• 한국기계가공학회지
• /
• 제20권1호
• /
• pp.66-73
• /
• 2021

In this paper, we analyzed and considered the precision of parts produced by 3D printing methods. For the latch systems applied to the Wingline folding doors, the 3D shape of the door hinge part was printed using FDM and DLP methods. Then, the 3D printed shape was scanned to measure the dimensions and dimensional changes of the actual model. In the comparison and analysis of the 3D printed door hinge parts, because the output filling density is 100% owing to the characteristics of DLP 3D printing, the filling density in FDM 3D printing was also set to 100%.

• Design & Manufacturing
• /
• 제17권3호
• /
• pp.15-20
• /
• 2023

In the fine blanking process, which is a press operation known for producing parts with narrow clearances and high precision through the application of high pressure, die roll often occurs during the shearing process when the punch penetrates the material. This die roll phenomenon can significantly reduce the functional surface of the parts, leading to decreased product performance, strength, and fatigue life. In this research, we conducted an in-depth analysis of the factors influencing die roll in the curvature area of the fine blanking process and identified its root causes. Subsequently, we designed and experimentally verified a die roll reduction process specifically tailored for the door latch manufacturing process. Our findings indicate that die roll tends to increase as the curvature radius decreases, primarily due to the heightened bending moment resulting from reduced shape width-length. Additionally, die roll is triggered by the absorption of initial punch energy by scrap material during the early shearing phase, resulting in lower speed compared to the product area. To mitigate the occurrence of die roll, we strategically selected the Shaving process and carefully determined the shaving direction and clearance area length. Our experiments demonstrated a promising trend of up to 75% reduction in die roll when applying the Shaving process in the opposite direction of pre-cutting, with the minimum die roll observed at a clearance area length of 0.2 mm. Furthermore, we successfully implemented this approach in the production of door latch products, confirming a significant reduction in die roll. This research contributes valuable insights and practical solutions for addressing die roll issues in fine blanking processes.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
• /
• 제23권4호
• /
• pp.7-15
• /
• 2017

Purpose: The Korean government has implemented a Barrier Free Certification System since 2008 to create a secure and convenient environment for the socially disadvantaged. The drastic increase in the number of BF-certification facilities is expected due to the revision of the system and increasing the number of certification institutions. An analysis of individual evaluation items needs to be made for the BF-Certification with public confidence. Method: Korean standard, International Standard(ISO/FDIS 21542, 2011), German Standard(DIN 18040-1, 2010), Austrian Standard(${\ddot{O}}NORM$ B 1600, 2017) and Swiss Standard(Norm SIA 500 / SN 521 500, 2009) were investigated and analyzed. A comprehensive improvement plan is proposed by comparing details of the aforementioned standards and the evaluation items of BF-Certification. Results: Many problems arise in applying existing Barrier-free standards due to changes in population structure, environmental change and the use of powered wheelchairs. International standards are being improved to solve these problems. The korean standards also require improving of the Barrier Free Law and Certification System, which reflect these trends. In korean cases, standards such as the size of the doors (width and height), the Unobstructed Manoeuvring Space and Clear Space at the Latch side of the Door are required to improve standards in accordance with international standards. In addition, the expression of laws and evaluation items of BF-Certification should be clearly defined. And the application of visual contrast standards for the enhancement of perceptions presented in international standards should be considered. Implication: Barrier Free related legal standards and evaluation items of BF-Certification that are used in Korea are required to be revised in consideration of social and environmental changes. Comprehensive improvements should be made through detailed review.

• 한국산학기술학회논문지
• /
• 제12권2호
• /
• pp.565-570
• /
• 2011

본 연구는 파인 블랭킹(fine blanking) 프레스로부터 기능면으로 사용되는 100% 매끄러운 전단면을 얻는 파인 블랭킹 공정에서 다이 롤(die roll) 크기를 최소화하기 위한 목적으로 실험을 통해 다이 챔퍼(die chamfer) 형상에 따라 성형되는 제품의 다이 롤 크기 변화를 검토한 것이다. 다이 챔퍼가 다른 여러 가지 다이 편(die insert)을 제작하여 파인 블랭킹 실험을 실시한 후 다이 챔퍼 형상에 따른 다이 롤 크기를 측정 분석하여 두께 방향 다이 롤 크기의 경향을 파악하였다. 이 연구 결과는 파인 블랭킹 판재 성형에서 두께 방향 다이 롤 크기를 최소화하기 위한 다이챔퍼 설계에 유용하게 적용될 것으로 판단된다.