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Wenxiang Zhao - One of the best experts on this subject based on the ideXlab platform.
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experimental study on brittle ductile Transition in elliptical ultrasonic assisted grinding euag of monocrystal sapphire using single diamond abrasive grain
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Zhiqiang Liang, Xibin Wang, Yongbo Wu, Li Jiao, Wenxiang ZhaoAbstract:Abstract This study is carried out to investigate the material removal characteristics in elliptical ultrasonic assisted grinding (EUAG) of monocrystal sapphire using single diamond abrasive grain. The scratching experiments are performed to develop a fundamental understanding of the ductile–brittle Transition mechanism during EUAG of monocrystal sapphire. An elliptical ultrasonic vibrator attached with a sapphire substrate was set up on a multi-axis CNC controlled machining center equipped with a single point diamond tool. The vibrator was constructed by bonding a piezoelectric ceramic device (PZT) having two separated electrodes on a metal elastic body, and an elliptical ultrasonic vibration was generated on the end-face of the metal elastic body when two phases of alternating current (AC) voltages with a phase difference are applied to their respective electrodes on PZT. In scratching experiments, the effects of ultrasonic vibration on the critical depth of cut a c for the ductile–brittle Transition region and the material removal ratio, i.e., the ratio of the removed material volume to the machined groove volume, f ab , are investigated by the examination of the scratching groove surfaces with SEM and AFM. The obtained results show that the critical depth of cut in EUAG is much larger than that in conventional grinding without vibration (CG), and even the bigger vibration amplitude leads to a greater improvement. Although the values of f ab in the ductile–brittle Transition region in both EUAG and CG are less than 1, that in EUAG is bigger than that in CG. Furthermore, as the vibration amplitude increases, the value of f ab is increased to eventually be close to 1. These show that it is prone to achieve a ductile mode grinding in greater vibration amplitude. It was also found that in the process there are two kinds of material removal modes, i.e., continuous cutting and discontinuous cutting modes, which are determined by the relationship between values of vibration amplitude and depth of cut. This study validates that the elliptical ultrasonic assisted grinding method is highly effective in ductile mode machining of hard and brittle materials.
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experimental study on brittle ductile Transition in elliptical ultrasonic assisted grinding euag of monocrystal sapphire using single diamond abrasive grain
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Zhiqiang Liang, Xibin Wang, Li Jiao, Lijing Xie, Wenxiang ZhaoAbstract:Abstract This study is carried out to investigate the material removal characteristics in elliptical ultrasonic assisted grinding (EUAG) of monocrystal sapphire using single diamond abrasive grain. The scratching experiments are performed to develop a fundamental understanding of the ductile–brittle Transition mechanism during EUAG of monocrystal sapphire. An elliptical ultrasonic vibrator attached with a sapphire substrate was set up on a multi-axis CNC controlled machining center equipped with a single point diamond tool. The vibrator was constructed by bonding a piezoelectric ceramic device (PZT) having two separated electrodes on a metal elastic body, and an elliptical ultrasonic vibration was generated on the end-face of the metal elastic body when two phases of alternating current (AC) voltages with a phase difference are applied to their respective electrodes on PZT. In scratching experiments, the effects of ultrasonic vibration on the critical depth of cut a c for the ductile–brittle Transition region and the material removal ratio, i.e., the ratio of the removed material volume to the machined groove volume, f ab , are investigated by the examination of the scratching groove surfaces with SEM and AFM. The obtained results show that the critical depth of cut in EUAG is much larger than that in conventional grinding without vibration (CG), and even the bigger vibration amplitude leads to a greater improvement. Although the values of f ab in the ductile–brittle Transition region in both EUAG and CG are less than 1, that in EUAG is bigger than that in CG. Furthermore, as the vibration amplitude increases, the value of f ab is increased to eventually be close to 1. These show that it is prone to achieve a ductile mode grinding in greater vibration amplitude. It was also found that in the process there are two kinds of material removal modes, i.e., continuous cutting and discontinuous cutting modes, which are determined by the relationship between values of vibration amplitude and depth of cut. This study validates that the elliptical ultrasonic assisted grinding method is highly effective in ductile mode machining of hard and brittle materials.
Donald R Paul - One of the best experts on this subject based on the ideXlab platform.
