Tuesday, January 19, 2016

Solidworks to gcode for ShapeOko 2 using Autodesk Fusion 360 CAM

I've been searching for a while to find the best (and cheap) way to go from Solidworks 3D CAD files to gcode to run my ShapeOko2. After reading through the forums and trying a couple different options, the software the worked the best for me was Autodesk Fusion 360's built-in CAM package. Fusion 360 is a full featured 3D CAD package- and the best part is that it is free to students / hobbyists. I think that's a great strategy to widen their user base, and it's beyond me why Solidworks doesn't adopt a similar model.

The first parts I wanted to cut were some 1/4" thick 6061 aluminum sections for a home-built adapter to put a Trail-A-Bike on my Yakima roof rack.

I could have modeled the parts in Fusion 360, but since I'm more familiar with Solidwork's interface, I created the .prt files in Solidworks then imported them into Fusion 360. Another option for model creation is Onshape's excellent CAD package- which is very similar to Solidworks, and also free for Home users.

So, the software toolchain I used was:

  1. Model in Solidworks, save .prt file
  2. Import into Fusion 360
  3. Use Fusion 360's CAM module to create the toolpaths
  4. export Gcode
  5. use gcode sender to send to Shapeoko2

Creating a toolpath from a .prt file is much more involved than simply 3D printing a part- with a lot more pitfalls. It took me quite a few tries to get the process to work property. I cut out a complete set of parts from 1/4" plywood before I even tried cutting aluminum- it's a lot cheaper to scrap than aluminum!

I found a good tutorial video on Fusion 360's CAM:

Initially I had some issues with Fusion 360's generic GRBL post processor (plug in to generate gcode optimized for the Shapeoko's software). After some searching I found and improved one to use:


Link to post-processor:

I did find a couple settings to tweak on the post-processor:
set "retractheight" to 5mm
set output units to "mm" - definitely do not forget this, otherwise you'll have big problems.

Cutting aluminum with the Shapoko was also a trial and error process- lots of experimentation with feeds 'n' speeds and lubricant. I liked CRC True Tap coolant / lubricant I found on Amazon. WD-40 and 3-in-1 oil also seemed to work OK.

The final Trail-A-Bike rack adapter worked great- and kept the Trail-A-Bike safely secured during a 1,500 mile road trip.

I did learn some lessons about the Shapeoko2 cutting aluminum. I really want to do any modifications possible to stiffen the structure- stock it's pretty flexible to try and cut aluminum at anything but a very thin layer / stepdown.

Also, the plywood trial copy didn't exactly work- it was slightly thinner than 1/4", and was a little misleading about actual fit on the Trail-A-Bike. The plywood version fit exactly right, and the aluminum didn't. And, since I finished the aluminum version the night before the big road trip I didn't have time to re-design and re-cut all the parts- so I broke out the dremel and manually ground the parts down to make them fit. They were a bit ugly but still worked.

Cutting trial part from plywood
Completed trial part
Assembled Trial Rack Adapter

Assembled Trial Rack Adapter

Getting Aluminum cut set up

Cutting Aluminum
Completed Aluminum Part
Completed Trail-A-Bike to Yakima Rack Adapter: