Systems: Novel Product and Process Designs

A New Concept for an Absolutely Encoded Angular Resolver

V. Mayer, T. Botzelmann, K.-P. Fritz, J. Seybold, H. Kück
Hahn-Schickard-Gesellschaft, Institute of Micro Assembly Technology, Allmandring 9b, 70569 Stuttgart, Germany

Abstract

At HSG-IMAT a new concept for an absolutely encoded optical angular resolver has been developed. The key element of the sensor concept is a disc with a high precision solid measure which is fabricated using the well known manufacturing process for compact discs (CD-Technology). Using this process, it is possible to fabricate a high precision solid measure in high quantities and at low manufacturing costs. To detect the absolute angular position, a laser beam is focused onto the solid measure. The beam is deflected by the diffractive gratings of the solid measure, whereupon the different first orders fall onto separated elements of a photo diode array. To verify the principle of operation an experimental setup assembled under a microscope, with a CCD-chip instead of a photodiode array, was used to demonstrate the signal modulation. Based on these experiments, a small size demonstrator device was designed and assembled. The successful experimental results with this demonstrator device show the large potential of this new sensor concept for different applications.

Keywords: angular resolver, rotary encoder, optical sensor, absolutely encoded, low cost, compact disc, laser

Design and Optimization of Flat Solenoid MEMS Actuator by Selection of Proper Material Properties

G. Todorov, K. Kamberov, and L. Dimitrov
CAD/CAM/CAE Laboratory, Technical University of Sofia, Sofia 1000, Bulgaria

Abstract

MEMS actuators are widely used in modern industry. Their main advantage is the concentration of desired mechanical characteristics in a limited space. This paper presents a design and optimization of a flat solid MEMS actuator. The optimization is based of the selection of material properties needed for the achievement of the actuator mechanical characteristics required for good performance. The main goal is to reach necessary output mechanical force with minimal side force effects. The output mechanical force is evaluated by modeling and simulation of the magnetic field and its parameters by the use of FE Analyses. In order to make proper simulations, a finite element model of the complete actuator structure is made up suggested).

Another problem that has been solved in the paper is checking of actuator’s geometry and its dimensions in order to evaluate the effective use of the material. As a result of the study, the optimal output function of the mechanical force versus the stage position has been determined. This has been done on the basis of updated material specifications. The optimal design of a flat solenoid MEMS actuator is proposed.

Keywords: mini actuator, magnetic field, FEA, MEMS

Polymer Lab-on-Chip Systems with Integrated Electrochemical Pumps suitable for Large Scale Fabrication

J. Nestler(a), A. Morschhauser(a), K. Hiller(a), T. Otto(b), S. Bigot(c), T. Gessner(a)(b)
a: Center for Microtechnologies (ZfM), Chemnitz University of Technology, Chemnitz, Germany
b: Dept. Multi Device Integration, Fraunhofer IZM, Chemnitz, Germany
c: Manufacturing Engineering Centre, Cardiff University, Cardiff, UK

Abstract

A low-cost, polymer based microfluidic platform is described which not only includes passive microfluidic parts, but also pumps based on an on-chip electrochemical gas generation by electrolysis. A hydrogel is used as electrolyte material, which allows a simple fabrication process by screen printing or stencil printing. Test structures were designed and fabricated to illustrate the feasibility of the approach for batch processing. Microfluidic chips including reservoirs and channel structures were fabricated by micro injection moulding and used to demonstrate the movement of liquids inside micro channels by the proposed micro pumps.

Keywords: micro pump, electrolysis, hydrogel, polymer, microfluidics, lab on chip, point of care

New Technology for Setting Up the Working Coordinate System in Micromilling

K. Popov(a), S. Dimov(a), A. Ivanov(a), D. T. Pham(a), E. Gandarias(b)
a: Manufacturing Engineering Centre, Cardiff University, Cardiff CF24 3AA, UK
b: Mondragon Goi Eskola Politeknikoa, Mondragon Unibertsitatea, Loramendi 4, 20500 Arrasate, Spain

Abstract

A major issue in micro milling is the setting up of the origins of the Machine Working Coordinate Systems (MWCS). The existing methods for carrying out this operation have an unacceptably high error along the Z axis, due to the spindle thermal enlargement, and are effective only when the machining is “relative” to other surfaces milled with one cutting tool within one operation. Therefore, more efficient technical solutions are required for setting up MWCS and to reduce further uncertainties associated with micro-milling operations.

