Question Cutting Plastazote with Donek drag knife

Hi all,

Thought I'd share something a bit different here - some pics of the 2mm LD33 Plastazote foam I'm cutting with my SC840 and Donek D4 dragknife, both supplied by the excellent Rory of StoneyCNC, whose support in getting everything up and running has been absolutely invaluable!



I'm cutting three different shapes into 2mm Plastazote to stack to make a 6mm insert for a CD-like plastic case. The Donek D4 does an excellent job running at 3000 mm/min. The foam comes in long rolls, which I'm securing for cutting with a CNC-Step vacuum table. It took a while to get the parameters (cut depth, swivel depth for the corner actions etc.) right, because the table is not really flat - it has a slight bow to it (front and back) but it's working well enough.





The product incidentally is a very high-quality crystal glass nailfile for guitarists, made for me in the Czech Republic. Prior to the arrival of my Stepcraft, I was cutting this packaging individually by hand with an x-acto knife!!




Cheers,
David

Thumbs up!
Amazing results

What did you use for a program to setup the G Code for the Donek? Vectric stuff? And what did you use for values (offset, etc)? We have one here and can not get it to work with the dragknife gadget in Vectric Cut2D pro.

Thank you

stepcraft-usa wrote: What did you use for a program to setup the G Code for the Donek? Vectric stuff? And what did you use for values (offset, etc)? We have one here and can not get it to work with the dragknife gadget in Vectric Cut2D pro.

Thank you

I think the key parameter is the acceleration. By using a low value you give enough time for the knife to rotate. It's a drag knife after all, it requires motion to align.

By low I mean about 100mm/sec for example.

I use Sheetcam to generate my toolpaths - never used any of the Vectric stuff. This swivels the knife on the corners, which enables sharp corners etc.

I have my 840 well tuned, and run it at 5000mm/min on X and Y axes when cutting with the Donek. Obviously it runs slower when swivelling, as UCCNC applies acceleration to the toolpaths.

The offsets for the various Donek versions are here http://donektools.com/compare-drag-knife-models/ - mine is a D4 so I use 4mm offset.

Cheers,
David