Freehand + CNC Pen Plotter

While we’ve proven our nascent CNC could home and respond to individual hand-typed G-Code commands, we have yet to run more than a single line at a time. We’ve just bolted it down to a table but before we put too much effort into more hardware, it seemed like a good idea to make sure the software side is capable of a multi-line program.

Emily found a short snippet of G-Code that purports to draw a smiley face with a pen plotter. It is a great introduction to G-Code, showing us a basic way to start and stop the machine. Curiously, there is no Z-axis motion at all. It uses spindle motor commands to communicate “drawing” (M3 = spindle on) and “not drawing” (M5 = spindle off.)

T1 M6
G90 G94
G54 X0 Y0
G00 X0 Y0
G00 X-25 Y20
G91 X-10
G02 X10 Y-10 I10 J0 F200 M3
G02 X-10 Y10 I0 J10;
G90 G00 M5 X0 Y0;
G00 X25 Y20
G91 X-10
G02 X10 Y-10 I10 J0 F200M3
G02 X-10 Y10 I0 J10;
G90 G00 M5 X0 Y0;
G00 X40 Y0
G02 X-40 Y0 I-40 J0 F200 M3
G90 G00 M5 X-55 Y0;
G02 X0 Y-55 I55 J0 F200 M3
G02 X-55 Y0 I0 J55

Reading through this, I could see the XY coordinates are all around (0,0) so the center of this smiley face should be at the origin. Other than that, I have no idea. And since we haven’t built our Z-axis yet, Emily volunteered to be a human Z-axis. We sent this snippet of G-Code (some hiccups along the way) and our reward at the end of this work session was an artistic collaboration between human and machine.

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