Issue link: https://iconnect007.uberflip.com/i/1526114
12 SMT007 MAGAZINE I SEPTEMBER 2024 tions, you can always step stencil, which has been a practice for a long time; however, it causes some process challenges such as solder deposit uniformity and inspection accuracy. If you had both pieces of equipment (stencil printing and jetting), you could then do additive manufacturing and essentially jet the paste on top of your three-mil height, which was depos- ited through the stencil, to get more solder vol- ume before placing the connector in place. If you factor in additive-manufacturing think- ing to solder paste application to get a cer- tain height, does that become a design con- cern as much as an assembly concern? Murling: Nolan, everything's heading toward miniaturization. You're having these auto- motive manufacturers get into the space, and they're not able to find those larger parts that they're comfortable working with anymore. Everyone's focusing on the smaller devices. ey're more readily available with the same power output, but they still need those con- nectors. You will need a step stencil, or you could do the additive approach. Ron Lasky: Adam, isn't jetting a niche thing? It's not something that 20% of assemblers will do. Or am I wrong? Murling: It's definitely a solution for specific needs. One place is in some government work, where they only need to build a few boards here and there. roughput is a key consider- ation when deciding whether to go with print- ing or jetting. Lasky: If you have an application where you will only build, say, five boards, you won't really need to worry that jetting is a slower process. It's very flexible and can do just about anything, but it's very slow. So, if you're only building five boards, then who cares about the time jetting might take? If you're building a million smartphones a month, however, then jetting is just too slow and you will need to use stencil printing. Is that where jetting wants to be filling a niche or a specific need? Or are the jetting manufacturers trying to move forward into something more production-capable? Murling: I'd probably defer to the manufac- turers for that answer. But jetting is also very useful in R&D labs when they're developing boards and processes, because they're super flexible, as Ron mentioned. So, they're also using the R&D side. Lasky: In the 1990s, a dispenser manufac- turer—which dispenses and gives essentially the same result as jetting—always hoped they could make their process more mainstream to replace stencil printing applications. e great limitation, as we're discussing, is that it's slow, and the curse of manufacturing any- thing in high volume is a slow process. ey've done a lot of work to make the process faster, but they can't compete with printing in most cases. It is important to point out that there are some jobs that only dispensing or jetting can do, such as underfill for BGAs or CSPs, among others. We don't want to minimize the impor- tance of either jetting or dispensing, but they won't replace common stencil printing pro- cesses. Adam Murling