Hard Turning: Chip Formation Mechanisms and Metallurgical Aspects

1999 ◽  
Vol 122 (3) ◽  
pp. 406-412 ◽  
Author(s):  
Ge´rard Poulachon ◽  
Alphonse L. Moisan
Keyword(s):  
Crack Initiation ◽  
Chip Formation ◽  
Hard Turning ◽  
Theoretical Study ◽  
Formation Mechanisms ◽  
Stick Slip ◽  
Chip Geometry ◽  
Hardness Values ◽  
Cutting Speeds ◽  
Made In

A 100Cr6 (AISI E52100) steel in the hardness range of 180 to 750 HV10 was machined. Quick stop tests were carried out at various hardness values to observe the different chip formation mechanisms. A limit was found between the shearing and cracking chip formation. Experiments on the selected steel at 750 HV10 were carried out at various cutting speeds and feed rates. The “saw tooth chips” obtained were examined geometrically and metallurgically on longitudinal midsections. A relationship has been established between the chip geometry and the cutting conditions. A theoretical study of the chip shape was made, in particular its thickness. The friction stick slip velocities, and the segment apparition frequency were calculated. Each stage of the chip formation could be observed on each micrograph of Q.S.T, especially the crack initiation. A discussion on the apparition of the thin white layers is also proposed. [S1087-1357(00)01502-1]

Hard Turning: Chip Formation Mechanisms and Metallurgical Aspects

1999 ◽  
Author(s):  
Gérard Poulachon ◽  
Alphonse L. Moisan
Keyword(s):  
Crack Initiation ◽  
Chip Formation ◽  
Hard Turning ◽  
Theoretical Study ◽  
Formation Mechanisms ◽  
Stick Slip ◽  
Chip Geometry ◽  
Hardness Values ◽  
Cutting Speeds ◽  
Made In

Abstract A 100Cr6 (AISI E52100) steel in the hardness range of 180 to 750 HV10 was machined. Quick stop tests were carried out at various hardness values to observe the different chip formation mechanisms. A limit was found between the shearing and cracking chip formation. Experiments on the selected steel at 750 HV10 were carried out at various cutting speeds and feed rates. The “saw tooth chips” obtained were examined geometrically and metallurgically on longitudinal midsections. A relationship has been established between the chip geometry and the cutting conditions. A theoretical study of the chip shape was made, in particular its thickness. The friction stick slip velocities, and the segment apparition frequency were calculated. Each stage of the chip formation could be observed on each micrograph of Q.S.T, especially the crack initiation. A discussion on the apparition of the thin white layers is also proposed.

scholarly journals Comparative Study of Chip Formation in Orthogonal and Oblique Slow-Rate Machining of EN 16MnCr5 Steel

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 698 ◽  
Author(s):  
Monkova ◽  
Monka ◽  
Sekerakova ◽  
Hruzik ◽  
Burecek ◽  
...  
Keyword(s):  
Chip Formation ◽  
Slow Rate ◽  
Material Removal ◽  
Cutting Tool ◽  
Tool Geometry ◽  
Formation Mechanisms ◽  
Machined Surface ◽  
Thermal Influence ◽  
Microstructure Of Material ◽  
Made In

In today’s unmanned productions systems, it is very important that the manufacturing processes are carried out efficiently and smoothly. Therefore, controlling chip formation becomes an essential issue to be dealt with. It can be said that the material removal from a workpiece using machining is based on the degradation of material cohesion made in a controlled manner. The aim of the study was to understand the chip formation mechanisms that can, during uncontrolled processes, result in the formation and propagation of microcracks on the machined surface and, as such, cause failure of a component during its operation. This article addresses some aspects of chip formation in the orthogonal and oblique slow-rate machining of EN 16MnCr5 steel. In order to avoid chip root deformation and its thermal influence on sample acquisition, that could cause the changes in the microstructure of material, a new reliable method for sample acquisition has been developed in this research. The results of the experiments have been statistically processed. The obtained dependencies have uncovered how the cutting tool geometry and cutting conditions influence a chip shape, temperature in cutting area, or microhardness according to Vickers in the area of shear angle.

scholarly journals Effect of cutting speed on chip formation and wear mechanisms of coated carbide tools when ultra-high-speed face milling titanium alloy Ti-6Al-4V

