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Optimal Design of Boom for Telescopic Boom Type Forklift Truck
이재학(Jai Hak Lee),김강수(Kang Su Kim) Korean Society for Precision Engineering 2020 한국정밀공학회지 Vol.37 No.6
In this paper, the boom structure of a telescopic boom-type forklift truck was analyzed using ANSYS, a finite element analysis program. As a result, 494.22 MPa exceeded 456.08 MPa, allowable stress of the material, in the second boom. Thus, structural analysis was performed by reinforcing the thickness of the boom and stress was reduced. The experiment was conducted by selecting four factors of the thickness of the boom T1, T2, T3, and T4. Through response surface analysis, the curvature of the factors for stress was confirmed, and T1 was the most influential factor. Through regression equations from the variance analysis of each response, response maximization was performed to optimize mass and stress. As a result, 467.65 MPa was predicted. This exceeded allowable stress of 456.08 MPa. To obtain the result that does not exceed allowable stress, the mass was fixed at 118 kg, the initial value, and multiple response optimization was performed to limit target value and minimize stress. As a result, 432.96 MPa was expected to occur, and structural analysis resulted in 428.87 MPa stress demonstrating 13.22% reduction of stress compared to the existing model, and it is safe because allowable stress was less than 456.08 MPa.
이재학(Jai Hak Lee),구본재(Bon Jae Goo) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
To inspect the image sensor for smartphones, the image sensor and wire pin are mounted on the inspection jig and then an electrical signal is sent to evaluate the operation, resistance, and current to select good and bad products. When the wire pin is inserted into the inspection jig, elasticity and plasticity may occur in the wire pin depending on the angle. In this paper, static analysis and buckling analysis were performed for wire pins by increasing 0.05° from 1.8° to 2°. All static analysis came out safely, and it was confirmed that it was within the elastic section. Buckling analysis confirmed that the greater the angle, the greater the buckling safety factor and lateral displacement.
이재학(Lee Jai Hak) 표준인증안전학회 2011 표준인증안전학회지 Vol.1 No.2
The necessity for improvement of certification system has been increasing to strengthen the competitiveness and growth potential of enterprises in the stiff environment of international trade and technical competition. The unification of national compulsory KC mark and voluntary certification system with mutual recognition among overlapped certification systems are proposed in addition to database, roadmap and enhancement of conformity reliability of certification system.
이재학(Jai Hak Lee),구본재(Bon Jae Goo),김철희(Chul Hee Kim),강성현(Sung Hyun Kang) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
스마트폰용 이미지 센서 검사는 지그에 이미지 센서를 장착 시킨후 전기적인 신호를 보내어 작동 유무와 저항, 전류 등을 평가하여 양품과 불량을 선별한다. 기존 검사 방법은 Pogo Pin으로 Pad 간격 0.25mm까지 가능하였다. 현재 Pad 간격 0.1mm까지 가능하도록 Wire Pin으로 검사를 할 수 있는 고해상도용 이미지 센서 기술을 개발 중이다. KS C 2603, KS B 5233, KS A IEC 62308, KS B 5542를 기반으로 스마트폰용 이미지 센서의 측정용 지그 신뢰성 확보를 위한 주요 시험평가 항목을 분석한다. Image sensors for smartphones send electrical signals by installing image sensors in test jig to evaluate whether or not it is operating, resistance, and current etc. Existing inspection method was possible up to 0.25mm pad spacing with pogo pin. Currently, we are developing high-resolution image sensor technology that can inspect with wire pins so that pad spacing is possible up to 0.1mm. Based on KS C 2603, KS B 5233, KS A IEC 62308, KS B 5542, main evaluating items are analyzed to secure the reliability of jig for the image sensor of smartphone.