Advanced Materials Research Vol. 670

Abstract: Facing the abundant service resources, how to make the heterogeneous distributed resources information system has the meaning that can be understand between man-machine and machines, search conveniently and implement the resources integration, achieve information access and query better as well as the interoperability between systems, it is a challenge it faces which implementing the resources sharing and intelligence services, but also a problem which to improve the service informatization level for RM industries to be solved. To facility services resource sharing in Rapid Manufacturing (RM) industry, mainly discussed demand analysis and establishment principle of RM domain ontology. Based on the many years of experience and enterprise instances, domain ontology was described conceptual and expressed knowledgeable and model structure was established. The knowledge representation method is adopted based on the domain ontology query model and partial examples of service description are given. In order to solve semantic fuzziness and realize integration, interoperability and reusability of enterprise service by building domain ontology which can satisfy shared understanding of interested parties. On this basis, integrated service system architecture was designed to support resource sharing. The methods had been applied preliminarily and would provide the basis for the future work and extended field.

Abstract: Three NiCoCrAlY cladded coatings reinforced by different contents of nano- Al2O3p and one without nano-Al2O3p were prepared on a Ni-base super alloy using laser cladding technique. Hot corrosion of the NiCoCrAlY coatings in Na2SO4/K2SO4 (75:25, wt. /wt.) mixture was performed at 1050 °C in static air. The effects and influencing mechanism of nano-Al2O3p on the hot corrosion behavior of the coatings were discussed. Results indicate that the hot corrosion resistance of the coatings with nano-Al2O3p is better than that of the one without nano-Al2O3p, among which the one with 1.0 wt. % nano-Al2O3p presented the best hot corrosion resistance. The improvement of the hot corrosion resistance is largely due to the refinement of the microstructure after adding nano-Al2O3p.

Abstract: By using experiment cutter edge topography obtained by super depth three-dimension microscope, fits the cutter edge curve and calculate experiment cutter edge radius value; by high speed milling hardened steel experiment, individually researches cutter edge and cutting parameters influence on machined surface in high speed milling hardened steel with end-milling cutter and ball-end milling cutter. The experiment analysis results show that under the same cutting parameters condition, machined surface roughness in high speed end-milling cutter milling is better than in high speed ball-end milling; within experiment selected cutting parameter range, cutter edge radius is the main influence factor on machined surface roughness in high speed end- milling hardened steel, while the influence on machined surface roughness in high speed ball-end milling hardened steel is not obvious. In end-milling, when edge radius and milling depth are in the same order magnitude or the difference is not obvious, milling depth should be a little bigger than selected cutter edge radius value.

Abstract: The three-dimensional models of the Working-roll of Carder are founded by three-dimensional design software Solidworks and the working process of Working-rolls is simulated by finite element analysis software Cosmos, which obtain overall stress distribution for the Working-roll of Carder. The relations between the working-rolls with different thickness and different length of work roll axis and the stress, strain and radial displacement in the working process of working-rolls are attained by finite element analysis and the important factors of impact of work roll deformation are indicated by analog simulation. The results show that the maximum stress and maximum strain are occur in the place of roller connected with the axis rather than to appear in the middle part of roller and the radial displacement in the working process of working-rolls and the length of work roll axis are not directly relationship. The Finite element analysis results provide an important theoretical basis to design a reasonable the length of axis and the thickness of roller for the working-roll of carder.

Abstract: This paper presents an operator that fitting the parameters of ellipses features, and improves the computational efficiency. Based on the dual conic model, this operator directly uses the raw gradient information in the neighborhood of an ellipse’s boundary, which use tangent lines and to apply the estimation in the dual space, so that avoiding the step of precisely extracting individual edge points. Moreover, under the dual representation, the dual conic can easily be constrained to a dual ellipse when minimizing the algebraic distance. The operator presents low sensitivity to noise and is compared to other estimation approaches, which shows good results, the accuracy of this operator is the highest, the time of this operator is moderate that compared with the other methods, and fall within acceptable levels, and in the case of noise or blur, the algorithm have shown very good robustness, in the practical environment can fit the parameters of the ellipse accurately.

