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Tianyu Yu - One of the best experts on this subject based on the ideXlab platform.
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grinding performance of textured monolayer cbn wheels undeformed Chip Thickness nonuniformity modeling and ground surface topography prediction
International Journal of Machine Tools & Manufacture, 2017Co-Authors: Tianyu YuAbstract:Abstract The ground surface roughness and topography are commonly used to characterize the surface finishing. In the application of textured monolayer CBN wheels, the nonuniformity of wheel topology will render a nonuniform undeformed Chip Thickness which greatly affects the ground surface. In order to predict the ground surface topography more accurately and efficiently, grinding experiment has been conducted in the current study, with measured grinding wheel topology. The measured surface topology of textured monolayer CBN wheels has been reconstructed by using the Johnson transformation and its inverse transformation. The influence of wheel topology evolution on the undeformed Chip Thickness nonuniformity has been determined with an improved model. It has been found the ground surface roughness is improved with a continuous reducing undeformed Chip Thickness nonuniformity. The percentage of active grains, the mean value and standard deviation of undeformed Chip Thickness have been found the main factors in determining the surface roughness. The reconstructed wheel surface topology has been used to predict the workpiece topography in different stages of the grinding process.
Jan-eric Ståhl - One of the best experts on this subject based on the ideXlab platform.
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True equivalent Chip Thickness for tools with a nose radius
2019Co-Authors: Jan-eric Ståhl, Mats Andersson, Carin AnderssonAbstract:A majority of the established systems for choice and optimization of cutting data are based on Woxen’s equivalent Chip Thickness, heW. In metal cutting theory and models, the equivalent Chip Thickness is of vital importance when the depth-of-cut ap is in the same order or smaller than the nose radius r. Woxen made considerable simplifications in his Chip area model, that form the basis for calculations of the equivalent Chip Thickness. Basic mathematical solutions, e.g. describing the Chip area on circular inserts, are lacking. This article describes the geometrical implications when machining with round inserts. The error in Woxen’s equivalent Chip Thickness is largest when the depth-of-cut is less than ¼ of the nose radius. The calculations of the equivalent Chip Thickness based on the Woxen model are up to 50 % wrong, for some combinations of cutting data in the finishing range. The presented results explain the difficulties in getting a good validity in the models used to calculate tool life in finishing machining. The error leads to an underrating of the tool load in many machining situations.
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Analysis of the minimum Chip Thickness during turning of duplex stainless steel
Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture, 2018Co-Authors: Fredrik Schultheiss, Volodymyr Bushlya, Mathias Agmell, Jan-eric StåhlAbstract:The goal of this study has been to establish a method for quantifying the minimum Chip Thickness, h1min, during longitudinal turning of duplex stainless steel, and explore how the value of h1min ch...
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Equivalent Chip Thickness and its Influence on Tool Life
Procedia Manufacturing, 2018Co-Authors: Daniel Johansson, Rebecka Lindvall, Malin Fröström, Volodymyr Bushlya, Jan-eric StåhlAbstract:This paper investigates the accuracy of using the Woxen equivalent Chip Thickness to represent feed, depth of cut, nose radius and major cutting angle in tool life modeling of machining low alloy steel in longitudinal turning. Hagglund’s way of calculating the equivalent Chip Thickness has been used and compared to the Woxen equation. The equivalent Chip Thickness was held constant as the tool life was recorded for varied feeds and depths of cut. The results show that the tool life decreases for an increase of depth of cut and a decrease of feed, using the same equivalent Chip Thickness.
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The Influence the Uncut Chip Thickness has on the Stagnation Point in Orthogonal Cutting
Procedia CIRP, 2017Co-Authors: Mathias Agmell, Daniel Johansson, Sampsa V.a. Laakso, Aylin Ahadi, Jan-eric StåhlAbstract:The effect of cutting data on the stagnation zone of a machining operation is of great interest since it governs the material flow around the cutting edge. The material flow has a significant influence on the mechanical properties of the machined surface. This paper presents a numerical model that is able to determine the effect that the uncut Chip Thickness has on the stagnation zone and the connection between the stagnation zone and the deformation layer in the machined subsurface.
