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

http://user.it.uu.se/~jarst116/slides/week4.pdf

Graph-Based Algorithms for Boolean Function Manipulation

Open Dynamics Engine を用いたスノーボードロボットシミュレータの開発

Features encapsulate the engineering significance of portions of the geometry of a part or assembly, and, as such, are important in product design, product definition, and reasoning, for a variety of applications. Feature-based systems have demonstrated some potential in creating attractive design environments and in automating the geometric reasoning required in applications such as process planning and manufacturability evaluation. The paper reviews the major concepts and approaches that are in use in feature-based modelling. Several methodologies are prevalent for creating feature models and databases. These fall broadly into the categories of interactive definition, automatic recognition/extraction, and design by features. Within each, there are several subcategories, which are discussed and compared in the paper. Also presented are several schemes popular for representing features. They include augmented graphs, syntactic strings in grammars, and objects in object-oriented programming. Feature interactions and validation issues are outlined. Attempts at developing feature taxonomies are also summarized.

Assessment of features technology

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 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.

Reaction heat effects on initial linear shrinkage and deformation in stereolithography

Development of a Bridge Inspection Support System Using Two-Wheeled Multicopter and 3D Modeling Technology

STEP-based quality diagnosis of shape data of product models for collaborative e-engineering

In order to realize the articulate link between design and manufacturing and a traceable manufacturing system, it is necessary to represent the semantics of information independently of any implementations. Moreover, the quality of data that represent information should be ensured during the product life cycle. A significant amount of research for machining process planning and machining feature extraction has been carried out to help realize an integrated CAD/CAPP/CAM system. However, all data are not used throughout product development processes. The Standard for the Exchange of Product model data (STEP) has also emerged as a viable method for product model data exchange among design activities. However, a consistent application for integrating design, process planning and machining for mechanical components based on STEP/AP set has not completely been developed thus far. In this research, the Digital Semantic Model that fulfills the above requirements is proposed. In this paper, modeling and implementation of Digital Semantic Model for 5-axis machining is reported.

Fumiki Tanaka

Papers

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

Reaction heat effects on initial linear shrinkage and deformation in stereolithography

Development of a Bridge Inspection Support System Using Two-Wheeled Multicopter and 3D Modeling Technology

STEP-based quality diagnosis of shape data of product models for collaborative e-engineering

Modeling and implementation of Digital Semantic Models for 5-axis machining application