Having only just finished building my Prusa I3 pro B. I've been thrown in the deep end of learning 3d printing. But it has sort of triggered a bit of OCD in me. In my initial prints I had the common issues, getting the bed level etc. The one that snookered me though was getting the print centered on the bed. In Repetier and other printer management programs I would place the item on the screen and it would seem to show up just about anywhere. Next I used the center button, but it was still not right. So I started looking at the Prusa. I noticed that when I homed on the x-axis that the print head was clean off the side of the print bed. So I tried adding a probe to the x axis like the one on the X using one of the extra bolt holes to install the probe. This didn't really work satisfactorily for me, so I kept looking. Seeing all the stuff about auto bed leveling in the Marlin firmware I did some more digging. It turns out that there is firmware info for setting the bed dimensions!
http://reprap.org/wiki/Configuring_Marl ... Dimensions
Now the tricky part that I initially didn't think about is that you can actually define an axis dimension to a negative number!
So, I fired up Repetier again and hit Home. Once it was at zero I started manually moving the x and y axis and see where the print head was on the bed and what the numbers were saying. I then plugged the coordinates I saw in manual control and entered them into the configuration.h file
Code: Select all
// This is the bed area set to print area including a negative offset for homing origin.
// Does not require M206 and indeed required M206 to be clear.
#define X_MAX_POS 200
#define X_MIN_POS -20
#define Y_MAX_POS 170
#define Y_MIN_POS -20
#define Z_MAX_POS 130
#define Z_MIN_POS 0
I updated the firmware, fired up Repetier imported and centered a test shape. Before you fire it up you need to realize that you should now remove any Bed Left or Bed Front settings you have in the Slic3r printer settings. All you have to worry about is the "Max settings" on that page leaving the print area at your max. In my case it was 200x200x180. There may be a little more Z available but I'm not worried about it right now.
The point too all this is that the printer itself will now know where the zero point is on the print bed rather than trying to do it in the software.
Just sharing what a newbie has learned.
