Papers by Keyword: Micro Machining

Abstract: Micro/nanofabrication with less damage has been raised as a challenging issue in advanced micro/nanomanufacturing industries. Recently, a new hybrid laser-waterjet machining technology has been developed, in which material is removed by laser heating and softening and waterjet cooling and expelling with negligible thermal damage to the workpiece. An optimization of the process parameters, such as laser pulse energy, laser pulse overlap, focal plane position, and waterjet offset distance, in the machining of silicon using this hybrid technology is presented in this study. Grey relational analysis based on an orthogonal array is employed to optimize the multi-performance characteristics, where the groove width and heat-affected zone are minimized while the groove depth is maximized.

Abstract: To remove the shortcomings from the manufacturing process it is necessary to optimize all process parameters, for all stages of technological process: the exposure, the development, the electroforming and removal of the exposed SU8. This research implies that various types of MEMS devices can be developed at a high accuracy with design flexibility, only if all process parameters are optimized. This article is presenting a study regarding typical errors arisen during manufacturing of micro-parts using UV-LIGA technology.

Abstract: Ultra-hard AlMgB₁₄ (30-50 GPa) thin films were deposited on silicon substrate for a nominal thickness of 100 nm using a pulsed excimer laser and then subjected to direct micromachining using a 532 nm, 30 picosecond pulsed Nd:YAG laser. The application is targeted towards synthesizing an artificial nacre material composed of hexagonal bricks and particle bridges of superhard AlMgB₁₄ thin film and mortars of Ti thin film that biomimic the hierarchical architecture of natural nacre. The effects of pulse energy (0.1 to 1 μJ) and laser scanning speed (0.5 to 1.5 m/sec) on ablation depth and quality of scribed channels were evaluated. The morphology of the channels was characterized using confocal microscope and optical profilometer. Results indicated a clean material removal process characterized by absence of heat affected zone, high-speed scribing and small feature size. The energy fluence for the removal of 100 nm thin film without affecting the silicon substrate was 0.3 J/cm². An interesting observation is that particulate matter present in the thin film was not ablated suggesting a size effect. Analysis of thermal transport reveals that the material removal has occurred via spallation and phase explosion mechanisms. The picosecond laser thus offers a high-speed energy source for precisely ablating ultra-hard thin films that in turn will allow the potential for fabrication of novel artificial nacre with exceptional strength and toughness.

Abstract: With the ever-growing demand for micro products, the influence of micro-features and the functional performance of component surfaces represent a high economical potential. A competitive process for the manufacture of micro products is using micro end mills and a desktop milling machine. Since the topography of machined surfaces affects e.g. the wetting interaction or the bacterial cell adhesion, all relevant finishing steps such as the generation of a plane surface parallel to the machining table and the structuring with micro end mills have to be concerned in order to create functional surfaces. In this paper the generation of plane surfaces and chosen tool paths is described first and then the use of ultra-small micro end mills for slot milling in cp-titanium and the influence of process parameters on bottom surface quality is discussed.

Abstract: Electrochemical machining (ECM) is an anodic dissolution process of metal as anode ion by ion, and micro-ECM is a promising micromachining method at micro to meso-scale. Thus, a micro-ECM setup was developed to fabricate micro parts and explore the feasibility of micro-ECM at micro to meso-scale, including the design of high-frequency micro-energy pulse power supply. By using the detection unit of machining state and optical encoder, a closed loop control system for micro-ECM was developed. Under low concentration of passivating electrolyte, low machining voltage, micro rotating electrode and high-frequency short-pulse current, the machining gap can be reduced to about 10μm. The influence factors of the additives and the rotation of micro electrode on micro ECM were analysed by experiments. A micro-hole about 30μm in diameter was drilled by the rotating micro electrode.

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Abstract: Numerical controlled high speed micromachining on desktop machines is known to induce inherently new types of errors and machining issues at micro scale. The sources of these errors are either not known, or difficult to be modeled. Some of these errors are due to the downscaling effect of machine elements to a small micro-machine. This paper attempts to explore key issues proper to micro machines that are different from standard scale NC machine tools. Experimental observations are shown to support the discussion. The knowledge gained from these phenomena is used to nurture the design methodologies of micro-scale machines, to plan a suitable tool path and hence to improve the micromachining quality. This will also ascertain the statement that direct downscaling of current machine tools is worthless.

Abstract: This paper introduces the design, manufacturing and tests of a new CNC desktop milling machine dedicated to micro and meso-scale components. The paper discusses two types of micro-machine structure i.e. egg shape bridge and cantilever egg shape column. Both structures have been designed using an enhanced deterministic design method combining FEM and Taguchi methods. This has led to achieve tight geometric and kinematic errors and secured high machining accuracy observed in a couple of samples milled on the micro-machine.

Abstract: Micro machining becomes more and more important with the tendency of miniaturization of components used in various fields from military to civilian applications. The finite element method software Abaqus is used to model the nonlinear thermal force coupled elastic-plastic micro machining processes. Relatively systematic simulation analysis has been introduced based on the model combining the Johnson-Cook failure criteria, element deletion strategy etc. It reveals that the size effect is dominant while the depth of cut reaches the cutting edge radius. The rake angle plays more important roles on the micro machining than that of the cutting speed.

Abstract: A newly devised process using micro-electrochemical machining (MECE) is described as a recycling module in the current study. The purpose is the precise removal of In2O3SnO2 thin-film nanostructures from optical PET diaphragm surfaces for digital-paper surface. In the current experiment it was found that a large rotational diameter (Dc) for the cathode with a small gap width between the anode and the PET diaphragm surfaces was found to remove the In2O3SnO2 rapidly. A small edge radius of the cathode, or a short arc length of the anode, reduces the time taken for In2O3SnO2 removal. A high feed rate of the PET and adequate electrical power results in fast machining. Pulsed direct current improves dregs discharge and this is an advantage with a fast feed. A high electrode rotational speed also corresponds to faster removal of the In2O3SnO2 nanostructures. The development of the proposed precision production design is based on both technical and economic considerations.