Paste Printing
Overlooked Features of Stencil Printers
Some PCB assemblers opt not to use vision inspection and other major stencil printer features, as well as setup process techniques. Yet several problems can occur if a vision inspection isn’t deployed.
by Alex del Rosario
Cover Story
Tin Whisker Observations
Tin whiskers are known to be a hairy problem, with the potential to cause transient or catastrophic electrical short circuits. Here, Raytheon and industry colleagues reveal the observations and SEM images of tin whiskers captured during a series of investigations and experiments aimed at better understanding their growth, evaluating associated reliability risks, and developing mitigation techniques.
by Robert R. Ogden and Robert F. Champaign
Process Control
Minimizing Solder Paste Printing Variation
Research into printing process factors finds the stencil blade angle affects the overall time the paste spends over the aperture, as well as the maximum filling pressure. Both characteristics have a significant effect on the resultant aperture fill.
by George Babka