The Experts below are selected from a list of 21714 Experts worldwide ranked by ideXlab platform
Matthew S Dargusch - One of the best experts on this subject based on the ideXlab platform.
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effect of tool wear evolution on Chip Formation during dry machining of ti 6al 4v alloy
International Journal of Machine Tools & Manufacture, 2018Co-Authors: Matthew S Dargusch, Shoujin Sun, Jiwon Kim, Patrick Trimby, Julie M CairneyAbstract:Abstract The complex microstructure of segmented Chips and the changing deFormation mechanisms during the machining of the Ti-6Al-4V alloy for a given cutting tool have been explored. Chip geometry and microstructure were investigated for increasing volumes of material removed at a cutting speed at which the tool characteristically develops gradual flank wear. The degree of Chip segmentation and deFormation mode changed significantly as machining progressed from using a new tool towards a worn tool. Chip Formation processes when machining near the end of the cutting tool life is characterised by increasing amounts of twinning formed through both tension and compression.
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sph fe modeling of cutting force and Chip Formation during thermally assisted machining of ti6al4v alloy
Computational Materials Science, 2014Co-Authors: M J Bermingham, Gui Wang, Matthew S DarguschAbstract:Abstract SPH method was employed in this study to develop machining models to study the thermally assisted machining of Ti6Al4V process. Both 2D and 3D models were developed for investigations of Chip Formation and cutting force, respectively. Two sets of machining parameters under four different target initial workpiece temperatures were simulated. Corresponding thermally assisted machining experiments were conducted for the validation of the models. The influence of the initial workpiece temperature on the Chip Formation and cutting force was studied. The Chip Formation mechanism and its relationship with the cyclic cutting force were also discussed.
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finite element modeling of cutting force and Chip Formation during thermally assisted machining of ti6al4v alloy
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2013Co-Authors: M J Bermingham, Gui Wang, Matthew S DarguschAbstract:The improvement in machinability during thermally assisted turning of the Ti-6Al-4V alloy has been investigated using finite element modeling. A 2D thermally assisted turning model was developed and validated by comparing the simulation results with experimental results. The effect of workpiece temperature on the cutting force and Chip Formation process was examined. The predicted cutting forces and Chip morphologies from the simulation strongly correlated with the experimental results. It was observed from the simulation that the Chip forms after the coalescence of two deformed regions in the shear band and that the cyclic cutting forces are strongly related to this Chip Formation process.
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the effect of a laser beam on Chip Formation during machining of ti6al4v alloy
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2010Co-Authors: Shoujin Sun, Milan Brandt, Matthew S DarguschAbstract:The effect of the laser beam on Chip Formation when machining Ti6Al4V alloy has been investigated at different cutting speeds and laser powers. The characteristics of the segmented Chip produced by laser-assisted machining (LAM) in terms of the tooth depth and tooth spacing were strongly dependent on the cutting speed and laser power. Two types of segmented Chip Formation processes were observed, one at low and the other at high cutting speeds with a continuous Chip occurring between these two types of segmented Chips. The critical cutting speed at which the transition from the sharp, segmented Chip to the continuous Chip occurred increased with laser power. To obtain the continuous Chip, plastic deFormation at the shear zone to match the deFormation strain introduced by the cutting tool is required. This can be achieved by laser heating the material in front of the cutting tool. A physical model is proposed to explain qualitatively the Chip segmentation in conventional machining and the continuous Chip transition at high cutting speed with the application of a laser beam.
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characteristics of cutting forces and Chip Formation in machining of titanium alloys
International Journal of Machine Tools & Manufacture, 2009Co-Authors: Matthew S Dargusch, Shoujin Sun, Milan BrandtAbstract:Abstract Chip Formation during dry turning of Ti6Al4V alloy has been examined in association with dynamic cutting force measurements under different cutting speeds, feed rates and depths of cut. Both continuous and segmented Chip Formation processes were observed in one cut under conditions of low cutting speed and large feed rate. The slipping angle in the segmented Chip was 55°, which was higher than that in the continuous Chip (38°). A cyclic force was produced during the Formation of segmented Chips and the force frequency was the same as the Chip segmentation frequency. The peak of the cyclic force when producing segmented Chips was 1.18 times that producing the continuous Chip. The undeformed surface length in the segmented Chip was found to increase linearly with the feed rate but was independent of cutting speed and depth of cut. The cyclic force frequency increased linearly with cutting speed and decreased inversely with feed rate. The cutting force increased with the feed rate and depth of cut at constant cutting speed due to the large volume of material being removed. The increase in cutting force with increasing cutting speed from 10 to 16 and 57 to 75 m/min was attributed to the strain rate hardening at low and high strain rates, respectively. The decrease in cutting force with increasing cutting speed outside these speed ranges was due to the thermal softening of the material. The amplitude variation of the high-frequency cyclic force associated with the segmented Chip Formation increased with increasing depth of cut and feed rate, and decreased with increasing cutting speed from 57 m/min except at the cutting speeds where harmonic vibration of the machine occurs.
