The number of freeform buildings has been continuously increasing, serving as a landmark representing a country or a city. However, most of the freeform buildings have been built with conventional construction methods and required a tremendous amount of construction cost. This study seeks to apply additive manufacturing technologies to the freeform concrete formwork. Among many additive manufacturing techniques, the study focuses on the Laminated Object Manufacturing (LOM) method because of its advantages on building speed and cost. Also, the LOM technique is modified by using sloped angle at the side surface of the laminated layer (called Sloped-LOM or S-LOM), which yields great increase in the accuracy. We built a new FreeForm Formwork 3D Printer (named F3D printer) using the new approach. The F3D printer consists of a 5-axis laser cutting device for sloped cutting of EPS (Expanded Poly-Styrene) sheets with high speed, an auto pallet changer for EPS feeding, and a palletizer for EPS loading. This paper introduces the S-LOM method and the F3D printer, and the comparisons of the outputs from the conventional method and S-LOM method through actual formwork production.
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Optimization Design of Student KSAE BAJA Knuckle Using SLM 3D Printer Young Woo Im, Geon Taek Kim, Hyeon Sang Shin, Kang Min Kim, Bu Hyun Shin, Jong Won Lee, Jinsung Rho Journal of the Korean Society for Precision Engineering.2023; 40(9): 719. CrossRef
Development of Connection Technology between Multi-Point Press and Flexible Mold for Manufacturing Free-Form Concrete Panel Jiyeong Yun, Jongyoung Youn, Jihye Kim, Donghoon Lee Buildings.2022; 12(6): 767. CrossRef
Development of an Adaptive Slicing Algorithm of Laminated Object Manufacturing Based 3D Printing for Freeform Formwork Dongyoun Lee, Junho Hong Buildings.2022; 12(9): 1335. CrossRef
Optimal slope cutting algorithm for EPS free-form formwork manufacturing Harim Kim, Heejae Ahn, Chanwoo Kim, Dongyoun Lee, Taehoon Kim, Yeonho Ko, Hunhee Cho Automation in Construction.2022; 143: 104527. CrossRef
Seismic Performance of F3D Free-Form Structures Using Small-Scale Shaking Table Tests Min Jae Park, Gain Cheon, Robel Wondimu Alemayehu, Young K. Ju Materials.2022; 15(8): 2868. CrossRef
An Analytical Study of the Latest Trends of Free-Form Molds Jongyoung Youn, Jiyoung Yun, Sungjin Kim, Bumjin Han, Sunglok Do, Donghoon Lee Sustainability.2022; 14(5): 3084. CrossRef
Development of Side Mold Control Equipment for Producing Free-Form Concrete Panels Jiyeong Yun, Kyeongtae Jeong, Jongyoung Youn, Donghoon Lee Buildings.2021; 11(4): 175. CrossRef
When a building explodes, debris generated bounces after hitting the ground with high energy. It is called the ricochet phenomenon. Ricochet phenomena increase the risk of damage by increasing the moving distance of the debris. The ricochet of debris is impacted by the type of medium. In this paper, the behavior and travel distance of debris after ricocheting are studied according to the type of medium. For various initial conditions, the ricochet of the debris was studied through FEM, and the resulting values were fitted to the 3D curved surface, to predict the speed and angle after the ricochet. The trajectory of the sphere was calculated with the flight formula, considering drag force by using the MATLAB. The ricochet of debris is impacted by the contact area with the medium. As the contact area increases, the reflection angle increases due to the increase of the repulsive force. As the size of the debris increases, the contact area increases and the energy loss increases, but it moves further because of the increase of the weight and kinetic energy. The type of media around the building can be used as an appropriate means of controlling the travel distance of the debris.
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A Study of Moving Distance of Ricocheted Debris for Various Debris Shape with Air Drag Coefficient Yoon Keon Kim, Woo Chun Choi Journal of the Korean Society for Precision Engineering.2020; 37(3): 209. CrossRef
We used a construction method using a CNC milling machine, where free-formed molds were made by cutting EPS (Expanded PolyStyrene) foam with the CNC machine, to build free-formed buildings. CNC milling is off-the-shelf technology that can easily cut EPS foam; however its production cost is too high and the time to manufacture an EPS mold is too long. This paper proposes a novel cutting machine with a fast and cost effective mechanism to manufacture EPS concrete molds. Our machine comprises a cutter and Cartesian coordinate type moving mechanism, where the cutter cuts EPS foam using a hotwire in the shape of ‘Π’ and is capable of adjusting its cutting angle in real-time while keeping its cutting width. We proved through cutting experiments on the CNC machine that cutting time was greatly shortened compared to the conventional method and that the resulting concrete mold satisfied manufacturing precision.
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Citations to this article as recorded by
Development of Side Mold Control Equipment for Producing Free-Form Concrete Panels Jiyeong Yun, Kyeongtae Jeong, Jongyoung Youn, Donghoon Lee Buildings.2021; 11(4): 175. CrossRef
Manufacturing Automation System of Freeform Concrete Formwork Using S-LOM Method Joonhyeok Sim, Hakmin Kim, Kyunwoo Park, Chanwoo Kim, Daehie Hong Journal of the Korean Society for Precision Engineering.2020; 37(1): 43. CrossRef
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