Fusion 360 Post-processor

[JayMcClellan]

I recently started using AutoDesk Fusion 360 for 3D modeling and so far I'm really liking it. The learning curve is a lot steeper than something like VCarve but it can do much more and there are lots of tutorials out there (check out NYC CNC on YouTube). I especially like the built-in 3D CAM capability so I can go straight from my 3D model to generating toolpaths in the same application. AutoDesk licenses it free (as in actually FREE) for hobbyists and business making under $100K/year so it's very attractive for a hobbyist like me.

The only stumbling block was that there was no post-processor for the CNC Shark, so I wrote one. I didn't base it on one of the AutoDesk post files because mostly they're overcomplicated for what the shark can do (we don't need code for coolant, tool changes, radius compensation etc.). I offer this with no guaranty of course, so use at your own risk but so far it has worked well for me. Fair warning, I've only used it on a few simple projects so far and I've only been using millimeters so I haven't tried it using inches. To install, rename the file extension to .cps and then in the Fusion 360 CAM workspace, select Post Process. At the top it will show the Configuration Folder where post-processors are stored. Just copy the file there, and then it should show up in the drop-down Post Configuration list next time you open the dialog. The .tap file it generates can be loaded into the regular control panel and run.

Fusion 360 will run the post-processing with whatever toolpath(s) you have selected, and when using multiple toolpaths they should all use the same tool. I included code to check for this and to display a warning if the tools are of different basic types, diameters, tapers etc. but it doesn't require them to be exactly the same tool because they might differ by non-critical parameters such as cutting length, and even if it flags them as different you have the option to continue. Just pay attention to the comments in the .tap file that show the toolpaths and the tool types in use, to make sure it's what you expected. I also added comments in the .tap showing the overall part size and the total tool travel range in each axis, which I find a useful sanity check to help prevent tool crashes.

Note: The latest version of this post-processor file is now maintained on my web site at http://BrainRight.com/Projects/CNCController, where I have also published details of a new modular CNC controller that I made to run my Shark and other machines. The post-processor is available from a link in the Software section of that page, along with instructions for using it in Fusion 360.

[Kayvon]

The learning curve is a lot steeper than something like VCarve but it can do much more and there are lots of tutorials out there (check out NYC CNC on YouTube).

Can you recommend a tutorial to start with? I'm curious about using it over VCarve, but I don't want to invest several hours before having an idea of what I could do.

[JayMcClellan]

Here's a Fusion 360 CAD+CAM introduction video. It's titled a "tutorial" but he goes rather fast through some steps so it seems to me more like an introduction to give you a flavor of what it can do, not really a step-by-step tutorial. The first and longest part of it covers the CAD drawing functionality, and again it's more of a whirlwind tour than a training course so don't expect every step to be fully explained but you can see what drawing in Fusion is like. The workflow of going from 2D "sketches" to 3D geometry took some getting used to, but I'm really warming up to it. Then there's a somewhat outdated (and to me, boring) section in the middle where he talks about licensing etc. so you could skip that part if you like, and then he goes back to the software and spends a few minutes on the CAM functionality and shows how to generate a simple toolpath.

https://www.youtube.com/watch?v=o-GBpUZ3piY

This is just one of the first intro videos that I happened to find, and if you search for "Fusion 360" on YouTube you'll find lots of others. It's really a very powerful program, with a corresponding learning curve. But after a few hours I was able to draw a moderately complex part, generate toolpaths, and then machine it successfully on my Shark. It would have taken me less time in VCarve because I'm more familiar with it, but now that I'm learning my way around Fusion I don't expect I'll go back to VCarve. One of my interests is to model guitar necks in CAD and then carve them on the Shark, and what makes Fusion especially attractive is that it's a parametric 3D CAD program. That means I can dimension some of my geometry using symbolic parameters instead of fixed numbers, and when I enter new parameters (e.g. a different scale length or taper for the neck) it will automatically adjust all the 3D geometry and generate new toolpaths. So basically once I have the model working right, I can just enter all my desired neck dimensions in the parameter page and have toolpaths for it in minutes. That's just one example but it's the kind of capability you get in exchange for climbing the learning curve. If you're doing relatively simple things then you might find VCarve sufficient for your needs and Fusion might not be worth the time to learn, but if there's something you wish VCarve could do then there's a good chance Fusion can.

