Code to plunge Z gradually and then retract along length of a profile path.

[Wal]

Vectric's Cut 2D does an admirable job of generating 2D tool-paths, but I'm wondering if there's a bit of G-code that's available to add in which will plunge the cutter to a specified Z depth as it travels to it's halfway point along the 2D path and then retracts the cutter as it travels along the second half of the path. I imagine many of the programs that carve letter-forms into wood use this technique, but is the Z-depth explicitly specified in each line as the G-Code is generated, or is it controlled by a clever bit of programming at machine level?



Wal.

[Boyan Silyavski]

Fluting Toolpaths
Vcarve Pro and Aspire have it.

[Wal]

>Vcarve Pro and Aspire have it.

Indeed they do, but I'm not using either of 'em... I was after a manual tweak that I could make to my standard profile code. Any chance you could output me some G-code for a fluted straight and a fluted curved line to see how it's being done? (If you could do examples of a linear and a smooth ramp that would be cool!)

Cheers!

Wal.

[Neale]

Quick answer is that the gcode instruction to cut a straight line (G1) generally has up to three coordinates included. If you are cutting in 2D, then these are the X and Y coordinates to which the tool should move; no Z coordinate so the tool stays at same height. If you want height/depth of cut to vary along the path, then you add a Z coordinate and the motion control software will calculate the tool path so X, Y and Z all vary at the right rate to get to the end point in a straight line. So the answer to your question is that yes, the Z move is part of the generated gcode. Aspire, vCarve, etc, all do this when generating 3D cutting gcode. If you were really keen, I suppose that you could find all straight cutting moves, and edit them to include an intermediate point with lower Z point plus original Z value in the original point. Doesn't sound like an easy job to me! Probably why Cut3D costs rather more than Cut2D...

[Boyan Silyavski]

flute toolpaths.txt 100 mm OD circle, 100mm line and 100mm/10mm arc

Hope that will help

[Wal]

Cheers Neale.

Yeah, I have Cut3D - another excellent piece of software from Vectric - but the way that it generates its cut files isn't exactly practical (and very long-winded) for simply adding a couple of fluted lines to a face.

Heh - I don't fancy scrolling down through thousands of lines of code and manually adjusting z-depths...

Perhaps a G19/G18 arc might be worth exploring?

http://www.cnczone.com/forums/g-code...rc-g-code.html

Hmm, but thinking about it they're in X/Z or Y/Z so anything other than a straight vertical or horizontal line isn't possible...

[Wal]

Cheers Boyan. Much appreciated! As Neale said - new z value on each line, which is what I suspected.

Thanks again!

Wal.

[Rufe0]

Just out of interest why would you want to arc in and out with the Z?

[Wal]

Just out of interest why would you want to arc in and out with the Z?

In my case it was for aesthetics - I was looking at engraving into 3-ply acrylic (black/white/black) with a ball-nose cutter, using this technique would have given me a variation in line thickness along the path. Kinda like this:



Wal.

[Rufe0]

Ok yeah well if its exactly that shape you want to make (spiral) you should learn some gcode, its very simple to do in gcode. Something like

G0 X10 Y10
G2 X20 R5 
G2 X11 R4.5 
G2 X19 R4 
G2 X12 R3.5 
G2 X18 R3 
G2 X13 R2.5 
G2 X17 R2 
G2 X14 R1.5 
G2 X16 R1

Then it would be trivial to add your Z depth.

If you wanted to use code generated by a program its probably going to be 1000s of tiny straight line moves. I could perhaps make a small program for you that will tack on the Z depth but it wouldn't be as good as hand written code.