• Transactions of Materials Processing
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• v.4 no.4
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• pp.335-344
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• 1995

In this paper, an experimental study of a hot forging process is carried out using plasticine and the die set manufactured with the aid of rapid prototyping. In order to manufacture the die set, Stereolithography Apparatus(SLA) which is most widely used rapid prototyping system is introduced. Turbine blade forging is performed using palsticine and the SLA prototype die set. Through the experiment, it has been shown that SLA prototype is suitable to the die set for the plasticine workpiece, and the formability and the forming load of turbine blade forging are predicted.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.753-756
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• 2005

Rapid prototyping (RP) technologies are mainly performed by layered manufacturing (LM) process which manufactures 3D physical objects by depositing 2D sections in a direction. Thus, deformations are apt to occur in overhanging area of the RP processed part. Also, excessive adhesion between part and platform of the RP apparatus is generated. In order to prevent these problems, most of the RP technologies adopt support structure. Main element to support a part in the support structure is strand. In actual field, however, the number of strand is determined by the software operating reference guide or RP system operator's experience. In this paper, a methodology to determine the optimal strand spacing is presented through experiments and measurements for the SL part deformation by change of strand spacing and part weight in the support structure of the stereolithography.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.10
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• pp.917-923
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• 2015

3D Printing has a great advantage for its capabilities in manufacturing complicated structures in a reasonable manufacturing time, and thus is widely used in various fields. Due to the high cost of the equipment and material, a fairly acceptable equipment, the Projection Stereolithography Apparatus (PSLA), has been developed, using the projection pattern approach for the purpose of quick manufacturing. We evaluated its surface quality, as compared with that of other systems. The result is the development of a high-performance, low-cost 3D Printer and its operating software, using LCD and UV LED. Working materials for an optimal manufacturing are suggested in the research, along with some suggestions of basic approaches for enhancing the accuracy and quality of the manufactured structures.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.146-154
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• 1996

In this work, rapid prototyping and three-dimensional finite element analysis are simultaneously applied to the die design of metal forming processes. Rapid prototyping is a new prototyping technology which produces three-dimensional part models directly from CAD data and has been extensively applied to various manufacturing processes. There are many types of rapid prototyping systems due to their building principles and materials. In this work, Stereolithography Apparatus(SLA), which is the most widely used rapidprototyping system, is introduced to manufacture the die set. For general preparation of STL file, which is the standard input file of rapid prototyping system, mesh data which are used in describing the die surface in finite element analysis are translated so that rapid prototyping and finite element analysis are dffectively connected. A die set for spider forging and a clover punch for deep drawing section are manufactured effciently using SLA prototypes, and metal forming experiments are carried out using them. Comparing the result of experiments with that of analyses, the processes can be predicted and designed successfully.

• Tribology and Lubricants
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• v.37 no.1
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• pp.1-6
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• 2021

This paper presents the experimental results of hydrophobic surfaces developed using a stereolithography-based additive-manufacturing technique. The additive manufacturing technique can be used to manufacture objects with complex geometries from computer-aided design data. Several additive manufacturing methods, such as selective laser sintering, fused deposition modeling, stereolithography apparatus (SLA), and inkjet-based system, have been developed. The SLA is a form of three-dimensional printing technology used to create prototypes, patterns, and production parts in successive layers through photochemical processes. Light causes chemical monomers and oligomers to cross-link together to form objects composed of polymers. Moreover, this method is economical for fabricating surfaces with high output resolution and quality. Here, we fabricate various surfaces using different shapes using an SLA. The surfaces with micro-patterns are fabricated for 10 cases, including the biomimetic surface. The fabricated surfaces with various micro-patterns are evaluated for hydrophobicity performance based on the static contact angle. The contact angle is measured three times for each case, and the averaged value is used. The results indicate that the arrangements in a staggered structure have a larger contact angle than those in a line when the same micro-pattern is applied. Moreover, the mimetic surfaces exhibit more hydrophobic characteristics than those of artificial micro-patterns.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.907-910
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• 1995

Though SLA(Stereolithography Apparatus) is being recognized as an innovative technology, it still can not be used to fully practical applications since it lacks of dimensional accuracy compared to conventional processes. In SLA, the accuracy of cured part depends upon the set of process parmeters. In order to improve the accuracy of SLA, this paper quantitatively evaluates how largely each process parameter of SLA contributes to the part accuracy and estimates the optimal set of process parameter which minimizes the dimensional errors of the test part, "letter-H" part. For this purpose, we use ANOVA(analysis of variance) and S/N(signal-to-noise)ratio of Taguchi method.hi method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.10
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• pp.3068-3078
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• 1996

stereolithography is a process used to rapidly produce polymer components directly from a computer representation of the part. There are several considerations to be made for the efficient use of the process. Especially, the necessity of support structures, which prevent the part from warping, sagging, or parachuting and toppling as the elevator moves up and down in the resin, is one concern. After solidification, the support structures must by removed in the end. Bacause this post-treatment process is often performed manually, the more the support structures, the more it increases the finishing operations. Especially for a complicated part, the removal operations may be difficult, take so much time, and even reduce the accuracy of the product. Thus it is important to efficiently generate the efficient support structure for each part geometry. This paper proposes a procedure to automatically generate the supprot structures focused on accuracy, efficiency, convenience, and generation speed.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.19-25
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• 1999

This paper addresses a development work of a SLA apparatus on laboratory basis. The SLA test machine is composed of optical, movement, curing and control subsystems. Optical part is performed by a He-Cd laser with mirror combination and mechanical movement is achieved by X-Y table. The developed system is evaluated by several test runs, and shows a good precision capability in forming a basic part. The technique used in this work can be extended to replace the high technology transfer cost of commercial RP machine.

• Journal of Korean Institute of Industrial Engineers
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• v.18 no.1
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• pp.63-80
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• 1992

The concept of rapid prototyping intended for a significant reduction in cost and lead time becomes even more practical with the recent development of various equipments to make the concept concrete. For the purpose of real application of commercially available SLA(stereolithography apparatus), this paper is intended to develop the standard conversion procedure from CAD data to the input data for SLA. While the procedure presented in this paper is based on CAD system "CATIA" and SLA of 3D systems, Inc., which are being used in authors' company DAEWOO Motor Co., Ltd., the basic concept of this paper can be applied to any other CAD systems and machines of using stereolithography process. The algorithm presented in this paper is classified into two stages-node sampling and triangulation. First of all, point data are sampled through the node sampling procedure, and then these are triangulated so that the input data for SLA operation is finally generated. The suggested method is devised in a way to meet the input requirements of SLA and more importantly consume less computation time and generate less number of input data for SLA.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.3
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• pp.61-67
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• 1998

Rapid prototyping becomes widely used in design and manufacturing of mechanical and aerospace engineering. Here a drag valve disk consisted of complicate configuration has designed by CAD, and prototyped by a stereolithography apparatus (SLA) to confirm the design configuration. Also the prototyped valve disk was used for checking if it could be applied for casting from the view point of accuracy, cost, and time. The rapid-prototyped disk by SLA was compared with a high-speed machined disk by MAKINO V55, and it is found that the prototyping of the disk by SLA appears more economical, more accurate and faster than by machining with MAKINO V55.