CAE를 이용한 초음파 나이프 트랜스듀서 설계

송기혁,김혜진,성시명,홍서연 한국생산제조학회 2023 한국생산제조학회지 Vol.32 No.5

This study aimed to design and verify ultrasonic knife modules, which have experienced a recent surge in demand. To this end, ultrasonic transducers and horns with longitudinal vibration characteristics of 40 kHz grounded in theoretical equations were designed. Subsequently, tensile experiments on materials were conducted and applied for precise wavelength analysis. Modal and harmonic response analysis using CAE was performed to predict vibration characteristics and natural frequencies for the designed ultrasonic knife. As a result of the analysis, the study revealed that the knife had an intrinsic frequency characteristic of about 38.1 kHz and vibrated in the axial direction. An ultrasonic knife, stemming from these findings, was manufactured and confirmed to achieve equivalent performance to the design, through resonance frequency analysis and vibration mode analysis.

CFRTP 소재 가공을 위한 초음파 나이프 적용 가능성에 관한 연구

송기혁,김혜진,박지영,성시명 한국금형공학회 2023 한국금형공학회지 Vol.17 No.2

In this study, an experiment was conducted to confirm the applicability of the external shape control of the ultrasonic knife to the CFRTP material, which is the base material of thermoplastic. TC910 based on polyamide6 (PA6) was used as the material. The slope 와 and tool transfer speed of the material and tool were selected as process factors for processing, and the following results were obtained. Under all cutting conditions using an ultrasonic knife, friction heat caused by high-frequency vibration was issued at 150℃ at the contact part between the material and the knife during cutting. As a result of the cutting force analysis, the faster the transfer speed, the higher the cutting force as the angle of entry of the blade increased, and the size of the cutting force changed during cutting. As for the size of the burr in accordance with the transfer speed condition, the smallest burr occurred at 150mm/min in the side part, and the smallest burr occurred at 150mm/min and 200mm/min in the case of the outlet burr. The size of the burr according to the entry angle tended to decrease as the tool entry angle increased, and the side part tended to increase as the tool entry angle increased. As a result of the cutting surface analysis, it was confirmed that the base material was eluted under all conditions, and the faster the transfer speed, the lower the elution phenomenon of the base material. Based on the above results, cutting the CFRTP material with an ultrasonic knife is possible, but the effect on heat generation caused by friction needs to be minimized, and further research needs to be conducted on this.

극저온 가스와 MQL(minimum quantity lubrication)의 복합 분사를 위한 하이브리드 노즐 설계에 관한 전산유체역학 해석

송기혁,신봉철,윤길상,하석재 한국금형공학회 2019 한국금형공학회지 Vol.13 No.3

In conventional machining, the use of cutting fluid is essential to reduce cutting heat and to improve machining quality. However, to increase the performance of cutting fluids, various chemical components have been added. However, these chemical components during machining have a negative impact on the health of workers and cutting environment. In current machining, environment-friendly machining is conducted using MQL (minimum quantity lubrication) or cryogenic air spraying to minimize the harmful effects. In this study, the injection nozzle that can combined injecting minimum quantity lubrication(MQL) and cryogenic gas was designed and the shape optimization was performed by using computational fluid dynamics(CFD) and design of experiment(DOE). Performance verification was performed for the designed nozzle. The diameter of the sprayed fluid at a distance of 30 mm from the nozzle was analyzed to be 21 mm. It was also analyzed to lower the aerosol temperature to about 260~270K.

장중첩증을 일으킨 공장의 염증성 가성종양: 증례 보고

송기혁,김유미 대한영상의학회 2004 대한영상의학회지 Vol.51 No.5

염증성 가성종양은 병인이 불명확한 종양과 유사한 양성질환으로 폐에서 가장 많이 보고 되 었으며, 위장관에서의 발생은 드물게 보고 되어 있다. 위장관에서 발생시 장중첩증에 의한 장 폐색을 일으키거나 방사선 검사나 선별내시경 검사에서 증상 없이 우연히 발견되기도 한다. 저자들은 수술로 확진된 공장에서 발생한 염증성 가성종양에 의해 장중첩증을 일으킨 1예를 보고하고자 한다. Inflammatory pseudotumors are tumor-like, benign lesions of uncertain pathogenesis and have most commonly been reported in the lungs. They occur rarely in the gastrointestinal tract and may cause small bowel obstruction due to intussusception or, less commonly, as an incidental finding on radiologic examination or screening endoscopy. We present a case of surgically proven jejunal intussusception caused by inflammatory pseudotumor.

