Yong-Gwan Im

Evaluation of micro-replication technology using silicone rubber molds and its applications

Micro-replication technology (MRT) originated in semiconductor processes and has been widely utilized in other industries such as sensors, micro-fluidics and displays. Recently, however, MRT has been slow in spreading due to its high cost and material limitations. Therefore, a new process in this paper, for MRT using silicone rubber molds is introduced. In this process, a silicone rubber mold transfers a master pattern to the final product with the same shape but different material. In order to verify the possibility of applying silicone rubber molds to MRT, its transferability was evaluated, and then was applied to the fabrication of PDP barrier ribs.

Functional prototype development : Inner visible multi-color prototype fabrication process using stereo lithography

Abstract Rapid prototyping (RP) technology has been broadly used as design, working and master models in the industrial and medical sectors since 3D systems introduced a laser lithography apparatus into the market in the name of SLA. Many RPP systems have been introduced into the market during the past 15 years. However, until now, the systems have used mainly for external physical models (mono-function), and have the basic but critical limitation of one material on one stage (mono-material). To overcome the limitations of mono-material and mono-function of conventional RP systems, the concept of functional prototype development (FPD) is newly proposed in this paper. FPD provides the necessary prototype functions such as mechanical, optical, chemical and electrical properties in order to meet broad requirements of the industry. This paper shows the representative achievements such as colored MEMS visualization model and layer interconnection visualization of electronic packaging part by way of inner visible multi-color prototyping technology.

The effects of metal filler on the characteristics of casting resin for semi-metallic soft tools

Abstract As die and mold have become more and more complicated in recent years, the demand for lowering the cost and reducing the production time becomes strong and rapid prototyping and tooling technology have been used to achieve the same. Rapid prototyping has been widely known as being able to fabricate 3D object with complex geometric shapes. RP, however, cannot be applied to real products because the required strength cannot be given by soft materials. So the RP have been copied to semi-metallic soft tools using the mixture of metal fillers and epoxy. In this paper, in order to evaluate the effect of the filler on the characteristics of semi-metallic soft tools, common aluminum powder, cast iron powder recycled by machining chips, and aluminum short fiber made by self-excited vibration technique are used. Besides, in the case of aluminum powder, the change of characteristics of semi-metallic soft tools with the volume fraction of the powder is also tested.

Rapid fabrication of aluminum shoe mold using vacuum sealed casting process

Abstract Rapid prototyping and manufacturing (RP&M) is the most appropriate technology for the small-lot production system, because the production cycle is getting shorter owing to various needs of the consumer. Recently RP products, which are made of plastics, wax, and paper, were used to examine the design of samples. These samples, however, cannot be applied to the real mold because soft materials, such as plastics lack the necessary strength to be a mold. So the materials have been changed from RP products to a metal powder filled mold like an epoxy-metal powder composite mold or metal mold, which is called rapid tooling (RT) technology. In this paper, RT technology is applied to the casting process. The casting process has the ability to reflect complicated shapes in one process. But it has not been widely used to make a die and mold because of the poor surface quality caused by air bubbles on the surface of the casting product. In this study, the porous casting mold is fabricated from a mixture of ceramic powder and water-soluble binder. The porous casting mold can improve the characteristics of aluminum casting products with the help of the vacuum sealed casting process. The vacuum sealed casting process is an advanced technology that removes the air bubbles between the porous casting mold and the liquid metal, thus making the surface of the aluminum casting product finer. The purpose of this paper is to develop a high quality shoe mold using porous casting mold and to apply the RP&M technology to the shoe industry.

Fabrication of Real 3D Shape Components Using Bi-Sn Alloys

In this paper, new replication techniques fur a metal microcomponent having a real 3D shape were introduced. Helical gear was selected as one of a real 3D microcomponents for this study. The helical gear, which was made of photo-curable resin, was fabricated as a master pattern by microstereolithography technology. Then, a silicone rubber mold was fabricated from the master pattern. Lastly, a final bismuth alloy pattern was transferred from the silicone rubber mold by the microcasting process. In this paper, the replication technique is described in detail from the master pattern to the final pattern with some investigation on factors related to the technique.

Development of Rapid Tooling Technology for Shoe Mold and Its Applications

RP&M (Rapid Prototyping and Manufacturing) is the most appropriate technology for the small-lot production system, because the production cycle is getting shorter owing to various needs of the consumer. In this paper, rapid tooling technology is applied to the casting process. The casting process has the ability to reflect complicated shapes in one process. But it has not been widely used to make a die and mold because of the poor surface quality caused by air bubbles on the surface of the casting product. In this study, the porous casting mold is fabricated from a mixture of plaster and water-soluble binder. The porous casting mold can improve the characteristics of casting products with the help of the vacuum sealed casting process. The vacuum sealed casting process is an advanced technology that removes the air bubbles between the porous casting mould and the liquid metal, thus making the surface of the casting product finer. The purpose of this paper is to develop a high quality shoe mold using porous casting mold and to apply the RP&M technology to the shoe industry.

Development of Micromolding Technology using Silicone Rubber Mold

Microsystem technology (MST) which originated from semiconductor processes has been widely spreaded into the other industry such as sensors, micro fluidics and displays. The MST, however, has been troubled in spreading with its high cost and material limitations. So, in this paper, new process for micromolding technology using silicone rubber mold was introduced. Silicone rubber mold, which was fabricated by vacuum casting, can be transferred a master pattern to a final product with the same shape but different materials. In order to verify the possibility of application of silicone rubber mold to the MST, its transferability was evaluated, and then it applied to the fabrications of polishing pad and PDP barrier ribs.