Can I use the VI command to cut a Arch in z-plane?

[mike_boller]

Thanks to all for their comments!

I've programmed the toolpath successfully in the .sbp format, but in the wrong plane. I did it with the code because the curves need to have very specific dimensions and I have limited CAD experience (but plenty of programming experience). I think I can use VI and VU to swap if I can't figure out an alternative. (Big thanks to Harold for pointing out the needed VU command.)

I will try using the Flipper to swap a single arch and then modify the .sbp to allow it to cut the different arches along the length.

Thanks again for assistance. I'll give this a try and report back.

By the way, is there any reason that the Shopbot does not have this capability? I remember when I did this last time in G-code it was pretty straight-forward. I defined the start and stop point of the arch in 3-D, the radius of the arc and whether it when the long way or the short way...

Mike

[dana_swift]

Mike if you have programming experience you can program a Z profile that includes compensation for the shape of the bit. I have done that many times and gotten great results.

The fundamental equations you need are:

X^2 + Z^2 = R^2

for a cirle centered at "0,0", so add offsets to move the cut to where you want it.

A simple tool width fix is to subtract the tool radius when cutting "uphill" and add it when going "downhill".

More sophistication is easy to add once you get the idea of how to cut vertical arches and circles.. arches can be ellipses, circles, or bezier cut in the X-Z direction. The shopbot is much more flexible than the toolpath software. When you can write your own you can have anything you want.

Good luck-

D

[garyb]

I haven't run SB code on my SB for sometime but according to shopbottools.com/manufacturing.htm
"ShopBots run from industry-standard G-code or from ShopBot PartFile code"
That being the case run a g-code file just use a G18 to switch to the XZ plane or G19 for the YZ plane

[srwtlc]

Due to the fact that ShopBots can't do an arc in the Z axis without making the arc be small M3 segments, I don't think that a G-code arc in the Z axis (G2 or G3) will convert and work.

If you have an old copy of VectorCam (came with ShopBots back in the day), you can draw the design, break or interpolate the Z arcs and then generate the code. No flipping or changing axis needed. Approaches and departs included.

I keep my copy of Vector installed just for these purposes.

[garyb]

"Due to the fact that ShopBots can't do an arc in the Z axis without making the arc be small M3 segments"

Scott, correct me if wrong but it wouldn't know its in Z. if you ran the g-code as a normal 2d arc in the Y direction then edit the code and put in a g18 then the arc in Y would become an arc in z, whatever the y output reads would be carried out in z.

funny you should mention Vector, I still have a copy here that came with my bot, even though I stopped using it in about 2002, 2003 and had never upgraded it I had just received an upgrade notice from Fred Smith last week.

[srwtlc]

True Gary, in theory. As long as the G-code for the Y arc was posted as G1's only (inch post and not an arc_inch post), but the G-code to .sbp converter doesn't recognize a G18/G19, so the axis can't be swapped that way.

If you're running Mach3, then your good to go.

Yeah, I got the same Vector upgrade notice. Since the Vectric products came out, I'm forgetting how to use it. ;-)