Changing the Home point G code

[pjnolan28 0]

I recently bought an glass plate for my Monoprice 10 and I'm having trouble with calibrating my printer to accommodate the new bed. Could someone please tell me how to adjust the Gcode for the homing of the printer? The bed thickness is 3mm. Also if it helps maybe also adjust the gcode for the print. 

[GregValiant 1,251]

The usual problem is that the Z switch is adjusted to where the top of the old build surface was.  You can move the Z switch up 3mm or you can build a shim 3mm thick so the gantry trips the switch at near the height of the new glass bed.

Here is my shim.  It slips over that wheel bolt.  When I want to go back to the magnetic bed I just take the shim off.

 

 

For the Auto-Home command "G28" there isn't really isn't any other option.  The command sends the XYZ to their respective end stop switches.  If your Z switch is too low, and the nozzle is over the bed after homing the X and Y then the Z will definitely crash the nozzle into the bed.

If you Auto-Home and the nozzle doesn't crash the bed then yes, there are gcode commands you can use.  A G92 Z-3.0 right after G28 would tell the printer that the current Z location is -3.0.  If the next line is G1 Z0 then the Z will move up to the level of the glass bed.

You could also adjust your Home Offsets to tell the printer where "0" is.

What you would be doing is creating a situation where the nozzle could crash hard into the glass bed.  My suggestion is to move the switch up or if you can't do that for some reason then make something that will cause the switch to be tripped during Auto-Home.  Then you can manually adjust the bed height to the new Auto-Home Z=0 location.

 

Edited May 9, 2022 by GregValiant