cable. It can be managed using the display, but you still need to upload prints via mainsail.local. Do not disconnect it from the printer or it cannot function! If it says on boot that it couldn't connect to the printer, retry one or two times until it works.

The printer uses a CoreXY kinematics system, meaning that two stepper motors drive both the X and Y axis to achieve a higher acceleration and print velocity. It is mostly based on the Duender design.

It also uses two mainboards, an SKR Mini E3 V3 and a Creality 4.2.2. The Creality mainboard runs all the Z steppers and the BLTouch probe, and the SKR Mini E3 V3 runs everything else. As a result, there is a USB 2.0 hub inside the electronics enclosure that splits the USB connection between the two boards. The Creality board connects directly with a Micro USB connector, and the SKR board connects to a CH340 serial adapter instead of the onboard Micro USB connector (because I accidentally broke one of the 27(?) ohm resistors on one of the USB data lines).

The toolhead has an LDO Orbiter V2 extruder with a 115w TriangleLabs CHC Pro hotend. It can push a lot of filament, so the main bottleneck for more speed are the stock Creality steppers and the v rollers.

The bed sheet is double sided, one being textured and the other being smooth. The smooth side has better adhesion, but this is generally too much for sticky filaments like PETG and TPU and should not be used with them.

The printer uses three point Z tilting to try and automatically tram the bed. It does this on every home, and may do more than one round of correction if necessary. Before each print, it will also do a heightmap of the printing area to compensate for the natural warping the bed has. This adds time to prints, but makes it far more likely a print is successful without having to manually correct the bed. Because of this, you do not need to tell the printer to do a heightmap and I strongly recommend not touching the bed lead screws at all.

If prints still aren’t sticking, clean the bed with isopropyl alcohol. Do not use acetone as this will destroy the print surface and do not use glue stick for anything other than TPU.

If you want to improve the printer, go for it! There are many aspects which could be upgraded, such as replacing the V rollers with linear rails/rods. If you make firmware changes, please make sure the existing configs are backed up beforehand.