Where do you adjust the plunge rate in Gcode?

We have a .NC code that is super slow when doing a drill operation. I can’t find where to change this setting. we are using Vcarve Pro to generate the .NC code.

I don’t use vcarve pro, but googling some images suggest you set that value for each tool. So go to tool info for each tool and you should see a plunge rate value in the dialog box.


Thanks. The tool in vCarve is set at .5 inch per second. I don’t know why the settings are moving to the Maslow. It’s moving about 1mm / 5 seconds

Is this a stock design maslow with stock z-axis kit?

Your 12mm/0.5" per minute may be the maximum Z feedrate. I couldn’t find the maximum rate discussed in the forum, but it’s excruciatingly slow, much slower than the other axes. It’s a high torque low speed motor. It’s simulating fingers turning a knob in a mechanism that wasn’t designed for CNC speeds.

Hopefully @bar or somebody who’s measured it will let us know how fast it’ll go

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For an idea of how fast the z axis can go at it’s highest speed, run ‘Test Motors’ and watch it move. This test moves each motor at full speed, without software limits.

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Thanks. If I could get it to move at the speed it moves when you are setting the Zero, that would be great. There has to be a way to adjust this.

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When I test the motors, they move at a speed at which would be acceptable for me if we could get the z to move like the test in the program.

Post the first 20 or so lines of the gcode… maybe we can figure out what’s going on from it.

This is the feed rate (in the gcode, it’s the number after the F in the Z

The value that limits the z-axis speed is found in Settings.cpp of the firmware, on line ~86 - maxZRPM. It is currently declared as 12.6.
You can try different values. Be advised, this setting may have strange results in gcode files that do coordinated x-y-z movements :wink:
The easy way to play with this setting is to program one of the GC macros to send the value.
would send the default value. With a meter on the bench,
$18=20.0 seemed to cause the drive voltage to maximum, higher values didn’t seem to make a difference.
My sequence was to change the macro, use the macro button to send it, use the Z-axis panel to test it.
Let us know what your find :grinning:

Once you settle on a $18 value, you can try values for F (feedrate) in your gcode file as @dlang suggests.

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Thanks. I searched the Gcode and there is no reference to the letter “f” in the entire file.

Here is the first 30 Lines

N0 G0 X0.0000 Y0.0000 Z0.7500
N1 G0 X-4.2426 Y4.2426 Z0.2510
N2 G1 X-4.2426 Y4.2426 Z-0.7500
N3 G0 X-4.2426 Y4.2426 Z0.2510
N4 G0 X-4.9497 Y4.9497 Z0.2510
N5 G1 X-4.9497 Y4.9497 Z-0.7500
N6 G0 X-4.9497 Y4.9497 Z0.2510
N7 G0 X-7.2565 Y-3.9158 Z0.2510
N8 G1 X-7.2565 Y-3.9158 Z-0.7500
N9 G0 X-7.2565 Y-3.9158 Z0.2510
N10 G0 X-3.9158 Y-7.2564 Z0.2510
N11 G1 X-3.9158 Y-7.2564 Z-0.7500
N12 G0 X-3.9158 Y-7.2564 Z0.2510
N13 G0 X3.9159 Y-7.2564 Z0.2510
N14 G1 X3.9159 Y-7.2564 Z-0.7500
N15 G0 X3.9159 Y-7.2564 Z0.2510
N16 G0 X7.2565 Y-3.9158 Z0.2510
N17 G1 X7.2565 Y-3.9158 Z-0.7500
N18 G0 X7.2565 Y-3.9158 Z0.2510
N19 G0 X4.2427 Y4.2426 Z0.2510
N20 G1 X4.2427 Y4.2426 Z-0.7500
N21 G0 X4.2427 Y4.2426 Z0.2510
N22 G0 X4.9498 Y4.9497 Z0.2510
N23 G1 X4.9498 Y4.9497 Z-0.7500
N24 G0 X4.9498 Y4.9497 Z0.2510
N25 G0 X0.0025 Y-1.3750 Z0.2510
N26 G1 X0.0025 Y-1.3750 Z-0.1875
N27 G1 X0.0000 Y-1.3750 Z-0.1875
N28 G1 X-0.0355 Y-1.3745 Z-0.1875

So it’s taking about 35+ mins to drill one 3/4 deep hole. :frowning:

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@madgrizzle - Yes - Stock design w/ Stock Z-axis.

Thank you @blurfl
I appreciate your help. Unfortunately, I’m not that technical and don’t even know where to begin to modify the settings.cpp firmware file (latest as of Jan 1). I don’t even see this file on my PC when i search for it.

Here’s the first few lines of something from makercam. It’s a profile cut and does passes at 0.05 depth increments. Seems like Vcarve Pro is missing somethings (not all lines below are recognized by Maslow).

(Generated by PartKam Version 0.05)
G20 G90 G40
(profile 1)
G0 Z0.5
T0 M6
G0 X9.375 Y8.125
G1 Z-0.05 F30

The F30 is 30 inches per minute…

G20 = programming in inches
G0 = rapid position
G1 = linear interpolation.

Looking into the Gcode file, it looks like some better settings choices in the V-carve program might be a help here. What is the bit size you’ve told V-carve to use? What is the hole size you want to drill? Should they be the same? It looks like V-carve is drilling holes .75" deep then moving 0.0001" and doing the same again. That doesn’t seem right…:thinking:

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We are plunge drilling 1/4" holes to a depth of 3/4"
The bit we are using is a 1/4 spiral cut end mill.

Try changing thhe line
N0 G0 X0.0000 Y0.0000 Z0.7500
to be
N0 G0 X0.0000 Y0.0000 Z0.7500 F40

That will tell the firmware to use the maximum travel rate. How big is the file?

@blurfl - Same result. The file size is 111kb