Samy Oraby | Pharos University In Alexandria (original) (raw)

Papers by Samy Oraby

DOAJ: Directory of Open Access Journals - DOAJ, 2022

Hardness of the widely used structural steel is of vital importance since it may help in the dete... more Hardness of the widely used structural steel is of vital importance since it may help in the determination of many mechanical properties of a material under loading situations. In order to obtain reliable information for design, properties homogeneity should be validated. In the current study the hardness variation over the different diameters of the same AISI 4140 bar is investigated. Measurements were taken on the two faces of the stock at equally spaced eight sectors and fifteen layers. Statistical and graphical analysis are performed to asses the distribution of hardness measurements over the specified area. Hardness measurements showed some degree of dispersion with about ± 10% of its nominal value provided by manufacturer. Hardness value is found to have a slight decrease trend as the diameter is reduced. However, an opposite behavior is noticed regarding the sequence of the sector indicating a nonuniform distribution over the same area either on the same face or considering t...

Applied Mechanics and Materials, 2014

The impact of the cutting parameters; speed, feed, and depth of cut on the wear and the life of t... more The impact of the cutting parameters; speed, feed, and depth of cut on the wear and the life of the cutting edge has long been a matter of debate among researchers. The cutting speed has long been agreed to have a prime influence in such a way that increasing speed leads to higher wear rate. Depth of cut has been concluded by majority of studies to have insignificant or negligible impact on edge wear and deformation. Despite its long established influence on the roughness of the machined surface, the effect of cutting feed on edge wear and deformation still requires more explanation. Cutting feed is a crucial parameter governing the product surface finish and dimensional accuracy and, therefore, its attitude during machining should be fully understood. This study presents experimental and modeling approach to detect the feed-wear functional interrelation considering various domains of the cutting speed. Results showed that the impact of the cutting feed is firmly associated with the...

Applied Mechanics and Materials, 2013

The determination of actual stresses over the tool-workpiece interface has long been a matter of ... more The determination of actual stresses over the tool-workpiece interface has long been a matter of debate among researchers. Evaluation of the nature and the geometry of the wear contact area were always associated with many, sometime impractical, assumptions. The indeterministic fashion of edge wear and deformation requires a more realistic way to predict the actual wear contact area. In the current study, many wear area patterns are proposed considering the different wear modes of the cutting edge. The selection of the most correlated pattern to a specific edge deformation is justified using the relevant variations in the radial and the axial force components. For a regular wear over the entire cutting edge, a wear pattern that considers nose and/or flank is justified. When the cutting edge plastically fails, a pattern that considers only nose wear is preferred. As the cutting edge is subjected to many types of irregular disturbances of edge fracture and chipping, a wear pattern con...

In conventional numerical control machining, it is not possible to change the preset operating pa... more In conventional numerical control machining, it is not possible to change the preset operating parameters in the program during the machining cycle. By contrast, the adaptive control technique uses real-time sensing to continuously and instantaneously adjust the operative feed and/or the speed parameters to their optimal levels in order to ensure a more productive operation. In this study, a model-based adaptive control simulation strategy is proposed to optimize metal removal during rough turning by efficiently utilizing the available power resources within a safe machining environment. The approach is based on recursive continuous iterations to predict the instantaneous level of edge wear, together with the corresponding cutting forces and the consumed power, by considering the relevant models. The best speed-feed pair that provides the maximum metal removal rate without violating the imposed forces and power constraints is selected. Procedures are repeated for subsequent cut inte...

Coated tool inserts can be considered as the backbone of machining processes due to their wear an... more Coated tool inserts can be considered as the backbone of machining processes due to their wear and heat resistance. However, defects of coating can degrade the integrity of these inserts and the number of these defects should be minimized or eliminated if possible. Recently, the advancement of coating processes and analytical tools open a new era for optimizing the coating tools. First, an overview is given regarding coating technology for cutting tool inserts. Testing techniques for coating layers properties, as well as the various coating defects and their assessment are also surveyed. Second, it is introduced an experimental approach to examine the possible coating defects and flaws of worn multicoated carbide inserts using two important techniques namely scanning electron microscopy and atomic force microscopy. Finally, it is recommended a simple procedure for investigating manufacturing defects and flaws of worn inserts. Keywords—AFM, Coated inserts, Defects, SEM.

