As we know, the setting types of reflow welding temperature curve are RSS type and RTS type, but what is the full English name of these two curves? What's the difference?
RSS: ramp-soak -Spike warming - insulation - reflux
RSS type is basically suitable for all types of solder paste, but it is not suitable for water-soluble solder paste, because the tin in the insulation area destroys the activity of solder paste, leading to poor WETTING. The biggest advantage of RSS is to ensure that the temperature difference on the board reaches the minimum value when entering the reflux. If the board has oversized components and connectors, RSS with thicker PCBS is a good choice.
RTS: ramp-to-spike heating directly To reflux, eliminating insulation
RTS is not only suitable for most types of solder paste, it is a good choice for water soluble solder paste. RTS can ensure bright and shiny welding spots, because RTS can effectively protect FLUX in the process of preheating to obtain better WETTING effect. Secondly, RTS is relatively economical for the boss, and a stove with few warm areas can also make RTS, but RSS is not ideal. Also, from the perspective of process window, RTS is much wider than RSS.
The final choice of RTS or RSS is based on the actual product, and the curve setting depends on the type of solder paste.