Research on the Grinding Force of the Basin-Like Grinding Wheel in Grinding Elliptical Grooves of Outer Race

2013 ◽  
Vol 823 ◽  
pp. 143-148
Author(s):  
Xiao Xue Li ◽  
Jun Ming Wang ◽  
Yu Qin Sun ◽  
Zhen Gang Gao
Keyword(s):  
High Speed ◽  
Grinding Force ◽  
The Other ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Feed Velocity ◽  
Outer Race ◽  
Abrasive Grains ◽  
Other Hand

In order to calculate the grinding force of the basin-like grinding wheel in grinding outer race elliptical grooves, the thesis simplifies the grinding process as follow: the evenly distributed abrasive grains move around grinding wheel axis along an imaginary ellipse at high speed, while the imaginary ellipse moves along the trace deflected from the grinding wheel axis simultaneously. The analysis of grinding force in CVJ outer race elliptical groove grinding with basin-like grinding wheel reveals that, the grinding force will be decreased, if wheel velocity increased and feed velocity decreased. On the other hand, with the decrease of inter-grain spacing, the grinding force of basin-like grinding wheel will be increased, but the grinding force of abrasive grit will be decreased.

scholarly journals Mathematical modeling of the surface roughness of the grinding wheel during straightening

2021 ◽  
pp. 53-59
Author(s):  
R. M. Strelchuk ◽  
S. M. Trokhimchuk
Keyword(s):  
Mathematical Modeling ◽  
Surface Roughness ◽  
High Speed ◽  
Roughness Parameter ◽  
Ground Surface ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Research Results ◽  
Abrasive Grains ◽  
Working Surface

Purpose. Research on the mechanism of influence of the straightening conditions of the grinding wheel, including the relative oscillations of the wheel and a multipoint diamond dresser, on the roughness of the ground surface and other machining results. Methodology. Straightening a grinding wheel with a multipoint diamond dresser is a process of high-speed destruction of a hard, abrasive material and its bond under the instantaneous forces, abrasive grains with a hard surface of a diamond crystal. During the grinding wheel straightening, the total component of normal forces causes correspondingly less elastic deformations in the wheel straightening tool system, which increases the accuracy of the geometric shape of the grinding wheel working surface. Findings. The research results make it possible to determine the parameters of the surface roughness of a workpiece and to find ways to control it to increase the efficiency of the grinding process. Originality. The regularities of the influence of the grinding wheel straightening conditions on the state of its working surface have been established. The paper shows that the initial arrangement of grains along the normal to the surface of the wheel is determined by its characteristics. When the abrasive grains hit the surface of the straightening tool, some of the vertices are chipped off, as a result of which the density of the grain vertices on the outer surface of the wheel increases. The straightening process was further developed in the direction of the non-uniform character of the location of the vertices of abrasive grains. The distribution of the grain position at the wheel bond depends on the straightening conditions. Since the removal of the allowance in the process of grinding is carried out by the most protruding grain vertices, then, consequently, the result of grinding will depend on their location and the conditions for the wheel straightening. Practical value. Application of the research results obtained in the work, namely, mathematical modeling of the surface roughness of the grinding wheel during straightening, makes it possible to calculate the roughness parameter of the ground surface. The work also shows that the level of chipping of the grain vertices depends on the grinding wheel straightening conditions, in particular, on the value of the axial feed of the straightening tool. In this case, lower stresses arise in the grains and the bond, and the tool works as a harder one. Straightening conditions affect the stability of the grinding wheel and its self-sharpening process in the machining zone. This determines the significant role of straightening in the results of the grinding process.

Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

2009 ◽  
Vol 407-408 ◽  
pp. 577-581
Author(s):  
Shi Chao Xiu ◽  
Zhi Jie Geng ◽  
Guang Qi Cai
Keyword(s):  
Surface Integrity ◽  
Contact Area ◽  
High Speed ◽  
Ground Surface ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Edge Contact ◽  
Cylindrical Grinding ◽  
Theoretic Foundations

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.

scholarly journals Study on the Effect of Grinding Pressure on Material Removal Behavior Performed on a Self-Designed Passive Grinding Simulator

2021 ◽  
Vol 11 (9) ◽  
pp. 4128
Author(s):  
Peng-Zhan Liu ◽  
Wen-Jun Zou ◽  
Jin Peng ◽  
Xu-Dong Song ◽  
Fu-Ren Xiao
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Service Life ◽  
Material Removal ◽  
Removal Rate ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Temperature ◽  
Grinding Efficiency

Passive grinding is a new rail grinding strategy. In this work, the influence of grinding pressure on the removal behaviors of rail material in passive grinding was investigated by using a self-designed passive grinding simulator. Meanwhile, the surface morphology of the rail and grinding wheel were observed, and the grinding force and temperature were measured during the experiment. Results show that the increase of grinding pressure leads to the rise of rail removal rate, i.e., grinding efficiency, surface roughness, residual stress, grinding force and grinding temperature. Inversely, the enhancement of grinding pressure and grinding force will reduce the grinding ratio, which indicates that service life of grinding wheel decreases. The debris presents dissimilar morphology under different grinding pressure, which reflects the distinction in grinding process. Therefore, for rail passive grinding, the appropriate grinding pressure should be selected to balance the grinding quality and the use of grinding wheel.

