direction every day,” said Donna Bibber, president and CEO of Micro Engineering Solutions (MES; Charlton City, MA), a manufacturer and developer of micro machined and micro molded parts.
Metrology, Part Handling Obstacles As micro components become smaller and more precise,
manufacturers face more difficulties in combining materials, which can be either metal or plastic pieces, to make an assem- bly, Bibber noted. Problems also can arise in measuring and testing sub-micron parts. “Te testing and the metrology is as important as anything,” she added. “You’ve probably heard the saying ‘You can’t make it if you can’t measure it.’ At this level of small, that is even more important.”
Additive Micro Process Combining aspects of 3-D printing and semiconductor
manufacturing techniques, Microfabrica Inc. (Van Nuys, CA) has developed an additive manufacturing process enabling the development of complex, sub-millimeter metal components and subassemblies. MICA Freeform, the company’s proprietary volume production process, can achieve 1 to 2-µm tolerances with 20-µm feature sizes, using a materials palette that includes nickel-cobalt, palladium, rhodium, and copper, covering a broad range of mechanical and electromechanical needs. “One of the most promising manufacturing technologies
as a whole is 3-D printing,” said Eric Miller, CEO of Micro- fabrica. “Today, the majority of 3-D printing is relegated to prototype development. However, with the advent of new processes and materials, production opportunities for 3-D printing are emerging. “Te constant and sometimes relentless drive to miniatur-
ization is pushing conventional micro-machining processes forward, and we see a lot of exciting things going on with laser machining and micro EDM, as they continue to be able to create more complex components and parts at a smaller and smaller scale,” Miller said. “Tat said, most of these subtractive processes struggle in the millimeter and sub-millimeter range, and many struggle with high-volume production.” Te MICA Freeform process combines aspects of both
3-D printing and semiconductor scale manufacturing. It’s an additive manufacturing process, allowing designers to achieve virtually any conceivable geometry, no matter how complex, Miller said. “Wafer-scale manufacturing principles allow us to achieve extreme precision, at the sub-millimeter scale, and leverage these attributes in a volume production process.” Microfabrica’s 40,000 ſt2
Endoscope measuring 5 mm in diameter by 20-mm long has 18 different metal components working together enabling moving and rotating a needle 360º.
A recent MES project involved making an endoscope
measuring 5 mm in diameter by 20-mm long in which there are 18 different metal components working together, so the endoscope can move and rotate a needle 360º, Bibber recalled. “You can imagine how much of a stack-up tolerance, literally microns, in this instance,” she said. “We can’t always scale up to the tolerance needed from machined parts to molded parts, but we have to plan for scale up from part one in terms of stack-up tolerances.” Another major issue is the trend toward more challenging
part geometries. “Te trends are small features, small parts, and small assemblies,” Bibber said. “Te challenges are mostly in handling, and metrology. Te bulk of the cost of the assem- blies are really in how you handle the components, and how they’re measured.”
42 Medical Manufacturing 2013 ) Van Nuys headquarters
includes its manufacturing fab and the company also has a medical device development office in Santa Clara, CA. “Addi- tive manufacturing in its simplest form is building in layers,” Miller said, “so we’ll take any designer’s 3-D CAD model and put it through our proprietary soſtware called Layerize, which separates the design into layers. Tis prepares the design for our fabrication process. We produce a photomask for each layer and then electrochemically deposit each structural layer until the entire device or component is built up on the wafer. Te last step is to chemically etch away the sacrificial material to resolve the design and release the component from the wafer.” Microfabrica works with industries requiring extreme
precision at a very small scale, Miller said, including aero- space/defense, semiconductor test, and medical devices. “For example, we fabricate a very complex metal composite for a micro-contact application in the semiconductor test industry,” he said, “and we’re working with a very large aerospace/de- fense contractor to develop a fuse for the military. We’re also engaged in developing a micro tissue removal device with a large medical manufacturer.”