A Study on the Machining Characteristics of a Turning-Center by Laser Assisted Machining

이춘만(Choon-Man Lee),김은중(Eun Jung Kim) Korean Society for Precision Engineering 2018 한국정밀공학회지 Vol.35 No.6

This paper is a study of the machining characteristics, cutting force and surface roughness of a turning center by laserassisted machining. The laser-assisted machining (LAM) is an effective method to improve the machinability of difficult-tocut materials. The LAM has recently been studied for various machining processes, but the research on the threedimensional and turning-center machining is still insufficient. In this study, a machining experiment of the turning-center process was performed by the laser-assisted machining with Inconel 718. Before the machining experiment, performed to thermal analysis was for a selected to effective depth of cut. The cutting force and surface roughness were compared and analyzed. The machining experiment confirmed that the machinability was improved in the LAM.

A Study on the Foundation Design of Large Machining Center for Highly Precision

조성화(Seonghwa Cho),이창우(Changwoo Lee) Korean Society for Precision Engineering 2018 한국정밀공학회지 Vol.35 No.6

With the advent of high-tech products, the need for ultra-precision machining has become increasingly necessary, along with the need for a jig center machining center capable of precision machining. A jig center maintains the accuracy of a jig borer, and also has an automatic tool changer like that of a machining center. It performs various machining functions in addition to hole machining and is the most precise and rigid machine tool. Various control methods and analytical techniques to improve machining accuracy are currently being developed in the field of ultra-precise large-scale machine tools. One relevant finding is that the degree of deformation varies depending on the weight of the machine tool as well as the ground conditions. It is therefore necessary to optimize ground conditions before installing the machine tools so as to improve the machining accuracy. The depth of concrete as well as the depth and diameter of grout were selected as variables. We developed the simulation case through structural analysis to consider the position of columns and tables. As a result of optimizing the foundation condition, it was found that the relative displacement error was reduced by up to 98% compared to the rigid foundation condition.

집적화된 Machining Center의 구조해석에 관한 연구

박성진(Seong-Jin Park),이춘만(Choon-Man Lee),김웅(Woong Kim),변삼수(Sam-Soo Byu) 한국기계가공학회 2010 한국기계가공학회지 Vol.9 No.1

An integrated machining center is developed for high precision and productivity manufacturing. The developed machine is composed of the high precision spindle using ball bearings, the high stiffness bed and the three axis CNC controller with the high resolution AC servo motor. In this paper, structural and modal analysis for the developed machine are carried out to check the design criteria of machine. The analysis is carried out by FEM simulation with using the commercial software, CATIA V5, ANSYS and ARMD. The simulation model of machine is made by shell and solid finite elements. This study also presents the measurement system on the modal analysis of an integrated machining center. The weak part of the machine is found by the analytical evaluation. The results provide with the structural modification data for good dynamic behaviors. And the safety of machine is confirmed by the modal analysis of modified machine design. As this study results can be trustworthy with the analysis of ANSYS and CATIA, integrated machining center can be successfully developed.

머시닝 센터 이송계 신장 분석

조창영,최현웅,김동규,추원식,김산,송철기 대한기계학회 2024 大韓機械學會論文集A Vol.48 No.5

공작기계는 제조산업의 기반을 이루는 우수한 성능의 가공정밀도를 가진 핵심 장치이다. 가공 정밀도에 영향을 주는 오차는 다양한 환경 및 조건에서 발생된다. 그 중에서 기계 열변형에 의한 이송축(feed-axis) 열변위(thermal displacement)는 그 크기와 방향을 예측하고 제어하기 어렵다. 이러한 누적된 열변위는 이송축 신장량(elongation amount)으로 정량화될 수 있다. 일부 공작기계 제조사들은 제품출하 전에 조립품질 및 가공정밀도를 검증하기 위하여 이송축 신장 시험(elongation test)을 시행하고 있다. 본 연구에서는 공작기계 머시닝 센터 이송축 위치결정 정도 시험으로 61개 기종의 신장 시험 데이터를 얻었다. 이송축 신장량 절대값을 기준으로 4개 등급으로 분류하여, 공작기계 사양(구조, 가이드 종류, 스트로크 등)에 따른 신장량 특성을 분석하였다. 신장 형태 구분을 위한 최적 기준값을 선정하여 이송축 양 끝단의 위치 이동에 따른 신장 형태를 5가지로 분류하였다. 또한 신장 형태에 따라 가공 오차에 미치는 영향을 분석하고자 하였다. Machine tools are core devices with excellent performance in terms of machining precision and are the foundation of the manufacturing industry. Errors affecting machining precision arise from various environments and conditions. Among them, thermal displacement of the feed axis due to mechanical thermal deformation presents challenges in predicting and controlling its magnitude and direction. This accumulated displacement can be quantified as feed-axis elongation. Some machine-tool manufacturers conduct elongation tests on the feed axis to verify the assembly quality and machining precision prior to product shipment. In this study, we obtain elongation-test data for 61 machine-tool machining centers via feed-axis positioning-accuracy tests. The elongation is classified into four grades based on the absolute value of the feed-axis elongation. We analyze the characteristics of elongation based on the machine-tool specifications, such as the structure, guide type, and stroke. Optimal criteria for classifying the elongation types are selected, and elongation is categorized into five types based on the positional movement of both ends of the feed axis. Additionally, we analyze the effect of elongation type on machining error.

