Papers by Keyword: Levitation

Abstract: This paper presents a new transformative manufacturing methodology for free-form machining. An experimental prototype machine is constructed to levitate and rotate an object attached with sharp edges, which act as a cutter for the purpose of performing machining processes. This device aims to lead to a technological breakthrough, overcoming the limitation of the workpiece features, and achieve greater free-form machining capability. The construction of curved holes and interior surfaces are constrained by the geometry of the machine tool. The proposed concept creates a new device that uses a magnetic field generator as a base. It is loaded with a constant power imposing a vertical physical force to balance gravity and stabilize the cutting tool. With the uniqueness of a preferred orientation between the tool and the base, a rotating surface placed below the base permits the rotation of the cutting tool in order to achieve desired tool rotation speed. A smooth and controlled cut is achieved on a soft material. The result shows the feasibility of the device to achieve similar outcomes as a machine tool.

Abstract: Voice coil motor is an electromagnetic actuator widely used for motion generation. The main weakness of a voice coil motor is small force. In this paper a voice coil motor is mathematically modeled, analyzed and optimized to obtain high force. According to the optimized final designs, the performance of the voice coil motor is evaluated.

Abstract: Magnetic suspension type belt conveyor used magnetic machinery technology design can solve the belt conveyor of roller support parts number, large energy consumption and high maintenance cost, limited tape speed, large noise and other issues. Magnetic belt conveyor design is the key to stability analysis of the operation of conveyor belt. Papers from a mechanical point of view to study the structural stability calculation. The results show that small interfering in the external magnetic conveyor belt, the permanent support system can be adjusted to spontaneously stable equilibrium state.

Abstract: The Ni-4at%W alloys was prepared with cold crucible levitation, subsequent levitation re-melting and high pressure torsion (HPT) intensive deformation. In samples after levitation precipitates of Ni4W phase as well as grain boundary continuous phase were formed. Levitation re-melting resulted in partial dissolution of the precipitates, increasing W content in the matrix and lead to the microstructure refinement. The deformation by HPT, in the range of 300-400%, lead to the lead to the homogenization of the solid solution and partial decomposition of the alloys into pure Ni and W. In the homogenous majority of the sample the microstructure transformed from dendrite microstructure to faceted grains. The analysis of the grains sizes and shapes showed that the average grain size in the sample re-melted by levitation was twice the grain size of the sample only prepared with CCLM. Also, the grains in this sample were elongated by 50-60% in one direction, while in the sample prepared by CCLM they were equiaxial. As the nominal composition of the alloys in both cases was the same, differences observed in the microstructure after re-melting and HPT processing must result only from the differences in the cooling rate leading to small differences in W content in solid solution and phase composition after solidification. High rate of cooling in the levitation methods resulted in Ni4W metastable phase precipitation as well as in the refinement of the microstructure, stronger after additional re-melting of the alloy by levitation.

Abstract: Solidification processes of Fe-B and Fe-C eutectic alloys have been investigated by a time-resolved synchrotron x-ray diffraction under containerless cooling conditions using a conical nozzle levitation technique. To observe relative variations of structure from the undercooled liquid to crystalline phase, we have conducted millisecond order time-resolved x-ray diffraction experiments with a two-dimensional detector. The structural variations observed during the solidification of the Fe₈₃C₁₇ alloy were identified as the phase transformation process expected from the Fe-C phase diagram. As for the Fe₈₃B₁₇ alloy, it was revealed that a metastable phase composed of Fe₂₃B₆ compound was precipitated as a primary crystalline phase from the undercooled liquid. In addition, decomposition of the metastable Fe₂₃B₆ phase showed dependence on the cooling rate of the sample. At the cooling rate of 30 K/s, the Fe₂₃B₆ phase decomposed to bcc-Fe and Fe₂B phases with decreasing temperature. On the contrary, at the cooling rate of 180 K/s, the metastable Fe₂₃B₆ phase remained in spite of an appearance of the bcc-Fe phase. By comparing the primary crystalline phase between the Fe₈₃C₁₇ and the Fe₈₃B₁₇ alloys, we suggest that the formability of the metastable Cr₂₃C₆-type compound is closely related with the glass-forming ability of Fe-metalloid binary alloys.

Abstract: This paper presents the design of a novel superconducting levitated module for UAQ4 train whose feasibility has been successfully tested and confirmed in laboratory. The work concept of self-balancing “V” shaped levitation module is described and the results of levitation tests performed using a measurement set up are discussed. Lastly the levitation module performances are also carried out using numerical finite element analyses by varying the sideslip angle of the module and work system configuration.

Abstract: It is well known that multi-component alloys form bulk metallic glasses (BMGs) from the supercooled liquid state without rapid quenching. However, the mechanism of phase selection between crystal and glass states has not been fully clarified. To obtain an insight into the glass-forming processes, we carried out in-situ observation on the solidification of Zr-based BMG-forming alloys from its supercooled liquids by time-resolved X-ray diffraction combined with the conical nozzle levitation (CNL) technique to achieve a containerless melting. For Zr-based alloys, we succeeded in detecting the X-ray diffraction patterns during glass formation from the supercooled liquid state as well as the crystallization from the liquid state. Furthermore we performed the precise structure analysis of supercooled state of Zr-based binary liquids. Based on the liquid structure and in-situ observation results, we discussed about the phase selection mechanism between crystal and glass states.

Abstract: The purpose of this paper is to investigate principles of levitation and restitution of blowing nozzle prior to fabricating a prototype of air handling system. Since air force distributions streaming bottom surface of a flat panel display (FPD) highly dependent on operating as well as design condition and configuration of air handling system, influences of various parameters such as flow rate, supply air pressure, floating height and tilted angle are examined through a series of computational fluid dynamics (CFD) analyses. Moreover, dynamic finite element analyses of the FPD are carried out to assure that an oscillation effect caused by disturbances is not significant. Key findings from the both CFD and structural analysis results are presented and discussed, which can be utilized as technical bases for development of the practical air handling system.

Abstract: A novel synthesis procedure of multifunctional Ti based alloy was suggested under containerless processing using an electromagnetic levitation furnace. In this method, necessary condition to synthesize the alloys with ability of a dislocation-free plastic deformation was determined. That was supported by microstructural observation, hardness measurement and X-ray analysis of the alloys solidified from several undercoolings. The maximum undercooling of the alloy melt was up to 120K. Synthesized alloys that met the condition showed refined microstructures, increase of d-value of (110) plane and a tiny deviation of hardness by cold-working Others partially occurred stress-induced transformation.