Electrical discharge machining (EDM) is a well-established machining option for manufacturing geometrically complex or hard material parts that are extremely difficult-to-machine by conventional machining processes. The non-contact machining technique has been continuously evolving from a mere tool and die making process to a micro-scale application machining alternative attracting a significant amount of research interests. In recent years, EDM researchers have explored a number of ways to improve the sparking efficiency including some unique experimental concepts that depart from the EDM traditional sparking phenomenon. Despite a range of different approaches, this new research shares the same objectives of achieving more efficient metal removal coupled with a reduction in tool wear and improved surface quality. This paper reviews the research work carried out from the inception to the development of die-sinking EDM within the past decade. It reports on the EDM research relating to improving performance measures, optimising the process variables, monitoring and control the sparking process, simplifying the electrode design and manufacture. A range of EDM applications are highlighted together with the development of hybrid machining processes. The final part of the paper discusses these developments and outlines the trends for future EDM research.

http://zclient.persiangig.com/ScienceDirect/M02.pdf

State of the art electrical discharge machining (EDM)

New microproducts need the utilization of a diversity of materials and have complicated three-dimensional (3D) microstructures with high aspect ratios. To date, many micromanufacturing processes have been developed but specific class of such processes are applicable for fabrication of functional and true 3D microcomponents/assemblies. The aptitude to process a broad range of materials and the ability to fabricate functional and geometrically complicated 3D microstructures provides the additive manufacturing (AM) processes some profits over traditional methods, such as lithography-based or micromachining approaches investigated widely in the past. In this paper, 3D micro-AM processes have been classified into three main groups, including scalable micro-AM systems, 3D direct writing, and hybrid processes, and the key processes have been reviewed comprehensively. Principle and recent progress of each 3D micro-AM process has been described, and the advantages and disadvantages of each process have been presented.

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A review on 3D micro-additive manufacturing technologies

Additive manufacturing is a technology rapidly expanding on a number of industrial sectors. It provides design freedom and environmental/ecological advantages. It transforms essentially design files to fully functional products. However, it is still hampered by low productivity, poor quality and uncertainty of final part mechanical properties. The root cause of undesired effects lies in the control aspects of the process. Optimization is difficult due to limited modelling approaches. Physical phenomena associated with additive manufacturing processes are complex, including melting/solidification and vaporization, heat and mass transfer etc. The goal of the current study is to map available additive manufacturing methods based on their process mechanisms, review modelling approaches based on modelling methods and identify research gaps. Later sections of the study review implications for closed-loop control of the process.

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Additive manufacturing methods and modelling approaches: a critical review

Tool Condition Monitoring (TCM) — The Status of Research and Industrial Application

This paper is a survey of the presently available literature on disassembly sequencing, including the papers that are closely related to this topic. Disassembly theory is applied to complex products such as mechanical, electromechanical and electronic appliances. It is required for end-of-life processing and for maintenance and repair. Apart from these applications, disassembly is studied for supporting the analysis of assembly processes. Disassembly sequencing involves the search for all possible disassembly sequences and the selection of the optimum solution out of these. In each application, a slightly different approach can be observed, including level of detail, degrees of freedom, and the role of uncertainty. Disassembly sequencing also plays a major role in the modern design process and is an invaluable tool in concurrent engineering. Its connection with the more detailed or component level and the less detailed level or process level including logistics, is highlighted. This presentation of the state of the art is intended as a stimulus for further research in this interesting field.

Disassembly sequencing : a survey

Summary We studied the three-dimensional (3D) deformities in patients with congenital facial anomalies, such as cleft lip and palate or hemifacial microsomia using three-dimensional CT (3DCT) images. At the same time, the data from the 3DCT was processed and analyzed using a 3DCT measurement system which we have recently developed. The coordinates of the 67 test points on the craniofacial bones were determined on a 3D image prepared by the 3DCT measurement system. Using this system, we prepared the ‘skeletograms’, which present deformities of craniofacial bones in detail as a 3D wire frame model, for detailed analysis of the craniofacial bones' deformities.

Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

In this paper, a new digital watermarking method for vector maps is proposed, where the watermark can be embedded in a set of polylines by using the discrete Fourier transform (DFT). The robustness against external attacks and visual degradation caused by embedding were evaluated, and the effectiveness of the watermarking was confirmed. Our watermarking method is especially robust against vertex reordering attacks and noise imposition on the vertex coordinates.

Copyright protection of vector map using digital watermarking method based on discrete Fourier transform

A New Method for Detecting the Contact Point between a Touch Probe and a Surface

Development of Numerical Contouring Control Electric Discharge Machining (NCC-EDM)

In the industrial use of stereolithography, precision is always a problem. The basic phenomenon of solidification shrinkage has not been sufficiently investigated. This study aims at clarifying the initial linear shrinkage of cured resin in a minute volume. Experimental equipment has been developed which measures the time history of the single strand in situ in a stereolithography machine. An analysis model of the time history of a minute volume linear shrinkage was shown using the measured shrinkage of a cured line segment. The relation between the time history of the linear shrinkage and temperature was measured and the shrinkage in the minute volume after irradiation was found to result due to temperature variation. Deformation and linear shrinkage were measured with two scanning orders to control the thermal distribution in layer forming. The effects of thermal distribution were also observed in one layer forming.

Takeshi Kishinami

Papers

Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

Copyright protection of vector map using digital watermarking method based on discrete Fourier transform

A New Method for Detecting the Contact Point between a Touch Probe and a Surface

Development of Numerical Contouring Control Electric Discharge Machining (NCC-EDM)

Reaction heat effects on initial linear shrinkage and deformation in stereolithography