Originally Published EMDM October 2005
Product Update
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Focus on suppliers of micro- and nanotechnology products
Micropumps weighing only 0.8 g feature liquid flow rates between 50 nl/min and 5 ml/min. Gases can be pumped at rates between 50 nl/min and 15 ml/min. Until recently, these pumps were available only as prototypes. Bartels Mikrotechnik GmbH (Dortmund, Germany) has developed a process that allows their production for high-volume applications. They are suited for use in portable insulin injection systems, implantable artificial sphincter systems, and numerous other medical devices.Moulded from polyphenolsulphone, the pumps are powered by a piezo-based device that operates between two double valves. The design’s simplicity, says project manager Ron Meyknecht, is a key attribute of the product. Production and assembly techniques are straightforward, and the use of injection moulding renders mass production of the micropumps cost-effective, he notes.Suitable for stand-alone applications, the pumps can also be integrated into custom systems, such as lab-on-a-chip products. Various electronic controls, including some that can be operated from a PC, are available for testing purposes.
Piezo Technologies
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Piezoelectric ceramic components reportedly enable size reductions and improved performance in medical imaging, diagnostic, and therapeutic devices. One recent development involves the use of piezoceramic technology to produce miniature fans. The components are offered by PiezoFans, a subsidiary of Piezo Technologies. Both firms are based in Indianapolis, IN, USA.The piezo fan cooling system comprises a flexible blade attached to a ceramic element. Minimal power is required to set the blade in motion. The system requires very little space and consumes less power than conventional fans, according to the firm, yet it offers satisfactory cooling. The company’s proprietary ceramics and their performance capabilities have enabled the development of this technology, according to the firm. Piezo Technologies develops and produces piezoelectric materials as well as composites, transducers, arrays, and systems used in microtechnology applications. Custom products are a specialty.
Boehringer Ingelheim microParts GmbH
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Injection-moulded microspectrometers enable the design of compact, dedicated, inexpensive analyzers. Developed by Boehringer Ingelheim microParts GmbH (Dortmund, Germany), the devices have applications in blood diagnostics, in-line processing, material identification, and colour measurement. Dermatology applications are currently under development as well.The UV/visible-light and near-infrared microspectrometers are fabricated from a polymer that protects the devices from shock and vibration. They can also withstand temperature variations up to 100 K. All functional elements are contained within a single moulded part, eliminating the need for alignment and assembly of the constituent parts and recalibration in the field.The products are available as OEM modules and PC-based systems, and they include a light source. The firm provides system implementation and custom product development services.
MPS Micro Precision Systems AG
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A firm with more than 70 years of experience producing small parts to submicron tolerances in industrial quantities routinely develops, manufactures, and assembles miniature medical devices and implantable drug-delivery systems. MPS Micro Precision Systems AG (Biel-Bienne, Switzerland) is currently overseeing several leading-edge medical technology projects at its facility.One such project involves the production of an implantable ophthalmic drug-release system. The all-titanium assembly includes an actuator, springs, planetary gears, and four-point contact bearings. The components are housed in a package measuring less than 1 cm3. The company developed a production process to assemble the device in large quantities.The firm is also currently overseeing the serial production, cleanroom assembly, and validation of an all-titanium implantable peristaltic pump head with a 4-mm-diam bearing (pictured). It is also involved in the manufacture of a fully automated positioning-assistance device for spinal surgery procedures. The instrument has successfully completed clinical trials in eight hospitals worldwide.The company places a priority on manufacturability at the outset of every project. Manufacturing and process capability studies and statistical validation procedures ensure a CpK of 1.33.
ThinXXS GmbH
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Barely larger than a coin and lighter than a pencil, a self-priming diaphragm pump achieves liquid flow rates up to 6 ml/min. Miniature components such as this pump will make possible the development of next-generation mobile IVD devices, according to thinXXS GmbH (Zweibrücken, Germany), to replace the bulky equipment that is currently used in hospitals and clinics.The MDP1304 micropump comprises four components: a pump head, two check valves, and an actuator. Designed for OEM use, the parts can be modified to achieve customer-specified performance parameters. The modular concept enables flow rates, back pressure, and pump dimensions to be easily customized.
The actuator driving the pump is made of a piezoceramic material in lieu of a dc motor. Its power consumption is rated at less than 0.2 W.
Aerotech
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A fully integrated motion system couples automated material handling with direct-drive linear and rotary motion capabilities. The system can increase throughput in the manufacture of stents compared with traditional manufacturing techniques, according to Aerotech (Aldermaston, Berks, UK).The VascuLathe’s integral linear and rotary design reportedly boosts throughput two to five times compared with screw-based and related manufacturing processes, while maintaining submicron tolerances on complex part geometries.