Yue Xian Song - One of the best experts on this subject based on the ideXlab platform.
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research on the Chip Formation mechanism during the high speed milling of hardened steel
International Journal of Machine Tools & Manufacture, 2014Co-Authors: Cheng Yong Wang, Lijuan Zheng, Dewen Tang, Yue Xian SongAbstract:Abstract An easy-to-produce sawtooth Chip is the main feature of the high-speed milling process for hardened steel. This Chip may lead to a high-frequency periodic fluctuation of the cutting force and accelerate the tool׳s wear rate. This study investigated the process of Chip Formation and the change in Chip morphology during the high-speed milling of hardened steel (51, 62 HRC). The Formation condition of continuous and sawtooth Chips and various characteristics of the sawtooth Chip, such as cutting speed, feed rate, axial depth of cut, and others, were also studied. The results showed that the Chip of materials with different hardnesses could be controlled as a continuous Chip through the optimisation of a combination of cutting speed, feed per tooth, and cutting depth. If the feed per tooth and axial depth of the cut were too large within the range of proper cutting speeds generated by a continuous Chip, the Chip morphology turned into a sawtooth. Increasing the cutting speed during the cutting process not only strengthened the material׳s hardness but also increased the local temperature of the shear band rapidly and aggravated the material׳s heat softness. When these parameters became balanced, the shear deFormation became highly localised in the shear band and resulted in adiabatic shear. A quantitative evaluation of the sawtooth-shaped Chip׳s deFormation degree was performed using the cross-sectional area and angle of the sawtooth Chip. By establishing a geometric model of the sawtooth Chip Formation during the high-speed milling of hardened steel, that was used to predict the shear strain and strain rate during Chip Formation, the range of shear angles generating a sawtooth Chip was calculated to be 40–60°.
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finite element simulation of Chip Formation during high speed peripheral milling of hardened mold steel
Key Engineering Materials, 2010Co-Authors: De Weng Tang, Cheng Yong Wang, Ying Ning Hu, Yue Xian SongAbstract:The modeling and simulation of Chip Formation during high speed milling of hardened mold steel are systematically studied by the Finite Element Analysis (FEA). The modified Johnson-Cook’s constitutive equation for hardened mold steel is introduced. Comparing to the experimental results, the simulated results of cutting force, Chip morphology, effective stress and cutting temperature in deFormation zones of high speed peripheral milling indicate good consistence and the models established can be used to accurately predict the behavior of hardened mold steel.
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finite element simulation of Chip Formation during high speed peripheral milling of hardened mold steel
Key Engineering Materials, 2010Co-Authors: De Weng Tang, Cheng Yong Wang, Yue Xian SongAbstract:The modeling and simulation of Chip Formation during high speed milling of hardened mold steel are systematically studied by the Finite Element Analysis (FEA). The modified Johnson-Cook’s constitutive equation for hardened mold steel is introduced. Comparing to the experimental results, the simulated results of cutting force, Chip morphology, effective stress and cutting temperature in deFormation zones of high speed peripheral milling indicate good consistence and the models established can be used to accurately predict the behavior of hardened mold steel.
Shoujin Sun - One of the best experts on this subject based on the ideXlab platform.
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effect of tool wear evolution on Chip Formation during dry machining of ti 6al 4v alloy
International Journal of Machine Tools & Manufacture, 2018Co-Authors: Matthew S Dargusch, Shoujin Sun, Jiwon Kim, Patrick Trimby, Julie M CairneyAbstract:Abstract The complex microstructure of segmented Chips and the changing deFormation mechanisms during the machining of the Ti-6Al-4V alloy for a given cutting tool have been explored. Chip geometry and microstructure were investigated for increasing volumes of material removed at a cutting speed at which the tool characteristically develops gradual flank wear. The degree of Chip segmentation and deFormation mode changed significantly as machining progressed from using a new tool towards a worn tool. Chip Formation processes when machining near the end of the cutting tool life is characterised by increasing amounts of twinning formed through both tension and compression.