This paper describes a new cost-effective method for setting up MWCS that applies a new technical solution for detecting the contact between the cutting tool and the workpiece. A prototype system was used to validate experimentally the accuracy and repeatability of the proposed method. The results obtained showed that the sensitivity of the system is sufficient to detect accurately the contact between the cutting tool and the workpiece, and thus to set up the MWCS origins. It was concluded that by applying this method it would be possible to minimise uncertainties introduced by the spindle thermal enlargement and touch probe run-outs in setting up micro machining operations. Also, the tests undertaken showed that the prototype system is reliable and convenient for use by machine operators.

Keywords: micro-milling, on-line measuring systems, tool–workpiece coordinate system setting

Development of a Dynamic High Precision Miniature Milling Machine

C. Brecher(a)(b), R. Klar(b), C. Wenzel(b)
a: Werkzeugmaschinenlabor (WZL), RWTH Aachen University, Aachen, Germany
b: Fraunhofer-Institute for Production Technology, Aachen, Germany

Abstract

One of the main focuses in many research fields is the miniaturisation of work pieces and components. Micro fluidic, micro mechanic, micro electronic and micro optical functional groups are integrated into smallest space to microsystems for medical, information technology or automotive purposes. Directly opposed to the miniaturisation trend of these products are the machine tools used for the production becoming bigger and bigger, with the result that the proportion between the machining space and the needed floor space is more and more inefficient. To meet the process requirements as well as the requirements of the machine users of flexible and small high performance machine tools the Fraunhofer IPT developed and designed a compact high precision milling machine. The paper describes current trends in the field of compact machine tools under special consideration of the mechanical setup and the development of a small and high precise as well as high dynamic micro milling machine.

Keywords: compact machine tool, high precision, mould and die making

Photosensor of CDSSE for Fiber Optics Applications

Peter Shindov(a), Nasko Elektronov(b),Valery Serbezov(c), Franz Herbst(c)
a: Technical College-"John Atanasoff"
b: JN-Corp.
c: Multicoats Ltd.

Abstract

The development of new generations of laser source for fiber optic’s applications require more fast new photosensors with spectral characteristics in visible range. The idea of this work is development of technology and device – fast photosensor with spectral range adapted to modern lasers for the quickly increasing needs of optoelectronics and fiber optics communications. By pulsed laser deposition (PLD) usage UV N2 Laser for ablation λ=337.1 nm, energy per pulse 8 mJ and CW 60 W CO2 Laser for heating are produced thin CdSxSe1-x films on quartz substrate. Polycrystalline thin films with thickness from 0.5 to 2.0 μm and dominant orientation – (002) are formed by energy density 4.5 J/cm2 and repetition rate 20 Hz .The thin films are investigated by EDAX and SEM. The films are additional thermo treatment for increasing ratio photocurrent – dark current. This ratio reaches 107. By means of TEA UV N2 Laser with energy per pulse-0.3 mJ, pulse duration 2 ns are formed planar Ohm contacts from CdO directly onto thin film. The contacts are investigated by XRD. By means of coordinate table the contacts are formed on the backside of the structure. The dimension of photosensitive structure is 250x250 μm. The distance between contacts areas is 10 μm. The spectral response of devices is measured. The maximum spectral sensitive is at λ=575 nm. Lux ampere characteristics are measured. The increasable fronts and decreаsаble fronts at the structure are measured. They are 2 ns, at ratio 1000.

Keywords: Fast photosensor, visible range, PLD, planar Ohm contacts, EDAX, SEM, XRD.

Thin Film Polymer Actuators for Micro-Fluid Applications

A. Boersma, R. de Zwart, R. Boot, P.J. Bolt
TNO Science and Industry, Eindhoven, The Netherlands

Abstract

Thin film actuators have been manufactured for application in small devices, such as valves and (micro)pump. These actuators are based on new materials especially suited to be used as electro-active dielectric elastomers. The properties of these elastomers are tuned to the specific requirements. It was found that the electric voltage required for operating could be lowered by a factor of three to five. The thin film actuators were processed into small valves and pumps for the manipulation of gasses and liquids. It was shown that the actuators could be operated when immersed in a liquid (e.g. water) and can be used as valves in microfluidic sensor array devices. The next step in the development is fine-tuning of the valve setting in order to minimize leakage and optimize performance and durability.

