• 제목/요약/키워드: DED(Direct Energy Deposition)

검색결과 22건 처리시간 0.023초

직접식 에너지 용착 공정을 활용한 축 보수 방법 및 활용 사례 연구 (A Study on the Method and Application of Shaft Repair using Directed Energy Deposition Process)

  • 이윤선;이민규;성지현;홍명표;손용;안석;정외철;이호진
    • 한국기계가공학회지
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    • 제20권9호
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    • pp.1-10
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    • 2021
  • Recently, the repair and recycling of damaged mechanical parts via metal additive manufacturing processes have been industrial points of interest. This is because the repair and recycling of damaged mechanical parts can reduce energy and resource consumption. The directed energy deposition(DED) process has various advantages such as the possibility of selective deposition, large building space, and a small heat-affected zone. Hence, it is a suitable process for repairing damaged mechanical parts. The shaft is a core component of various mechanical systems. Although there is a high demand for the repair of the shaft, it is difficult to repair with traditional welding processes because of the thermal deformation problem. The objective of this study is to propose a repair procedure for a damaged shaft using the DED process and discuss its applications. Three types of cases, including a small shaft with a damaged surface, a medium-size shaft with a worn bearing joint, and a large shaft with serious damage, were repaired using the proposed procedure. The microstructure and hardness were examined to discuss the characteristics of the repaired component. The efficiency of the repair of the damaged shaft is also discussed.

3차원 적층 제조 공정(DED) 기반 Al-6061+Al-12Si 합금 조합 실험 (Combinatorial Experiment for Al-6061 and Al-12Si alloy Based on Directed Energy Deposition (DED) Process)

  • 전서연;박수원;송용욱;박지원;박현영;이보람;최현주
    • 한국분말재료학회지
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    • 제30권6호
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    • pp.463-469
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    • 2023
  • Aluminum alloys, known for their high strength-to-weight ratios and impressive electrical and thermal conductivities, are extensively used in numerous engineering sectors, such as aerospace, automotive, and construction. Recently, significant efforts have been made to develop novel aluminum alloys specifically tailored for additive manufacturing. These new alloys aim to provide an optimal balance between mechanical properties and thermal/electrical conductivities. In this study, nine combinatorial samples with various alloy compositions were fabricated using direct energy deposition (DED) additive manufacturing by adjusting the feeding speeds of Al6061 alloy and Al-12Si alloy powders. The effects of the alloying elements on the microstructure, electrical conductivity, and hardness were investigated. Generally, as the Si and Cu contents decreased, electrical conductivity increased and hardness decreased, exhibiting trade-off characteristics. However, electrical conductivity and hardness showed an optimal combination when the Si content was adjusted to below 4.5 wt%, which can sufficiently suppress the grain boundary segregation of the α-Si precipitates, and the Cu content was controlled to induce the formation of Al2Cu precipitates.

금속 분말의 레이저 적층 시 표면 및 단면 특성에 관한 연구 (A Study on the Characteristics of Laser Deposition Surface and Cross-section for Metal Powder)

  • 황준호;신성선;정구인;김성욱;김현덕
    • Journal of Welding and Joining
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    • 제34권4호
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    • pp.17-22
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    • 2016
  • In this study, we compared the physical and chemical properties evaluation for each size in the SUS316L metal powder produced by water atomization and gas atomization. and we analyzed the experimental data in order to find the basis of a suitable metal powder (SUS316L) for DED (Direct Energy Deposition) processing. Also it evaluated the properties of each layered surface and cross section according to the number of deposition and deposition speed. In the result of optical microscopy measurements, the metal powder by water atomization was the crack generated between the deposition layer, the deposition layer was poor quality. However, metal powder by gas atomization was obtained a relatively good deposition results than metal powder by water atomization.

