Advanced Materials Research Vols. 328-330

Abstract: This paper reviews two cooling methods for surface grinding. These include i) replacing the toxic coolant by a mixture of cold air and vegetable oil mist, and ii) minimising the use of coolant using a segmented grinding wheel system. The discussion concludes that the cold air-oil mist provides an environmentally conscious mean for surface grinding. However, due to the limit of its cooling capacity, it is more applicable for fine grinding. Using the segmented wheel system can minimise coolant consumption and can improve grindability.

Abstract: Thermodynamic properties of water during phase transition in fractured rock are discussed. Thermodynamic equations of water in fractured rock while freezing were analyzed, and an example was simulated by FLAC3D. The stress field as well as the temperature field is obtained. The results demonstrated mechanical and thermal influences on rock due to phase transition of water in fractures.

Abstract: In order to improve the performance of back drawing type of flexible multi-gripper stretch forming machine used for double-curvature metal sheet forming, back and down drawing type of flexible multi-gripper stretch forming machine was designed by finite element method (FEM), which has simple structure and cheap cost. The FE model of flexible multi-gripper stretch forming was established, and extensive numerical simulations of spherical parts for two kinds of flexible stretch forming machines were carried out. The variations of stress, strain, thickness and springback value of spherical parts for two kinds of drawing modes were analyzed. The numerical results show that the quality of spherical parts formed by the back and down drawing type of stretch forming machine is better than that by the back drawing type of stretch forming machine. This work provides a machine for developing the technology of stretch forming.

Abstract: Tools of tunnel boring machine CAD models have been built by CAD software, it is analyzed static characteristics and fatigue characteristics by finite element analysis and obtaining the displacement in the poor stiffness conditions. Improving its structure to strengthen stiffness and fatigue life by the calculate result. The final result shows that the structure can satisfy its rigid command and can fit the soil conditions above 5%-10%. Damage frequency of tools is greatly deduced. It provides a theoretical basis for the actual design and product manufacturing.

Abstract: Miniature heat pipe is one of promising means of removing high heat flux for electronics cooling in limited available space. How to produce narrow and deep microcapillary grooves is the critical issue in promoting performance of axially grooved miniature heat pipe. In this work, the microcapillary grooves for miniature cylindrical heat pipe was fabricated by using oil-filled high speed spinning method. The forming process of microcapillary grooves was investigated. The influence of technical parameters on characteristics of microcapillary grooves was analyzed and the optimal technical parameters were found out. The experimental results show that drawing speed ranging from 48cm/min to 64cm/min, spinning ball number of 4 and big distance between the end of multi-tooth mandrel and the center of spinning balls within 3.7 mm should be chosen to obtain narrow and deep microcapillary grooves. In addition, the forming mechanism was investigated by observing microstructure of cross-section of microcapillary grooved tubes.

Abstract: Vibration-assisted machining (VAM) combines small-amplitude vibration with different machining process to improve the process fabrication quality. It has been applied to a number of machining processes, such as turning, drilling, grinding and polishing. The emphasis on this literature is the vibration-assisted abrasive machining (VAAM), which involves with finishing and grinding processes where VAAM have been applied to hard metal, brittle material and complex geometries products like optical molds. This paper presents different vibrating units in VAAM from tool vibration to workpiece vibration, which also includes different vibrating paths from linear to ellipse. Typical hardware systems used to achieve these vibratory motions are described too.

Abstract: In practice a MOSFET is anti-parallel with a diode. In the paper there is a method how to build its model. The model applies for the MOSFET works as a power switch. The model consists of two capacitors, a voltage-controlled switch and a diode. There is an example for the model building. The circuits including the model are simulated. The results prove that the electrical data of model equals basically its actual data. The model can help electrical engineers design circuits which uses MOSFET as a power switch. The model built only need the data of its manual. The merit is very suitable for electrical engineers.

Abstract: The rotor of claw-pole permanent magnet generator is constructed by two flangeHs with claw and a ringH of Nd-Fe-B permanent magnet magnetized axially,H axial fluxH is transformedH effectiveH radial fluxH, the polarityH of adjacent claw-poles is opposite, N poles and S poles array alternately. Based on design theory of permanent magnet generator, major parametersH of generator is determineHd. Using equivalent magnetic circuit method, the magnetic path of generator is analyzed, permeance and flux are calculated, thus the claw-pole permanent magnet generator is designed, it possesses high reliability, simple processH and effective voltage-stabilized characteristic.

Abstract: Combining with the actual production case, a multi-objective optimization rescheduling problem about that multiple products with various manufacturing processes in auto-production line aiming at a single hoist production in sequence where a new product is inserted is studied. Mathematical model and algorithm with a new stochastic scheduling method are proposed in fully consideration of the equipment (tank) and constraint of manufacture process. The model and algorithm which have been used in auto-production line of a surface treatment over half a year can meet the practical production requirements.