Tool recommendations for 3d wave surface

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baniels
Posts: 128
Joined: Tue Sep 04, 2012 4:14 pm

Tool recommendations for 3d wave surface

Post by baniels »

Howdy folks,

I don't do much with 3D machining. I am working on a project now that has somewhat large panels with a 3D wave/ripple pattern on the surface.

I am wondering what you guys recommend for endmills for this project, for roughing and finishing. I don't need an ultra smooth surface, as I'll be using a paint that goes on with a bit of texture.

At its deepest, it is 1/2 below the surface of the 3/4 MDF. The side panels are 27.75x48.75 inches.

Image

I have a 50x102 KRMX-02, with an Hitachi M12VC, and Precise Bits UP collets for up to a 1/2" shank.

Should I use a large ballnose for this? Tapered ballnose? How big? I want to limit the machine time as much as possible.

Here you can download a zip file with an STL for one of the side panels: http://www.baniels.com/wp-content/uploa ... 2/wave.zip
baysale976
Posts: 494
Joined: Mon Dec 31, 2012 11:07 am

Re: Tool recommendations for 3d wave surface

Post by baysale976 »

Perhaps unintended, but the sharp edge where the 'wave' turns into 'flat surface' will be a mild challenge.

Other than that, cutting this should be no problem. Use at least a 1/4" ball bit, maybe larger to save time. Those waves look large enough to rough with a flat end bit, which may remove material faster. Use a small (75% or more) overlap for roughing, and reduce it to maybe 10-20% for final. Play with it to see what you get, eventually you'll come to a good value with a little experimentation.

One thing about 3D is that most programs don't cut the contour like you would, following the circular pattern, instead they cut at 90 or 45 degrees in a raster pattern. So there are raster lines visible unless your overlap is around 10-20%.
baniels
Posts: 128
Joined: Tue Sep 04, 2012 4:14 pm

Re: Tool recommendations for 3d wave surface

Post by baniels »

Thanks, baysale.

I think I'll probably build in a chamfer where the flat edge meets the wave, and make it equal or just over the radius of whatever finish tool I use.

I don't mind the raster lines too much as long as they are small enough that I can sand them reasonably smooth.
baysale976
Posts: 494
Joined: Mon Dec 31, 2012 11:07 am

Re: Tool recommendations for 3d wave surface

Post by baysale976 »

Depends on the overlap. 15% overlap with a 1/4" round nose might not even need sanding.

Honestly, I'd try one using a 1/2" straight bit with no overlap for roughing and 1/4" with 15% overlap for finish. Try to remove most of the material in roughing so the finish pass can run at high speed.
In Mach3, simulate several different bit configurations to check the run times. I do that all the time to optimize a job I'll be running often, or that's particularly long.

If you don't plan on making these in different sizes, you might consider programming most of the finish cutting in raw G-Code, so the tool follows the circular path of the waves and not a raster. Do you understand what I mean? It is not difficult, only tedious.
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