Influence of AA7075 crystallographic orientation on micro-grinding force

2018 ◽  
Vol 233 (8) ◽  
pp. 1831-1843 ◽  
Author(s):  
Man Zhao ◽  
Xia Ji ◽  
Steven Y Liang
Keyword(s):  
Flow Stress ◽  
Crystallographic Orientation ◽  
Factor Model ◽  
Grinding Force ◽  
Taylor Factor ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Force Model ◽  
Workpiece Material ◽  
Flow Stress Model

In micro-grinding, the depth of cut is smaller than the grain size of workpiece material. Since the micro-grinding wheel cuts through the grain boundaries, the crystallographic effects become more significant in the micro-grinding than that in macro-machining. To quantify the effect of crystallographic orientation on the flow stress of polycrystalline material, the Taylor factor model is developed by examining the number and type of the activated slip systems. Then, the shear force model is developed based on the flow stress model considering the effect of crystallographic orientation. Moreover, the plowing force is predicted based on the Vickers hardness of workpiece material and the plowing friction coefficient. A comprehensive model is then proposed to predict micro-grinding force by consolidating the mechanical, thermal, crystallographic, and size effect. Micro-grinding experiments adopting Taguchi’s method were conducted to verify the model, and the results indicated that the predictions agree well with the experimental data. Besides, single-factorial experiments were conducted with the only variable being Taylor factor and the results suggest that the Taylor factor model is capable of capturing the effect of crystallographic orientation on grinding force.

scholarly journals Forces prediction in micro-grinding single-crystal copper considering the crystallographic orientation

2018 ◽  
Vol 5 ◽  
pp. 15
Author(s):  
Man Zhao ◽  
Xia Ji ◽  
Beizhi Li ◽  
Steven Y. Liang
Keyword(s):  
Flow Stress ◽  
Single Crystal ◽  
Crystallographic Orientation ◽  
Factor Model ◽  
Taylor Factor ◽  
Force Model ◽  
Stress Model ◽  
Single Crystal Copper ◽  
Accuracy Of Prediction ◽  
Flow Stress Model

In the micro-grinding of single-crystal copper, the effect of crystallography becomes significant as the wheel works intra-crystalline. To quantify the effect of crystallographic orientation (CO) related to the cutting direction on the micro-grinding process, this article presents a Taylor factor model by examining the number and style of activated slip systems. Then, the flow stress model of monocrystalline material is developed considering the variation of the Taylor factor. Furthermore, the models of chip formation and rubbing forces are derived from the flow stress model, while the plowing force is predicted by the Vickers hardness. Then, the overall grinding force model of the whole wheel is developed by incorporating the process parameters and the wheel properties. Finally, micro-grinding experiments are conducted to verify the model, using only the Taylor factor as the variable. The proposed analysis is also compared with the previously reported model, which considers the Taylor factor as a constant of 3.06. The comparison between the two predictions and experimental data shows that the consideration of Taylor factor variability improves the accuracy of prediction.

Phase Transformation Prediction Considering Crystallographic Orientation in Microgrinding Multiphase Material

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Man Zhao ◽  
Xia Ji ◽  
Yixuan Feng ◽  
Steven Y. Liang
Keyword(s):  
Phase Transformation ◽  
Crystallographic Orientation ◽  
Factor Model ◽  
Taylor Factor ◽  
Depth Of Cut ◽  
Kinetics Parameters ◽  
Order Of Magnitude ◽  
Solid State Phase Transformation ◽  
Temperature Rate ◽  
Previous Prediction

Abstract This investigation proposes a physics-based model to predict the solid-state phase transformation of maraging steel subjected to microgrinding. In microgrinding, the effect of crystallography is significant on the grinding phase transformation in light of the fact that the depth of cut is on the same order of magnitude as the grain size. This paper proposes a predictive model of phase transformation considering crystallographic orientation (CO) with respect to the grinding direction based on the Taylor factor model. In addition, the flow stress model is modified by adding a CO sensitive term and incorporating the mechanical-thermal loadings. Furthermore, the temperature, temperature rate, strain rate, and Taylor factor are also combined in the model of phase transition. The kinetics parameters of the models are obtained by a regression analysis against experimental data. Finally, the modified models are validated with experiments data and compared with the previous prediction.

