Materials Science Forum Vols. 505-507

Abstract: A micropump with the function of ejecting droplet is designed and fabricated. It consists of the three components including the PZT actuator, pump body and nozzle plate. The pump body is made of the silicon while the nozzle plate is formed by nickel electroforming. The nozzle plate with single orifice is assembled to the pump body. The micropump is designed with the rectangular pressure chamber and the diffuser as the dynamic passive valve. It is driven by the PZT actuator which deflects the rectangular diaphragm through a bulge on diaphragm. The design of diaphragm with a bulge makes the assembly of the actuator easier and generates sufficient volume displacement. The volume displacement is not only predicted by ANSYS simulation but also verified by 2-dimensional laser scanning vibrometer. And, the prediction and measurement agree to some extent. The ejected droplets are observed by a visualization setup.

Abstract: Valve-less micropumps with one or two piezoelectric buzzers are manufactured and tested. Piezoelectric buzzers are chosen as actuation elements because they are cheap and with high actuation amplitude. The micro-chamber with nozzle and diffuser is fabricated by employing UV photolithography and film mask. A negative photoresistive material, SU8-50, is used as a structure material, and exact angles in the inlet/outlet elements can be obtained. PDMS is chosen to bond different parts of the micropump. The piezoelectric buzzer does have nice actuation amplitude of 40.4 μm after the assembly with the chamber. The results indicate that the micropump with one piezoelectric buzzer has a maximum flow rate of 90.28μl/min when the buzzer is actuated at 100 V and 20 Hz. A maximum backpressure of 50 mm H2O occurs as the buzzer is actuated at 100 V and 30 Hz. For the micropump with two piezoelectric buzzers, it has a maximum flow rate of 165.32 μl/min when the buzzer is actuated at 100 V and 20 Hz and has a maximum backpressure of 84 mm H2O as the buzzer is actuated at 100 V and 30 Hz.

Abstract: This paper develops models for micro-fluid flow in tubular microchannels with uniform or varying cross-sections. The fluid flow is governed by the pressure drop, the capillary force, and the viscous force. The governing equation developed for the flow incorporates two geometry parameters, namely the cross-section perimeter, S, and the cross-section area, A. In a microchannel with a uniform cross-section, the governing equation reduces to a linear initial value problem which can be solved analytically. However, in the case of a varying cross-section, the two geometry parameters vary as a function of the flow front position, L, and the nonlinear initial value problem must be solved numerically. The computational models developed in this study will be able to provide accurate predictions of the micro-fluid flow behavior in microchannels with uniform or varying cross-sections.

Abstract: A hard coating silicon oxide film was deposited on flexible substrates by a PECVD system. Tertramethylsilane (TMS) and oxygen were employed as raw materials. Surface roughness and hardness of these films deposited under various TMS/O2 gas flow ratio, rf power and chamber pressure were investigated. At adequate fabricated conditions, the original surface roughness of PMMA (~ 3.36 nm) and PC (~ 1.38 nm) substrates was markedly flatted to 1.52 and 0.39 nm, respectively. Meanwhile, the surface hardness of coated PMMA and PC substrates was also enhanced to 6.077 GPa and 3.978 GPa, respectively. The hardness of silicon oxide film deposited by TMS-PECVD system was superior to silicon oxide films prepared from e-beam evaporation and dipping technologies.

Abstract: In this study, a three-body microcontact model for rough surfaces is proposed in order to understand the effects of particles between surfaces on contact characteristics and its application on polishing of wafer. Both transitional surface-to-surface and particle-to-surface two-body microcontact simulations can be obtained according to the simplification of this model. In the three-body contact situation, the curves of contact area ratio versus dimensionless load are located in the range between two straight lines. The surface-to-surface two-body contact situation is the upper bound and the particle-to-surface two-body contact situation is the lower bound. As the value of D/σ increases, the contact situation will approach the pure particle-to- surface 2-body contact situation. The model also is used to study the wear mechanisms of the silicon wafer.

Abstract: Today, Programmable Logic Controllers (PLCs) are widely used at the modern manufacturing automation. With an increasing demand for networking facility as well as a natural, intuitive man-machine interaction in automated industry, the graphical programming for multi-PLC control is gaining much attention nowadays. This paper develops a PC-based virtual instrument (VI) that can carry out a remote monitoring and control for up to eight-PLC-based precise riveting systems via the Internet. The real-time implementation shows its good performance and presents the illustrative demonstration.

Abstract: Multicoil inside solidification combined winding machine, which can wind, solidify inside and extract high-pressure glass reinforced plastic (GRP) tubes, combines three conventional working procedures. The machine tool has four spindles of two groups working coordinately, improving machining efficiency greatly. This paper presents the realization of its control system, including the hardware and software architecture of the winding, inside solidification and extraction subsystems, and the mutual communication among them. Several key technologies such as the realization of openness, multicoil winding for heavy caliber tubes and remote control are also introduced.

Abstract: The stiffness of the HSK tool system directly influences the efficiency and the quality of high-speed machining. Based on the mechanics of materials and finite element method, theoretical analysis and digital simulation are done with the stiffness of the HSK tool system. An equation to calculate the deformation angle of the HSK shank is proposed. The basic change law of the stiffness of the HSK tool system is shown and it offers theoretical base for properly applying the HSK tool system to maximize benefit. It is important in theory and application area to develop new-style tool system with our own intellectual property.

Abstract: This paper presents a new development of a real time monitoring subsystem in a general-purpose real time monitoring and diagnosing system using controller area network (CAN) technology. To validate the designed concept, several vehicle electric utility devices are constructed as CAN nodes and are integrated into the CAN bus. An intelligent transducer to convert utility current and voltage is designed and fabricated with micro-controllers. An automatic node detection mechanism is also developed and added to detect the newly jointed/retrieved nodes and record the running history for further diagnosis when system or device malfunction happens. The system design configuration, implementation and verification are demonstrated with actual test data, and the test results demonstrate that the proposed system accomplishes real time electric power monitoring with diagnosis capability.