An Investigation of Grinding Wheel Cutting Edges

1964 ◽  
Vol 86 (4) ◽  
pp. 371-382 ◽  
Author(s):  
H. Tsuwa
Keyword(s):  
Electron Microscope ◽  
Microscopic Observation ◽  
Phase Contrast ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Abrasive Grains ◽  
Contrast Microscope ◽  
New Apparatus ◽  
Grinding Operations ◽  
Dressing Action

A new apparatus for microscopic observation and tracing of cutting edges of a wheel has been developed. The use of this apparatus allows us to visually witness the behavior of abrasive grains during the grinding operation. A phase-contrast microscope, as well as an electron microscope has been used with the new apparatus in this investigation. A method of calculating effective grain spacing to show distribution of cutting edges, as well as the cutting edge ratio to known worn conditions of grains has been completed. These aforementioned values for various grinding wheels have been studied in grinding operations and the changing aspects of them have been noted. Through these experiments, we have had helpful suggestions about grinding mechanisms; there is no self-dressing action of grains in the usual grinding work; sliding of the cutting edges takes place in the grinding, and wear of the grinding is increased by this action.

scholarly journals Theoretical considerations of machining with grinding wheels

2013 ◽  
Vol 2 (2) ◽  
pp. 126 ◽  
Author(s):  
Andrew Oyakhobo Odior ◽  
Festus A Oyawale ◽  
Sunday O. Oyedepo ◽  
Samson A Aasa
Keyword(s):  
Radial Force ◽  
Grinding Wheel ◽  
Work Piece ◽  
Grinding Wheels ◽  
Abrasive Particles ◽  
Abrasive Grains ◽  
Grinding Parameters ◽  
Machine Parts ◽  
Grinding Operations ◽  
Theoretical Considerations

Grinding is one of the most versatile methods of removing material from machine parts by the cutting action of the countless hard and sharp abrasive particles of a revolving grinding wheel. It works by forcing the abrasive grains into the surface of the workpiece so that each grain cuts away a small bit of material in the form of chips. Abrasive grinding wheel is an expendable wheel that carries an abrasive compound on its periphery. They are made of small, sharp and very hard natural or synthetic abrasive minerals, bonded together in a matrix to form a wheel. The paper presents a review of some of the characteristics as well as theoretical considerations of operations of abrasive grinding wheel. The relationships among the various grinding parameters; the radial force f, the force on individual grit of grinding wheel F, velocity of grinding wheelg Vg, velocity of work piecew Vw, the wheel diameterg Dg, and the diameter of the work piece Dw were established for given grinding operations.

Methodology for Evaluation of Treated Steels and Alloys in Abrasive Processing

2021 ◽  
Vol 410 ◽  
pp. 262-268
Author(s):  
Vyacheslav M. Shumyacher ◽  
Sergey A. Kryukov ◽  
Natal'ya V. Baidakova
Keyword(s):  
Physical And Mechanical Properties ◽  
Metals And Alloys ◽  
Grinding Wheel ◽  
Measuring Instruments ◽  
Abrasive Machining ◽  
Machining Performance ◽  
Abrasive Grains ◽  
Abrasive Tools ◽  
Composition Structure ◽  
Grinding Operations

One of the critical physical and mechanical properties of metals and alloys is the suitability for abrasive machining. Machining by abrasive tools is the final operation that sets the desired macro-geometry parameters of processed blanks and microgeometry parameters of processed surfaces such as roughness and length of a bearing surface. Abrasive machining determines the most important physical and mechanical parameters of a blank surface layer, i.e. stresses, phase composition, structure. Machinability by abrasive tools depends on the machining performance affected both by the blank material properties and various processing factors. In our previous studies, we proved that during abrasive machining the metal microvolume affected by abrasive grains accumulates energy. This energy is used for metal dispersion and is converted into heat. According to the theoretical studies described herein, one may note the absence of a reliable and scientifically valid method as well as measuring instruments to determine the machinability of metals and alloys by abrasive tools. For this reason, we suggested a method simulating the effect the multiple abrasive grains produce in a grinding wheel, and enabling us to identify machinability of metals and alloys, select the most efficient abrasive materials for machining of the same, and form the basis for development of effective grinding operations.

Heterogeneous Structure in Blends of Rubber Polymers

1965 ◽  
Vol 38 (1) ◽  
pp. 62-75 ◽  
Author(s):  
M. H. Walters ◽  
D. N. Keyte
Keyword(s):  
Zinc Oxide ◽  
Electron Microscope ◽  
Physical Properties ◽  
Polymer Blends ◽  
Phase Contrast ◽  
Heterogeneous Structure ◽  
Phase Contrast Microscope ◽  
Mixed Solutions ◽  
Molecular Scale ◽  
Contrast Microscope

Abstract The phase contrast microscope has been used to examine blends of rubber polymers. Mixing on a molecular scale was never observed, the more homogeneous blends consisting of a pair of interlocking “networks” with a mesh diameter of about a micron. Blending was less perfect when the polymers were of widely different viscosities, and in the worst cases consisted of lumps of the stiffer polymer embedded in the softer polymer. Blends prepared by drying mixed solutions were always exceedingly heterogeneous. Physical properties of gum stocks were not greatly affected by the size of this heterogeneity, although there was evidence from electron microscope surface replicas that rupture surfaces tend to follow the interface between the polymers. The distribution of filler, zinc oxide and protein in blends was studied using a variety of techniques. It was found that these materials (and probably many other compounding ingredients) are not always evenly distributed between the polymers, and this may be expected to affect adversely the physical properties.