Mathematical Model of the Grinding Force With Account for Blunting of Abrasive Grains of the Grinding Wheel

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Dmitrii V. Ardashev ◽  
Aleksandr A. Dyakonov
Keyword(s):  
Forecast Model ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Force Model ◽  
Cyclic Loads ◽  
Workpiece Material ◽  
Stochastic Nature ◽  
Abrasive Grains ◽  
Working Surface ◽  
Abrasive Grain

The paper offers a simulation model of the grinding force with account for the current condition of the grinding wheel's working surface—the value of the abrasive grain blunting area. The model of blunting area takes into account various wear mechanisms for abrasive grains: the mechanical wear is realized on the provisions of the kinetic theory of the strength of a solid subjected to cyclic loads, and the physicochemical wear is based on the intensity of interaction between the abrasive and the treated material at grinding temperatures. The offered model of the grinding force takes into account the unsteady stochastic nature of the interaction between abrasive grains of the grinding wheel and the working surface and the intensity of workpiece material deformation resistance. The model is multifactorial and complex and can be realized by supercomputer modeling. The numerical implementation of the model was performed with application of supercomputer devices engaging parallel calculations. The performed experiments on measurement of the grinding force during circular grinding have shown a 10% convergence with the calculated values. The developed grinding force model can be used as a forecast model to determine the operational functionality of grinding wheel when used in varying technological conditions.

Effect of crystallographic orientation on the hardness of polycrystalline materials AA7075

2018 ◽  
Vol 233 (9) ◽  
pp. 3182-3192
Author(s):  
Man Zhao ◽  
Xia Ji ◽  
Beizhi Li ◽  
Steven Y Liang
Keyword(s):  
Experimental Data ◽  
Flow Stress ◽  
Vickers Hardness ◽  
Crystallographic Orientation ◽  
Factor Model ◽  
Taylor Factor ◽  
Polycrystalline Materials ◽  
Compression Tests ◽  
Micro Hardness ◽  
Model Compression

As one of the most important properties of materials, micro-hardness is influenced by material microstructure significantly. The reported data show that the micro-hardness of materials varies with the variation of crystallographic orientation. This paper presents an analytical model to quantify the effect of crystallographic orientation on micro-hardness by analyzing the mechanical behavior in the test of Vickers hardness. The plastic deformation occurs under the micro-indentation with the flow stress affected significantly by crystallographic orientation of material. This paper develops a Taylor factor model to quantify the effect of crystallographic orientation on the flow stress of polycrystalline materials, by examining the number and the style of activated slip systems. Considering the linear relationship between the flow stress and Vickers hardness, the effect of crystallographic orientation on the Vickers hardness is established. To verify the Taylor factor model, compression tests and Vickers hardness tests were conducted. The result shows that the predictions coincided with the experimental data, which suggests that the model considering the variation of crystallographic orientation is accurate and the Taylor factor model is reasonable. To analyze the sensitivity of flow stress and Vickers hardness to CO, this paper also predicted flow stress and hardness using models without considering the variability of Taylor factor and the athernal stress. The three predictions were compared with the experimental data, and the results proved that the model considering the variability Taylor factor improves flow stress and accuracy of hardness models.

Online force control of large optical grinding machine for brittle materials assisted by force prediction

2019 ◽  
Vol 234 (1-2) ◽  
pp. 14-26
Author(s):  
Shuo Lin ◽  
QianRen Wang ◽  
ZhenHua Jiang ◽  
YueHong Yin
Keyword(s):  
Cutting Parameters ◽  
Grinding Force ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Force Model ◽  
Orthogonal Experiments ◽  
Grinding Conditions ◽  
Carbide Ceramics ◽  
Grinding Machine ◽  
Silicon Carbide Ceramics

