3 tool changes

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3 tool changes

Postby AdPrinter » Wed Jan 27, 2016 12:03 pm

I have been working with MeshCAM Art for several years, and have a constant desire for a 3rd tool path creation.
Specifically,
Primary Roughing Tool (1/4" diameter preferred)
Secondary Roughing Tool (1/8" diameter preferred)
Finishing Tool (1/16" diameter preferred, or even smaller)
My reasoning for this request, is from an artist's viewpoint. One begins a painting, by starting with a large brush to paint the background area of the image. A medium brush, to paint the mid ground area, and a very small brush to paint the details in the foreground. Similarly, to truly be able to do 3D sculpting, this option would accommodate the Primary Roughing Tool removes the bulk of the material, The Secondary Roughing Tool removes material from a more detailed area. And Finally the Finishing Tool would finish up the cut with the very small (and delicate) diameter bit. The software in it's current form (single roughing tool, and single finishing tool) seems very capable of producing the needed tool paths. The problem is in the physical world, tool diameter is the "wall" I keep running into. The 1/4" diameter Roughing bit seems to be the minimum tool size which will successfully remove the bulk of the material during the roughing cuts. And 1/8" diameter Finishing bit seems to be able to handle most of the finishing cuts. However, because it IS 1/8" diameter, some of the carving's detail is lost during tool path generation. Which can only be done with a 1/16" (or even smaller) diameter Finishing Tool bit. Which is almost guaranteed to break, as it attempts to cut the material left by the Roughing cut. Thus the need, for a "3rd Tool" option!
AdPrinter
 
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Re: 3 tool changes

Postby Randy » Thu Jan 28, 2016 9:55 pm

In that case (such as a lithophane) I just do the roughing (with the roughing tool) and finishing (with the fine roughing or rough finishing tool) toolpaths, output them separately, and move the Z zero up by about .010" for the finishing pass, then calculate a finishing pass with the "real" finishing tool, put the Z back down to the proper level and run the final tool. That way (assuming since it's a 3D part and no vertical surfaces and using a ball-end for the fine roughing/ rough finishing tool) only the final finishing tool will touch the finished surface, since a ball-mill tapers up from the "tip" and a straight vertical offset will also create horizontal clearance with the second tool.

Randy
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
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Re: 3 tool changes

Postby AdPrinter » Sat Jan 30, 2016 5:16 am

Randy,
Do not be confused, by what I was referring to here. The type of carving, I AM referring to is actually a 3 dimensional Sculpture. NOT a Lithophane. Think "Statue" type sculpting. If you look at the photo I uploaded in the MeshCAM Art forum, this is what I am actually doing. Perhaps the photo has the general appearance of a Lithophane, however it is almost an inch proud of the background area. The untouched MeshCAM Art output, was not very detailed at all. The detail was added by hand, using a Dremel tool. Greater detail is possible with MeshCAM Art, only by using a very small diameter tool (1/16" or even smaller) when generating the tool path. However, this ALWAYS results in a broken tool, because the amount of material remaining following the roughing cut, is simply too much for such a small cutter to handle. Which is why I would like to see a 3rd tool option-
Primary Rough (1/4" diameter preferred) Performs the heavy, hogging cuts to remove the bulk of the material
Secondary Rough (1/8" diameter preferred) Gets down into the nooks and crannies to remove more material
Finishing (1/16" diameter preferred) Only has to "polish" what little material remains, to achieve the greatest detail
It would be awesome, if this feature could be added to MeshCAM Art! (Perhaps along with the ability to "Ramp" between colors, another item for the wish book). Not complaining here, just items for future development, that I would like to see happen!
Have a blessed day!
-Michael
AdPrinter
 
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Re: 3 tool changes

Postby Randy » Sat Jan 30, 2016 5:45 pm

Ah, I see, Michael. You want to take the result from the first/coarse roughing and use that as the "stock" input for the second/fine roughing.

I can see how that would theoretically be done. I know that some $$$ CAM programs can do it. MeshCAM would need to model the result of the coarse roughing. LIke the existing simulation, but turning the result into an actual solid. Then save that solid and use it instead of a rectangular block as the stock for a new roughing and finishing toolpath generation. That would be pretty cool!

Of course, right now you can do a roughing-only with the first cutter and then do a roughing and finishing with the second and third cutters, but the second cutter would be doing a lot of air-roughing which is what I image you are trying to avoid.

Years ago when I realized I could rough with a ball-end cutter, that helped a lot with the 3D shapes I was cutting. The stair-stepping is mostly eliminated. But as you say, narrow recesses are still bridged over by the larger cutter. There is no getting around that.

And as always, I'll suggest that you send Rob an email at the MeshCAM support email address and point him to this thread. I don't know how he is doing the toolpath visualization in the current V6 Pro, but theoretically if he could save it as a solid he could use it as I said above. He would probably calculate a full roughing with the second tool and then filter out all the parts of the toolpath that don't intersect the saved solid/surface. I just thought that it doesn't need to be an actual solid, just a kind of anti-check surface. Only machine what is below it rather than keeping away from it.

An interesting concept! And in the meantime my suggestion of the "coarse" and "fine" finishing is the closest I've been able to come to what you want to do.

Randy
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
Randy
 
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Re: 3 tool changes

Postby AdPrinter » Sat Jan 30, 2016 10:44 pm

Thanks, Randy. I have considered the possibility of doing one tool path (using the 1/4" rough, and the 1/8" finishing tool), then regenerating the tool path, using the exact same file, using 1/8" as the rough, and 1/16" as the finishing tool. And maybe reducing the machining margin (material to remain) to something less than it's current setting of 0.01" But I haven't yet tried this approach, to see if it would yield a more detailed result. As you said, I imagine it would result in a lot of air-cutting in the roughing pass, however, I also imagine that it will probably break the 1/16" bit during the finishing pass. I guess that I am just going to have to bite the bullet, and see what happens!
Have a blessed day!
-Michael
AdPrinter
 
Posts: 56
Joined: Sun Oct 04, 2009 6:18 am


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