Characterization of the machine and tools¶
Assignments¶
Before milling the FabISP board, we had to characterize our machine named the OtherMill. To do that we will use the linetest.png file to find the best way to mill correct PCB and how thick the traces of the PCB can be.
- Described the process of :
- milling
- testing
- Find the correct workflows
- Explain your choices
Characterization¶
To characterize the machine and find the right parameters, we mill the linetest.png file.
To do this with our machine, we need to modify the file an transform it to svg. We’ve done that with Inskcape.
Tip
To make a correct file for the Othermill software, it has to be saved in simple .svg and in mm. If not, the file will be to big because it will covert the px in mm.
How to mill¶
| Find some thick tape | Tape your board | Put it on the machine |
|---|---|---|
 |
 |
 |
Open you files into the machine software. You should now have a new panel with your board in the right of your window. In that panel you can place precisely your board by modifying the placement value. It’s interesting when you want to mill more than 1 board at a time for example.
You can also add your milling tools. For our tests, we will use 1/64 and 1/32 Flat end mill.
You will have to select your material. Here we used “Single-side FR-1” material.
After that, you normally put the thickness of the material. There are two way to determine the thickness of your material :
- Manually : By measuring the thickness of the board
- Automatically : By using the probe system of the software.
We have tested the two way for our tests, and also, we have modified the engraving depth. Here are the results :
| Test n° | Material Thickness | engraving depth | Image |
|---|---|---|---|
| 1 | 1,54 mm | 0.15mm |  |
| 2 | 1,55 mm | 0.12mm |  |
| 3 | (probing) 1,76 mm | 0.10mm |  |
| 4 | (probing) 1,76 mm | 0.12mm |  |
About probing material thickness¶
To make the tests number 3 and 4, the machine automatically probe the thickness of the material using the option BitBreaker -> Probe material thickness . to do that, you have ta add a piece of metal between the copper of the board and the metalic frame of the machine. The machine will move on the Z axis until the tool touch the copper. With that technic, the machine can automatically know the thickness of the material.
Results¶
So for our PCB milling, we will use the parameters of the test 3 which make the best and clean cut during our first milling project.
