ASSCON MultiVacuum vacuum soldering process

ASSCON’s invention of the vapour-phase vacuum soldering process has set a milestone for industrial electronic production, according to the company. The vacuum soldering process has proved a successful solution for constantly challenging soldering tasks while process windows were getting continuously smaller.

In the MultiVacuum process, PCBs are subjected to several vacuum applications during the soldering stages, with the option of applying vacuum both before and during the melting of the solder paste.

Applying vacuum before the liquidus temperature is reached is particularly useful for removing any voids encapsulated and caused by printing or pick-and-place processes — eg, while scooping out the soldering paste during the printing process — even before the soldering paste is molten. This way the voiding opportunity is eliminated before the heating process is even started.

The process also enables void-free solder joints where products with an above-average outgassing opportunity are concerned (eg, a high number of layers in multilayer, large processors). Gases entering the solder joint in a first vacuum stage can additionally also be effectively removed from the still liquid solder joint in subsequent vacuum stages.