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polypropylene elastomer tpo nanocomposites 3 ductile brittle Transition temperature
Polymer, 2012Co-Authors: Rajkiran R Tiwari, Donald R PaulAbstract:Abstract Izod impact strength was determined as a function of temperature for polypropylene (PP)/ethylene-co-octene elastomer (EOR) blends and nanocomposites to determine the effect of PP molecular weight, elastomer MFI, EOR octene content and MMT content on the Ductile-Brittle (D-B) Transition temperature. The D-B Transition temperature decreases with increased molecular weight of the PP (H = high, M = medium and L = low) and the addition of MMT. The D-B Transition temperature also decreases as the elastomer particle size is decreased, and at a fixed elastomer particle sizes, the D-B Transition varies as H-PP
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comparison of the toughening behavior of nylon 6 versus an amorphous polyamide using various maleated elastomers
Polymer, 2006Co-Authors: Jijun Huang, Henno Keskkula, Donald R PaulAbstract:Abstract The toughening effect of two types of elastomers based on ethylene/α-olefin copolymers, viz, an ethylene/propylene copolymer (EPR) with its maleated version, EPR-g-MA, and an ethylene/1-octene copolymer (EOR) with its maleated versions, EOR-g-MA-X% (X=0.35, 1.6, 2.5), for two classes of polyamides: semi-crystalline nylon 6 versus an amorphous polyamide (Zytel 330 from DuPont), designated as a-PA, was explored. The results are compared with those reported earlier based on a styrenic triblock copolymer having a hydrogenated midblock, SEBS, and its maleated version, SEBS-g-MA, elastomer system. Izod impact strength was examined as a function of rubber content, rubber particle size and temperature. All three factors influence the impact behavior considerably for the two polyamide matrices. The a-PA is found to require a somewhat lower content of rubber for toughening than nylon 6. Very similar optimum ranges of rubber particle sizes were observed for ternary blends of EOR-g-MA/EOR with each of the two polyamides while blends based on mixtures of EPR-g-MA/EPR and SEBS-g-MA/SEBS (where the total rubber content is 20% by weight) show only an upper limit for a-PA but an optimum range of particle sizes for nylon 6 for effective toughening. Higher EPR-g-MA contents lead to lower ductile–brittle Transition temperatures (Tdb) as expected; however, a-PA binary blends with EPR-g-MA have a much lower Tdb than do nylon 6 blends when the content of the maleated elastomer is not high. A minimum in plots of ductile–brittle Transition temperature versus particle size appears for ternary blends of each of the matrices with EOR-g-MA/EOR; blends based on SEBS-g-MA/SEBS, in most cases, show higher ductile–brittle Transition temperatures, regardless of the matrix. However, blends with EPR-g-MA/EPR show comparable Tdb with those based on EOR-g-MA/EOR for the amorphous polyamide but show the lowest ductile–brittle Transition temperatures for nylon 6 within the range of particle sizes examined. For the blends with a bimodal size distribution, the global weight average rubber particle size is inappropriate for correlating the Izod impact strength and ductile–brittle Transition temperature. In general, trends for this amorphous polyamide are rather similar to those of semi-crystalline nylon 6.
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the role of matrix molecular weight in rubber toughened nylon 6 blends 3 ductile brittle Transition temperature
Polymer, 1996Co-Authors: A J Oshinski, Henno Keskkula, Donald R PaulAbstract:Abstract Izod impact strength was measured as a function of temperature for blends of nylon 6 with maleated and non-maleated styrene-hydrogenated butadiene-styrene triblock copolymers, SEBS, and ethylene/propylene random copolymers, EPR, to determine the effects of polyamide molecular weight, rubber type, and rubber particle size on the Ductile-Brittle Transition temperature. In general, the Ductile-Brittle Transition temperature decreases as the molecular weight of the nylon 6 matrix increases when compared at either constant maleic anhydride content of the rubber or at constant rubber particle size. Blends based on SEBS type elastomers with a standard styrene content never attain Ductile-Brittle Transition temperature below −20°C; whereas, blends generated with EPR type rubbers or a block copolymer of low styrene content can reach values as low as −50°C. This difference in Ductile-Brittle Transition temperature is related to the low temperature mechanical properties of the rubber phase.
