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MOTION VELOCITY SMOOTH LINK IN HIGH SPEED MACHINING

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Chinese Journal of Mechanical Engineering 2007年第2期20卷 17-20页

作者： ren kun fu jianzhong chen zichen Mechanical Engineering Department Zhejiang University Hangzhou 310027 China

To deal with over-shooting and gouging in high speed machining, a novel approach for velocity smooth link is proposed. Considering discrete tool path, cubic spline curve fitting is used to find dangerous points, and according to spatial geometric properties of tool path and the kinematics theory, maximum optimal velocities at dangerous points are obtained. Based on method of velocity control characteristics stored in control system, a fast algorithm for velocity smooth link is analyzed and formulated. On-line implementation results show that the proposed approach makes velocity changing more smoothly compared with traditional velocity control methods and improves productivity greatly.

关键词： High speed machining Motion velocity link S-type control equation

Identification of Kinematic Errors of Five-axis Machine Tool Trunnion Axis from Finished Test Piece

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 999-1007页

作者： ZHANG Ya fu jianzhong chen zichen The State Key Lab of Fluid Power Transmission and Control Zhejiang University Zhejiang Industry Polytechnic College

Compared with the traditional non-cutting measurement,machining tests can more accurately reflect the kinematic errors of five-axis machine tools in the actual machining process for the ***,measurement and calculation of the machining tests in the literature are quite difficult and time-consuming.A new method of the machining tests for the trunnion axis of five-axis machine tool is ***,a simple mathematical model of the cradle-type five-axis machine tool was established by optimizing the coordinate system settings based on robot ***,the machining tests based on error-sensitive directions were proposed to identify the kinematic errors of the trunnion axis of cradle-type five-axis machine *** adopting the error-sensitive vectors in the matrix calculation,the functional relationship equations between the machining errors of the test piece in the error-sensitive directions and the kinematic errors of C-axis and A-axis of five-axis machine tool rotary table was established based on the model of the kinematic *** to our previous work,the kinematic errors of C-axis can be treated as the known quantities,and the kinematic errors of A-axis can be obtained from the *** method was tested in Mikron UCP600 vertical machining *** machining errors in the error-sensitive directions can be obtained by CMM inspection from the finished test piece to identify the kinematic errors of five-axis machine tool trunnion *** results demonstrated that the proposed method can reduce the complexity,cost,and the time consumed substantially,and has a wider *** paper proposes a new method of the machining tests for the trunnion axis of five-axis machine tool.

关键词： five-axis machine tool kinematic errors trunnion axis test piece error-sensitive directions

EXPERIMENTAL STUDY ON THE HOT EMBOSSING POLYMER MICROFLUIDIC CHIP

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Chinese Journal of Mechanical Engineering 2008年第3期21卷 87-89页

作者： HE Yong fu jianzhong chen zichen College of Mechanical and Energy Engineering Zhejiang Unviersity Hangzhou 310027 China

Experiments are used to study the fabrication of polymer microfluidic chip with hot embossing method. The pattern fidelity with respect to the process parameters is analyzed. Experiment results show that the relationship between the imprint temperature and the microchannel width is approximately exponential. However, the depth of micro channel isn＇t sensitive to the imprint temperature. When the imprint pressure is larger than 1 MPa and the imprint time is longer than 2 min, the increasing of imprint pressure and holding time has little impact on the microchannel width. So over long holding time is not needed in hot embossing. Based on the experiment analysis, a series of optimization process parameters is obtained and a fine microfluidic chip is fabricated. The electrophoresis separation experiment are used to verify the microfluidic chip performance after bonding. The results show that 100bp-ladder DNA sample can be separated in less than 5 min successfully.

