Vcarve issues

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Michael Moore
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Vcarve issues

Post by Michael Moore »

I'm having my first try at using Vcarve and I'm having some problems.

I'm doing a small plaque (about 7" x 8") for a friend's off-road motorcycle event that will be used as a foundry pattern. There is text (no problems) and artwork with fairly complex outlines, and there are multiple islands in the artwork to boot. Total DOC is .2". I've already had to modify his artwork to make it more machining friendly, but I'm still not able to get it to fully machine.

I could really use a Vcarve re-rough operation. There are some relatively large flat areas at the bottom level of cut. I'd prefer to rough them with a .25 then a .125 and finally a .062" cutter instead of removing it all with the smallest cutter. But if I can get it to do two or three Vcarve rough MOPS in a row (it seems to often not like to have that done) the second and third re-roughs aren't aware of the first cut and there is a lot of wasted time cutting air.

I've tried to offset the curves to give me a far border for the Vcarve tool (a more constrained pocket for it to work in) but that loses a lot of detail, and the roughing operation also wants to cut air on the far side that is over area that might have already been roughed with a regular pocketing op.

It would be useful to have the ability to set different stock amounts for the walls and the floor. If I go to zero stock to clear as much of the floor as possible the roughing cutter cuts too deep on the wall and when the Vcarve operation is done it exposes gouges. I need to leave .003" on the walls to avoid the gouges (even with tolerances set to ten-thousandths) and that means that the Vcarve tool at full depth cuts lower than the floor + .003". I watched a video of a BobCAD/CAM demo and it looks like they offer separate stock settings for floor and wall so it appears it can be done. Hopefully that tweak is already in progress for VM. Some of the 3D ops have a "clear flat" option but in Vcarve that seems to be a "clear top" and I want to "clear floor".

I'm also finding that there are spots where Vcarve rough skips a level, but it may do that in one pocket and not in another. Or it will do a small section of a pocket that has a constricted opening to the rest of the pocket at the full depth, but the much larger portion of the pocket only went down to bottom - 1 on the levels. The latter happened in the upper right quadrant -- the highest section between the front wheel and the sun machined at full depth but that big flat area between the sun/wheel/mountain top/right border is at the next higher cut level. If anything I would have expected it to be the other way around with the relatively wide-open area going to the bottom. Well, it would be the bottom if I weren't having to leave .003" there to avoid the gouges on the walls.

Since this is all done with the 2D curves at the surface I've only got simulation 3D geometry, so I can't do a Vcarve final and then extract the curve at the bottom of the cut to use for a control region. I can laboriously trace over the simulation in the top viewport to try and outline the area that needs that extra .003" removed, but I can't do it accurately enough to match the bottom of the Vcarve cut. And since there is no actual geometry at the bottom of the cut I can't do anything like pencil tracing to clean up the messy spots.

The curves are too complex for Rhino to extrude them as drafted solids so I can't do this as a 3D operation without getting a "self-intersecting curve" warning on the extrusion, which if ignored gives me weird results that I have to undo.

In the screen cap you can see inside corners that aren't cleaned. Some of those are cut on one or more sides by the Vcarve tool with an arc on the other side where the roughing tool couldn't get into the corner. Pencil tracing with a small ball mill seems like it would be ideal if I could figure out how to do it with only simulation geometry there.

I'm getting 90-95% of what I want, but the unfinished bits are sucking up an awful lot of time as I try to think "how can I clean that up when I've not got any geometry to work with?"

I'll email the file in to support tomorrow after I take some screen captures so I can add text/arrows to point out problem areas. I posted in the forum because someone may have run into these issues and have some ideas on how to fix them (there must be people who use Vcarve a lot - signmakers etc), and if I'm having problems then other people might be having them too, so suggestions posted here might help someone else.

thanks,
Michael
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MecSoft Support
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Re: Vcarve issues

Post by MecSoft Support »

We have made a note of this to our enhancement list.
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