Classical Drilling Research Articles

Experimental Investigation of Flow Drilling and Flow Tapping of Thin-Walled Square and Circular Hollow Sections

One of the most important problems of automotive engineering is joining metal sheets, thin-walled tubes or profiles simply, efficiently, and economically. After conventional drilling and tapping in thin-walled materials, the strength remains low due to the small number of teeth and the connection can be easily unfastened. For increasing the strength there are several solutions such as using welded nuts, tapped rivets and welding extra nuts. Since nut welding cannot be done on the inner surfaces, these solutions are inadequate for square and circular tubes. In this study, holes of various diameters were drilled on 1.5 mm thick AISI 304 stainless steel and EN AW-6060 square and circular profiles by flow drilling at various rotational speeds, and then flow tapping was applied to the holes. The same processes were repeated with conventional drilling method to compare bushing heights and clamping strengths of the parts as well as the hardness values and capillary crack formations around the holes. According to the results obtained, the strength in flow drilling and tapping increases by 50-55% compared to the classical drilling method. The reason for this is that as the hole diameter increases, the amount of material plastered and the number of threads required for screwing increases approximately 2.5-3 times. Capillary cracks, which are observed in holes drilled with the traditional method as the hole diameter increases, are not observed with this method and thus increasing the strength of the connection.

Determination of yield of fractional material bydestruction of martiteore by water jets depending on the direction of their cutting

Purpose. Highlight the main results of the experiments performed on the destruction of martite ores by the method of borehole hydraulic destruction by their layering. Since, as a result of the analysis of literary sources, it was established that some of the deposits of the Kryvyi Rihiron ore basin are suitable for hydro monitor excavation.Consideration of the method of introducing technologies for hydromechanization of mining operations in the conditions of the Kryvyi Rihiron ore basin is a topical issue. The methods. Using experimental installations conduct experiments on the destruction of layers of martite ores, gradually increasing the water pressure and determine the qualitative fractional yield of raw materials. Mathematical processing of the results obtained and the construction of dependencies based on experiments. Findings. Showing of the sequence of the experiment, the creation of summary tables with the results and the construction of illustrated graphs is the result of a study of determining the yield of fractional material during the destruction of ores by water jets. The originality. Experiments have shown that the yield of the ore fraction during their destruction using the hydro fracture method depends both on the water pressure and on the stratification of the ores. Ores that break down along the layer are more prone to overgrinding, and ores that break into a cross are less likely to. Therefore, the output of fractions during the destruction of layers of martite ores in some values can be controlled. Practical implementation. The development of floodingdeposits of rich iron ores by classical, unsuitable methods is accompanied by a large number of losses of ore raw materials or the impossibility of developing the deposit, because an alternative to the classical drilling and blasting method of destruction of a massif of rock is proposed technology of hydromechanization.The use of borehole hydraulic mining technology will allow the use of water flows from drainage wells or a sump for the safe, non-explosive destruction of the massif. This will increase the safety of mining operations, as well as reduce the seismic impact on the workings before the start of stope extraction.

The analysis of shaft sinking progress as a function of technical and organizational parameters

Abstract In underground mines, where the deposit is located at considerable depths, mining shafts are key excavations. The project of making the deposit available requires selection of appropriate shaft sinking technology adapted to geological and hydrological conditions and natural hazards. Shafts can be made using the classic drilling and blasting technique or mechanical cutting of the shaft face. Mechanical cutting requires the use of a mining machine, which together with machines for loading and hauling the output and protecting the side walls is a shaft complex. Drilling using mechanized shaft complexes allows for high efficiency and work safety. To improve the efficiency of drilling, it is particularly important to implement many processes in parallel. The article presents an analysis of the progress of shaft sinking with a mechanized complex as a function of technical and organizational parameters. The analysis concerned a new generation cutting shaft complex, developed for the needs of shaft sinking for one of the Polish hard coal mines. The calculations were carried out for a shaft with a maximum diameter of 9.5 m and a total depth of 830 m. The article briefly presents a new solution for the shaft complex. There are presented results of calculations of daily drilling progress and total time of shaft sinking for the developed working technology of this complex. The efficiency of the complex depends on many factors related to technical parameters of individual machines and devices forming the complex and organizational parameters, hence a multi-variant analysis was carried out.

Comparative Evaluation of Cell Viability Immediately After Osteotomy for Implants With Drills and Piezosurgery: Immunohistochemistry Analysis.