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impact modified nylon 6 polypropylene blends 1 morphology property relationships
Polymer, 1995Co-Authors: A Gonzalezmontiel, Henno Keskkula, Donald R PaulAbstract:Abstract Two types of elastomers grafted with maleic anhydride (MA), an ethylene—propylene random copolymer (EPR) and a styrene—ethylene/butylene—styrene triblock copolymer (SEBS) were found to function both as impact modifiers and compatibilizers for nylon 6/polypropylene blends. The maleic anhydride grafted to the rubber reacts with the amine end-groups of the polyamide, forming a rubber-nylon 6 graft copolymer that locates at the interface between nylon 6 and polypropylene (PP) and thus acts as a compatibilizer. The SEBS-g-MA material appears to be the most effective compatibilizer. The two rubbers were equally effective for increasing room temperature toughness by dispersing in the nylon 6 phase of the blends. Lower Ductile-Brittle Transition temperatures are obtained when EPR-g-MA rubber is used, owing to its lower Tg and lower modulus at low temperatures compared to SEBS-g-MA rubber. Blend parameters such as rubber content, nylon 6/PP ratio and molecular weight of the components strongly influence the morphology and toughness of the blends. Low ductile—brittle Transition temperatures were obtained for blends in which any combination of the above parameters yielded a morphology where nylon 6 was the matrix phase with polypropylene and rubber finely dispersed in it, provided the component molecular weights were high enough to provide adequate intrinsic ductility.
Zhiqiang Liang - One of the best experts on this subject based on the ideXlab platform.
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experimental study on brittle ductile Transition in elliptical ultrasonic assisted grinding euag of monocrystal sapphire using single diamond abrasive grain
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Zhiqiang Liang, Xibin Wang, Yongbo Wu, Li Jiao, Wenxiang ZhaoAbstract:Abstract This study is carried out to investigate the material removal characteristics in elliptical ultrasonic assisted grinding (EUAG) of monocrystal sapphire using single diamond abrasive grain. The scratching experiments are performed to develop a fundamental understanding of the ductile–brittle Transition mechanism during EUAG of monocrystal sapphire. An elliptical ultrasonic vibrator attached with a sapphire substrate was set up on a multi-axis CNC controlled machining center equipped with a single point diamond tool. The vibrator was constructed by bonding a piezoelectric ceramic device (PZT) having two separated electrodes on a metal elastic body, and an elliptical ultrasonic vibration was generated on the end-face of the metal elastic body when two phases of alternating current (AC) voltages with a phase difference are applied to their respective electrodes on PZT. In scratching experiments, the effects of ultrasonic vibration on the critical depth of cut a c for the ductile–brittle Transition region and the material removal ratio, i.e., the ratio of the removed material volume to the machined groove volume, f ab , are investigated by the examination of the scratching groove surfaces with SEM and AFM. The obtained results show that the critical depth of cut in EUAG is much larger than that in conventional grinding without vibration (CG), and even the bigger vibration amplitude leads to a greater improvement. Although the values of f ab in the ductile–brittle Transition region in both EUAG and CG are less than 1, that in EUAG is bigger than that in CG. Furthermore, as the vibration amplitude increases, the value of f ab is increased to eventually be close to 1. These show that it is prone to achieve a ductile mode grinding in greater vibration amplitude. It was also found that in the process there are two kinds of material removal modes, i.e., continuous cutting and discontinuous cutting modes, which are determined by the relationship between values of vibration amplitude and depth of cut. This study validates that the elliptical ultrasonic assisted grinding method is highly effective in ductile mode machining of hard and brittle materials.
