Single Point Diamond Turning of CVD Coated Silicon Carbide

2006 ◽  
Author(s):  
Biswarup Bhattacharya ◽  
John A. Patten ◽  
Jerry Jacob
Keyword(s):  
Silicon Carbide ◽  
Single Point ◽  
Diamond Turning ◽  
Depth Of Cut ◽  
Critical Depth ◽  
Machined Surface ◽  
Brittle Transition ◽  
Ductile Regime Machining ◽  
Critical Depth Of Cut ◽  
Ductile To Brittle Transition

Scratching experiments, using diamond styli and single point diamond tools, were performed to simulate Single Point Diamond Turning (SPDT). The results of these experiments were used to determine if a ductile response is possible, and then to determine the critical depth of cut or penetration depth for the ductile to brittle transition (DBT). The depths of the scratches produced at different loads were measured and correlated to the ductile and brittle response of the material. The DBT depth for Chemically Vapor Deposited (CVD) coated Silicon Carbide (SiC) samples was determined. The analysis for the critical depth (DBT) did confirm the possibility for SPDT of CVD coated SiC in the ductile regime. These results were further used for SPDT of CVD SiC. Post experimental analysis of the machined surface did reveal a final surface roughness of 8–20nm, successfully demonstrating ductile regime machining of CVD coated SiC.

Study of Ductile-to-Brittle Transition in Single Grit Diamond Scribing of Silicon: Application to Wire Sawing of Silicon Wafers

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Hao Wu ◽  
Shreyes N. Melkote
Keyword(s):  
Hydrostatic Pressure ◽  
Silicon Wafers ◽  
Depth Of Cut ◽  
Critical Depth ◽  
External Hydrostatic Pressure ◽  
Tensile Stresses ◽  
Brittle Transition ◽  
Ductile Mode Cutting ◽  
Critical Depth Of Cut ◽  
Ductile To Brittle Transition

The ductile-to-brittle cutting mode transition in single grit diamond scribing of monocrystalline silicon is investigated in this paper. Specifically, the effects of scriber tip geometry, coefficient of friction, and external hydrostatic pressure on the critical depth of cut associated with ductile-to-brittle transition and crack generation are studied via an eXtended Finite Element Method (XFEM) based model, which is experimentally validated. Scribers with a large tip radius are shown to produce lower tensile stresses and a larger critical depth of cut compared with scribers with a sharp tip. Spherical tipped scribers are shown to generate only surface cracks, while sharp tipped scribers (conical, Berkovich and Vickers) are found to create large subsurface tensile stresses, which can lead to nucleation of subsurface median/lateral cracks. Lowering the friction coefficient tends to increase the critical depth of cut and hence the extent of ductile mode cutting. The results also show that larger critical depth of cut can be obtained under external hydrostatic pressure. This knowledge is expected to be useful in optimizing the design and application of the diamond coated wire employed in fixed abrasive diamond wire sawing of photovoltaic silicon wafers.

Chip Topography for Ductile-Regime Machining of Germanium

1994 ◽  
Vol 116 (2) ◽  
pp. 263-266 ◽  
Author(s):  
W. S. Blackley ◽  
R. O. Scattergood
Keyword(s):  
Diamond Turning ◽  
Cutting Depth ◽  
Machined Surface ◽  
Free Surfaces ◽  
Brittle Transition ◽  
Critical Cutting Depth ◽  
Independent Estimate ◽  
Ductile Regime Machining ◽  
Ductile To Brittle Transition ◽  
Insight Into

Ductile-regime response during the diamond turning of brittle germanium crystals is evident from the damage-free surfaces obtained. The nature of the ductile-regime processes cannot be determined by examination of the final machined surface itself. Machining chips were characterized using scanning electron microscopy. The chip topography provides insight into the ductile-to-brittle transition that occurs along the tool nose. A detailed examinaiton of the chips provides an independent estimate of the critical cutting depth for the transition.

scholarly journals Modeling and Experiment of the Critical Depth of Cut at the Ductile–Brittle Transition for a 4H-SiC Single Crystal