Although much research have been carried out to study and evaluate theory of metal cutting and ma... more Although much research have been carried out to study and evaluate theory of metal cutting and machining, unsatisfactory repetitive outcome was obtained with a wide domain of variability. Although numerical control (NC) technology of machine tools has contributed to the machining topic in terms of more flexibility, better surface quality and dimensional accuracy, and higher productivity, it still incapable to adapt to the dynamic conditions that result from continuous variations during cutting. Current CNC machines follow preprogrammed fixed feeds and speeds during each cutting segment. In contrast to NC procedures, adaptive control (AC) technique measures the process output (responses) in real time, and automatically adjusts and continuously tunes cutting feed and/or speed to the optimal levels during each operation so as to achieve some objectives under the imposed system constraints. In the current work, an adaptive control simulation strategy is proposed in which the core of the...

Advanced Materials Letters

SAE International Journal of Materials and Manufacturing

JOURNAL OF ENGINEERING RESEARCH, Kuwait University, 2018

In conventional numerical control machining, it is not possible to change the preset operating pa... more In conventional numerical control machining, it is not possible to change the preset operating parameters in the program during the machining cycle. In contrast, the adaptive control technique uses real-time sensing to continuously and instantaneously adjust the operative feed and/or the speed parameters to their optimal levels in order to ensure a more productive operation. In this study, a model-based adaptive control simulation strategy is proposed to optimize metal removal during rough turning by efficiently utilizing the available power resources within a safe machining environment. The approach is based on recursive continuous iterations to predict the instantaneous level of edge wear, together with the corresponding cutting forces and the consumed power, by considering the relevant models. The best speed-feed pair that provides the maximum metal removal rate without violating the imposed forces and power constraints is selected. Procedures are repeated for subsequent cut intervals by considering cumulative edge wear from preceding intervals until the accumulated edge wear level reaches the specified criterion value. The performance of the proposed model-based method was verified through comparisons with several conventional fixed-parameter wear-time methods. Results proved the superiority of the proposed AC disparate-parameter procedures in terms of noticeable greater productivity as the entire available machine power was exploited with a safe machining environment with reduced cost of the replacement cycle.

Hardness homogeneity of the commonly used structural ferrous and nonferrous engineering materials... more Hardness homogeneity of the commonly used structural ferrous and nonferrous engineering materials is of vital importance in the design stage, therefore, reliable information regarding material properties homogeneity should be validated and any deviation should be addressed. In the current study the hardness variation, over wide spectrum radial locations of some ferrous and nonferrous structural engineering materials, was investigated. Measurements were performed over both faces (cross-section) of each stock bar according to a pre-specified stratified design, ensuring the coverage of the entire area both in radial and circumferential directions. Additionally the credibility of the apparatus and measuring procedures were examined through a statistically based calibration process of the hardness reference block. Statistical and response surface graphical analysis are used to examine the nature, adequacy and significance of the measured hardness values. Calibration of the apparatus reference block proved the reliability of the measuring system, where no strong evidence was found against the stochastic nature of hardness measures over the various stratified locations. Also, outlier elimination procedures were proved to be beneficial only at fewer measured points. Hardness measurements showed a dispersion domain that is within the acceptable confidence interval. For AISI 4140 and AISI 1020 steels, hardness is found to have a slight decrease trend as the diameter is reduced, while an opposite behavior is observed for OPEN ACCESS Materials 2012, 5 13 AA 6082 aluminum alloy. However, no definite significant behavior was noticed regarding the effect of the sector sequence (circumferential direction).

