Pen Plotter & Centroid Post Processor?

[djbeede]

I just created a pen holder for my CNC, but I'm not sure how to make files that work for it.
I find it useful for learning G code without making sawdust, and I see it has artistic potential, but generating tool paths from designs isn't as straight forward as I'd hoped.

I use VcarvePro 11 to create tool path files- There's no option to select a pen rather than a bit. After browsing online, I see it's possible to modify/edit a copy of the Post Processor to comment out all the tool change commands and spindle start speed etc. but I'm not sure how to go about it.

Here's someone who did it for his Next Wave machine. PP editing starts 6min in.


Hoping someone has already figured this out.

[ShawnM]

It is very easy to do. I created a "Sharpie" tool in the Vcarve tool database. Set the diameter of the Sharpie (regular or fine tip) if you want, set a max pass depth of about .03 to .06 or so and a spindle speed of 1 because it cant be zero. Doesn't matter what you set it to because you then need to create a "Sharpie PP" where you remove all spindle M codes. Remove any M3 (and even M5) lines which start and stop the spindle. Remove M6 lines for tool changes. There's a lot more you can remove but if you dont know what you are removing dont do it. Using "profile" tool path just select "on" for machine vectors. This will draw right on the line.

[cnckeith]

right on, Kai made a sail plotting machine with Acorn
here are a few short videos.
his approach is unique with a stepper motor to lift the pen on a slide and the weight is adjusted to give just the right amount of float pressure for the pen to mark well over any uneven surfaces.

https://photos.app.goo.gl/9WPPRqfKp86qEWSt8

https://photos.app.goo.gl/heqjUUCSNnx8U7Ed7

https://photos.app.goo.gl/YDANPHrNgNTf9ffd7

[suntravel]

Not a pen, but a spring loaded mono diamond to scribe on granite.

G-Code from Inkscape with no spindle rotation.



Uwe

[H.C]

The vectric dragknife toolpath is horrible (for dragknife) (a simple contour with a little lead in & extend at the ends works fine)
yes, spindle speed of 1 does the job.

Few weeks ago printed a ER20 Collet to fit a LOKLiK dragknife

[cnckeith]

The vectric dragknife toolpath is horrible (for dragknife) (a simple contour with a little lead in & extend at the ends works fine)
yes, spindle speed of 1 does the job.

Few weeks ago printed a ER20 Collet to fit a LOKLiK dragknife

yeah, you definitely have to use Centroid's G code smoothing with Vectric g code.

[ShawnM]

The vectric dragknife toolpath is horrible (for dragknife) (a simple contour with a little lead in & extend at the ends works fine)
yes, spindle speed of 1 does the job.

Few weeks ago printed a ER20 Collet to fit a LOKLiK dragknife

Are you talking about the Vectric "drag knife toolpath" gadget? I have no issues with it cutting 1/4" EVA foam or cardboard with the Donek drag knife.

https://docs.vectric.com/docs/V9.0/VCar ... lpath.html

[H.C]

Are you talking about the Vectric "drag knife toolpath" gadget? I have no issues with it cutting 1/4" EVA foam or cardboard with the Donek drag knife.

yes the gadget: It randomly set the lead-in inside/outside the curves. Yes you can tweak it, but the next time you select & run. It's again switched.
Much easier with a contour toolpath. No need for smoothing Keith...small stuff works fine. No problem with the cutting part of it
(Loklik knife is very small)

edit: Better explained: https://forum.vectric.com/viewtopic.php?t=40457

[ShawnM]

I've used the contour path and the "drag knife fillet" also to get the same results.