Drilling Performance Research Articles

Effects of carbide substrate properties and diamond coating morphology on drilling performance of CFRP composite

Abstract The properties of a cemented carbide tool substrate and diamond coating were studied for the precision drilling of carbon fiber-reinforced plastic (CFRP). The microstructures and mechanical properties of WC–6 wt.% Co substrates using different WC particle sizes were examined to determine correlations between the mechanical properties and the drilling performance. The results demonstrated that WC powders with an average particle size of 2.3 μm were suitable drill substrates. Coatings of either microcrystalline diamond (MCD) or gradient nanocrystalline diamond (NCD) were deposited using hot-filament chemical vapor deposition. A drilling test using T700-grade CFRP was conducted to evaluate the drilling performance, tool wear resistance, and CFRP hole quality achieved based on the diamond coating morphology. In the CFRP drilling tests, the diamond-coated drills showed superior tool lifetimes four times longer than that of the uncoated drill. The MCD-coated drill exhibited good wear resistance compared to the gradient NCD-coated drill; however, the gradient NCD-coated drill demonstrated better machining quality in terms of the delamination factor, surface roughness inside the machined hole, and accuracy of the machining dimensions. In this study, we aimed to develop the optimal tool substrate for the drilling of general-purpose CFRP and proposed directions for the development of diamond coatings to maximize drilling performance.

Improvement of drilling performance by overcoating diamond-like carbon films on diamond-coated drills for carbon fiber reinforced plastics processing

The hardness and hydrogen content of diamond-like carbon (DLC) films vary depending on the film deposition methods and conditions. Carbon fiber reinforced plastics (CFRP), known as hard-to-machine materials, have been widely used for industrial aircrafts that require structural materials. In this study, the effects of the hardness and hydrogen content in DLC films on the drilling performance of CFRP drills were investigated. Various DLC films, prepared using the T-shaped filtered arc deposition method, were used to coat diamond-coated drills for CFRP processing. The drilling test of the CFRP plates revealed that the occurrence of burrs was suppressed using the drill coated with a hard DLC film containing small amounts of hydrogen, classified as a hydrogenated tetrahedral amorphous carbon (ta-C:H) film. The spherical polishing test of the CFRP plate using DLC-coated balls demonstrated that the DLC films containing hydrogen suppressed the adhesion of the resin material constituting the CFRP. The coating of hard DLC films containing small amounts of hydrogen, such as a ta-C:H film, significantly improved the drilling performance of diamond-coated drills for CFRP processing. The performance improvement of CFRP drills expands the range of CFRP processing conditions.

Influence of Weight-on-Bit on Percussive Drilling Performance

A phenomenological model for percussive drilling systems is proposed in this paper to explain the experimentally demonstrated existence of an optimal weight-on-bit (WOB), for which the rate of penetration (ROP) is maximized. Several hypotheses have been previously proposed to explain this universal characteristic of percussive drilling, including increased wear of the bit, reduced indexing, and poor cleaning of debris under excessive WOB. Motivated by experimental evidence, we instead consider an increase of the pseudo-stiffness of the bit-rock interface (BRI) with increasing WOB, and investigate its effect on the impact energy transmitted to the rock. The 1D model approximates the dynamics underlying the drilling process by assuming that the impact of the hammer generates a longitudinal wave in the bit. It is shown that the BRI pseudo-stiffness influences the incident wave and associated energy transmitted from the bit to the rock. As a consequence, the drilling efficiency is affected by the dependence of the BRI stiffness on the WOB. The model indicates that there exist optimal conditions for the energy transfer from the bit to the rock in terms of the impedance ratio and the BRI stiffness/WOB. Thus it confirms that there is a sweet spot as seen in practice, which suggests that the root cause of the existence of a sweet spot in the ROP-WOB relationship lies in the nature of the BRI laws, rather than with issues related to bit indexing, bit wear, and/or cleaning of the debris.

