Formation Mechanism of Grain Cutting Edges in Micro Dressing of Polycrystalline cBN Grinding Wheels

2012 ◽  
Vol 523-524 ◽  
pp. 137-142 ◽  
Author(s):  
Yoshio Ichida
Keyword(s):  
Flat Surface ◽  
Coarse Grain ◽  
Grinding Wheels ◽  
Wheel Surface ◽  
Dressing Method ◽  
Diamond Cutting ◽  
Flat Surfaces ◽  
Fine Grain ◽  
Working Surface ◽  
Ductile Removal

This paper presents a mechanism for the formation of grain cutting edges in the micro dressing of coarse-grain polycrystalline cubic boron nitrite (cBN) grinding wheels using a fine-grain diamond dresser. Many grain cutting edges having a flat surface consisting of ductile smooth surfaces as well as many brittle micro dents, are formed on the working surface of the coarse-grain (#80 mesh) cBN wheel by micro dressing using a fine-grain (#1200 mesh) diamond dresser. This result shows that the flat surfaces of cutting edges on the wheel surface are formed on the basis of a ductile removal process as well as a brittle micro-fracturing of cBN grains by the diamond cutting edges. Moreover, cylindrical grinding experiments with these wheel working surfaces were conducted to clarify the feasibilyty of creating a ground mirror-like surface. As a result, it was confirmed that high-quality mirror surfaces with roughness less than 0.03 m Ra can be efficiently formed using the working surface prepared by this micro dressing method.

Fabrication of Porous Metal Bonded Diamond Grinding Wheels for Flat-Surface Nanomachining

MRS Bulletin ◽  
2001 ◽  
Vol 26 (7) ◽  
pp. 544-546 ◽  
Author(s):  
Koji Matsumaru ◽  
Atsushi Takata
Keyword(s):  
Flat Surface ◽  
Porous Metal ◽  
Small Scale ◽  
Grinding Wheels ◽  
Related Area ◽  
Flat Surfaces ◽  
Diamond Grinding ◽  
The Creation

The articles thus far in this MRS Bulletin issue on Emerging Methods for Micro- and Nanofabrication have addressed the creation of structures or devices on a small scale. What is implicit in some of these articles is that a substrate of sufficient flatness is available upon which to build these structures in a controlled way. A related area, therefore, is the formation of these flat surfaces, as well as the development of the tools to make them.

Dressing Technology on the Diamond Abrasive Grinding Wheels Using the Rotary Diamond Dresser

2009 ◽  
Vol 416 ◽  
pp. 234-237
Author(s):  
Zhong Ming Cui ◽  
Peng Hui Deng ◽  
Lei Du
Keyword(s):  
Single Point ◽  
Grinding Wheels ◽  
Dressing Method ◽  
Diamond Tools ◽  
Diamond Grinding ◽  
Dressing Tool ◽  
Dressing Force ◽  
Diamond Abrasive ◽  
Better Than

The dressing processes are conducted on the diamond grinding wheels using the rotary diamond tools and compared between the single point diamond dresser and the rotary diamond dressing tool in the following aspects, including the dressing force, tool wearing, dressing efficiency. The result shows that, the dressing performance of the rotary diamond tools is remarkable better than that of the conventional dressing method.

Analysis of Cracking Process in Conditions of High-Temperature Creep of Castings Form the Modified Superalloy IN-713C

2013 ◽  
Vol 212 ◽  
pp. 247-254
Author(s):  
Marek Cieśla ◽  
Franciszek Binczyk ◽  
Marcin Mańka
Keyword(s):  
High Temperature ◽  
Creep Resistance ◽  
Nickel Superalloy ◽  
Morphological Properties ◽  
Coarse Grain ◽  
High Temperature Creep ◽  
Temperature Creep ◽  
Fine Grain ◽  
Initiation And Propagation ◽  
Cracking Process

mpact of complex modification and filtration during pouring into moulds on durability has been evaluated in this study in conditions of high-temperature creep of castings made from nickel superalloy IN-713C post production rejects. The conditions of initiation and propagation of cracks in the specimens were analysed with consideration of morphological properties of material macro-, micro-and substructure. It has been demonstrated that in conditions of high-temperature creep at temperature 980°C with stress σ =150 MPa creep resistance of the IN-713C superalloy increases significantly with the increase of macrograin size. Creep resistance of specimens made of coarse grain material was significantly higher than the resistance of fine grain material.

scholarly journals Constraining the Age of Floodplain Levels Along the Lower Section of River Tisza, Hungary

2016 ◽  
Vol 9 (1-2) ◽  
pp. 39-44 ◽  
Author(s):  
György Sipos ◽  
Tímea Kiss ◽  
Orsolya Tóth
Keyword(s):  
Flood Plain ◽  
Luminescence Dating ◽  
Coarse Grain ◽  
Lower Section ◽  
Vegetation Control ◽  
Fine Grain ◽  
Energy Environment ◽  
The Given ◽  
Luminescence Characteristics ◽  
Grain Size Fractions