Adaptive control (AC) of machine tools is the latest and most sophisticated technology in today's... more Adaptive control (AC) of machine tools is the latest and most sophisticated technology in today's manufacturing processes. Its ultimate object is to increase productivity through the optimal utilization of cutting parameters under system constraints. However, there are still many technical diculties delaying its practical implementation. Among these are the complexity and, sometimes, the inaccuracy of the measuring instrumentations, and the sluggishness of the system response. In this paper, an optimization algorithm for adaptive control systems is described that is based on interactive time-varying mathematical models. The main objective of the developed routine is to build software in which the mutual functional interrelation between cutting parameters in longitudinal rough turning operations and their pertinent outputs is organized to achieve some objective functions. The developed routine can be linked to a conventional AC structure to maximize the metal removal rate while maintaining tool wear and cutting force within the prespeci®ed levels. This is achieved via the instantaneous selection of the appropriate cutting parameters that usually govern the quality of the system outputs, especially speed and feed. Flex language syntax is used to integrate the developed mathematical models and optimization criteria to constitute the entire structure of the routine. Mathematical models are developed based on experimental data intended for a certain tool-workpiece-machine combination to cover a wide range of operating parameters that are usually used in rough turning. Objective criteria are speci®ed considering system productivity and safety targets. The developed algorithm has been tested in several runs considering di€erent ranges of cutting speed. Numerical results support the feasibility and the signi®cance of the proposed approach. At almost all speed levels, productivity is increased, especially at low to moderate levels that are usually used in practical rough turning operations and, fortunately, this is usually accompanied by the lowest wear rate.

International Journal of Machining and Machinability of Materials, 2013

Kuwait journal of science & engineering

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Kuwait journal of science & engineering

Product surface ®nish and its functional quality is a vital requirement and a crucial objective o... more Product surface ®nish and its functional quality is a vital requirement and a crucial objective of the manufacturing process. However, surface quality is a complicated parameter to assess and, therefore, it is usually judged using comparable rather than absolute measuring techniques. Surface roughness in machining is inevitable since it is associated with the static and dynamic characteristics of the di€erent elements of the cutting operations: tool-machine-workpart-cutting parameters. Moreover, it is not of a deterministic trend throughout the di€erent stages of a process since individual and overall characteristics are usually subjected to continuous variability. Therefore, surface quality is not only di€erent for di€erent products but a product quality is expected to be inhomogeneous among its di€erent zones. One of the major variability sources in machining that a€ect surface roughness is the di€erent inevitable modes of tool edge deformation. In the current work, the interrelat...

The importance of machining process in today’s industry requires the establishment of more practi... more The importance of machining process in today’s industry requires the establishment of more practical approaches to clearly represent the intimate and severe contact on the tool-chip-workpiece interfaces. Mathematical models are developed using the measured force signals to relate each of the tool-chip friction components on the rake face to the operating cutting parameters in rough turning operation using multilayers coated carbide inserts. Nonlinear modeling proved to have high capability to detect the nonlinear functional variability embedded in the experimental data. While feedrate is found to be the most influential parameter on the friction coefficient and its related force components, both cutting speed and depth of cut are found to have slight influence. Greater deformed chip thickness is found to lower the value of friction coefficient as the sliding length on the tool-chip interface is reduced.

DOAJ: Directory of Open Access Journals - DOAJ, 2022

Hardness of the widely used structural steel is of vital importance since it may help in the dete... more Hardness of the widely used structural steel is of vital importance since it may help in the determination of many mechanical properties of a material under loading situations. In order to obtain reliable information for design, properties homogeneity should be validated. In the current study the hardness variation over the different diameters of the same AISI 4140 bar is investigated. Measurements were taken on the two faces of the stock at equally spaced eight sectors and fifteen layers. Statistical and graphical analysis are performed to asses the distribution of hardness measurements over the specified area. Hardness measurements showed some degree of dispersion with about ± 10% of its nominal value provided by manufacturer. Hardness value is found to have a slight decrease trend as the diameter is reduced. However, an opposite behavior is noticed regarding the sequence of the sector indicating a nonuniform distribution over the same area either on the same face or considering t...