Error reduction of tracking planned trajectory in a thin oil layer drilling using smart rotary steerable system

Directional drilling which is a controlled drilling process, has been efficiently utilized to reach oil/gas reservoirs. Shale oil/gas development and also the need for extraction from wells that are hardly accessible, have recently introduced the directional drilling process as an interesting method in the oil/gas industry. However, error reduction during tracking the planned path is a challenging issue, especially in the cases of drilling thin oil/gas layers, as they may result in significant errors. In these conditions, it is inevitable to use smart systems (e.g. RSS) for directional drilling. Hence, it is essential to develop intelligent and automated systems for directional drilling. This study aims to introduce an operational control approach for intelligentization of the push-the-bit RSS system that can improve the tracking performance of directional drilling. To describe the borehole evolution, we utilized the Perneder-Detournay's model which has been derived via combining the BHA modeling, rock/bit interaction law and kinematic relationships between them. Considering the existence of delay and uncertainty in this model, the controllers were designed in two cases (system with and without reference inputs) to prove the stability of the system. Afterward, a relatively complicated path including horizontal and sinusoidal section in a thin reservoir layer is designed and then the suggested controller is applied to this trajectory. According to the simulation outcomes, the system was well able to follow the planned trajectory with a too small error and operational RSS force.

Optimization of hot-water ice-coring drills

AbstractHot-water ice-coring drills are often used to recover ice core samples from desirable depths in conjunction with full-scale hot-water drilling systems. However, the recovered cores exhibit varying qualities. The coring performance of a hot-water ice-coring drill depends significantly on the structure of the coring drill head (nozzle angle, diameter and number). To discover the most significant factor affecting ice-coring performance, nine types of drill heads were designed and tested in this study according to the orthogonal test design. Results indicated that the nozzle angle is the most significant factor that affects the coring quality and the optimal angle is ~15°. The number of nozzles is the second most important factor; a large number assists in obtaining ice cores of high quality. The optimal nozzle configuration to recover good quality cores are the following: the nozzle diameter, number of nozzles and nozzle angle are 1 mm, 60 nozzles and 15°, respectively, with the maximum diameter and 2 mm, 60 nozzles and 15°, respectively, with the maximum length.

Coupling rate of penetration and mechanical specific energy to Improve the efficiency of drilling gas wells

Drilling operations for oil or gas wells are very expensive. Optimizing the drilling efficiency and increasing the rate of penetration (ROP) will reduce the overall cost of the drilling operation. Different approaches are utilized to increase the drilling performance including analytical and empirical methods. However, most of the available models have some limitations once they applied for real-time drilling operations. This study presents a new approach for evaluating and improving the drilling operations for real-time applications. Seven ROP models were developed using artificial neural network (ANN) technique. The ANN models were developed using real field data (20,000 data sets) which includes the real-time recording of the surface drilling parameters such as rate of penetration (ROP), weight on bit (WOB), torque, rotation speed (RPM) and mud flow rate (Q). The ANN-based models are able to provide an accurate estimation for the full ROP profile. Thereafter, the predicted ROP was coupled with the calculated MSE in order to optimize the drilling performance. Moreover, and for the first time, a new (ROP/MSE) ratio is suggested, which can be used to assess the drilling operations in a real-time. A new profile of ROP/MSE ratio can be displayed along with the drilling parameter in order to provide a quick and more reliable evaluation for the ongoing drilling operation. The suggested ratio incorporates the impacts of the primary drilling factors which are the drilling speed (ROP) and the required drilling energy (MSE). Also, the seven ANN-based models, developed in this work, can predict the full profile of ROP with an average absolute percentage error (AAPE) of around 7.9% and a correlation coefficient of around 0.92.

Wear performance of surface treated drills in high speed drilling of AISI 304 stainless steel

In the present work, the effect of three surface-treated drills and one AlCrN (Alcrona) coated drill have been investigated at different levels of the cutting speed for drilling holes in AISI 304 SS. Three different high-speed steel (HSS) grades, including M2, M42, and M35, were utilized for the said purpose. Two types of drills, including M2 and M42 grades, were steam tempered (ST), which was performed at a temperature of 850°F to deposit a stable and corrosive resistance magnetite (Fe3O4) layer on the tool surface. One type of drill made from M35 HSS grade was ground (GR), while the other one was coated with ∼4μm thick AlCrN PVD coating. With respect to tool life, M2-ST drill outperformed all other evaluated counterparts with a maximum tool life of 48 holes at 11 m/min cutting speed, while at this cutting speed, the M42-ST tool drilled just 15 holes. The lesser volume fraction of primary carbides present in the microstructure of M2-ST drills was thought to be the reason for its better performance in terms of reduced tool wear/higher tool life. Catastrophic fracture was encountered in the majority of the tests conducted with M35-GR and M35-AlCrN drills. The inferior performance of the former tools was attributed to strain hardening/brittleness induced as a result of grinding, while non-uniformity of the coating along the cutting edge was thought to be the possible cause of the poor performance of the latter drills. Regarding hole quality, M2-ST drills outclassed all other equivalent tools with diametric error ranging from 7 μm to 25 μm and surface roughness variations within 1 μm to 2.60 μm.