To evaluate the effect of reusing drills and piezosurgery tips during implant osteotomy on immediate bone cell viability through immunohistochemical analysis. Six male rabbits were divided into 2 groups and then divided into 5 subgroups-correspond to drills and tips used 10, 20, 30, 40, and 50 times, respectively. All animals received 10 osteotomies in each tibia, by use of the classic drilling procedure in one group (G1) and the piezosurgery device in the other group (G2). For immunohistochemical technique were utilized the osteoprotegerin, RANKL, osteocalcin, and caspase 3. Control procedures were performed by omitting the primary antibodies (negative control). Bone formation and resorption responses presented in more intense way during the piezosurgery. The expression of osteocalcin had become quite intense in piezosurgery groups, but with reduced immunostaining from the 30th osteotomy. The caspase 3 showed the viability of the osteoblast from the 20th osteotomy with piezosurgery and remained constant until the 50th. Piezosurgery provides greater osteoblastic cell viability than the system of conventional drilling. This study will provide data so that the authors can recycle the drills and tips for implant placement, thus enabling a better cell viability for osseointegration.

Regional hazard prediction of rock bursts using microseismic energy attenuation tomography in deep mining

Rock burst prediction is a worldwide challenge that we have long tried to overcome. This study tentatively proposed a method to regionally predict rock burst hazards using microseismic energy attenuation. To verify the feasibility of the proposal, first, the mechanism of microseismic energy propagation and attenuation in rock medium was explored, and dominant attenuation characteristics of microseismic waves were analyzed. Second, a spatial attenuation model of microseismic energy was established, and the average energy attenuation coefficient for each wave path was defined. A 3D seismic energy attenuation inversion algorithm was put forward, and the corresponding computation matrix was developed. Third, a continuous microseismic field investigation was carried out in a deep coal mine. Seismic energy attenuation coefficient was confirmed using the calibrated focus position and energy determination. Based on data discretization processing, energy attenuation inversion and tomography, potential rock burst hazard regions were strictly zoned in mining areas. Finally, regional prediction results obtained from the microseismic energy attenuation were compared with the direct measurement results obtained from the classical drilling dust method to verify the reliability of proposed approach. It turns out that rock burst hazard regions predicted by the microseismic energy attenuation agreed well with the objective hazardous situations. Seismic energy attenuation coefficient is a significant evaluation factor that directly mirrors the inelastic performance of rock medium. Energy attenuation coefficient threshold used for determining the rock burst hazard regions was 3.0 km−1. Reliability of the seismic energy attenuation inversion and tomography was closely related to the spatial distribution of microseisms in a localized region. The optimum spatial density of microseisms was 0.2 m−3. Regional rock burst prediction using microseismic energy attenuation is an effective approach for revealing potential hazardous regions in deep mining conditions. This approach improves the pertinence of geological hazard prevention and provides a beforehand reference for targeted hazard management.

Colliding jets provide depth control for water jetting in bone tissue

In orthopaedic surgery, water jet drilling provides several advantages over classic drilling with rigid drilling bits, such as the always sharp cut, absence of thermal damage and increased manoeuvrability. Previous research showed that the heterogeneity of bone tissue can cause variation in drilling depth whilst water jet drilling.To improve control over the drilling depth, a new method is tested consisting of two water jets that collide directly below the bone surface. The expected working principle is that after collision the jets will disintegrate, with the result of eliminating the destructive power of the coherent jets and leaving the bone tissue underneath the focal point intact. To assess the working principle of colliding water jets (CWJ), the influence of inhomogeneity of the bone tissue on the variation of the drilling depth and the impact of jet time (twj) on the drilling depth were compared to a single water jet (SWJ) with a similar power.98 holes were drilled in 14 submerged porcine tali with two conditions CWJ (impact angle of 30° and 90°) and SWJ. The water pressure was 70MPa for all conditions. The water jet diameter was 0.3 mm for CWJ and 0.4 mm for SWJ. twj was set at 1, 3, 5 and 8s. Drilling depth and hole diameter were measured using microCT scans. A non-parametric Levene's test was performed to assess a significant difference in variance between conditions SWJ and CWJ. A regression analysis was used to determine differences in influence of twj on the drilling depth. Hole diameter differences were assessed using a one way Anova. A significance level of p<0.05 was set.Condition CWJ significantly decreases the drilling depth variance caused by the heterogeneity of the bone when compared to SWJ. The mean depth for CWJ was 0.9 mm (SD 0.3 mm) versus 4.8 mm (SD 2.0) for SWJ. twj affects the drilling depth less for condition CWJ (p<0.01, R2=0.30) than for SWJ (p<0.01, R2=0.46). The impact angle (30° or 90°) of the CWJ does not influence the drilling depth nor the variation in depth. The diameters of the resulting holes in the direction of the jets is significantly larger for CWJ at 90° than for 30° or a single jet.This study shows that CWJ provides accurate depth control when water jet drilling in an inhomogeneous material such as bone. The maximum variance measured by using the 95% confidence interval is 0.6 mm opposed to 5.4 mm for SWJ. This variance is smaller than the accuracy required for bone debridement treatments (2–4 mm deep) or drilling pilot holes. This confirms that the use of CWJ is an inherently safe method that can be used to accurately drill in bones.