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experimental study on brittle ductile Transition in elliptical ultrasonic assisted grinding euag of monocrystal sapphire using single diamond abrasive grain
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Zhiqiang Liang, Xibin Wang, Li Jiao, Lijing Xie, Wenxiang ZhaoAbstract:Abstract This study is carried out to investigate the material removal characteristics in elliptical ultrasonic assisted grinding (EUAG) of monocrystal sapphire using single diamond abrasive grain. The scratching experiments are performed to develop a fundamental understanding of the ductile–brittle Transition mechanism during EUAG of monocrystal sapphire. An elliptical ultrasonic vibrator attached with a sapphire substrate was set up on a multi-axis CNC controlled machining center equipped with a single point diamond tool. The vibrator was constructed by bonding a piezoelectric ceramic device (PZT) having two separated electrodes on a metal elastic body, and an elliptical ultrasonic vibration was generated on the end-face of the metal elastic body when two phases of alternating current (AC) voltages with a phase difference are applied to their respective electrodes on PZT. In scratching experiments, the effects of ultrasonic vibration on the critical depth of cut a c for the ductile–brittle Transition region and the material removal ratio, i.e., the ratio of the removed material volume to the machined groove volume, f ab , are investigated by the examination of the scratching groove surfaces with SEM and AFM. The obtained results show that the critical depth of cut in EUAG is much larger than that in conventional grinding without vibration (CG), and even the bigger vibration amplitude leads to a greater improvement. Although the values of f ab in the ductile–brittle Transition region in both EUAG and CG are less than 1, that in EUAG is bigger than that in CG. Furthermore, as the vibration amplitude increases, the value of f ab is increased to eventually be close to 1. These show that it is prone to achieve a ductile mode grinding in greater vibration amplitude. It was also found that in the process there are two kinds of material removal modes, i.e., continuous cutting and discontinuous cutting modes, which are determined by the relationship between values of vibration amplitude and depth of cut. This study validates that the elliptical ultrasonic assisted grinding method is highly effective in ductile mode machining of hard and brittle materials.
Mustafizur Rahman - One of the best experts on this subject based on the ideXlab platform.
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A model to predict the critical undeformed chip thickness in vibration-assisted machining of brittle materials
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Xinquan Zhang, Kui Liu, Muhammad Arif, A. Senthil Kumar, Mustafizur RahmanAbstract:Abstract Vibration-assisted machining (VAM) of brittle materials has been proved to be useful in improving the machining performance by significantly increasing the critical undeformed chip thickness for ductile–brittle Transition. However, until now, there does not exist any viable method or model to predict the critical undeformed chip thickness in VAM of brittle materials. The authors have already presented a specific-cutting-energy based model to predict the ductile–brittle Transition in nano-machining of brittle materials. In the current study, the specific-cutting-energy based model is extended for VAM by taking into account the vibration parameters in addition to the work-material intrinsic properties, tool geometry and machining parameters in predicting the critical undeformed chip thickness. A series of cutting tests on single crystal silicon workpiece, using single crystal diamond with varying nominal cutting speeds, are conducted to verify the proposed model. It is found that the predicted results are in good agreement with the experimental results.
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a predictive model of the critical undeformed chip thickness for ductile brittle Transition in nano machining of brittle materials
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Muhammad Arif, Mustafizur Rahman, Zhang Xinquan, Senthil KumarAbstract:Abstract There is a distinct Transition in the mode of material removal in machining of brittle materials if the undeformed chip thickness is below a critical threshold of submicron scale. It is believed that at such small scale of material removal, the energy required to extend pre-existing flaws in the microstructure of brittle material exceeds the energy required to mobilize the micro-structural dislocations and hence plastic deformation serves as the dominant mode of material removal. It is postulated that a Transition in the mode of material removal in machining of brittle materials is accompanied by a corresponding shift in the representative mode of energy expenditure. Hence, machining energy is a viable parameter to characterize the modes of material removal in machining of a brittle material. This paper presents a specific cutting-energy based model to predict the ductile–brittle Transition point in ultra-precision machining of brittle materials. The energy expended in brittle and ductile modes of machining is modeled as a function of work-material intrinsic properties, tool geometry and process parameters. The Transition point is identified in terms of undeformed chip thickness at which the mode of energy undergoes a Transition from the plastic deformation based one to the fracture based one. The validity of the proposed model is verified by single-edge cutting tests on single-crystal silicon and BK7 glass. The experimental results are found in good agreement with model results.
