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Metal strain gauges need to be designed differently from strain gauges made from silicon. In this paper equations are derived that allow us to calculate the resistance change of metal strain gauges as a function of the position on a thick diaphragm, a thin membrane and a disc simply supported at the rim. The results of finite element calculations presented reveal that large deviations from these equations occur for strain gauges on thin membranes made of soft materials.

A normally-closed piezo-driven micro valve for gases and liquids has been developed. Due to the small deflection of piezo-actuated bending disks made of PZT a hydraulic transmission was constructed, which increases the displacement of the piezo disk up to the 25-fold. The switching times of the valve are shorter than 1.8 ms. Silicone gel serves as a transition medium in the hydraulic. It simplifies the manufacturing process and allows a flexible adaptation to different pressure requirements up to a differential pressure of 150 kPa switched with 300 V. Additionally, this silicone gel supports the sealing of the valve so it achieves an open-to-close ratio of 1:150,000 or higher. The overall dimensions of the valve are 13 mm ×13 mm ×3 mm , the dead volume is 0.33 μl, and the inner diameter of the valve seat is 200 μm. A transformer as small as the micro valve is able to produce driving voltages of up to 300 V with a response time of 2 ms. Therefore, the valve could be integrated into hand-held systems which are battery powered with 5–15 V.

A polymer valve with a small dead volume in the range of 6 nl and a response time faster than 1 ms is presented. The valve structure is simple and therefore easy to fabricate by injection molding or hot embossing. A layer of silicone rubber applied by a stamping technique not only promotes the sealing of the valve but also defines the gluing area during assembly. The fabrication is based on the AMANDA-process, which allows low-cost batch production of polymer micro devices.

We present a dosing system, which consists of four microvalves (presented by Rogge et al in the Proceedings of Eurosensors XVI, Prague, 2002, pp 109–110) for controlling and a movable membrane for flow measurement that divides a cavity into two chambers. The flow rate is determined from the straining of the membrane caused by the entering fluid. The displaced volume is detected by strain gauges integrated in the membrane. The overall dimensions of the membrane and the entire system are 2 mm and 10 × 50 × 6 mm3, respectively. A simple control was coded for dosing a certain amount of volume. This simple system has already achieved an accuracy of about 10%. The dosing system is manufactured with the AMANDA process, which allows for low-cost production of microcomponents from polymers.

A new manufacturing method has been used to produce a magnetically driven micro ball valve. The micro ball valve consists of three hot-embossed polymer layers and three metal layers. The layers are bonded with adhesive films which are microstructured by a punching process. The valve uses iron balls with a diameter of 3 mm as moving parts driven by a commercially available coil. The valve switches up to 200 kPa differential pressure with an initial current of 300 mA. The on–off switch frequency investigated was up to 30 Hz. In addition, the valve can operate as a proportional valve regulating the outlet pressure range from 0 to 112.5 kPa at an input pressure of 200 kPa. A switching time of 10 ms was measured.

We present a new method for the low-cost manufacture of micro fluidic devices from polymers for single use. Within a one-step or two-step process inside a hot embossing press, micro channels are thermoformed into a thin plastic film and welded on to a thicker plastic film or sheet. Sterile, hermetically sealed micro fluidic structures were fabricated from polystyrene for easy opening immediately before use. It even appears to be possible to produce micro fluidic analysis chips from polymers on a coil from which single devices are cut off for use.

A flow transducer for liquids and gases from polymer manufactured by the AMANDA-process has been developed. Outer dimensions of the transducer are just 5.5 × 4.5 × 1.2 mm3 (Fig.1). The transducer is based on the thermal anemometric principle and is operated in pulse-mode. A heater from gold or platinum enclosed in a 2.4 µm thick polyimide membrane is mounted in the center of a channel. Transducers with channels with different cross-sections have been tested to obtain a variety of flow ranges. The production costs of a transducer without electric and fluidic connectors can be less than 4 € (Euro) because the housings of the transducers are fabricated by hot embossing of polysulfone and most of the fabrication steps are performed in batches.

The market of chemical analysis calls for more sensitive devices which are able to analyze very small sample volumes of only a few nanoliters in a very short time. Therefore, devices are required, which contain components with microscopic dimensions. Such micro devices can be fabricated with the AMANDA process. This paper describes a microdegasser for high performance liquid chromatography (HPLC), which was developed in a cooperation of Agilent Technologies, Forschungszentrum Karlsruhe (Karlsruhe Research Center), and STEAG microParts and is manufactured now by STEAG microParts. The microdegasser is one of the components, which help the new generation of HPLC devices of Agilent Technologies to achieve their excellent market position.

Devices for mass separation have been engineered and were fabricated using the AMANDA process. The key component is a 5 micrometers thin, semi-permeable PTFE membrane with a circular diameter of 42 mm. The membrane is encapsulated in a PTFE and PEEK housing. In experiments, this novel device separated a gas flow of approximately 1 (mu) l/min from a methanol feed stream of 1 ml/min at a pressure difference of 900 hPa. The separation process was simulated in FE- calculations exploiting analogies between diffusion theory and heat transfer. Mechanical stability and creeping of the PTFE membrane were investigated as well. All parts in contact with the fluids to be separated are made of chemically inert polymers. As a consequence, a welding process had to be developed for bonding the PTFE membrane to the PTFE housing. This was accomplished with an intermediate FEP layer. Extension of this bonding technique to other AMANDA products will facilitate fabrication of chemically inert micropumps, valves, and sensors.