• 한국산업융합학회 논문집
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• 제27권2_2호
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• pp.415-424
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• 2024

This study analyzes trends and characteristics of the machine tool remanufacturing industry and proposes a standard process that considers environmental impact assessment during the remanufacturing process. First, trends in remanufacturing and environmental regulations are reviewed. And the current status of the machine tool remanufacturing industry and cases of national R&D projects related to machine tools are analyzed. Machine tool remanufacturing has a high resource saving effect, and remanufacturing is carried out as a finished product rather than as a part. And the scope of remanufacturing work is very wide due to the performance improvement of the machine and the addition of features. In order for the machine tool remanufacturing industry to be competitive, it is necessary to create products with high added value. In addition, in order to respond to international environmental regulations, it is necessary to secure related data by conducting an environmental impact assessment together during remanufacturing.

• 소성∙가공
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• 제33권4호
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• pp.277-284
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• 2024

Interest in remanufacturing of part has significantly increased to reduce used material and energy together. The directed energy deposition (DED) process has widely applied to remanufacturing of the part. An excessive residual stress takes place in the vicinity of the deposited region by the DED process due to rapid heating and rapid cooling (RHRC) phenomenon. The excessive residual stress decreases the reliability of the remanufactured part. Therefore, thermo-mechanical analysis for the remanufacturing of the part is needed to investigate heat transfer and residual stress characteristics in the vicinity of the deposited region. The thermo-mechanical analysis of a large volume deposition is significantly difficult to perform due to the requirement of a long computation time and a large computer memory. The goal of this paper is to investigate thermo-mechanical characteristics for remanufacturing of the ATC part using a DED process. The methodology of the thermo-mechanical analysis for a large volume deposition is proposed. From the results of analysis, heat transfer and residual stress characteristics during deposition and cooling stages are investigated. In addition, the proper deposition strategy from the viewpoint of the residual stress is discussed.

• 청정기술
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• 제19권2호
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• pp.173-183
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• 2013

전 세계적으로 자원순환 효율성 증대 및 에너지 절감을 위해 친환경제품 설계, 재활용, 재제조 등 다양한 방법론이 제시되고 있다. 본 논문은 하나의 방안으로 유니소재화에 대해서 제시하고 있다. 유니소재화는 제품 재활용이 용이하고 유해물질 사용을 저감하기 위해 설계, 생산, 수거, 재활용 등을 고려한 기존 제품의 소재의 단일화(단순화)로 정의한다. 본 연구에서는 적용 가능한 유니소재화 대상제품을 평가할 수 있는 정성적, 정량적 평가 항목을 개발하였다. 평가항목은 경제성, 기술성, 환경성을 고려하여 총 9가지로 구성되어 있으며 평가항목을 적용하여 4가지 대상제품에 대해 사례를 연구했다. 연구 결과, 블라인드형 창문을 제외한 3가지 대상제품은 유니소재화 제품으로 적용이 가능하며 평가항목의 객관성을 높이기 위해서는 유니소재화의 개념을 구체화하고 산업별 특성을 고려하여 평가할 필요가 있다.

• 산업경영시스템학회지
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• 제35권3호
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• pp.77-86
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• 2012

We consider the capacitated lot-sizing and scheduling problem for a paper remanufacturing system that produces several types of corrugated cardboards. The problem is to determine the lot sizes as well as the sequence of lots for the objective of minimizing the sum of setup and inventory holding costs while satisfying the demand and the machine capacity over a given planning horizon. In particular, the paper remanufacturing system has sequence-dependent setup costs that depend on the type of product just completed and on the product to be processed. Also, the setup state at one period can be carried over to the next period. An integer programming model is presented to describe the problem. Due to the complexity of the problem, we modify the existing two-stage heuristics in which an initial solution is obtained and then it is improved using a multi-pass interchange method. To show the performances of the heuristics, computational experiments were done using the real data, and a significant amount of improvement is reported.

• Tribology and Lubricants
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• 제30권6호
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• pp.350-355
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• 2014

This study proposes a sustainable bearing remanufacturing process using the ultrasonic nanocrystal surface modification (UNSM) technique. The UNSM technique is a newly developed and sophisticated surface modification technique that can increase the mechanical properties and improve the friction and wear performance of materials. Taking advantage of the bearing manufacturing process is the most significant way of optimizing the life of a bearing. The proper maintenance and usage of repaired bearings can increase their life to be equal to or greater than that of new bearings. This paper discusses the restoration of certain mechanical properties of worn, damaged, and discarded bearings, and suggests a remanufacturing process for used bearings, which can impart them with a lifespan equivalent to that of new bearings. The most damaged part of the discarded bearings is the raceway, which is the site of accumulated fatigue. The existing polishing or barrel finishing processes can recover the accumulated fatigue only partially. Rolling contact fatigue tests performed on UNSM-treated new and used specimens polished after $4{\times}10^6$ cycles reveal that UNSM-treated new specimens exhibit the longest fatigue life compared to other specimens. This study verifies the proposed complete fatigue recovery process, which can increase the fatigue life of used bearings to a level greater than that of new bearings.

