Printer doing well, BUT??

[Bob]

Hello all. Pretty new here. Been doing a lot of lurking.

I have a Prusa mendel, homemade. Using Marlin, with auto bed leveling, latest version and Pronterface. Really like Repetier better but can't get it to work right.

My prints are better now than they have ever been. However, I can't get them to print in the center of the bed. Everything prints on the bottom 1/3 of the bed. That's fine for little stuff, but larger items print partly off the bed. I know it must have something to do with my offsets, but have tried various values to no avail. Offset on Y axis from hot end to leveling probe is 60mm. At 60 offset it prints to the bottom of the bed. At 40 it's even worse. At 80 the bed slams into the frame at the top. Just kinda lost here.

Also, when I home all axis the Y creeps forward as the z raises to begin it's homing. I have z set to raise 15mm before homing to clear some obstacles.

Could you "3D Printmasters" offer some insight to my problems? What more into do you need?

[3dkarma]

The only thing that springs to mind is steps per mm on the Y axis. Are your prints coming out to scale?

[Bob]

yes, prints are to scale. thanks for your reply.

[tpete61]

You might want to make sure your bed size is correct in your software, it may have a default size like 200X200 and your bed is actually a different size.

[Bob]

Thanks tpete61, but that's not it either. Bed size is right.

[Davo]

Check your custom gcode. Our gcode usually has these three lines up around line 18 or so:

G28 X0 Y0 ; home X and Y
G0 X0 Y0 ; move to desired origin
G92 X0 Y0 ; reset origin: X and Y

If that was changed, like below, all your prints would be offset:

G28 X0 Y0 ; home X and Y
G0 X0 Y100 ; move to desired origin
G92 X0 Y0 ; reset origin: X and Y

[Bob]

Thanks Davo. I'm just confuse about this offset thing. My probe is 59mm behind my extruder. Just can't get it any closer.
My start code is.
G28 X0 Y0
G0 Y50 ; To get the probe back on the bed
G28 Z0 ; To home Z
G29
But, I then run out of bed on G29. I don't know what's up with my mind. Just can't get around all this.
Many thanks for your response. Haven't had much luck solving this and some other problems also.

[Davo]

You will probably get better advice from a Prusa user, I'm afraid. I'm not familiar with your printer.

[Bob]

Thanks Davo.