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A study on the effect of tool-edge radius on critical machining characteristics in ultra-precision milling of tungsten carbide
The International Journal of Advanced Manufacturing Technology, 2012Co-Authors: Muhammad Arif, Mustafizur Rahman, Wong Yoke SanAbstract:A crack-free surface can be finished on brittle materials by a specialized but traditional machining technique known as ductile-mode machining. In ductile-mode machining of brittle material, crack propagation is suppressed by selecting a suitable combination of tool and machining parameters leading to the removal of material through plastic deformation enabled by dislocation motion. In ductile-mode machining, the tool–workpiece interaction is of critical significance for the capability of the cutting process to finish a crack-free surface on a brittle material. This interaction is largely dictated by the cutting-edge radius of the tool when the undeformed chip thickness is comparable to the edge radius as is the case of ductile-mode machining. This paper presents the experimental results of ductile-mode milling of tungsten carbide to investigate the effect of cutting-edge radius on certain critical machining characteristics associated with the ductile–brittle Transition specific to milling process of brittle material. The experimental results have established that an increase in the cutting-edge radius within a certain range increases the critical feed per edge leading to the improvement of material removal rate in ductile-mode milling. An increasingly negative effective rake angle is desired during milling with larger edge-radiused tool to suppress the crack propagation in the cutting zone to achieve ductile-mode machining. The results also identify the effect of the edge radius on certain other parameters such as critical specific cutting energy, plowing effect and subsurface damage depth to comprehend the ductile–brittle Transition phenomenon in ductile-mode milling.
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a model to determine the effect of tool diameter on the critical feed rate for ductile brittle Transition in milling process of brittle material
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2012Co-Authors: Muhammad Arif, Mustafizur RahmanAbstract:This paper presents analytical and experimental results of ductile-mode machining of brittle material by milling process. In milling process of brittle material, feed per edge is the predominant parameter to achieve ductile-mode machining and hence it limits the permissible material removal rate. An analytical model has been proposed to evaluate the effect of tool diameter on the critical feed per edge for Ductile-Brittle Transition in milling process of brittle material. The proposed model has been validated experimentally by performing microcutting tests on tungsten carbide workpiece by milling process. It has been established by the model and the experimental results that an end-mill of larger diameter improves the critical feed per edge for Ductile-Brittle Transition in milling process of brittle material.
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an experimental study on the machining characteristics in ductile mode milling of bk 7 glass
The International Journal of Advanced Manufacturing Technology, 2012Co-Authors: Muhammad Arif, Mustafizur Rahman, Wong Yoke SanAbstract:Glass is considered as one of the most challenging materials to machine because of its high hardness coupled with high brittleness. The challenge, in machining such a brittle material, lies in achieving the material removal through plastic deformation rather than characteristic brittle fracture. It has already been established that every brittle material, no matter how brittle it is, can be machined in ductile mode under certain critical conditions. The critical conditions are material specific, and hence, every material tends to show unique behavior in terms of critical conditions during machining process. This paper outlines the results of an experimental study to determine the critical chip thickness for ductile–brittle Transition, chip morphology, and the effect of cutting speed on the critical conditions in peripheral milling process of BK-7 glass. It is established experimentally that the cutting speed affects the chip morphology, machined surface quality, and critical conditions due to possible thermal effects in such a way that ductile–brittle Transition phenomenon is facilitated at high cutting speeds.
Muhammad Arif - One of the best experts on this subject based on the ideXlab platform.
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A model to predict the critical undeformed chip thickness in vibration-assisted machining of brittle materials
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Xinquan Zhang, Kui Liu, Muhammad Arif, A. Senthil Kumar, Mustafizur RahmanAbstract:Abstract Vibration-assisted machining (VAM) of brittle materials has been proved to be useful in improving the machining performance by significantly increasing the critical undeformed chip thickness for ductile–brittle Transition. However, until now, there does not exist any viable method or model to predict the critical undeformed chip thickness in VAM of brittle materials. The authors have already presented a specific-cutting-energy based model to predict the ductile–brittle Transition in nano-machining of brittle materials. In the current study, the specific-cutting-energy based model is extended for VAM by taking into account the vibration parameters in addition to the work-material intrinsic properties, tool geometry and machining parameters in predicting the critical undeformed chip thickness. A series of cutting tests on single crystal silicon workpiece, using single crystal diamond with varying nominal cutting speeds, are conducted to verify the proposed model. It is found that the predicted results are in good agreement with the experimental results.
