A few of our large format machines are custom built coreXY style printers utilizing a direct drive extruder system. We have designed our own print heads on these machines and are continually researching and developing new prototypes. In one of our recent modifications, we added a CANBUS EBB36 board to the print head in an effort to reduce the number of wires and resistance affecting the heads allowing for faster print speeds and easier tuning of the overall system. The test bench essentially is itself a 3D printer without any of the axis motors. It has a power supply unit, motherboard, Raspberry Pi, U2C, screen, and a fixture to hold the print head with all the wiring neatly organized to connect all of the components.

The use of the RaspberryPi allows us to connect each printer via Klipper / Fluidd over WiFi and monitor the processes throughout the fleet in our in house management software Formfactories. The U2C board connects between the Raspberry Pi and the EBB36 where signals are sent over just a few wires for all functionality of the tool head, including the extruder motor, heating element, thermistor, cooling fans, adxl accelerometer, bed probe, and the end stop switch.

With this setup, we are now able to build one of our custom tool heads, place it on the bench, flash the proper firmware, assign it’s ID and IP address, and check to see that it is extruding properly, heating up the nozzle correctly, and that the fans are fully functional. Then we can take the tool head over to the machine that it has been assigned to and complete the install. The test bench is also a great addition for troubleshooting print heads that decide not to work properly.

To finish the project, we designed and printed a shroud to cover the components of the test bench and added some led lights to complete the build. Stay tuned for our next article where we design and use fixtures or jigs to assist in our 3D printing endeavors.