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Insert geometry effects on surface roughness in turning process of AISI D2 steel

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第12期11卷 966-971页

作者： Zahari TAHA Hani-kurniati LELANA Hideki AOYAMA Raja Ariffin RAJA GHAZILLA Julirose GONZALES Novita SAKUNDARINI Sugoro B.SUTONO Centre for product design and manufacturing Faculty of EngineeringUniversity of Malaya department of System design Engineering Faculty of Science and TechnologyKeio UniversityJapan

Surface roughness is an important parameter for ensuring that the dimension of geometry is within the permitted *** ideal surface roughness is determined by the feed rate and the geometry of the ***,several uncontrollable factors including work material factors,tool angle,and machine tool vibration,may also influence surface *** objective of this study was to compare the measured surface roughness (from experiment) to the theoretical surface roughness (from theoretical calculation) and to investigate the surface roughness resulting from two types of insert,‘C’ type and ‘T’ *** experiment was focused on the turning process,using a lathe machine Colchester *** feed rate was varied within the recommended feed rate *** found that there were large deviations between the measured and theoretical surface roughness at a low feed rate (0.05 mm/r) from the application of both inserts.A work material factor of AISI D2 steel that affects the chip character is presumably responsible for this ***,at a high feed rate (0.4 mm/r),the ‘C’ type insert resulted in 40% lower roughness compared to the ‘T’ type due to the difference in insert *** study shows that the geometry of an insert may result in a different surface quality at a particular level of feed rate.

关键词： Surface roughness Turning Insert geometry Feed rate

Injection molding of micro patterned PMMA plate

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 148-152页

作者： Yeong-Eun YOO Tae-Hoon KIM Tae-Jin JE Doo-Sun CHOI Chang-Wan KIM Sun-Kyung KIM department of Nanomanufacturing Technology KIMM 171 Jang-dong Yusung-gu Daejeon 305-343 Korea department of product design and manufacturing Seoul National University of Technology

A plastic plate with surface micro features was injection molded to investigate the effect of pressure rise of melt on the replication of the micro structures. Prism pattern, which is used in many optical applications, was selected as a model pattern. The prism pattern is 50 μm in pitch and 108° in the vertical angle. The overall size of the plate was 335 minx213 mm and the thickness of the plate varied linearly from 2.6 mm to 0.7 ram. The prism pattern was firstly machined on the nickel plated core block using micro diamond tool and this machined pattern core was installed in a mold for injection molding of prism patterned plate. Polymethyl methacrylate （PMMA） was used as a molding material. The pressure and temperature of the melt in the cavity were measured at different positions in the cavity and the replication of the pattern was also measured at the same positions. The results show that the pressure or temperature profile through the process depends on the shape and the size of the plate. The replication is affected by the temperature and pressure profiles at the early stage of filling, which is right after the melt reaches the position to be measured.

关键词： micro prism pattern injection molding replication pressure profile temperature profile

Kinematical system of breadth cam profile design

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Journal of Central South University 2011年第2期18卷 451-457页

作者： SHIN Joong-ho 李琳 YANG Hyun-dai KWON Soon-man department of Mechanical design & manufacturing Changwon National University

The design solutions for breadth cam mechanism was presented. The main topics of the shape design for breadth cam was to calculate the coordinate at each contact point to determine the cam profile. The proposed method according to velocity and geometric relationships of instant velocity centers can easily determine each contact point at any instant moment. The cam profile was defined by contouring of the contact points. And also a program was developed by using Microsoft Visual C++ program,which can quickly and easily draw a 2D cam profile through the displacement diagram. Finally,the program was used to confirm the accuracy on the breadth cam profile design by computer animation graphically.

关键词： cam profile breadth cam reciprocating follower oscillating follower instant velocity center

Dual cycloid gear mechanism for automobile safety pretensioners

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Journal of Central South University 2012年第2期19卷 365-373页

作者： SHIN Joong-ho KIM Chang-hyun YUN Pyeong-hwa KWON Soon-man department of Mechanical design and manufacturing Changwon National University

The most conventional vehicle pretensioner system consists of an internal gear pair with involute teeth. However, it has been well known that the corresponding gear pairs are relatively weak under the situation of impact loadings. To improve this phenomenon, a new pretensioning gear system with cycloid teeth rather than the involute ones was proposed, and dual cycloidal gear mechanisms were designed for satisfying geometric constraints and dynamic loading conditions. The simulations of the prototypes were conducted by LS-DYNA program and the experiments for a prototype were performed for a dynamic model with impact loading devices. The results show that the better operation and the smoother motion are confirmed in the proposed cycloidal gear system rather than the conventional one without interferences between gear teeth under the impact of a crash.

关键词： seat belt pretensioner internal gear pairs involute gear dual cycloid gear

Combustion analysis of a hydrogen-diesel fuel operated DI diesel engine with exhaust gas recirculation

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Frontiers in Energy 2017年第4期11卷 568-574页

作者： M. LOGANATHAN A. VELMURUGAN TOM PAGE E. JAMES GUNASEKARAN P. TAMILARASAN department of Mechanical Engineering Annamalai University Anna- malainagar 608002 India product design and manufacturing Loughborough University Lough- borough LE11 3TU United Kingdom

The rapid depletion of fossil fuel and growing demand necessitates researchers to find alternative fuels which are clean and sustainable. The need for finding renewable, low cost and environmentally friendly fuel resources can never be understated. An efficient method of generation and storage of hydrogen will enable automotive manufacturers to introduce hydrogen fuelled engine in the market. In this paper, a conventional DI diesel engine was modified to operate as gas engine. The intake manifold of the engine was supplied with hydrogen along with recirculated exhaust gas and air. The injection rates of hydrogen were maintained at three levels with 2 L/min, 4 L/min, 6 L/min and 8 L/min and 10 L/min with an injection pressure of 2 bar. Many of the combustion parameters like heat release rate （HRR）, ignition delay, combustion duration, rate of pressure rise （ROPR）, cumulative heat release rate （CHR）, and cyclic pressure fluctuations were measured. The HRR peak pressure decreased with the increase in EGR rate, while combustion duration increased with the EGR rate. The cyclic pressure variation also increased with the increase in EGR rate.