입력성형기법 적용을 통한 머시닝센터의 가공 정밀도 개선에 관한 연구

고강호(Kang-Ho Ko),임동욱(Dong-Wook Lim),홍성욱(Seong-Wook Hong) 한국생산제조학회 2023 한국생산제조학회지 Vol.32 No.4

Recently, machining centers have been actively adopting high-speed positioning systems to enhance operational efficiency and productivity. This study focuses on applying input shaping techniques to a machining center to improve the machining precision. Simulations were performed using a minimal impulse input shaper on a two-axis stage, considering its anisotropic characteristics. A comparative analysis was performed to assess the effectiveness of input shaping by varying the material, feed rate, reduction ratio, and depth of cut. The machined specimens were measured using a digital microscope, surface roughness tester, and an image dimension measurement device. Successful experiments were conducted to demonstrate the improved processing quality of the machining center during combined linear and circular cutting processes. Both the simulations and experiments confirmed the significant effectiveness of the proposed method in enhancing the machining precision of the machining center.

머시닝 센터의 정·동강성 평가에 관한 연구

이춘만,박동근,임상헌 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

A machining center is a complex dynamic system whose behavior influences the machining stability and machined surface quality. This paper focused on establishment of a measurement system and experimental study on static, dynamic, and modal analysis of a machining center. The dynamic stiffness result by the analysis showed the weak part of the machining center. The results provided structure modification data for getting better dynamic behaviors.

Milling Cutter Selection in Machining Center Using AHP

Kyo-Sun Lee(이교선),Soo-Yong Park(박수용),Dong-Hyung Lee(이동형) 한국산업경영시스템학회 2017 한국산업경영시스템학회지 Vol.40 No.4

The CNC machine tool field is showing a growing trend with the recent rapid development of manufacturing industries such as semiconductors, automobiles, medical devices, various inspection and test equipment, mechanical metal processing equipment, aircraft, shipbuilding and electronic equipment. However, small and medium-sized machining companies that use CNC machine tools are experiencing difficulties in increasingly intense competition. Especially, small companies which are receiving orders from 3rd or 4th venders are very difficult in business management. In recent years, company S experienced difficulty to make product quality and delivery time due to the ignorance of the processing method when manufacturing cooling plate jig made of SUS304 material used for cell phone liquid crystal glass processing. In order to solve these problems, we redesigned the process according to the size of our company and tried to manage all processes with quantified data. In the meantime, we have found that there is a need to improve the cutter process, which accounts for most of the machining process. Therefore, we have investigated the correlation between RPM and FEED of three cutters that have been used in the past. As a result, we found that it is the most urgent problem to solve the roughing process during the cutter operation which occupies more than 70% of the total machining. In order to shorten the machining time and improve the quality in machining of SUS304 cooling plate jig, we select the main factors such as price, tool life, maintenance cost, productivity, quality, RPM, and FEED and use AHP to find the most suitable milling cutter. We also tried to solve the problem of delivery, quality and production capacity which was a big problem of S company through experiment operation with selected cutter tool. As a result, the following conclusions were drawn. First, the most efficient of the three cutters currently available in the machining center has proven to be an M-cutter. Second, although one additional facility was required, it was possible to produce the existing facilities without additional investment by supplementing the lack of production capacity due to productivity improvement. Third, the Company’s difficulties in delivery and capacity shortfalls have been resolved. Fourth, annual sales increased by KRW 109 million and profits increased by KRW 32 million annually. Fifth, it can confirm the usefulness of AHP method in corporate decision making and it can be utilized in various facility investment and process improvement in the future.

