Drilling of glass fibre reinforced plastic (GFRP) composite is different from metallic materials due to its mechanical properties. The drilling of this material may generate delamination of drilled holes on workpiece. The purpose of this paper is to investigate the influence of the cutting parameters, such as cutting speed and feed rate, point angle of drill and material thickness on delaminati...

Drilling engineering is a high input and risk underground project, which needs the real-time down-hole diagnosis and forecast technique. Drilling string vibration signals contain full and complex vibration waves, which contains the vibration of the drilling string by itself, the vibration stimulated by the interaction of bit and the formation, the vibration induced by colliding between drill st...

Bone drilling is a major part of modern orthopaedic surgery which involves the internal fixation of fractured bones. The investigation of bone drilling described in this paper demonstrates the contribution of automation technology towards the study of bone strength. The aim of this preliminary investigation is to establish a relationship between bone drilling forces and measurements of bone min...

Oil and gas drilling operations use drilling fluids (mud) to lubricate the drill bit and stem, transport formation cuttings to the surface, and seal off porous geologic formations. Following completion of the well, waste drilling fluid is often applied to cropland. We studied potential changes in soil compaction as indicated by cone penetration resistance, pH, electrical conductivity (EC(e)), s...

today’s energy reauiraments have produced an increase in drilling activities all around the world. among this situation is the fact that all the operators are trying to minimize cost without reduction in quality. so, they are looking for new types of contracts between all drilling companies, contractors and suppliers until that with make agreement between them have successful operations. in thi...

Solids control equipment at the rig site is used to remove rock cuttings or low-gravity solids (LGS) from drilling fluids to allow the fluid to return to the active system in a re-usable condition. Typical equipment, such as shakers and centrifuges, remove LGS particles greater than 5-7 microns. Build up of finer solids in the fluid can create problems for efficient drilling such as drillpipe s...

OBJECTIVE To assess if the screw design (self-drilling/self-tapping) and the pilot hole tapping could affect the insertion torque and screw pullout strength of the screw used in anterior fixation of the cervical spine. METHODS Forty self-tapping screws and 20 self-drilling screws were inserted into 10 models of artificial bone and 10 cervical vertebrae of sheep. The studied parameters were th...

Rotary drilling belongs to the key methods of rock separation not only in mining, but also in wider areas of geotechnologies 1, 2 . The most efficient separation of rocks is in so-called volume area which can be achieved with the correct choice of work tool and work mode while taking into account the geomechanical properties of rock separation. Theoretical research of rock separation by rotary ...

Multiplicity of the effective factors in drilling reflects the complexity of the interaction between rock mass and drilling bit, which is followed by the dependence of parameters and non-linear relationships between them. Rock mass or, in other words, the formation intended for drilling, as the drilling environment, plays a very essential role in the drilling speed, depreciation of drilling bit...

The treatment of osteochondritis dissecans after Legg-Calvé-Perthes' disease has not been clearly determined. It may be either by simple observation or surgical removal of the osteochondral fragment. We studied the evolution of the lesion in 13 children and reviewed 92 hips reported in the literature. In our patients ten showed a tendency towards spontaneous healing, one required drilling + gra...