2011-12-29

and it started with... a wooden Mendel

wooden Sells Mendel
This is a wooden RepRap Mendel made from laser-cut plywood. It was built over the course of several months by members of AUGE e.V. Frankfurt and Hackerspace FfM.

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.

it's printing!
The wooden Mendel was then commisioned for printing stuff at the Hobby&Elektronik fair in Stuttgart.

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