Technology news
MOTION CONTROL COMPONENTS
Plastic Gears Offer Range of Reduction Ratios
Moulded gears achieve substantial reduction ratios while maintaining a high level of performance. Developed by Matthias Oechsler & Sohn GmbH & Co. (MOS; Ansbach, Germany), the low-weight Wave Drive gears attain reduction ratios ranging from 50:1 to 4800:1 in a single stage with minimal backlash. The components are suited for medical devices and laboratory equipment that require slow displacement or precise positioning.
"Traditional planetary and worm gears rely on several groups of engaged cogs to produce reduction ratios on that scale," says project manager Frank Pöhlau, "and each of those groups produces a certain amount of play. The inner gear mechanisms of Wave Drive components never have more than two stages, and so there is little in the way of backlash," he says.
Applications include certain types of laboratory equipment such as shakers and stirrers, according to Pöhlau. The gears may also find a use in intensive-care settings, he adds. "We have just looked at a nonmedical application that involves depressing a plunger into a cylinder in a continuous manner over a very long period of time—more than a year, as a matter of fact," says Pöhlau. "This has obvious potential for the administration of medication, for example." MOS is attuned to possible medical applications of its moulded components, he adds, because the company has extensive experience manufacturing asthma inhalation devices and other medical products under cleanroom conditions.
The gears are available in off-the-shelf sizes as well as in custom configurations. At the German subcontracting show Hannover Messe in March, MOS will introduce two new applications, according to Pöhlau. "One will be a 50-mm-diam gear with a reduction ratio of 1:50; the other is a gear with a 1:533 reduction ratio measuring about 30 mm diam," he says. "We think that these applications show a great deal of promise, and we plan to expand the range of gears in even smaller diameters and with other reduction ratios in the future," says Pöhlau.—Norbert Sparrow
Laser Welding Workstation Offers Plug-and-Play Design
Designed as a Class I device for a customer working with pacemaker and defibrillator leads, the BT-40W laser welding workstation has the footprint of a standard desk and is designed for use in cleanrooms, production lines, or application labs. The fully integrated system contains its own chiller, soot removal system, and gas manifold.
According to Ronald Lalli, president of Litron Inc. (Springfield, MA, USA), the system's appeal lies in its ease of use. "It's a totally integrated system on wheels. Just roll it in, plug it in, and away you go," he says. Once a program has been selected from the control panel, a worktable automatically presents itself for loading and unloading, minimizing the need to reach deep into the machine. Access doors are located on both ends of the laser workstation for maintenance and setup, or for part feeding in production-line environments.
An easy-to-use laser welding system is suited for applications such as batteries, leads, sensors, and other small components.
The BT-40W is based on a 40-W pulsed YAG laser from Trumpf Lasertechnik GmbH (Ditzingen, Germany), and can also be supplied without a laser, allowing manufacturers to incorporate an existing laser power source. The system includes the option of a rotary welding fixture and is outfitted with a four-axis controller that is designed to operate from either side of the workstation.
Lalli notes that the system's 40-W laser makes it more versatile than the average laser welding workstation. "If a more demanding application comes down the road," he says, "you know you can handle it."
A further advantage is the ability to change spot size while welding. "Operators are amazed at this feature," says Lalli, noting that spot size is programmable down to 300 µm. "This means that there's no subjectivity in setting the focus," he says. The system is virtually maintenance free and is expected to receive the CE marking this summer.—Benjamin Lichtman ELECTRONICS
Microsystems Supplier Develops Bidirectional Gas Flow Sensor
A company that specializes in the development and production of microsystems has introduced a bidirectional gas flow sensor. The component, which is suited for use with spirometers and related devices, can be optimized to suit a range of requirements, according to TMP (Enschede, Netherlands).
The sensor can measure flow rates from 0 to 5 m/sec at a full-scale resolution attaining 1%. Consequently, the device can detect high-volume gas and air-flows as well as low gas flow velocities. A Wheatstone bridge is used to detect movement of the heated gas. The sensor chips, which measure 2 X 1 X 0.5 mm, can be protected against humidity, contaminants, high temperatures, EMI, and vibration.
A gas flow sensor can detect high-volume gas and air flows as well as low gas flow velocities.
TMP has developed a number of other miniature components, including fluid systems, valves, capillary connectors coupled with on-chip sample injectors, and optical sensors.
The firm is a spin-off of the MESA Research Institute at the University of Enschede, considered to be a leading authority on microelectromechanical systems (MEMS). TMP maintains a close working relationship with the institute, according to marketing assistant Ronald van Holst, thereby ensuring access to recent developments in MEMS technology.
"MEMS is a disruptive technology," says van Holst. "It enables applications that simply weren't possible before, such as ink-jet nozzles." While MEMS has been around since the 1970s, the difficulties presented by etching hindered its growth, according to van Holst. "Many of the problems associated with MEMS have been resolved," he adds, "and it will experience exponential growth in the years ahead." The combination of expertise in MEMS technology and its production capabilities gives TMP a desirable profile for OEMs, says van Holst.
"We can take a project from the initial idea to final production of the microsystem," stresses van Holst. "Our partnership with OnStream, a microsystems fab that can produce up to 100,000 6-in. wafers a year, enables us to provide OEMs with low- to high-volume production runs. Beyond that, we offer a range of solutions from design to automated assembly and packaging," he adds. The breadth of available services within a multidisciplinary framework "is all part of what we call our seamless microsystem engineering approach," adds van Holst.—Norbert Sparrow
