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Transient Physical Effects in Electron Beam Sintering
The extensive use of the electron beam in manufacturing processes like welding or perforating
revealed the high potentials for also using it for solid freeform fabrication. First approaches like
feeding wire into a melt pool have successfully shown the technical feasibility. Among other
features, the electron beam exhibits high scanning speed, high power output, and beam density.
While in laser-based machines the fabrication is working in a stable way, transient physical
effects in the electron beam process can be observed, which still restrict process stability. For
instance, a high power input of the electron beam can result in sudden scattering of the metal
powder. The authors have developed an electron beam freeform fabrication system and examined
the above mentioned effects. Thus, the paper provides methods in order to identify, isolate and
avoid these effects, and to finally realize a reproducible process.Mechanical Engineerin
Roadmap for optofluidics
Optofluidics, nominally the research area where optics and fluidics merge, is a relatively new research field and it is only in the last decade that there has been a large increase in the number of optofluidic. applications, as well as in the number of research groups, devoted to the topic. Nowadays optofluidics applications include, without being limited to, lab-on-a-chip devices, fluid-based and controlled lenses, optical sensors for fluids and for suspended particles, biosensors, imaging tools, etc. The long list of potential optofluidics applications, which have been recently demonstrated, suggests that optofluidic technologies will become more and more common in everyday life in the future, causing a significant impact on many aspects of our society. A characteristic of this research field, deriving from both its interdisciplinary origin and applications, is that in order to develop suitable solutions a. combination of a deep knowledge in different fields, ranging from materials science to photonics, from microfluidics to molecular biology and biophysics,. is often required. As a direct consequence, also being able to understand the long-term evolution of optofluidics research is not. easy. In this article, we report several expert contributions on different topics. so as to provide guidance for young scientists. At the same time, we hope that this document will also prove useful for funding institutions and stakeholders. to better understand the perspectives and opportunities offered by this research field
A dynamics-driven approach to precision machines design for micro-manufacturing and its implementation perspectives
Precision machines are essential elements in fabricating high quality micro products or micro features and directly affect the machining accuracy, repeatability and efficiency. There are a number of literatures on the design of industrial machine elements and a couple of precision machines commercially available. However, few researchers have systematically addressed the design of precision machines from the dynamics point of view. In this paper, the design issues of precision machines are presented with particular emphasis on the dynamics aspects as the major factors affecting the performance of the precision machines and machining processes. This paper begins with a brief review of the design principles of precision machines with emphasis on machining dynamics. Then design processes of precision machines are discussed, and followed by a practical modelling and simulation approaches. Two case studies are provided including the design and analysis of a fast tool servo system and a 5-axis bench-top micro-milling machine respectively. The design and analysis used in the two case studies are formulated based on the design methodology and guidelines
3D-Printed Scanning-Probe Microscopes with Integrated Optical Actuation and Read-Out
Scanningâprobe microscopy (SPM) is the method of choice for highâresolution imaging of surfaces in science and industry. However, SPM systems are still considered as rather complex and costly scientific instruments, realized by delicate combinations of microscopic cantilevers, nanoscopic tips, and macroscopic readâout units that require highâprecision alignment prior to use. This study introduces a concept of ultraâcompact SPM engines that combine cantilevers, tips, and a wide variety of actuator and readâout elements into one single monolithic structure. The devices are fabricated by multiphoton laser lithography as it is a particularly flexible and accurate additive nanofabrication technique. The resulting SPM engines are operated by optical actuation and readâout without manual alignment of individual components. The viability of the concept is demonstrated in a series of experiments that range from atomicâforce microscopy engines offering atomic step height resolution, their operation in fluids, and to 3D printed scanning nearâfield optical microscopy. The presented approach is amenable to waferâscale mass fabrication of SPM arrays and capable to unlock a wide range of novel applications that are inaccessible by current approaches to build SPMs
Design and fabrication of biocompatible scaffolds for the regeneration of tissues
Regenerative medicine and tissue engineering attempt to repair or improve the biological functions of tissues that have been damaged or have ceased to perform their role through three main components: a biocompatible scaffold, cellular component and bioactive molecules. Nanotechnology provide a toolbox of innovative scaffold fabrication procedures in regenerative medicine. In fact, nanotechnology, using manufacturing techniques such as conventional and unconventional lithography, allows fabricating supports with different geometries and sizes as well as displaying physical chemical properties tunable over different length scales. Soft lithography techniques allow to functionalize the support by specific molecules that promote adhesion and control the growth of cells. Understanding cell response to scaffold, and viceversa, is a key issue; here we show our investigation of the essential features required for improving the cell-surface interaction over different scale lengths.
The main goal of this thesis has been to devise a nanotechnology-based strategy for the fabrication of scaffolds for tissue regeneration. We made four types of scaffolds, which are able to accurately control cell adhesion and proliferation. For each scaffold, we chose properly designed materials, fabrication and characterization techniques
Micro-manufacturing : research, technology outcomes and development issues
Besides continuing effort in developing MEMS-based manufacturing techniques, latest effort in Micro-manufacturing is also in Non-MEMS-based manufacturing. Research and technological development (RTD) in this field is encouraged by the increased demand on micro-components as well as promised development in the scaling down of the traditional macro-manufacturing processes for micro-length-scale manufacturing. This paper highlights some EU funded research activities in micro/nano-manufacturing, and gives examples of the latest development in micro-manufacturing methods/techniques, process chains, hybrid-processes, manufacturing equipment and supporting technologies/device, etc., which is followed by a summary of the achievements of the EU MASMICRO project. Finally, concluding remarks are given, which raise several issues concerning further development in micro-manufacturing
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