AHP를 활용한 머시닝센터의 밀링커터 선정

이교선,박수용,이동형 한국산업경영시스템학회 2017 한국산업경영시스템학회지 Vol.40 No.4

The CNC machine tool field is showing a growing trend with the recent rapid development of manufacturing industries such as semiconductors, automobiles, medical devices, various inspection and test equipment, mechanical metal processing equipment, aircraft, shipbuilding and electronic equipment. However, small and medium-sized machining companies that use CNC machine tools are experiencing difficulties in increasingly intense competition. Especially, small companies which are receiving orders from 3rd or 4th venders are very difficult in business management. In recent years, company S experienced difficulty to make product quality and delivery time due to the ignorance of the processing method when manufacturing cooling plate jig made of SUS304 material used for cell phone liquid crystal glass processing. In order to solve these problems, we redesigned the process according to the size of our company and tried to manage all processes with quantified data. In the meantime, we have found that there is a need to improve the cutter process, which accounts for most of the machining process. Therefore, we have investigated the correlation between RPM and FEED of three cutters that have been used in the past. As a result, we found that it is the most urgent problem to solve the roughing process during the cutter operation which occupies more than 70% of the total machining. In order to shorten the machining time and improve the quality in machining of SUS304 cooling plate jig, we select the main factors such as price, tool life, maintenance cost, productivity, quality, RPM, and FEED and use AHP to find the most suitable milling cutter. We also tried to solve the problem of delivery, quality and production capacity which was a big problem of S company through experiment operation with selected cutter tool. As a result, the following conclusions were drawn. First, the most efficient of the three cutters currently available in the machining center has proven to be an M-cutter. Second, although one additional facility was required, it was possible to produce the existing facilities without additional investment by supplementing the lack of production capacity due to productivity improvement. Third, the Company’s difficulties in delivery and capacity shortfalls have been resolved. Fourth, annual sales increased by KRW 109 million and profits increased by KRW 32 million annually. Fifth, it can confirm the usefulness of AHP method in corporate decision making and it can be utilized in various facility investment and process improvement in the future.

Machine capability index evaluation of machining center

홍원표 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.10

Recently, there has been an increasing need to produce more precise products, with only the smallest deviations from a defined target value. Machine capability is the ability of a machine tool to produce parts within the tolerance interval. Capability indices are a statistical way of describing how well a product is machined compared to defined target values and tolerances. Currently, there is no standardized way to acquire a machine capability value. This paper describes how machine capability indices are evaluated in machining centers. After the machining of specimens, straightness, roundness and positioning accuracy were measured using CMM(coordinate measuring machine). These measured values and defined tolerances were used to evaluate the machine capability index. It will be useful for the industry to have standardized ways to choose and calculate machine capability indices.

공작기계의 진동억제를 위한 설계개선 효과

김영조(Young Jo Kim),노승훈(Seung Hoon Ro),신호범(Ho Beom Shin),신윤호(Yun Ho Shin),정근섭(Keun Sup Jung),남규동(Kyu Dong Nam) 한국기계가공학회 2016 한국기계가공학회지 Vol.15 No.3

In modern industries, in whichwhere high productivity is one of the most important concerns, machine tools are facing difficulties to satisfy the high high-speed operation, while and at the same time achieve the precision machining. Generally, the vibrations of the structure increase proportionally to the square of the operating speed so that the precision machining is severely damaged with increased speed. which is a must for the high productivity. Therefore, the suppression of the structural vibrations of the machine tools is the a major concern in the machine tool industry in order to achieve the high productivity and the precision machining simultaneously. In this study, the dynamic properties of a machining center structure were analyzed through the experiment and the computer simulations, and furthermore the results from those were compared to confirm the validity of the simulation model. The design alterations were deduced from the analysis and applied to the simulation model to investigate the effects of those alterations to suppress the vibrations of the machine. The result shows that the relatively simple design alterations, without redesigning the main structure of the machine, can suppress the vibrations effectively.