Z axis move on Job Start is too much

At Job Start, the Z axis rises too much and hits the end of travel (no limit switch). My machine is a Genmitsu 3018 PRO.

Here is a copy of the G-code segment right at the start of the job:

;MillMage Pro 0.8.00-RC-13 @ c84582b Qt6.5.7
;Custom GCode device profile, absolute coords
;Bounds: X117.761 Y-96.777 to X117.761 Y-96.777
;Project Units: Metric
;Safe Retract = 5
;Stock Thickness: 20
;Z Zero: Top
;Workpiece origin is at the Top Left
G00 G17 G40 G21;Restore metric mode
G54
G90;Restore absolute mode
G0 Z20
G90;Restore absolute mode
G21;Restore metric mode
;Drill @ 6000 mm/min, 8000 RPMs

The Z-axis has about 38mm travel and the stock thickness is 20mm leaving about 18mm before topping out the spindle.

I would only like it to rise 5 from the top of the workpiece when starting the job. Where can I find this setting in MM?

Thanks for your help.

I think you set it at the beginning of the project, MM asks for some settings:

I don’t know where to access those settings after the project has been edited. I never needed it before :slight_smile: Edit: Check the File menu. There is an edit function for the project setup.

The settings you mention are in the Project Setup: Beginners Setup. All mine are set to 5mm.

Then maybe you set the first steps in that configuration incorrectly. It looks like you set the thickness to 20mm but the zero position at the bottom. Try to set the zero position at the top of the material. Edit: looking at the comments in the gcode, it doesn’t look like that. It seems everything is set like I’d also do it :slight_smile:

This is incorrect. Set it to bottom left. Then the head will only move 5mm up. Just tested with my setup.

;MillMage Core 0.8.00-RC-13 @ c84582b Qt6.5.7
;Custom GCode device profile, absolute coords
;Bounds: X25.972 Y36.972 to X51.028 Y60.028
;Project Units: Metric
;Safe Retract = 5
;Stock Thickness: 20
;Z Zero: Top
;Workpiece origin is at the Bottom Left
G00 G17 G40 G21;Restore metric mode
G54

G90;Restore absolute mode
G0 Z5
G90;Restore absolute mode
;Pocket @ 600 mm/min, 1000 RPMs

That did not compute!

Changing the Home/Origin position affects Zaxis travel?

I cannot imagine running a CNC without limit switches. I added them to my 3018 Pro, but I think the new machines include them.

I was looking at this last night and tested it at top left and it did not do that for me, so I’m curious as to whether there is some other setting affecting this…

;MillMage Core 0.8.00-RC-13 @ c84582b Qt6.5.7
;Custom GCode device profile, absolute coords
;Bounds: X42 Y-43 to X42 Y-43
;Project Units: Metric
;Safe Retract = 5
;Stock Thickness: 20
;Z Zero: Top
;Workpiece origin is at the Top Left
G00 G17 G40 G21;Restore metric mode
G54

G90;Restore absolute mode
G0 Z5
G90;Restore absolute mode

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I am using a 318 also,….Have you calibrated the Z axis ? $122=385.

This is the Accel setting. $102 is the Zsteps per mm, and my 3018 is 800.

Ok, Perhaps I got them mixed up, regardless when I entered that I wanted 25mm of movement, I was actually getting about 50-60mm causing the stepper to stall. Example, I moved Z to bottom of travel and I would inter the 25 mm movement. It was moving all the way to the top of the z axiis travel..

After the calibration I can enter a given amount and that is what the z axis moves…up or down.

2 Likes

Yes. I Zero the Z-axis every time I start a job.