Abstract: Through-silicon via (TSV) is an emerging technology for three-dimensional integrated circuit, system in package, and wafer level packaging applications. In this study, a wet chemical etching (WCE) process has been employed to enhance the sidewall quality of TSVs fabricated using nanosecond (ns) laser pulses. Experimental results show that the TSV sidewall roughness can be markedly reduced, from micrometer scale to nanometer scale. We concluded that the proposed method would enable semiconductor manufactures to use ns laser drilling for industrial TSV fabrication as the desired TSV sidewall quality can be achieved by incorporating the WCE process, which is suitable for mass production.
Abstract: Abstract- In this paper, a bending machine for tuning optical design of LED module is proposed. The tuning is done by changing the bending angles of each package on a given module with the help of automatic control program. Luminous intensity distribution can be controlled by adjusting the light emission path, which in turn can be implemented as changing the bending angles of individual LED packages on the module. The proposed machine is capable of bending packages to specified angles with errors less than 0.1°. Three-dimensional light distribution for bent package LED modules is also studied based on various application scenarios so that each scenario can have diversified luminous intensity distribution resulting in higher uniformity and better luminance quality. The machine has several advantages, including quick bending, high accuracy, and great customizability. These advantages make the machine meet the requirements of automatic mold forming.
Abstract: The influences of temperature and pressure on the blow forming of CuZnAlZr sheet was investigated under free bulging conditions using argon gas. The effects evaluated were the dome height, measured at the dome apex; the specific thickness, the ratio of the actual thickness to the initial thickness; and the thinning factor, the ratio of the actual thickness to the average thickness. The results show that the dome height and the rate of change of dome height with respect to time, dh/dt, increase with increasing temperature and/or pressure. The specific thickness decreases with increasing fractional height (the ratio of the height of a given point above the base line to the height of the apex), and the specific thickness at the apex decreases with increasing temperature and/or pressure as well. The thinning factor decreases with increasing fractional height. Furthermore, this decrease becomes more significant with an increase in either the forming temperature or pressure. The thinning factor at the apex, as a function of the height to base ratio for all conditions falls into the region between m=0.3 and m=0.75 curves.
Abstract: This study applies the finite element method (FEM) in con-junction with an abductive network to predict springback’s angle during the U-shaped bending process with counter force. To verify the prediction of FEM simulation for springback, the experimental data are compared with the results of current simulation. Bending force, effective stress distribution and springback are investigated for different process parameters, such as profile radius of die, blank holder force and counter force of U-shaped bending process, by finite element analysis. The abductive network is then utilized to synthesize the data sets obtained from numerical simulations. Finally, prediction model is established for predicting springback’s angle under a suitable range of process parameters.
Abstract: This study with constant shear friction uses DEFORM 2D software to perform FEM simulation of backward extrusion, and compares to SUPERFORM FEM simulation to realize the variations of forming conditions with the punch force and the final cup height. Effects of frictional factor, punch nose face angle, punch nose radius, and punch seizing length on equivalent stress, equivalent strain, velocity field, punch force, and deformed shape can be explored. Meanwhile using both FEM softwares to simulate can realize variations of both models in order to provide the reference of backward extrusion.
Abstract: This study investigated the classification error rate of eleven flaws commonly occurred in copper foil. The goal was to online identify the type of the flaw being discovered in order to trace the source of the flaw and act correspondingly. The misclassification rates of four popular classifiers were investigated and compared. The results indicated that the best classification rate can be obtained by choosing Support Vector Machines as the classifier and employing all the ten features. The resulting low classification error rate of 4.41% proved the effectiveness of the derived classifier as well as the suitability of the chosen features.
Abstract: In this paper, tribological behaviours for sintering carbides and DLC/nitride film are discussed. During the wear test, two types of hardened steel are setting to sliding against eight series of carbide specimens in order to compare the wear mode and evaluate the wear performance of sintering carbides, which are made by different process parameters. The experiment result shows that a density ratio of sintering carbide between 86% and 99% does not have obviously different effect on wear resistance. Moreover, molybdenum binder with high diffusibility can improve the wear performance of tungsten carbide, but wear performance of titanium carbide is dependent on the amount of nickel/cobalt binder, separately. On the other hand, SAE52100 substrate absorbs the heat of friction and maintains the coated diamond-like carbon film in an excellent wear performance.
Abstract: This study derives the stress field of the bond rolling of unbounded sandwich sheet with outer soft and inner hard layers at the roll gap considering Coulomb friction between the roll and the sandwich, and Coulomb friction at the interface of the unbounded region. Due to the sandwich sheet unbounded before rolling, three-layer sheets are not bonded firmly. The neutral point between the roll and the sandwich sheet, the rolling pressure distribution along contact interface between the roll and sandwich sheet, the horizontal stress of whole sandwich sheet, the horizontal stresses in the component layers of sandwich, the shear stress at the interface of sandwich sheet, the rolling force, and rolling torque, etc. are effectively calculated via this model. Furthermore, it is of great important to obtain the bonding point at the interface and the thickness ratio of sandwich sheet at the exit from this study. Additionally, the bonding conditions of the unbounded sandwich sheet are found to avoid the failure in bond rolling. This study proposed is suitable for the on-line bond rolling; it offers useful knowledge to conduct the experimental bonding conditions.
Abstract: The application of ultrasonic vibrations superimposed on wire drawing, deep drawing, upsetting and rolling has been developed in the literature before. Few attempts have ever been made to develop the application of the ultrasonic vibration to blanking process. This paper reports an investigation into the effects of the superimposed ultrasonic vibrations of the punch during the blanking process by experimental design and response surface methodology. The effects of the ultrasonic vibration on the punch load and edge profile are systematically studied. The results show ultrasonic vibrations can decrease the punch load and improve the quality of edge profile.