With the powerful processor, it is relatively easy to develop a user interface using the TouchGFX library, which is now free. Rather than using an Arduino, I’m going to be using the board with the STM32F746 Discovery kit that includes a 4.3” TFT touch screen. In this article, I’m going to build an Arduino-style shield for running the vapor phase reflow oven I’m working on. The Galden liquid is relatively expensive, but the quality and repeatability of vapor phase are worth the price. It turned out for small batch production, there really isn’t much to the machines mechanically or electrically, so I could potentially build a machine for very high quality reflow soldering in my office without much effort or expense.
Late last year, when I was trying to buy a toaster oven to convert to a reflow oven, I started looking at what would be involved in making my own vapor phase reflow oven. Most vapor phase reflow ovens cost almost as much as a multi-zone conveyor oven that can handle orders of magnitude more boards per hour, but the ones from Imdes are far cheaper. Fast forward to a few years ago, and there was a discussion on the OpenPNP group about reflow soldering methods where someone had a relatively low cost vapor phase reflow oven, which again got me interested in vapor phase soldering. They were mostly working on specialized aerospace/military and mining boards that had strict requirements that the assembler told me were easier to meet with the vapor phase reflow process - this gave me my initial spark of interest into vapor phase reflow soldering. Some of my first commercially manufactured boards were made by a small assembler who only had a vapor phase reflow oven rather than the large multizone convection ovens you see in most assembly lines. The high power LED panels did not look like they would fit into the toaster ovens I was looking at, or if they did that there would be enough heat to prevent defects. Another factor that I had to consider was the size of the oven as I’m working on a high power LED panel project, and a couple of other LED panels which will be on metal core boards. Initially, I was looking at converting a toaster oven to run picoReflow, and building a Pi Hat for the required electronics but I was finding that a good convection toaster oven on Amazon was starting to look rather expensive for the quality of work it would do.
With all the projects I’ve been working on, I want a better way to do reflow soldering during board assembly than just using a hot air rework station.