Lead-free component conversion

There are several factors related to business operations that must be considered when contemplating the conversion to lead-free components and processing. A separation of parts with the same leaded and lead-free configuration must be maintained, bills of materials (BOMs) must be managed, and components and materials distinguished, with each customer and supplier working to a different transition schedule. 

Defect detection where rework is easiest, before component placement and solder reflow Process characterization during the lead-free conversion with minimal program tuning... 

The mandated conversion to lead free assemblies has led to the convergence of several critical issues in the microelectronics industry. The conversion has further compounded several other factors that have been pushing the envelope in Component to Printed Wiring Board (PWB) reliability, including... 

Effect of Lead-free Conversion. The impact of un-optimized pad size selection is detrimental to both tin-lead and lead-free assemblies. Fine pitch components (<0.8 mm pitch), regardless of solder metallurgy are much more prone to pad size-related failures. 

The next critical component for this material was the development of the flux and activator system for the paste. This proved to be a key factor in the success of this project. As the wettability of lead-free alloys is lower than eutectic Sn-Pb, a suitable flux system was critical to the successful introduction of the MD s conversion to lead-free. In addition to the flux system having the properties to promote wetting, the requirements for screen printing, stencil life, tackiness, and so on were also important when evaluating a solder paste system. Flux technology is discussed in... 

FIG. 76 Photo of Visteon s lead-free conversion product, a) Photo depicting panel with 5x6 array of cards, b) Single card fully populated with components. (From Ref. 36.)... 

C. IBM and the Conversion of High-Complexity SMT Components to Lead-Free Technology... 

With a market interest rate of 15% and a general inflation rate of 5%, the inflation-free rate is 9.52%. This leads to a net present value of 63,480.63, which is equivalent to the actual doUar analysis (within rounding error). This is expected because all of the component cash flows were inflated at the same rate. As noted in the before-tax analysis, if the component inflation rates differ, then there may be a discrepancy in the final net present value analysis because the conversion from a market rate to an inflation-free rate (or vice versa) requires a single inflation rate. 

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