Efficient toolpath for eyeglasses frame with custom stock

[Anonymous]

Hello,

I recently started using Fusion 360 and my first project is machining a pair of eyeglasses frames with nose pads.

The main frame is flat and the nose pads extrude straight up from the main frame.

The stock is a two-layer configuration, with the bottom layer used for the main frame and the top layer used for the nose pads. The bottom layer is the exact same thickness as the main frame while the top layer is thicker than the nose pads. (see attached Frame_and_Stock.png)

I tried a very simple example in Fusion 360 by creating the basic shape of the eyeglass frame by extruding an outline of the frame made with splines. Then in CAM, I was able to use 2D contour to get a good roughing pass to get me 90% of where I need to be (see attached 2D_contour_toolpath.png). The remaining 10% is machining the nose pads.

However, the challenge I face is when I try to import frame designed and exported as a mesh in .stl or .obj format from Rhino. First of all, I read that you can't perform 2D CAM operations on mesh, which means I can't perform the efficient 2D contour toolpath. Second, it seems like the 3D operations in Fusion are not smart enough to realize that it shouldn't waste time removing unnecessary stock (see 3D_adaptive_clearing_inefficient.png).

I tried other methods like converting mesh > quads using ReCap Pro, but fidelity of the frame after conversion is terrible (quads_mesh.png). I also tried to convert mesh to brep, but I still don't get a nice contour (brep_bad_2D_contour.png) like I did when I designed the frame in Fusion from the start. 

I'm really stuck on this part... it doesn't seem like such a difficult ask but I'm having a lot of trouble with it in Fusion. I tried the same .stl in MeshCAM and their automatic toolpath wizard did quite a good job with not removing unnecessary parts. But unfortunately, MeshCAM doesn't support custom-defined stock.

If anyone is able to give some guidance, I would really appreciate it! I'm also willing to pay you for your time if you can provide a detailed walkthrough for my problem, just give me a PM.

Fusion Archive file is also attached.

Thanks,

Alan

[martin.dunschen]

Hi @Anonymous

You did not include any toolpath in your Fusion Archive, so I don't know the tools you were intending to use. From the images you included I conclude that you have not defined what the input stock shape should be: The strategy assumes that your input stock is a rectangular block that includes your model. If that is not the case, you have various options how to define the input stock, for example take a look at the geometry tab for the machining strategy where you can select various options. You can also set the initial stock in the Setup. For example you could model the stock shape that you intend to use as a solid and select it in the setup.

Martin

[Anonymous]

Thanks for your reply, Martin.

For the toolpaths, I tried a few but ended up deleting them. I use just a 1/8" flat end mill for roughing and then a 1/8" ball nose for finishing. You can see some of the toolpaths I generated from my images 2D_contour_toolpath.png, 3D_adaptive_clearing_inefficient.png.

Also, I actually did use the method you described and use a solid that I modelled as my stock, rather than a rectangular block. You can see in 2D_contour_toolpath.png that my stock has a large bottom layer and the top layer are two smaller rectangular blocks laid on top.

Hope that clears up my case.

Alan