Hybrid CO2 Laser/Waterjet Machining of Polycrystalline Diamond Substrate: Material Separation Through Transformation Induced Controlled Fracture

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Dinesh Kalyanasundaram ◽  
Andrea Schmidt ◽  
Pal Molian ◽  
Pranav Shrotriya
Keyword(s):  
Co2 Laser ◽  
Polycrystalline Diamond ◽  
Substrate Material ◽  
Stress Fields ◽  
Separation Mechanism ◽  
Raman Spectrometry ◽  
Waterjet Machining ◽  
Machining System ◽  
Material Separation ◽  
Controlled Fracture

This paper presents a combined experimental and computational investigation of a novel material separation mechanism in polycrystalline diamond (PCD) substrates. A hybrid CO2 laser/waterjet (CO2-LWJ) machining system that combines a CO2 laser for localized heating and an abrasive-free waterjet to rapidly quench the heated area is utilized for cutting experiments on PCD substrates. Scanning electron microscopy (SEM) and micro-Raman spectrometry characterization performed on the cut surfaces show that cut surfaces were divided into two zones—a thin transformed zone near the top where the PCD grains have transformed to graphite and diamond-like carbon; and a fracture zone with the same composition as-received substrate. The experimental results indicate that the PCD substrates were cut through a “score and snap” mechanism—laser heating leads to localized damage and phase transformation of surface layers; and subsequently, stress fields developed due to constrained expansion of transformed material and waterjet quenching act on the laser made “score” to propagate crack through the thickness. Analytical solutions for thermal diffusion and force equilibrium are used to determine the temperature and stress fields in the PCD substrate during CO2-LWJ cutting. Fracture mechanics analysis of crack propagation is performed to demonstrate the feasibility of the “score and snap” mechanism for cutting of PCD substrates.

Bias Controlled Hot Filament Chemical Vapor Deposition of Diamond Thin Film on Various Substrates

1989 ◽  
Vol 162 ◽  
Author(s):  
Y. H. Lee ◽  
G.-H. Ma ◽  
K. J. Bachmann ◽  
J. T. Glass
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Lattice Parameter ◽  
Substrate Material ◽  
Diamond Growth ◽  
Interfacial Layers ◽  
Defect Densities

ABSTRACTThe growth of diamond films on Si(001), polycrystalline Ni, Mo, Ta, and W substrates by biased controlled chemical vapor deposition is discussed. Biasing effects were examined using the Si(001) substrates. The film quality as judged by Raman spectroscopy and scanning electron microscopy depended strongly on the biasing conditions. Under low current reverse bias conditions, highly faceted cubooctahedral polycrystalline diamond growth exhibiting a single sharp Raman line at 1332 cm-1 was obtained. Transmission electron microscopy indicated that these films contained relatively low defect densities and no significant interfacial layers. Biasing into high current conditions which created a plasma resulted in multiply twinned, microcrystalline growth incorporating sp2 bonded carbon into the diamond film. Such films were found to contain very high defect densities and a relatively thick interfacial layer. An investigation of the effects of substrate material was also conducted. Films grown on Si, Ni and W exhibited the best quality. The relationship between this quality and substrate properties such as surface energy and lattice parameter is discussed.

Cutting and marking machining system using a 3-kW CO2 laser

1983 ◽  
Author(s):  
S. Fujiwara ◽  
S. Ikuta ◽  
T. Takahashi ◽  
Y. Kado ◽  
Y. Matsumiya
Keyword(s):  
Co2 Laser ◽  
Machining System

Design of Exotic Materials Machining System

2013 ◽  
Vol 633 ◽  
pp. 36-46 ◽  
Author(s):  
John Mo ◽  
Song Lin Ding ◽  
Andrew Mackie ◽  
Milan Brandt ◽  
Shou Jin Sun ◽  
...  
Keyword(s):  
Electrical Discharge Machining ◽  
Cubic Boron Nitride ◽  
Polycrystalline Diamond ◽  
Gain Scheduling ◽  
Control System Design ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Machining System ◽  
Design Requirements ◽  
Fiber Reinforced Plastics

New exotic materials such as titanium alloys and carbon fiber reinforced plastics require strong hard cutters made of cubic boron nitride or polycrystalline diamond. However, the traditional mechanical diamond grinding process is slow and causes damage to the workpiece. This chapter examines the design requirements of an electrical discharge machining system that can be used to machine polycrystalline diamond tipped carbide drills. A preliminary theoretical model is described but the system complexity requires a gain scheduling approach to the control system design.

Characteristics of Abrasive Waterjet Generated Surfaces and Effects of Cutting Parameters and Structure Vibration

1995 ◽  
Vol 117 (4) ◽  
pp. 516-525 ◽  
Author(s):  
J. Chao ◽  
G. Zhou ◽  
M. C. Leu ◽  
E. Geskin
Keyword(s):  
Three Dimensional ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Abrasive Waterjet ◽  
Depth Of Cut ◽  
Height Distribution ◽  
Waterjet Machining ◽  
Machining System ◽  
Structure Vibration ◽  
Abrasive Size

We use three-dimensional surface topography analysis for evaluating waterjet generated surfaces. The waterjet generated surface is separated into smooth and striation zones, where striation influence is negligible in the smooth zone. It is found that the smooth zone has a random, moderately isotropic texture, with the height distribution nearly Gaussian. The effects of cutting speed, depth of cut, and abrasive size on the surface roughness are studied for the smooth zone and striation zone separately. This provides useful information for controlling process parameters to obtain smooth finished surfaces. Spectral analysis is used to investigate the surface striation and machine structure vibration. It is found that forced vibration of the mechanical structure strongly influences striations generated in the waterjet machining system.

