Electronic package sealing is a tricky process. It may seem straightforward: place components in a metal package and seal, generally using projection spot welding (aka cap welding). It is very important, however, to prevent moisture and oxygen ingress to the package during sealing, which, over time, will damage the sensitive electronic components housed within. This zero-moisture requirement is most commonly achieved by heating the package in an oven and then moving it into a glove box backfilled with nitrogen, removing both moisture and oxygen. With increasing frequency, however, manufacturers are starting to use xenon to backfill the packages. Why? Xenon is a large molecule with good thermal properties, and, because the outer valence shell contains eight electrons, producing a stable, minimum energy configuration in which the outer electrons are tightly bound, it is inert to most common chemical reactions, including combustion.
You read that correctly – laser micromachining of metals can be faster and cheaper with fiber laser markers. Their superior beam quality can achieve results similar to traditional machining technologies at less than half the cost! Plus – laser markers can…mark things! Who wouldn’t want one piece of equipment to do several things? And do them so well?
When it comes to resistance spot welding problems, I think I can say I have literally seen them all. I've been in the troubleshooting trenches for years and have worked to overcome weak welds, metal expulsion, and electrode sticking, as well as discoloration and sparking (there are many more!)
A few months ago, a customer came into our Monrovia lab intent on processing application samples using hot bar reflow soldering - the part was specifically developed with that technology in mind. Sr. Lab Technician Vickie Buckley, however, took one look at the part and decided that reflow soldering wasn't the optimum process: the wires were too small and would flatten out before the solder melted and reflowed creating a proper bond on the terminals below. All was not lost, however, her 20+ years of experience told her that the application could be done using thermocompression bonding; they moved over to that equipment and had immediate success! The customer went home content that he had a process that would work!
Flexible circuits are found everywhere: cell phones, tablets, flat screen tvs, cameras, rockets, satellites – anywhere electrical connections are required in three or more axes; where the assembly is required to flex during operation; where weight is an issue; and, as devices get smaller and smaller - where board thickness or space is a driving factor. They are most often connected using hot bar reflow soldering which utilizes a thermode heating element and allows for a more repeatable and consistent joint quality than traditional hand soldering, and are commonly made of two layers of polyimide encapsulating copper traces. Copper trace thickness generally ranges from 0.0007 – 0.004 inches, and thickness of the flex is between 0.001 – 0.0047 inches.