An MD&DI September 1998 Column
"Laser micromachining is a cutting-edge technology in more ways than one," jokes C. Paul Christensen, PhD, chief technical officer of Potomac Photonics, Inc. (Lanham, MD). He adds, more seriously, "As manufacturers try to make devices smaller, the conventional mechanical methods don't work any more. Engineers need new tools for making very small articles."
Christensen describes how lasers can be used to machine miniature device components. He compares the laser process to mechanical machining and describes differences in speed and cost.
Paul Christensen deals with the little picture.
"Micromachining is increasingly becoming part of medical device production, where it has a real impact on the health industry," Christensen says. "It's important for engineers and manufacturers to understand micromachining and develop a vision for how they can take their product to a smaller scale."
Christensen has been involved with lasers or laser applications throughout his professional career. In 1968, he earned his MS in electrical engineering from the Massachusetts Institute of Technology (MIT; Cambridge), where he worked on a laser-related project as part of his master's thesis. After graduating from MIT, Christensen worked for Hewlett-Packard (Palo Alto, CA) for several years on microwave projects. In 1973, he earned his PhD in electrical engineering from the University of California, Berkeley, and took a research position at the University of Southern California (USC; Los Angeles), working for six years with the faculty on laser development and applications.
In 1979, Christensen took leave from USC to go to Washington, DC, to run a program, "Quantum Electronics, Waves, and Beams," at the National Science Foundation (NSF). "It was meant to be a temporary position, but I found I liked the work and I wanted to move in a different direction than academic research was taking me," he recounts.
When the NSF program ended, Christensen spent a year with the consulting group BDM International, still working on laser applications. Then, in 1982, he established Potomac Photonics, Inc.
"For a long time I was president of the company," Christensen explains, "but that was taking me into more of an administrative area." A man who enjoys the engineering side of the job, Christensen was pleased when, in 1997, the company found someone else to handle the administrative side of the company. "I gave up the presidency and became the chief technical officer," he explains. "I do more hands-on work now, technical work and project management. I like the practical work and the practical applications."
One of the advantages to working with lasers, Christensen believes, is their versatility. "Laser micromachining is applicable to a wide range of materials. It's not just applicable to metal, or plastics, or ceramics; to flat sheets or round tubes. It's applicable to all of them."
Current challenges in the laser micromachining field include developing ways to make devices and components smaller while constantly improving production efficiency and economy.
"The issue is one of education," he says. "Most people don't get the experience of using a laser to fabricate something in the normal course of their life experience. They don't use lasers in shop in high school. So there's a need to work around this barrier, this lack of an intuitive feel for the experience. There's a need for engineers to experience new approaches to manufacturing small components.
"I'm pleased that the most exciting times for laser micromachining are not in the past, but in the present," Christensen says with satisfaction. "Not everybody can say that about their field."
Dru Pagliassotti is a senior associate editor at MD&DI.