Drying in the vacuum

At Siemens AG in Fürth, the drying time in the cleaning of heavily polluted electronic/electromechanical assemblies was reduced by more than 13 hours through the use of a vacuum drying oven. Before the electronics assembly is stored in the vacuum oven for drying, it passes through an ultrasonic bath containing detergent and is then rinsed for two to three minutes with tap water. Before the actual drying process, waterdrops are blown away with compressed air.

The new drying procedure in a vacuum drying oven:

• Drying the electronics assembly in a Memmert vacuum oven VO at approx. 60 °C and 14 to 16 vacuum drying cycles (always alternating between 50 and 900 mbar)
• Drying time approx. 2 to 2.5 hours

The drying procedure before in a conventional drying oven:

• Drying the electronic assembly in a conventional drying oven at approx. 60 °C with an air fan at maximum speed and air flap completely open
• Drying time approx. 16 hours

Electronic components: Storing und drying in the vacuum drying oven

The Printed Circuit Board Industry Association (VdL)/ Electronic Components and Systems Division within German Electrical and Electronic Manufacturers’ Association (ZVEI)-Working Group “Qualitymanagement” recently published recommendations and guideline values on “Drying bare Printed Circuit Boards” and “Storage conditions for bare Printed Circuit Boards”. The recommendations also refer to a considerably shorter drying time in the vacuum – thereby reducing energy consumption as well.