Aeroelastic Problems in connection with High-Speed Flight

1956 ◽  
Vol 60 (547) ◽  
pp. 459-475 ◽  
Author(s):  
E. G. Broadbent
Keyword(s):  
Mach Number ◽  
High Speed ◽  
The Other ◽  
Control Surface ◽  
The Past ◽  
Other Hand ◽  
Aerodynamic Derivatives ◽  
Mach Numbers ◽  
The One

SummaryA review is given of developments in the field of aeroelasticity during the past ten years. The effect of steadily increasing Mach number has been two-fold: on the one hand the aerodynamic derivatives have changed, and in some cases brought new problems, and on the other hand the design for higher Mach numbers has led to thinner aerofoils and more slender fuselages for which the required stiffness is more difficult to provide. Both these aspects are discussed, and various methods of attack on the problems are considered. The relative merits of stiffness, damping and massbalance for the prevention of control surface flutter are discussed. A brief mention is made of the recent problems of damage from jet efflux and of the possible aeroelastic effects of kinetic heating.

Study on Effect of Grinding Fluid Supply Parameters on Surface Integrity in Quick-Point Grinding for Green Manufacturing

2008 ◽  
Vol 53-54 ◽  
pp. 209-214 ◽  
Author(s):  
Shi Chao Xiu ◽  
Ya Dong Gong ◽  
Guang Qi Cai
Keyword(s):  
Surface Integrity ◽  
High Speed ◽  
Point Contact ◽  
Green Manufacturing ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Fluid ◽  
Fluid Supply ◽  
High Speed Grinding ◽  
Grinding Power

In high and super-high speed grinding process, there is an airflow layer with high speed around the circle edge of the grinding wheel that hinders the grinding fluid into contact layer, namely, the air barrier effect. The speed of airflow layer is directly proportional to the square of the wheel speed. Quick-point grinding is a new type of high and super-high speed grinding process with a point contact zone and less grinding power. The edge effect of the air barrier is weakened because the thin CBN wheel is applied in the process. By the analysis of dynamic pressure and velocity distributions in the airflow layer around the wheel edge, the mathematic models of the flow and jet pressure of grinding fluid for effective supply in the process were established and the process of optimization calculation of the jet nozzle diameter for green manufacturing was also analyzed based on the thermodynamics and the technical character of quick-point grinding process. The quick-point grinding experiment for surface integrity influenced by grinding fluid supply parameters was performed.

Development of Three-Dimensional Dynamometer for Wafer Grinder

2010 ◽  
Vol 126-128 ◽  
pp. 361-366 ◽  
Author(s):  
Xiang Long Zhu ◽  
Ren Ke Kang ◽  
Yong Qing Wang ◽  
Dong Ming Guo
Keyword(s):  
Three Dimensional ◽  
High Sensitivity ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Performance Parameters ◽  
Grinding Forces ◽  
Grinding Method ◽  
Static Performance ◽  
Good Repeatability

Grinding forces during grinding silicon wafer have great influences on the accuracy, surface quality and grinding yield of the wafer. It is necessary to develop an accurate and reliable grinding dynamometer for measuring and monitoring the grinding process of the large and thin wafer. In this work, a new 3D (three-dimensional) grinding dynamometer using piezoelectric sensors is designed and developed, which is used for a wafer grinder based on wafer rotating grinding method. The calibrating experiments of the 3D grinding dynamometer are carried out. The FEA and modal analysis are made and compared with the results of mode testing. Furthermore, the static performance parameters of the dynamometer are obtained from the loading experiment. The experiment results indicate that the 3D grinding dynamometer can measure axial, radial and tangential grinding force of grinding wheel with high sensitivity, good linearity, good repeatability and high natural frequency, and fully satisfied requirement for measuring and monitoring of the grinding force in wafer grinding process.

scholarly journals FPGA-Based Synthesis of High-Speed Hybrid Carry Select Adders

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
V. Kokilavani ◽  
K. Preethi ◽  
P. Balasubramanian
Keyword(s):  
High Speed ◽  
Boolean Logic ◽  
The Other ◽  
Square Root ◽  
Verilog Hdl ◽  
Other Hand ◽  
Carry Select Adder