[bill z]

Jay,

Thanks a bunch.

I, also, tried a couple of other CAD CAMs only to find out that they did not output any G-Code that the shark could use. Yes, frustrating.

I'd like to try your TXT file.

When do you expect to have an 'Inch' version ready? Most all I do is in inches.

[JayMcClellan]

Bill, it should already work in inches or mm. I checked the G-code output in inches and it looks okay but I didn't actually try cutting parts with it. Try it and see if it works for you but just be cautious and cut some air first. Let me know if you run into any problems with it.

[bill z]

Jay,

Please. The really new guy to Fusion is needing some more help putting this .cps file where it should go.

Probably at the wrong place but I can get Fusion 360 CAM to open, select CAM. Here is where guessing comes in because it is not intuitive to someone never being in the software. I can get to a pop up on the right that has a tab saying Post Procdess but no folder is indicated.

Under Setup, just right of CAM, I can open a pattern and the pop up on the right says folder but that folder does not exist anywhere.

To test this, I'll need more details

[JayMcClellan]

Bill, I'm pretty new to Fusion too so I don't know if there's a simpler way to do this, but here's what worked for me. After you select the CAM workspace, one of the menu sections at the top says "ACTIONS". Under that there's a "Post Process" action, which may also show up as a button with "G1 G2" on it. Click on that to open the Post Process dialog:

The part I circled in red contains the path where Fusion looks for post-processor files. In my case the path happens to be "C:\Users\McClellan\AppData\Local\Autodesk\webdeploy\production\84f1b51e7d7e35aa10511b736710ea444a791fd0\Applications\CAM360\Data\Posts". You can right-click in that text box and select "Select All", then right-click again and select "Copy" to copy the path to the clipboard, then paste it into a File Explorer window to jump to that folder (here I assume you're using Windows, because Mac would be a little different). That folder is where you need to copy the post-processor file, and change its extension to .cps (I just had to add .txt in order to upload it to this forum). You might need to close and re-open the Post Process window in Fusion after that, but once Fusion sees the file then it should appear in the drop-down list as I circled in blue above.

The Property/Value settings under Program Settings in the dialog should be left as-is, but you can change the settings on the left if you want. Then just press the Post button and enter a path and filename to save the.tap output file. If the "Open NC file in editor" checkbox is checked in the lower-left, then it will open the .tap file in an editor so you can see the result.

[bill z]

Jay,

Since I didn't have Fusion, I downloaded the latest. Following your latest instructions, I went to the folder indicated and there was already a file named nwa shark.cps. I opened it and the file I downloaded from here and they both look to be identical. I'm not a programmer in that code but all of the commas, brackets, values and names were in identical places.

I mostly use my machine off line, Just don't want to worry with viruses. Not connecting is the best virus protection. It seems Fusion has some issues when not connected. It can do some things but really wants to know what you are doing. Big Brother sort of thing, I'm guessing.

It will take me a little time to create a test cut unless I can find a tutorial that is more basic than what I'm finding. Yes, there are a bunch but most assume you know the special shift, control and other shortcuts.

I'll be getting back to you.

[JayMcClellan]

I just uploaded a new version 1.1 of the post-processor that handles the safe Z level using the "Clearance Height" specified in the toolpath Heights tab, instead of using the max Z height in the toolpath moves. It also fixes a problem with comments containing parentheses, by replacing them with [ ].

[bill z]

Jay,

I have not forgotten about you and trying out your post processor.

It is like this; when you have an old favorite tool that you feel comfortable with and a new more complicated one, when trying to use the new one, after a while you are still not making progress, you go back to what works. Sort of like when my grand kids are learning to eat with a fork. They go back to their fingers to get the job done.

However, I'm making progress and will continue to work at it.

I do see that there is more opportunities using Fusion360. It has outputs for 3D printing and most any X, Y, Z device.

There is one thing that aggravates me some. Fusion360 requires me to get back on the Internet so they can sample my files and share them. It will not allow me to work without it.

In my opinion, the best virus protection is isolationism. Just my opinion.