Applied Mechanics and Materials Vols. 121-126

Abstract: ECMP (Electro-Chemical Mechanical Polishing) presents high removal rate, low polishing pressure and good polished surface because the action of electrochemistry accelerates copper dissolution. It is considered to be a most promising novel Cu planarization process to replace traditional CMP (Chemical Mechanical Polishing). However, the micro asperity heights of coarse surface are often too small compared to the distance between anode and cathode, so the asperities are difficult to be selectively removed. In this paper, high dielectric constant abrasives were used in ECMP to solve this problem. High dielectric constant abrasives can improve the distribution of electric field, amplify the gradient of electric field and enhance the ability of selective removal. Based on the results of experiments, rutile TiO2, as one of high dielectric constant abrasives, is better than SiO2 and anatase TiO2 in ECMP process. The material removal rate of electrolyte containing rutile TiO2 is 0.078mg/min, and the surface roughness is Ra18.2nm.

Abstract: The simultaneous application of Logical reasoning and model design in parametric design technology based on Knowledge fusion in the interactive process of CAD system, makes design process are creative; its key technology includes the building of knowledge model base, the reasonable representation of knowledge items and knowledge constraints, correct establishment of the relation among knowledge item and knowledge constraint reference variable; the paper studies the key technology in parametric design based on Knowledge fusion, expresses the application in sliding screw mechanism of the software based on the key technology, and finally gives an example of parametric design technology of sliding screw mechanism based on Knowledge fusion.

Abstract: A new 5-DOF flexible coordinate measuring machine (CMM) is introduced in this paper, which uses REVO system produced by Renishaw. According to the D-H method, the mathematical model is built, and then the error model of the flexible CMM is derived. The parameter calibration based on the nonlinear least square method is analyzed theoretically. Due to the disadvantages of Gauss-Newton method, LM method is researched, which improved the singularity of the coefficient matrix. The calibration analysis is a basis for improving accuracy of the flexible CMM.

Abstract: Based on the linear theory of permanent magnet linear synchronous motor with low-speed（PMLSMLS）. Equivalent circuit parameters are derived. This equivalent circuit is in the same form for either salient-pole machine or non-salient pole machine without trouble of d-q axis, which can be used to analyze and evaluate the performance of PMLSMLS conveniently.

Abstract: In order to reduce vibration and noise of the compressor used in small and medium-sized refrigeration unit, this paper designs different vibration isolating systems and carries out experimental modal analysis based on LMS Test. Lab Impact Testing software. The comparison results of modal parameters of four different vibration isolating systems show that the natural frequency of single-layer vibration isolating system is higher than that of non-isolation system and effectively avoids the second order resonance frequency. Furthermore the natural frequency of double-layer vibration isolating system has reduced due to the additional middle-mass. And the system's natural frequency decreases obviously with the increase of middle-mass which is far from resonance frequency and significantly improve the effect of vibration isolating system.

Abstract: In the present study, fabrication of the aluminum (Al) foam through sintering and dissolution process and effect of space holder (NaCl) mean size on compressive behavior of metallic foam has been investigated. Due to improper cold bonding between Al particles in low compaction pressure spalling of the foam was observed. Appropriate compacting pressure and sintering temperature of the compacts resulted in production of high quality Al foams. SEM was used to characterize the morphology of produced Al foam and mechanical behavior of produced foams was evaluated using compression test machine. The results show that open-cell Al foam free from cracks was obtained and an increase in NaCl mean size resulted in increases of the compressive strength, Young modulus and plateau stress of the stress-strain curves.

Abstract: Taking the bed of a large machine tool as an example, static stiffness and modal analysis were studied by the software HyperWorks. Based on the results of the finite element analysis the structural topology optimization of the bed was compiled, with the optimization target is minimum volume of the rib plate and the bed constraint conditions are stiffness and natural frequency. The lightest topology shape of the bed was obtained in the premise of its stiffness and strength which can provide the guidance for the next precise design of the structure. The results showed that the mass of the bed was reduced by 8.58% while the stiffness improved 7.41%.

Abstract: A piezoelectric gripper with force sensor is presented for an optical precision manipulation. The gripper utilizes flexure hinge mechanisms with two-step amplification to achieve output displacement. Micro displacement amplification principle of the gripper is analyzed and verified using finite element analysis (FEA) soft. A force sensor of resistance strain type with elastic plate structure of bi-cantilever is designed, which is fixed at the bottom of the gripper to detect force signals during the working process. The strain foils adopt a connecting method of full-bridge. According to theoretical analysis and FEA of the force sensor, bonding positions of the strain foils are determined. Experimental results indicate that the sensor has good linearity and little temperature drift and creep, and its resolution is less than 100mN. Micro-vision method is used to test the gripper, and maximum displacement is 302μm.

Abstract: Mechanical engineering field requires engineers with more practical problem-solving experience and skills of thinking, working and acting creatively. But, how can we develop and encourage these important skills in undergraduates This article describes a case of nurturing creativity in undergraduates through cooperation with enterprises. Through the study of cognitive learning and creativity, a series of educational procedures and strategies are presented, they involved in basic training of fostering creativity and higher-level training of developing creativity based on commercial projects. Questionnaires from students and the actual results demonstrate that the above strategies and methods for fostering creativity in mechanical engineering undergraduates have yielded good results and students benefit from them.

Abstract: FPGAs (Field Programmable Gate Arrays) are highly integrated devices which can be programmed as variable functions. The application-level testing of FPGAs usually include multiple reconfigurations and relevant functional tests respectively through ATEs (Automated Test Equipments). However, test engineers are facing a tough problem to reconfigure FPGAs automatically through an ATE instead of using specific tools and download cables provided by FPGAs manufacturers. This paper takes example for XILINX Virtex-E series, presents two different methods for FPGA auto configuration based on an ATE using JTAG configuration interface and boundary-scan protocol, and accomplishes the entire auto configuration-test procedure by a single ATE.