Carry select adder is a square-root time high-speed adder. In this paper, FPGA-based synthesis of conventional and hybrid carry select adders are described with a focus on high speed. Conventionally, carry select adders are realized using the following: (i) full adders and 2 : 1 multiplexers, (ii) full adders, binary to excess 1 code converters, and 2 : 1 multiplexers, and (iii) sharing of common Boolean logic. On the other hand, hybrid carry select adders involve a combination of carry select and carry lookahead adders with/without the use of binary to excess 1 code converters. In this work, two new hybrid carry select adders are proposed involving the carry select and section-carry based carry lookahead subadders with/without binary to excess 1 converters. Seven different carry select adders were implemented in Verilog HDL and their performances were analyzed under two scenarios, dual-operand addition and multioperand addition, where individual operands are of sizes 32 and 64-bits. In the case of dual-operand additions, the hybrid carry select adder comprising the proposed carry select and section-carry based carry lookahead configurations is the fastest. With respect to multioperand additions, the hybrid carry select adder containing the carry select and conventional carry lookahead or section-carry based carry lookahead structures produce similar optimized performance.

The Adaptive Control of Grinding Force of CNC Cam Grinder Based on Neural Network

2012 ◽  
Vol 217-219 ◽  
pp. 2051-2055
Author(s):  
Ming Li Xie ◽  
Ling Lu
Keyword(s):  
Neural Network ◽  
Adaptive Control ◽  
Control Method ◽  
Metal Removal ◽  
Removal Rate ◽  
Grinding Force ◽  
Control Measures ◽  
Numerical Control ◽  
Grinding Wheel ◽  
Grinding Process

In the process of cam grinding, the fluctuation of grinding force can lead to the abnormal wear of the grinding wheel, the decrease of the grinding surface quality and even the damage of the grinding process system. The paper took the grinding process of numerical control cam grinding machine as research subject, the grinding force mathematical model was built, the indirect test and control measures were researched and an adaptive control method based on neural network was proposed and applied to the grinding force control of the cam grinding process. At last, the controller was designed and the grinding simulation was performed with MATLAB, which proved that the system could solve the fluctuation of grinding force during the process of cam grinding and the controller was equipped with good dynamic characteristic. The results indicate that the method can realize the purpose of optimal metal removal rate and enhance the grinding quality of cams.

GMS Economic Corridors Under the Belt and Road Initiative

2019 ◽  
Vol 1 (2) ◽  
pp. 183-206
Author(s):  
Masami Ishida
Keyword(s):  
High Speed ◽  
Yunnan Province ◽  
Lao Pdr ◽  
The Other ◽  
Transport Infrastructure ◽  
Belt And Road Initiative ◽  
Other Hand ◽  
Belt And Road ◽  
The Government ◽  
The Belt And Road

The government of China promotes the development of expressways and high-speed expressways in Greater Mekong Subregion (GMS) and tries to connect the major cities of the subregion and Kunming under the Belt and Road Initiative (BRI). First, this article reviews the development schemes in the subregion including GMS economic cooperation and the BRI. Next, it introduces the development of the transport infrastructure, including expressways and high-speed railways, connecting Kunming and Lao People’s Democratic Republic (Lao PDR), Thailand, Myanmar and Vietnam. Thereafter, it compares the total costs of the projects and how other GMS countries negotiate with China. Seeing the sections of the expressways and railways in Yunnan Province, the shares of some sections occupied by bridges and tunnels are higher than 20 per cent due to the mountainous land feature of Yunnan Province. On the other hand, the railway in Lao PDR passes through the mountainous areas, and they adopted higher specification as same as in Yunnan Province. Consequently, the debt-default risk of Lao PDR has increased. On the other hand, Thailand repeated tough negotiations with China and made efforts not to increase the total cost. The negotiations of Lao PDR and Thailand with China are illustrated in this article. JEL Codes: O18, R10, R41, R58

Quantitative E-beam Probe for Valid High-Speed Measurements

1999 ◽  
Author(s):  
C. T. Salling
Keyword(s):  
Measurement Error ◽  
Transient Response ◽  
High Speed ◽  
Sampling Time ◽  
The Other ◽  
Other Hand ◽  
Timing Measurement ◽  
Time Accuracy ◽  
Accuracy And Repeatability ◽  
Measurement Capabilities

Abstract This paper presents the results of a study to assess the timing measurement capabilities of e-beam probes and how they compare to mechanical probes in terms of sampling time, accuracy, and repeatability. Analysis of the data indicates that the transient response of mechanical probes is prone to overshoot and ringing, which contributes significantly to measurement error and uncertainty. E-beam probes, on the other hand, are subject to charging effects and interference which, as the authors show, can be effectively eliminated, facilitating high-speed timing measurements accurate to within a few picoseconds.

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