关键词： hydrogen exhaust gas recirculation (EGR),diesel combustion heat release rate (HRR) combustionduration

Lightweight design of 45000r/min spindle using full factorial design and extreme vertices design methods

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Journal of Central South University 2011年第1期18卷 153-158页

作者： PARK Seong-jin LEE Choon-man HWANG Young-kug department of Mechanical design and manufacturing Engineering Changwon National University

Factors for determining the spindle size are the shaft diameter, positions of bearing and motor, and entire length of the spindle. Then, it is important to find the assembling of the optimal design variables, which satisfy the stiffimss and rotational speed required to the spindle. A general full factorial design method was used to verify some factors that affect the natural frequency of a spindle. It is verified that the shorter shaft length and bearing span length represent the higher natural frequency, and there are some effects according to the change in the levels of factors. The detailed spindle dimension is determined by applying an EVD method, which can define the optimal bearing position through considering the limiting condition. Based on the estimated regression model, the optimal spindle size and bearing distance that can improve the primary natural frequency are obtained, and the influence of design factors on the natural frequency is also analyzed.

关键词： high-speed spindle extreme vertices design natural frequency lightweight design full factorial design

Development of a one-axis manipulator for laser-assisted machining

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Journal of Central South University 2013年第2期20卷 378-384页

作者： KIM Dong-hyeon LEE Choon-man department of Mechanical design & manufacturing Engineering Changwon National University

Laser-assisted machining has been considered as a new alternative machining method of difficult-to-cut materials. A laser module with one-axis manipulator is developed to focus on preheating laser beam effectively. First of all, the thermal characteristic analysis was performed to verify the importance of laser module location. Laser module should be moved within 1 mm. Analysis conditions of three positions in driving range of the one-axis manipulator are selected. And a C coupling is used as a connection device for spindle and laser module. An initial model has one C coupling, and the number of C coupling has been increased from 1 to 2 in an improved model. And the analysis is carried out again for the one-axis manipulator. The results of the static analysis, the maximum displacement and the maximum stress are decreased by 22% and 11%, respectively, for the improved model when the laser module is located at farthest away from the spindle unit. As a result of the modal analysis, the first natural frequency mode is increased by 13%, 18% and 12% at these positions of the improved model, respectively. The harmonic analysis of the improved model was performed by analyzing the results of the modal analysis. The maximum deformation was 0.33 mm in driving unit at 222 Hz. And the maximum compliance of the ISO axis direction was 0.23 mm/N. Finally, the one-axis manipulator has been fabricated successfully using the analysis result.

关键词： finite element analysis (FEA) laser-assisted machining manipulator

Development of analysis model for geometric error in turning processes

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Journal of Central South University 2011年第3期18卷 711-717页

作者： LEE Mun-jae LEE Choon-man department of Mechanical design and manufacturing Engineering Changwon National University

A finite element model was established for analyzing the geometric errors in turning operations and a two-step analyzing process was proposed. In the first analyzing step, the cutting force and the cutting heat for the cutting conditions were obtained using the AdvantEdge. Also, the deformation of a workpiece was estimated in the second step using the ANSYS. The deformation was analyzed for a 150 mm-long workpiece at three different measuring points, such as 10, 70 and 130 mm from a reference point, and the amounts of the deformation were compared through experiments. /n the results of the comparison and analysis, the values obtained from these comparison and analysis represent similar tendencies. Also, it is verified that their geometric errors increase with the increase in temperature. In addition, regarding the factors that affect the deformation of a workpiecc, it can be seen that the geometric error in the lathe is about 15%, the error caused by the cutting force is about 10%, and the deformation caused by the heat is about 75%.

关键词： geometric error machining accuracy finite element analysis turning cutting force, cutting temperature

Estimation of deformed laser heat sources and thermal analysis on laser assisted turning of square member

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Journal of Central South University 2012年第2期19卷 402-407页

作者： KIM Jae-hyun KIM Kwang-sun CHOI Jun-young LEE Choon-man department of Mechanical design and manufacturing Engineering Changwon National University

Laser assisted machining （LAM） has difficulties in estimating temperature after applying a LAM process due to its very small heat input area, large energy and movement. In particular, in the case of laser assisted turning （LAT） process, it is more difficult to estimate the temperature after preheating because it has a shape of ellipse when a laser heat source is rotated. A prediction method and thermal analysis method for heat source shapes were proposed as a square shaped member was preheated. The temperature distribution was calculated according to the rotation of the member. Compared with the results of the former study, the maximum temperature of the calculation results, 1 407.1 ℃, is 8.5 ℃ higher than that of the square member, which is 1 398.6 ℃. In a LAT process for a square member, the maximum temperature is 1 850.8 ℃. It is recognized that a laser power control process is required because square members show a maximum temperature that exceeds a melting temperature at around a vertex of the member according to the rotation.

关键词： laser assisted machining laser assisted turning laser preheating laser power control