Where to find z coordinate in G-code for delta printer

Question

I´m currently writing my own firmware for a custom delta printer. Therefore I also need to read G-code from programs like Slic3r. Even with an small example like an cube I´m struggling to find out where the z-coordinate is hidden in the code. Here is a small example of the code.

; generated by Slic3r 1.2.9 on 2017-02-13 at 15:08:01

; external perimeters extrusion width = 0.50mm
; perimeters extrusion width = 0.58mm
; infill extrusion width = 0.58mm
; solid infill extrusion width = 0.58mm
; top infill extrusion width = 0.58mm

M107
M104 S205 ; set temperature
G28 ; home all axes
G1 Z5 F5000 ; lift nozzle

M109 S205 ; wait for temperature to be reached
G21 ; set units to millimeters
G90 ; use absolute coordinates
M82 ; use absolute distances for extrusion
G92 E0
G1 Z0.500 F7800.000
G1 E-2.00000 F2400.00000
G92 E0
G1 X-31.893 Y0.000 F7800.000
G1 E2.00000 F2400.00000
G1 X-31.893 Y-25.001 E3.57871 F1800.000
G1 X-31.496 Y-27.307 E3.72646
G1 X-30.350 Y-29.347 E3.87420
G1 X-28.588 Y-30.886 E4.02194
G1 X-26.413 Y-31.748 E4.16968
G1 X-25.000 Y-31.894 E4.25936
G1 X25.000 Y-31.894 E7.41663
G1 X27.306 Y-31.497 E7.56437
G1 X29.346 Y-30.351 E7.71211 F1800.000
G1 X30.885 Y-28.589 E7.85985
G1 X31.746 Y-26.414 E8.00759
G1 X31.893 Y-25.001 E8.09727
G1 X31.893 Y25.001 E11.25470
G1 X31.496 Y27.307 E11.40244
G1 X30.350 Y29.347 E11.55019
G1 X28.588 Y30.886 E11.69793
G1 X26.413 Y31.748 E11.84567
G1 X25.000 Y31.894 E11.93535
G1 X-25.000 Y31.894 E15.09262
G1 X-27.306 Y31.497 E15.24036
G1 X-29.346 Y30.351 E15.38810
G1 X-30.885 Y28.589 E15.53584
G1 X-31.746 Y26.414 E15.68358
G1 X-31.893 Y25.001 E15.77326
G1 X-31.893 Y0.075 E17.34724
G1 E15.34724 F2400.00000
G92 E0
G1 X-22.715 Y-22.716 F7800.000
G1 E2.00000 F2400.00000
G1 X22.715 Y-22.716 E4.86865 F1800.000
G1 X22.715 Y22.716 E7.73745
G1 X-22.715 Y22.716 E10.60609
G1 X-22.715 Y-22.641 E13.47016
G1 X-23.607 Y-23.609 F7800.000
G1 X23.607 Y-23.609 E16.45155 F1800.000
G1 X23.607 Y23.608 E19.43309
G1 X-23.607 Y23.608 E22.41447
G1 X-23.607 Y-23.534 E25.39128
G1 X-24.500 Y-24.501 F7800.000
G1 X24.500 Y-24.501 E28.48541 F1800.000
G1 X24.500 Y24.501 E31.57969
G1 X-24.500 Y24.501 E34.67382
G1 X-24.500 Y-24.426 E37.76336

Here some configuration details:
G-code flavor: RepRap
Nozzle diameter: 0,5mm

filament
diameter: 3mm

general:
layer height: 0,4 mm
perimeters: 3
solid layers top:3 bottom :3

Here is the full G-code

score 4 · Answer 1 · answered Feb 13 '17 at 16:50

It isn't hidden at all. It's just that the Z-axis position only changes with each layer change, so the Z coordinate is only passed at layer change. On line 17 of your example G-code, it starts the first layer at Z=0.5mm:

G1 Z0.500 F7800.000

The next time you should expect Z to appear is on the next layer.

score 2 · Answer 2 · edited Feb 16 '17 at 21:59

Your included code has a line which reads:

G1 Z0.500

I checked a couple of my G-code files for some of the past prints and I was able to identify the bed movement relative to the layer being printed. My slicer (Simplify3D) provides for the bed to drop during certain movements. I found G1 Z0.600 followed by G1 Z0.850 for one of the layers. When that layer was finished the 0.600 changed to 0.900 and the 0.850 changed to 1.150.

This fit in with the model's layer height of 0.300 mm for that job.

I did not find more G1 Zx.xxx codes in your sample, but a larger file would contain those lines.

Where to find z coordinate in G-code for delta printer

2 Answers2