This is a short little Instructable to explain how I design parts to be machined on my Shapeoko 2 CNC machine from Inventables.com. Everything that I do will be using free software or web based services, nothing fancy at all! The only official CAD training that I have is for printed circuit boards, PCBs so I am not a very good 3D modeler, so in this Instructable I will be using PCB design software to layout 2D designs, then using a CAM tool I will be able to create a 2.5D design that I can then cut on my Shapeoko 2.
Step 1: Software and Web Tools
There are four tools that I will be using to go from design to finished item.
1. Eagle PCB - for generating the design.
2. Inkscape - for editing and combining SVGs from Eagle.
3. MakerCam - for generating the tool paths and gcode from my SVGs from Inkscape.
4. ChiliPepper - for sending the gcode to my Shapeoko 2.
Step 2: Creating Your Design in EagleCAD
Now, I know that Eagle is not designed for creating 3D models but I am very familiar with the software and can use it much better than a traditional 3D modeling software. Since most of what I do on my Shapeoko 2 is really just cutting out 2D shapes in a 3D material, this workflow is really for 2.5D carving, not true 3D milling.
There is really nothing to this part, if you know how to use eagle, you generate your design on layer 20, the dimension layer. Once you have created your design and are satisfied, make sure that all layers are hidden except for the dimension layer. Then you simply run the pre-installed ULP 'eagle2svg-1_1'. I choose to do mine in monochrome but it will not make a difference if you only have one layer visible. That's it for this part!
Note: This is NOT a tutorial on using Eagle, just the tools within.
Step 3: Editing Your Design in Inkscape
Once you open Inkscape, you want to IMPORT the SVG that was created from the Eagle ULP. I have had issues with directly opening the SVG in Inkscape. Typically, all that I do in Inkscape is set the X and Y position to equal the diameter of the tool that I am going to use on the border. This way when I import into MakerCam, I don't have to move the part. Save this as a new SVG file and you're done!
Step 4: Import Your SVG Into MakerCam
Once you have created your new SVG in Inkscape, you can open it in MakerCAM. Before you open your file, in MakerCAM you need to change the setting for the resolution or px/inch. To do this in MakerCam, just go to 'Edit' -> 'Edit Preferences' and it is the first option. Change this to 90. Now you can open your SVG. You will see that your object is only in quadrant one, if you import the SVG that was created from Eagle, you would see it straddle the Y-axis. Create all of your required tool paths/cuts and export the gcode.
Note: This is not a MakerCAM tutorial, go here to learn more about using MakerCAM.
Step 5: Load Your Gcode Into ChiliPepper
The final step is just cutting out the design! I have been using the ChiliPepper service lately for sending gcode to my machine. I have my machine connected to a Raspberry Pi running a JSON server so that ChiliPepper can connect over my internet connection. In ChiliPepper, all you have to do is drag your gcode or .nc file into the web browser and push play after zeroing out your machine. Then in a few minutes you will have your part!
Note: Stay tuned, as I have plans to explain how I setup my Shapeoko 2 with a Raspberry Pi to work very nicely with ChiliPepper.
Step 6: Final Thoughts
Now I know that this is not a very detailed Instructable but I more aimed it a individuals who have experience with hobby CNC and the Shapeoko platform. I just wanted to share how I get things done not being a 3D designer or master CAD user. I hope that you have enjoyed this Instructable. Please comment with any questions or tips of your own that could help me to improve mine or others work flows!