In the oil industry, the measurement-while-drilling (MWD) systems are usually used to provide the real-time position and orientation of the bottom hole assembly (BHA) during drilling. However, the present MWD systems based on magnetic surveying technology can barely ensure good performance because of magnetic interference phenomena. In this paper, a MWD surveying system based on a fiber optic g...

Conventional drilling of rock, in most mining applications, uses the mechanical impact of a metal tool to create the advancing hole. This technique, which has gradually increased in power and thus penetration rate has, however, certain inherent disadvantages. These range from the overall weight of the equipment which must be located at the free face of the hole to the maintenance of alignment o...

Technological advances have facilitated many developments in the MEMS, electrical, medical and aerospace industries in recent years. As the devices commonly found in these industries have become smaller, so the requirements for high-precision machining techniques have become ever more pressing. Nowadays, micro-machining processes are playing an important role in satisfying these requirements. A...

[1] In Deep Sea Drilling Program (DSDP) Hole 417D in the western central North Atlantic, dips of pillow margins measured in the upper and lower part of basement correlate with tilts predicted from paleomagnetic inclinations in the corresponding parts of the hole. A 40 westward dip of the seafloor around 417Dmatches the tilt predicted from inclinations and pillow margin dips in the uppermost lav...

An optical system based on the confocal principle has been developed for real-time precision measurements of the depth of micro-holes during the laser drilling process. The capability of the measuring system is theoretically predicted by the Gaussian lens formula and experimentally validated to achieve a sensitivity of 0.5 μm. A nanosecond laser system was used to drill holes, and the hole dept...

Microdischarges in flexible copper-polyimide structures with hole diameters of 200 mm have been used as stencil masks to pattern bare silicon in CF4/Ar chemistry. The discharges were operated at 20 Torr using the substrate as the cathode, achieving etch rates greater than 7 mm/min. Optical emission spectroscopy provides evidence of excited fluorine atoms. The etch profiles show a peculiar shape...

The fracture and crack growth of mechanical structures is a usual phenomenon which is due to the application of tensile, cyclic loading or thermal stresses on the structure. So introducing of methods to prevent the crack growth is useful. Afterward, one of the repairing methods of crack growth, consisting to make a hole in the crack tip to elimi-nate the sharp corners, was explained. This metho...

Laser micromachining of dielectrics and metals is a versatile fabrication and repair tool for applications in micro-fluidics, microelectronics and MEMS. Issues such as ablation threshold, ablation rate, incubation of damage at subthreshold fluences, edge resolution, debris creation and residual substrate damage are all important in determining the suitability of this technique for these applica...

Drilling operations have an important role in manufacturing industries and the application range is about 33% among machining methods. In drilling processes, hole quality affected by workpiece material, parameters, drill diameter, bit features. this study, surface of wear were investigated experimentally when AISI 1040 steel Al7075 aluminum workpieces with twist drills. Three different types bi...