Waterjet Machining and Peening of Metals

1999 ◽  
Vol 122 (1) ◽  
pp. 90-95 ◽  
Author(s):  
M. Ramulu ◽  
S. Kunaporn ◽  
D. Arola ◽  
M. Hashish ◽  
J. Hopkins
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Surface Integrity ◽  
Stress Fields ◽  
Abrasive Waterjet ◽  
Material Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Waterjet Machining ◽  
Measurement And Evaluation

An experimental study was conducted to determine the influence of high-pressure waterjet (WJ) peening and abrasive waterjet (AWJ) machining on the surface integrity and texture of metals. A combination of microstructure analysis, microhardness measurements, and profilometry were used in determining the depth of plastic deformation and surface texture that result from the material removal process. The measurement and evaluation of residual stress was conducted with X-ray diffraction. The residual stress fields resulting from treatment were analyzed to further distinguish the influence of material properties on the surface integrity. It was found that waterjet peening induces plastic deformation at the surface layer of metals as good as shot peening. The degree of plastic deformation and the state of material surface were found to be strongly dependent on the peening conditions applied. [S0094-9930(00)00801-5]

Deposition of a Silicon Carbide Reinforced Metal Matrix Composite (P25) Layer Using CO2 Laser

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Mum Wai Yip ◽  
Stuart Barnes ◽  
Ahmed Aly Diaa Mohmmed Sarhan
Keyword(s):  
Silicon Carbide ◽  
Co2 Laser ◽  
Matrix Material ◽  
Substrate Material ◽  
Material Surface ◽  
Feed System ◽  
Sic Particles ◽  
High Microhardness ◽  
Iron Based ◽  
High Precipitation

The objective of this research was to deposit a silicon carbide (SiC) reinforced layer of P25 (iron-based matrix material) on substrate material surface using CO2 laser. Two experiments using CO2 laser were carried out in this research. In the first experiment set, a gravity feed system was used with one powder feed containing different percentages of SiC particles and iron-based powder. In the second experiment set, preplaced powder was placed on substrate material surface. According to the experimental results, only few SiC particles were found in the clad matrix in the first experiment, and no SiC particles were found in the second experiment. A high microhardness value was noted in the SiC clad (above 1000 HV) in the first experiment compared to the second experiment with hardness values ranging from 200 HV to 700 HV. This was due to the high precipitation of carbide particles in the clad material during the first experiment. A comparison of the two different experiments signifies that the first one was the best because a more uniform layer with less porosity was produced.

scholarly journals Obtaining a Relationship Between Process Parameters and Fracture Characteristics for Hybrid CO2 Laser∕Waterjet Machining of Ceramics

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Dinesh Kalyanasundaram ◽  
Pranav Shrotriya ◽  
Pal Molian
Keyword(s):  
Crack Length ◽  
Energy Release ◽  
Co2 Laser ◽  
Process Parameters ◽  
Fracture Behavior ◽  
Local Heating ◽  
Stress Fields ◽  
Empirical Parameter ◽  
Equilibrium Crack ◽  
Machining Of Ceramics

A combined experimental and analytical approach is undertaken to identify the relationship between process parameters and fracture behavior in the cutting of a 1mm thick alumina samples by a hybrid CO2 laser∕waterjet (LWJ) manufacturing process. In LWJ machining, a 200W power laser was used for local heating followed by waterjet quenching of the sample surface leading to thermal shock fracture in the heated zone. Experimental results indicate three characteristic fracture responses: scribing, controlled separation, and uncontrolled fracture. A Green’s function based approach is used to develop an analytical solution for temperatures and stress fields generated in the workpiece during laser heating and subsequent waterjet quenching along the machining path. Temperature distribution was experimentally measured using thermocouples and compared with analytical predictions in order to validate the model assumptions. Computed thermal stress fields are utilized to determine the stress intensity factor and energy release rate for different configurations of cracks that caused scribing or separation of the workpiece. Calculated crack driving forces are compared with fracture toughness and critical energy release rates to predict the equilibrium crack length for scribed samples and the process parameters associated with transition from scribing to separation. Both of these predictions are in good agreement with experimental observations. An empirical parameter is developed to identify the transition from controlled separation to uncontrolled cracking because the equilibrium crack length based analysis is unable to predict this transition. Finally, the analytical model and empirical parameter are utilized to create a map that relates the process parameters to the fracture behavior of alumina samples.

Flexural motion due to laser ablation: Influence of force location on the flexural motion

2004 ◽  
Vol 218 (12) ◽  
pp. 1411-1420 ◽  
Author(s):  
B S Yilbas ◽  
J Hyder
Keyword(s):  
Shear Stress ◽  
Laser Ablation ◽  
Maximum Shear Stress ◽  
Substrate Material ◽  
Thin Layers ◽  
Stress Fields ◽  
Pressure Force ◽  
Ablation Process ◽  
Maximum Displacement ◽  
Recoil Pressure

The flexural motion of a multilayer assembly subjected to laser ablation is studied. The assembly consists of thin layers of Inconel alloy (top and bottom layers) and a steel layer (intermediate layer). The assembly resembles a stainless steel sheet with both surfaces coated. The recoil pressure generated during the ablation process results in a loading pressure force acting normal to the assembly surface. The pressure force causes flexural motion in the assembly. In order to secure a sufficiently large flexural displacement, a cantilever arrangement of the assembly is considered. The recoil pressure and the resulting force are formulated and the flexural displacement as well as the resulting stress fields are computed. The influence of the pressure force location at the assembly surface on the flexural motion is examined. It is found that the time occurrence of maximum flexural displacement is the same for all the load locations and the maximum displacement occurs at the free end of the cantilever assembly. The magnitude of normal stresses and shear stress is less than the yielding limit of the substrate material. Moreover, the maximum shear stress is almost three times the maximum normal stress in the assembly.

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