关键词： Microfluidic chip Hot embossing Channel sizes Pattern fidelity

MODELING OF LASER MACHINING ON POLYMETHYL METHACRYLATE TO FABRICATE MICROFLUIDIC CHIP

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Chinese Journal of Mechanical Engineering 2006年第4期19卷 570-573页

作者： fu jianzhong XIANG Hengfu chen zichen School of Mechanical Engineering Zhejiang University Hangzhou 310027 China

The use of a CO2 laser system for fabrication of microfluidic chip on polymethyl methacrylate （PMMA） is presented to reduce fabrication cost and time of chip. The grooving process of the laser system and a model for the depth of microchannels are investigated. The relations between the depth of laser-cut channels and the laser beam power, velocity or the number of passes of the beam along the same channel are evaluated. In the experiments, the laser beam power varies from 0 to 50 W, the laser beam scanning velocity varies from 0 to 1 000 mm/s and the passes vary in the range of 1 to 10 times. Based on the principle of conservation of energy, the influence of the laser beam velocity, the laser power and the number of groove passes are examine. Considering the grooving interval energy loss, a modified mathematical model has been obtained and experimental data show good agreement with the theoretical model. This approach provides a simple way of predicting groove depths. The system provides a cost alternative of the other methods and it is especially useful on research work of rnicrofluidic prototyping due to the short cycle time of production.

关键词： Microfluidic chip Laser machining Polymer material Modeling

Bioprinting of novel 3D tumor array chip for drug screening

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Bio-Design and Manufacturing 2020年第3期3卷 175-188页

作者： Mingjun Xie Qing Gao jianzhong fu zichen chen Yong He State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou 310027China Key Laboratory of 3D Printing Process and Equipment of Zhejiang Province School of Mechanical EngineeringZhejiang UniversityHangzhou 310027China

Biomedical field has been seeking a feasible standard drug screening system consisting of 3D tumor model array for drug researching due to providing sufficient samples and simulating actual in vivo tumor growth situation,which is still a challenge to rapidly and uniformly establish ***,we propose a novel drug screening system,namely 3D tumor array chip with“layer cake”structure,for drug *** gelatin methacryloyl hydrogel droplets(~0.1μL)containing tumor cells can be automatically deposited on demand with electrohydrodynamic 3D *** conductive membrane is introduced as a chip basement for preventing charges accumulation during fabricating and convenient observing during *** chambers formed by stainless steel and silicon interlayer is convenient to be assembled and *** this chip is compatible with the existing 96-well culturing plate,the drug screening protocols could keep the same as *** properties of this chip,namely printing stability,customizability,accuracy,microenvironment,tumor functionalization,are detailly *** a demonstration,it is applied for screening of epirubicin and paclitaxel with breast tumor cells to confirm the compatibility of the proposed screening system with the traditional screening *** believe this chip will potentially play a significant role in drug evaluation in the future.

关键词： 3D tumor array chip(3D-TAC) Gelatin methacryloyl(GelMA) Drug screening In vitro model Bioprinting

APPLICATION OF FEA TO THE COLLOCATION OF ACTUATOR/SENSOR IN THE INTELLIGENT STRUCTURES

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Chinese Journal of Mechanical Engineering 2001年第3期14卷 219-223页

作者： Du Sheliang, Lin Zhongqin (Institute of Mechanical Engineering ,Shanghai Jiaotong University) Yang Keji,fu jianzhong,chen zichen (Zhejiang University) 上海交通大学机械工程学院上海浙江大学浙江

The piezothermoelectric actuator/sensor collocation for advanced intelligent structure is studied. The quasi-static equations of piezothermoelasticity are used to analyze the coupling effects between the displacement, temperature and electric fields of piezothermoelasticity continua and the governing equations for piezothermoelasticity continua are derived to discuss the effects of coupling factors on the control/sensing performance in intelligent structure. Based on those analyses, a finite element analysis model of distributed piezothertnoelectric continua is developed later. The thermal stress and deformation of a beam are calculated by FEA method so as to determine the optimal actuator/sensor placement. Based on the results of the optimal analysis procedure of actuator/sensor placement, some conclusions of actuator/sensor placement are obtained. Thus, the optimal actuator/sensor placement for piezothermoelectric intelligent structure can be found from the actuator/sensor placements available so that intelligent system will have the best controllability and observability.

