Advanced Materials Research Vols. 189-193

Abstract: An ultrasonic motor (USM) has been widely used in many applications since it has several advantages over the conventional electromagnetic motor, such as high torque at low speeds, no electromagnetic interference, and high holding torque without power supply. However, in order to achieve high efficiency, its electrical drive system presents unique challenges, especially in producing two-phase signal (high frequency, high voltage, phase difference of two-phase signal) input to a low impedance capacitive motor. In this paper, a novel drive system based on microcontroller (ATmega16) has been proposed for ultrasonic motor. Drive system includes power drive circuit and control system. Power drive circuit is combined from Push-Pull Inverter to provide high-frequency two-phase voltages. A microcontroller was used to control ultrasonic motor drive system. PWM signals were generated and then directly applied to the MOSFET drivers for speed control of ultrasonic motor. The frequency and phase difference of two phase PWM signals can be directly changed by microcontroller. Detailed experimental results are provided to demonstrate the successful of the proposed drive system.

Abstract: This work deals with the processing parameter prediction of laser clad TiC/NiCrBSiC coatings on Ti6Al4V alloys by Finite Element Method. Temperature distribution and dilution rate were obtained. The temperature distributions were sparse and enlarged when laser power increased. With increasing of scanning velocity, the temperature distributions were compressed and lengthened at the front and at the end of the laser beam, respectively. Under laser power P=2.5 kW, scanning velocity V=5 mm/s, the calculated and experimental dilution rates are 6.25% and 8.3%, respectively. There is a good agreement between the results.

Abstract: This paper outlines the development of a 3D finite element model (FEM) for the H13 milling, Deform 3D software was used for ball end milling simulation. A milling force experiment was carried out under the same cutting conditions with the simulation. The results showed that the simulated cutting force agreed well with the experimental data. The proposed method of 3D FEM can be used to correctly simulate the HSM milling process, so as to optimize cutting parameters．

Abstract: By considering the effects of flank milling deformation on machining quality of thin-walled rectangle plate, the flexible force model of spiral end milling is built on the condition that the influence of part/tool on milling is considered with FE (finite element) numerical simulation method in this paper. Based on the flexible force model, the distribution curve of machining deformation is got by the FE prediction for the flank milling of the thin-walled rectangle plate, and the compensation strategy of CL (cutting location) is established. Some contrast tests between the flexible force model, the deflection simulation and error compensation values to the rigid force model and experimental values of flank milling are performed, respectively. The results indicate that both the flexible force model founded in the paper and the analyzed values of flank milling deflection of thin-walled rectangle plate are reliable, and an effective judgment is provided to advance the machining quality of thin-walled parts.

Abstract: The CNC system is a complex mechatronics system, which make it difficult to diagnose fault. Expert system for fault diagnosis that utilizes domain knowledge and the profiles of experts to fix the problem of the complex system has become an important issue. A hybrid expert fault system combining the rule-base reasoning (RBR) with case-based reasoning (CBR) for CNC system is proposed. The combination can trouble-shoot rapidly, improve the CNC system reliability and maintainability. The hybrid system is implemented by using QT and SQLITE database. The experiment result of the system shows that the system diagnosis efficiently and accurately.

Abstract: Involute beveloid gear is one of the involute spur gears .It can be work with parallel axes, intersecting Axes, crossed Axes. Lateral clearance of the gear transmission backlash can be controlled by adjusting the relative axial position of involute beveloid gear transmission pair between two gears. It make a very small backlash or zero backlash .It can be used in backlash-free precision transmission .Its manufacturing is easy and its load capacity and transmission is high. In different cross-section with a different modification coefficient is its geometrical characteristics. The most important par of design involute beveloid gear is to choose a reasonable modification coefficient. In this paper, the beveloid involute gear's design process is introduced to choose its modification coefficient in satisfying various conditions, such as the gear teeth not to undercut, the addendum not to sharpen, guarantees coincidence degree. And uses the VB language to establish a design platform of the external transmission of involute beveloid gear with parallel axes .It is suit for project application. First，chooses modification coefficient by not to undercut, not to sharpen, guarantees coincidence degree.Next, compute the related geometry size. Third, according to the computed result, draws up the tooth profile curve in SolidWorks. Thus produces the gear's tooth profile or the socket gallery precisely, make gear's 3D modeling. It provides the basis for gear's optimization design and advanced manufacture. A new gear is rapidly established by change gear parameter in the designs platform. It can greatly raises r the efficiency and the precision of design involute beveloid gear, which provided the precise model for its dynamic simulation, the NC processing, the interference examination as well as the finite element analysis. Introduce the use method of design platform through a practical example confirms its usability.

Abstract: A virtual measurement system for geometric surfaces of some specific mechanical components was created with Cage Method and Virtual Probe technique based on Three Model Method. The fundamental constituents of the system, the key part of the Three model Method, measured model, were presented in detail with weighed random number technique. Measuring accuracy may properly be controlled by alteration of the number of sampling points of the measured model. Principle of the measuring system, with extendable function, was put forward and explained. The system was operated by VC++ and OpenGL with characteristics of lifelike, function-extension, and immersion. Virtual measurement on a bar-shaft for cylindricalness is given as an example, and it has been shown that the results have much good agreement with those of experiments and that the system worked stably.

Abstract: In this paper the implementation procedure of Human Head curve reconstitution has been investigated and the curve reconstitution model has been built based on reverse engineering and pre-processing theory of data-points. The data acquisition of head curve was implemented by means of the laser scan system. The data-points were disposed, and the head curve was reconstructed, and the error and smoothness were analyzed by means of high-end CAD / CAE / CAM software CATIA V5. Those laid the foundation for late further research surface reconstruction.

Abstract: This paper adopts semi-analytical finite cylindrical shell element method to research the local stability of buried stiffened-penstock, and considering the influence from initial interstice and stiffener ring. Displacement model of cylindrical shell element is established, elastic stiffness matrix and geometric stiffness matrix of the element is deduced, in the process of deducing formula, using sectional suppose and result which is adopted in the process of deducing Amstutz formula. Calculation results show that, Calculating local stability of buried stiffened-penstock by semi-analytical finite cylindrical shell element method has good convergence. This paper provides an new method for local stability analysis of buried stiffened-penstock.

Abstract: The aim of this research is to design and fabricate the machine for production of bio-oil from agricultural residues in northeast of Thailand. Experiment: to produce the bio-oil from corn-stalk, husk and sawdust with 200 g/hr of capacity, 500°C of reactor temperature, -10°C of condensing unit temperature and testing of the mechanics and chemical property. The results showed that the yield of bio-oil from corn-stalk husk and sawdust are 17.40 18.40 and 22.40, respectively. According to the physical characterisation of the products, it was found that the bio-oil produced in this work showed similar properties to the bio-oil from commercial production. The results found in this research are useful for the development of a larger-scale bio-oil production unit, which is an on-going project at the Faculty of Engineering, Maha Sarakham University.