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 382 ◽  
Author(s):  
Peng Chai ◽  
Shujuan Li ◽  
Yan Li
Keyword(s):  
Single Crystal ◽  
Lateral Displacement ◽  
Tangential Force ◽  
Test System ◽  
Depth Of Cut ◽  
Critical Depth ◽  
Berkovich Indenter ◽  
Nose Radius ◽  
Brittle Transition ◽  
Critical Depth Of Cut

In this paper, a theoretical model of the critical depth of cut of nanoscratching on a 4H-SiC single crystal with a Berkovich indenter is proposed, and a series of scratch tests in a nanomechanical test system was performed. Through nanoindentation experimentation on fused quartz, the Berkovich indenter nose radius was indirectly confirmed using least squares. The range of critical depths of cut at the ductile–brittle transition was obtained by SEM observation, and the size of cracks was amplified with increasing scratching depth. The theoretical result of the critical depth of cut at the ductile–brittle transition for a 4H-SiC single crystal is 91.7 nm, which is close to the first obvious pop-in point of the relation curve between tangential force and lateral displacement. Repeated experimental results show good consistency and good agreement with other references.

Ultra-Precision Cutting of Brittle Materials with Ultrasonic Vibrated Diamond Tool

2006 ◽  
Vol 532-533 ◽  
pp. 169-172 ◽  
Author(s):  
Chun Xiang Ma ◽  
Eiji Shamoto ◽  
Li Ming Xu ◽  
Nan Liu ◽  
T. Moriwaki
Keyword(s):  
Diamond Tool ◽  
Brittle Materials ◽  
Optical Quality ◽  
Depth Of Cut ◽  
Critical Depth ◽  
Machined Surface ◽  
Ductile Cutting ◽  
Ultra Precision ◽  
Critical Depth Of Cut ◽  
Quality Surface

The influence of the ultrasonic vibrated diamond tool on the transition of ductile cutting to brittle cutting of the glasses is investigated by facing turning. It is understood that the critical depth of cut for the ductile cutting of the brittle materials is increased obviously by the ultrasonic vibrated diamond tool. The optical quality surface of the glasses is obtained, the surface roughness of which is less than0.03m. Finally, the relation between the roughness of machined surface and the cutting distance is studied experimentally.

Numerical Investigation of Two-Dimensional Thermally Assisted Ductile Regime Milling of Brittle Materials

2014 ◽  
Author(s):  
Jianfeng Ma ◽  
Xianchen Ge ◽  
Shuting Lei
Keyword(s):  
Chip Thickness ◽  
Rake Angle ◽  
Depth Of Cut ◽  
Critical Depth ◽  
Uncut Chip Thickness ◽  
Thermal Boundary Conditions ◽  
Orthogonal Machining ◽  
Preheating Temperature ◽  
Ductile Regime Machining ◽  
Critical Depth Of Cut

This study investigates the effects of different variables (preheating temperature, edge radius, and rake angle) on ductile regime milling of a bioceramic material known as nanohydroxyapatite (nano-HAP) using numerical simulation. AdvantEdge FEM Version 6.1 is used to conduct the simulation of 2D milling mimicked by orthogonal machining with varying uncut chip thickness. Thermal boundary conditions are specified to approximate laser preheating of the work material. Based on the pressure-based criterion for ductile regime machining, the dependence of critical depth of cut on cutting conditions is investigated using Tecplot 360. It is found that as uncut chip thickness decreases, the critical depth of cut decreases. In addition, the critical depth of cut increases as the negativity of rake angle and/or preheating temperature increase.

Machinability Investigation of Reaction-Bonded Silicon Carbide by Single-Point Diamond Turning

2008 ◽  
Vol 389-390 ◽  
pp. 151-156 ◽  
Author(s):  
Zhi Yu Zhang ◽  
Ji Wang Yan ◽  
Tsunemoto Kuriyagawa
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Large Scale ◽  
High Efficiency ◽  
Low Cost ◽  
Single Point ◽  
Diamond Turning ◽  
Machining Process ◽  
Depth Of Cut ◽  
Material Microstructure

Reaction-bonded silicon carbide (RB-SiC) is a recently developed ceramic material with many merits such as low manufacturing temperature, dense structure, high purity and low cost. In the present paper, the precision machinability of RB-SiC was studied by microindentation and single-point diamond turning (SPDT) tests. The influence of depth of cut and tool feed rate on surface roughness and cutting force was investigated. Results showed that there was no clear ductile-brittle transition in machining behavior. The material removal mechanism involves falling of the SiC grains and intergranular microfractures of the bonding silicon, which prevents from large-scale cleavage fractures. The minimum surface roughness depends on the initial material microstructure in terms of sizes of the SiC grains and micro pores. This work preliminarily indicates that SPDT can be used as a high-efficiency machining process for RB-SiC.

