International Journal of Production Research. Nov2008, Vol. 46 Issue 22, p6431-6460. 30p. 15 Diagrams, 8 Charts, 1 Graph.
PROTOTYPES, RAPID prototyping, COMPUTER integrated manufacturing systems, INDUSTRIAL engineering, MATHEMATICAL models, PRODUCTION planning, and COMPUTER-aided process planning
This paper presents a generative process planning system for parts produced by the rapid prototyping process (i.e. fused deposition modelling-FDM). The proposed process planning involves optimal selection of orientating the model with a proper support structure and then provides an intelligent slicing methodology, such as direct or adaptive, to minimise the built up time, keeping the geometry and cusp height errors in control. Pre- and post-slicing processes have been used to minimise the sliced data error. The Computer Aided Process Planning (CAPP) model has been arranged into five modules: orientation, support structure generation, slicing, path planning and Numerical Control (NC) program generation, and model build up. The CAPP model has been implemented in C language having a unique methodology consisting of 42 simplified steps. The CAPP model has been tested for several examples and shows satisfactory results. [ABSTRACT FROM AUTHOR]
International Journal of Production Research. 1/1/2005, Vol. 43 Issue 1, p169-194. 26p. 7 Black and White Photographs, 5 Diagrams, 10 Charts.
RAPID prototyping, MANAGEMENT information systems, DECISION support systems, PROTOTYPES, and PRODUCTION engineering
A new method is proposed for selecting the most appropriate rapid prototyping process according to user's specific requirements by using the expert system and fuzzy synthetic evaluation. The selection process is divided into two stages. First, it is necessary to generate feasible alternatives, which are executed under the expert system environment. Second, given those feasible alternatives, the fuzzy synthetic evaluation approach is employed to produce a ranking order of the alternatives and to finalize the most suirapid prototyping system. One distinctive characteristic of this method is that quantitative as well as qualitative measures are employed, providing more accurate results. The decision system developed based on the proposed method is composed of four modules: a database to store the specifications of various rapid prototyping processes; a knowledge-based expert system for determining the feasible alternatives; a fuzzy synthetic evaluation model to select the most suitable rapid prototyping process; and a user interface and an expert interface to interact with the system. The fuzzy synthetic evaluation approach used in the system is illustrated in detail by a numerical example. Furthermore, a Java-enabled solution, together with web techniques, is employed for developing such a networked decision support system. Finally, two examples of rapid prototyping process selection are designed to demonstrate the application of the system. The system has been implemented and can run at a rapid prototyping and manufacturing networked service platform that the authors have developed. [ABSTRACT FROM AUTHOR]
A direct-slicing approach might improve the accuracy and quality of small, complex parts produced with rapid prototyping technology. An application software based on direct slicing for rapid prototyping was used on the foundation of PowerSHAPE models. Lines, conic arcs and cubic bezier curves were adopted as the basic elements describing the direct-slicing contours. Moreover, a scheme to carry out subdivided software development was proposed. A picture (PIC) format file was selected as an interface for the slicing data, and a macro-AutoSection software, which collects the direct-slicing contour data of arbitrary complex computer-aided design models and provides power to produce the direct-slicing PIC files, was developed. On the above basis, an application software called PDSlice based on direct-slicing data processing was developed for the commercial selective laser sintering machine HRPS-III, which was made at the Huazhong University of Science and Technology (HUST), P. R. China. The major input and output interfaces as well as the PIC model reconstruction method of the PDSlice are described. Furthermore, a batch of direct-slicing polymer parts were successfully fabricated with the selective laser sintering machine. The application example shows that the accuracy and surface finish of three-dimensional complex curvature surface parts fabricated with the application software system based on a direct-slicing format were better than the application software system based on a stereolithography (STL) format. [ABSTRACT FROM AUTHOR]
International Journal of Production Research. 1/20/2002, Vol. 40 Issue 2, p293-310. 18p. 16 Diagrams.
RAPID prototyping, COMPUTER-aided design, PROTOTYPES, FINITE element method, CAD/CAM systems, and LITHOGRAPHY
Rapid prototyping (RP) is an emerging, non-traditional fabrication method and has been recognized as a valid tool to shorten the lead-time from design to manufacture effectively. Most of the current RP systems adopt the triangular meshes of stereolithoraphy (STL) as a standard format for data input. Thus, the construction of triangular meshes directly affects the quality of RP parts and their subsequent processes. Traditionally, STL data are output from 3D CAD models built using commercial 3D CAD/CAM software packages. This study, however, differs from the traditional way in that it generates the STL data directly from scanned 3D data points, thus preventing various problems associated with 3D CAD modelling from a large quantity of data points. Specific tasks involved in this study include: (1) development of the methodology to convert massive data points into numerous, connected triangular meshes, (2) determination of unit normal vector for each triangular mesh facet, (3) output of triangular meshes with normal vectors in STL format, and (4) slicing of triangular-mesh model into a series of 2D sections. [ABSTRACT FROM AUTHOR]
The geometric description used to represent solid objects significantly affects the accuracy and quality of the final parts produced with rapid prototyping (RP) technology. This paper discusses the alternative method of adaptive direct slicing for RP. Direct slicing generates precise contours for each layer from the solid model and avoids an intermediate representation. Adaptive slicing modifies the layer thickness to take into account the curvature of the surface of the solid model in the vertical direction, to alleviate the staircase effect, and to decrease the number of layers. Thereby, adaptive direct slicing potentially enables part fabrication with higher accuracy and production efficiency. This paper presents a new, practical approach to adaptive direct slicing based on the area deviation ratio. The slicing strategy and algorithm are also described. The corresponding procedure was implemented and tested on Windows 95/98 and NT 4.0 with AutoCAD R14. [ABSTRACT FROM AUTHOR]
International Journal of Production Research. 3/1/2006, Vol. 44 Issue 5, p919-938. 20p. 4 Color Photographs, 8 Diagrams, 6 Charts, 2 Graphs.
RAPID prototyping, PRODUCTION engineering, MANUFACTURING processes, INDUSTRIAL engineering, POWDER injection molding, MARAGING steel, SINTERING, INJECTION molding of metals, MATERIALS, RESEARCH methodology, and METALLURGICAL research
In this research work, attempts have been made to design, develop and evaluate the performance of mould inserts for injection moulding by using a powder-sintering process. Maraging steel powder, sintering aid and binder are materials used in this proposed development process. Attempts have been made to perform in-depth studies and to apply the powder-sintering process, to eventually produce the final sintered components. In addition, an analysis of the dimensional accuracy of the respective stereolithography master models and an analysis of the sintered specimens during various stages of powder-sintering process have been carried out. The intelligent manufacturing systems (IMS) test part with minor modifications has been used in the evaluation of dimensional accuracy, tolerances, distortion and volumetric variations. The main reason for using this unique geometry is the suitability of its design for injection-moulding processes and tooling. [ABSTRACT FROM AUTHOR]