Hello,
i am currently working in a group project with the goal to develop a cnc cutter for carbon fibre. Unfortunately noone in our group has any experience with that.
Right now we plan to use mach3 paired with the triple beast (http://benezan-electronics.de/shop/product_info.php?cPath=8&products_id=61&language=en&osCsid=003f441d590d4e843158bf069d89ae0a). Since we want to use a rotatory blade for our cutter we need to change the g-code created out of a .cax-file in order to align the blade with the cut direction and to be able to cut corners. So we are right now looking for postprocessors which can do that and further more are compatible with the software. A postprocessor which was recommended to us is for example aspire, because it has the option to generate g-code for a drag-blade. Are there other postprocessors which have the same function and are they compatible with the software and the hardware we plan to use?

Thanks in advance for every answer.

Hi Arctic Monkey,

Mach3 can be operated in Tangential mode (see Settings page and also Mach3 manual) and the blade will follow an outline toolpath.
There is however a problem regarding G2 & G3 commands (where the blade may rotate whilst within the work) and a workaround for this is to create a ‘lead-in’ (within your CAD/CAM), which has the same radius as the circle being cut. It may sound a bit fiddly but it’s easy enough once you get the hang of it.

Hope this helps with your project.

Tweakie.

Thanks for your answer tweakie. Could you please elaborate how this workaround works and what problem it avoids?
I found in the manual that instead of G2 or G3 the curves must be programmed as a set of G1 moves and in another thread I dug up the solved the problem by converting the g2 or g3 moves into g1 lines. Basically they interpolated the curve with a lot of short lines. How can i do that myself and how does your solution differ from that?

As for the tangential mode it seems i only need to set up the A axis as a rotary axis and activate tangential mode.

Hi Arctic Monkey,

Most CAM software allows the Gcode for curves to be created from either arc's or arctangent's (G2/G3 or G1) where it is just a case of selecting the appropriate post processor within the CAD software before generating the Gcode.

The Tangential problem has been with Mach3 for many years now and it is unlikely to ever be resolved now that Mach4 is coming on stream. By creating a CAD/CAM 'lead-in' for any G2/G3 circles the blade direction is set during this lead-in whilst the blade is clear of the work and by making the lead-in have the same radius as the circle being cut the work is not spoiled as a result of unwanted cuts. It's difficult to describe this but once you have it working you will understand.

Tweakie.