Microtechnology Joins Mainstream at World's Largest Industrial Show

Originally Published MDDI June 2002

NEWS & ANALYSIS

Norbert Sparrow

Components that are typically measured in micrometers were big news at Hannover Fair this year. For the first time, microtechnology received equal billing with subcontracting, factory automation, logistics, surface treatment, energy, and R&D at the annual showcase for German and European industry.

Attracting approximately 7000 exhibitors and 250,000 visitors to the northern German city each April, Hannover Fair is arguably the largest trade show in the world. "We are now seeing the transfer of [microsystems] technology into marketable products," show organizers say. This carries considerable weight within the industry, and was greeted with enthusiasm by the almost 300 exhibitors in the microtechnology hall.

Previously, developers of microsystems and related supplies and services shared the R&D hall with university-based researchers and other "fuzzy-headed intellectuals," in the words of one exhibitor.

That environment became "too highbrow," says Rolf Slatter, managing director of Micromotion GmbH (Mainz, Germany). "There are enough real-life applications out there now to prove the viability of microtechnology," Slatter says. Although automotive and electronics represent the largest markets for microtechnology, it also has had an appreciable impact on the design and development of medical equipment. Numerous exhibitors stressed the existing or potential medical applications of their products, including one firm that premiered a tiny servo-actuator and another that had developed a tooling-free production process.

Micromotion GmbH caused a small sensation at the 2001 show when it introduced a miniature drive integrating what it describes as the world's smallest backlash-free gear. Building on this foundation, the firm returned to Hannover to present a miniature servo-actuator with a hollow center shaft. The Micro Harmonic Drive combines the drive and an electrically commutated brushless 1.2-W miniature motor, which was developed in partnership with Maxon Motor AG (Sachseln, Switzerland).

Attaining a repeatability of 10 arc seconds, the Micro Harmonic Drive is suited for a variety of positioning applications that require precise alignment or adjustment and backlash-free operation. Optical fibers, air or vacuum flow, or a laser beam can be passed through the component's 0.65-mm-diam hollow shaft. Applications include portable insulin and protein pumps and the precise adjustment of optical components on endoscopes, lasers, and microscopes, according to Slatter. "In the pumping applications, the actuator achieves very small and accurate steps to meter costly fluids in nanoliter quantities," he says. Because of its size and performance, the pump would be especially effective in implantable pumps currently under development, he adds.

Based in Duisburg, Germany, microTEC attended Hannover Fair to promote its tooling-free generative production method. The system can build 3-D microstructures by depositing thin layers of polymer materials on top of one another. Although the Rapid Micro Product Development (RMPD) process may sound familiar, its capabilities far surpass those usually associated with rapid prototyping techniques, according to project manager Helge Bohlmann.

While RMPD is certainly suitable for prototyping, more importantly it enables the tooling-free production of mass part quantities, he says. "We can split the laser beam, thus allowing parts to be produced in parallel," he says. "For some applications, we can produce up to 100,000 parts per hour." The technology is compatible with a range of light-curable materials that have functional properties, not just form and fit. "We are able to achieve a 1-µm resolution, and by adding postprocessing operations, we can attain nanoscale levels of roughness and near-optical quality," Bohlmann says.

One recent application involved the manufacture of a blood pump for a German OEM. "We developed the housing, inserted a die for the pressure sensor, and generated the interconnects in a single step," explains Bohlmann. "This one-step process replaced several manual assembly operations," he says.

The RMPD process also enabled the manufacture of an electrode holder, a honeycomb-shaped device with tiny holes through which electrodes are inserted to monitor neural activity. "The tolerances were extremely tight," says Bohlmann. The holes, measuring 150 µm diam, had to be sufficiently narrow to prevent the electrodes from slipping out, but not so tight as to inhibit their removal. "No other technology was able to hold these tolerances and achieve these results," says Bohlmann, "not even LIGA." (LIGA is an acronym for the German words for lithography, electroplating, and molding. The technology involves sending x-rays through a mask onto a PMMA resist, which is then used as a mold to produce metal parts by means of electroplating.)

Like Slatter, Bohlmann feels that microtechnology has earned its place within the mainstream of Hannover Fair. It's only fitting, he says, since the advent of new production methods that allow even small to midsized companies to benefit from microtechnology. "People used to ask me jokingly if the potential markets for microtechnology were any larger than the components themselves," says Bohlmann. If this year's show was any sign, Bohlmann will have the last laugh.

Hannover Fair returns to the Hannover fairgrounds April 7–12, 2003.

Copyright ©2002 Medical Device & Diagnostic Industry