Micromachined Parts Advance Medicine, Astrophysics, and More This 532-nanometer NASA Technology laser system is used for micromachining metal Anyone who remembers the Micro Machines line and silicon wafers. of toys might be surprised to learn that the tiny model vehicles are positively gargantuan com- pared with actual micromachine manufacturing. While specimens of the miniature toy collection may indeed have been “smaller than a silver dollar,” some industrial micromachined parts compare similarly to the breadth of a human hair, which is around 75 microns. For example, Potomac Photonics, a Baltimore-based company, might use a high-speed laser to drill a grid of 25,000 holes, each less than two microns across, through a steel surface with an accuracy of plus or minus 0.3 microns—and do it cheaply enough that the part can be considered disposable. “That’s pushing the limits in terms of machining capability,” says Mike Adelstein, the company’s president and CEO. The company’s website is rife with photos in which looming pennies and dimes dwarf the intricate metal gears, microfluidic channels, and 3D-printed plastic parts it has produced. Since its founding in 1982, the company has worked on a number of Small Business Innovation Research (SBIR) contracts with the Department of Defense, the National Science Foundation, and other agencies to displays, and information storage. At the time, however, “NASA certainly was interested, because they do a lot develop technologies such as lasers and ultrasensitive making these small-scale elements was time-consuming of work with lasers and light,” Adelstein says. detectors. However, Adelstein says it was a set of SBIR and hugely expensive. The work that Potomac Photonics carried out under contracts with NASA’s Marshall Space Flight Center in While near-infrared lasers were commonly used to NASA SBIRs ended up being a major breakthrough for the mid-1990s that was especially influential in putting manufacture metal components, less was known about the company, resulting in a workstation that allowed the the company on the cutting edge of micromachining, the use of excimer lasers, which operate in the deep ultra- user to custom-design diffractive optical elements and leading to the work it does today. violet range, to shape polymer and glass elements, such as produce them cheaply and efficiently (Spinoff 1998). There were two objectives to the Phase I and II SBIR lenses, Adelstein says. But the work proved the ultraviolet Technology Transfer contracts awarded to the company. One was to prove the lasers were effective on these materials. capability of excimer lasers in crafting intricate, diffractive Then, the company wanted to develop an integrated, Although its work with NASA was geared toward optical elements—lenses etched with thin, micro-struc- computerized workstation capable of mass-producing manufacturing diffractive optics, the company found that ture patterns that manipulate the light passing through such optical components, using AutoCAD software to the digital fabrication technology it had developed for the them. These are used in a wide variety of applications, digitally control the process and make it faster, more workstation was useful in all sorts of micromachining. from sensors and monitoring equipment to fiber optics, flexible, and cheaper. And micromachining is, in fact, one common application 142 Industrial Productivity Spinoff 2015 “The work with NASA showed a different way these of making components and pushed the limits technology of the . set tone It really the our direction for in field.” leading this — Mike Adelstein, Potomac Photonics Here, a grid of tiny holes has been drilled in stainless steel. Potomac Photonics can accurately place and drill holes as small as one micron, or a thousandth of a millimeter. Spinoff 2015 Industrial Productivity 143 of the very diffractive lenses the workstations could now Benefits cheaply produce. These lenses allow optimized, precise Potomac Photonics continues to work often with laser cutting, drilling, and ablation—whereby a con- NASA as a supplier of parts and services. In the spring of trolled amount of material is vaporized. 2014, the Center for Research and Exploration in Space “It was that breakthrough that led to everything we do Science and Technology (CRESST), formed by NASA, now,” Adelstein says of the work with NASA. “It showed contracted the company to have laser markings inscribed a different way of making these components and pushed on filter carriers for imaging systems on the ASTRO-H the limits of the technology. It really set the tone for our satellite being developed by the Japan Aerospace direction in leading this field.” Exploration Agency, with participation from NASA and Over the years, he says, the company grew a contract other space agencies. manufacturing business, making tiny parts to order with “We needed some precision reference marks for quick turnaround times. Around 2008, the workstations which their laser system worked well,” says Meng Chiao, were discontinued, and the company now focuses on a research scientist with the University of Maryland “rapid contract micromanufacturing,” as Adelstein puts Baltimore County, one of the institutions that comprise it, as well as continuing to develop new technologies to CRESST. that end. The work ranges from microhole drilling and The satellite, scheduled for launch in 2015, will look precise laser marking to hot embossing and 3D printing, for clues to the origins of the universe using several dif- This example demonstrates the company’s ability to laser working with metal, plastics, glass, ceramics, and silicon. micromachine polyethylene terephthalate, a thermoplastic ferent imaging systems to observe X-ray and gamma ray Popular applications include medical devices, biotechnol- polymer, at micron scale. activity around black holes and supernova remnants. To ogy manufacturing, and electronics, among others. get a clear picture, the various telescopes and imagers Software and laser technology have come a long way Since its SBIRs with NASA, Adelstein says, the com- must be precisely aligned, and the detector assembly team since the mid-1990s, and Adelstein says, in the company’s pany has grown by 50 to 75 percent. The staff has grown decided to accomplish this by putting reference marks on production line and in the world of modern technology, from about half a dozen to 20, and revenues for 2014 the rings of gold-plated aluminum that hold filters in the “everything’s gotten smaller, and everything’s gotten were projected at around $3.2 million. different instruments’ aperture assemblies. The marks can more precise.” Another frequent client these days is Johns Hopkins then be visually aligned, but they have to be placed with Medicine, and around the time of the ASTRO-H project, exact accuracy, as the slightest discrepancy would begin Potomac Photonics returned to its roots to supply the to take on a magnitude of light years as the imagers look organization with a diffractive optic lens. Also around this deeper into space. time, the company used its hyper-accurate 3D printer to Chiao, who works closely with the X-ray calorimeter produce a device designed to fight cervical cancer in the group in the Astrophysics Science Division at Goddard developing world for Jhpiego and Momo Scientific, two Space Flight Center, says Potomac Photonics came rec- companies working with Johns Hopkins University. ommended to her by a colleague. “To my knowledge, Another recent medical project Adelstein takes pride they’re the only company with this laser marking system in is the production of sutures with tiny wells in them, and with precision placement capability,” she says. in which radiation can be embedded for localized cancer The company was able to turn the work around in less treatment. His wife still suffers from health issues due to than 24 hours. radiation treatment she received for Hodgkin’s disease when she was a teenager, as do many who are subjected to massive doses of radiation in attempts to fight cancer, he says. These sutures allow a much safer alternative, at least Here, silver nanoparticle for treatment of prostate and breast cancer. conductive lines are “The ability to machine parts like this that are so embedded in Kapton tubing for use in a medical device. small—it’s going to be life-changing,” Adelstein says. v 144 Industrial Productivity Spinoff 2015 Not limited to lasers, Potomac Photonics also fabricates tiny, plastic parts with a high-precision 3D printer. These molds the company made for Johns Hopkins University were used to make high-aspect ratio wells in a polymer material. Spinoff 2015 Industrial Productivity 145