Week 8

Assignment - Electronics Production

  • Group assignment:

    • Characterize the design rules for your in-house PCB production process: document the settings for your machine.
    • Document the workflow for sending a PCB to a boardhouse
    • Document your work to the group work page and reflect on your individual page what you learned

  • Individual assignment:

    • Make and test a microcontroller development board that you designed

From Assignment Details.

This week I am making a QPad, as documented by Quentin: https://quentinbolsee.pages.cba.mit.edu/qpad-page/ I am hesitent to try the one I made in Week 6, because I haven't tested it yet. I will test and retry.

As advised by my instructor, I doublechecked the type of OLED screen! Order was GND - VCC - SCL - SDA, so no change needed fortunately!

Equipment:

  • Bantam Mill
  • Solder Station (with Hot Air Gun)
  • Tweezers
  • Various Components
  • FR4 (two sided copper)
  • Flux
  • Laptop (using Mods and Bantam Mill software)
  • PPE, and extraction (Festool vacuum)

Attempt 1

Bantam Mill, Setup

Measured to be 126 x 101 x 1.6 mm. This is not including the sticky tape: 1.7mm.

Measure The Material

Stuck down the material with double-sided tape.

Material Sticky Tape

Bantam Mill, Toolsetup

Tool Change

Bantam Mill, Homing

Go to File Setup, and New CAM to load your Gerber files.

Bantam Mill, Gerber Files

Bantam Mill, Offset

Offset by 2mm in X and 2mm in Y, but tool was 1/8" so the outer profile still cut to the edge.

Remember to Generate All Toolpaths again.

Bantam Mill, Render

Result of attempt 1

To cut, I selected Mill All, and activated the extraction. The tool lowered and spun up. Initially it only cut the toolpaths for the 1/32" flat endmill, and paused. This was less than I expected. I stopped the Job, and changed the tool to the 0.003" engraving bit, which fit into the traces now. I changed to the 1/8" flat endmill for holes and cutout.

I didn't notice that the render didn't include throughholes for the OLED screen. To make the most of this test, I will try to make the holes with a dremmel and a 1mm bit. The pads are probably tight for this, so it's not a good solution.

...

Note 1: Added the through-hole drill holes (and it damaged a trace)

USB Microscope


Microscope Screenshot

It still worked on the continuity test.

Continuity Testing

Note 2: Resisters I had were not the right form factor.

* As a remote student, I thought I could use the sample book of SMD resistors. They turned out to be 0402's instead of 0805's, and thus could not reach the intended pads.

SMD Sizes


Resistor Book