Applied Mechanics and Materials, 2014

The impact of the cutting parameters; speed, feed, and depth of cut on the wear and the life of t... more The impact of the cutting parameters; speed, feed, and depth of cut on the wear and the life of the cutting edge has long been a matter of debate among researchers. The cutting speed has long been agreed to have a prime influence in such a way that increasing speed leads to higher wear rate. Depth of cut has been concluded by majority of studies to have insignificant or negligible impact on edge wear and deformation. Despite its long established influence on the roughness of the machined surface, the effect of cutting feed on edge wear and deformation still requires more explanation. Cutting feed is a crucial parameter governing the product surface finish and dimensional accuracy and, therefore, its attitude during machining should be fully understood. This study presents experimental and modeling approach to detect the feed-wear functional interrelation considering various domains of the cutting speed. Results showed that the impact of the cutting feed is firmly associated with the...

Applied Mechanics and Materials, 2013

The determination of actual stresses over the tool-workpiece interface has long been a matter of ... more The determination of actual stresses over the tool-workpiece interface has long been a matter of debate among researchers. Evaluation of the nature and the geometry of the wear contact area were always associated with many, sometime impractical, assumptions. The indeterministic fashion of edge wear and deformation requires a more realistic way to predict the actual wear contact area. In the current study, many wear area patterns are proposed considering the different wear modes of the cutting edge. The selection of the most correlated pattern to a specific edge deformation is justified using the relevant variations in the radial and the axial force components. For a regular wear over the entire cutting edge, a wear pattern that considers nose and/or flank is justified. When the cutting edge plastically fails, a pattern that considers only nose wear is preferred. As the cutting edge is subjected to many types of irregular disturbances of edge fracture and chipping, a wear pattern con...

In conventional numerical control machining, it is not possible to change the preset operating pa... more In conventional numerical control machining, it is not possible to change the preset operating parameters in the program during the machining cycle. By contrast, the adaptive control technique uses real-time sensing to continuously and instantaneously adjust the operative feed and/or the speed parameters to their optimal levels in order to ensure a more productive operation. In this study, a model-based adaptive control simulation strategy is proposed to optimize metal removal during rough turning by efficiently utilizing the available power resources within a safe machining environment. The approach is based on recursive continuous iterations to predict the instantaneous level of edge wear, together with the corresponding cutting forces and the consumed power, by considering the relevant models. The best speed-feed pair that provides the maximum metal removal rate without violating the imposed forces and power constraints is selected. Procedures are repeated for subsequent cut inte...

Coated tool inserts can be considered as the backbone of machining processes due to their wear an... more Coated tool inserts can be considered as the backbone of machining processes due to their wear and heat resistance. However, defects of coating can degrade the integrity of these inserts and the number of these defects should be minimized or eliminated if possible. Recently, the advancement of coating processes and analytical tools open a new era for optimizing the coating tools. First, an overview is given regarding coating technology for cutting tool inserts. Testing techniques for coating layers properties, as well as the various coating defects and their assessment are also surveyed. Second, it is introduced an experimental approach to examine the possible coating defects and flaws of worn multicoated carbide inserts using two important techniques namely scanning electron microscopy and atomic force microscopy. Finally, it is recommended a simple procedure for investigating manufacturing defects and flaws of worn inserts. Keywords—AFM, Coated inserts, Defects, SEM.

