Advanced Materials Research Vol. 422

Abstract: In order to improving reliability and economy of down-lead bonding of MEMS packaging , NiPdAu PCB is leaded in ,because palladium is joined in protecting involucra , bonding technology parameter must change . In this paper , robust parameter design method of DOE is used and optimize bonding technology parameter of new type NiPdAu involucra has been discovered , according to optimize results , mending bonding technology parameter and Ni Pd Au PCB is triumphantly used into MEMS packaging technology , not only increasing reliability of products , but also reducing cost of raw materials and obtaining well economy benefit.

Abstract: Microscale polyurethane modified epoxy resin film has been fabricated using MEMS tehnologies in the present paper. The effect of different process conditions on the thickness of fabricated film was discussed. The microscale film shows smooth and uniform surface morphology. The tensile test of the film by DMA indicates its tensile strength and Young's modulus are approximately 55MPa and 1.8GPa, respectively. The fracture section of the film was characterized by SEM. In addition, the interface bonding strength of the fabricated film between Ni substrate is much higher than Parylene-C and SU-8. This microscale polymer film is promising in several smart MEMS fields, especially bio-MEMS structures.

Abstract: Led die bonder used for bond lead frame and chip is one of the key equipment of led production line. The swing-arm is an important component of led die bonder and its dynamic characteristics will directly affect the piece accuracy. At present, the accuracy and efficiency of led die bonder are limited because of the vibration of the swing-arm. In solving this problem, a three-dimensional finite-element model for swing-arm is built to provide analytical frequencies and vibration modes. Then the modal distribution and vibration mode shapes for swing-arm are obtained after analyzing the modal by ansys10.0. Finally the dynamics effects of this structure by modal frequency and vibration mode are analyzed. The modal analysis of structural would provide the reference to dynamics analysis and structural optimization for swing-arm in practical use.

Abstract: LN is a kind of pyroelectric material. It can be made into a sensitive layer belonging to photoelectric detector’s sensitive element. Usually, the thickness of LN wafer is 0.5mm and that is beyond the requirement for thickness of photoelectric sensitive element. Due to that, LN wafer must be disposed of by bonding, thinning and polishing process. The process mainly contain RZJ-304 photoresist bonding, grinding, polishing, stripping liquid stripping and acetone cleaning. After processed, the dimension of LN wafer is 10mm×10mm×50um. The surface of LN is very smooth, and the surface roughness is 1.63nm.The test shows that the disposed wafer’s peak value of pyroelectric signal is four times as much as that of undisposed one.

Abstract: In order to meet the demand for high power linear ultrasonic motors (LUSMs) for many applications, the concept, asynchronous parallel connection (APC) of LUSMs, has been proposed. The basic principle is that multiple stators (vibrators) alternately drive a slider (rotor) in a vibration cycle, the actual driving frequency then increases by the order of the quantity of stators, and better output performance can be obtained. Analysis shows, in the APC, increasing the contact frequency between stator and slider can enhance the output force, speed of LUSM, while at the same time, the mutual interference of different stators in synchronous parallel connection (SPC) can be avoided. Experimental results of double-driving-tips LUSMs demonstrate that, in APC, over 30% more loading force is obtained than in SPC, and over 25% more is obtained than the sum of loading forces from single LUSM driven respectively. In APC, the no-load linear velocity of LUSM is increased more than 10% from that of individual LUSM driving.

Abstract: Due to the limitation of dimension, the cooling of microelectronic devices with high heat flux may be sometimes beyond the reach of heat sink which is fabricated with single layer structure, no matter which kind of mircochannel you choose. Various innovative methods have been investigated to tackle this problem. Among them, microchannel heat sink with multilayer structure is possibly one of the most effective cooling techniques. In this paper, the conjugate fluid flow and heat transfer characteristics of multilayer fractal-like microchannel network embedded in a disk-shape heat sink are investigated using a CFD approach. The intrinsic advantages of multilayer fractal-like microchannel network compared with single layer one are demonstrated, such as low total pressure drop, low maximum temperature, and temperature uniformity.

Abstract: Planar pinch micropump with the integration of two diffuser valve elements has been reported. The fabrication of the micropump is carried out by utilizing simple hot embossing technique for microdiffuser imprinting and spin coating for membrane construction. Parameter of diffuser design is optimized via finite element analysis (FEA). The experiment result shows that the pump works well at low frequency of 29 Hz.

Abstract: This article presents a new NURBS interpolation of tool path according to the requirements of machining dynamics, so the NURBS interpolation can satisfies the dynamics condition of the machine. The experimental results confirm that the proposed NURBS interpolator is capable of achieving a satisfactory performance, reducing the impact, machine vibration of feed, and improving the surface accuracy and quality of machining.

Abstract: Based on the dynamic triaxial test of typical soils in Hangzhou area, the existed empirical calculation formulas of cumulative pore pressure and cumulative plastic strain are analyzed to recharacterized variables such as the cyclic stress ratio and the static deviator stress, therefor the modified formulas are proposed. Parameters of cumulative deformation calculation model that suitable for this area are also determined according to dynamic triaxial tests. Thereafter the modified formulas is applied in a subway project under construction in Hangzhou. Results show that both the the cumulative plastic strain and cumulative pore pressure in dynamic triaxial test have the power exponential function relationship with the vibration number, and an inflection point appears in curve when amounts to approximately 1000. The improved formulas basicly tally with test results, of which the cumulative plastic strain formula coinsides better. The formulas work well in calculating the long-term settlement of subway projects in Hangzhou area.

Abstract: Horizontal curved pipe which are widely used in the engineering project and less researched were selected to study in the high concentration of fluidized transportation. Compressed air was used as the transmission power and gypsum powder as the transport medium. And then, the flow characteristics in horizontal curved pipeline of dense phase pneumatic conveying gypsum powder were achieved. The experimental results showed that the geometry parameters such as angle of the bend, radius of curvature and operating parameters i.e. conveying pressure, gas velocity, solid velocity etc have a dominant effect on the gas solid flow process.