Issue link: https://iconnect007.uberflip.com/i/1207026
46 SMT007 MAGAZINE I FEBRUARY 2020 for any stencil buyer to be educated about this whole thing. It's surprising how much of the focus is on price rather than quality control. Johnson: What should an EMS provider ask their stencil vendor? Schmidt: An EMS provider should ask the pro- vider what quality tolerance they provide in the first place and what type of equipment they use because many stencil providers have a variety of different systems in operation. If I were a buyer, I would want to make sure my stencils are always made on a certain piece of equip- ment with a specific quality standard since dif- ferent systems come with varying quality lev- els. The secondary issue is how the data is being managed. Is the data being manipulated after it's being transferred to the provider for "optimi- zation" that the EMS com- pany may or may not have any influence on? Or is the data is fully under control of the EMS company and not being changed by the stencil supplier? These are things that the EMS compa- nies should have a vested interest in. Holden: Do you have a machine that could both depanel boards and cut stencils? Schmidt: No, those are two different processes. Stencils are a tool for the beginning of the line, and then we have a depaneling machine that's at the end of the assembly line. They use dif- ferent methods. Although they both use lasers, that's the only general thing that they have in common. That's where the similarities end. Holden: It would be nice if there was one machine that did both because the stencils are kind of at the beginning of the process, and if the machines at the end do depaneling, then it would be pretty high payback in terms of the active use of the machine. Schmidt: Absolutely. However, the challenge that we have with this is a laser that's a specific tool. The lasers that are used for cutting sten- cils and metals fast with high qualities use a dif- ferent process. That process is called the melt and blow process. This is the technology that's being used for cutting sheet metals versus the cutting and depaneling of circuit boards, where we use an ablation process. It's like a chainsaw and a paring knife; they can both cut things, but they have different designs for each specific purpose to be efficient in that field. Johnson: There's a lot of motion right now in materials. What challenges does that present to you? Schmidt: On the materials side, there are a bunch of new materials, but lasers are well-suited to manage them. Both the materials and dimensions are becoming extremely challenging. If you deal with pre-routed materials, for example, cutting out breakout tabs is becom- ing difficult when you have small devices or devices with a lot of sensors. More and more devices have sen- sors these days. You cannot use brute force to pry something out of a panel anymore; you have to use something that's a lot more gentle and doesn't leave a lot of side effects. Tolerances are extremely important as well because not adhering to a tolerance leads to not getting your small parts into small hous- ings. Today's PCBs have to be made to extreme standards that we couldn't even imagine 10 years ago. There's a lot happening on the mate- rials side, especially with RF and wireless com- munication. Again, lasers can deal with that well. We are addressing this through different lasers because not every laser can do every- thing, and they have different strengths and weaknesses. We can process different materi- als with different laser wavelengths and pulse length very carefully.