<. <br>
####Objective <br>
To mill a pre-designed PCB and stuff it with components to make a microcontroller.
####Metrics <br>
* Milling machine: Roland MonoFab SRM-20
<br><img src="./3d-milling-machine-monofab-srm-20-007727795-product_zoom.jpg" alt="laser_module" width="200"/>
* Endmills: 1/64 endmill for cutting the copper, 1/32 endmill for cutting out the PCB
* Material: Single-sided copper board with lamination
* Software: mod
####Protocols and results <br>
**A. Milling part** <br>
1. Use the existing sketches. I used the one called "hello.D11C.serial.5V.1.1" from [here](http://academy.cba.mit.edu/classes/embedded_programming/D11C/hello.D11C.serial.5V.1.1 "test"). <br>
<br><img src="./hello.D11C.serial.5V.1.1.png" alt="laser_module" width="200"/><br>
2. Pick up a copper board.
<br><img src="./copper_board.JPG" alt="laser_module" width="200"/><br>
3. Put the copper board onto the milling machine. It is important to put double-sided tape so that the entire copper board sticks to the base material. In my case, somebody had done it before I used.
4. Set up the 1/64 endmill. Kevin instructed us that one of the common mistake here is to let the existing endmill fall off when you loosen the holder with screw. Holding it tight with my left hand, I carefully replace the endmill by a the one I was going to use. Another common mistake here is to set the z position of the endmill so low that it hits the base material when it starts moving from "home" position to "origin" position. I avoided it by putting the endmill up.
5. Set up the parameters (well, somebody before me did the setting). The 1/64 endmill is so small that it has to go aorund the same route for four times to make sure there is enough space for manual soldering.
6. Mill the copper layer of the circuit. In my first attempt, as you can see below, I forgot to lower the endmill before running the machine. I had to restart the machine by turning off the power. <br>
<br><iframe width="560" height="315" src="https://www.youtube.com/embed/Vj8UQbJwWb4" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> <br>
7. Switch the endmill from 1/64 to 1/32.
8. Cut out the PCB. I saw the residual white-ish power coming up as it mills through the circuit. It was a good sign that the cutting is deep enough to actually keep circuit routes separated.<br>
<br><iframe width="560" height="315" src="https://www.youtube.com/embed/00aqrHuEyXY" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><br>
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**B. Post-milling part** <br>
1. After milling, I first cut the unneccesary copper foils with knife. In my first attempt, I cut too much and damaged the circuit part. Fail! I made another board accordingly.
<br><img src="./fail_1.JPG" alt="laser_module" width="200"/><br>
2. I soldered the components one by one. A good trick introduced by Kevin was to put a solder bit on one end of the component, place the component and solder that end to fix it to that position. This technique was quite useful especially when I was dealing with small parts.
3. Initially, I put too much solder. In this case, I used a brade to remove excessive lead.
<br><img src="./soldering_fail_1.JPG" alt="laser_module" width="200"/><br>
4. At the end, it became like a PCB!
<br><img src="./PCB_complete.JPG" alt="laser_module" width="200"/><br>
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**C. Confirmation parts** <br>
1. Lastly, I checked if each part is properly connected. I used a digital multimeter to check the current one by one.
It looks not bad. I am looking forward to putting intelligence into this chip.<br>
<br><iframe width="560" height="315" src="https://www.youtube.com/embed/2eTidYlKiUk" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
[original files](https://hu-my.sharepoint.com/:f:/g/personal/ttokunari_mde_harvard_edu/Eo_MW5iJhp1GvL7Oqn-jOrYB6G4nvFlrPQ0QWN5hT0okVg?e=J0TZIo "original files") <br>
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