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The most commonly used input to a rapid prototyping (RP) system is the de facto stereolithography file (STL). Several problems plague these STL files owing to the very nature of STL files and the non-robustness of commercial CAD system model tessellators. The consequences of not correcting these errors are detrimental to the creation of the intended prototype. These are highlighted in the paper. In Part 1 of two papers, a description of all STL-files-related errors is given. The paper also proposed a generic solution to solve one of the major problems in the proper creation of a prototype, that is, the problem of missing facets. Part 2 deals with special cases of errors associated with the STL files. The performance evaluation of the proposed solution is also given. [ABSTRACT FROM AUTHOR]

The most commonly used input to a rapid prototyping (RP) system is the de facto stereolithography file (STL). Several problems plague these STL files owing to the very nature of STL files and the non-robustness of commercial CAD system model tessellators. The consequences of not correcting these errors are detrimental to the creation of the intended prototype. These are highlighted in the paper. In Part 1 of two papers, a description of all STL-files-related errors is given. The paper also proposes a generic solution to solve one of the major problems in the proper creation of a prototype, that is, the problem of missing facets. Part 2 deals with special cases of errors associated with the STL files. The performance evaluation of the proposed solution is also given. [ABSTRACT FROM AUTHOR]

Rapid prototyping processes produce parts layer by layer directly from the CAD model. The processes proceed by first slicing the geometric model of a part into layers. A standard interface is necessary to convey varied geometric descriptions from numerous CAD packages to Rapid Prototyping (RP) systems. The STL (STereoLithography) format is the most commonly used interface for this purpose. Unfortunately, it is an approximate model and is frequently not robust. Therefore, other interfaces are proposed to be used for RP systems. This paper, Part 1, will discuss several existing interfaces including the STL file for the RP systems. The strengths and weaknesses of these formats when used for RP systems are analysed. Furthermore, a new improved format is proposed by the authors in Part 2. In that paper, the design considerations and data structure of the new format are introduced. [ABSTRACT FROM AUTHOR]

The STL (STereoLithography) file format, as developed by 3D Systems, has been widely used by most Rapid Prototyping (RP) systems and is supported by all major computer-aided design (CAD) systems. However, it is necessary to improve the STL format to meet the development needs of RP technologies. In Part 1, several existing and proposed formats have been discussed. This paper, Part 2, will present an improved interface between CAD and RP systems. The new interface is a file format that supports the STL format, removes redundant information in the STL format and adds topological information to balance storage and processing cost. In addition to supporting facet boundary models, the new interface supports precise models by using the edge-based boundary representation. This paper discusses the design considerations of the new interface and data structures for both facet models and precise models. Finally, a comparison of the new interface and the STL file format will be made. [ABSTRACT FROM AUTHOR]

Connectors are developed to satisfy the needs of advanced technology in telecommunication switching systems and companies have several products designed to fulfil the needs of the many switching networks available. The “Four-wall-header” is one such product from one company. The traditional manufacturing line relies heavily on hard tooling which is both expensive and time-consuming. This paper presents an alternative method of integrating rapid prototyping technologies, in particular, stereolithography apparatus (SLA), with a vacuum casting system to produce a wide range of polyurethane parts. Altogether, three approaches are analysed and evaluated for making the moulds: rapid pattern, rapid tooling and a hybrid approach. [ABSTRACT FROM AUTHOR]

In recent years, new surgical techniques have been developed to improve the quality of operations, reduce the risk to patients and reduce the pain experienced by patients. Prominent developments include minimally invasive surgery, robot-assisted hip operations, computer-assisted surgery (CAS) and virtual reality (VR). These developments have helped surgeons operate under difficult visual conditions. Rapid prototyping (RP) technology has also found applications in medicine. The RP technique is able to fabricate a representative, physical 3D model. This 3D model can enhance interpretation, visual and physical evaluation, and the rehearsal and planning of the surgical steps before a surgical operation is carried out in order to eradicate the trauma. This paper presents the procedures involved in the conversion of computerised tomography (CT) scan data to a useful physical model. A case study of a CT scanned file of a patient who had an injury to the right eye socket is presented. Three different RP systems (SLA, SGC and LOM) are benchmarked for comparison in terms of the surface finish, accuracies, visual appearance and processing speed. Because of the ability of RP to fabricate models that are complex in design with intricate features that may be hidden by undercuts, as demonstrated in this paper, the results of this research can be extended to applications in general engineering. One specific area of application would be reverse engineering. [ABSTRACT FROM AUTHOR]