Week 3
Making a circuit board
Assignment:
1) Print and cut out a circuit board. Solder on the parts
The first step was to open up a file we were given in the Mods program on the computer hooked up to the printing machine, a Roland MDX20. We prepared a copper plate laid flat with tape, on top of a sacrificial layer, on the printing area. Then, we opened our file. We calibrated the z-axis, had the Mods pogram calculate the cutting path. The cutting path must be re-calculated every time you change the cutting blade or adjust the location of the copper plate or the cutting origin.
A friend and I decided to print a bunch of boards on the same copper plate for efficiency. Unfortunately, we forgot to properly record the origin of all the initial cutting positions for each board. This resulted in us cutting through one board.
Oops.
This one looks good.
After cutting shallow cuts for the electrical connections (the "trace" path), we made another pass to cut the boards completely separate from the copper sheet. This involved making deeper cuts, actually three consecutive cuts at increasing depths, with a thicker blade (1/32 inch vs. 1/64 inch for the traces). We changed the needle, re-zeroed, re-set the original and re-calculated the cutting path, then cut out our boards.
Now that our board is ready, it's time to solder on parts according to the wiring diagram we were given. To keep all the tiny components organized, I create a mis-en-place setup:
These parts are very small and the connections we need to make are even smaller, so we use fine tweezers to place the parts and solder them in place under a microscope.
This is my first time soldering so the quality varies considerably. Here you can see two very differently shaped joints that resulted. Apologies for the blurriness, this photo was taken through the microscope to enlarge the features:
In addition to overall shape, the mark of a good solder is that it should be "shiny and smooth." Here's how the finished circuit board looks with all the components in (hopefully the correct) place:
In future weeks, we'll learn to design and program our own boards. I'll keep the soldering iron hot till then.