A simple solution for evaluation of lubricants anti-wear properties

The present paper describes a simple four balls testing device adapted for a classical drilling machine, using standard methodology meant to evaluate the lubricating properties of lubricants. The advantage of the method consists in the possibility of using any type of balls and a special device adapted to a common drilling machine. The evaluation of anti-wear lubricants properties can be done by comparing the contact scar dimension obtained experimentally, following the procedure described in EN ISO 20623:2003 international standard. The contact scar diameter is measured using an optic microscope equipped with a camera and specialized software, by comparing the scar with a known body dimension. Some experimental results obtained for the contact between four 12.7 mm bearing balls lubricated with grease are presented as well. The contact scar dimension-load dependencies are similar to those presented in literature and therefore validate the experimental setup.

Effect of CuO and ZnO nanofluids in xanthan gum on thermal, electrical and high pressure rheology of water-based drilling fluids

Nanofluids show potential use in applications related to upstream oil and gas industry to improve the performance of several processes such as exploration, drilling and completion, production and enhanced oil recovery operations. However, their applications to water-based drilling mud (WBM) needs attention to address efficient drilling in an High Pressure and High Temperature (HPHT) environment. In the present work, nanofluid-enhanced WBM (NWBM) are prepared using the nanofluids of CuO and ZnO (size ˂50nm) in a xanthan gum aqueous solution as a base fluid, and used as an additive in WBM. The nanofluids are prepared for nanoparticle concentrations of 0.1, 0.3 and 0.5wt% in base. The prepared nanofluids are added as an additive of 1% (by volume) to WBM. The enhancement in thermal and electrical properties of NWBH is studied. It is observed that NWBM show improved thermal and electrical properties by about 35% compared to WBM. An increased concentration of nanoparticles further enhances electrical and thermal properties of drilling fluids. The NWBM based on CuO nanofluid are observed to show improved thermal properties, and are more resistant to HPHT condition than ZnO-based NWBM. High pressure rheological studies are conducted on NWBM to understand the effect of nanofluids on the rheological properties at varying temperatures (25, 70, 90 and 110°C) and pressures (0.1MPa and 10MPa). The effect of pressure on the rheology of NWBM is more significant at higher temperatures, and indicates better rheological stability in case of NWBM. The most significant role that the nanofluids play is in stabilizing the viscosity at higher temperatures. The experimental data on flow curves obtained for various NWBM are fitted to the classical drilling fluid rheological models (Power Law model, Bingham Plastic model and Herschel–Bulkley model). The Herschel Bulkley model is observed to be the best fit-model for rheological behavior of NWBM and can be applied for efficient NWBM design.

Evaluation of Bone Heating, Drill Deformation, and Drill Roughness After Implant Osteotomy: Guided Surgery and Classic Drilling Procedure

This study evaluated and compared bone heating, drill deformation, and drill roughness after several implant osteotomies in the guided surgery technique and the classic drilling procedure. The tibias of 20 rabbits were used. The animals were divided into a guided surgery group (GG) and a control group (CG); subgroups were then designated (G0, G1, G2, G3, and G4, corresponding to drills used 0, 10, 20, 30 and 40 times, respectively). Each animal received 10 sequential osteotomies (5 in each tibia) with each technique. Thermal changes were quantified, drill roughness was measured, and the drills were subjected to scanning electron microscopy. Bone temperature generated by drilling was significantly higher in the GG than in the CG. Drill deformation in the GG and CG increased with drill use, and in the CG a significant difference between G0 and groups G3 and G4 was observed. In the GG, a significant difference between G0 and all other groups was found. For GG versus CG, a significant difference was found in the 40th osteotomy. Drill roughness in both groups was progressive in accordance with increased use, but there was no statistically significant difference between subgroups or between GG and CG overall. During preparation of implant osteotomies, the guided surgery technique generated a higher bone temperature and deformed drills more than the classic drilling procedure. The increase in tissue temperature was directly proportional to the number of times drills were used, but neither technique generated critical necrosis-inducing temperatures. Drill deformation was directly proportional to the number of times the drills were used. The roughness of the drills was directly proportional to the number of reuses in both groups but tended to be higher in the GG group.

