I have gotten the 3D metal printer I’ve been building to talk to the computer but as you can see, it’s not yet functional as a printer.

Mechanically, the printer was built according to the specifications here.

At this point I have spent countless hours going over the firmware looking for anything I might have entered wrong, all to no avail. As you can see in the above Youtube video, the printer does respond to some commands entered manually; I can move in X, Y, and Z directions incrementally, but I cannot home the printer, and when I try, it behaves very erratically, ignores the endstops, and will keep going up or down, or else slam against the sides.

The firmware I compiled and uploaded is the Delta-MOST firmware from MTU.¬†When successfully compiled and uploaded, this allows the board to connect to the computer via RepetierHost printer software. I have gone over the firmware line by line many, many times, and can see nothing that might be causing the machine to ignore the endstops, and the fact that the endstops respond correctly to the M119 command makes me suspect that somehow, something in this Geeetch Melzi board is not allowing the signals from the endstops to be conveyed to the motor drivers. (I returned a second board — from SainSmart — which refused to let me upload firmware at all, and they are sending me another one. If I can get it to accept the code and it behaves in the same manner as the Geeetech board, that will, I think, point to the firmware. The Geeetech board also compiles the Marlin software, but the board will then connect to Repetier and do absolutely nothing, so I have been unable to use that.)

Also, when I load an .stl image to run a job with RepetierHost, once I generate the G-code in Slicr and load the job, it again slams around and the effector hits the sides.When I try to connect to Cura, it times out trying to connect when I try to start the autoleveling feature, which means I have to stick with Repetier for now. (All the settings are correct so far as I can tell.)

I have also noticed that the three driver chips seem to get awfully hot after not much use. My theory is that somehow, the board is having trouble communicating back and forth between the endstop circuitry and the stepper motor driver circuitry, but I have no expertise how to test it. I don’t know whether it means anything, but when I Googled the name on the chip — ATMega 1284p au — it is described as 8mhz, but it will only allow me to upload code if (in the Arduino IDE) I designate the board as Mighty 1284p at 16 mhz.

If anyone has the slightest idea what I am talking about and might be able to help, I am all ears.

Regular, normal readers, please forgive this bizarre departure from my standard blog protocol, but I am up against a deadline and feeling the pressure.

And besides, if I can’t occasionally use this blog for my personal stuff, what do I have it for?