Although much research have been carried out to study and evaluate theory of metal cutting and ma... more Although much research have been carried out to study and evaluate theory of metal cutting and machining, unsatisfactory repetitive outcome was obtained with a wide domain of variability. Although numerical control (NC) technology of machine tools has contributed to the machining topic in terms of more flexibility, better surface quality and dimensional accuracy, and higher productivity, it still incapable to adapt to the dynamic conditions that result from continuous variations during cutting. Current CNC machines follow preprogrammed fixed feeds and speeds during each cutting segment. In contrast to NC procedures, adaptive control (AC) technique measures the process output (responses) in real time, and automatically adjusts and continuously tunes cutting feed and/or speed to the optimal levels during each operation so as to achieve some objectives under the imposed system constraints. In the current work, an adaptive control simulation strategy is proposed in which the core of the...

Advanced Materials Letters

SAE International Journal of Materials and Manufacturing

JOURNAL OF ENGINEERING RESEARCH, Kuwait University, 2018

In conventional numerical control machining, it is not possible to change the preset operating pa... more In conventional numerical control machining, it is not possible to change the preset operating parameters in the program during the machining cycle. In contrast, the adaptive control technique uses real-time sensing to continuously and instantaneously adjust the operative feed and/or the speed parameters to their optimal levels in order to ensure a more productive operation. In this study, a model-based adaptive control simulation strategy is proposed to optimize metal removal during rough turning by efficiently utilizing the available power resources within a safe machining environment. The approach is based on recursive continuous iterations to predict the instantaneous level of edge wear, together with the corresponding cutting forces and the consumed power, by considering the relevant models. The best speed-feed pair that provides the maximum metal removal rate without violating the imposed forces and power constraints is selected. Procedures are repeated for subsequent cut intervals by considering cumulative edge wear from preceding intervals until the accumulated edge wear level reaches the specified criterion value. The performance of the proposed model-based method was verified through comparisons with several conventional fixed-parameter wear-time methods. Results proved the superiority of the proposed AC disparate-parameter procedures in terms of noticeable greater productivity as the entire available machine power was exploited with a safe machining environment with reduced cost of the replacement cycle.

Hardness homogeneity of the commonly used structural ferrous and nonferrous engineering materials... more Hardness homogeneity of the commonly used structural ferrous and nonferrous engineering materials is of vital importance in the design stage, therefore, reliable information regarding material properties homogeneity should be validated and any deviation should be addressed. In the current study the hardness variation, over wide spectrum radial locations of some ferrous and nonferrous structural engineering materials, was investigated. Measurements were performed over both faces (cross-section) of each stock bar according to a pre-specified stratified design, ensuring the coverage of the entire area both in radial and circumferential directions. Additionally the credibility of the apparatus and measuring procedures were examined through a statistically based calibration process of the hardness reference block. Statistical and response surface graphical analysis are used to examine the nature, adequacy and significance of the measured hardness values. Calibration of the apparatus reference block proved the reliability of the measuring system, where no strong evidence was found against the stochastic nature of hardness measures over the various stratified locations. Also, outlier elimination procedures were proved to be beneficial only at fewer measured points. Hardness measurements showed a dispersion domain that is within the acceptable confidence interval. For AISI 4140 and AISI 1020 steels, hardness is found to have a slight decrease trend as the diameter is reduced, while an opposite behavior is observed for OPEN ACCESS Materials 2012, 5 13 AA 6082 aluminum alloy. However, no definite significant behavior was noticed regarding the effect of the sector sequence (circumferential direction).

Adaptive control (AC) of machine tools is the latest and most sophisticated technology in today's... more Adaptive control (AC) of machine tools is the latest and most sophisticated technology in today's manufacturing processes. Its ultimate object is to increase productivity through the optimal utilization of cutting parameters under system constraints. However, there are still many technical diculties delaying its practical implementation. Among these are the complexity and, sometimes, the inaccuracy of the measuring instrumentations, and the sluggishness of the system response. In this paper, an optimization algorithm for adaptive control systems is described that is based on interactive time-varying mathematical models. The main objective of the developed routine is to build software in which the mutual functional interrelation between cutting parameters in longitudinal rough turning operations and their pertinent outputs is organized to achieve some objective functions. The developed routine can be linked to a conventional AC structure to maximize the metal removal rate while maintaining tool wear and cutting force within the prespeci®ed levels. This is achieved via the instantaneous selection of the appropriate cutting parameters that usually govern the quality of the system outputs, especially speed and feed. Flex language syntax is used to integrate the developed mathematical models and optimization criteria to constitute the entire structure of the routine. Mathematical models are developed based on experimental data intended for a certain tool-workpiece-machine combination to cover a wide range of operating parameters that are usually used in rough turning. Objective criteria are speci®ed considering system productivity and safety targets. The developed algorithm has been tested in several runs considering di€erent ranges of cutting speed. Numerical results support the feasibility and the signi®cance of the proposed approach. At almost all speed levels, productivity is increased, especially at low to moderate levels that are usually used in practical rough turning operations and, fortunately, this is usually accompanied by the lowest wear rate.

