Hello Everyone,
I was wondering if there was a way to cut a groove on the side of an object. I would like to make sunglasses on my CNC and I feel like it should be possible to use a threading end mill to cut the groove for the lenses.
Does anyone know how to do this in any software?
Thanks!
Sam
Test.stl (3.7 MB)
In CC, I would draw a path that starts in the middle; moves to and around the rim; then moves back to the middle.
Another option for tooling is called a “lolipop” endmill. Harvey tools makes a bunch of different ones. (Warning, they are spendy and fragile)
Like DAH recommended, I’d think this can be done with a regular ol offset circle. Just make sure you’re checking the simulation and the tool is dropping in and coming out of the center as you expect.
Oooh, I wonder if the key toolpath in CC would work here? @WillAdams what do you think, can a lolipop be used for undercuts in CC (or CC Pro) 
Yes, a “lollipop” tool can be used, but no, it won’t preview accurately since it would need to be entered as a ball-nose.
I’ve actually been working on a library which can handle thread milling.
If @sfwclarke can post a link to the thread mill which they plan on using I should be able to work up code for this. (or, as @KevBarn14 would advise, one could just use Fusion 360 or some similar tool).
I believe Fusion 360 would allow you to define the entry and exit points for the tool. This would allow you to enter in the center, then create the undercut with a keyhole or similar endmill in a defined circular pattern, followed by a center retract. @wmoy would be the expert for such things.
Thank you everyone. I will admit that the above explanations are a bit above my head but I am so happy to hear that creating this side groove seems possible.
@DAH, would it be possible to create a groove that is not totally flat with this technique? I need this groove to curve slightly in the z axis in order to accommodate the lens. Apologies, I should have specified this.
@WillAdams, I haven’t chosen a specific threadmill yet. I just wanted to make sure it was possible. The groove would need to be 2mm in height, 1mm in depth and to follow a slight curve (to accommodate the curvature of the lens). So I guess I need to find a threadmill with at least a 1mm lip. I would appreciate any help with the code… or anything else.
@KevBarn14, thank you so much. I am utterly inexperienced with fusion360 but I have been meaning to learn it. I suspected that I would be able to accomplish this in F360. I have been able to achieve ALMOST everything I need with MeshCAM so I have been hesitant to dedicate the time to learning Fusion.
Sam
Cutting this open to see inside we see:
Creating a toolpath for this is simply a matter of:
If you’ll post a link to a tool which will make the cut as you wish we walk through this with you.
Hello again everyone. Thank you so so much for your help and apologies for the delay in responding. I thought it might be better for me to prepare the actual files I will use.
The STL files are the sunglasses frames that I want to mill and the lenses that I have used to boolean out the interior groove. The images are meant to illustrate that the interior groove is slightly curved.
@WillAdams: I found this 1/8in shank thread milling bit, seems like the M5 might work: Thread Milling Bit - 1/8″ Shank
Please let me know if there is anything I should clarify or any additional files I should upload. I am standing by!
Sam
Thick Frame With Lens Groove.stl (1.6 MB)
2mm Thick Lense with 1mm U Bevel.stl (3.5 MB)
My apologies, left this open on a computer I don’t frequently use…
Basically what should work is to import the STL, get an outline of the 3D model at the height of the groove, inset the perimeter of the groove by the radius of the tool, use Node Editing to cut the vector, then add a pair of lines which are >diameter in length which start at the begin/end nodes, then assign a No Offset Contour toolpath.
