Today, I tried to master SMD soldering, but it didn’t went as expected. The first board I soldered I did by hand, which was a tedious job which required many tries, but in the end, it worked. However, I wanted a more simple way of soldering boards as I may need more boards in the future or as I just want to know that I can put together the final product. To do this, I used the stencil I bought from PCBWay and some solder paste. To put the solder on is not easy but also not impossible. After some practicing I knew how much paste I should apply, with what pressure, and other useful skills like focusing my eyes really short distances…
The first “batch” went into the oven, at 300 degrees Celsius. This is too hot as the solder paste has a melting point of 217 – 220 degrees. The human errors I made did not stop there, I also forgot it there, in the heat. I got a reminder when I saw white smoke coming out of the oven, tt turned out that the PCB had totally melted and could not be saved.
For the next try, instead of an oven, I used a torch to melt the solder paste. This way, I can see when the solder has melted and then remove the torch from the PCB. However, this did not work either; as the solder paste melted nicely, as so did the connector. And even if it haven’t melted, some of the pins had too much solder on them and where connected with each other.
So I really don’t know what to do next. I could still continue develop the prototype but I would have problems with moving on to a final product.