|wooden Sells Mendel|
While being cut very precisely the plywood changes shape and volume according to temperature and humidity. This means that adjusting the whole system from bearings to zero-points of the axes is imperative before printing. The mechanics of the extruder also showed heavy wear after a few printing sessions.
The electronics used are RepRap Gen3 with serial extruder controller board. Driving the extruder via the second controller over a serial link using non-shielded cabling introduces several sources for malfunction to the system. Furthermore, being controlled over a serial protocol, the extruder produces stalls in movement of the X and Y axis when the main controller needs to wait for the extruder to complete commands.
I solved this via Kliment's excellent Gen3+ that integrates two input channels for thermistors, two MOSFET-driven power outputs and a Pololu Stepper Module (Allegro A4988) onto the main Gen3 electronic board.
|Gen3 electronics with Gen3+ daughtercard and mounted Pololu module|
Running this controller configuration with the Sprinter firmware yields usable results.