Title, This bloody thing has been a thorn in my side for around a year now, Completely stock RepRapGuru Prusa I3 aside from a spool holder i printed to set the spool off the acrylic frame
It's on marlin V1.1.6 (Included FW)
No matter where the limits/origin/etc are set, when you run a print (Specifically from SD, i've seen there may be a bug in marlin that'll melt the 12v green ramps connection if you go over USB instead) it ALWAYS goes to the front left corner off the bed and then starts the print there, causing it to just pour plastic over the edge of the bed.
Base settings they give in the "Config guide" did it, adjusting things off some googling still did it, it's a 200x200 bed with the origin at 100x100
It's leveled perfect, it homes where you'd expect, it just absolutely fails to actually start at the center of the deck no matter what i do
You can try changing the size of your print area to be smaller.
Can you post a gcode file?
Also are you sure that you are in the correct coords (relative or absolute)?
I had an issue once with my mill that the program would set acceleration and jerk settings on its own a few lines after I set them, to values much outside of what the motors could do, and they would be stalled at the origin. could it be that?
I've figured it out, partially, the bed is 200mmx200mm same as my davinci 1.0, but jogging it by 50mm in repetier sends the print head halfway across the bed
So for some reason, it's doubling all commands sent to it for no reason, so a 3mmx3mm print at 100,100 becomes a 6x6 print starting at 200,200 or the far corner of the bed
Drivers are set to the proper VREF and everything, speeds/feeds are all normal in firmware/repetier/Slic3r/Cura i'm stumped.
Round 3, Swapped the whole ramps board assembly to a different one with another set of A4988 drivers, now it works but it can't be leveled properly because the bed holder is acrylic and it's impossible to get it printing on the bed directly or to not shut down to thermal runaway even when it's sitting stable at 235 on the hot end and 70 at the bed.
About to just scrap the whole thing and build another printer out of it's parts with a better design
Live life on the edge and just disable thermal runaway protection lol
also it is pretty much a must to get a mosfet to run a bed with ramps, youll melt those crappy green connectors in no time flat, especially running at 70C
If you do decide to get new drivers, get DRV style or TMC style drivers. they are a lot better than the A4988's
can you just move the limit switch down to print closer? or put another piece of acrylic or glass under or on top of the bet to make it closer
You should not have to double the commands. You adjust the steps per mm settings for the motors of it is not scaled correctly
Also set the home position in the front left of the printer, not the middle. I think marlin doesnt allow the motors to go to negative coords by default
Side note, acrylic is usually not a very good choice to make a printer out of