Ductile Regime Single Point Diamond Turning of Quartz Resulting in an Improved and Damage-Free Surface

Abstract

& Quartz (fused silica) is one of the advanced engineered ceramic materials designed to operate in extreme environments. The mechanics of material removal in glass (Quartz) can be classified into two categories; brittle fracture and ductile plastic deformation. Good optical quality surfaces can be achieved by removing the material in a ductile manner. The strength, hardness and fracture toughness of the workpiece material are the governing factors that control the extent of brittle fracture. The main goal of the subject research is to improve the surface quality of Quartz to be used as an optic device (mirrors and windows) via single point diamond turning (SPDT). Sub-surface damage analysis was carried out on the machined sample using Scanning Acoustic Microscopy (SAcM). Surface roughness (R a ) values of less than 45 nm without sub surface damage were obtained. Tool wear was also investigated.

Experimental Investigation on Cutting Characteristics in Nanometric Plunge-Cutting of BK7 and Fused Silica Glasses

“…When the compressive stress exceeds the fracture limit, cracks and brittle fracture tend to arise and propagate. Ravindra and Patten [ 12 ] revealed that sufficient compressive stress would cause a ductile mode behavior, in which the material was removed by plastic deformation instead of brittle fracture. This micro-scale phenomenon exhibited strong relation to High Pressure Phase Transformation (HPPT) of the work material [ 12 , 23 , 24 , 25 ].…”

“…Blake and Scattergood [ 11 ] studied the CUCT for single crystals of germanium and silicon machining by using the diamond-turning lathe, and proposed several optimal cutting parameters for the ductile cutting, such as CUCT, tool geometries, and cutting speed. Ravindra and Patten [ 12 ] investigated the ductile regime of fused silica via single point diamond turning and found that the strength, hardness and fracture toughness of workpiece material played as the key factors that significantly affected the extent of brittle fracture. Zhou et al [ 13 ] investigated the brittle-ductile transition issue with diamond cutting of silicon from the viewpoint of material response and tool geometry.…”

Experimental Verification of Statistically Optimized Parameters for Low-Pressure Cold Spray Coating of Titanium

“…Silicon carbide (SiC), due to its extreme hardness and high wear resistance [4], is one of such powders for coating titanium alloy in order to confer higher hardness and wear resistance on it. a constitutive equation to solve the continuity, momentum, and energy equations governing the flow of fluid inside the de Lava nozzle used in the LPCS system; (2) Computational fluid dynamics (CFD) analysis of the flow through the nozzle to determine the input temperature that will yield the computed velocity at the exit of the nozzle; and (3) verification of the mathematical model by comparing the properties of coatings deposited using the CFD-optimized parameters and some non-optimized parameters.…”

Experimental work on micro laser-assisted diamond turning of silicon (111)

“…In order to develop a suitable process, ductile regime machining, considered to be one of the acceptable precision machining techniques, has been continuously studied over the last two decades [4][5][6][7][8][9][10][11][12]. In these researches, it has been demonstrated that ductile regime machining of semiconductor and ceramic materials is possible due to the high-pressure phase transformation (HPPT) occurring in the material caused by the high compressive and shear stresses induced by the single point diamond tool tip [13][14][15][16][17][18][19]. To further augment the ductile response of these materials, traditional SPDT is coupled with the micro laser assisted machining (-LAM) technique [1,2,[20][21][22].…”