Need help to modify z-axis travel in Marlin v1.1.9 firmware

Mostly Printed CNC - MPCNC Troubleshooting
1

I aquired my mpcnc from someone and came with a MKS 1.3 controller with Marlin v1.1.9 and it has a pre-set limit for the z-axis to 20mm.

Is it possible for me to increase this limit in the firmware and if so how can I change this.

Thanks!

IMG_20200904_205353
IMG_20200904_2053533120×4160 3.6 MB
IMG_20200904_205511
IMG_20200904_2055113120×4160 3.58 MB

2

20mm length or 20mm/s?

You can’t easily change the machine size from gcode.

3

If your firmware actually has a pre-set limit on Z travel it will be here -

#define Z_MAX_POS 20

That is in Configuration.h around line 1105 (in the version I am looking at…YMMV)

4

You might be able to turn off the limit.

5

20mm lenght travel on the z-axis. I would like to go down lower for milling 3/4" MDF.