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Article

Anand M.B. and Vinodh S.

The purpose of this study is to rank additive manufacturing (AM) processes for microfabrication using integrated fuzzy analytic hierarchy process (AHP)-technique for order…

Abstract

Purpose

The purpose of this study is to rank additive manufacturing (AM) processes for microfabrication using integrated fuzzy analytic hierarchy process (AHP)-technique for order of preference by similarity to ideal solution (TOPSIS).

Design/methodology/approach

AM technology selection is formulated as multi-criteria decision-making (MCDM) problem and ranking is obtained using fuzzy AHP-TOPSIS. Five candidate processes considered are laser-induced forward transfer (LIFT), microstereolithography, micro-selective laser sintering (micro-SLS), inkjet, micro 3D printing.

Findings

Criteria weights are obtained using fuzzy AHP, and ranking is obtained using fuzzy TOPSIS. The top ranked criteria include material compatibility, geometrical complexity and minimum feature size. The ranking sequence is LIFT > microstereolithography > micro-SLS > inkjet > micro-3D printing.

Research limitations/implications

In the present study, ten criteria and five alternatives are used. In future, additional criteria and alternatives could be considered in line with technological advancements.

Practical implications

The generated ranking enabled the selection of appropriate AM process for microfabrication.

Originality/value

The application of hybrid MCDM approach for ranking AM processes for microfabrication is the contribution of the study.

Details

Rapid Prototyping Journal, vol. 24 no. 2
Type: Research Article
ISSN: 1355-2546

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Article

Muthukumaran Packirisamy

To predict the influence of inherent microfabrication and operating environmental influences on the performance of capacitive type sensors and actuators so that one can…

Abstract

Purpose

To predict the influence of inherent microfabrication and operating environmental influences on the performance of capacitive type sensors and actuators so that one can tune the performance and carry out more realistic designs.

Design/methodology/approach

When the sensors and actuators are micromachined or microfabricated, they are subjected to special problems that are characteristic to microdimensions. The important concerns are the influence of microfabrication process on the material properties and influence of operating environment on the system behavior. Hence, this paper proposed a way of quantifying and modeling the influence of inherent limitations of microfabrication and operating environment for the better design of micromachined capacitive type sensors and actuators. The methodology applies the modeling the variation of the elastic property of the system due to above influences through elastic stiffening and weakening concepts. The approach includes the application of boundary conditioning concept through Rayleigh energy method.

Findings

The microfabrication process and electrostatic field can alter significantly both static and dynamic behavior of the device. The performance of the device could also be tuned through these influences.

Research limitations/implications

As the displacement of the sensors is expected to be small, linear approach is applied. The sensitivity, output range, operating limits and natural frequencies of the sensor can be easily controlled by varying the process and operating environmental influences.

Practical implications

Improved and more realistic design of microfabricated capacitive type sensors and actuators for many applications, such as, pressure sensors, microphones, microspeakers, etc.

Originality/value

A simple and easy way of modeling and quantifying the influence of process and operating environment was proposed for the betterment of design. The proposed design method can be applied for any micromachined or microfabricated capacitive type sensors and actuators so that varying sensitivities, output ranges and natural frequencies could be obtained. Over the last few years, newly emerging micro‐electro‐mechanical‐systems (MEMS) technology and micro‐fabrication techniques have gained popularity and importance in the miniaturization of a variety of sensors and actuators. The proposed technique is very useful in making the field of MEMS more matured as it attempts to model the problems that are unique to MEMS environment.

Details

Sensor Review, vol. 26 no. 1
Type: Research Article
ISSN: 0260-2288

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Article

Gary Hunter, Randy Vander Wal, Laura Evans, Jennifer Xu, Gordon Berger, Michael Kullis and Azlin Biaggi‐Labiosa

The development of chemical sensors based on nanostructures, such as nanotubes or nanowires, depends on the capability to reproducibly control the processing of the…

Abstract

Purpose

The development of chemical sensors based on nanostructures, such as nanotubes or nanowires, depends on the capability to reproducibly control the processing of the sensor. Alignment and consistent electrical contact of nanostructures on a microsensor platform is challenging. This can be accomplished using labor‐intensive approaches, specialized processing technology, or growth of nanostructures in situ. However, the use of standard microfabrication techniques for fabricating nanostructured microsensors is problematic. The purpose of this paper is to address this challenge using standard photoresist processing combined with dielectrophoresis.

Design/methodology/approach

Nanostructures are suspended in photoresist and aligned between opposing sawtooth electrode patterns using an alternating current (AC) electric field (dielectrophoresis). The use of photoresist processing techniques allow the burying of the nanostructures between layers of metal, thus improving the electrical contact of the nanostructures to the microsensor platform.

Findings

This approach is demonstrated for both multi‐walled carbon nanotubes and tin oxide nanowires. Preliminary data show the electrical continuity of the sensor structure as well as the response to various gases.

Research limitations/implications

It is concluded that this approach demonstrates a foundation for a new tool for the fabrication of microsensors using nanostructures, and can be expanded towards enabling the combination of common microfabrication techniques with nanostructured sensor development.