Abstract: Cold rolling is an advanced splinterless processing method, which has been applied to process many parts, like spur gears, helical gears, spline shaft and ballscrew, etc. Ballscrew which determines the motion characteristics has been used as key transmission part of ballscrew pair. According to differential geometry and meshing theory, the mathematic model of ballscrew manufactured by cold rolling is built, and the normal section equation of ballscrew is derivated in this paper. The cold forming principle of ballscrew is investigated; the meshing model, the contact line and theoretical errors of the ballscrew are constructed. The objective moving laws between roller and workpiece are revealed by analyzing the meshing model and the contact line, the processing method of cold-rolling is considered as the generating method which can lay the foundation for roller design by analyzing forming principle. By analyzing the profile error and the error of the actual helix of the centrode of ball, the error generation causes are discovered, and the calculation methods of the profile error and the spiral error of ballscrew are proposed. By analyzing the error evolution and taking a certain type of ballscrew for example, the results indicate that the profile error is brought by roller designing, and the spiral error is caused by discontinuous contact.

Abstract: In order to treat the performance of nano-electro-mechanical (NEM) switches in low vacuum, molecular dynamics model of NEM switches is established and the influence of air damping on NEM switches is investigated. When the pressure in low vacuum is from 100Pa to 1000Pa, we get the gas molecule in low vacuum belong to free molecule flow. Tersoff-Brenner potential function is used to describe the interaction of carbon nanotube atoms. L-J potential function is adopted to state the interaction between carbon nanotube and the base ground. Results show that in low vacuum condition, when the same amplitude change of intensity of pressure, the lower intensity of pressure change will take a more clearly effect for the nano structure than the higher intensity of pressure change. Results also show when the length of carbon nanotube from 200 circles to 50 circles, the beam vibrating amplitude increased gradually. When the length is 50 circles, the vibrating amplitude reach the maximum. With the beam length keep to decrease, the vibrating amplitude becomes weak crossly.

Abstract: Metal magnetic memory testing (MMMT) technique is a kind of new NDT technique. It is interested by NDT area in recent years for its own advantages: early diagnosis, preventing sudden fatigue failure of equipments and the testing samples do not need to be magnetized. In order to find out the variation law of the residual magnetic strength of ferromagnetic material processed by different cutting method, axial tension tests about milling and flat surface grinding samples are completed in elastic and plastic deformation phase. The experimental results indicate that the magnetic strength variation law of two kinds of sample makes a great difference in the same deformation phase. The magnetic strength and standard deviation variation law of the grinding and milling samples are almost reverse. But there is a common ground of the two samples that when the material reaches yield phase, turning point occurs on both the residual magnetic strength and standard deviation curve. So we can identify whether there is plastic deformation according to the residual magnetic strength variation law of ferromagnetic material.

Abstract: Generally, pressures resulted from roller during leveling process in selective laser sintering has the effect of densification of powder materials. But extra frictions due to them become the forces which always deteriorate the surface of the part and mark it with several lines trace. Sometimes, the manufacturing can even not continue if these forces accumulate to a large extent to move the whole part. Therefore, the whole forming process will be obliged to stop owing to the displacement of part from above mentioned damage. In this work, the emerging reason and related variation factors of these forces were studied mathematically, the mathematical and physical model of friction force was also built to describe the connections between the leveling process parameters and them. How to control the influence factor of friction to abate their damages to surfaces and promote the forming quality were also discussed based on these models. This will provide a common reference for the application of selective laser sintering technology.

Abstract: A novel material synthesis technique, microwave process was investigated for the production of phosphor powders. In this study, we have developed a new method to product phosphor powders, and applied this process into one materials fabrication. EuDL3 where L is cinnamic acid (C6H5CH = CHCOOH, HL), D = 2, 2' – Bipyridine (bipy) phosphor powders were successfully synthesized by microwave process. The process takes only 24 min to obtain phosphor powders. The resultant phosphor powders were investigated by TG – DTA, IR, luminescence spectroscopy, and scanning electron microscope (SEM).