Recompiling Mendel GEN6 firmware.

I downloaded the GEN6 source code and the Arduino + Sanguino package from Medel-parts.
Unziped the source code folder FiveD_GCode_Interpreter and the arduino-0018 folder.

Before we star the development environment we need to power up the Mendel and connect the USB cable.

In the arduino-0018 folder I started arduino.exe From the "File->Open" menu I opened the file "FiveD_GCode_Interpreter.pde" in the FiveD_GCode_Interpreter folder, and it loaded into a new window.

To increase the amount of steps/mm we need to find the definition of E0_STEPS_PER_MM in the file configuration.h

It was defined to be 20.2 and we need to increase this for Adrian's geared extruder by approximately 38 times (to 767.6). After some research I found that someone else, after some tests, had to change this to 780.6.

So I changed the line to: #define E0_STEPS_PER_MM 780.6

Before we compile and upload our modified firmware, be sure to select the right COM port under "Tools->serial port" and the platform under "Tools->Board" to "Sanguino".

Press the upload button and it will hopefully compile and upload the new firmware.

I printed my test cube again again and this time it looked extremely promising...

However, after a while the the pressure seems to go down  and  the last layers was only small dribbles of plastic. I suspect it has to do with the filament retraction when the nozzle moves to a new position. Time to elaborate with the gear lash...

Software and parameters

I Started to use the RepSnapper software and loaded some STL files, converted to GCode and printed at 200c.
To my disappointment it looked like crap! Also the Y position seemed to shift for each layer resulting in the leaning tower of pisa.

But when I wrote a GCode program manually and moved the Y position fort and back, it always came back to the same spot. So I was suspecting that RepSnappers conversion to GCode wasn't that accurate.

I tried to use Skeinforge for the GCode generation and the Y position became steady again, so it must have been some problem in RepSnapper.

Skeinforge looks like a technician puking buttons after a really bad meal in a foreign country. For a beginner it just looks pointless to even TRY fiddling with the parameters.

I just figured out that someone else must have done the same thing before me so I googled and found a setting made for a Mendel Gen6 in the Mendel-part forum.

The result looked better but now it seems like it is far to little plastic extruded.

It came to my mind that This settings are probably not for Adrian's Geared extruder that requires (according to my little calculation) 38 times more steps/mm. When I extrude 100mm it only does around 2.6mm, so 100/2.6 = 37.04 times more plastic is needed.

After some reading on various forums someone has changed the FW


#define E0_STEPS_PER_MM 20.2


to


#define E0_STEPS_PER_MM 765


The question naturally comes to my mind: Why doesn't Camiel deliver a FW that works with the extruder he put in his own Mendel kit (Adrian's geared Extruder)?


Anyway, I have not confirmed yet that this is the case with my FW, but everything points into that direction...
(If anyone knows a way to adjust this in Skeinforge, please drop a comment)