Trouble getting a 2D tool to cut a slope on an outside surface

[paramax55]

I am trying to cam up this part and the next step that I want to do is rough slope on the outside of this part. I can't get F360 (my fault I'm sure) to recognize the slope for me to select it. The surface is what I have so elegantly highlighted in red.

https://a360.co/3xSz5vI

[engineguy]

@paramax55 

You either do not have permission to set your file to be downloaded or you forgot 🙂 🙂

Try the 3D ADaptive for Roughing and then 3D Contour toolpath for a Finish, all I have without seeing the part 🙂 🙂

Easiest way to get a Fusion f3d file uploaded to the Forum is to go to :_

File > Export > Select f3d format > Save it to a location on your computer > Then attach to your reply.

If the f3d format does not show as an option then you likely have links in you file to outside sources so you would need to break any links 🙂

[paramax55]

Let's see if this worked...

[paramax55]

Specifically, I can't select the face, nor can I select the edges to be a boundary. It keeps trying to select the stuff on the other side of the part (through the part like x-ray vision).

[engineguy · Accepted solution]

@paramax55 

Try using the "Avoid/Touch Surfaces" option and you will be able to select the face to machine, see images below and attached file. Might help you but to get anything like a decent finish you will need to do very small stepdowns with a very small Ball Nose 🙂 🙂

Hope it maybe points you in a direction that does the job, good luck, looks like a lot of machine time for that part 🙂 🙂 🙂

SELECTING FACES

SIMULATION

[paramax55]

Aha! That is what I needed! Thank you!

There is so much cryptic stuff in Fusion 360. I used to code cam for a 4-spindle router 30 years ago - and that router was made in the '70's. I'm trying to get back into modern stuff, but it is a whole different game. It's frustrating to get so close to something and have one little mouse click hold you back. I have no problem getting my answers out of a book, except that the answer is one sentence in a book that is 3 feet thick.

[engineguy]

@paramax55 

Yes, agreed, there is much to learn and a lot of it is not immediately intuitive, hence the huge value of the Community, there will always be someone including Autodesk employees that can help you so keep asking questions as often as you like 🙂 🙂 🙂

[paramax55]

I found an issue with that solution... The tool will start to cut at the top of the slope. As it goes down the slope, it will move out, following the contour of the slope. That is all fine and well, except that it is also cutting a pocket. The first pass will cut a slot the width of the tool (for the sake of argument). On the second pass, the slot will be the width of the tool minus the slope of the slot... and so on, getting narrower and narrower - except that the tool is shoving itself to the outside on each pass. Now. provided that the cutting depth of the tool is deep enough, and the steps are shallow enough, the tool will survive, but it doesn't seem a very elegant solution.

Is there a way to specify that the tool cut the full width of the pocket on each pass?

[engineguy]

@paramax55 

Yes, you can either use "Patches" under the "Surfaces" tab to create a full face, fill the pocket with a solid or create a sketch for the Boundary, in the image below I used a simple block to fill the gap and did the Pocket in a second setup, I just duplicated the model before filling the gap and then used that body in the second Setup so it could have a different toolpath from the original 2D Pocket which was not the correct toolpath for that gap 🙂

[paramax55]

I don't think I worded my question correctly, but I think the answer is the same. My screenshot looks different than yours in the stock that is left over. Fusion is not clearing enough space in the previous cuts to make room for the tool in the following cuts. You can see in my screenshot that the tool would have to be a submarine to do what Fusion is expecting it to do.

But like I mentioned, I think the answer is the same... There is no "button" to click. I need to use the original part to make some fake geometry to machine away before I start working on the slope?

[paramax55]

@engineguy 

Am I correct about needing fake geometry to cut?

[engineguy]

@paramax55 

To answer your question, no, you don`t have to make extra bits of geometry, up to you what toolpaths you use and more importantly the order that you machine things, I can only show suggestions that I think might make it easier for you and may or may not help you, just ideas 🙂 🙂 🙂

See image below for some rough ideas and attached file, run the simulation first and then go look at the toolpaths and settings 🙂

[paramax55]

@engineguy 

I see where our differences come in and it starts with your very first toolpath. I am including a picture of my setup and hopefully you can see my delima. I can't cut the outline of my part as my first operation because I need the stock to hold the part. My plan is to cut all of the bottom grooves and slopes that I can't get to from the top side first, then flip the part over and cut the curves, then finally cut the part out of the stock.

Yes, I have had some dragging boo-boos 🙂

 

[engineguy]

@paramax55 

One of the reasons it is being so difficult is that you don`t have the Model correctly orientated, a tip, if you are going to machine something on a 3 Axis machine like yours then you should set it up with the Z axis pointing upwards towards the spindle, you have the Y axis "up" and the Model turned around somehow, just make life more difficult than it needs to be !!!

I have only given you some ideas for toolpathing, I am not here to do your "workflow" for you, the best I can do with the time that I have available is try and point you in the direction you need to go 🙂 🙂

No, you don`t need to cut the full model out but you need to clear material away in order to get to each Operation without plunging small tools deep into the stock, see the image below for a way of clearing just some stock away, I made the stock 4x5.0.5, I have no idea what size stock you actually have so just a representation along with the fixture blocks 🙂 I just did a small sketch to use as the machining boundary, you can make one any size/shape you like, the one I did is just to show what can be done !!

To do something similar you would need to very carefully go through all the settings for every operation and set all the feeds/speeds/stepovers/stepdowns/leads in/out etc, etc , etc, maybe change to different operations

[paramax55]

@engineguy 

Thank you! I will take a look at the file when I get back, but that looks like the (almost) exact toolpath that I am looking for.

I say "almost" because my setup on my machine is just like your screenshot - if you rotate the stock 90 deg counterclockwise. And my stock is the same size as in the cad (I machined it to size on the manual first). My origin is in the bottom left corner (Z0 at top of stock), the x axis is positive to the right, the y axis is positive away from me, and the z axis is positive toward the sky.

I understand that you can't do my wotkflow for me - nor would I want you to. And I appreciate your time. What I needed was to learn about "touch face" and then learn how to contain a roughing operation when I don't have geometry to select. These are skills I will use in the next 100 parts that I design and the large cnc conversion that I have planned. I have probably watched 30 videos on cam so far and it seems that everyone is making the same five videos over and over. Nobody that I have found addresses these issues. If you can tell me where to get some more advanced training, I'm all eyes and ears.

I have come a long way in a short period of time - from not knowing these machines existed to building one, then adding my own electronics, hooking up a raspberry pi with a rasbian desktop, controlling it with a combination of octoprint and bCNC, learning a bunch of the cam workflow, and performing several successful machining operations already. I do have a full ability to learn if pointed in the right direction.

[paramax55]

@engineguy 

Thank you for this solution. This is more than what I need, I just don't know exactly how you did it. Specifically, your first tool path is what I need to know how to do. I can't figure out how you selected the triangular boundary. Nothing that I try select in the geometry gives me a triangle like that. The rest looks self explanatory.

[paramax55]

@engineguy 

Sketch geometry! That's what I needed to know! That's what I was referring to back in post #10, but I didn't know how to word it. Thanks!

[engineguy]

@paramax55 

I did explain that part in my post, I created a small Sketch in the Design Mode and then back in the Manufacture Mode I was able to select the outline of the Sketch as the Boundary, as I said, you can make such a sketch any size/shape you like, make it smaller/larger/rectangle, whatever you want to suit the material you wish to remove.