This past June for the Forge Developer Conference I worked with some of the great folks at opendesk and ShopBot to put together a working demonstration using their furniture designs, machine tools, and Fusion 360.
opendesk has a large catalog of furniture designs that are made locally on-demand from sheet stock. You should check out their website because it’s an interesting concept. ShopBot has a selection of CNC routers in all sizes from large 12 by 5 foot monsters down to the portable Handibot. We decided to use the Johann Stool design from opendesk and allow attendees at the conference to design custom engravings for the top of the stool that would be cut at the conference using a ShopBot tool.
I got involved to try and create a simple interface to allow non Fusion 360 users to easily create a design and send it to the router. This consisted of two parts. First I created a series of Fusion 360 custom commands that draw various designs as a sketch. The picture below shows the new panel that the add-in creates in Fusion and its commands. There are several different patterns that the commands allow you to create. The one shown below creates a rectangular mesh with the grid positions randomized. There’s also a command that creates several polygons to create a flower pattern, one that creates circles in a random pattern, one that rectangles arranges randomly, and finally one that draws sin curves.
The main thing to remember with all of these specialized commands is that they’re just automating the creation of sketch geometry. Below is the result of using the custom sketch commands and a bit of manual editing on the resulting sketches to create a new design.
The last custom command provided by the add-in sends the design to the CNC router. To make the entire process easier, it doesn’t use the NC capabilities of Fusion 360 but with a single button click it directly creates the g-code data from the sketch geometry and sends it to the CNC router. The command gets the geometry information from the sketch and essentially treats the sketch geometry as the tool path to create a g-code file that will drive the cutter along the sketch geometry. Splines and circles are stroked into small lines and text is also converted into lines so the g-code consists entirely of point-to-point directions. Below is an example of one of the stool seats that contains some text. To reduce the time at the conference to create a stool the stools were already mostly cut out in panels of birch plywood and then only the custom pattern on top needed to be machined.
Here’s Bill from ShopBot at the booth cutting a stool top. Bill also reported on the experience in his blog.
Besides doing the stools, ShopBot also brought a couple of the portable Handibot CNC routers and we used the same process to machine small badges that people could design in the same way. If you haven’t seen the Handibot before you should check out the website and look at some videos on YouTube to see what people are doing with it.
The whole process of getting ready for the Forge conference was a lot of fun and very educational for me. CNC isn’t new to me but I hadn’t every directly written g-code before. The entire Fusion stool add-in is currently available on github. This could easily be done with Inventor too but so far I’ve only needed it for some Fusion 360 events.
After the Forge conference, a couple of guys from Autodesk (Philippe and Lucas) wanted to do something interesting with a Handibot at another event. They liked what we had done at the Forge conference and had the great idea of cutting chocolate. Philippe is a much more colorful writer than me and has written a report about their adventure with chocolate.