Optical Measurement System for Motion Characterization of Surface Mount Technology

Advanced testing methods for the dynamics of mechanical microdevices are necessary to develop reliable, marketable microelectromechanical systems. A system for measuring the nanometer motions of microscopic structures has been demonstrated. Stop-action images of a target have been obtained with computer microvision, microscopic interferometry, and stroboscopic illuminator. It can be developed for measuring the in-plane-rigid-body motions, surface shapes, out-of-plane motions and deformations of microstructures. A new algorithm of sub-pixel step length correlation template matching is proposed to extract the in-plane displacement from vision images. Hariharan five-step phase-shift interferometry algorithm and unwrapping algorithms are adopted to measure the out-of-plane motions. It is demonstrated that the system can measure the motions of solder wetting in surface mount technology(SMT).

Non-Synchronous Deformation Effect of Particle in Sheet Metal Forming Process

A new concept referred to the non-synchronous deformation effect of particle in sheet metal forming is proposed. The results of finite element analysis show that the flow resistance of sheet metal can be effectively reduced and thus the forming property can be greatly improved if the moving and deformation state of the neighboring elements with equal perpendicular distance to the entrance contour of die is non-synchronous. Experiment tests are presented and the results agree well with FEA simulation. In addition, the mechanism of the non-synchronous effect is analyzed in detail.

Microstructure and cutting performance of Ti(C, N)-based cermets heat-treated in nitrogen

Ti(C, N)-based cermets were treated using hot isostatic pressing (HIP) at 1423 K in nitrogen. The microstructures compared with the as-sintered cermets were investigated using X-ray diffraction, scanning electron microscopy, transmis- sion electron microscopy, energy-dispersive X-ray analysis, and electron microprobe analysis. It was found that high nitro- gen activity in the surface zone resulted in the formation of gradient structure. Approximately 20-μm-deep, nitrogen-rich and titanium-rich hard surface zone was introduced by the heat treatment. The nitrogen activity was the driving force that caused the transportation of the atoms through the binder, titanium towards the surface, and tungsten and molybdenum in- wards. In the surface zone, the particle size became fine, the inner rim disappeared, and the volume fraction of the outer rim and the binder phase considerably reduced. Small grains of TiN, WC, Mo2C, and nitrogen-rich carbonitride phases formed in the surface zone during the heat treatment, improving the tribological property of the heat-treated cermet.

Analysis of Die Forging Process and FEA of Piston

Die forging process of piston tail and its key technology are analyzed in detail. The key issue is to reduce friction force between punch and billet to facilitate metal flow towards two ends. Three-step forging scheme is used, namely preforming, final forging and cutting the flash. Preforming is critical for the success of the whole process and two schemes are compared. First two steps are simulated using 3D-Deform software. Simulation results show that the process is feasible and its validity is verified.

Microstructure and properties of indium tin oxide thin films deposited by RF-magnetron sputtering

Tin-doped indium oxide (ITO) thin films were prepared using conventional radio frequency (RF) planar magne-tron sputtering equipped with IR irradiation using a ceramic target of In2O3/SnO2 with a mass ratio of 1:1 at various IR irradiation temperatures TI (from room temperature to 400°C). The refractive index, deposited ratio, and resistivity are functions of the sputtering Ar gas pressure. The microstructure of ITO thin films is related to IR TI, the crystalline seeds appear at TI = 300°C, and the films are amorphous at the temperature ranging from 27°C to 400°C. AFM investigation shows that the roughness value of peak-valley of ITO thin film (Rp-v) and the surface microstructure of ITO thin films have a close relation with TI. The IR irradiation results in a widening value of band-gap energy due to Burstein-Moss effect and the maximum visible transmittance shifts toward a shorter wavelength along with a decrease in the film’s refractive index. The plasma wavelength and the refractive index of ITO thin films are relative to the TI. XPS investigation shows that the photoelectrolytic properties can be deteriorated by the sub-oxides. The deterioration can be decreased by increasing the oxygen flow rate (fo2), and the mole ratio of Sn/In in the samples reduces with an increase in fo2.

Dynamic Mechanical Behavior and Prediction for PP/POE Blends

Polypropylene(PP)/ethylene-octene copolymer(POE) blends were prepared with a twin-screw extruder.Their dynamic mechanical behavior were systematically investigated.The results show that PP/POE blends are heterogeneities with a partial compatible two-phase structure,the glass transition temperature of PP phases in the blends tends to shift towards high temperature with increasing the POE content,and the glass transition temperature of POE phases shifts towards the low temperature with increasing the PP content.The Kerner's dispersed phase model and co-continuous phase model can reasonably predict the visco-elasticity of PP/POE blends with different compositions.Additionally,the morphological structure of the blends can be estimated via comparing the predicted DMA behavior with the experimental data.

Un-thorough Delaunay Approach for Tetrahedral Mesh Generation

An integrated tetrahedrization algorithm in 3D domain which combines the Delaunay tetrahedral method with un-Delaunay tetrahedral method is described . The algorithm was developed by constructing Delaunay Tetrahedrons from a scattered point set, recovering boundaries using Delaunay and un-Delaunay method, inserting additional nodes in unsuitable tetrahedrons, optimizing tetrahedrons and smoothing the tetrahedral mesh with the 2D-3D Laplacian method. The algorithm has been applied to the injection molding CAE preprocessing.

Microstructure and properties of indium tin oxide thin films deposited by RF-magnetron sputtering

Tin-doped indium oxide （ITO） thin films were prepared using conventional radio frequency （RF） planar magnetron sputtering equipped with IR irradiation using a ceramic target of In2O3/SnO2 with a mass ratio of 1∶1 at various IR irradiation temperatures T1 （from room temperature to 400?℃）. The refractive index,deposited ratio,and resistivity are functions of the sputtering Ar gas pressure. The microstructure of ITO thin films is related to IR T1,the crystalline seeds appear at T1=300?℃,and the films are amorphous at the temperature ranging from 27?℃ to 400?℃. AFM investigation shows that the roughness value of peak-valley of ITO thin film （R p-v ） and the surface microstructure of ITO thin films have a close relation with T1. The IR irradiation results in a widening value of band-gap energy due to Burstein-Moss effect and the maximum visible transmittance shifts toward a shorter wavelength along with a decrease in the film’s refractive index. The plasma wavelength and the refractive index of ITO thin films are relative to the T1. XPS investigation shows that the photoelectrolytic properties can be deteriorated by the sub-oxides. The deterioration can be decreased by increasing the oxygen flow rate （fo2）,and the mole ratio of Sn/In in the samples reduces with an increase in fo2.