Week 3 Assignment: Electronics Production

Mill and stuff an in-circuit programmer that includes a microcontroller.
Test to verify that it works.

The group assignment for this week was to mill the design rules of the end mill. This entailed milling the .png file shown to the right, which mills progressively smaller and smaller traces and gaps ranging from 1 to 20 mils.

The design rules demonstrate the tolerance characteristics of the machine, the end mill, and the material being milled. It was found that in the mill's current state it was able to produce traces as fine as 7 mils. As shown in the image to the left, traces finer than 7 mils had a tendency of pulled up, specifically at the termination of the trace. The milled design rules also demonstrated that gaps have to be at least 16 mils wide to ensure milling, which correlates to the diameter of the 1/64 in end mill being used (15.6 mils).

Determining the required components based on the schematic of the programmer was a good exercise in component identification. As a note to myself and others, it is always prudent to verify operability of components prior to and after installation (.e.g., checking continuity of a 0-Ohm resistor to verify it is not open).

This was not my first experience soldering components onto circuit boards, but I still consider myself a novice in this field. Using a soldering iron and solder wire I first attached the microcontroller and the male jumper connector. This resulted in solder points with a shiny appearance. To assist with lining up components I transitioned to first using a small amount of solder paste to tac components into place, followed by using solder wire to create a more sound connection. I felt as though I was maintaining consistent heating between the component and the board, but this procedure resulted in cloudy solder points. I question the expiration and/or compatibility of the solder paste with the solder wire. After adhering all components, I used a multimeter to ensure I do not create any shorts between traces and verified continuity throughout the board.