Issue link: https://iconnect007.uberflip.com/i/686649
28 SMT Magazine • June 2016 go down to individual PCBs to have the perfect accuracy, even though the individual boards may be shifted or stretched. We also see you need to shoot smaller and smaller volumes. Smaller and smaller volumes need a finer pitch, and it's an ongoing process in our R&D team to make sure that our ejector technology keeps up to pace with the customer needs. It is a challenge. To get those small vol- umes of solder paste is not easy. Las Marias: Do you think that is the end of it? Do you think that there will be no more miniaturiza- tion after that, or will it continue? Bredin: It's probably going to be pushed a little further. It has a lot to do with our handheld electronics. We want to squeeze in more and more functionality in everything. I think it will go on for a while. As it looks right now, maybe screen printing has come to the end of what is doable. That will be a great opportunity when we manage to get the ejector technology to give us even smaller droplets of solder paste. We're al- ready down to class six solder paste. We're very dependent upon the medium and if it is jettable or not. Las Marias: The type of solder matters, right? What about factors like viscosity and such? Bredin: Absolutely. The viscosity is one of the keys, but also we're shooting at approximately 300Hz. So, 300 times per second a piston is hit- ting on the solder paste. It is ejected at a very high speed. For the solder paste to stick together and not splash on the board and get all over the place, it uses a combination of the shooting of the ejector technology and the solder paste. The paste definitely needs to be adapted to with- stand the treatment. Las Marias: What are the key factors that assem- blers should consider when selecting a solder paste dispenser or printer? SOLDER JET PRINTING: KEEPING UP WITH THE CHALLENGES Thomas Bredin