Originality/value

This approach is intended to address the significant barriers of deposition control, contact robustness, and simplified processing to realizing the potential of nanotechnology as applied to sensors.

Details

Sensor Review, vol. 32 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

C. De Maria, L. Grassi, F. Vozzi, A. Ahluwalia and G. Vozzi

This paper aims to develop a novel micro-ablation system to realise micrometric and well-defined hydrogel structures. To engineer a tissue it is necessary to evaluate…

Abstract

Purpose

This paper aims to develop a novel micro-ablation system to realise micrometric and well-defined hydrogel structures. To engineer a tissue it is necessary to evaluate several aspects, such as cell-cell and cell-substrate interactions, its micro-architecture and mechanical stimuli that act on it. For this reason, it is important to fabricate a substrate which presents a microtopology similar to natural tissue and has chemical and mechanical properties able to promote cell functions. In this paper, well-defined hydrogel structures embedding cells were microfabricated using a purposely developed technique, micro-laser ablation, based on a thulium laser. Its working parameters (laser power emission, stepper motor velocity) were optimised to produce shaded “serpentine” pattern on a hydrogel film.

Design/methodology/approach

In this study, initially, swelling/contraction tests on agarose and alginate hydrogel in different solutions of main components of cell culture medium were performed and were compared with the MECpH model. This comparison matched with good approximation experimental measurements. Once known how hydrogel changed its topology, microstructures with a well-defined topology were realised using a purposely developed micro-laser ablation system design. S5Y5 neuroblastoma cell lines were embedded in hydrogel matrix and the whole structure was ablated with a laser microfabrication system. The cells did not show damages due to mechanical stress present in the hydrogel matrix and to thermal increase induced by the laser beam.

Findings

The hydrogel structure is able to reproduce extracellular matrix. Initially, the hydrogel swelling/contraction in different solutions, containing the main components of the most common cell culture media, was analysed. This analysis is important to evaluate if cell culture environment could alter microtopology of realised structures. Then, the same topology was realised on hydrogel film embedding neuronal cells and the cells did not show damages due to mechanical stress present in the hydrogel matrix and to thermal increase induced by the laser beam. The interesting obtained results could be useful to realise well-defined microfabricated hydrogel structures embedding cells to guide tissue formation

Originality/value

The originality of this paper is the design and realisation of a 3D microfabrication system able to microfabricate hydrogel matrix embedding cells without inducing cell damage. The ease of use of this system and its potential modularity render this system a novel potential device for application in tissue engineering and regenerative medicine area.

Details

Rapid Prototyping Journal, vol. 20 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

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Article

Javad Dargahi, Mojtaba Kahrizi, Nakka Purushotham Rao and Saeed Sokhanvar

To measure the force applied to the tissue, the traditional endoscopic graspers might be equipped with a kind of tactile force sensor.

Abstract

Purpose

To measure the force applied to the tissue, the traditional endoscopic graspers might be equipped with a kind of tactile force sensor.

Design/methodology/approach

This paper presents the design, analysis, microfabrication and testing of a piezoelectric and capacitive endoscopic tactile sensor with four teeth. This tactile sensor, which is tooth‐like for safe grasping, comprises a Polyvinylidene Fluoride, PVDF film for high sensitivity and is silicon‐based for micromachinability. Being a hybrid sensor, employing both capacitive and piezoelectric techniques, it is possible to measure both the static and dynamic loads. Another feature, to be considered in its design, is the ability to detect pulse. The proposed sensor can be integrated with the tip of any current commercial endoscopic grasper without changing its original design. It is shown that using an array of sensor units, the position of the applied load can still be determined.

Findings

The static response of the sensor is obtained by applying a static force on the tooth and measuring the change in capacitance between the bottom electrode of the PVDF film and the electrode deposited on the surface of the etched cavity. The dynamic response of the device is determined by applying a sinusoidal force on the tooth of the sensor and measuring the output voltage from the PVDF film. The experimental results are compared with both analytical and finite element results. The sensor exhibits high sensitivity and linearity.

Originality/value

Capaciyive and piezoelectic are used to obtain both dynamic,pulse, and static loads. The sensor micromachined so, it can be used in various endoscopic applications.

Details

Sensor Review, vol. 26 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

Victor A. Lifton, Gregory Lifton and Steve Simon

This study aims to investigate the options for additive rapid prototyping methods in microelectromechanical systems (MEMS) technology. Additive rapid prototyping…

Abstract

Purpose

This study aims to investigate the options for additive rapid prototyping methods in microelectromechanical systems (MEMS) technology. Additive rapid prototyping technologies, such as stereolithography (SLA), fused deposition modeling (FDM) and selective laser sintering (SLS), all commonly known as three-dimensional (3D) printing methods, are reviewed and compared with the resolution requirements of the traditional MEMS fabrication methods.