레이저 용융 금속 적층 시 결함 방지를 위한 혼합 분말 적층에 관한 연구 (A Study on the Laser Melting Deposition of Mixed Metal Powders to Prevent Interfacial Cracks)

  • 심도식;이욱진;이슬비;최윤석;이기용;박상후
    • 소성∙가공
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    • 제27권1호
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    • pp.5-11
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    • 2018
  • Direct energy deposition (DED) technique uses a laser heat source to deposit a metal layer on a substrate. Many researchers have used the DED technique to study the hardfacing of molds and dies. The aim of this study is to obtain high surface hardness and a sound bonding between the AISI M4 deposits and a substrate utilizing a mixed powder that contains M4 and AISI P21 powders. To prevent interfacial cracks between the M4 deposits and the substrate, the mixed powder is pre-deposited onto a JIS S45C substrate, before the deposition of M4 powders. Interfacial defects occurring between the deposits and substrate and changes in the microhardness of the intermediate layer were examined. Observations of the cross-sections of deposited specimens revealed that the interfacial cracks appeared in samples with one and two mixed layers regardless of the mixture ratio. However, the crack was removed by increasing the mixture ratio and the number of intermediate layers. Meanwhile, the microhardness in the mixed layer was found to decrease with increasing ratio of P21 powder in the mixture and that in the upper region of the deposited layers was approximately 800 HV, which was attributed to various alloying elements in the M4 powder.

Direct energy deposition 공정을 이용한 Fe-Mn-Al-C계 저망간 경량철강 제조 (Manufacturing of Fe-Mn-Al-C Based Low Mn Lightweight Steel Via Direct Energy Deposition)

  • 고광규;손한솔;정차희;배효주;박은혜;김정기;최현주;설재복
    • 한국분말재료학회지
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    • 제29권4호
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    • pp.320-324
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    • 2022
  • Lightweight steel is a crucial material that is being actively studied because of increased carbon emissions, tightening regulations regarding fuel efficiency, and the emergence of UAM, all of which have been recently labeled as global issues. Hence, new strategies concerning the thickness and size reduction of steel are required. In this study, we manufacture lightweight steel of the Fe-Mn-Al-C system, which has been recently studied using the DED process. By using 2.8 wt.% low-Mn lightweight steel, we attempt to solve the challenge of joining steel parts with a large amount of Mn. Among the various process variables, the laser scan power is set at 600 and 800 W, and the laser scan speed is fixed at 16.67 mm/s before the experiments. Several pores and cracks are observed under both conditions, and negligibly small pores of approximately 0.5 ㎛ are observed.

PBF와 DED 공정으로 제조된 17-4PH 스테인리스 강의 미세조직 및 기계적 특성 평가 (Evaluation of Microstructure and Mechanical Properties in 17-4PH Stainless Steels Fabricated by PBF and DED Processes)

  • 윤종천;이민규;최창영;김동혁;정명식;최용진;김다혜
    • 한국기계가공학회지
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    • 제17권2호
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    • pp.83-88
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    • 2018
  • Additive manufacturing (AM) technologies have attracted wide attention as key technologies for the next industrial revolution. Among AM technologies using various materials, powder bed fusion (PBF) processes and direct energy deposition (DED) are representative of the metal 3-D printing process. Both of these processes have a common feature that the laser is used as a heat source to fabricate the 3-D shape through melting of the metal powder and solidification. However, the material properties of the deposited metals differ when produced by different process conditions and methods. 17-4 precipitation-hardening stainless steel (17-4PH SS) is widely used in the field of aircraft, chemical, and nuclear industries because of its good mechanical properties and excellent corrosion resistance. In this study, we investigated the differences in microstructure and mechanical properties of deposited 17-4PH SS by PBF and DED processes, including the heat treatment effect.

레이저 빔 직경 변화에 따른 17-4 PH 스테인리스 강 DED 적층 조형체의 미세조직 및 경도 변화 (Effect of Laser Beam Diameter on the Microstructure and Hardness of 17-4 PH Stainless Steel Additively Manufactured by Direct Energy Deposition)

  • 김우혁;고의준;김정한
    • 한국분말재료학회지
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    • 제29권4호
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    • pp.314-319
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    • 2022
  • The effect of the laser beam diameter on the microstructure and hardness of 17-4 PH stainless steel manufactured via the directed energy deposition process is investigated. The pore size and area fraction are much lower using a laser beam diameter of 1.0 mm compared with those observed using a laser beam diameter of 1.8 mm. Additionally, using a relatively larger beam diameter results in pores in the form of incomplete melting. Martensite and retained austenite are observed under both conditions. A smaller width of the weld track and overlapping area are observed in the sample fabricated with a 1.0 mm beam diameter. This difference appears to be mainly caused by the energy density based on the variation in the beam diameter. The sample prepared with a beam diameter of 1.0 mm had a higher hardness near the substrate than that prepared with a 1.8 mm beam diameter, which may be influenced by the degree of melt mixing between the 17-4 PH metal powder and carbon steel substrate.