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Analytical Calculation of the True Equivalent Chip Thickness for Cutting Tools and its Influence on the Calculated Tool Life
Advanced Materials Research, 2012Co-Authors: Jan-eric Ståhl, Fredrik SchultheissAbstract:A majority of the established systems for determination and optimization of cutting data are based on Woxen’s equivalent Chip Thickness, heW. In metal cutting theory and models, the equivalent Chip Thickness is of vital importance when the depth-of-cut ap is in the same order or smaller than the nose radius r. Woxen made considerable simplifications in his Chip area model, that form the basis for calculations of the equivalent Chip Thickness. Basic mathematical solutions, e.g. describing the Chip area on circular inserts, are lacking. This article describes the geometrical implications when machining with round inserts. The error in Woxen’s equivalent Chip Thickness is largest when the depth-of-cut is less than ¼ of the nose radius and are up to 40 % wrong for some combinations of cutting data in the finishing range. The presented results explain the difficulties in getting a good validity in the models used to calculate tool life in finishing machining. The error leads to an underrating of the tool load in many machining situations
Jun Wang - One of the best experts on this subject based on the ideXlab platform.
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Determination of the minimum Chip Thickness and the effect of the plowing depth on the residual stress field in micro-cutting of 18 Ni maraging steel
The International Journal of Advanced Manufacturing Technology, 2019Co-Authors: Yang Yao, Jun Wang, Hongtao Zhu, Chuanzhen Huang, Pu Zhang, Peng Yao, Xiaodan WangAbstract:Due to the cutting-edge radius effect in micro-cutting, there exists some material sticking in front of the cutting-edge named stagnation zone, above which the material flows as Chips. The location of the stagnation zone is reported to be associated with the minimum Chip Thickness in micro-cutting, which is a significant value influencing the cutting mechanics and the machined surface integrity in micro-cutting. The determination of the minimum Chip Thickness is of great importance in micro-cutting process. In this paper, the cutting force analysis on the shearing plane was carried out considering the ductile fracture and cutting-edge radius. Based on the cutting force analysis, this paper proposed a new method to determine the minimum Chip Thickness in micro-cutting of 18Ni maraging steel through finite element simulation. The minimum Chip Thickness was calculated to be 0.25 times the cutting-edge radius, which is in a good agreement with the velocity distribution analysis of the material around the cutting-edge. In addition, the effect of the plowing depth which was equivalent to the height of the stagnation zone on the residual stress filed was investigated using energy criterion. The energy stored in the machined surface increased with the plowing depth, resulting from the increasing thermal-mechanical load due to plowing.
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Maximum undeformed equivalent Chip Thickness for ductile-brittle transition of zirconia ceramics under different lubrication conditions
International Journal of Machine Tools and Manufacture, 2017Co-Authors: Min Yang, Chang He Li, Ya Li Hou, Runze Li, Yanbin Zhang, Dongzhou Jia, Xianpeng Zhang, Jun WangAbstract:This study investigates the critical maximum undeformed equivalent Chip Thickness for ductile-brittle transition (DBhmax-e) of zirconia ceramics under different lubrication conditions. A DBhmax-e model is developed through geometry and kinematics analyses of ductile-mode grinding. Result shows that DBhmax-e decreases with increasing friction coefficient (μ). An experimental investigation is then conducted to validate the model and determine the effect of dry lubrication, minimum quantity lubrication (MQL), and nanoparticle jet minimum quantity lubrication (NJMQL) conditions on DBhmax-e. According to different formation mechanisms of debris, the grinding behavior of zirconia ceramics is categorized into elastic sliding friction, plastic removal, powder removal, and brittle removal. Grinding forces per unit undeformed Chip Thickness (Fn/h and Ft/h) are obtained. The lubrication condition affects the normal force and ultimately influences the resultant force on workpiece. In comparison with dry grinding (DBhmax-e = 0.8 μm), MQL and NJMQL grinding processes increase DBhmax-e by 0.99 and 1.79 μm respectively; this finding is similar to model result. The theoretical model is then assessed by different volume fractions of nanofluids under NJMQL condition with an average percentage error of less than 8.6%.
Min Yang - One of the best experts on this subject based on the ideXlab platform.
