My name is Meagan Sloan and I have recently joined the technical support engineering team at Indium Corporation. In my short amount of time here I have learned things I never knew existed. I now know that solder is everywhere! Look at your cell phone. There are soldered connections in there making electrical, mechanical, and thermal bonds, which allow your phone to work. It's amazing how some metal and flux can make a connection that has driven us into the modern age of electronics.
I was recently involved in writing a paper for SMTAi called “Reflow Profiling for Next-Generation Solder Alloys.” For the paper, I had to research reflow profiling. I found out that there are two general profiles that are used. The first is ramp-to-peak (RTP), also known as ramp-to-spike; the second is a soak profile, or ramp-soak-spike (RSS). The peak temperature is the highest temperature that the profile reaches. The RSS profile has a soak section in the profile. This soak looks like a “plateau” followed by a spike to the peak temperature.
A soak profile can be used for PCBAs that have a large heat differential across the board. This is used more for really thick printed circuit boards that takes a long time to heat up to the same temperature across the board. A ramp-to-peak profile can be used to minimize oxidation of the solder powder to reduce graping.
Stay tuned for more from me about what I am learning at Indium Corporation.