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771370 ◽  
Author(s):  
Anhai Li ◽  
Jun Zhao ◽  
Guanming Hou
Keyword(s):  
Tool Wear ◽  
Chip Formation ◽  
Wear Mechanisms ◽  
Failure Mechanisms ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Face Milling ◽  
Formation Mechanisms ◽  
Tool Wear Mechanisms ◽  
Cutting Speeds

Chip morphology and its formation mechanisms, cutting force, cutting power, specific cutting energy, tool wear, and tool wear mechanisms at different cutting speeds of 100–3000 m/min during dry face milling of Ti-6Al-4V alloy using physical vapor deposition-(Ti,Al)N-TiN-coated cemented carbide tools were investigated. The cutting speed was linked to the chip formation process and tool failure mechanisms of the coated cemented cutting tools. Results revealed that the machined chips exhibited clear saw-tooth profile and were almost segmented at high cutting speeds, and apparent degree of saw-tooth chip morphology occurred as cutting speed increased. Abrasion in the flank face, the adhered chips on the wear surface, and even melt chips were the most typical wear forms. Complex and synergistic interactions among abrasive wear, coating delamination, adhesive wear, oxidation wear, and thermal mechanical–mechanical impacts were the main wear or failure mechanisms. As the cutting speed was very high (>2000 m/min), discontinuous or fragment chips and even melt chips were produced, but few chips can be collected because the chips easily burned under the extremely high cutting temperature. Large area flaking, extreme abrasion, and serious adhesion dominated the wear patterns, and the tool wear mechanisms were the interaction of thermal wear and mechanical wear or failure under the ultra-high frequency and strong impact thermo-mechanical loads.

Study of Chip Morphology and Chip Formation Mechanism During Machining of Magnesium-Based Metal Matrix Composites

2017 ◽  
Author(s):  
Brian Davis ◽  
David Dabrow ◽  
Licheng Ju ◽  
Anhai Li ◽  
Chengying Xu ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Formation Mechanism ◽  
Chip Formation ◽  
Metal Matrix ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Matrix Composites ◽  
Particle Type ◽  
Chip Formation Mechanism ◽  
Cutting Speeds

Magnesium (Mg) and its alloys are among the lightest metallic structural materials, making them very attractive for use in the aerospace and automotive industries. Recently, Mg has been used in metal matrix composites (MMCs), demonstrating significant improvements in mechanical performance. However, the machinability of Mg-based MMCs is still largely elusive. In this study, Mg-based MMCs are machined using a wide range of cutting speeds in order to elucidate both the chip morphology and chip formation mechanism. Cutting speed is found to have the most significant influence on both the chip morphology and chip formation mechanism, with the propensity of discontinuous, particle-type chip formation increasing as the cutting speed increases. Saw-tooth chips are found to be the primary chip morphology at low cutting speeds (lower than 0.5 m/s), while discontinuous, particle-type chips prevail at high cutting speeds (higher than 1.0 m/s). Using in situ high speed imaging, the formation of the saw-tooth chip morphology is found to be due to crack initiation at the free surface. However, as the cutting speed (and strain rate) increases, the formation of the discontinuous, particle-type chip morphology is found to be due to crack initiation at the tool tip. In addition, the influences of tool rake angle, particle size, and particle volume fracture are investigated and found to have little effect on the chip morphology and chip formation mechanism.

Experimental Analysis of Ti6Al4V Orthogonal Cutting

2015 ◽  
Vol 665 ◽  
pp. 17-20 ◽  
Author(s):  
Apostolos Korlos ◽  
Orestis Friderikos ◽  
Dimitrios Sagris ◽  
Constantine David ◽  
Gabriel Mansour
Keyword(s):  
Formation Mechanism ◽  
Chip Formation ◽  
Orthogonal Cutting ◽  
Chip Morphology ◽  
Serrated Chip ◽  
Wide Range ◽  
Chip Formation Mechanism ◽  
Serrated Chip Formation ◽  
Chip Geometry ◽  
Cutting Speeds

The chip formation mechanism in orthogonal cutting is a phenomenon that attracts the attention of many researchers. This paper investigates experimentally the orthogonal cutting of Ti6Al4V at different cutting conditions aiming at the understanding of the chip formation mechanism. Serrated chip formation is obtained during orthogonal cutting of Ti6Al4V in a wide range of cutting speeds. The results are analyzed in order to extract useful indices relevant to chip geometry, as the adiabatic zone angle and other dimensions that describe the serrated chip. The cutting forces and the acoustic emission are measured. Finally, by the aid of 3D Computed Tomography (CT) the chip morphology is analyzed to better understand the segmentation process.