关键词： Intelligent structure Piezothermoelasticity coupling effects Finite element analysis( FEA) Actuator/sensor collocation

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微热压成型脱模缺陷分析及其脱模装置

机械工程学报 2008年第11期44卷 53-58页

作者：贺永傅建中陈子辰浙江大学机械与能源工程学院杭州310027 浙江省先进制造技术重点研究实验室杭州310027

为了提高热压成型品质,对手动脱模及自动脱模所产生的缺陷进行了分析。采用有限元模拟了高深宽比微结构的脱模过程。模拟结果显示在自动脱模时应力集中主要出现在微结构底部,而最大脱模应力出现在脱模的起始阶段,这时的脱模缺陷主要以... 详细信息

为了提高热压成型品质,对手动脱模及自动脱模所产生的缺陷进行了分析。采用有限元模拟了高深宽比微结构的脱模过程。模拟结果显示在自动脱模时应力集中主要出现在微结构底部,而最大脱模应力出现在脱模的起始阶段,这时的脱模缺陷主要以颈缩和根部断裂为主。而手动脱模引入的微小脱模方向偏差会造成巨大的应力集中,该应力集中在脱模阶段后期达到最大。5°的脱模方向偏差造成的应力集中可达190 MPa,这时的脱模缺陷主要表现为微结构倾倒及其根部断裂。因而对于高深宽比微结构的热压印成型,必须要采用自动脱模装置。为了克服常规自动脱模装置导致聚合物翘曲变形问题,设计了新型的气动脱模机构并集成到自行设计的热压印装备中。随后的压印试验中采用该气动脱模装置成功制得深宽比约为3.3的微结构,证实了该脱模装置的有效性。

关键词：热压脱模应力有限元法聚合物

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五轴加工刀具路径生成的有效加工域规划方法

机械工程学报 2007年第7期43卷 179-183页

作者：俞武嘉傅建中陈子辰浙江大学现代制造工程研究所杭州310027

为复杂曲面五轴数控加工的刀具路径优化生成问题提出一种新的有效加工域规划方法。在对工件被加工表面和刀具的几何特征进行分析的基础上,得到在加工件表面上各处的最优可加工域宽度和刀具切削方向。通过采用离散采样和插值计算生成优... 详细信息

为复杂曲面五轴数控加工的刀具路径优化生成问题提出一种新的有效加工域规划方法。在对工件被加工表面和刀具的几何特征进行分析的基础上,得到在加工件表面上各处的最优可加工域宽度和刀具切削方向。通过采用离散采样和插值计算生成优化的有效加工域集,得到最优化的初始刀具路径;同时建立一种迭代搜索算法,用于解决最优加工域的选择规划问题。采用此算法生成优化的后续刀具路径,使得有效加工域最终完全覆盖整个被加工表面。给出的示例显示相对于传统的五轴加工刀具路径生成算法,有效加工域规划方法可以减少刀具路径的总长度和加工时间,得到更为优化的刀具路径和更好的工件表面质量,因此有效加工域规划方法可以被用于五轴数控加工实践以降低加工成本和提高产品质量。

关键词：刀具路径有效加工域规划五轴数控加工

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复合恒温构件热变形控制技术研究

机械工程学报 2000年第6期36卷 59-62页

作者：居冰峰傅建中陈子辰浙江大学机械工程及自动化系杭州310027

研究了复合恒温构件在机床热变形控制中的应用，在分析相变热传导的基础上，研究了包含相变过程的二维传热特性，利用自适应变网格有限方法计算相变材料复合恒温构件机床立柱及主轴箱的温度场和热变形值，并将之与实测值比较，二者基本... 详细信息

研究了复合恒温构件在机床热变形控制中的应用，在分析相变热传导的基础上，研究了包含相变过程的二维传热特性，利用自适应变网格有限方法计算相变材料复合恒温构件机床立柱及主轴箱的温度场和热变形值，并将之与实测值比较，二者基本吻合。试验结果对精密数控机床热变形控制具有一定的参考价值。

关键词：相变材料复合恒温构件机床热变形控制技术