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Ultrasonic atomization of highly viscous biodegradable oils for MQL applications
Axel Lefebure,심동하 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.12
This paper establishes the vibrating-mesh ultrasonic mist-generation of highly viscous biodegradable oils as a novel implementation for MQL (minimum quantity lubrication) applications. Initial studies on ultrasonic MQL have already been carried out, but the usage of highly viscous biodegradable oils in a non-diluted setup has never been explored. This research studied the atomization rate and mist droplet size distribution, influenced by oil viscosity, and actuator-related properties, such as mesh pore size and driving voltage. Through the FLDC (fibre liquid delivery column) method, using a 113 kHz vibrating mesh piezo actuator, solution feasibility was shown for three currently in-industry-used highly viscous MQL oils, including a maximum liquid viscosity of 37 cSt, higher than the previous record of 28 cSt for ultrasonic atomization. An atomization rate of 13.4 ml/h and mean droplet diameter of 27.5 μm were followingly achieved for this new maximum viscosity. The demonstrated setups and their novel atomization performance data were gathered in the form of a design guide, aiding in the future development of ultrasonically atomized viscous oils for MQL applications.
Ultrasonic MQL System for Generating Size-controlled Droplets
Axel Lefebure,Seeun Kim,Yunseo Kang,Hajin Park,Jumi Lee,Seohee Jang,Inho Lee,Juhye Shin,Chang Soo Lee,Deuk Kwi Lee,Young Chang Park,Jin Hur,Hyung Jin Kwon,Dongha Shim 한국생산제조학회 2021 한국생산제조학회지 Vol.30 No.5
We present an ultrasonic MQL system for generating size-controlled droplets, engaging the requirement of variations in MQL droplet size depending on the used machining process and material. The proposed system architecture features four series chambers with a different vibrating mesh actuator; it demonstrates that a wide range of material- and machining process-specific lubrication requirements can be achieved by varying the mist atomization rate and droplet diameter. The vibrating-mesh outlet pore sizes were differentiated between 2 to 20 μm and driven by a 100 V peak-to-peak bipolar sinusoidal voltage. The oil with a kinematic viscosity of 8.9 cSt contacted the atomizing surface using an FLDC-configuration. Four-size mists were generated with mean volumetric droplet diameters of 19.1, 21.7, 39.0 and 48.3 μm; their atomization rates vary between 1.3 to 39.4 ml/h. The droplet size control must provide more flexibility for emerging ultrasonic MQL systems with improved lubrication and optimized machine-working performance.
수용성 절삭유의 부패방지를 위한 온도와 초음파 가진의 영향에 관한 연구
노태민,Axel Lefebure,김민욱,박동혁,최지섭,신대견,김태호,유민혁,고병호,신주혜,이창수,이득귀,박영창,허진,권형진,심동하 한국생산제조학회 2022 한국생산제조학회지 Vol.31 No.2
This study analyzes the ineffectiveness of ultrasonic treatment for used cutting fluid sterilization. The microorganism population in a water-soluble cutting fluid sample was observed while applying a 40-kHz ultrasound with a power density level of 0.27 and 0.37 W/cm², respectively. The ultrasonic treatment was accompanied by a temperature rise due to the heating effect of cavitation or ultrasonic components. It was observed that the population does not vary below ~45℃, and drops rapidly as the temperature rises. This phenomenon is further investigated using a heater to provide the heating effect. The results showed that the population drops faster at a higher temperature; and there was no significant difference in the population pattern between the ultrasonic and heat treatments at a constant temperature of ~50℃. The overall results showed that ultrasonic treatment does not reduce the microorganism population in the cutting fluid, where temperature is a dominant factor.
Maintenance-Centered Sustainability Analysis of Brick and Block Clamp
Anthony Johnson,Axel Lefebure,Juhye Shin,Dongha Shim 한국생산제조학회 2020 한국생산제조학회지 Vol.29 No.2
This paper presents the analysis of the maintenance process effect on the sustainability of a brick and block clamp. Maintenance and refurbishment are essential practices conducted to enhance the sustainability by returning a product to full serviceability and ensuring the safety and usability to prolong the product’s life. Reusing a product through maintenance/refurbishment (M/R) reduces the energy involved in procuring new products, thus, minimizing the energy used during the product life cycle and enhancing sustainability. The maintenance-centered sustainability analysis (MCSA) using an energy balance sheet showed various energies involved in the M/R processes and in each clamp part. The estimated total input and recycle/disposal energy of the clamp with M/R was 9.9% and 8.1%, respectively, compared to clamp without M/R. The results show the benefits of M/R from the quantitative perspective of sustainability. MCSA, combined with other strategies, could be used for enhancing sustainability while reducing life-cost of a product.
Analysis of spray nozzle in 1-channel MQL (minimum quantity lubrication) systems
Juhye Shin,Axel Lefebure,Se Eun Kim,Doyeon Weon,Gwanghun Jeon,Yunseo Kang,Hajin Park,Jumi Lee,Deukgwi Lee,Changsu Lee,Yeongchang Park,Kyeongdong Kim,Sangyeop Lee,Dongha Shim 한국생산제조학회 2020 한국생산제조시스템학회 학술발표대회 논문집 Vol.2020 No.10
Battery-free Digital Tooling Head using Wireless Power Transmission
Seohee Jang,Juhye Shin,Axel Lefebure,Jihye Jeong,Dongha Shim 한국생산제조학회 2021 한국생산제조학회지 Vol.30 No.2
This study demonstrates a battery-free digital tooling head (BF-DTH) for real-time monitoring of a rotating machine tool. As tooling heads include more digital electronics and consume more power with improved functionalities, replacement and management of batteries become major issues. A BF-DTH using wireless power transmission is proposed to resolve these issues. The BF-DTH is composed of a transmitter/receiver (TX/RX) coil pair, converters, a wireless microcontroller and thermal sensor. The microcontroller, powered by a wirelessly transmitted and converted DC voltage, measures the tool’s temperature and continuously transmits data from the rotating BF-DTH to an external wireless terminal. The delivered RX power was measured to be 32 mW at 15% efficiency, with the RX converter providing a constant DC voltage regardless of spindle speeds of up to 1200 RPM. The BF-DTH system could be effectively used for emerging smart factory applications, where smart DTHs consume moderate to high power.
MQL(Minimum Quantity Lubrication) 부품 및 시스템 개선을 위한 기초 연구
신주혜(J. H. Shin),원도연(D. Y. Weon),전광훈(G. H. Jeon),송창민(C. M. Song),남연수(Y. S. Nam),안효진(H. J. An),조소영(S. Y. Cho),Lefebure Axel,이득귀(D. K. Lee),이창수(C. S. Lee),박영창(Y. C. Park),허진(J. Heo),김경동(K. D. Kim),이상엽(S. 한국생산제조학회 2019 한국생산제조시스템학회 학술발표대회 논문집 Vol.2019 No.5