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effect of friction coefficient on Chip Thickness models in ductile regime grinding of zirconia ceramics
The International Journal of Advanced Manufacturing Technology, 2019Co-Authors: Min Yang, Chang He Li, Yanbin Zhang, Runze LiAbstract:The removal of material in the ductile regime while improving machining efficiency is currently the technical bottleneck in grinding zirconia ceramics. Prediction models of minimum Chip Thickness (hmin) and ductile–brittle transition Chip Thickness (hd–b) were developed according to grinding mechanism. Results showed that both hmin and hd–b decreased with increasing friction coefficient. Grinding experiments were carried out using the maximum undeformed Chip Thickness as the input parameter. Experimental results showed that the hmin value in dry grinding is 0.24 μm. Meanwhile, the hmin values under minimum quantity lubrication (MQL) and nanoparticle jet MQL (0.4, 0.8, 1.2, 1.6, and 2 vol.%) are 0.27, 0.34, 0.49, 0.65, 0.76, and 0.91 μm, respectively. Furthermore, the hd–b value in dry grinding is 0.8 μm, and the hd–b values under lubrication condition that corresponds to hmin are 1.79, 1.98, 2.15, 2.27, 2.39, and 2.59 μm, respectively. The experimental results show the same trend as that of the prediction model. The theoretical calculation is basically consistent with the measured values, with model errors of 7.9% and 6.3%, thereby verifying the accuracy of the Chip Thickness models.
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Maximum undeformed equivalent Chip Thickness for ductile-brittle transition of zirconia ceramics under different lubrication conditions
International Journal of Machine Tools and Manufacture, 2017Co-Authors: Min Yang, Chang He Li, Ya Li Hou, Runze Li, Yanbin Zhang, Dongzhou Jia, Xianpeng Zhang, Jun WangAbstract:This study investigates the critical maximum undeformed equivalent Chip Thickness for ductile-brittle transition (DBhmax-e) of zirconia ceramics under different lubrication conditions. A DBhmax-e model is developed through geometry and kinematics analyses of ductile-mode grinding. Result shows that DBhmax-e decreases with increasing friction coefficient (μ). An experimental investigation is then conducted to validate the model and determine the effect of dry lubrication, minimum quantity lubrication (MQL), and nanoparticle jet minimum quantity lubrication (NJMQL) conditions on DBhmax-e. According to different formation mechanisms of debris, the grinding behavior of zirconia ceramics is categorized into elastic sliding friction, plastic removal, powder removal, and brittle removal. Grinding forces per unit undeformed Chip Thickness (Fn/h and Ft/h) are obtained. The lubrication condition affects the normal force and ultimately influences the resultant force on workpiece. In comparison with dry grinding (DBhmax-e = 0.8 μm), MQL and NJMQL grinding processes increase DBhmax-e by 0.99 and 1.79 μm respectively; this finding is similar to model result. The theoretical model is then assessed by different volume fractions of nanofluids under NJMQL condition with an average percentage error of less than 8.6%.
Sanjay Agarwal - One of the best experts on this subject based on the ideXlab platform.
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An Analytical Chip Thickness Model for Performance Assessment in Silicon Carbide Grinding
Procedia Manufacturing, 2017Co-Authors: Sanjay Agarwal, Sanchit Kr. Khare, Ved Prakash Pandey, Manoj PatelAbstract:Abstract The Chip-Thickness models, used to assess the performance of grinding processes, play important role in predicting the surface quality. In the present paper, an attempt has been made to develop a new Chip-Thickness model for the performance assessment of Silicon Carbide grinding by incorporating the real contact length in the existing basic Chip-Thickness model. The new model has been validated by conducting experiments, taking the surface roughness as a parameter of evaluation.
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predictive modeling of undeformed Chip Thickness in ceramic grinding
International Journal of Machine Tools & Manufacture, 2012Co-Authors: Sanjay AgarwalAbstract:Abstract The quality of the surface produced during ceramic grinding is important as it influences the performance of the finished part to great extent. The undeformed Chip Thickness is a variable often used to describe the quality of ground surfaces as well as to evaluate the competitiveness of the overall grinding system. Hence, the estimation of undeformed Chip Thickness can cater to the requirements of performance evaluation. But, the undeformed Chip Thickness is governed by many factors and its experimental determination is laborious and time consuming. So the establishment of a model for the reliable prediction of undeformed Chip Thickness is still a key issue for ceramic grinding. In this study, a new undeformed Chip-Thickness model is developed, for the reliable prediction of undeformed Chip Thickness in ceramic grinding, on the basis of stochastic nature of the grinding process, governed mainly by the random geometry and the random distribution of cutting edges. The model includes the real contact length that results from combined contact length, due to wheel–workpiece contact zone deflection and the local deflection due to the microscopic contact at the grain level and contact length due to geometry of depth of cut. The mechanical properties of workpiece material and the grinding parameters are also considered in the undeformed Chip Thickness model through normal grinding force model. The new model has been validated by the experimental results of silicon carbide grinding, taking the surface roughness as a parameter of evaluation.