Week 4's Goals:

• Group Assignment
• Characterize the design rules for your in house PCB production process
• send a PCB out to a board house
• Individual Assignment
• make and test a microcontroller development board
• Tools Used
• Adobe Illustrator
• Bantam Tools PCB Milling Machine
• Bantam Tools - Software
• Soldering Iron
• SEEED XIAO

Well I thought this would be easy...

Milling a Circuit

This week we were tasked with milling a circuit. Last week's class held a lot of warnings from Neil that had to do with the work being done. Millings bits would break, specifications are precise, etc. And honestly all of the above happened and more.

Keeping it simple I decided to work on the same circuit that was proposed to us:

The QuenTorres Microcontroller Development Board

The files were given to us so we decided to go for a run. In the lab at the Moonlighter we had a Bantam Tools PCB milling machine. Actually a discontinued model but I will say when it gets working it does the job well. It mills beautifully and autoprobes so you dont have to worry about offsets (mostly) among other things.

The idea was to use the png images to the Bantam Tools cutter and then cut the board, easy peasy. But we ran into our first issue right there, the Bantam tools software does not take pngs, it takes svg files. This made us convert the images to svg's in Illustrator. There may be easier programs but that is the one we knew.

The process to do this conversion is pretty simple.

• Open the png in Illustrator
• Go to Window>Image Trace
• Click on the advanced drop down and click Ignore white
• Click Expand
• This will make the image into a vector ignoring the white for the Bantam Tools Software

If you do not follow this process while using the tool you will get an image like below. Milling out EVERYTHING

If you do it right you will get an image like this:

Yay the traces are there and we can send it to the mill! Which we did and ended up with a pretty good product, except there was one issue, we were missing the holes.

We followed the same process as before to alter the holes image but there was an issue, it created a file created holes, but not in the right position. So we had to play with tools inside of the Bantam software to move it to where it went as best as we could. As you can see, this did not work well

This led to a lot of trial and error eventually having us to try to open the Gerber file. Which worked beautifully.

The Difficulties of Milling

From here we thought it would be a done deal. Click mill, change tools, let it work. We were very wrong. Unfortunately we ended up breaking 5 mill tools and cutting a bit into our board due to characterizing our machine a bit too late.

After all the tries you see above we finally got a good product and started milling the ones we needed for the lab

We cleaned the chip with soap and water and got to soldering

Big Hands Small Solder

I was experienced in soldering but this was the first time I used surface mount parts by hand. And I will say I had the hardest time getting them on. And spoiler, I will be remaking this board soon because I do not like how it turned out.

The biggest issue was that I melted one of the leads off in this section.

But luckily the circuit works!