Grinding of Carbon/Epoxy Composites Using Electroplated CBN Wheel with Controlled Abrasive Clusters

2008 ◽  
Vol 389-390 ◽  
pp. 24-29 ◽  
Author(s):  
H.P. Yuan ◽  
Hang Gao ◽  
Yong Jie Bao ◽  
Yong Bo Wu
Keyword(s):  
Epoxy Composite ◽  
Epoxy Composites ◽  
Grinding Wheel ◽  
The Novel ◽  
Grinding Wheels ◽  
Grinding Forces ◽  
Abrasive Grains ◽  
Dry Grinding ◽  
Conventional Grinding ◽  
Wheel Loading

Aiming at solving the problems of wheel loading in dry grinding of Carbon/Epoxy composite materials, a novel electroplated grinding wheel with controlled abrasive cluster was developed, in which the diameter of clusters is in Φ0.2 mm to Φ1.0 mm and the interspace between them is about 0.5 mm to 1.0 mm. A conventional electroplated grinding wheel with abrasive grains distributed randomly was fabricated in the same way. The comparison experiments involving C/E composite were conducted on a vertical spindle grinder with the novel and conventional grinding wheels. The results show that the grinding forces of novel wheel developed is more lower though little larger surface roughness, and the wheel loading phenomenon is markedly decreased compared with conventional electroplated wheel.

Description of immature stages and adult diagnosis of Stilobezzia coquilletti Kieffer 1917 (Diptera: Ceratopogonidae)

Zootaxa ◽  
2008 ◽  
Vol 1958 (1) ◽  
pp. 31-40 ◽  
Author(s):  
MARÍA M. RONDEROS ◽  
CARLA G. CAZORLA ◽  
GUSTAVO R. SPINELLI ◽  
DAIANE SILVEIRA CARRASCO
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Phase Contrast ◽  
Immature Stages ◽  
Sandy Bottom ◽  
Phase Contrast Microscope ◽  
Contrast Microscope ◽  
Shallow Stream ◽  
Scanning Electron

The pupa and larva of Stilobezzia (Stilobezzia) coquilletti Kieffer are described, and a diagnosis of the adult is given. All described stages were photomicrographed and illustrated by using phase-contrast microscope, plus Scanning Electron Microscope in the case of the larva. Immature stages were collected in a shallow stream of sandy bottom nearby Manaus, Brazil. The pupa is compared with S. (S.) fiebrigi Kieffer, and the larva with S. (S.) antennalis Coquillett.

Characterization of High-Speed Alumina Abrasive Grinding Wheel

2020 ◽  
Vol 405 ◽  
pp. 365-369
Author(s):  
Zina Pavloušková ◽  
David Jech ◽  
Pavel Komarov ◽  
Ivana Ročňáková ◽  
Lucie Dyčková ◽  
...  
Keyword(s):  
High Speed ◽  
Raw Materials ◽  
Initial Mixture ◽  
Grit Size ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Abrasive Grains ◽  
Analysis Technique ◽  
High Speed Grinding

The high-speed grinding wheel can be defined as a self-sharpening composite structural tool composed from abrasive grains held in a specific binder. The main properties of grinding wheels depend on the type of abrasive elements, grit size, grade, binder and the resulting structure, which is influenced by several crucial technological processing steps. Preparation of an initial mixture of abrasive particles together with permanent binder’s mixture and temporary binder followed by pressing and high-temperature sintering is the essential technological step in the manufacturing of high-quality grinding wheels. High demands placed on functionality and quality together with constantly increasing effort to improve existing properties of grinding tools require detailed characterization of all input raw materials. For further research and development is crucial know, how each technological step can influence the final quality of the product. This contribution is focused on the characterization of four alumina abrasives with different grit size and two in chemical composition different binder mixtures which were used for the production of two different high-speed grinding wheels. Initial abrasive grains, binders and metallographic samples of high-speed grinding wheels were evaluated by means of scanning electron microscopy. The porosity of grinding wheels with different binding agents was also determined ustilizing digital image analysis technique.

