Editing Reflow soldering (section)

==Cooling zone==
The last zone is a cooling zone to gradually cool the processed board and solidify the solder joints. Proper cooling inhibits excess intermetallic formation or [[thermal shock]] to the components. Typical temperatures in the cooling zone range from {{convert|30|-|110|C|F}}. A fast cooling rate is chosen to create a fine grain structure that is most mechanically sound.<ref name="indiumcorporation"/> Unlike the maximum ramp-up rate, the ramp–down rate is often ignored. The ramp rate is less critical above certain temperatures, however, the maximum allowable slope for any component should apply whether the component is heating up or cooling down. A cooling rate of 4&nbsp;°C/s is commonly suggested. It is a parameter to consider when analyzing process results.