GH hotwire cutter G Code?

Hey guys,

I've been watching videos out there on using grasshopper to generate g-code for 3-axis milling and i was wondering if anyone has used grasshopper to create a g-code for a hotwire foam cutter? I'm currently building a 4 axis hotwire cutter and since rhino is my main program for design, being able to use gh to create a gcode for mach3 would be awesome. If anyone knows anything about this please let me know!

Thanks!

Replies to This Discussion

Permalink Reply by Kyle VK on November 29, 2011 at 9:25am

Sorry for the delayed response, i've been trying to find time to problem solve between classes and thanksgiving break. Right now my main issue seems to be figuring out how to divide the paths unevenly, so that a larger path (x,y) would have a different spacing between points than a smaller path (a,b)...right now they both have the same spacing which causes one path to be fine but the other to be uneven. I have attached a rhino file with a few tweaks to it. On a plus side i have been able to take the gcode from grasshopper into mach3 and get movement, still need to do some tweaking in mach3 though because it seems that the scale is getting lost in translation somewhere.

Attachments:

G-Code Creator.gh, 27 KB
Hotwire Cutter For G-Code 2.3dm, 59 KB

Permalink Reply by John Rousseau on February 29, 2012 at 9:26pm

Mateusz,
I am curious how you would create G02 and G03 output from curves in rhino/grasshopper. I use a CNC that can interpret these commands, but not sure how to create them. G01 are easy for me though, but the file size is much larger this way.
Just curious, cause they elude me, but I do know it needs a center point, radius, direction, length, etc. I could provide an example if you would have time to explain it, thanks!

Permalink Reply by John Rousseau on March 1, 2012 at 8:46am

An example of a curve sequence in code is this for the attached image:

G03 X5.427 Y1.763 I2.427 J1.763
G02 X6. I3. J0.
G02 X-3.618 Y-1.176 I-2. J0.

Attachments:

CurveGH-Code.tiff, 11 KB

Permalink Reply by Mateusz Zwierzycki on March 1, 2012 at 9:30pm

After writing this post 2nd time, I realized this is really simple :D you just have to check curvature for each point on geometry :) if curvature >0 than replace linear movement with curve interpolation. If point has neighbours with same curvature -> it is an arc/circle so make it circular interpolation (dont remember which one G03 or G02 is it)

Exact g code should be worked out personally -> my cnc adds some information about movement like arc radius etc...

Permalink Reply by John Rousseau on September 6, 2012 at 4:44pm

Hi Mateusz,

I know this is a bit older thread, but I'm now trying to get the G02/G03 functionality working and I can figure the logic for the exact g-code I need on line by line (curve by curve) calculations fine now. (Start point, Center point, etc)

But I'm having problems figuring the logic of which sections of the series of curves are lines vs. arcs so they can be separated and formatted properly.

Including which curves are going clockwise (G02) or counter-clockwise (G03) so as to assign the correct G notation. I've been trying the curve analysis functions with no luck, but maybe I'm missing something obvious here.

You mentioned that this is really simple, but do you have any ideas on how to determine the curve type and direction?

Thanks for your thoughts in advanced.

Permalink Reply by Joshua D. Johnson on May 8, 2014 at 8:33am

So What was the end result of this thread?

I've just built a 4 axis with 10' x 12' x 5'z travels and am currently doing a lot of coding by hand. I love Rhino but have similar problems. It'd be nice if there was a way of offsetting curves and pairing them up in the code. I currently have a simple program done with variables in the g-code itself to solve the issue but it doesn't work with curves. :-(

Permalink Reply by Kyle VK on November 29, 2011 at 10:01am

I've also been stuck on how to incorporate a starting point for the paths...