Technical Library | 2019-05-23 10:38:07.0
Solvent and co-solvent cleaning involves the use of engineered solvents in a vapor phase system. The solvents classically used were Class 1 Ozone Depleting Substances, but new types of solvents have been developed that are less environmentally harmful. In some cases, isopropyl alcohol is used with a co-solvent. In these types of cleaning systems, a cloud of boiling vapor solvent is maintained between a boil sump and a cooling coil. When the items to be cleaned are immersed in the vapor cloud, the solvent condenses on the assemblies and acts to dissolve the residues. These processes usually involve a final rinse step outside of the vapor cloud to ensure that all dissolved residues are washed off the assemblies (Figure 1).
Technical Library | 2012-09-13 20:45:17.0
First published in the 2012 IPC APEX EXPO technical conference proceedings. Prior to committing production boards to vapor phase soldering, we performed an evaluation to assess reliability and evaluate the vacuum soldering option. The reliability of vapor
Technical Library | 2014-03-20 12:37:39.0
In the beginning of SMT, Vapor Phase Soldering was the preferred reflow soldering technology because of its excellent heat transfer capabilities. There were also some disadvantages like fast temperature rise, nearly no influence on the temperature profiles and high costs. So the use of Vapor Phase Soldering was reduced to special applications with high mass or complex boards in low numbers (e.g. for military or aerospace use).
Technical Library | 2013-03-27 23:43:40.0
Vapor phase, once cast to the annals’ of history is making a comeback. Why? Reflow technology is well developed and has served the industry for many years, it is simple and it is consistent. All points are true – when dealing with the centre section of the bell curve. Today’s PCB manufacturers are faced with many designs which no longer fall into that polite category but rather test the process engineering groups with heavier and larger panels, large ground planes located in tricky places, component mass densities which are poorly distributed, ever changing Pb Free alloys and higher process temperatures. All the time the costs for the panels increase, availability of “process trial” boards diminishes and yields are expected to be extremely high with zero scrap rates. The final process in the assembly line has the capacity to secure all the value of the assembly or destroy it. If a panel is poorly soldered due to poor Oven setup or incorrect programming of the profile the recovery of the panel is at best expensive, at worst a loss. For these challenges people are turning to Vapor Phase.
Technical Library | 2014-01-30 18:08:04.0
As of today, the electronic industry is aware of the requirements for their products to be lead free. All components are typically available in lead free quality. This comprises packages like BGAs with BGA solder balls to PCB board finishes like HASL. The suppliers are providing everything that is needed. It is harder to get the old tin leaded (SnPb) components for new applications today, than lead free ones. So why has not everybody changed over fully yet and how can the challenges be overcome? A big concern in this transition process is reflow soldering. The process temperatures for lead free applications became much higher. Related with this is more stress for all the components. It affects the quality and reliability of the electronic units and products...
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