Experimental Investigation of Thermo-Mechanical Characteristics in Laser-Assisted Machining of Silicon Nitride Ceramics

2000 ◽  
Vol 123 (4) ◽  
pp. 639-646 ◽  
Author(s):  
S. Lei ◽  
Y. C. Shin ◽  
F. P. Incropera
Keyword(s):  
Silicon Nitride ◽  
Tool Wear ◽  
Material Removal ◽  
Mechanical Characteristics ◽  
Surface Damage ◽  
Workpiece Temperature ◽  
Laser Assisted Machining ◽  
Nitride Ceramics ◽  
On Line ◽  
Extent Of Damage

Laser-assisted machining (LAM) of silicon nitride Si3N4 is evaluated for its potential to become an economically viable process in fabricating precision ceramic parts. On-line measurements of cutting force and workpiece temperature are performed, and tool wear and surface integrity are examined. Tool wear characteristics are determined as a function of workpiece temperature, which is measured on-line using a laser pyrometer. Tool wear/failure mechanisms are characterized using optical microscopy, while application of scanning electron microscopy to heated and machined surfaces, as well as to chips, is used to infer material removal mechanisms and the extent of damage caused by LAM. The sub-surface damage of parts produced by LAM is compared with that of typical ground parts.

Experimental Investigation of Thermo-Mechanical Characteristics in Laser-Assisted Machining of Silicon Nitride Ceramics

1999 ◽  
Author(s):  
Shuting Lei ◽  
Yung C. Shin ◽  
Frank P. Incropera
Keyword(s):  
Silicon Nitride ◽  
Tool Wear ◽  
Material Removal ◽  
Mechanical Characteristics ◽  
Surface Damage ◽  
Workpiece Temperature ◽  
Laser Assisted Machining ◽  
Nitride Ceramics ◽  
On Line ◽  
Extent Of Damage

Abstract Laser-assisted machining (LAM) of silicon nitride (Si3N4) is evaluated for its potential to become an economically viable process in fabricating precision ceramic parts. On-line measurements of cutting force and workpiece temperature are performed, and tool wear and surface integrity are examined. Tool wear characteristics are determined as a function of workpiece temperature, which is measured on-line using a laser pyrometer. Tool wear/failure mechanisms are characterized using optical microscopy, while application of scanning electron microscopy to heated and machined surfaces, as well as to chips, is used to infer material removal mechanisms and the extent of damage caused by LAM. The sub-surface damage of parts produced by LAM is compared with that of typical ground parts.

scholarly journals Microstructure of Silicon Nitride Ceramics and Morphology of Surface Damage Induced by Round Indenter

1994 ◽  
Vol 102 (1184) ◽  
pp. 350-354
Author(s):  
Yasuo UCHIYAMA ◽  
Kyozo SAHARA ◽  
Huiming CHENG ◽  
Kazuo KOBAYASHI ◽  
Sigetaka WADA ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Surface Damage ◽  
Nitride Ceramics ◽  
Morphology Of Surface

Laser Assisted Turning of Sintered Silicon Nitride

2010 ◽  
Vol 458 ◽  
pp. 113-118 ◽  
Author(s):  
Xue Feng Wu ◽  
Hong Zhi Zhang ◽  
Yang Wang
Keyword(s):  
Heat Transfer ◽  
Silicon Nitride ◽  
Tool Wear ◽  
Material Removal ◽  
Cutting Parameters ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Machined Surface ◽  
Laser Assisted Turning ◽  
Sintered Silicon

Laser assisted turning is an effective method machining difficult-to-machine materials such as ceramics, which uses a high power laser to focally heat a workpiece prior to material removal with a traditional cutting tool. A transient, three-dimensional heat transfer model was developed for laser assisted turning of silicon nitride using Finite Element Method to understand the thermal process of laser heating and to optimize the operating parameters. A laser assisted turning experiment system was set up to investigate the thermal conditions and cutting process of laser assisted turning of sintered silicon nitride and the experiments were conducted on the system using selected parameters. Effects of cutting parameters on cutting forces and specific cutting energy were investigated. Forces on the chip and SEM micrographs of chip morphology were studied to discuss the material removal mechanism of laser assisted turning of silicon nitride. Tool wear, surface roughness of the machined surface and the quality of subsurface were investigated. The results showed that the heat transfer model could be used to optimize the cutting parameters and laser assisted turning method could increase the machining efficiency while maintaining machining quality and reasonable levels of tool wear. A method of optimizing LAM based on the thermal model was presented.

Laser-Assisted Machining of a Fiber Reinforced Metal Matrix Composite

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Chinmaya R. Dandekar ◽  
Yung C. Shin
Keyword(s):  
Tool Wear ◽  
Metal Matrix ◽  
Material Removal ◽  
Volume Fraction ◽  
Cutting Speed ◽  
Subsurface Damage ◽  
Matrix Composites ◽  
Specific Cutting Energy ◽  
Laser Assisted Machining ◽  
Cutting Energy

Metal matrix composites, due to their excellent properties of high specific strength, fracture resistance, and corrosion resistance, are highly sought after over their nonferrous alloys, but these materials also present difficulty in machining. Excessive tool wear and high tooling costs of diamond tools make the cost associated with machining of these composites very high. This paper is concerned with the machining of high volume fraction long-fiber metal matrix composites (MMCs), which has seldom been studied. The composite material considered for this study is an Al–2% Cu aluminum matrix composite reinforced with 62% by volume fraction alumina fibers (Al–2% Cu/Al2O3). Laser-assisted machining (LAM) is utilized to improve the tool life and the material removal rate while minimizing the subsurface damage. The effectiveness of the laser-assisted machining process is studied by measuring the cutting forces, specific cutting energy, surface roughness, subsurface damage, and tool wear under various material removal temperatures. A multiphase finite element model is developed in ABAQUS/STANDARD to assist in the selection of cutting parameters such as tool rake angle, cutting speed, and material removal temperature. The multiphase model is also successful in predicting the damage depth on machining. The optimum material removal temperature is established as 300°C at a cutting speed of 30 m/min. LAM provides a 65% reduction in the surface roughness, specific cutting energy, tool wear rate, and minimum subsurface damage over conventional machining using the same cutting conditions.

