Connor Holowachuk | Project personal-reflow-oven

Project Overview

A private project which was initiated by the aspiration to build circuits that make use of SMT components. A home-etched control circuit, comprised of high power SSRs, an IR thermal sensor, and an ATMEGA-328P bootloaded with Arduino, was used to control the heating elements of an inexpensive toaster oven and follow the appropriate heating curve for the solder paste to set correctly.

The Improved Toaster Oven

Toaster ovens might be good for pizza, but they're even better for baking PCBs. I used the body and heating elements of a toaster oven to create a reflow oven, with an added IR temperature sensor mounted on the top to measure the temperature of the PCB.

Chemically Etched PCB

Before I ordered my first PCBs from a fab house, I chemically etched my own PCBs to test the reflow oven. This involved designing the routes in Eagle, transferring it to a transparency sheet, using an iron to transfer onto a copper clad board, and then using it to etch the PCB in a hydrochloric acid + hydrogen peroxide solution.

Logic Gate 7-seg Display Driver

I designed a 7-segment display driver using logic gates to display the temperature of the oven. When counting up, a single ping from the Arduino would count the temperature up by 1 degree. When counting down, 999 pings would reduce the temperature by 1 degree.

Baking a PCB

After using a solder stencil to apply the solder paste and components were placed on the PCB, the PCBs were placed in the oven and baked according to the solder paste reflow heating curve.