Roughing

[lik2waterski]

I'm new to aspire. Is it possible to use two roughing passes before switching to a smaller bit? I would like to use a bigger bit to remove a lot of material, then a smaller bit to rough within a few thousandths of finishing.
Travis

[Adrian]

http://forum.vectric.com/viewtopic.php? ... &view=next

[Rcnewcomb]

Be aware that all you are doing is adding more machine time. The purpose of a roughing pass is to avoid breaking the finish pass bit.

The second roughing pass doesn't know about the first roughing pass.

[Leo]

I think of it a little differently maybe.

First toolpath, 3D roughing, big cutter, hog out lots of material really fast.

Second toolpath, 3D finishing, bigger tool than final tool path and smaller than roughing. Large stepover, like 60% or so. Set tool "some" distance higher ("Z") than final pass - maybe .02-.06

Final toolpath, 3D finish, final size cutter, fine stepover (I like 5% - 8%), set tool to final "Z"

I don't do this very often, in fact I've only done it a couple of times. Mostly I just do rough and finish or I just do finish only. Occasionally though, it has worked well for me.

[lik2waterski]

Thank you for the information.

[martin54]

What material are you cutting ? Any particular reason why you would want to do that ? If you are leaving such a thin skin for your final pass then the finishing tool isn't really going to be cutting, more rubbing the surface which is going to generate heat & I doubt it will be enough to remove any tooling marks left by the larger tool step over, certainly not in any kind of wood.

[lik2waterski]

I'm cutting maple. It's a 3D picture. The frame for the picture is 1" high but the center is aprox 2" high.

I thought about glueing it up so the sides of the frame are only slightly over 1". It would be nice to tell aspire that my blank of wood was 1" on the side and the center 6 inch wide was 2" high. Then I wouldn't routering "air". I'm trying to eliminate the machining time. The estimated finish pass is 24 hours.

Thanks for any suggestions
Travis

[Mike-S]

Maybe two tool paths where one starts lower?

[TReischl]

Mr. Travis.

You do not have to rough the entire project with each pass.

You could define boundaries for the deeper areas that slightly overlap the shallower ones.

That way you are not routering air.

BTW, 24 hours is a long time. Just how big is this picture anyhow? If it is a really big picture you might want to think about using a bigger ball nose mill. Big pictures are intended to be viewed from a distance so no one gets up close and looks at tiny details.

You might want to look at the video posted here of a machine burning down that was left unattended. Hopefully you are breaking that project down into pieces.

[TReischl]

Just a further tip:

If you create a bitmap from the model you can then use the trace bitmap function to find various areas of similar depth to make the process of creating boundaries much easier. Then you can just offset those boundaries to get the overlap.

I recommend that you cut the shallower areas first, then the deeper ones.

One other weird thing you can do is actually use the finish routine to rough out the model. That takes a bit of conniving in terms of fooling the machine as to the Z zero location. But it works well. Just make sure that your stepover vs depth of cut makes sense.

Lots of way to use what is in the software to speed things up quite a bit.

BTW, most of this is not worth the effort for smaller jobs.

[lik2waterski]

Thank you all for the addition comments. I tried to attach the file in the hopes if someone saw it they might be able to give me the steps they would use. However, the file was too large. I'll try some of the steps mentioned above. Thanks everyone for the help.
Travis

[highpockets]

Try zipping the file or put it on dropbox or googledrive and post the link

[lik2waterski]

https://www.dropbox.com/s/iopycok852wn7 ... crv3d?dl=0