Micro hot-embossing is a powerful tool in the agile additive manufacturing industry. Its applications include optical components, micro-fluidic devices, MEMS, hydrophobic/hydrophilic surfaces, and energy harvesting devices. To overcome a drawback of low-process speed, the R2R process has been innovated, with novel embossing mechanisms and process optimization. Also, new materials beyond thermoplastic polymers have been applied to develop new devices, or enhance device performance. This review surveys recent progress in micro hot-embossing technology, in terms of new mold fabrication process, process innovation, and various applications.
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Manufacturing Process for Highly Stable Thermal Imprinting Transparent Electrode Using IPL Sintering Yunseok Jang Journal of the Korean Society for Precision Engineering.2025; 42(1): 75. CrossRef
Finding Ways to Deform Fine Patterns Fabricated by UV Curable Resin Woo Young Kim, Su Hyun Choi, Seonjun Kim, Young Tae Cho Journal of the Korean Society for Precision Engineering.2020; 37(4): 291. CrossRef
This study presents a transparent-patch antenna using a silver-mesh transparent electrode film with a high optical transmittance (87.7%), low haze (1.1%), and low sheet resistance (8.9 Ω/sq). The silver-mesh transparent electrode film is fabricated by using UV embossing and doctor blading without any high-temperature or vacuum processes. The UV resin pattern is transferred from a nickel mold to a plastic film, and then a silver paste is filled into the UV resin pattern. The transparent antenna patch and ground plane are obtained by repeating these processes on both sides of a single plastic film. The antenna patch is designed with a width of 44.8 mm and a height of 36.0 mm in order to obtain a resonant frequency at 2.45 GHz, which is a frequency of wireless LAN. As a result, the transparent-patch antenna has a reflection coefficient (S11 parameter) of -35.6 dB, a peak gain of -3.99 dBi, and a radiation efficiency of 6.2% at 2.45 GHz. Finally, a Wi-Fi router using the transparent-patch antenna is demonstrated.
Generally speaking, the high speed forming process is suitable for the precise manufacturing of hard-to-form and high strength materials. This study conducted microscale embossing and punching experiments by establishing a forming system that uses a laser induced acceleration. The changes in the flyer velocity with the laser energy, flyer thickness, and flyer diameter were measured using a high speed camera, and the effects of the noted acceleration characteristics of flyers on processing performance were investigated. It is particularly important that in the case of punching, the advantages of high speed processing, in which the accuracy was improved by increasing the shear zone of the workpiece, were identified. Significantly in the case of embossing, it was observed that the formability improved by increasing the flyer velocity as the flyer diameter decreased. However, in the case when the flyer thickness was decreased, increased energy was consumed in the plastic deformation of the flyer, and the advantages of high speed forming could not be realized. For this reason, further research is needed to take advantage and optimize the forming process using the laser induced acceleration through experiments which are noted as considering the various process variables and materials.
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Performance evaluation of laser shock micro-patterning process on aluminum surface with various process parameters and loading schemes Dae Cheol Choi, Hong Seok Kim Optics and Lasers in Engineering.2020; 124: 105799. CrossRef
In this paper, we propose a simple and low-cost fabrication method for PMMA (Poly (Methyl Methacrylate)) acoustophoretic microfluidic chips using plasma-assisted bonding followed by MEMS (Microelectromechanical Systems) processes. A metal mold for replicating the PMMA polymer was fabricated using MEMS processes, and the microfluidic channel was imprinted on the PMMA polymer using a hot-embossing process. The closed fabricated microfluidic channel was achieved by means of the plasma-assisted bonding between the PMMA channel and the flat PMMA cover. The plasma treatment and hot-embossing conditions for PMMA-PMMA bonding were studied and evaluated. The particle separation test confirmed that the PMMA acoustophoretic microfluidic chips could be used. We expect the Si-based acoustophoretic microfluidic chip to be replaced by the presented polymer chip in such applications as blood or droplet separation.
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Fabrication of Acoustophoretic Device with Lateral Polymer Wall for Micro-Particle Separation Sungdong Kim, Su Jin Ji, Song-I Han, Arum Han, Young Hak Cho Journal of the Korean Society for Precision Engineering.2022; 39(5): 379. CrossRef
Microfluidic Chip Fabrication of Fused Silica Using Microgrinding Pyeong An Lee, Ui Seok Lee, Dae Bo Sim, Bo Hyun Kim Micromachines.2022; 14(1): 96. CrossRef
PMMA Thermal Bonding System Using Boiling Point Control Dong Jin Park, Taehyun Park Journal of the Korean Society for Precision Engineering.2021; 38(8): 613. CrossRef
Microchannel Fabrication on Glass Materials for Microfluidic Devices Jihong Hwang, Young Hak Cho, Min Soo Park, Bo Hyun Kim International Journal of Precision Engineering and Manufacturing.2019; 20(3): 479. CrossRef
Hot embossing techniques are used to engrave patterns on plastic substrates. Roll based hot embossing uses a heated roll for a continuous process. A heated roll with relief patterns is impressed on a preheated plastic substrate. Then, the substrate is cooled down quickly to prevent thermal shrinkage. The roll speed is normally very slow to ensure substrate temperature increase up to the glass transition temperature. In this paper, we propose a noncontact preheating technique using focused infrared light. The infrared light is focused as a line beam on a plastic substrate using an elliptical mirror just before entering the hot embossing roll. The mid range infrared light efficiently raises the substrate temperature. For preliminary tests, substrate deformation and temperature changes were monitored according to substrate speed. The experiments show that the proposed technique is a good possibility for high speed hot embossing.
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Manufacturing Process for Highly Stable Thermal Imprinting Transparent Electrode Using IPL Sintering Yunseok Jang Journal of the Korean Society for Precision Engineering.2025; 42(1): 75. CrossRef
Study of a Line‐Patterning Process Using Impact Print‐Type Hot Embossing Technology Myeongjin Kim, Jaewon Ahn, Junseong Bae, Donghyun Kim, Jongbum Kim, Jonghyun Kim, Dongwon Yun Advanced Engineering Materials.2020;[Epub] CrossRef
Variation of a Triangular Pattern Shape due to Shrinkage in the Repeated UV Imprint Process Jiyun Jeong, Su Hyun Choi, Young Tae Cho Journal of the Korean Society of Manufacturing Process Engineers.2020; 19(7): 67. CrossRef
Recent Research Trend of Micro Hot-Embossing Seung-Hyun Lee, Jeongdai Jo, Kwang-Young Kim, Young-Man Choi Journal of the Korean Society for Precision Engineering.2018; 35(11): 1027. CrossRef
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