Keywords: polymer, actuator, microfluidics

Automated Patch Clamping Systems Design using Novel Materials

R. Voicu, D. Esinenco, R. Müller, L. Eftime, C. Tibeica
S. Wilson(a)(b), A. Welle(c), E.Gottwald(c), A. Molleman(d), P.B.Kirby(b), W.Pfleging(e), J.J.Ramsden(b), M. Heckele(a)
a: Institute for Microstructure Technology, Forschungszentrum Karlsruhe, 76344 Eggenstein-Leo., Germany
b: School of Applied Sciences., Cranfield University, Cranfield, Beds. MK43 0AL, UK
c: Institute for Biological Interfaces, Forschungszentrum Karlsruhe, 76344 Eggenstein-Leo., Germany
d: School of Life Sciences, University of Hertfordshire, Hatfield, Herts.AL10 9AB, UK
e: Institute for Materials Research 1, Forschungszentrum Karlsruhe, 76344 Eggenstein-Leo., Germany

Abstract

Patch clamping is a highly sensitive technique used to measure the electrical activity of a cell. It is presently a low throughput cumbersome method which requires highly trained and skilled operators to obtain results of value. Patch Clamping is used in applications which include drug screening where there is demand for high throughput systems (HTS). While there are a few commercially available HTS patch clamping systems on the market using traditional patch clamping materials, there are no systems on the market using novel materials, or for dealing with cell networks – a physiologically important consideration for the developing fields of tissue engineering and understanding cell to cell interactions. This paper presents a summary of traditional patch clamping, mentions some commercially available high throughput patch clamping systems based on traditional materials then, using 4M technologies, introduces some novel materials and potential design approaches and processes for producing a polymer based automated patch clamping system.

Keywords: patch clamping, polymer microsystem, high throughput screening

New Approaches for an Automised Production in Ultraprecision Machining

C. Brecher, M. Weinzierl
Fraunhofer Institute for Production Technology IPT, Aachen, Germany

Abstract

Automation solutions are presented which ensure determinism and reproducibility for the handling and aligning of work pieces and tools in micro- and ultra precision technologies. Automation in this context means the handling and alignment of parts and tools within the entire process chain to achieve adjustment and alignment accuracies at a level well below 0.5 μm. The exact knowledge about the position and the condition of the work piece and its tool throughout the entire process chain, is the key issue in the automated production chain. This knowledge enables the exact referencing of the work piece within the machine tool coordinate system and an offset compensation by the machine tool axes as well as by active work piece clamping devices.

The automation solutions which are presented enable a cost effective, ultra high quality production technology for the achievement of nanometre form accuracies and super smooth surface finishes. These are required for ultra precise components in bio-medical-, sensor- as well as consumer goods applications and are revolutionary throughout the worlds technologies.

Keywords: micro optics, ultraprecision machining, sub-micrometer referencing

Novel Piezoresistive e-NOSE Sensor Array Cell

V.Stavrov(a), P.Vitanov(b), E.Tomerov(a), E.Goranova(b), G.Stavreva(a)
a: Nano ToolShop Ltd., Microelectronica Industrial Zone, 2140 Botevgrad, Bulgaria
b: Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, 72”Tzarigradsko chaussee”, blvd, 1784 Sofia, Bulgaria

Abstract

Future of analytical and manufacturing methods based on micro-mechanical cantilevers, depends critically on the ability to implement parallel operation and fast signal processing [1]. There are two mean reasons: high throughput requirement and complexity (multidimensionality) of analyzed value. In order to get parallel function, any single device should be simultaneously: recognizable, autonomously actuated and independently accessible for readout. Devices, fulfilling these requirements, are suffering from a substantial increase in complexity of both layout and manufacturing technology. In present paper, we demonstrate a novel design of a MEMS (Micro-Electro-Mechanical Systems) cell designed for e-NOSE applications, using results of previous works [2,3], which solves above mentioned problems.

The cell consists of four integrated cantilevers, each having a separate piezoresistor. Additionally, the cantilevers are designed to be different in length and thus having different resonance frequencies. Thus, individual cantilevers are frequency recognizable/addressable. Samples of self-actuated piezoresistive cantilever sensor have been fabricated on n-type, silicon, applying combined surface and bulk micromachining techniques. The cantilever dimensions were chosen to provide approx. 1.8 kHz resonance frequency gap between neighbor individual sensors. The new micro-machined cell is suitable for chemical and biological recognition as a micro-balance.