The Impact of Recovery Time on Performance in Division I Collegiate Beach Volleyball Players.

Holtgeerts, RN, Gann, J, Jung, HC, and Hey, W. The impact of recovery time on performance in Division I collegiate beach volleyball players. J Strength Cond Res 36(3): 667-673, 2022-The sport of beach volleyball has recently grown significantly at the collegiate level, and collegiate beach volleyball players often practice and compete 5 or 6 days per week during the competitive season. This study examined the effects of the amount of recovery time on performance in Division 1 Collegiate beach volleyball players. Ten female NCAA Division 1 beach volleyball players, aged 20.2 ± 1.23 years, participated in the study. Subjects completed 2 trials consisting of 4 sessions of volleyball play (with a 24-hour recovery trial and 48-hour recovery trial). Trials were randomized and counter balanced. Each trial measured counter-movement jump, 5-10-5 agility time, 3 beach volleyball drills, and scores of a beach volleyball match. Perceived recovery, sleep quality, and rating of perceived exertion were also recorded. The significance level set for the study was p ≤ 0.05. Counter-movement jump showed small but significant increases following the 24-hour recovery period (p ≤ 0.05). 5-10-5 agility test showed significant improvement with the 48-hour recovery period (p ≤ 0.05). Perceived Recovery scores demonstrated significant increases in both recovery periods (p ≤ 0.05). Beach volleyball drill and match performance were not affected by the change in recovery time. These results indicate that, although some physical skills are affected by recovery time, beach volleyball performance as a whole is relatively stable over several days. It is normal for NCAA athletes to play back-to-back days and with little recovery time, and these results indicate that this practice does not negatively affect sport performance.

Effect of tool wear on drilling unidirectional CFRP laminates in different fiber cutting angles

Drilling performance of carbon fiber reinforced polymer (CFRP) aggravates significantly with serious tool wear caused by highly abrasive fibers. Because of the anisotropy of CFRP, the angle between fiber orientation and cutting direction, namely, fiber cutting angle, also plays a crucial part in the drilling performance. To enhance drilling performance, this paper initially conducts a comprehensive experimental study on the effects of tool wear on thrust force, exit temperature, and hole wall defect in different fiber cutting angles in the drilling of unidirectional CFRP. The results demonstrate that the profile of worn cutting edge is an approximate elliptical arc and the half axis lengths of the elliptical arc are utilized to evaluate cutting edge wear. Tool wear on the cutting edge, flank face, and rake face all deteriorates with the number of drilled holes. Tool wear has a more significant influence on thrust force in the fiber cutting angle region of 0~90° than in the fiber cutting angle region of 90~180°. With increasing tool wear, the exit temperature distribution can still be approximate to an ellipse. The variation of exit temperature caused by tool wear in the major axis direction is still no less than that in other directions. In addition, on hole wall, tool wear causes severe crack defects in the fiber cutting angle region of 0~90° and cavity defects in the fiber cutting angle region of 90~180°.

Characterization by Scanning Electron Microscopy on Drill Boride and Drilling Performance of Tool Steels

Characterization by Scanning Electron Microscopy on Drill Boride and Drilling Performance of Tool Steels

Drilling performance of nano-diamond bonded SiC composite abrasives for CFRP laminates by dual-axis grinding wheel system

The design and fabrication of nano-diamond (ND) bonded silicon carbide (SiC) composite material were conducted as an attempt to obtain better drilling performance of SiC abrasives. The ND/SiC composite abrasives were fabricated by mechanical bonding of the NDs on the surface of SiC abrasives with the use of dry particle composing machine together with amorphous silica as a bond material. A comparative study on drilling performance for carbon fiber-reinforced plastic (CFRP) laminates by the SiC abrasives and ND/SiC composite abrasives was performed with dual-axis grinding wheel system. Hole-qualities such as roundness and roughness were improved by using the ND/SiC composite abrasives. Enhanced drilling performance of the ND/SiC composite abrasives was also obtained in terms of feed rate dependence of the thrust force. The ND/SiC composite abrasives could make holes with lower thrust force at higher feed rate, compared with the SiC abrasives due to the enhanced self-dressing effect together with the original drilling performance of the ND abrasive as synergetic effect caused by interfacial design between the ND/SiC composite abrasives and metal matrix in the grinding wheels. These results indicate the new controlling method of holding force of abrasive grains in metal bonded grinding wheel.

