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.

Analysis of Grinding Temperatures by Energy Partitioning

1996 ◽  
Vol 210 (6) ◽  
pp. 579-588 ◽  
Author(s):  
W B Rowe ◽  
S C E Black ◽  
B Mills ◽  
H S Qi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Cubic Boron Nitride ◽  
Thermal Characteristics ◽  
Theoretical Models ◽  
Relative Magnitude ◽  
Partition Ratio ◽  
Energy Partitioning ◽  
Grinding Wheel ◽  
Effective Thermal Properties

The partitioning of heat between two sliding bodies depends strongly on the relative magnitude of the thermal characteristics of each body. Grinding with the superabrasive CBN (cubic boron nitride) gives the favourable condition of a high thermal conductivity wheel, allowing increased heat to be carried away by the grinding wheel. This reduces the temperatures experienced by the workpiece. In this paper different methods of theoretical partitioning in grinding are reviewed. The partition ratio is the proportion of the total grinding energy that enters the workpiece. The partition ratio in surface grinding was measured using a thermocouple technique. Theoretical models for predicting the partition ratio were correlated with measured results to establish the effective thermal properties of CBN and aluminium oxide abrasives. The effective thermal conductivity of CBN was found to be considerably lower than the reported theoretical value. The findings provide the basis for improved prediction of workpiece temperatures in grinding.

Automation of calculations of cutting modes taking into account the wear of cubic boron nitride tools when applying solid lubricants

2021 ◽  
pp. 67-70
Author(s):  
Keyword(s):  
Boron Nitride ◽  
High Speed ◽  
Solid Lubricant ◽  
Cubic Boron Nitride ◽  
High Speed Steel ◽  
Solid Lubricants ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Ceramic Bond ◽  
Calculation System

The effect of a solid lubricant on the wear of cubic boron nitride grinding wheels on a ceramic bond of different hardness and grain size in the processing of high-speed steel is investigated. The dependences of the change in the wear of cubic boron nitride on the parameters of the processing mode are determined. An automated calculation system is proposed to control the consumption of cubic boron nitride grinding wheels in production conditions. Keywords: solid lubricant, grinding, high speed steel, cubic boron nitride grinding wheel, consumption, wear, grinding mode. [email protected]

Design of Flexible Grinding Wheel With Variable Hub Thickness

1994 ◽  
Vol 116 (2) ◽  
pp. 260-262 ◽  
Author(s):  
Z. M. Bzymek ◽  
G. Song ◽  
T. D. Howes ◽  
R. E. Garrett
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boron Nitride ◽  
Variable Thickness ◽  
Cubic Boron Nitride ◽  
Grinding Wheel ◽  
The Finite Element Method ◽  
Grinding Wheels ◽  
Major Step ◽  
Element Method

In this paper, various Cubic Boron Nitride (CBN) grinding wheels designed to suppress chatter are statically and dynamically analyzed and compared by means of the Finite Element Method (FEM). As a result of these analyses, a flexible wheel with a variable thickness hub is proposed. Theoretically, the new wheel should suppress chatter and thus be a major step forward in grinding wheel design.

Increasing the effectiveness of deep grinding of the locking element of a turbine blade with an "Aerobor® II" highly porous cubic boron nitride grinding wheel

2021 ◽  
pp. 68-71
Author(s):  
Keyword(s):  
Boron Nitride ◽  
Turbine Blade ◽  
Nickel Alloys ◽  
Cubic Boron Nitride ◽  
Turbine Blades ◽  
Grinding Wheel ◽  
High Porosity ◽  
Grinding Wheels ◽  
New Generation ◽  
Highly Porous

The results of testing new generation Aerobor® II cubic boron nitride grinding wheels during machining of the locking element of turbine blades are presented. The advantages of using new high-porosity cubic boron nitride grinding wheels in comparison with abrasive grinding wheels in deep grinding of parts made of heat-resistant nickel alloys are described. Keywords: deep grinding, turbine blade, locking element, high-temperature nickel alloys, high-porosity cubic boron nitride grinding wheel [email protected], [email protected], [email protected]

scholarly journals Modelling and Analysis of Topographic Surface Properties of Grinding Wheels

2021 ◽  
Vol 5 (4) ◽  
pp. 121
Author(s):  
Praveen Sridhar ◽  
Daniel Mannherz ◽  
Kristin M. de Payrebrune
Keyword(s):  
Surface Topography ◽  
Cubic Boron Nitride ◽  
Volume Ratio ◽  
Fabrication Process ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Hard Materials ◽  
Abrasive Grains ◽  
Model And Simulation ◽  
Topography Model

Grinding is one of the effective manufacturing processes with which to produce highly accurate parts with an ultra-fine surface finish. The tool used to remove materials in grinding is called the grinding wheel. Abrasive grains made of extremely hard materials (alumina, silica, cubic boron nitride, and diamond) having a definite grit size but a random shape are bonded on the circumferential surface of the grinding wheel. The fabrication process is controlled so that the wheel exhibits a prescribed structure (in the scale of soft to hard). At the same time, the distribution of grains must follow a prescribed grade (in the scale of dense to open). After the fabrication, the wheel is dressed to make sure of its material removal effectiveness, which itself depends on the surface topography. The topography is quantified by the distribution and density of active abrasive grains located on the circumferential surface, the grains’ protrusion heights, and their pore volume ratio. The prediction of the surface topography mentioned above requires a model that considers the entire manufacturing process and the influences on the grinding wheel properties. This study fills this gap in modelling the grinding wheel by presenting a surface topography model and simulation framework for the effect of the grinding wheel fabrication process on the surface topography. The simulation results have been verified by conducting experiments. This study will thus help grinding wheel manufacturers in developing more effective grinding wheels.