Improving the Surface Roughness of a CVD Coated Silicon Carbide Disk by Performing Ductile Regime Single Point Diamond Turning

2008 ◽  
Author(s):  
Deepak Ravindra ◽  
John Patten
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Surface Quality ◽  
Removal Rate ◽  
Single Point ◽  
Extreme Environments ◽  
High Hardness ◽  
Diamond Turning ◽  
Ductile Regime Machining

Silicon carbide (SiC) is one of the advanced engineered ceramics materials designed to operate in extreme environments. One of the main reasons for the choice of this material is due to its excellent electrical, mechanical and optical properties that benefit the semiconductor, MEMS and optoelectronic industry respectively. Manufacture of this material is extremely challenging due to its high hardness, brittle characteristics and poor machinability. Severe fracture can result when trying to machine SiC due to its low fracture toughness. However, from past experience it has been proven that ductile regime machining of silicon carbide is possible. The main goal of the subject research is to improve the surface quality of a chemically vapor deposited (CVD) polycrystalline SiC material to be used in an optics device such as a mirror. Besides improving the surface roughness of the material, the research also emphasized increasing the material removal rate (MRR) and minimizing the diamond tool wear. The surface quality was improved using a Single Point Diamond Turning (SPDT) machining operation from 1158nm to 88nm (Ra) and from 8.49μm to 0.53μm (Rz; peak-to-valley).

Analysis of the Swelling Effect in Single-Point Diamond Turning

2011 ◽  
Vol 314-316 ◽  
pp. 984-987
Author(s):  
Qing Liang Zhao ◽  
Jun Yun Chen ◽  
Jian Luo
Keyword(s):  
Surface Roughness ◽  
Material Property ◽  
Single Point ◽  
Diamond Turning ◽  
Surface Generation ◽  
Ductile Material ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Tool Mark ◽  
Material Swelling

The swelling effect is an important factor to affect surface generation in SPDT. Face cutting experiments are conducted for copper, aluminum alloy and electroless nickel phosphorus to analyze the swelling effect including the relationship between it and cutting parameters as well as effect of material property. How the material swelling affects surface roughness is also studied in this paper. The results indicate that the swelling effect is influenced by spindle speed and material property more remarkably when compared to feed rate and depth of cut. In addition, a softer and more ductile material will lead to a stronger material recovery, a lower swelling proportion, a lower tool mark height and a smoother machined surface. The result reveals that the swelling effect must be considered when predicting surface roughness in SPDT

A Study of Scratch Speed Effects on Ductile–Brittle Transition in Silicon

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Chirag Alreja ◽  
Sathyan Subbiah
Keyword(s):  
Crack Density ◽  
Diamond Turning ◽  
Depth Of Cut ◽  
Critical Depth ◽  
Scanning Electron Microscopy Morphology ◽  
Critical Depth Of Cut ◽  
P Type ◽  
Very High ◽  
Cutting Speeds ◽  
Comprehensive Study

A unique rotational double-taper scratching setup is used to study ductile brittle transitions in single crystal (100) p-type silicon using a conical diamond tool at room temperature and scratching speeds ranging between 0.1 m/s and 0.3 m/s. In such a setup, transition from brittle to ductile occurs twice in a single-tapered scratch, during tool entry and tool exit. A well-defined way to determine critical depth of cut via linear crack density per unit crack length is proposed. The scratches were studied using scanning electron microscopy (morphology) and white light interferometry (depth measurements). A comprehensive study of critical depth of cut, compiled from the literature together with data from this study, with scratching speeds from very low to high shows that critical depth of cut decreases from very low scratch speeds to medium scratch speeds and then increases again at very high scratch speeds. An inference from this study is that diamond turning should be conducted at higher cutting speeds than being undertaken today to make use of larger critical depths of cut.

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