• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.1-6
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• 2000

As dies and molds have become more and more complicated in the recent years, the demand for lower cost and shorter production time is also growing stronger. Rapid prototyping and Tooling technologies are expected to be used for more rapid and lower cost tool fabrication. However the rapid tooling methods have not yet reached the level of application to the manufacturing of metallic dies and molds which require high dimensional accuracy. As the rapid tooling technology, there are the slurry casting, the powder casting, the direct laser sintering, and so on. Generally, in the slurry casting, the alumina powder and the water soluble phenol were mainly used. However, the mechanical properties of the phenol were not good enough to apply to molds directly. In this study, pure epoxy and two types of aluminium powder reinforced resin are applied to the slurry casting. The mechanical and thermal properties are better than phenol because the epoxy is the thermosetting resin. And mechanical characteristics such as shrinkage rate, hardness, surface roughness are measured for the sake of comparison. Metal powder reinforced resin molds are better than the resin tool form the viewpoint of shrinkage rate and hardness. Finally, it has been shown that the application possibility of this process is high, because the manufacturing time and cost savings are significant.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.10
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• pp.50-56
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• 2004

Finishing is the final process in molds manufacturing and consumes much process time. Also, it influences on surface quality of molds. But, there are few systematic methods to control the process. In this work, basic experiments were carried out to study the machining characteristics of the finishing tools. From the experiments, critical surface roughness and wear coefficient are suggested to reduce the number of finishing steps and to plan a systematic finishing procedure. Comparison experiments were carried out between the expert's method and the new method, which is based on the results of this research. From the experiments, it is verified that the systematic method takes less time and generates less form error in the machined surface than the worker's method.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.63-69
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• 2007

The high speed machining has been widely applied to manufacture dies and machine elements in industrial field. Especially, 5-axis milling has been employed to produce a wide range of turbine blades, impellers and complex molds. In this study, the machining characteristics of injection molds were investigated according to tool tilting angles in 5-axis milling. The cutting force and surface roughness were investigated with various tool tilting angles. When the tool tilting angle was over than 10 degree, the characteristics of cutting force and surface roughness were improved in machining of Al alloy.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.497-498
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• 2006

Powder Injection Molding (PIM) has recently been recognized as an advanced manufacturing technology for low-cost mass production of metal or ceramic parts of complicated geometry. With this regards, design technology of dental scaler tip PIM mold, which has complex shape, with the help of computer-aided analysis for powder injection molding process was developed. Compter aided analysis results, such as filling pattern, weldline formation, and air vent position prediction were investigated and eventually showed good agreements with experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.62-67
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• 1999

The RP&M(Rapid Prototyping and Manufacturing) is the most appropriate technology for the small-lot production system, in which the production cycle is getting shorter owing to various needs from consumers. Recently RP products which are made of plastics, wax, and paper are used to verify the design of samples. But these products cannot be applied to the real mold because the strength enough to be a mold cannot be given by soft materials such as plastics. So RP products are copied to AFR(Al powder Filled Resin) molds or metal molds, which is called the RP&M. In this paper, RP&M is applied to a casting process. A porous casting mold, which is made from ceramic powder and binder, is used for rapid tooling of aluminum shoes molds.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.283-288
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• 2021

Due to the 4th Industrial Revolution and the Digital Revolution, many changes are being made in the manufacturing method and structure in the field of plastic arts and crafts. Therefore, in this study, we tried to present a new work method suitable for this era by effectively utilizing the digital technology called 3D printer. For this study, first of all, the theoretical background of 3D printing technology was understood, and prior studies on the use cases of 3D printing technology were summarized. Based on this, three types of craft molds were produced using a 3D printer. As a result of the study, there were characteristics that appear respectively depending on the thickness or overlapping of the craft molds using 3D printing technology. First, in the case of the thickness of the craft molds, the thinner the strength, the weaker the strength, but there was an advantage in that it was easier to take out the contents of the molds. However, it was determined that the thick craft molds was stable to contain the dense and heavy material. Second, in the case of overlapping of craft molds, the advantages of both thin and thick molds were obtained as a result of using a double-layered molds. However, there was a disadvantage that the surface of the contents taken out was not smooth, so that post-processing was necessary. In future research, I hope to deal with the material of the filament used in 3D printers.

• Journal of Welding and Joining
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• v.32 no.4
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• pp.10-14
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• 2014

Laser aided Direct Metal Tooling(DMT) process is a kind of Additive Manufacturing processes (or 3D-Printing processes), which is developed for using various commercial steel powders such as P20, P21, SUS420, H13, D2 and other non-ferrous metal powders, aluminum alloys, titanium alloys, copper alloys and so on. The DMT process is a versatile process which can be applied to various fields like the mold industry, the medical industry, and the defense industry. Among of them, the application of DMT process to the mold industry is one of the most attractive and practical applications since the conformal cooling channel core of injection molds can be fabricated at the slightly expensive cost by using the hybrid fabrication method of DMT technology compared to the part fabricated with the machining technology. The main objectives of this study are to provide various characteristics of the parts made by DMT process compared to the same parts machined from bulk materials and prove the performance of the injection mold equipped with the conformal cooling channel core which is fabricated by the hybrid method of DMT process.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.212-220
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• 2002

The finishing process for die and mold manufacturing is very important because it influences the final quality of products. Injection molds need higher quality surface than general purpose dies and molds. Conventional polishing can not make mold surface down to nanometer roughness efficiently because of their loading and glazing. This paper focused on the development of fixed abrasive pad using water swelling mechanism of polymer binder network. Self-conditioning was recognized as the long term polishing stabilization tool without any loading or glazing because water makes fixed abrasives free by swelling of the pad. Consequently, stable nano-polishing process has been applied on the injection mold, from the experimental results with polished surface roughness of Ra 15.1nm on STD-11 die steel.

• Design & Manufacturing
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• v.10 no.2
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• pp.6-11
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• 2016

Designed patterns of slit are introduced to the uni-directional (UD) prepreg in order to enhance the formability of the carbon/epoxy composites without wrinkling and laddering. Three different types of the slit alignment along the thickness direction are applied to analyse the deformation behavior during the compression moulding process of laminates. Degrees of the slit open and the mechanical strength are evaluated based on the level of the compaction pressure in the course of forming process. Results have shown that the mechanical strength of laminates having slits could attain at least 80% of the conventional ones without slits. However, further studies are required to identify the direct relevance of the slit alignment in laminate to the mechanical properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.188-189
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• 2021

The technology of manufacturing freeform molds with S-LOM based 3D printer has advantages in the production period and the curvature range. However, there is no any support tool about productivity analysis of S-LOM technology because S-LOM technology is early-stage technology. There can be problems about increase of construction time and cost without any decision support tool like productivity analysis models etc. Therefore, in this study, the productivity analysis simulation model for freeform formwork based on S-LOM technology was developed using ARENA software. The process and logic of manufacturing freeform molds can be easily visualized in this model. Futhermore, the resource like labor, equipment and material can be easily optimized with this model. As a result, it can contribute to preventing the increase of construction time and cost in formwork with further productivity analysis.