scholarly journals Thermal properties of polycrystalline cubic boron nitride sintered under high pressure condition

2018 ◽  
Vol 50 (4) ◽  
pp. 401-408
Author(s):  
Chunwei Leng ◽  
Xiaojun Hu ◽  
Hongliang Xie ◽  
Chunhua Shen
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Boron Nitride ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Bending Strength ◽  
Hexagonal Boron Nitride ◽  
Cubic Boron Nitride ◽  
Chemical Properties

The excellent thermal and chemical properties of cubic boron nitride (cBN) indicate that it is potential materials to prepare the thermal dissipate substrate applied in the electronic packaging. The thermal properties of polycrystalline cBN ceramics, however, have not been fully investigated. We report the first sintering experiment on preparing polycrystalline cBN ceramics using cBN powder as starting material without any sintering aids. The microstructure and high bending strength show that the strong combination was achieved among the crystal grains. The measured results, including density, thermal conductivity and thermal expansion coefficient, reveal that the properties of this ceramics depend on the grain size of starting crystal cBN. The PcBN ceramics has low thermal expansion coefficient extremely matching to that of silicon and exhibits moderate thermal conductivity due to its low density and the existence of low thermal conductive phase of hexagonal boron nitride.

A Self-Heated Thermistor Technique to Measure Effective Thermal Properties From the Tissue Surface

1987 ◽  
Vol 109 (4) ◽  
pp. 330-335 ◽  
Author(s):  
P. A. Patel ◽  
J. W. Valvano ◽  
J. A. Pearce ◽  
S. A. Prahl ◽  
C. R. Denham
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Tissue Blood Flow ◽  
Conductivity Measurements ◽  
Bioheat Equation ◽  
Tissue Conductivity ◽  
Diffusivity Measurements ◽  
Tissue Surface ◽  
Effective Thermal Properties

A microcomputer based instrument to measure effective thermal conductivity and diffusivity at the surface of a tissue has been developed. Self-heated spherical thermistors, partially embedded in an insulator, are used to simultaneously heat tissue and measure the resulting temperature rise. The temperature increase of the thermistor for a given applied power is a function of the combined thermal properties of the insulator, the thermistor, and the tissue. Once the probe is calibrated, the instrument accurately measures the thermal properties of tissue. Conductivity measurements are accurate to 2 percent and diffusivity measurements are accurate to 4 percent. A simplified bioheat equation is used which assumes the effective tissue thermal conductivity is a linear function of perfusion. Since tissue blood flow strongly affects heat transfer, the surface thermistor probe is quite sensitive to perfusion.

Potential for improving efficiency of the internal cylindrical grinding process by modification of the grinding wheel structure—Part II: Grinding wheels made of superabrasive grains

2016 ◽  
Vol 231 (4) ◽  
pp. 813-823 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Witold Habrat
Keyword(s):  
Cubic Boron Nitride ◽  
Positive Influence ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Structural Modifications ◽  
Synthetic Diamonds ◽  
Wide Range ◽  
Internal Cylindrical Grinding ◽  
Different Diameters

This article offers an overview of 11 grinding wheel construction modifications used in the peripheral grinding of flat, shaped, internal, and external cylindrical surfaces, when grinding wheels made of superabrasive grains are used (natural and synthetic diamonds, as well as mono- and microcrystalline cubic boron nitride). The text contains characteristics of grinding wheels with: bubble corundum grains, glass-crystalline bond, conic chamfer, zones of different diameters, a centrifugal provision of the coolant into the grinding zone, aggregate grains, zone-diversified structure, as well as impregnated (self-lubricating), multiporous, segment and “intelligent” grinding wheels. Each of the presented structural modifications were described by giving construction scheme, used abrasive grains, range of applications, advantages as well as disadvantages. Modifications of the grinding wheel construction allow for effective improvement of both the conditions and the results of the grinding process. A wide range of the known modifications allow for their proper selection depending on the required criteria of effective evaluation and taking into account the specific characteristics of superabrasive grains. As a result, it is possible to obtain positive influence on a number of technological factors of the grinding process. The described modifications of the grinding wheel structure can be also an inspiration and the basis for creating new solutions in this field.

Research of Grinding Material Tools by Modern Grinding Wheels

2013 ◽  
Vol 581 ◽  
pp. 211-216 ◽  
Author(s):  
Jiří Čop ◽  
Imrich Lukovics
Keyword(s):  
Boron Nitride ◽  
Surface Quality ◽  
High Surface ◽  
Cubic Boron Nitride ◽  
High Accuracy ◽  
Grinding Wheels ◽  
Cutting Depth ◽  
High Surface Quality ◽  
Materials Used

This research paper focuses on grinding of materials used for tools (100Cr6 (CSN 4 14109), X210Cr12 ( CSN 4 19436) and epoxy resin) using grinding wheels from cubic boron nitride and diamond. The disadvantage of grinding of difficult-to-machine materials is higher wear of grinding wheels. The modern grinding wheels are able to achieve high accuracy of dimensions and high surface quality with a smaller wear of grinding wheels then grinding wheels from conventional materials. Correctly selected technological conditions are one of the most important matters to achieve the required surface quality. The main aim of this research is to determine the influence of technological conditions to quality of surface after planar grinding. The research determines the influence of the grain type of grinding wheels, feed rate and cutting depth on the quality of functional surfaces.

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.

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