cessing applications for the TruMicro 5000 line include cutting, structuring, ablation and drilling. “That’s a short pulse, actually high intensity, because in the peak of the pulse, you’ve got the power of multiple tens of megawatts,” Weiler observes. “It’s like a very tiny, but powerful hammer. And you’ve got like 800,000 of those hammers a second. This is how it works, this is how you get the productivity.” The Trumpf TruMicro 5000 line comes not only in different wavelengths, but also different power levels, adds Weiler, not- ing that the TruMicro 5250 green picosecond laser is the best bet for this type of medical work. Trumpf, which launched its first picosecond lasers in early 2008, is now offering its second-generation picosecond lasers for microprocessing ap- plications. “I’d say for the cutting nonmetals in medical, truly it’s an enabling technology. You couldn’t do that before, with this kind of quality.
“At the beginning, it was a testing element—no one was sure it was going to take off,” Weiler recalls of picosecond la-
sers. The technology is used not only in medical, but for a wide variety of applications, he adds, including semiconductors. Key to the success of these short-pulse lasers is the quality of the cut. “If the quality isn’t there, it means it must be somehow post-processed, and believe it or not, it’s done manually. There are guys sitting there with a microscope and checking if they see anything on the stent, and then they do sandblasting or brushing, and check again. And it is very time-consuming and a lot of labor.”
Hand finishing of stents involves small sandblaster tools used with microscopes to spot any imperfections in the stent, he notes. “Camera vision is literally impossible to implement. The human eye, you can teach it. You have to somehow hold the stent under the microscope and play with it, and then you see the obstacles. You can do it manually, but it’s very difficult, and a lot of stents are made out of Nitinol, which is 50% nickel and 50% titanium, the shape-memory alloy. It’s a very expen- sive material, and you waste a lot of money.”