Trajectory planning of aspherical surfaces with appropriate cutting parameters is always a tedious task, especially on difficult-to-grind materials. Orthogonal experiments are usually designed and conducted first to get a full estimation of forces under different sets of grinding conditions (e.g. depth of cut and feeding velocity). However, all these data will change, as the grinding wheel becomes blunt. To reduce the work on the selection of grinding parameters and keep the grinding process stable, a new force-controlled grinding strategy for large optical grinding machine on brittle material is proposed. The grinding force is controlled by adjusting feeding velocity along the trajectories in real time. The grinding force model is established by analyzing the complex contact area between the arc-shaped wheel and the workpiece. The co-existing of brittle and ductile removal is also considered. For the longtime delay of the system, the controller foresees the grinding force in 0.4 s later based on the model proposed, to prevent the large overshoot of the force (up to 87.5%). The verification of the controller was conducted on silicon carbide ceramics. The force overshoot was reduced to 22.5%, and the motion accuracy was guaranteed by position servo within 5 µm. The subsurface damage along the trajectory was further analyzed and discussed.

scholarly journals Micro-grinding temperature prediction considering the effects of crystallographic orientation

2019 ◽  
Vol 6 ◽  
pp. 22
Author(s):  
Man Zhao ◽  
Xia Ji ◽  
Steven Y. Liang
Keyword(s):  
Crystallographic Orientation ◽  
Thermal Loading ◽  
Factor Model ◽  
Orientation Distribution ◽  
Taylor Factor ◽  
Energy Partition ◽  
Grinding Forces ◽  
Material Microstructure ◽  
Temperature Prediction ◽  
Experimental Values

Tensile stress and thermal damage resulting from thermal loading will reduce the anti-fraying and anti-fatigue of workpieces, which is undesirable for micro-grinding, so it is imperative to control the rise of temperature. This investigation aims to propose a physical-based model to predict the temperature with the process parameters, wheel properties and material microstructure taken into account. In the calculation of heat generated in the micro-grinding zone, the triangular heat-flux distribution is adopted. The reported energy partition model is also utilized to calculate the heat converted into the workpiece. In addition, the Taylor factor model is used to estimate the effects of crystallographic orientation (CO) and its orientation distribution function (ODF) on the workpiece temperature by affecting the flow stress and grinding forces in micro-grinding. Finally, the physical model is verified by performing micro-grinding experiments using the orthogonal method. The result proves that the prediction matches well with the experimental values. Besides, the single-factorial experiments are conducted with the result showing that the model with the consideration of the variation of Taylor factor improves the accuracy of the temperature prediction.

The Process Experimental Study on High Efficiency Deep Grinding for 9SiCr Alloy Steel with a CBN Wheel

2013 ◽  
Vol 457-458 ◽  
pp. 172-176
Author(s):  
Zong Fu Guo ◽  
Xiao Min Sheng ◽  
Gui Zhi Xie ◽  
De Zhen Yin ◽  
Wen Xin Li
Keyword(s):  
Surface Quality ◽  
Alloy Steel ◽  
High Efficiency ◽  
Removal Rate ◽  
Grinding Force ◽  
Wheel Speed ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Good Surface ◽  
High Removal Rate

This paper via investigate the process of 9SiCr alloy steel in high efficiency deep grinding to find the rule between grinding wheel speed vs depth of cut ap and speed of table vw with the grinding force and the surface quality. Intend to develop a suitable method of the grinding process of 9SiCr alloy steel in high efficiency deep grinding, to obtain high removal rate and good surface quality.

Force Modeling in Laser-Assisted Microgrooving Including the Effect of Machine Deflection

2009 ◽  
Vol 131 (1) ◽  
Author(s):  
Ramesh Singh ◽  
Shreyes N. Melkote
Keyword(s):  
Flow Stress ◽  
Cutting Force ◽  
Cutting Forces ◽  
Laser Power ◽  
Continuous Wave ◽  
Dimensional Accuracy ◽  
Thermal Softening ◽  
Depth Of Cut ◽  
Force Model ◽  
Cutting Force Model

