Originally Published MPMN June 2008

PRODUCT UPDATE

Moving Beyond Miniaturization

Design innovation results in more-flexible and more-accurate electromechanical and electro-optical components

Stephanie Steward

Make it smaller. Add more functions. Keep it cost-effective. These common demands keep the device industry constantly moving forward, requiring manufacturers to improve the capabilities of their components to meet the requirements of OEMs. Electromechanical and electro-optical components are no exception. Having spent years focused on reducing the size of such components, manufacturers are now giving more attention to improving aesthetics and power consumption efficiency, increasing the capabilities of their components, and simplifying component integration. These efforts reflect the industry’s need to make components smarter, not just smaller.

Motion Control Gains Momentum

Because technology has steadily improved in recent years, motion control experts are being challenged to increase the functionality and flexibility of their components. One company that has benefited from the industry’s constant innovation is New Scale Technologies (Victor, NY; www.newscaletech.com), which manufactures small motion systems based on ultrasonic linear motors.

“As the engineers were pushing to reduce size, they tried a number of design variations and improvements to get there,” says Dan Viggiano III, vice president and general manager of New Scale’s OEM and industrial business unit. “Our first motors used a piezoelectric tube and a cylindrical nut, which later evolved to four separate piezoelectric plates bonded to a rectangular nut,” he recalls. “Among other advantages, the plates are easier to make smaller.”

In addition to reducing the size of its motors, New Scale is moving toward integrating position feedback and drive chips into its modules to increase their value and utility for product designers. It’s also exploring new applications for its SQL-M microactuator, such as using it as an electronic access control.

Incorporating new features into motion control components can be a complicated process requiring cost-effective design strategies. “As more end products become smaller, portable, and operate longer, their physical aspects and overall power consumption become more viable concerns,” says Karl Meier, marketing manager, Advanced Motion Controls (Camarillo, CA; www.a-m-c.com). Servo drives and drive systems are required to comply with regulations imposed by FDA, the European Union, and other agencies. These standards go beyond those required to meet UL and CE requirements for general industrial equipment, which mainly focus on device safety compliance, according to Meier. In fact, Meier says, in terms of keeping to allowable levels of EMI radiation, compliance with EN 55011 is more difficult to achieve than compliance with the latest electromagnetic compatibility CE directive, 2004/108/EC.

Advanced Motion Controls has considered these requirements in the design of its servo drives so that OEMs don’t have to. “There is an increase in demand from medical equipment design engineers to merge their control system designs more synergistically with the drive electronics,” Meier says. By implementing certain criteria into its drives, Advanced Motion Controls has reduced the need for external considerations and simplified the overall integration of the servo drives into medical equipment. The drives include compact PCB-integrated flat-wire inductors for motor outputs and power inputs, common-mode filtering on logic supply input, and PCB inter- and intralayer layout techniques.

By tightly integrating similar components, the size, weight, and number of PCBs are reduced even further, according to Meier. “This trend toward nonstandard products allows for completely optimized designs that are a much less expensive solution, yet [they are] fully functional in every way,” he says.

Thermal Components Get a Makeover

Thermal components such as heaters and circuit breakers are also subject to the standard industry demand to reduce part size. However, efforts to improve the aesthetics and functionality of these components in ways that ultimately benefit the patient have been increasing.

“The specific trend we are following is the continued effort of device manufacturers to focus on patient comfort in the healthcare setting,” says Richard Hartfelder, global industry market leader for Watlow (St. Louis; www.watlow.com). “The trend has been to shorten or eliminate the hospital stay of patients through improved treatment and surgical techniques, [hence] the development of more-accurate medical diagnostics, imaging capabilities, etc.,” says Hartfelder. “[This] is where the need for smaller-sized heaters and heaters that can be configured to match application requirements come into play.”

The problem, Hartfelder says, is that most equipment developers frequently underestimate the complexity of integrating a thermal component into their medical devices. This can cause massive manufacturing headaches later in the development process. To reduce product size and complexity while also improving performance, Watlow created its Ultramic ceramic heater, which is compact and provides high temperature ramp rates for use in heating small devices. “The Ultramic, due to its ultralow current leakage, also has allowed manufacturers of ac-driven equipment to eliminate dc power supplies and circuits used to drive dc-rated electric heaters,” Hartfelder says.

Also constantly striving to reduce part size and increase electrical performance, Schurter Inc. (Santa Rosa, CA; www.schurterinc.com) offers single-, three-pole, and rocker-actuated circuit breakers for medical equipment. The company has been approached to create a circuit breaker that can accommodate automatic or robotic assembly processes. But Marjorie Tibbs, marketing communications coordinator for Schurter, has noticed a trend toward focusing on the quality of the finishing of a thermal component. Aesthetics of the design and form of the component are gaining importance, though they’re still a slightly lower priority than electrical performance. Tibbs says Schurter is responding by offering its products in a range of popular colors—customers are requesting the illuminated rocker in blue—and modern shapes and symbols.

Flexing Electro-optics

Electro-optical components include products such as fiber-optic light guides, hybrid fiber-optic interconnects, lasers, and laser diodes. Advances in laser technology and increases in the flexibility of many optical-fiber-based scopes make it critical that such fibers be able to handle higher energy at extreme bends. To address this need, OFS, Specialty Photonics Div. (Fairfield, NJ; www.specialtyphotonics.com) has created its HCXtreme optical fibers for transmitting laser light. The fibers were developed to be used with high-power laser systems for the treatment of benign prostate hyperplasia and laser lithotripsy. Designed for delivering high-power laser light under the tight bend conditions of medical diagnostic applications, the fibers are coated with a fluoroacrylate coating, which has a lower refractive index than that of silica. This refractive index allows the coating to also act as a light-guiding second cladding.

Damaged fibers and scopes had previously been the result of continued increases in laser energy that caused the fibers to bend as the scopes were used to treat hard-to-reach areas in the human body. Compared with standard fibers, HCXtreme fibers demonstrate the ability to handle higher powers while being subjected to increased bends. “The results were dramatic as bend diameter went from 23 to 5 mm at 100 W Ho:YAG,” says Dominic Speciale, market manager.

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