The boards I ordered recently arrived and it was time for assembly. Because I am designing for minimal cost, I had to hand solder the accelerometer and gyroscope. Both were QFN packages so I couldn't simply use a soldering iron for the job. Instead I needed to learn how to use soldering paste and do basic reflow.
|The boards from SeeedStudio.|
So I talked to a couple people and they suggested hot air rework. The problem was I didn't have a hot air rework station and didn't feel like shelling out $100 for one. So when I went to Fry's electronics to buy some soldering paste, I saw a $14 personal skillet and I remembered this great tutorial from SparkFun
. They found that a skillet is a fitting alternative to a toaster oven and in some ways works better. I decided to give it a try and I wasn't disappointed.
|The skillet from Fry's. Only $13.99!|
|Cooking up some electronics!|
The most difficult part of the process was applying the soldering paste since I didn't have a stencil or syringe. Instead I used my pair of tweezers to "paint" it on the pads which I wouldn't recommend. It worked, but it was tedious and messy. (I have since ordered a syringe). After adding the parts to the board, I simply laid it on the skillet and watched as the parts reflowed and slid into place. Everything seemed to reflow fine save a one or two solder bridges which were easily fixed with a soldering wick.
|The board after reflow. You can see some small solder bridges.|
One disadvantage of the skillet method (and toaster?) is that you can only reflow one side. This meant that I designed my board with all of the reflow parts on top so I could hand solder the bottom. This wasn't too hard as I only really had to solder the microcontroller which is pretty easy with the help of soldering braid.
|The hand-soldered bottom of the board.|
The end result looked great and I was really pleased with skillet reflow. It was fast, cheap, and easy to do! Check out my next post where I will show how I tested the boards.
|The finished product.|