• 한국재료학회지
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• 제29권11호
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• pp.697-702
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• 2019

In this study, using a wet chemical process, we evaluate the effectiveness of different solution concentrations in removing layers from a solar cell, which is necessary for recovery of high-purity silicon. A 4-step wet etching process is applied to a 6-inch back surface field(BSF) solar cell. The metal electrode is removed in the first and second steps of the process, and the anti-reflection coating(ARC) is removed in the third step. In the fourth step, high purity silicon is recovered by simultaneously removing the emitter and the BSF layer from the solar cell. It is confirmed by inductively coupled plasma mass spectroscopy(ICP-MS) and secondary ion mass spectroscopy(SIMS) analyses that the effectiveness of layer removal increases with increasing chemical concentrations. The purity of silicon recovered through the process, using the optimal concentration for each process, is analyzed using inductively coupled plasma atomic emission spectroscopy(ICP-AES). In addition, the silicon wafer is recovered through optimum etching conditions for silicon recovery, and the solar cell is remanufactured using this recovered silicon wafer. The efficiency of the remanufactured solar cell is very similar to that of a commercial wafer-based solar cell, and sufficient for use in the PV industry.

• 한국융합학회논문지
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• 제12권7호
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• pp.159-167
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• 2021

자원 고갈, 생태 파괴 등 날로 심각해지는 환경문제와 지속가능한 패션에 대한 소비자들의 관심은 패션 산업 사슬을 녹색 에너지 절약 방향으로 발전하게 하였다. 본 연구는 특정 집단의 지속가능한 패션 소비에 대한 태도와 심리를 탐구하고 재생 방직품 또는 재제조 의류 원단에 대한 그들의 구체적 인식과 태도를 탐구하는데 취지를 두었다. 본문은 구제 의류의 특성이 소비자에 미치는 영향에 대해 알아보았다. 관련 문헌자료를 찾아본 기초에서 소비자에 영향을 주는 일련의 결정적 요소와 재생품의 표현 가치, 사회적 가치 등 특징을 확정했다. 이 이론적 배경에 근거해 온라인 설문조사를 설계했으며 총 226개의 유효 응답을 받았다. 조사 결과에 따르면 사회적 가치와 환경보호에 대한 중시가 소비자의 결정에 영향을 미치는 것으로 나타났다. 이상 연구 결과는 전체 녹색 환경보호와 생태 의류 회수 산업 체계의 연구에 도움이 되며 의류 산업의 지속가능한 발전을 추진한다.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.1119-1125
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• 2022

The depletion of resources and waste disposal caused by the continuous development of industry have emphasized the need to reduce consumption and production, recycle and reuse, and the importance of remanufacturing has increased in recent years. The spindle part of the aging planner miller, which is currently being remanufactured, is one of the factors that has the greatest impact on the performance of the machine tool. When designing the spindle part of the spindle shaft, there are considerations such as the configuration size bearing performance of the main shaft, but the diameter of the main shaft, the dangerous speed bearing, and the arrangement that affect the machining accuracy should be basically considered. As such, various studies have been conducted on the design of machine tool spindle spindles, but research on the reverse engineering of existing aging machine tool spindle spindles is poor. Reverse engineering is designing in the direction of improving performance by extracting specifications from already finished products, and first scanning the reverse engineered object through a 3D scanner, 3D modeling is performed based on the collected data, and then the process of deriving improvement plans by reverberating to improve performance by identifying wear and damage conditions is followed. Therefore, in this study, the purpose of this study is to provide data on reverse engineering by deriving improvement plans through optimal design for the bearing position of the aging planar Miller spindle spindle using central composite programming.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.1097-1102
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• 2022

With the continuous development of the current industry, the current global environment is in a very serious situation, with resource supply and demand dependent on imports and huge costs for waste disposal due to the depletion of resources and mass generation of industrial waste. Its limitations have already been revealed in many fields, and the importance of re-manufacturing is drawing attention as a countermeasure to these problems. Re-manufacturing aims to recover products that are in the aging and disposal stages, recover to performance close to new products, and re-commercialize them. Among them, most of the machine tools are made of materials such as steel and cast iron with large structures, and raw materials are widely used when producing new products. In addition, since a lot of carbon is generated due to production, it is an object that can obtain a great re-manufacturing effect. Planner millers belonging to large machine tools are one of the machine tool equipment that can greatly reduce resources and energy through re-manufacturing because the structure is very large and the casting is several to tens of tons. Through this machine tool, performance tests and results are derived on the development of re-manufacturing source technology and domestic servo motor and CNC control device.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.1103-1110
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• 2022

The old machine tools that have been used for a long time cause both increase in defective rate and decrease in productivity compared to new machines due to wear and failure of their components. In order to improve productivity and quality of machined components through remanufacturing, it is necessary to analyze the wear and failure of major components of old machine tools. In this study, the process for reverse engineering is designed for the remanufacture of planner millers, which belong to a very large machine tool. Also, the suitability of the designed process is verified through the analysis of the selected remanufactured components. In the first step of the process, some major components of the aging planner miller are scanned using a 3D laser scanner. In the next step, reverse engineering is performed using the data obtained through 3D scanning. Finally, wear and failure analysis is performed by comparing the reverse engineering data with the scan data. As a result, this reverse design and wear analysis can complement the insufficient design database and reduce costs in the maintenance of remanufactured products.