Abstract During the Late Pelistocene-Holocene transition the fluvial landscape of the Great Hungarian Plain changed considerably as a consequence of tectonic, climatic and geomorphological factors. Geochronology, and especially luminescence dating, is a very important tool in reconstructing these changes. The present study focuses on the Lower-Tisza region and addresses the timing of the development of different floodplain levels. In the meantime the luminescence characteristics of the investigated alluvial sediments were also assessed, with a special emphasis on the comparison of silty fine grain and sandy coarse grain results, as in the given medium and low energy environment fine grain sediments are more abundant, however, based on the literature, coarse grain samples are more reliable in terms of luminescence dating. Measurements were performed on 12 samples originating from the point bars of two large palaeo-meanders, representing different floodplain levels along the river. Results indicate the applicability of both grain size fractions for dating purposes, though fine grain subsamples overestimate in average by 1.5 ka the ages yielded by coarse grain subsamples. Consequently, fine grain samples can be used for outlining only general trends, and results need to be controlled by coarse grain measurements where possible. Based on the ages received, the upper floodplain was actively formed until 13-15 ka, when incision and the development of an intermediate floodplain level started. The meander on the intermediate flood plain level developed then very actively until 9 ka. As indicated by the received age information the intensity of meander formation could be highly affected by climatic and especially vegetation control. However, reconstruction can be refined later by further sampling and the application of the results of the present paper.

scholarly journals Formation of Residual Stresses during Discontinuous Friction Treatment

2021 ◽  
Vol 8 (1) ◽  
pp. C38-C44
Author(s):  
I. Hurey ◽  
V. Gurey ◽  
M. Bartoszuk ◽  
T. Hurey
Keyword(s):  
Grain Size ◽  
Residual Stresses ◽  
Mineral Oil ◽  
Surface Shape ◽  
Technological Medium ◽  
Flat Surfaces ◽  
Compressive Stresses ◽  
Friction Treatment ◽  
Working Surface ◽  
Pass Through

The tool with grooves on its working surface is used to improve the properties of the strengthened layer. This allows us to reduce the structure’s grain size and increase the thickness of the layer and its hardness. Mineral oil and mineral oil with active additives containing polymers are used as a technological medium during friction treatment. It is shown that the technological medium used during the friction treatment affects the nature of the residual stresses’ distribution. Thus, when using mineral oil with active additives containing polymers, residual compressive stresses are more significant in magnitude and depth than when treating mineral oil. The nature of the residual stresses diagram depends on the treated surface’ shape. After friction treatment of cylindrical surfaces, the highest compressive stresses near the treated surface decreases with depth. And after friction treatment of flat surfaces near the treated surface, the compressive stresses are small. They increase with depth, pass through the maximum, and then decrease to the original values. The technological medium used during friction treatment affects residual stresses in the grains and in the crystal lattice.

scholarly journals The Effect of Nonequilibrium Structure State on the Creep and Superplastic Behaviour of Materials

2008 ◽  
Vol 575-578 ◽  
pp. 1031-1037
Author(s):  
M.M. Myshlyaev
Keyword(s):  
Mechanical Behaviour ◽  
Coarse Grain ◽  
Zinc Alloy ◽  
Cobalt Alloy ◽  
Superplastic Behaviour ◽  
Fine Grain ◽  
Grain Zinc ◽  
Nonequilibrium Structure ◽  
Structure State ◽  
Kinetic Principle

Mechanical behaviour at creep and superplasticity of coarse grain and monocrystalline aluminum under torsion, of coarse grain molybdenum, of fine grain zinc alloy and amorphous cobalt alloy under tension are discussed from unified positions. It is shown that realization of their superplasticity requires fulfillment of structure-kinetic principle.

Microstructure Evolution of Copper by Three Roll Planetary Milling

2018 ◽  
Vol 279 ◽  
pp. 44-48 ◽  
Author(s):  
Yu Wei Zhou ◽  
Ze Ning Mao ◽  
Ying Liu ◽  
Jing Tao Wang
Keyword(s):  
Dynamic Recrystallization ◽  
Pure Copper ◽  
Milling Process ◽  
Planetary Mill ◽  
Grain Structure ◽  
Coarse Grain ◽  
Engineering Strain ◽  
Fine Grain ◽  
Equiaxed Grains ◽  
Equiaxed Grain

The microstructure of commercial pure copper TP2 tube by three roll planetary mill processing was investigated. Due to work hardening and subsequent softing by dynamic recrystallization during milling process,the coarse grain structure of the copper transformed to fine grain structure. The grain refinement is achieved along the axial moving in general; in the reducing zone, the sample has a gradient structure along the radial direction; uniform equiaxed grain with size of ~2 μm could be obtained at the outlet. The initiation of dynamic recrystallization occurred in the three roll planetary mill the reduction engineering strain reach ~30%, where some equiaxed grains replaced the elongated grains because of recrystallization.

