The club has been given the loan or donation of a Mill that Jeff VK2WSR has used to cut the tracks and holes onto circuit board. Several pieces of software are used to draw and convert a circuit diagram into a format that can be used to drive the Mill.
Jeff’s notes are below:
Below is a link to the site that I used to learn how to use the mill for PCB’s. All is still the same but the last software it mentions (Maker)? is no longer available, so I now use Easel instead.
https://www.instructables.com/PCB-designing-and-isolationmilling-only-using-free/
Also, attached is a brief rundown as to what software I use and what each does. While it looks like a lot of work, there are only a few steps in most before moving on to the next. The longest time is spent in Fritzing and Easel. I recommend looking at some short YouTube videos on each program. Below is a somewhat more detailed explanation for how Jeff uses the mill to prepare circuit boards for populating with components.
Fritzing
This is FREE software is used to design the PCB layout. It produces footprints for the components, allows track manipulation and can export as a .svg file needed by both Inkscape and Easel software. I would use this at home before going near the mill. I find this very intuitive. It may cost 8euro now but that is a one-off payment for the software.1
Inkscape
This is FREE software used to create the PCB track images as “Grouped” objects. This is done so the mill will not cut across other tracks but will trace around each grouped object. This is in preparation for the Easel software to produce the mill pathways. This software would also be used at home before needing the mill.
Download Inkscape – Free – latest version
Easel
This software is not free, but I believe there is a free version. There is also a 1 month free trial period. I use the Easel Pro version $24/month2 but can be cancelled any time. This software prepares the G-code that will be used by the mill to cut the board. After manipulation and setting up tooling parameters (such as drill holes and depth of cut), it writes the movements of the tool into code understood by the mill (G-code). Effectively, leave the “printed” circuit and mill away the background to a depth of 0.1mm. While this can be used away from the mill, I think one copy at the mill would be cost effective. Once the G-codes are written, they can be saved and Easel need not be used again unless changes are needed to the G-code.3
Easel ® | CNC Software | Official Site
Candle
Finally we reach the FREE software that runs the mill directly. This code takes the G-code and instructs the steps for the stepper motors so as the mill bit can cut out the image of the tracks and pads needed for the PCB.
Candle download | SourceForge.net
I am happy to run some Zoom meetings to demonstrate how these products are used to develop PCBs. I am self taught regarding using this stuff so it can’t be too hard. Also, I’m sure there is other software available, but these are the ones I know. Download them and have a play.
1 Not too bad a price to have this relatively powerful PCB design software. Single payment that helps with future development for free updates.
2 Surely SARC could cover this cost, cheaper per month for longer periods.
3 You can change the G-code in Notepad if you’re game. BE CAREFUL.
Fritzing screen showing a circuit being prepared
Above is a screenshot from Duncan of the Fritzing software that is the first step in the process of sending a circuit to the Mill which cuts the tracks and holes to allow components to be fitted. The link to the Fritzing software (free) is here:
The photo above shows the circuit at left and the Fritzing program’s version beside it. You drag a component from the tools at the right and draw a line (conducting wire) between them. Component values can be added. That’s a bit of an oversimplifying description but there are numerous You-Tube videos out there explaining it. Our resident expert on the process is Jeff VK2WSR who has made use of the Fritzing software to carry out the first step in the preparation of PCB and other circuit boards for projects, very successfully too. The final bit of software converts the circuit into code that positions and drives the Mill to cut the holes and tracks. It’s fun to use the Fritzing software. We have had three Zoom sessions on Thursday at 2pm recently going over the software.
de Paul VK2AMT