sheetcam.com

Hello all,

I am with a group of university students and for our capstone project we are making a custom CNC tube notcher (rotary plasma cutter). The tubes to be cut are for our Baja SAE vehicle's roll-cage. We have some light CNC experience, but we would really appreciate it if someone could point us in the right direction for what we are trying to do for our machine, so please excuse the ignorance that I am sure is about to follow.

We are intending to use SheetCam with the rotary plasma plugin, and control the machine via Mach4 Hobby through an Ethernet SmoothStepper if it matters. Our current tube workspace length is ~20" which is enough room to cut most of the stuff we need too, but what we'd really like to try to do is have the machine be able to cut arbitrarily long tubes by doing the following:

1. The machine cuts the first side of the tube
2. The tube is manually pushed through the machine, with a rotary encoder used to track the displacement.
3. The machine cuts the second end of the tube after accounting for any

Is this just a matter of writing/editing a custom post processor? Are there other considerations we need to make? How much of this problem is dealt with within SheetCam vs custom edits we need to make in Mach4?

Obligatory we aren't looking for someone to do any grunt work for us, we'd just appreciate a little bit of handholding to get us set off in the right direction.

Cheers,
Nathaniel

You can't really do that in a post. The only way I can think of is to draw the ends of the tubes closer together. Say your tube is 10" too long to fit. In the drawing you send to SheetCam move one end up by 10" and put it on a different layer. You can then cut one end, manually index 10" then cut the other layer.

Les, Thanks for the response!

With the method you described, would you just get the machine to enter into the 'repositioning sub-routine' between each layer? Is that something I would put into a post-processor or how is that accomplished?

Thanks for your help!

There are no chnages needed to the post. Use the 'Insert code' operation to insert a M0 stop command into the g-code. You want to end up with the following operations:
First end cut
insert code with 'M1'
Second end cut

When you run the code it will cut the first end then stop and wait for you to manually reposition the tube. You can then press cycle start to continue with the second cut.