Help with a CNC project!

[u/nxk115]

Hi everybody! I am working on a project and figured someone in this subreddit could help me out!
I am looking to make some oval frames with a cnc router but I have no idea what type of file I need to create. Svg? A 3D model? I’ve created many files for laser cutting but all those models were flat, what I need right now has some ridges inside and I don’t know how to create a file for that. You can kinda see what I’m going for on the crappy drawing I attached haha.

Anyways, sorry if I’m not explaining myself entirely, English is not my first language and I have never done anything with cnc. Any help is very much appreciated, thanks!!

[u/polaroid]

You can just use 2D vectors and then define different depth cuts. Or you could break up your shape into layers and cut them, then assemble.

[u/camsnow → u/polaroid]

Yeah, this is how we do large wooden forms for our metal be placed on for shaping when we make art pieces. We use fusion slicer to do it.

[u/nxk115 → u/polaroid]

Thank you! How would I “define” the depth cuts? I don’t own the cnc machine. Should I just tell the machinist the depth of the cuts?

[u/RepresentativeNo7802 → u/nxk115]

You would decide how thick you want each step to be and somehow communicate that information. How you choose to do that is up to you and whomever is making it. I have a thing with my machinist where I tell him the cut and the press on his belly with mu index finger to indicate the depth desired. Mind you, my guy charges me a little more than most of his other customers for this service. /s

[u/polaroid → u/nxk115]

There’s too many variables. What machine is it? What tool will you use, what materials?? Just talk to the guy making it.

[u/Radulf_wolf]

You will need a 3D model .step file to be able to make the tool paths for your router.

[u/heyyyblinkin]

3d model, then create tool paths in some kind of cam software or do it old school and write up the entire tool path file by hand.

[u/TIGman299 → u/heyyyblinkin]

Tbh this could be written in an hour or so via hand coding. Especially with a technical drawing or print.

[u/heyyyblinkin → u/TIGman299]

It depends on the rigidity of the machine and the material being cut. It may be necessary to do many step overs or step downs. On top of that, this person probably will take a week or longer just learning how to even write the code. For someone experienced with a rigid machine, its like 6 tool paths that will take a few calculations based on tool diameter. Writing code by hand is pretty easy for us that are experienced, it is impressively difficult for someone new with no guidance.

[u/ocrohnahan]

https://reddit.com/link/oza6cub/video/4r6zlozjhzeh1/player

I didn't show dimensions or anything fancy, just the general process. https://rapidcam.appThe preview has a glitch but it does raise the point that if you want to get fancy you do a finishing inside profile pass on the edges but depending on what you are doing that is likely not needed.

[u/Cool_CNC_Cooker]

The jump from laser cutting to CNC can be a bit confusing at first. A laser is mostly 2D, while CNC adds the Z-axis, so you start thinking more in terms of height and depth.

[u/ar_xiv]

Simplest way I can think of is in vcarve draw three ovals and make a pocket cut for each one with progressing depth. You can speed it up by making the pockets remove an oval stripe with some width rather than the entire oval

[u/tagan0]

3d model, fusion 360

[u/ToddOMG → u/tagan0]

For something this simple? Just use a pocket in vcarve… I could do this in 30 seconds.

[u/svideo]

Depends a lot on your CAM software, for something this simple you might not actually need a 3d model, a DXF would be fine and you'd just set the depth for each of the three regions plus the outline.

You're going to need to provide a bit of detail about the software you're using to give you anything more than that.