Crown drawing in the air

I’ve finished my MPCNC, and I can control it manually with Repetier and everything seems to be moving the right way. But when I run the crown it picks up and moves to the middle of the bed and then starts drawing in the air.

before running the program I move the gantry over to the left side and about middle of the y axis, and I bring the pen (z axis) to just a little bit above the paper.

what might I be doing wrong? I created a simple file in Fusion that is a rectangle in a circle in a square, that I then processed through Estlcam and it is doing the same thing



Either restart your board just before you start or use G92 x0 y0 zo as the first line of gcode.

1 Like

I’m sorry but I’m new to all this looking at the code I see on line 5 there is a G90. Should I replace that with G92 x0 y0 z0, and these are zeros right not “oh”.

also moving forward will using this code make the machine start where I want it to? What I’m trying to understand is how I’m going to get this machine up and running.

Did Estlcam spit out the code wrong? I’m feeling pretty confused at where to go from here in trying to get the machine to do simple projects, without learning how to program gcode, I’m not sure how I will ever get it to do a complex 3D carve.?


This page is a good resource, you should consider bookmarking it.


G90 sets the machine to absolute positioning mode. Meaning it will register a command telling it to go 90 x and 45 y to a point located at (90, 45)

The opposite of this is G91, relative positioning. In this mode, issuing it the SAME move command would make it go to wherever it is currently positioned in (x, y) PLUS whatever x/y/z values you feed it. So, if your machine is located at (5, 5) and it’s in relative positioning mode, and you send it G0 x45 y45 it would go to the x, y position (50, 50)


What g92 does is set the current position to whatever values you give it. So, G92 X0 Y0 Z0 would set the X, Y, and Z to zero. Then you could say “G0 x1 y1 z1” and the machine would move to the right one unit (in our case, 1 millimeter), up one unit, and lift the z axis 1 unit.

Basically what you’re doing is moving the TIP of your tool to wherever you set your zero point/origin to in the CAM software (with the crown g-code, it would be the bottom left corner, with the tip of the pen just touching the paper) and then set that as your zero point by typing G92 x0 y0 z0. You could accomplish the same thing by simply moving the machine to that point and turning it off and back on once it is in that position then immediately running the program without moving the head any more.


And yes, those are zeros.


Sorry if that didn’t make sense, I’m on several benadryl and a bit loopy :stuck_out_tongue:


It makes sense to a degree, I think I just have a big learning curve to manage!

but just to make sure, I replace the G90 code with the G92 code?

also I set the printer shape in Repetier to the size of my work bed, so is Repetier taking the gcode and trying to move the router to wherever the coordinates would be relative to the size of the bed I told it?

if that makes sense?!



Thank you Ryan and Tim! Woot woot!! (2.78 MB)

1 Like