Kern Micro- und Feinwerktechnik GmbH & Co. KG
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High-precision machining systems achieve ±0.3-µm positioning accuracy, specified by VDI/DGQ 34441. Accuracy is guaranteed along the entire x-y 500-mm travel. The Pyramid-Nano product line was recently introduced by Kern Micro- und Feinwerktechnik GmbH & Co. KG (Murnau, Germany). It represents a new benchmark for the firm, whose other high-precision machining centres guarantee 2.5-µm workpiece accuracy, according to managing director Burkhard Rother.The machines have integral hydrostatic drives and guidings. During the development phase, the firm tested alternative linear drives, says Rother, but decided against them to prevent cogging. Hydrostatic systems are more expensive than linear drives, but the extra cost is absorbed by the savings in electricity, he explains.The machine body is made of Kern-Armorit, a polymer-concrete material, and is reinforced by steel bars. The material and unique construction design ensure vibration-free operation. All heat-producing devices are located outside the machining centre. The machines were designed with a cooling system that maintains a constant temperature where all of the critical parts are housed.Two spindles are available: one spindle achieves 500–50,000 rpm at 6.4 kW; the second one operates at 200–36,000 rpm at 11 kW. ATC capacity can be extended to 96/75 pockets without altering the machine’s external dimensions. An automatic workpiece changer with 20 pockets is standard.
maxon motor AG
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A company’s line of microdrive products includes brush and brushless dc motors in diameters between 6 and 10 mm. Designed with ironless winding technology, the motors are characterized by an absence of magnetic detent, minimal inertia and electromagnetic interference levels, low inductance, and high efficiency. The products are available through maxon motor AG (Sachseln, Switzerland).The RE 8, with a 0.5-W assigned power rating, and RE 6 (0.3-W) models feature 0.8-mm-diam ceramic shafts and external diameters of 8 mm. A 6-mm-diam motor with a 1.2-W assigned power rating is also available.The cylindrical brushless EC motors feature electronic commutation. The only factors affecting service life are the bearings. Free of detent, the motor reaches high speeds even at low voltages. The winding system can be constructed to suit specific applications.Brushless dc external motors, also known as flat motors, come in two types. The EC 6 measures 6 mm long and 2.2 mm diam, while the EC 10 is sized at 10 mm long and 2.52 mm diam.
Leister Process Technologies
Compact mass-flow sensors that accurately and rapidly measure gas flow in the sub-liter-per-minute range are available in three styles for OEM use. The MFlow 200 sensors are offered by Leister Process Technologies (Sarnen, Switzerland).All of the sensors are individually calibrated and temperature compensated, and they provide a linear analogue 0–5-V output signal. Synchronous and asynchronous digital output interfaces are also included. Various housings and tubing connectors are available.The silicon chip is micromachined at the company’s in-house fabrication facility to ensure utmost quality control. Final qualification tests have been completed, and the product is now available for OEM use worldwide.
Hermetic Switch Inc.
Suited for use in hearing aids, surgical instruments, pacemakers, and other implantable devices, a magnetically operated reed switch measures a mere 4.06 mm long, 1.22 mm wide, and 0.89 mm high. Hermetic Switch Inc. (Chickasha, OK, USA) claims it is the smallest switch of its kind on the market.The switch requires no electric power to operate and combines switching and sensing functions in a single package. The hermetically sealed contacts are insensitive to electrostatic discharge. The leads can be custom configured for surface-mount or through-hole designs. Sensitivity ranges between 2 and 15 ampere-turns are available.Technical specifications of the device include 30-V maximum switching rates and 0.01 A in ac or dc mode, and 0.25-W power consumption.
Sensirion
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Third-generation MEMS-based liquid flow sensors are designed for integration into analytical and medical instruments as well as sundry life-science products. The chips can enable substantial cost, size, and weight reductions in finished products. The sensors were recently added to an existing line of liquid flow products from Sensirion (Zürich, Switzerland).A key design feature of the device involves embedding the sensing element with digital intelligence for linearization and temperature compensation. The liquid media are isolated within PEEK or fused-silica tubing. Mounted outside the flow path, the chip senses flow through the tubing wall.The largest model available from the firm can monitor flow rates up to 3 ml/min. Response time in all of the models are in the millisecond range. The flow sensors weigh a scant 6 g.
Fraunhofer Institute IFAM
A firm with several years of experience in metal injection moulding technology has developed a technique that enables the production of miniature parts from a range of metallic materials. The µ-MIM process enables the fabrication of metal parts with extremely small structures and complex geometries using conventional injection moulding techniques. This technology, says Fraunhofer Institut IFAM (Bremen, Germany), provides OEMs with design freedom, a vast choice of materials, and the ability to develop cost-effective series production processes.The µ-MIM process is typically used to manufacture microfluidic parts in various metals and alloys. Because various material combinations can be used, engineers can design in mechanical and physical properties such as thermal and electrical conductivity, resistivity, chemical resistance, and strength.Multifunctional microparts can be manufactured by means of two-component metal-powder injection moulding. Two metals with different properties are bonded during the moulding process, making it possible to integrate different functions in one structural element, which can result in cost savings.
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