Keywords: cantilever, cantilever array, e-nose, piezo-resistive detection

New Systematic and Time-Saving Procedure to Design Cup Grinding Wheels for the Application of Ultrasonic Assisted Grinding

C. Brecher(a)(b), R. Schug(b), A. Weber(b), C. Wenzel(b)
a: Werkzeugmaschinenlabor (WZL), RWTH Aachen University, Germany
b: Fraunhofer-Institute for Production Technology, Aachen, Germany

Abstract

Since glass and ceramic materials have beneficial properties they gain more importance in all technical applications during the last thirty years. For example nowadays ceramics are used as artificial hip joints or as seals for highest relative speeds. Glass components are used for multitude of optical applications like cameras and reflectors. But besides a lot of advantages the processing of these materials is very difficult. Particular, this contains the manufacturing of small components like micro-reactor plates or glass wafers with hundreds of small holes, too.

Using ultrasonic assisted grinding the treatment can significantly be optimised and higher removal rates can be realised. For the generation of ultrasonic waves often piezo actors are used that excite the grinding tools with vibrations of 20 kHz and amplitudes of a few microns. Using an ultrasonic wave the tool geometry is strongly restricted to guarantee the hybrid functionality. The paper describes a new way to calculate the design of tools suitable for their use in ultrasonic assisted grinding. As a machining process the manufacturing of spherical optics with cup grinding wheels is selected.

Keywords: ultrasonic assisted grinding, method to design vibrating components, coupling of simulation tools

Characterization of Parylene-C Film as an Encapsulation Material for Neural Interface Devices

Jui-Mei Hsu(a), Sascha Kammer(b), Erik Jung(c), Loren Rieth(d), A. Richard Normann(e), Florian Solzbacher(a)(d)(e)
a: Department of Material Science and Engineering, University of Utah, Salt Lake City, UT, USA
b: Fraunhofer IBMT, St. Ingbert, Germany
c: Fraunhofer IZM, Berlin, Germany
d: Department of Electrical Engineering, University of Utah, Salt Lake City, UT, USA
e: Department of Bioengineering, University of Utah, Salt Lake City, UT, USA

Abstract

Neural interfaces, devices that interact with nervous system, have been developed to help patients with neural disorders to restore lost neural function. The neural interface device requires a conformal and biocompatible encapsulation layer to protect the device during chronic implantation, and to electrically isolate individual electrodes. Parylene-C thin films deposited by a chemical vapour deposition system were studied as an encapsulation layer for neural interface devices. Leakage current tests were used to investigate the encapsulation performance of Parylene-C films, and the results showed hermetic protection as well as long-term (>100 days) stability of the films. The adhesion between Parylene-C and the silicon substrate after several thermal treatments was studied by ASTM tape adhesion tests. Results from these tests suggested that thermal stress may degrade the adhesion force. Parylene samples were subjected to accelerated lifetime testing (85 % relative humidity (RH) and 85 °C) for 20 days, and the film did not show appearance changes as observed by optical microscopy. However, X-ray diffractograms show that the film crystallinity increased during this test.

Keywords: Parylene adhesion, biomedical device encapsulation, conformal coating

On the Development of an Implantable μ-Biomechatronic System for the Rehabilitation of Lower Limb Neuro-Muscular Disabilities

V. N. Syrimpeis(a), L.L. Chiou(a), V.C. Moulianitis(a), N.A. Aspragathos(a), E.C Panagiotopoulos(b)
a: Department of Mechanical Engineering and Aeronautics, University of Patras, Rio Patras 26500, Hellas
b: General University Hospital of Patras, Orthopedics Department, Rio Patras 26504, Hellas

Abstract

One of the current trends in the rehabilitation of lower limb neuromuscular disabilities is to use fully or partially implantable systems based on Functional Electrical Stimulation (FES). In this paper, the conceptual design of a possible fully or partially implantable system with submillimiter size is presented. The system presents increased flexibility, adaptability and comfortability. Preliminary results of the proposed control system in a simulation environment are presented and discussed.

Keywords: FES, biomechatronics, lower limbs