Phase Contrast and Electron Microscope Studies of the Appearance and Behaviour of the White Cells of Normal Human Blood

1952 ◽  
Vol s3-93 (24) ◽  
pp. 395-412
Author(s):  
JUNE MARCHANT
Keyword(s):  
Electron Microscope ◽  
Cell Surface ◽  
Phase Contrast ◽  
Blood Platelets ◽  
Amoeboid Movement ◽  
Amoeboid Form ◽  
Contrast Microscope ◽  
Normal Human ◽  
Flat Membrane ◽  
Normal Human Blood

1. The phase-contrast microscope has been used to study form and movement of human leucocytes and blood platelets in three types of preparation; (a) warm sealed blood drops, (b) warm sealed films of leucocytes adhering to coverslips after incubation of blood drops at 37° C. for 30 minutes or more, and (c) warm sealed films of blood platelets obtained by similarly incubating drops of saline suspensions of these cells. Similar preparations to (b) and (c) were obtained on formvar films and studied in the electron microscope. Phagocytosis was studied in all the above preparations after adding suspensions of collodion particles or of Staphylococcus albus. 2. The neutrophils were the most versatile cells seen in the above preparations. The amoeboid forms were the most mobile and phagocytic. Another form showed rapidly waving processes which gradually spread into a flat membrane on the glass. lattened immobile neutrophils were still capable of phagocytosis. Bacteria which adhered to the cell surface moved over it towards the thicker central region of the cell where ingestion occurred. 3. Eosinophils showed a mobile amoeboid form and flattened forms which were often very bizarre in shape. They did not phagocytose readily. 4. Monocytes showed slowly moving amoeboid forms or forms with ruffle-like membranes around the cell. They were phagocytic. 5. Lymphocytes were capable of amoeboid movement but did not flatten on glass and were not phagocytic. 6. Blood platelets showed dendritic and flattened forms. Bacteria or collodion particles adhered to the surfaces of the latter and travelled over them, clustering at their thicker centres.

Effective thermal properties of grinding wheels and grains

1998 ◽  
Vol 212 (8) ◽  
pp. 661-669 ◽  
Author(s):  
M N Morgan ◽  
W B Rowe ◽  
S C E Black ◽  
D R Allanson
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Boron Nitride ◽  
Thermal Performance ◽  
Cubic Boron Nitride ◽  
Energy Partitioning ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Abrasive Grains ◽  
Effective Thermal Properties

The thermal properties of the grinding wheel are required for energy partitioning in grinding. This paper describes an investigation of the effective thermal properties of alumina and cubic boron nitride (CBN) grinding wheels. Results are presented for a novel sensor that was designed to measure the bulk thermal properties of grinding wheel samples. The effective bulk thermal properties of the grinding wheel and the effective thermal properties of the abrasive grains were also investigated. It was found that the bulk thermal property is dominated by the properties of the bond and does not account for the improved thermal performance of CBN compared with alumina. Values of the effective thermal conductivities for alumina and CBN abrasive grains are therefore proposed. It is concluded that the effective thermal conductivity of the grains is best obtained inversely from grinding experiments.

scholarly journals Description of the last instar larva and new contributions to the knowledge of the pupa of Dasyhelea mediomunda Minaya (Diptera, Culicomorpha, Ceratopogonidae)

2016 ◽  
Vol 88 (3 suppl) ◽  
pp. 1625-1633
Author(s):  
FLORENTINA DÍAZ ◽  
DANIELLE ANJOS-SANTOS ◽  
AMPARO FUNES ◽  
MARÍA M. RONDEROS
Keyword(s):  
Electron Microscope ◽  
Phase Contrast ◽  
Instar Larva ◽  
Fourth Instar ◽  
Fourth Instar Larva ◽  
Patagonian Steppe ◽  
Contrast Microscope ◽  
First Time ◽  
Small Wetland ◽  
Scanning Electron

ABSTRACT The fourth instar larva of Dasyhelea mediomunda Minaya is described for the first time and a complete description of the pupa is provided, through use of phase-contrast microscope and scanning electron microscope. Studied specimens were collected in a pond connected to a small wetland "mallin" on the Patagonian steppe, Chubut province, Argentina.

The method of assessment of the grinding wheel cutting ability in the plunge grinding

2012 ◽  
Vol 2 (3) ◽  
Author(s):  
Krzysztof Nadolny
Keyword(s):  
Working Conditions ◽  
Comparative Assessment ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Plunge Grinding ◽  
Abrasive Grains ◽  
Ceramic Bond ◽  
Method Of Assessment ◽  
Grinding Kinematics

AbstractThis article presents the method of comparative assessment of the grinding wheel cutting ability in the plunge grinding kinematics. A new method has been developed to facilitate multicriterial assessment of the working conditions of the abrasive grains and the bond bridges, as well as the wear mechanisms of the GWAS, which occur during the grinding process, with simultaneous limitation of the workshop tests range. The work hereby describes the methodology of assessment of the grinding wheel cutting ability in a short grinding test that lasts for 3 seconds, for example, with a specially shaped grinding wheel, in plunge grinding. The grinding wheel macrogeometry modification applied in the developed method consists in forming a cone or a few zones of various diameters on its surface in the dressing cut. It presents an exemplary application of two variants of the method in the internal cylindrical plunge grinding, in 100Cr6 steel. Grinding wheels with microcrystalline corundum grains and ceramic bond underwent assessment. Analysis of the registered machining results showed greater efficacy of the method of cutting using a grinding wheel with zones of various diameters. The method allows for comparative tests upon different grinding wheels, with various grinding parameters and different machined materials.

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