Small theropod and bird teeth from the late Cretaceous (late Campanian) Judith River Group, Alberta

2002 ◽  
Vol 76 (4) ◽  
pp. 751-763 ◽  
Author(s):  
Julia T. Sankey ◽  
Donald B. Brinkman ◽  
Merrilee Guenther ◽  
Philip J. Currie
Keyword(s):  
Late Cretaceous ◽  
Flat Surface ◽  
Flat Surfaces ◽  
Wear Pattern ◽  
A Share

A collection of over 1,700 small theropod teeth from the Judith River Group (Campanian;˜79.5–74 Ma) allows our understanding of the diversity and variation of small theropods in this assemblage to be refined. In addition to the previously recognized taxa, a series of morphologically distinct groups are recognized that may represent distinct taxa in some cases. Teeth with the Paronychodon-like features of a flat surface with longitudinal ridges on one side are resolved into a few discrete morphotypes. Two of these are included in Paronychodon lacustris and two additional morphotypes are hypothesized to represent distinct taxa, here referred to as ?Dromaeosaurus morphotype A and Genus and species indet. A. The teeth of Paronychodon lacustris and ?Dromaeosaurus morphotype A share a distinctive wear pattern that suggests tooth functioning involved contact between the flat surfaces of opposing teeth. Two species of Richardoestesia, R. gilmorei and R. isosceles, are present in the assemblage. Additionally, bird teeth are identified in the assemblage and are described in this review.Bivariate plots were used to document the variation in the theropod teeth, especially in the features that distinguish between Richardoestesia gilmorei, R. isosceles, Saurornitholestes, and Dromaeosaurus. Considerable overlap is present in all plots, so although the teeth are morphologically distinct, they are not easily distinguished by quantitative means.

Design and Fabrication of the Superabrasive Grinding Wheel with Phyllotactic Pattern

2012 ◽  
Vol 472-475 ◽  
pp. 2354-2360 ◽  
Author(s):  
Yu Shan Lu ◽  
Cheng Yi Zhao ◽  
Jun Wang ◽  
Yan He ◽  
Zhi Hui Kou
Keyword(s):  
Experimental Results ◽  
Grinding Wheel ◽  
Wheel Surface ◽  
Work Surface ◽  
Phyllotactic Pattern ◽  
Uv Lithography ◽  
Working Surface ◽  
Abrasive Grain ◽  
Grinding Performance ◽  
Cluster Pattern

In order to achieve the controllability of the abrasive arrangement on the working surface of grinding wheel,a new kind of the superabrasive grinding wheel, which has defined abrasive grain cluster pattern, has been designed based on the phyllotaxis theory of biology, and fabricated with UV lithography method and electroplating technology. The analytical results indicate that the phyllotactic parameters influence on the abrasive arrangement configuration on the work surface of the superabrasive grinding wheel, so as to improve grinding performance of the grinding wheel, increasing the diameter of phyllotactic abrasive grain cluster and decreasing phyllotactic coefficient can increases the abrasive grain density of the surperabrasive grinding wheel surface. Electroplating experimental results show that the reasonable electroplating processes can reduce the faults of defined abrasive arrangement on the superabrasive grinding wheel surface.

scholarly journals Designing bioinspired surfaces for water collection from fog

2018 ◽  
Vol 377 (2138) ◽  
pp. 20180269 ◽  
Author(s):  
Dev Gurera ◽  
Bharat Bhushan
Keyword(s):  
Flat Surface ◽  
Unit Area ◽  
Water Repellency ◽  
Vertical Axis ◽  
Collection Rate ◽  
Flat Surfaces ◽  
Single Cone ◽  
Water Collection ◽  
The Difference ◽  
Conical Surfaces

A systematic study is presented on various water collectors, bioinspired by desert beetles, desert grass and cacti. Three water collecting mechanisms including heterogeneous wettability, grooved surfaces, and Laplace pressure gradient, were investigated on flat, cylindrical, conical surfaces, and conical array. It is found that higher water repellency in flat surfaces results in higher water collection rate and inclination angle (with respect to the vertical axis) has little effect. Surfaces with heterogeneous wettability have higher water collection rate than surfaces with homogeneous wettability. Both cylindrical and conical surfaces resulted in comparable water collection rate. However, only the cone transported the water droplets to its base. Heterogeneity, higher inclination and grooves increased the water collection rate. A cone has a higher collection rate per unit area than a flat surface with the same wettability. An array of cones has higher collection rate per unit area than a single cone, because droplets in a conical array coalesce, leading to higher frequency of droplets falling. Adding heterogeneity further increases the difference. Based on the findings, scaled-up designs of beetle-, grass- and cactus-inspired surfaces and nets are presented. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology’.

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