Design/methodology/approach

In the 3D print approach, the entire assembly, parts and prototypes are built using various plastic and metal materials directly from the software file input, completely bypassing any additional processing steps. The review highlights their potential place in the overall process flow to reduce the complexity of traditional microfabrication and long processing cycles needed to test multiple prototypes before the final design is set.

Findings

Additive manufacturing (AM) is a promising manufacturing technique in micro-device technology.

Practical implications

In the current state of 3D printing, microfluidic and lab-on-a-chip devices for fluid handling and manipulation appear to be the most compatible with the 3D print methods, given their fairly coarse minimum feature size of 50-500 μm. Future directions in the 3D materials and method development are identified, such as adhesion and material compatibility studies of the 3D print materials, wafer-level printing and conductive materials development. One of the most important goals should be the drive toward finer resolution and layer thickness (1-10 μm) to stimulate the use of the 3D printing in a wider array of MEMS devices.

Originality/value

The review combines two discrete disciplines, microfabrication and AM, and shows how microfabrication and micro-device commercialization may benefit from employing methods developed by the AM community.

Details

Rapid Prototyping Journal, vol. 20 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

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Article

Zhu Feng, Shaotao Zhi, Xuecheng Sun, Lili Yan, Cui Liu and Chong Lei

This paper aims to investigate the influence of structure parameters on giant-magnetoimpedance (GMI) effect measured by non-contact method.

Abstract

Purpose

This paper aims to investigate the influence of structure parameters on giant-magnetoimpedance (GMI) effect measured by non-contact method.

Design/methodology/approach

The GMI sensor contains a Co-based internal magnetic core fabricated by laser cutting and an external solenoid. The influences of magnetic permeability of magnetic core and structure parameters on GMI effect were calculated in theoretical model. The output impedance, resistance, reactance and GMI ratio were measured by non-contact method using impedance analyzer.

Findings

Enhancing external magnetic field intensity can decrease the magnetic permeability of core, which has vital influences on the magnetic property and the output response of GMI sensor. In addition, increasing the width of magnetic core and the number of solenoid turns can increase the maximum GMI ratio. The maximum GMI ratio is 3,230% with core width of 6 mm and solenoid turns of 200.

Originality/value

Comparing with traditional contact-measured GMI sensor, the maximum GMI ratio and the magnetic field sensitivity are improved and the power consumption is decreased in non-contact measured GMI sensor. GMI sensor measured by non-contact method has a wide range of potential applications in ultra-sensitive magnetic field detection.

Details

Sensor Review, vol. 40 no. 6
Type: Research Article
ISSN: 0260-2288

Keywords

Abstract

Details

Sensor Review, vol. 27 no. 1
Type: Research Article
ISSN: 0260-2288

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Article

Muthukumaran Packirisamy, Ion Stiharu, Xing Li and Gino Rinaldi

To establish an accurate and sensitive method to characterize the moisture content of a particular environment.

Abstract

Purpose

To establish an accurate and sensitive method to characterize the moisture content of a particular environment.

Design/methodology/approach

This paper proposes a relatively simple humidity sensor design consisting of electrodes on a suitable substrate coated with a polyimide material. The changes in relative humidity are denoted by a corresponding change in the polyimide material's electrical resistance profile. The design proposed in this work can be microfabricated and integrated with electronic circuitry. This sensor can be fabricated on alumina or silicon substrates. The electrode material can be made up of nickel, gold or aluminum and the thickness of the electrodes ranges typically between 0.2 and 0.3 μm. The sensor consists of an active sensing layer on top of a set of electrodes. The design of the electrodes can be configured for both resistive and capacitive sensing.

Findings

The polyimide material's ohmic resistance changes significantly with humidity variations. Changes in resistance as large as 4‐6 orders of magnitude are attainable over the entire operational humidity range.

Research limitations/implications

As the sensitivity varies non‐linearly with the humidity, the measurement has to be carried out over a very wide range in order to calibrate the sensor. The sensitivity and output range of the sensor can be easily controlled by changing the electrode spacing or geometry.

Practical implications

The control of humidity is important in many applications ranging from bio‐medical to space exploration.

Originality/value

A simple, easy to fabricate and measure, and low cost resistive‐type humidity sensor was developed. The realized sensor is suitable for integrating with microfabrication. Hence, multiple sensors of varying sensitivities and output ranges could be integrated on the same chip. Over the last few years, newly emerging micro‐electro‐mechanical‐systems technology and micro‐fabrication techniques have gained popularity and importance in the miniaturization of a variety of sensors and actuators.

Details

Sensor Review, vol. 25 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

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Article

L. Lin and X. Bai

Recent years have seen a rapid development of ink‐jet printing technology. This paper reviews the state‐of‐the‐art in ink‐jet printing technology and gives an overview of…

Abstract

Recent years have seen a rapid development of ink‐jet printing technology. This paper reviews the state‐of‐the‐art in ink‐jet printing technology and gives an overview of ink‐jet printing into the immediate future. The focus is placed on various applications of jet printing technology. The potential of applying jetting technology in the conventionally surface coating dominated applications will also be explored.

Details

Pigment & Resin Technology, vol. 33 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

1 – 10 of 220