Laser assisted mechanical micromachining is a process that utilizes highly localized thermal softening of the material by continuous wave laser irradiation applied simultaneously and directly in front of a miniature cutting tool in order to produce micron scale three-dimensional features in difficult-to-machine materials. The hybrid process is characterized by lower cutting forces and deflections, fewer tool failures, and potentially higher material removal rates. The desktop-sized machine used to implement this process has a finite stiffness and deflects under the influence of the cutting forces. The deflections can be of the same order of magnitude as the depth of cut in some cases, thereby having a negative effect on the dimensional accuracy of the micromachined feature. As a result, selection of the laser and cutting parameters that yield the desired reduction in cutting forces and deflection, and consequently an improvement in dimensional accuracy, requires a reliable cutting force model. This paper describes a cutting force model for the laser-assisted microgrooving process. The model accounts for the effect of elastic deflection of the machine X-Y stages on the forces and accuracy of the micromachined feature. The model combines an existing slip-line field based force model with a finite element based thermal model of laser heating and a constitutive material flow stress model to account for thermal softening. Experiments are carried out on H-13 steel (42 HRC (hardness measured on the Rockwell ‘C’ scale)) to validate the force model. The effects of process parameters, such as laser power and cutting speed, on the forces are also analyzed. The model captures the effect of thermal softening and indicates a 66% reduction in the shear flow stress at 35 W laser power. The cutting force and depth of cut prediction errors are less than 20% and 10%, respectively, for most of the cases examined.

scholarly journals An Improved Cutting Force Model for Ultrasonically Assisted Grinding of Hard and Brittle Materials

2021 ◽  
Vol 11 (9) ◽  
pp. 3888
Author(s):  
Renke Kang ◽  
Jinting Liu ◽  
Zhigang Dong ◽  
Feifei Zheng ◽  
Yan Bao ◽  
...  
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
Experimental Studies ◽  
Brittle Materials ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Force Model ◽  
Cutting Force Model ◽  
Fillet Radius ◽  
Hard And Brittle Materials

Cutting force is one of the most important factors in the ultrasonically assisted grinding (UAG) of hard and brittle materials. Many theoretical and experimental studies show that UAG can effectively reduce cutting forces. The existing models for UAG mostly assume an ideal grinding wheel with abrasives in both the end and lateral faces to accomplish material removal, whereas the important role of the transition fillet surface is ignored. In this study, a theoretical cutting force model is presented to predict cutting forces with the consideration of the diamond abrasives in the end face, the lateral face, and the transition fillet surface of the grinding tool. This study analyzed and calculated the vibration amplitudes and the cutting forces in both the normal and tangential directions. It discusses the influences of the input parameters (rotation speed, feed rate, amplitude, depth and radius of transition fillet) on cutting forces. The study demonstrates that the fillet radius is an important factor affecting the grinding force. With an increase in fillet radius from 0.2 to 1.2 mm, the grinding force increases by 139.6% in the axial direction and decreases by 70% in the feed direction. The error of the proposed cutting force model is 10.3%, and the experimental results verify the correctness of the force model.

scholarly journals Study of the Influence of Cutting Regime Parameters on Grinding Forces in Processing Tungsten Carbide Dk460uf

2014 ◽  
Vol 65 (1) ◽  
pp. 87-92
Author(s):  
Silvia Vulc
Keyword(s):  
Tungsten Carbide ◽  
Cutting Forces ◽  
Normal Component ◽  
Grinding Force ◽  
Tangential Component ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Test Results ◽  
Tungsten Carbides ◽  
Grinding Forces

Abstract This paper presents a study on grinding tungsten carbide DK460UF, through experimental investigation using diamond grinding wheel with 54 μm grain size. Different sets of experiments were performed to study the effects of the independent grinding parameters such as grinding wheel speed, feed and depth of cut on cutting forces. Test results showed that the feed and depth of cut influence significantly the cutting forces. The research was lead to optimize the process parameters for reducing cutting forces. In this way, for different parameters of cutting regime, it were measured the values of the components of the grinding force, tangential component, Ft and normal component Fn. The results of the experiment showed that it is better to use great speeds and small feed rate and depth of cut in grinding tungsten carbides, such as DK460UF

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