Etching of a test circuit board

Published: 15.04.2019
To test our inertial measurement units, we had to etch our own test boards, so we can connect the chips to a microcontroller. This is a big step towards the final development of our rocket’s MCB.
Etched and galvanized FR4 Etched and galvanized FR4

Why the effort?

On April 15th2019 we created our first circuit board. As the LSM6DSOX inertial measurement unit we use hasn’t hit the hobby market yet, we had to produce our own board so we can connect the sensor chips - which are just a few millimeters big - to an Arduino. We then can run first test programs to communicate with the sensors.

The manufacturing process

We etched a 35 µm copper layer of a FR4 board. We printed our negative for UV-exposure onto transparent foil and stacked two layers on top of each other to make it less translucid. After 95 seconds of etching we electro-galvanized all copper surfaces. For simplicity reasons, we passed up on using any kind of solder resist, as our circuit board will only be used shortly as a prototype. The reflow soldering of the SMD components is expected to be done before June, but is dependent on the delivery time of the sensors.

We would like to thank the staff of the AVT-laboratory at the TH-Nuremberg, who enabled us to produce this prototype.