Influence of flex-sub on mechanical properties of rotary steerable drilling system

Abstract. In this paper we analysis of the dynamic model of the Rotary Steerable System (RSS) with a single stabilizer and flex-sub. The drill collar and joint are simplified to obtain suitable bottom-hole assembly (BHA) model of mechanical analysis and finite element analysis. Using the BHA uniform stiffness assumption (ignoring the influence of variable section and variable stiffness of drill collar in BHA), the paper takes a method of the longitudinal and transverse bending continuous beam method to analyse the stress of BHA with RSS with the flex-sub under different inclination angles and curvature conditions. In addition, a dynamic analysis model is proposed, and the dynamic stress of drilling tools with RSS is analysed. Through the software of ANSYS, the finite element analysis of the RSS with the flex-sub is carried out to verify the theoretical results. The influence of flex-sub on the steering drilling performance of RSS is studied, and the optimized parameters of flex-sub design are obtained, which provides useful suggestions for the design of RSS.

Characterization of micro-holes drilled in alumina ceramic by the combined pulse laser technique.

Nowadays, combined pulse laser (CPL) technology has shown obvious advantages in alumina ceramic drilling. However, the characterization of micro-holes drilled by the CPL is not clear. In this paper, micro-holes drilled by ns-ms and ns/ms CPLs are systematically compared from the aspects of hole diameter, cracks, spatter deposition, recast layer, re-solidified particles, grain size, and chemical composition. The results show that due to the synchronous output of the nanosecond laser, the ns/ms CPL can eject more melt through expelling of the plasma shock wave; thus, the recast layer, re-solidified particles, and oxygen vacancies are decreased, while the spatter deposition is increased. On the other hand, due to the higher temperature and larger temperature gradient introduced by the nanosecond laser, the hole diameter, cracks, and grain size are increased. Therefore, an ideal CPL method to optimize the drilling performance is proposed. The research results have important guidance for improving the processing quality of the CPL, especially for alumina ceramic laser processing.

Performance analysis of rotary blast-hole drills through machine vibration and coarseness index mapping – A novel approach

• A novel performance evaluation technique for rotary blast-hole drills performance. • Correlation of drill performance with machine-vibration and drill cuttings. • Drill cuttings collection and analysis as per ASTM standard. • Determination of mean particle size using Rosin-Rammler Diagram. • Obtaining Drill Vibration Index and the optimal drill operating regime. The performance of rotary drill machines commonly used in open-pit mines is measured based on the rate of penetration (ROP) and the bit wear. This paper develops a novel performance evaluation technique to obtain optimal drill operating regime through machine vibration and coarseness index mapping. The vibration levels of blast-hole drilling machines in axial and lateral directions were determined using accelerometers placed at the mast. The mean particle size (d) and characteristic particle size distribution curves for the drilled hole were plotted using sieve analysis and Rosin Rammler diagram. ROP showed an increasing trend with Mean particle size (d) with a correlation of R 2 = 0.61 and a decreasing trend with vibration for varied pulldown force and torque at a different rotational speed. A drill vibration index (DVI) is introduced as an indicator of vibration severity of the drill machine, and its relationship was studied with ROP and average mean particle size.

Drilling and mechanical performance analysis on flax-sisal hybrid composite embedded with perforated aluminum foil

This paper focused on the investigation of mechanical, twist drilling performance and microstructural analysis in aluminum foil reinforced sisal flax epoxy composite. Six combinations of composite (SF1–SF6) were fabricated by hand layup method with two different orientation of circular (φ = 5 mm) geometrical patterns in aluminum foil (thickness 0.024 mm) as structural reinforcement. The mechanical properties were determined by the tensile, flexural, impact, and hardness investigation with ASTM test specimens. The machinability of the composites was studied through twist drilling operation (8 mm), and the drilling experiments were designed by the design expert 11.0. The analysis was performed on a CNC milling machine (VF-30 CNC VS) vertical milling center with the different process parameters like spindle speed (500–2000 r/min), feed rate (0.05–0.25 mm/min), and hole pitch (20, 40, and 60 mm) in sliding dry environments at room temperature. The fractured composite samples were examined through a scanning electron microscope to determine the fiber pullout, deboning, and voids between the reinforcement and matrix. The obtained results were shown that the sample with 45° staggered hole with 60 mm hole pitch (SF6) composite holds the excellent mechanical properties like tensile strength (31 MPa), flexural strength (76 MPa), impact strength (1.5 J), and hardness value (23 VHN) compared to other combinations. The effect of hole pitch and spindle speed significantly affects the circularity error.

