Technical Library | 2007-08-16 13:34:31.0
While experienced inspectors may be able to determine the aesthetic differences between a lead-free PCB assembly and a tin-lead version, one cannot rely on the "experienced eye". "Less wetting out to the pad edges" (Figure A) and "graininess and lack of shininess of the solder joint" (Figure B) are typical comments about some lead-free solder joints. However, in cases where a Nitrogen atmosphere was present during the reflow of the solder joint (Figure C), there will be little visual differences between the lead free alloys and their tin-lead counterparts.
Technical Library | 2007-01-31 15:17:04.0
The goal of this project is to evaluate the reliability of lead-free BGA solder joints with a variety of different pad sizes using several different BGA rework methods. These methods included BGAs reworked with both flux only and solder paste attachment techniques and with or without the use of the BEST stay in place StencilQuick™. The daisy chained test boards were placed into a thermal test chamber and cycled between -25ºC to 125ºC over a 30 minute cycle with a 30 minute dwell on each end of the cycle. Each BGA on the board was wired and the continuity assessed during the 1000 cycles the test samples were in the chamber.
Technical Library | 2007-05-02 15:00:17.0
This brief study of lead-free wave soldering focuses upon copper dissolution and solder maintenance issues. Unfortunately, it is determined that waste and changeover costs can dramatically increase with lead-free wave soldering.
Technical Library | 1999-05-09 14:14:51.0
With the ongoing concern regarding environmental pollutants, Iead is being targeted in the electronic assembly arena. This paper highlights lead-free solders and the different combinations of elemental makeups.
Technical Library | 2009-06-11 19:27:21.0
The shock reliability of solder joints has become a major issue for the electronic industry partly because of the ever increasing popularity of portable electronics and partly due the transition to lead free solders.
Technical Library | 2009-04-09 20:43:09.0
Evidence has come to light that increased solder process temperatures, specifically for lead free solder, are dramatically shortening life expectancy of components; failures do not show up during initial test, but much later on in the products life,
Technical Library | 2008-02-12 22:52:41.0
Corrosion of solder pots and solder pot components in wave soldering equipment has been reduced with the introduction of corrosion resistant coatings and improved lead free solder alloys. The latest trends in protecting wave solder machine components from liquid metal corrosion by lead free solder alloys will be presented in order to provide guidelines for evaluating existing equipment as well as for purchasing new systems.
Technical Library | 2009-06-02 23:53:18.0
Today the lead free soldering process is a must in commercial electronics and it is also coming more and more important in automative and industrial electronics sectors in the near future. The most common choices for lead free solders are different Tin-Solder-Copper (SAC) alloys. Processes using SAC solders cause extra stress, because of increased process temperatures, especially to the plastic materials.
Technical Library | 2015-02-12 13:32:52.0
Market forces, particularly legislation against the use of lead in electronics, have driven electronics manufacturers towards lead-free solders for PCB assembly and rework. This approach creates challenges because of the relatively high temperatures needed for lead-free soldering. Additionally, lead-free solder alloys typically do not wet or wick as easily as Sn63Pb37 leaded types. As PCBs often include both BGAs and simpler discrete devices, a lead-free rework capability should include a suitable soldering station and a BGA rework station. This article shows how such equipment can be adapted to overcome the lead-free issues and provide a successful reworking facility.
Technical Library | 2014-05-12 15:32:17.0
The issue of lead-free soldering has piqued a great deal of interest in the electronics assembly industry as of late. What was once an issue that seemed too far away to worry about has become a pressing reality. In order to avoid confusion, last minute panic, and a misunderstanding of how the issue of lead-free soldering will affect the industry and individuals users of solders, it is necessary for all suppliers and assemblers to become educated in this matter.