Raman and IR reflection micro‐spectroscopic study of Er:YAG laser treated permanent and deciduous human teeth

Permanent and deciduous human teeth treated by a dental Er‐doped yttrium‐aluminium‐garnet pulse laser (λ = 2940 nm) as well as by classical drilling tools under conditions typical of the clinical practice were studied by ultraviolet Raman and Fourier transform infrared (FTIR) reflection microspectroscopy. Enamel was analyzed by both spectroscopic methods, whereas dentine was studied only by FTIR reflection because of the high level of photoluminescence continuum background even when a wavelength of 325 nm was used in inelastic light scattering experiments. The applied energy and pulse frequency of the dental laser varied between 200 and 500 mJ and between 10 and 30 Hz, respectively. The most important result is that after the laser treatment, the hydroxyapatite structure in both permanent and deciduous enamel is preserved: the apatite Ca‐P‐O framework remains intact, and the content of channel OH‐ groups is not changed within experimental uncertainties. The calcium‐phosphate framework of dentine also exhibits negligible laser‐induced changes. The only alterations in enamel induced by laser as well as by mechanical drilling are reduction of the amount of CO32‐ in apatite and changes in the protein conformation. The laser impact on the organic material and carbonate groups is strongest for laser power of 8 W; for powers of 4 or 5 W, the combination of higher pulse energy and lower pulse frequency has less impact than the combination of lower energy and higher frequency. No differences between deciduous and permanent teeth in their resistivity to laser irradiation with λ = 2940 nm were detected. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Guided Implant Surgery: What Is the Influence of This New Technique on Bone Cell Viability?

To evaluate the effect of implant osteotomy on immediate bone cell viability, comparing guided surgery for implant placement with the classic drilling procedure. For this study, 20 rabbits were used. The animals were divided into a guided surgery group (GG) and a control group (CG) and were then divided into 4 subgroups--subgroups 1, 2, 3, and 4--corresponding to drills used 10, 20, 30, and 40 times, respectively. All animals received 5 osteotomies in each tibia, by use of the classic drilling procedure in one tibia and guided surgery in the other tibia. The osteotomized areas were removed and processed immunohistochemically for detection of osteocalcin, receptor activator of nuclear factor κB ligand (RANKL), osteoprotegerin (OPG), and caspase 3. Immunohistochemical analysis showed that osteocalcin expression was initially higher in the CG and remained constant after drill reutilization. Although the expressions of RANKL and OPG were not statistically different for the GG and CG, the RANKL/OPG ratio tended to be higher for the GG. Moreover, caspase 3 expression was elevated in the GG, proportionally to the number of osteotomies, indicating an increase in the apoptosis index in the GG. The classic drilling procedure is more favorable to cell viability than guided surgery.

Noncontact Er:YAG Laser Ablation: Clinical Evaluation

The aim of this study is to evaluate the quality of laser ablation in comparison with the classical drilling preparation. For the experiment, the Er:YAG laser drilling machine was used. The system had a laser head, water cooler, and power supply with automatic control. Spot size of 300-350 microns was used for the preparation. Repetition rate of 1-4 Hz, and pulse energies of 100-400 mJ with water spray were chosen. Cavity shape in comparison with classical drill, time of preparation, and influence of cavity shape on filling materials retention in accordance with the U.S. Public Health Service System were used. The evaluation criteria for noncontact Er:YAG ablation were done. The cavity shape is irregular, but spot surface has larger area and microretentive appearance. Caries of enamel and dentin were treated with a noncontact preparation. It was possible to remove the old insufficient fillings, except for amalgam or metal alloys. The average number of pulses was 111.22 (SE 67.57). Vibrations of microexplosions during preparation were felt by patients on 14 cavities; however, nobody felt unpleasant pain. The qualities of filling materials in laser cavities were very stable; however, cavo surface margin discoloration of 82-86% of Alfa rating could be a problem. Changes of the color and anatomic form of the tooth were observed in 4-8%. In comparison with the classical treatment, it could be said that the retention and quality of filling materials is the same or very similar.

Plataformas para prospecciones petrolíferas en el mar

The increasing consumption of petroleum makes it necessary to seek new producing areas, especially in the neighbourhood of the main consumption districts. The rock layers containing petroleum often extend beneath the sea, and in such cases the method of extraction of the petroleum involves specialised techniques, which depend on the nature of the site. The first tests were out in the Gulf of Mexico, where the sea is shallow and mainly calm. In Europe the problem is different, since the sea is usually deeper and more agitated, so that the classical drilling methods cannot be applied. To overcome these difficulties the floating platforms were introduced. These are taken to a given site, and fixed there. The French firm Neptune has two such platforms: «Neptune I» and «Neptune-Gascogne», whose functional features are described in this article. These platforms have three fixed points of support on the soil, but in the near future, to be able to reach depths of 200 to 300 m, it will be necessary to do without the fixed points of support, as they greatly limit the use of the platforms. Submergible platforms, with static or dynamic anchorage systems, are being studied, and it is hoped to carry out trials fairly soon.