Mechanical machining
Fabrication of piezoelectric thick-film bimorph micro-actuators from bulk ceramics using batch-scale methods
R.P.Jourdain and S.A.Wilson
Materials Department, School of Applied Sciences, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, United Kingdom
Abstract
Piezoelectric ceramic films in the 20-60 micron thickness range are rarely employed today in commercial micro-mechanical devices, even though their expected force capability suggests that they are well suited to many micro-fluidic and micro-pneumatic applications. Some examples would be micro-scale fuel cells and micro-combustors. Head sliders, radio-frequency (RF) micro-switches and powered micro-optics are further potential application areas. These are only a few and the barriers in bringing them into reality are those of processing compatibility rather than commercial desirability. Such issues are being addressed in the EU Framework 6 Project ‘Q2M’, which focuses on batch-scale fabrication issues for high quality new micromechanical devices that are cost-effective and which have extended capabilities.
This paper discusses a potential batch-scale production route for piezoelectric thick-film bimorph microactuators that combines ultra-precision grinding of ceramics and femto-second laser machining, along with standard micro-fabrication techniques such as wafer bonding. This new method has the key advantage that many different shapes and thicknesses of actuator can be made with only minor process changes, meaning that actuators can be designed to suit their intended application. It contrasts with current practice whereby micro-actuators are often designed around a limited range of standard components, with consequent reduction in their achievable performance. The examples used are a 6mm diameter plane-spiral bimorph actuator for integration into a polymeric micro-valve and 2-5mm long bimorph cantilevers intended for use in
a new type of silicon ‘house’ micro-valve, with pneumatic applications.
categories
actuators | Bimorph | ceramic based | femto-second | Mechanical machining | MEMS | micro-actuator | PZT | ultra-precision grinding | wafer bonding
| 133 reads | Double hot-embossing with polymeric intermediate mould
Chantal Khan Maleka, Gaël Thuilliera, Roland Duffaitb , Laurent Guyoutc
a Laboratoire FEMTO-ST, CNRS UMR 6174, Département LPMO, 32 Avenue de l’Observatoire, 25044 Besançon Cedex, France.
b Centre de Transfert des Micro et Nanotechnologies (CTMN), 39 Avenue de l’Observatoire, BP 1445-25007 Besançon Cedex 3, France.
c Department of Applied Mechanical Engineering, University of Franche Comté, 16 Route de Gray, 25030 Besançon Cedex, France.
Abstract
Our approach uses a two-step replication process for hot embossing and a rigid polymeric intermediate mould. This process overcomes some geometrical limitations in microstructured mould fabrication, enables positive-tone imprinting, prolongs the lifetime of the master, and lowers the overall cost of the replication process.
categories
hot-embossing | Hot/UV embossing | Mechanical machining | milling | milling | polymeric mould | polymers | ReplicationDevelopment 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.
DLC Based BioMEMS Probe for Electrical Activity Recording of Tissues and Cells
C. Moldovan(a), R. Iosub(a), C.P. Lungu(b), A.M. Lungu(b), B. Firtat(a), C. Roman(a), R. Albulescu(c
a: National Institute for Research and Development in Microtechnologies, IMT-Bucharest, 126A Erou Iancu Nicolae Street, 077190 Bucharest, Romania
b: National Institute for Laser, Plasma and Radiation Physics, POBox MG-36, Magurele, Bucharest, Romania
c: National Institute for Chemical-Pharmaceutical R&D, 112 Calea Vitan, Bucharest, Romania
Abstract
An implantable probe for electrical activity monitoring of living tissues was engineered and fabricated on a silicon chip at IMT-Bucharest, Romania. In order to improve the mechanical resistance and biocompatibility of the device, the technology of Thermionic Vacuum Arc (TVA) deposition was used for coating the implantable parts with diamond like carbon (DLC) with zero stress (0SC). The paper presents the design and manufacturing steps of an DLC based 8-channel microprobe for recording the electrical activity of neural cells and tissues. The specific fabrication processes of the integrated microprobe are presented. The microprobe was packaged using gold wire bonding, in order to allow the electrical signals reading and processing. The electronics implemented on the board accomplish the separation and reduction of the biological noise recording. The microprobe functionality was tested in vivo and in vitro, in specialized laboratories, by recording electrical signals from cells cultures and mice organs. Biocompatibility tests were performed on implantable microprobes, coated with DLC/0SC, introduced in cells cultures. The integrated microprobe for monitoring tissues electrical activity can be used in laboratories and research centres acting in the biomedical field, which study the cells growth and their response to physico-chemical stimuli, in hospitals and treatment centres for people suffering from neurological diseases.
categories
Mechanical machiningA Synopsis of U.S. Micro-Manufacturing Research and Development Activities and Trends
Kornel F. Ehmann(a)(b)(c)(d)
a: Department of Mechanical Engineering, Northwestern University, Evanston IL, USA
b: Department of Mechanical Science and Engineering, University of Illinois at Urbana/Champaign, USA
c: Department of Mechanical Engineering, Indian Institute of Technology – Kanpur, India
d: Department of Mechanical Engineering, Chung Yuan Christian University, Chung Li, Taiwan
Abstract
Micro-manufacturing in the context of this presentation is defined as the manufacture of components and products in the sub-millimeter to a few-millimeter range with micron size feature characteristics of high accuracy and precision in a wide range of engineering materials by non-lithography based processes. The paper addresses three topics. First, the findings of a worldwide study on micro-manufacturing, conducted by the World Technology Evaluation Center, Inc. (WTEC) will be summarized. This summary will compare U.S. efforts to those in a number of Asian and European countries. Second, a précis of selected ongoing work conducted at U.S. universities with leading programs in the field will be given. Topics to be discussed include the development of miniaturized machine tools for cutting, forming and manipulation as well as the modeling of micro-manufacturing processes. An account of the growing industrial activities related to the development of micro-manufacturing equipment will also be included. Third, emerging directions and challenges in the development of micro-manufacturing technologies will be reflected upon.
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