No Part Off?

[karossii]

I have down 3 rotary lithos now, 1 of which was a 'successful' carve, and a second which is usable but flawed. Something I just noticed with the last one, which was the first I would consider successful, is that none of them were 'parted off' - I have the diameter of the workpiece set at 3.5", and the part off diameter at 3.313" (106/32 actually). But it didn't even touch the part-off area, there's no marking, and I watched it finish the carving, and it never even tried to part it off. I was expecting a 1/16" or so thick tab left to cut through. Instead I have the full 1/4" pipe wall, and no visual or tactile guide for my hacksaw... here's hoping I can cut it off straight, and have a nice clean edge!

But I would like to know, for the future, why it didn't part it off like it is supposed to? is there a minimum depth before it will do that part-off? If so, what is it?

[bergerud]

There is a forbidden zone at the driving wheel end. The behavior of the firmware is different depending on whether the carve region goes up to the zone or not. I cannot exactly remember the details. Something about whether the carve ramps in and whether it does the over carve at the end. No ramp in or over carve if into the forbidden zone. The part off may also depend on whether the carve region gets into the forbidden zone. I think you have to leave an inch for the zone.

I used the rotary jig as well as my own jig quite a bit while beta testing but have not done much rotary carving since.

[karossii]

I got my carve right up to the visible part-off in the software, but made sure to not actually overlap any of the part-off area. I think it came out to 0.631" from the edge of the workpiece in designer. So you're saying I need to leave even more of a gap than that?

[bergerud]

I am not sure. I thought it was an inch. I may be wrong and/or it might have changed. I should do some research into it.