Cooling of wash-tight relays

After wave soldering, the assembly must be cooled down as gently and stress-free as possible to the desired low and constant temperature in a cold air flow before the washing process. If a washing process follows, this temperature must be matched as closely as possible to the temperature level of the washing medium. The optimum cooling gradient for this must be determined individually for the relay or the assembly under original process conditions. The recommended cooling gradient is in the range of 0.5 K / s to 2.5 K / s. As part of the qualification of the assembly, the optimum cooling process must be determined and used as a basis for processing. This avoids possible damage, such as micro-cracks on the relays (and also other, neighbouring components). Too rapid cooling or sudden temperature changes, which could have an effect on the assembly as a cold shock, must not take place.