Inkscape is a popular, free and easy to use vector graphics editor. It won’t give you the powerful part manipulation features of a CAD program – but it is a comfortable working environment for artists or designers that may be more used to Illustrator, Canvas, Xara or similar art packages. The current version of Inkscape (.92) comes with a plugin for generating Gcode, a popular language for running small CNC mills. The process for getting from artwork to code and then to the mill is not well documented and can be very confusing for a new user, so I’m going to explain the process step-by-step in the hope that others can find it useful.
Orientation points and the tool library.
In order for the Gcode plugin to generate code, it needs to know where to place the origin (zero X,Y) of your drawing and how deep you need to cut. These values are set using the orientation points. You can move these points to other areas of the document, but be careful not to accidentally group them or edit them when you think you have another part selected or they may stop working. You can delete them and re-generate them at any time if they become broken.
Next we need to tell Inkscape about your tools and how you want to cut with them.
Generating the code.
Check the Gcode
Level the Gcode
Autoleveller is a simple but invaluable piece of software that makes PCB or artwork engraving a reliable, repeatable process. It modifies your Gcode to include instructions for probing the surface of your work, recording the variations in height and applying those variations to your cutting job. If PCBs are your focus get this software or something similar without delay.
It was immediately obvious that painting over the top of re-shaped keys was just not going to be good enough. The existing keyboard I had been shown was functional but looked like a mess. These keyboards would probably see heavy use by students so I needed something very durable that also felt natural. It’s hard enough learning a new way of playing a keyed instrument without the distraction of paint coming off under your fingers.
I decided to re-cast the tops of the raised keys (previously the sharps and flats) in solid white resin. This increases the mass of the key a little, but that is not a drawback. The more expensive Korgs that use this keybed have weights installed to give them a better feel and even out the stronger spring response of the shorter keys. The extra weight of my solid tops is improving the keyboard!
The epoxy only takes 10 minutes to harden and has a pleasant glossy finish that matches the existing keys well.