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a predictive model of the critical undeformed chip thickness for ductile brittle Transition in nano machining of brittle materials
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Muhammad Arif, Mustafizur Rahman, Zhang Xinquan, Senthil KumarAbstract:Abstract There is a distinct Transition in the mode of material removal in machining of brittle materials if the undeformed chip thickness is below a critical threshold of submicron scale. It is believed that at such small scale of material removal, the energy required to extend pre-existing flaws in the microstructure of brittle material exceeds the energy required to mobilize the micro-structural dislocations and hence plastic deformation serves as the dominant mode of material removal. It is postulated that a Transition in the mode of material removal in machining of brittle materials is accompanied by a corresponding shift in the representative mode of energy expenditure. Hence, machining energy is a viable parameter to characterize the modes of material removal in machining of a brittle material. This paper presents a specific cutting-energy based model to predict the ductile–brittle Transition point in ultra-precision machining of brittle materials. The energy expended in brittle and ductile modes of machining is modeled as a function of work-material intrinsic properties, tool geometry and process parameters. The Transition point is identified in terms of undeformed chip thickness at which the mode of energy undergoes a Transition from the plastic deformation based one to the fracture based one. The validity of the proposed model is verified by single-edge cutting tests on single-crystal silicon and BK7 glass. The experimental results are found in good agreement with model results.
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A study on the effect of tool-edge radius on critical machining characteristics in ultra-precision milling of tungsten carbide
The International Journal of Advanced Manufacturing Technology, 2012Co-Authors: Muhammad Arif, Mustafizur Rahman, Wong Yoke SanAbstract:A crack-free surface can be finished on brittle materials by a specialized but traditional machining technique known as ductile-mode machining. In ductile-mode machining of brittle material, crack propagation is suppressed by selecting a suitable combination of tool and machining parameters leading to the removal of material through plastic deformation enabled by dislocation motion. In ductile-mode machining, the tool–workpiece interaction is of critical significance for the capability of the cutting process to finish a crack-free surface on a brittle material. This interaction is largely dictated by the cutting-edge radius of the tool when the undeformed chip thickness is comparable to the edge radius as is the case of ductile-mode machining. This paper presents the experimental results of ductile-mode milling of tungsten carbide to investigate the effect of cutting-edge radius on certain critical machining characteristics associated with the ductile–brittle Transition specific to milling process of brittle material. The experimental results have established that an increase in the cutting-edge radius within a certain range increases the critical feed per edge leading to the improvement of material removal rate in ductile-mode milling. An increasingly negative effective rake angle is desired during milling with larger edge-radiused tool to suppress the crack propagation in the cutting zone to achieve ductile-mode machining. The results also identify the effect of the edge radius on certain other parameters such as critical specific cutting energy, plowing effect and subsurface damage depth to comprehend the ductile–brittle Transition phenomenon in ductile-mode milling.
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a model to determine the effect of tool diameter on the critical feed rate for ductile brittle Transition in milling process of brittle material
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2012Co-Authors: Muhammad Arif, Mustafizur RahmanAbstract:This paper presents analytical and experimental results of ductile-mode machining of brittle material by milling process. In milling process of brittle material, feed per edge is the predominant parameter to achieve ductile-mode machining and hence it limits the permissible material removal rate. An analytical model has been proposed to evaluate the effect of tool diameter on the critical feed per edge for Ductile-Brittle Transition in milling process of brittle material. The proposed model has been validated experimentally by performing microcutting tests on tungsten carbide workpiece by milling process. It has been established by the model and the experimental results that an end-mill of larger diameter improves the critical feed per edge for Ductile-Brittle Transition in milling process of brittle material.
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an experimental study on the machining characteristics in ductile mode milling of bk 7 glass
The International Journal of Advanced Manufacturing Technology, 2012Co-Authors: Muhammad Arif, Mustafizur Rahman, Wong Yoke SanAbstract:Glass is considered as one of the most challenging materials to machine because of its high hardness coupled with high brittleness. The challenge, in machining such a brittle material, lies in achieving the material removal through plastic deformation rather than characteristic brittle fracture. It has already been established that every brittle material, no matter how brittle it is, can be machined in ductile mode under certain critical conditions. The critical conditions are material specific, and hence, every material tends to show unique behavior in terms of critical conditions during machining process. This paper outlines the results of an experimental study to determine the critical chip thickness for ductile–brittle Transition, chip morphology, and the effect of cutting speed on the critical conditions in peripheral milling process of BK-7 glass. It is established experimentally that the cutting speed affects the chip morphology, machined surface quality, and critical conditions due to possible thermal effects in such a way that ductile–brittle Transition phenomenon is facilitated at high cutting speeds.
