Loading... Please wait...

Our Newsletter


Lead Free Soldering

Search Categories : 3M  | R&D Technical Services | Branson Ultrasonics

FREE TECHNICAL SUPPORT ON ANY VAPOR PHASE LEAD FREE SOLDERING APPLICATION !!!

Lead Free Soldering refers to the technique of reflowing solder compounds that contain no lead.  Driven by Market forces in Europe in 2002 (WEEE and RoHs),Lead Free Soldering in the US is finally catching up with Europe - without any legislative mandate in the US!  Classically the world used SnPb alloys that reflowed at 215˚C.  At those temperatures, most components were able to survive multiple passes in a process with no deleterious effects.  Lead free alloys require temps in the range of 225-245˚C to reach an ideal liquidous phase.  In order for all the parts in a board to reflow properly, it is not uncommon for a board to make 6 or more passes thru an air reflow oven at ever increasing temperatures - up to 265˚C!!  One slick way to avoid overcooking parts on your board is to reflow using Vapor Phase Reflow (VPS) Technology.


Founded in 1996 to support the vapor reflow market, R&D Technical Services is the leading source of vapor phase equipment. R&D Technical Services’ vapor phase systems are used in numerous markets including SMT solder reflow, selective component rework, lead-free soldering, curing, drying, mechanical attachment, plastic package testing and more. 

 

screen-shot-2011-03-06-at-1.21.39-pm.jpg

 

Vapor Phase allows the user to close the window between solder reflow temps. and process temps.  A solder that reflows at 221 C* can be easily processed in a 230 C* vapor with no risk of overheating.  Using VPS by R&D Technical Service, the condensation of the working vapor to the part transfers uniform heat with little regard to mass of product uniformity throughout the condensation process.

screen-shot-2011-03-06-at-11.30.33-am.jpg

In past few years, there has been an ever-growing importance of what is called Design for the Environment (DFE) and Green Manufacturing.  Both emphasize the use of environmentally benign materials so that the environment is impacted as little as possible.  

Lead-containing solder has been standardized and used for over 65 years as the principal joining material for Level 2 packaging defined as attaching component level packages to a suitable substrate to produce printed wiring assemblies (PWAs).   A number of factors have contributed. Lead-free solder has certainly played a role. The higher melting points of lead-free solder have forced many reflow methods into uncomfortably high temperatures. 
 
Unable to transfer heat as effectively and consistently as vapor phase, manufacuters were forced in some instances to push maximum temperatures to unacceptable levels. They are simply were unable to close the window between reflow and peak temperatures as efficiently as vapor phase, which can place reliability and consistency at risk.

The more difficult the components, the more successful the VPS process is. All these factors have played a role and board architecture also has played a part. More densely populated boards and more demanding components lend themselves to much easier reflow using vapor phase and its condensation technique.


tin-whiskers-01.jpg

When faced with WEEE or RoHS challenges, only Vapor Phase Reflow can Address all the issues without driving the Production Manager crazy. 

Lastly, Because conventional techniques require the board to be processed at temperatures in excess of 260˚C in order to reflow that certain BGA.  The result is a very challenging board to clean.  Because VPS is done in an inert atmosphere, the surface soils that remain after VPS reflow of Lead free solder is way easier to Clean. 

 

AMS - Hi-Rel Lead-free assy_SMTA