Setting up some insets and chamfers for CNC. New to Fusion 360 and CNC.

[kevinEM1]

Hello All,

I'm very new to CNC and Fusion 360. I mainly 3d print on my Snapmaker Artisan, but I've gotten it into my head that i want to CNC a dicebox. I've set up a model and made two components. A lid and a box. I have some 2D contours setup for the body and pockets for the magnets and dice slots. But I'm at a loss on how to set up paths for 3 parts of the box.

My model:

Model

1. Unsure how to setup a path for this edge? I got one setup but it 'hops' over the inset

2nd edge

2. The inset I can't seem to figure out any path. I suspect I need to use a 3d slope path.

Edge

3. I tried using a 2d chamfer but i'm not getting a good result with the bit offset

Chamfer

My current paths look like this:

paths

[CNC_Lee]

@kevinEM1 

1 - can be achieved with a 2D contour toolpath chained to the profile geometry of the edge.
2 - can be achieved with a 2D contour or trace toolpath using a ball endmill and driving the tool with some geometry to define the centerline of the slot or "inset".
3 - can also be achieved with a 2D contour using a chamfer mill or spot drill with the chamfer parameters defined under the Passes Tab.

[kevinEM1]

Hi @CNC_Lee,

Thank you for your time it's already helped quite a bit (pun intended).

1. Im not sure what you mean with chaining to the profile geometry. But selecting the upward face of the lower edge i got this:

2. I guessing I need a longer bit for the inset.

3. For the chamfer i'm trying to select the 2d Chamfer option, setting width: 0, clearance: 0, tip offset to 0.1mm. But i'm getting empty path warnings if i select the contour.

[CNC_Lee]

@kevinEM1 
 
Potentially! It is hard to tell exactly what you have going on without reviewing the file.

[kevinEM1]

@CNC_Lee Added some more context to my above post. Trying to find out how to attach my file!

[CNC_Lee]

@kevinEM1 

You can attach files under the chat box as shown:

[kevinEM1]

I got that but i mean where and which file 😛  Should I just export a .f3d?

[CNC_Lee]

@kevinEM1 

Correct! Export the .f3d file and attach it.

[kevinEM1]

@CNC_Lee  Attached!

[seth.madore]

Give this file a look. I've added a few toolpaths; 3D Contour to rough the inset, 2D Contour to machine the chamfers (you're chamfer tool was defined as 10 degrees, you've modeled 45's).

To open the file: Click on "File" > Open > Open from me computer > Select file

 

[kevinEM1]

@seth.madore many thanks! Very helpful, learned a lot about the different contours already. I do have some more questions about the file if you don't mind.

1. Looking at the 2D adaptive contour, I see you selected the inner chain and then used the stock contour toggle to define a 2nd border of sorts. Is that correct?
2. The 2nd outside box contour, is that to smooth out the existing edge?
3. Hopefully, I understand the next bit correctly, you used a 3D contour to first define the bottom size and the upper size and then use a 2nd 3D contour to slope between those two.

Much appreciated, learning CNC and Fusion is amazingly good fun.

[seth.madore · Accepted solution]

1) Yes

2) The Adaptive had "Stock to Leave", so we need a toolpath to finish those surfaces

3) Yes, the 1st toolpath roughs it out, the second one finishes. Of course, if this is a soft material and the machine is stout enough, you could likely just use the second toolpath to act as both rough and finish

[kevinEM1]

Hi @seth.madore,

Cheers for the support thus far. Set me on the right path. Wanted to share some lessons learned.

1. I gotta tighten those clamps!
2. Somehow, my machine (Snapmaker Artisan) ignored the set spindle speed and went for the full 18000 rpm, which is why i think there is a lot of fraying. Is this where I should add stepping?
3. My machine also ignored the 'Force tool change' commands and simply stopped altogether.
4. I moddeled my box with a 17mm height, but i forgot to account for a 0.7mm in stock. How best to fix this? Do i shave it off or can I set the setup stock to have 0.7mm at the bottom?

Coincidentally, when i turned it on i started smelling this really strong burning smell. Thought it was my project, turns out there was a fire on the 1st floor. 

Cheers!

[seth.madore]

1) Yep, folks often underestimate the cutting forces at play. It's something that's understood better over time (the same can be said for over-tightening)

2) Does your machine support specific RPM control, or is it manually controlled with a rheostat?

3) Does your machine have a tool changer, or does that need to happen manually? If it's manual, I would expect the machine to just stop and wait for you to command a "cycle start"

4) Are you saying that your part is thicker than it should be?

[kevinEM1]

@seth.madore Hi Seth, seems I need to manually set the speed on the machine. I saw mention somewhere that I need t use a different post processor to make it accept the speed and stop command so i think that's the next thing I will look at.

Regarding the part, it's thicker by about 0.7mm. If in Fusion i orient it in the setup box towards the top with extra stock at the bottom. it should be fine, right?

[kevinEM1]

@seth.madore I used a different post processor for the Snapmaker Artisan that was maintained by someone with the same challenges. Speed was still ignored but I could use my machine to set it to 12000 rpm instead of 18000 rpm. I've created different cnc files for the insets so I don't have to use the stop action. Sadly this was the result:

at 94% the bit went off the path somehow and my machine stopped and threw an error. Maybe it's the wood?

After a quick Google i see that I'm using a hardwood called Meranti.