Papers by Author: Kuen Ming Shu

Abstract: The acoustic solid horns are the important parts in high power ultrasonic vibrating systems, and its design is critical to the quality and the efficiency of ultrasonic welding. The using of multiple function acoustic horn can reduce machining time very effectively. This paper performs the analysis and design of multiple function acoustic horns for ultrasonic welding of plastic by employing ANSYS finite element software. Firstly, the theoretical dimensions of the horns are calculated. Moreover, their natural frequencies and amplitudes are obtained through the simulations of ANSYS. Experiments are currently being set up to verify the validity of the analytical results.

Abstract: The acoustic horn plays a very vital part in high energy ultrasonic machining, and its design is critical to the quality and the efficiency of ultrasonic machining. This paper performs the analysis and design of acoustic horns for ultrasonic welding Teflon encapsulated O-ring by employing ANSYS finite element software. Firstly, the theoretical dimensions of the horns are calculated. Moreover, their natural frequencies and amplitudes are obtained through the simulations of ANSYS.

Abstract: Solar panels conduct electricity through aluminum strips on substrate surfaces. Ultrasonic roll welding can weld the conductive aluminum strips onto the glass substrates. This paper illustrates vibration characteristics and optimal design of amplitude horns used in the ultrasonic welding roll. Based on theoretical equations, this study used the ANSYS software to establish the parametric model according to design requirements. With the parametric model as the initial design, this study conducted modal analysis and harmonic analysis to obtain the vertical mode and disc bending mode of the horn, and measured the resonant frequency, amplitude amplification rate and stress distribution. Finally, this study implemented and verified the optimal coupled disc tool of the ultrasonic horn.

Abstract: Previous studies on the amplitude horn only calculated sizes in consistent with the axial resonant mode frequency and disc bending resonant mode frequency without considering the overall stress and the amplitude of the disc’s outer ring. The resonant frequency of the amplitude horn cannot occur around 35 kHz. Such a design results in the inability to weld and may damage solar panels or lead to poor welding quality. Using the optimization method to address these problems, the proposed design process in this study is to conduct sensitivity analysis by the gradient method to understand the impact of design variables on the objective function for the selection of design variables. Then, this study applied the random search method to find out the feasible design of arrays to optimize the structure of two arrays closest to the design objective by the full factorial experiment method to ensure to get the global optimal solution rather than the local optimal solution. Finally, by design examples, this study used the sub-problem approximation method to search the optimized solution and compared the differences of the two methods, in order to confirm whether the objective of optimized design of amplitude horn had been achieved.

Abstract: The acoustic horn plays a very vital part in high energy ultrasonic machining, and its design is critical to the quality and the efficiency of machining. This paper performs the analysis and design of acoustic horns for ultrasonic machining by employing ANSYS finite element software. Firstly, the theoretical dimensions of the horns are calculated and compared to three commercial available horns with different shapes. Moreover, their natural frequencies and amplitudes are obtained through the simulations of ANSYS. Finally, the numerical results are compared with commercial available horns.

Abstract: The Taguchi Method was applied in this study to discuss the mechanical strength of heterogeneous plastic materials by ultrasonic-aided spin welding. Two heterogeneous plastic workpieces were rotated by a high speed motor, to make the top of conducting energy angle generate the high temperature due to friction. When the thermoplastic material reached the heat distortion temperature, a proper pressure was exerted on another material, the surface would be welded in a semi-melted state. Then the process conditions of ultrasonic welding were arranged by using the standard orthogonal table of Taguchi Method, and the temperature of the contact friction surface could be increased by the excitation of ultrasonic transducers as well as magnified and displaced by sound wave welding head. The optimal value of tensile strength was obtained by using the Large-the-Best characteristic of the Taguchi Method to obtain the important control factors of this experiment; a validation experiment was carried out by using the adjusted factors.

Abstract: The study aimed at improving the problems of warpage occurring in the mold injection of battery lower cases. Firstly, the effects of variations of molding parameters are investigated in order to minimize the warpage. Secondly, Moldflow software is employed to simulate the molten plastic flow inside the cavity, and followed by the holding pressure analysis. Moreover, Taguchi method is applied to find the optimum distribution of mold temperature, and its results are used to design cooling tubes. Finally, different cooling systems are parametrically simulated and the optimum combinations will be found. The analytical results indicate that the optimum parameters can reduce the warpage problem occurring during mold injection. Therefore, the yield rate of the products can be effectively raised.

Abstract: The main object of the present work was to develop an ultrasonic aided electrical discharge grinding (UAEDG) methodology to remove the re-solidified layer through the grinding induced by a metal matrix composite electrode prior to the re-solidification of molten material. A metal matrix composite (Cu/SiCp) electrode, with an electroless pretreatment of Cu coating on SiCp to enhance bonding status between Cu and SiCp, was employed to study the UAEDG technology. The machinability of the mold steel SKD11 was investigated by the combined technologies of UAEDG. The machined surfaces of these materials were examined by optical microscopy（OM）and their surface roughness measured by a profilemeter.

Abstract: There are several types of welding method to join metal and ceramic. This paper gives a description of an experimental study of the ultrasonic welding of aluminum wire and silicon wafer under the conditions of the frequency of ultrasonic vibration f = 38000Hz, the applied duration T=0.2-1.5 sec, and the welding force Ps =40-140 gf. In this study, vacuum deposition was first applied to deposit surface modification aluminum on silicon wafer, then ultrasonic welding processes were investigated to join aluminum wire and modified silicon wafer. Based on the results of the microstructure observation and tensile test, it is believed that the joining ability can be improved under optimum welding condition.