3차원 금속 프린팅 공정에서의 조형파트 진단 및 조형공구경로 검증 (Verification of Build Part and Tool Paths for Metal 3-D Printing Process)

  • 이규복;지해성
    • 대한기계학회논문집A
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    • 제41권2호
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    • pp.103-109
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    • 2017
  • AMM(Additive Metal Manufacturing)이라 호칭되는 3차원 금속 프린팅(metal 3-D printing) 공정은 금속분말(metal powder)을 적층 재료로 사용하여 기계적부품용 실형상 금속 파트(metallic parts)를 직접 조형하여 제조한다. 한편, 조형 파트형상의 STL모델에 존재하는 기하학적 오류들과 특징형상들의 특이성으로 인하여 조형 작업 중에 내부에 결함들이 포함된 실형상 파트가 조형될 가능성이 존재하게 되며 이로 인해 3차원 금속 프린팅 조형공정 자체의 신뢰성에 문제를 야기할 수 있다. 본 논문에서는 이러한 조형작업 중 발생할 수 있는 결함들을 미리 진단, 분석하고 수정하기 위하여 첫째, 조형 전에 STL 형상모델의 진단분석을 통하여 결함요소를 사전에 탐지하고 둘째, 적층 단면내 조형 공구 경로상에 실제로 포함된 결함들을 분석하고 이를 수정하기 위한 조형 파트 진단 및 조형 공구 경로 검증 연구방법을 제시하였다. 또한 DED(direct energy deposition) 공정을 기준으로 2가지 STL 형상파트 사례들에 대하여 제시한 연구방법의 case study를 수행하였다.

Ti-6Al-4V 합금 기지 위에 FGM 방식으로 적층제조 된 Inconel 718의 접합 특성 분석 (Joint Properties of Inconel 718 Additive Manufactured on Ti-6Al-4V by FGM method)

  • 박찬웅;박진웅;정기채;이세환;김성훈;김정한
    • 한국분말재료학회지
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    • 제28권5호
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    • pp.417-422
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    • 2021
  • In the present work, Inconel 718 alloy is additively manufactured on the Ti-6Al-4V alloy, and a functionally graded material is built between Inconel 718 and Ti-6Al-4V alloys. The vanadium interlayer is applied to prevent the formation of detrimental intermetallic compounds between Ti-6Al-4V and Inconel 718 by direct joining. The additive manufacturing of Inconel 718 alloy is performed by changing the laser power and scan speed. The microstructures of the joint interface are characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and micro X-ray diffraction. Additive manufacturing is successfully performed by changing the energy input. The micro Vickers hardness of the additive manufactured Inconel 718 dramatically increased owing to the presence of the Cr-oxide phase, which is formed by the difference in energy input.

Trends in Materials Modeling and Computation for Metal Additive Manufacturing

  • Seoyeon Jeon;Hyunjoo Choi
    • 한국분말재료학회지
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    • 제31권3호
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    • pp.213-219
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    • 2024
  • Additive Manufacturing (AM) is a process that fabricates products by manufacturing materials according to a three-dimensional model. It has recently gained attention due to its environmental advantages, including reduced energy consumption and high material utilization rates. However, controlling defects such as melting issues and residual stress, which can occur during metal additive manufacturing, poses a challenge. The trial-and-error verification of these defects is both time-consuming and costly. Consequently, efforts have been made to develop phenomenological models that understand the influence of process variables on defects, and mechanical/ electrical/thermal properties of geometrically complex products. This paper introduces modeling techniques that can simulate the powder additive manufacturing process. The focus is on representative metal additive manufacturing processes such as Powder Bed Fusion (PBF), Direct Energy Deposition (DED), and Binder Jetting (BJ) method. To calculate thermal-stress history and the resulting deformations, modeling techniques based on Finite Element Method (FEM) are generally utilized. For simulating the movements and packing behavior of powders during powder classification, modeling techniques based on Discrete Element Method (DEM) are employed. Additionally, to simulate sintering and microstructural changes, techniques such as Monte Carlo (MC), Molecular Dynamics (MD), and Phase Field Modeling (PFM) are predominantly used.