International Journal of Machining and Machinability of Materials, 2013

Kuwait journal of science & engineering

!"��� ��� ��# �$%���#���� ����� ���� & �$���� �� �� #��& �� � � �� �� ���������� %���#������... more !"��� ��� ��# �$%���#���� ����� ���� & �$���� �� �� #��& �� � � �� �� ���������� %���#������ �� �� � ��##�� %������� �� '���� %�� ������ �� �������� & ��� ��� ��#� ��� �� #������ �(����� %����) ���� ��%����� #������� %���#������ �� ���� �� �� ����#���) ��� �%��#� %����� �� "���� ��� � �� � �� '� ���� � ) "�� � ����� �� #���#�# %�� ������ ���� �� #�$�#�# %�� ������ ���� "����� ��� ��� ��� ��� ����� �%���*�������) �� � ��� '��� � �+���� & ��� �� � �� ��� ������� ��� &) �"� �� � ��� ��%���� ��� �� ���� ��� ���� ����� �� ������� ������� �� ������ �%��������, -�. ��� �������& � ���� #������'� ��& �� ��#�����) ��# *$� %���#����� ������ %���� ����) "��� ����' � %���#����� ���������� ��� �#�� � ) �� -��. ��� ��� �'� ��& � ��� � � #������'� ��& ��� ��# %���� ������� ������ %���� ���� �� � ���!���% #������� � � �� � ������+�� �� %��%��� �� ���*� �� ���#� �/� ��� ��� ������� *$� %���#����� #������'� ��& ��� �� ���� ��� ����� "�...

Kuwait journal of science & engineering

Product surface ®nish and its functional quality is a vital requirement and a crucial objective o... more Product surface ®nish and its functional quality is a vital requirement and a crucial objective of the manufacturing process. However, surface quality is a complicated parameter to assess and, therefore, it is usually judged using comparable rather than absolute measuring techniques. Surface roughness in machining is inevitable since it is associated with the static and dynamic characteristics of the di€erent elements of the cutting operations: tool-machine-workpart-cutting parameters. Moreover, it is not of a deterministic trend throughout the di€erent stages of a process since individual and overall characteristics are usually subjected to continuous variability. Therefore, surface quality is not only di€erent for di€erent products but a product quality is expected to be inhomogeneous among its di€erent zones. One of the major variability sources in machining that a€ect surface roughness is the di€erent inevitable modes of tool edge deformation. In the current work, the interrelat...

The importance of machining process in today’s industry requires the establishment of more practi... more The importance of machining process in today’s industry requires the establishment of more practical approaches to clearly represent the intimate and severe contact on the tool-chip-workpiece interfaces. Mathematical models are developed using the measured force signals to relate each of the tool-chip friction components on the rake face to the operating cutting parameters in rough turning operation using multilayers coated carbide inserts. Nonlinear modeling proved to have high capability to detect the nonlinear functional variability embedded in the experimental data. While feedrate is found to be the most influential parameter on the friction coefficient and its related force components, both cutting speed and depth of cut are found to have slight influence. Greater deformed chip thickness is found to lower the value of friction coefficient as the sliding length on the tool-chip interface is reduced.