조선기독교에씬센돏프가나기를고대함

송기혁 신학지남사 1929 신학지남 Vol.11 No.2

루프검지기 적정 매설깊이 및 휘더선 한계길이 연구

송기혁,오영태 한국ITS학회 2004 한국ITS학회 학술대회 Vol.2004 No.1

흡입 손상의 만성 합병증: 반응성 기도과민 증후군에 대한 HRCT 소견과 폐기능 검사와의 상관관계

송기혁,이인선,정은희,지영구,이영석 대한영상의학회 2007 대한영상의학회지 Vol.57 No.3

목적: 흡입 손상을 입은 후 만성적 기침과 호흡곤란, 폐기능 검사상 이상 소견을 보이는 환자는 대부분 반응성 기도과민 증후군이다. 그러나 지금까지 이러한 환자군의 영상소견에 대한 연구는 거의 없었다. 이에 반응성 기도과민 증후군 환자의 단순 X선 사진과 HRCT 소견에 대하여 알아보고, HRCT 소견과 폐기능 검사 간의 연관성을 분석하였다. 대상과 방법: 2003년 3월 천안 인근 초등학교 축구부 기숙사에서 발생한 화재에 노출된 9명이 8개월 후 만성적 기침, 운동 중 호흡곤란으로 내원하였다. 이 중 8명은 단순 X선 사진과 HRCT, 폐기능 검사를 시행하였고, 증상이 심한 2명은 1년 후 추적검사를 시행하였다. 2명의 영상의학과 의사가 단순 흉부 X선 사진과 HRCT 를 후향적 분석하였고, 폐기능 검사와의 연관성을 분석하였다. 결과: 폐기능 검사상 8명 중 6명이 반응성 기도 과민 증후군으로 진단받았다. 8명 모두 단순 X선 사진에서 정상 소견을 보였으나, 4명은 HRCT 상 이상소견을 보였다. 이상소견으로 모자이크양 공기 폐색(n=4), 기관지벽 비후(n=1), 폐실질 경화(n=1)를 보였다. HRCT 상 이상 소견을 보인 4명은 모두 반응성 기도과민 증후군으로 진단받았다. 추적검사를 한 2명은 임상 증상 및 폐기능 검사에서 호전되었고, HRCT 역시 호전된 양상을 보였다. 결론: 반응성 기도과민 증후군에 있어 HRCT 는 폐실질 및 기관지 병변의 손상 여부와 병변의 범위를 파악하는 데 필요하며, 정확한 진단을 위해서는 최대 흡기말과 최대 호기말 스캔을 둘다 얻어야 한다. Purpose: To evaluate the HRCT findings and to correlate the findings with the results of a pulmonary function test (PFT) in patients with reactive airway dysfunction syndrome (RADS). Materials and Methods: On March 2003, a fire at a boarding house of primary school soccer players caused a multiple casualty disaster. After 8 months, nine boys that presented with chronic cough and dyspnea were treated, and were subjected to follow-up evaluations. Eight patients underwent a chest radiograph, HRCT, and a PFT. Two patients with severe symptoms received extended follow-up after 1 year. Two radiologists retrospectively reviewed the chest radiographs and the follow-up HRCT scans. We correlated the HRCT findings with the results of the PFT. Results: Six patients with an inhalation injury were diagnosed with RADS. On the chest radiographs, eight patients showed no abnormal findings. On an HRCT scan, four patients showed abnormal findings. The abnormal findings were mosaic air trapping (n = 4), bronchial wall thickening (n = 1), and parenchymal consolidation (n = 1). In all four patients that showed abnormal findings in the HRCT scan, abnormal results of the PFT were also seen. The two patients that received extended follow-up showed an improvement of the clinical symptoms, as seen by the PFT, and had a decreased extent and degree of mosaic air trapping, as seen on HRCT. Conclusion: An HRCT scan is an essential modality for the diagnosis and follow-up of patients with RADS. Both a full expiratory and inspiratory HRCT scan must be performed for an accurate diagnosis.

가변식 중앙버스전용차로제 효율성 분석

송기혁,심운섭,오영태 한국ITS학회 2004 한국ITS학회 학술대회 Vol.2004 No.1

CAE 를 활용한 덴탈 임플란트 부품 자동 포장 검사 시스템에 대한 구조적 안전성 분석

송기혁(K. H. Song),성시명(S. M. Sung),김선삼(S. Kim) Korean Society for Precision Engineering 2022 한국정밀공학회 학술발표대회 논문집 Vol.2022 No.5

LED 칩 제조용 사파이어 웨이퍼 절단을 위한 내부 레이저 스크라이빙 가공 특성 분석

송기혁(Song, Ki-Hyeok),조용규(Cho, Yong-Kyu),김병찬(Kim, Byung-Chan),강동성(Kang, Dong-Seong),조명우(Cho, Meyong-Woo),김종수(Kim, Jong-Soo),유병소(Ryu, Byung-So) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.9

스크라이빙 공정은 LED 칩 생성을 위한 절단 공정으로 칩의 특성 및 생산량을 결정하는 중요한 공정이다. 기존의 기계적 방식 및 레이저 방식의 스크라이빙 공정은 칩의 열 변형 및 강도 저하, 절단 영역의 제한 등의 문제점이 있다. 이러한 문제를 해결하기 위해 웨이퍼 내부에 공극을 생성하여 자가 균열을 유도하는 내부 레이저 스크라이빙 공정이 연구되고 있으 나 LED 칩 제작을 위한 사파이어 웨이퍼의 절단에 대한 연구는 미비한 실정이다. 본 논문은 LED 칩 제작에 사용되는 사파이 어 웨이퍼의 내부 레이저 스크라이빙 공정을 적용하기 위해 주요 가공 변수를 정립하고 가공 실험을 통하여 절단 특성을 분석함으로써 내부 레이저 스크라이빙 시스템 구축을 위한 기초 가공 조건을 확립하였다. Scribing is cutting process to determine production amount and characteristic of LED chip. So it is an important process for fabrication of LED chip. Mechanical process and conventional scribing process with laser source has several problems such as thermal deformation, decreasing of material strength and limitation of cutting region. To solve these problems, internal laser scribing process that generates void in wafer and derives self-crack has been researched. However, studies of sapphire wafer cutting by internal laser scribing process for fabrication of LED chip are still insufficient. In this paper, cutting parameters were determined to apply internal laser scribing process for sapphire wafer for fabrication of LED chip. Then, foundation of cutting condition was established to set up internal laser scribing system through investigation of cutting characteristics by several experiments.