Study of Chip Morphology and Chip Formation Mechanism During Machining of Magnesium-Based Metal Matrix Composites

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Brian Davis ◽  
David Dabrow ◽  
Licheng Ju ◽  
Anhai Li ◽  
Chengying Xu ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Formation Mechanism ◽  
Chip Formation ◽  
Metal Matrix ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Matrix Composites ◽  
Particle Type ◽  
Chip Formation Mechanism ◽  
Cutting Speeds

Magnesium (Mg) and its alloys are among the lightest metallic structural materials, making them very attractive for use in the aerospace and automotive industries. Recently, Mg has been used in metal matrix composites (MMCs), demonstrating significant improvements in mechanical performance. However, the machinability of Mg-based MMCs is still largely elusive. In this study, Mg-based MMCs are machined using a wide range of cutting speeds in order to elucidate both the chip morphology and chip formation mechanism. Cutting speed is found to have the most significant influence on both the chip morphology and chip formation mechanism, with the propensity of discontinuous, particle-type chip formation increasing as the cutting speed increases. Saw-tooth chips are found to be the primary chip morphology at low cutting speeds (lower than 0.5 m/s), while discontinuous, particle-type chips prevail at high cutting speeds (higher than 1.0 m/s). Using in situ high-speed imaging, the formation of the saw-tooth chip morphology is found to be due to crack initiation at the free surface. However, as the cutting speed (and strain rate) increases, the formation of the discontinuous, particle-type chip morphology is found to be due to crack initiation at the tool tip. In addition, the influences of tool rake angle, particle size, and particle volume fracture are investigated and found to have little effect on the chip morphology and chip formation mechanism.

Quick Stop Device to Analyze the Chip Formation Mechanisms in Face Grinding

2016 ◽  
Vol 1140 ◽  
pp. 221-227 ◽  
Author(s):  
Tim Göttsching ◽  
Andi Wippermann ◽  
Thilo Grove
Keyword(s):  
Detailed Analysis ◽  
Contact Zone ◽  
Chip Formation ◽  
Suitable Method ◽  
Formation Mechanisms ◽  
Grinding Process ◽  
New Device ◽  
Advantages And Disadvantages ◽  
Face Grinding ◽  
Cutting Speeds

The chip formation mechanisms during grinding are not yet fully understood. The abrupt interruption of the grinding process with a quick stop device is a suitable method to analyze the chip formation mechanisms during grinding. However, there is no device available that enables a reproducible interruption at cutting speeds above vc = 5 m/s. Therefore a new method for the interruption of face grinding processes in order to analyze the chip formation mechanisms is presented in this paper. A quick stop device is designed and constructed based on the advantages and disadvantages of former approaches of other researchers. Grinding experiments with different rotational speeds confirm the potential of this new device. Interruptions of the grinding process at cutting speeds of vc = 5 m/s, 15 m/s, 25 m/s and 35 m/s are successfully accomplished. A detailed analysis of the contact zone with the help of SEM pictures impressively shows the interaction of hundreds of cutting edges along the contact zone.

ONE CHEMISTRY - TWO MEANINGS. SCIENCE AND EDUCATION: COMPARATIVE ANALYSIS OF THE ROLES, PRESENTATION AND APPLICATIONS

2019 ◽  
Author(s):  
Todar Lakhvich ◽  
Keyword(s):  
Comparative Analysis ◽  
Chemistry Education ◽  
Theoretical Study ◽  
Cultural Aspects ◽  
Science Philosophy ◽  
Science And Education ◽  
Made In

The comparative analysis of different meanings of Chemistry is carried out, taking in account philosophical, didactic, psychological and socio-cultural aspects. The issue is discussed in terms of the concurrent existence of two different subsystems referred both to Science and Education which can be found in presentations of chemistry knowledge. The study overviews researcher’s findings made in the field of Science Philosophy and Chemistry Didactics. Theoretical study based on profound concepts from Science and Chemistry philosophy as well on few empiric researches carried out by researcher in the field of Chemistry Didactics. Keywords: beautility, chemical object, chemistry education, modelling in science, visualization-based teaching.

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