Condensation oven

OVERVIEW

In August 2002 the assembly workshop put in service a new condensation oven. With this oven all SMD components, including Ball-grid Array (BGA) components can be mounted. The advantage of a condensation oven compared to other techniques such as infra-red soldering is that the temperature profile is very precise and even over the full area of the board to be mounted. The PC-controlled oven can handle boards with sizes up to 550 by 450 mm, which fits for example easily  9U (367mm) by 400 mm VME64x boards.

A condensation oven is an hermetically closed oven in which a liquid in vapour-phase form is used to transfer the heat to the components and solder. With such an oven, it will be easy to move to other solder-types, such as lead-free solder. Lead-free solder has a higher melting point than conventional types. As the components should not raise too high in temperature during the reflow, it will therefore not be possible to raise the temperature much more than 15 °C above the melting point, while before a margin of up to 40 °C was used. To give an example, SnPb-solder is normally soldered at a temperature of 200 °C, while for lead-free solder a temperature of 230 °C is used (with another type of liquid in fact).

In case SMD components should be mounted on both sides of the board, it will be done in two phases. First the side with the least sensitive components will be mounted and soldered. After that, the components for the other side will be mounted and then the solder on both sides will reflow, effectively melting again the solder on the side that was mounted first. This has no impact on the quality of the final product. Through-hole components will be mounted afterwards by hand.

The difference between a condensation oven and a vapour-phase oven (which is the type CERN had before) is that in a condensation oven the vapour is only created when it is needed and is condensated afterwards, therefore saving the environment.

DOCUMENTATION

CONTACTS