Key Engineering Materials Vols. 609-610

Abstract: Tool wear is an inevitable and continuously aggravated process in precision hard cutting. Interaction between tool wear and dynamic characteristics in cutting system makes machining accuracy and quality of machined surface declining, which effects dynamic characteristics of cutting system significantly. Based on this, cutter dynamic modal parameters of a specific cutting system are measured in this paper. Cutting force and change law of acceleration power spectrum are studied by experiments. Influence mechanism of tool wear on system frequency energy distribution was obtained, and tool wear effects on the system frequency distribution mechanism is obtained. The cutting system dynamic characteristics are quantified by establishing simulation model. Root locus plot of non-uniform load distribution is obtained and the minimum stiffness ratio in the root locus plot is determined. The effect of tool flank wear on cutting system stability in quantitatively stable is researched. Study results provide theoretical basis for selection of stable precision cutting conditions in different tool wear conditions.

Abstract: The transverse nonlinear vibration of a nanobeam fully clamped at both two ends was investigated using a strain gradient type of nonlocal continuum theory. The small scale effect was considered to the mechanical model at nanoscale. The axial elongation of the nanobeam was taken into account and the nonlinear partial differential equation governing the transverse motion was derived. Subsequently, a perturbation method was applied to the nonlinear governing equation. The dynamical responses of the nanobeam such as transverse displacement and resonant angular frequency were obtained and they were compared with those by a numerical method. The comparison indicated the validity of the present nonlinear model and the multiple-scales analysis method.

Abstract: The inkjet template is an important part of digital printing equipment. The diameter of hole arrays on the template determines the consistency of the ink droplet and thus affects print quality. To improve the printing performance of digital printing equipment, this study investigated the effect of micro-electrical discharge machining (micro-EDM) on the diameter consistency of micro-hole arrays on an inkjet template. Combining block electrical discharge grinding and wire electrical discharge grinding enabled the online processing of the fine tool electrode, whose diameter can be stably controlled at less than 45 μm, whose maximum diameter deviation was about 1 μm. The tool electrode can also be used to process micro-hole arrays. Subsequently, the relationship between the discharge energy of micro-EDM and the erosion material was theoretically analyzed, as was the effects of the diameter consistency of the micro-electrode itself on that of the micro-hole array processed by the micro-electrode and the relationship between processing parameters and the discharge gap between the micro-electrode and the workpiece. Experimentations were conducted on the effect of the flow rate, flush angle, and rotation speed of the electrode and the resistivity of de-ionized water to the diameter consistency of the micro-hole arrays. On the optimized parameters, a 16×16 micro-hole array with a diameter deviation of less than 2 μm was successfully processed, and the average diameter of the holes, about 44 μm, was used for the inkjet template. Beside, an electrode with a diameter of 14μm is also machined and it was used to process a 8×8 micro-hole array, whose diameter deviation is 0.9μm and average diameter is less than 20μm. Large number of experiments show that by the proposed method, one electrode can stably machined 800 holes with diameter less than 50μm, and their diameter deviation is less than 3μm. ​The digital printing equipment with these holes can meet the current demand for components with micro-hole arrays.

Abstract: According to the status of the lack of reliability data for MEMS fuze, this paper mainly studied the reliability factors of MEMS Safety and Arming System by using Dynamic simulation method. Through simulation analysis, the mainly reliability factors, weakness and potential failure modes of MEMS Safety and Arming System can be obtained, which can provide theory reference and data support for the design and application of the MEMS Safety and Arming System.

Abstract: A method of simulating nanoimprint process dynamically is proposed and a software program has been made to complete the simulation process automatically. Finite element method (FEM) is used to reveal mechanism of how the liquid flow in the imprint process by every static state. By means of static model iteration,we make a software to simulate the flow process dynamically and it can be used to forecast the result of the nanoimprint. The simulation system is used to predict residual layer thickness in the waveguide fabrication process.

Abstract: The radio frequency (RF) performances of MEMS suspended spiral inductor under high overload environments are studied. Firstly, a suspended spiral inductor and its MEMS surface micromachining process which is compatible with CMOS process are developed. Then, the mechanical responses and RF performances of the inductor are simulated by ANSYS and HFSS, respectively. The simulation results show that, as the overload increases, the inductance and quality factor decrease significantly when the frequency band is closed to the resonant frequency but have no significant change when the frequency band is much lower than resonant frequency_; the resonant frequency of the suspended inductor decreases monotonically with the increase of overload. A modified lumped parameter model is utilized to illustrate the simulation results, which theoretically indicates that the substrate loss is more severe than the ohmic loss as the overload increases.

Abstract: Targeting at the independent compensation characteristics of cone motion effect and sculling motion effect in traditional SINS Algorithm, this article studies the SINS Algorithm based on spiral vector which enables the cone motion effect and sculling motion effect to compensate at the same time, so as to realize the high precision calculating of attitude Angle and velocity vector. This paper analyzes the mathematical relationships between spiral vector and position-attitude dual quaternion, and then deduces the spiral vector differential equation in detail, which leads to the SINS Algorithm orchestration based on the spiral vector. Finally, considering the real application environment, the actual tests have shown that under the same conditions the spiral vector algorithm of SINS is more precise than the traditional algorithm in high dynamic environment and that the high sub-sample precision is higher than the low sub-sample.

Abstract: Pattenless Casting Manufacturing (PCM) technique is a kind of Rapid Prototyping based on droplet injection, using discrete nozzle to jet the catalyst. The quality of scanning lines has the most important effect on the sand strength, its surface quality and dimensional accuracy. The penetration and curing rules of the catalyst in the resined-sand particles are the main factors to determine the shape of the scanning lines. In order to study the penetration rules of the catalyst in the resined-sand, the penetration process of a single droplet and scanning lines are analyzed theoretically and verified by experiments. The important parameters of the forming process are determined based on the research and experimental results. It will provide the foundation to improve the forming quality of PCM technique.

Abstract: In order to meet the machining demand of the metal components with micro/meso-scale, a kind of micro-fabrication method is explored by Wire-cut Electric Discharge Machining (WEDM). To find solutions for the problems of machining, a series of WEDM experiments for the micro/meso-scale structure of a thin nickel plate are carried out based on the analysis of technology regularity of WEDM. Experimental results indicate that the reasonable constraint on the discharge energy is the key to finish the machining of the metal components with micro/meso-scale. The stable machining can be achieved by adjusting discharge parameters to lower levels. The micro/meso-scale machining defects of cantilever distortion and sharp corners bending can be solved by segmented and multiple cutting accordingly. At last, some examples of complex structures machined are shown.

Abstract: To study the heat transfer performance of micro heat pipe, theoretical analysis of flat plate micro heat pipe with trapezoid cross section are presented in this paper. A one-dimensional stationary mathematical model for micro heat pipe grooved capillary flow using finite volume method (FVM) was established. The micro heat pipe had vapor space connect with each other and the influences of shear stress between vapor and fluid in the working process were described in the model which made the model more precisely. The axial variation of working fluid distribution in the heat pipe, pressure difference between vapor and liquid, and velocity of vapor and liquid were analyzed. In addition, the maximum heat transport capacity of micro heat pipe was calculated. The simulation results showed good agreement with the experiment results, and it could predict the heat transfer performance accurately, which was useful to micro heat pipe structural design.