Thanks to Scott for your reply, much appreciated. Are you aware of any new developments in this area? Particularly in respect to the solvents? We are aware that fluorine chemistry is now in-use with amazingly high boiling points. We understand that using forced air convection cannot guarantee adequate profiling thru the entire underside and you will get uneven solder joints. This cannot be disputed at least because of the thermal transfer at each solder point as the air attemts to get under the BGA. We also understand that the use of IR is not good because of the thermal shock thru the entire component. Vapour phase could therefore be a great new/old idea? Onwards thru the fog.... Alan Brewin | | | I would appreciate hearing views on vapour phase soldering particularly in respect to BGA's. | | I know that they used to use CFC's but apparently this is no longer the case? | | Can anyone help with some info? | | Thanks, Alan Brewin | Alan, | Unfortunately, this process is virtually extinct in the US. With the advent of forced air ovens whose thermal transfer efficiencies are great, the cost to produce a vapor phase reflowed joint became prohibitive. There are few, if any, capital equipment manufacturers still cranking out vapor phase gear. | Although the thermal transfer is great within the vapor phase environment, I for one always shied away from the thermal excursion required to go from ambient room temp to vapor temp. Many folks performed a preheat operation prior to reflow. | The fluid is expensive, and equipment maintenance intensive. | I would strongly recommend that you go with forced air convective process. | Scott Cook | scottc@t-com.com
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