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the effect of a laser beam on Chip Formation during machining of ti6al4v alloy
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2010Co-Authors: Shoujin Sun, Milan Brandt, Matthew S DarguschAbstract:The effect of the laser beam on Chip Formation when machining Ti6Al4V alloy has been investigated at different cutting speeds and laser powers. The characteristics of the segmented Chip produced by laser-assisted machining (LAM) in terms of the tooth depth and tooth spacing were strongly dependent on the cutting speed and laser power. Two types of segmented Chip Formation processes were observed, one at low and the other at high cutting speeds with a continuous Chip occurring between these two types of segmented Chips. The critical cutting speed at which the transition from the sharp, segmented Chip to the continuous Chip occurred increased with laser power. To obtain the continuous Chip, plastic deFormation at the shear zone to match the deFormation strain introduced by the cutting tool is required. This can be achieved by laser heating the material in front of the cutting tool. A physical model is proposed to explain qualitatively the Chip segmentation in conventional machining and the continuous Chip transition at high cutting speed with the application of a laser beam.
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characteristics of cutting forces and Chip Formation in machining of titanium alloys
International Journal of Machine Tools & Manufacture, 2009Co-Authors: Matthew S Dargusch, Shoujin Sun, Milan BrandtAbstract:Abstract Chip Formation during dry turning of Ti6Al4V alloy has been examined in association with dynamic cutting force measurements under different cutting speeds, feed rates and depths of cut. Both continuous and segmented Chip Formation processes were observed in one cut under conditions of low cutting speed and large feed rate. The slipping angle in the segmented Chip was 55°, which was higher than that in the continuous Chip (38°). A cyclic force was produced during the Formation of segmented Chips and the force frequency was the same as the Chip segmentation frequency. The peak of the cyclic force when producing segmented Chips was 1.18 times that producing the continuous Chip. The undeformed surface length in the segmented Chip was found to increase linearly with the feed rate but was independent of cutting speed and depth of cut. The cyclic force frequency increased linearly with cutting speed and decreased inversely with feed rate. The cutting force increased with the feed rate and depth of cut at constant cutting speed due to the large volume of material being removed. The increase in cutting force with increasing cutting speed from 10 to 16 and 57 to 75 m/min was attributed to the strain rate hardening at low and high strain rates, respectively. The decrease in cutting force with increasing cutting speed outside these speed ranges was due to the thermal softening of the material. The amplitude variation of the high-frequency cyclic force associated with the segmented Chip Formation increased with increasing depth of cut and feed rate, and decreased with increasing cutting speed from 57 m/min except at the cutting speeds where harmonic vibration of the machine occurs.
Gerry Byrne - One of the best experts on this subject based on the ideXlab platform.
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Dynamics of Chip Formation during orthogonal cutting of titanium alloy Ti-6Al-4V
Cirp Annals-manufacturing Technology, 2008Co-Authors: Mike Cotterell, Gerry ByrneAbstract:Abstract Polished and etched disks of titanium alloy Ti–6Al–4V were machined in a series of continuous and interrupted orthogonal cutting tests on a specially adapted lathe. A high-speed imaging system with a microscope lens and strobed copper-vapour laser illumination system enabled direct observation of the Chip Formation zone at a recording rate of 24,000 frames/s. The Chip Formation cycle was recorded for cutting speeds from 4 to 140 m/min. Segmented Chips were observed throughout. Image analysis of the recorded video sequences examined the resulting Chip segment geometry, the segmentation frequency and the critical strain required to initiate shear band Formation.
D Lennon - One of the best experts on this subject based on the ideXlab platform.
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observations on Chip Formation and acoustic emission in machining ti 6al 4v alloy
International Journal of Machine Tools & Manufacture, 2001Co-Authors: J Barry, G Byrne, D LennonAbstract:Abstract Orthogonal cutting tests were undertaken to investigate the mechanisms of Chip Formation for a Ti–6Al–4V alloy and to assess the influences of such on acoustic emission (AE). Within the range of conditions employed (cutting speed, v c =0.25–3.0 m/s , feed, f=20–100 μm ), saw-tooth Chips were produced. A transition from aperiodic to periodic saw-tooth Chip Formation occurring with increases in cutting speed and/or feed. Examination of Chips formed shortly after the instant of tool engagement, where the undeformed Chip thickness is slightly greater than the minimum undeformed Chip thickness, revealed a continuous Chip characterised by the presence of fine lamellae on its free surface. In agreement with the consensus that shear localisation in machining Ti and its alloys is due to the occurrence of a thermo-plastic instability, the underside of saw-tooth segments formed at relatively high cutting speeds, exhibiting evidence of ductile fracture. Chips formed at lower cutting speeds suggest that cleavage is the mechanism of catastrophic failure, at least within the upper region of the primary shear zone. An additional characteristic of machining Ti–6Al–4V alloy at high cutting speeds is the occurrence of welding between the Chip and the tool. Fracture of such welds appears to be the dominant source of AE. The results are discussed with reference to the machining of hardened steels, another class of materials from which saw-tooth Chips are produced.