Laser-Assisted Machining of a Fiber Reinforced Metal Matrix Composite

2009 ◽  
Author(s):  
Chinmaya R. Dandekar ◽  
Yung C. Shin
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Metal Matrix ◽  
Material Removal ◽  
Volume Fraction ◽  
Cutting Speed ◽  
Surface Damage ◽  
Specific Cutting Energy ◽  
Cutting Energy ◽  
Multi Phase

Metal matrix composites due to their excellent properties of high specific strength, fracture resistance and corrosion resistance are highly sought after over their non-ferrous alloys, but these materials also present difficulty in machining. Excessive tool wear and high tooling costs of diamond tools makes the cost associated with machining of these composites very high. This paper is concerned with machining of high volume fraction long-fiber MMC’s, which has seldom been studied. The composite material considered for this study is an Al-2%Cu aluminum matrix composite reinforced with 62% by volume fraction alumina fibers (Al-2%Cu/Al2O3). Laser-machining is utilized to improve the tool life and the material removal rate while minimizing the sub-surface damage. The effectiveness of the laser-assisted machining process is studied by measuring the cutting forces, specific cutting energy, surface roughness, sub-surface damage and tool wear under various material removal temperatures. A multi-phase finite element model is developed in ABAQUS/Standard to identify and assist in selection of cutting parameters such as; tool rake angle, cutting speed and material removal temperature. The multi-phase model is also successful in predicting the damage depth on machining. The optimum material removal temperature is established as 300°C at a cutting speed of 30 m/min. LAM provides a 65% reduction in the surface roughness, specific cutting energy, the tool wear rate and minimum sub-surface damage over conventional machining using the same cutting conditions.

Transient Thermal Response of a Rotating Cylindrical Silicon Nitride Workpiece Subjected to a Translating Laser Heat Source, Part I: Comparison of Surface Temperature Measurements With Theoretical Results

1998 ◽  
Vol 120 (4) ◽  
pp. 899-906 ◽  
Author(s):  
J. C. Rozzi ◽  
F. E. Pfefferkorn ◽  
F. P. Incropera ◽  
Y. C. Shin
Keyword(s):  
Silicon Nitride ◽  
Surface Temperature ◽  
Material Removal ◽  
Thermal Response ◽  
Thermal Conditions ◽  
Intense Laser ◽  
Laser Source ◽  
Beam Diameter ◽  
Laser Assisted Machining ◽  
Translational Speed

Laser-assisted machining (LAM), in which the material is locally heated by an intense laser source prior to material removal, provides an alternative machining process with the potential to yield higher material removal rates, as well as improved control of workpiece properties and geometry, for difficult-to-machine materials such as structural ceramics. To assess the feasibility of the LAM process and to obtain an improved understanding of governing physical phenomena, a laser assisted machining facility was developed and used to experimentally investigate the thermal response of a rotating silicon nitride workpiece heated by a translating CO2 laser. Using a focused laser pyrometer, surface temperature history measurements were made to determine the effect of rotational and translational speed, as well as the laser beam diameter and power, on thermal conditions. The experimental results are in good agreement with predictions based on a transient three-dimensional numerical simulation of the heating process. With increasing workpiece rotational speed, temperatures in proximity to the laser spot decrease, while those at circumferential locations further removed from the laser increase. Near-laser temperatures decrease with increasing beam diameter, while energy deposition by the laser and, correspondingly, workpiece surface temperatures increase with decreasing laser translational speed and increasing laser power, In a companion paper (Rozzi et al., 1998), the detailed numerical model is used to further elucidate thermal conditions associated with laser heating and to assess the merit of a simple, analytical model which is better suited for online process control.

Laser-Assisted Machining of Magnesia-Partially-Stabilized Zirconia

2004 ◽  
Vol 126 (1) ◽  
pp. 42-51 ◽  
Author(s):  
Frank E. Pfefferkorn ◽  
Yung C. Shin ◽  
Yinggang Tian ◽  
Frank P. Incropera
Keyword(s):  
Tool Wear ◽  
Material Removal ◽  
Cutting Temperature ◽  
Ductile Material ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
Material Removal Mechanisms ◽  
Laser Assisted Machining ◽  
Cutting Energy ◽  
Removal Mechanisms

Laser-assisted machining (LAM) of magnesia-partially-stabilized zirconia (PSZ) is investigated to determine the effect of heating on machinability, as determined by tool wear, cutting energy, surface integrity, and material removal mechanisms. It is found that PSZ can be successfully machined with a polycrystalline cubic boron nitride tool and that tool life increases with material removal temperature up to a maximum of 121 minutes. The benefit of laser-assistance in material removal is also demonstrated by the 2.5 fold decrease in the specific cutting energy with increased temperature. It is shown surface roughness varies significantly with tool wear with little dependence on cutting temperature unlike in LAM of other ceramics. Evidence of mixed brittle and ductile material removal mechanisms is presented, and the optimum condition within the test matrix is established.

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