Tecnology

Vapor Phase Welding (vacuum)

The Vapor Phase welding system is based on the physical laws of heat transfer through vapour. This type of process ensures, almost automatically, the highest possible product welding quality.

Vapor Phase welding guarantees in fact excellent temperature uniformity. It’s the best technology for welding complex elements – such as BGA, QFP, QFN, POP -, in boards densely populated with a wide range of components.

Vapor Phase welding is also extremely suited for welding devices requiring power dissipation (for example power LED diodes), as with the Vapor Phase technology the presence of Voids (air bubbles) is reduced by 99%.

Description of the Vapor
Phase welding process

The Vapor Phase welding process – vapor condensation -, consists in bringing inert fluid to boiling temperature. This creates a “layer of vapor” (zone) where, after a pre-heating stage, the “assembled” component will remain for the time strictly required, ensuring extremely even welding. The vapor-board heat transfer occurs during the condensation stage. This process is slightly longer than conventional air systems, requiring between 6 and 7 minutes, against the usual 5 minutes of air systems.

What are the advantages of welding a board using
Vapor Phase welding technology?

  • Vapor Phase welding is extremely reliable and has numerous advantages when compared with conventional welding systems.
  • With this technology, there cannot be “temperatures” out of control on the assembled board, as the boiling point of the inner fluid (Galden) will be at a precisely set temperature.
  • The thermal delta among the various components of the board is normally within 3 degrees centigrade, including for components of small sizes (passive).
  • Thanks to their heat transfer efficiency (the condensation principle guarantees transfer up to 10 times more efficient when compared with forced convection systems, either air or nitrogen, and up to 50 times when compared with infrared systems), Vapor Phase systems allow great energy savings and very low operating costs.
  • This welding technology is not affected by the sizes of the components, by the masses and weights or different colours of the devices found on the assembled product. Irrespective of shape, size, weight and colour, each component will reach about the same temperature
  • Absence of oxygen: Vapor Phase welding means an environment “without oxygen” (with all the benefits that it entails). With this technology, NO nitrogen is introduced to obtain an “inert atmosphere”. Also this is undoubtedly a very important source of savings.
  • The absence of oxidation phenomena (as a “consequence” of the above) allows better wettability of the joint and the alloy, and therefore better welding joints, with superior mechanical resistance. The temperature is at least 15/20 °C lower when compared with traditional convection ovens, with a reduction of thermal stress for all the board components.
  • No tests and dedicated welding profiles are required: even the first and only board prototype, in case of only one, will be perfectly welded.
  • Minimization of board delamination phenomena: by processing the board at a lower and more even temperature, the risk of mechanical deformation will be reduced. Delamination problems due to humidity in the circuit are also reduced. (as an example, the humidity found in the Pcb at 245 °C can exercise a force up to 40 bar, while the same humidity “trying to leave” the Pcb” at 230 °C will have a force of approximately 28 bar).
  • Repeatability, uniformity and homogeneity of the welding temperature (absence of shadow effects).