Reflow2

Roflow oven

Mac Guyver Worldwide Industries presents: The 2nd generation
ATTENTION: This device operates with line voltage (230V). Rebuilding and use at your own risk!

When I was Planning Lena, I realized that I had to use SMD-Parts which aren solderable with ‘normal’ hobbyist-tools. So I decided to Build a reflow oven on my own. I was also enspired by a magazine called ‘Elektor’.
Well, the Results didnt turn out so well, so I found a sponsor who soldered the Lena-Hardware for me. But the reflow-project is not dead!

I used a hot air gun which i got at the hardware store for ~ 40€. After I reverse-engineered the PCB (that they are allowed to sell something like this…) I hacked another motor into the gun to be able to control it whith my electronic. I also added a additional overtemperature-fuse as well as a additional Pt1000 temperature sensor which measures the outside temp of the teating-coil assemlby.
The hot air gun has a power of 1600W, which should turn out as a average power-density of about 266,6 W * l^-1 (compared to the previous 120 W * l^-1).

I installed an additional thermocouple to measure besides the PCB-temp the air-flow temp as well. But I was unable to hook up the second MAX6675-PCB with the I²C-Interface.

When the first firmware was complete and flashed, I tried the oven. But it didnt work very well. The heat gun was far to less powerful to heat up the board in a proper time.
But, except the fact, that the heat is not distributed constantly, it turned out, that the copper oxidizes massively. In principle no great discovery, I thought of this problem before, but it was just too massive. The copper turned red, and because I normally don use PCBs with solder resist, this
is very very bad news.

these discoveries led to a complete redesign, with hot-air-solderiron-heating-elements and Argon, which I WILL describe here?.

Files:

• PCB-layouts as TARGET3001! (V10) files.
• Firmware for the Thermocouple-PCB with MAX6675, ~AtMega8 and I²C Interface (AVR C (WinAVR))

If you have questions, problems dont mind emailing, but please note however, that I dont use Target 3001 anymore.
The project is released under a GPL license.

Pictures

The whole oven.

This is the Mythbusters-style heatgun assembly.

some hacked cables.

On the left there is the second thermocouple the old one is in the middle.

…in detail…

Thermocouple-cable.

Thats it 😉