Experimental investigation on the performance of MQL drilling of AISI 321 stainless steel using nano-graphene enhanced vegetable-oil-based cutting fluid

The present work aims to examine the drilling performance of AISI 321 stainless steel using vegetable-oil-based cutting fluid under different minimum quantity lubrication (MQL) strategies (with and without graphene nanoparticles). Experimental results indicated that MQL drilling with 1.5 wt% of graphene nanoparticles considerably reduced the thrust force (27.4%), torque (64.9%), surface roughness (33.8%) and coefficient of friction (51.7%) at the 30th hole as compared to pure MQL condition and also improved the tool life. In brief, the sufficient quantity of graphene nanoparticles in nanofluid MQL drilling can boost the lubrication performance and increase the stability of lubrication film, which improves the drilling characteristics.

Sustainable drilling performance optimization for Nano SiC reinforced Al matrix composites

ABSTRACT Metal Matrix Composites (MMC) reinforced by nanoparticles are competent materials, appropriate for functional and structural applications. Green manufacturing is a style for mechanized that minimizes dissipate and contamination. The pollution prevention resolves in manufacturing industries to expand and execute various environmentally-friendly strategies. The primary purpose of green machining is to hold up future generations by attaining process sustainability. In the present investigation, cryogenic machining (CM) of Nanoscaled SiC reinforced Aluminum (Al) matrix composites gives experimental outcomes and also the correlation of its performance with dry machining (DM) and Minimum Quantity Lubrication (MQL). The drilling tests are organized using a vertical machining center (VMC), which is directed by computer numeric control (CNC) employing carbide drills of 10 mm dia with cutting point angles of 90, 118, and 135 degrees. Experiments have planned as per the response surface methodology (RSM) based on Box-Behnken design (BBD). Teaching–Learning-Based Optimization (TLBO) is implemented to optimize the drilling criteria such as the speed of the spindle, feed rate, weight % of nano SiC, and cutting angle. Subsequently, Scanning Electron Microscope (SEM) is utilized to inspect the subsurface of the machined specimen.

Three-dimensional simulation of rock breaking efficiency under various impact drilling loads

Percussion drilling is believed to be an efficient way to enhance the drilling performance, compared with the conventional drilling in deep wells, which could be achieved by applying impact loads above the drill bit. The finite simulation is an efficient method to predict the drilling performance when the drill bit interacts with rocks. In contrast, as results of finite element technology limitation, the conventional way is to apply the displacement or velocity boundary conditions on the bit; however, this is completely different from the real field drilling process. Therefore, in this paper, a 3-D rock-bit physical model is presented to simulate the practical percussion drilling under various types of loads; at the same time, experiment was conducted to validate the effectiveness of the rock-bit model. The results demonstrated that the drilling performance with the rectangular and sinusoidal loads was promoted than the other types of load, and rate of penetration (ROP) increases with increasing of the amplitude of dynamic load, which could provide the theoretical guidance to the down-the-hole drilling tool design, thereby proving a quite efficient and lower cost drilling in the exploration of hard formations.

Didactic biomechanics: a modern trend of scientific research

Topicality. Human movements obey all the physical laws that determine the motion of any material body on the Earth. They include the law of gravity, and Newton's laws, and the laws of hydro-aeromechanics, vibrational and wave phenomena. The vast majority of human movements are performed for a specific purpose and are arbitrary. Such movements are part of motor actions, a set of elementary motor acts aimed at achieving a certain goal. Each motor act consists of indicative, executive and control parts. Human movements and their improvement should be considered as the result of not just interaction with the external environment, but also interaction in which the physical properties of the external environment are purposefully changed. This means that in this way one can purposefully influence the very nature of movement through the adaptive motor reactions of a human in a continuous interaction with the external environment (which can be called external control). Thus, there are internal and external control systems in the management of movements, the coordinated operation of which allows building a motor action of a human. The task of the study is to conduct a comparative biomechanical analysis of the technique of performing the techniques of "elbow lever outward", "elbow lever inward" and "throw with legs grab behind" by experienced workers and cadets of the fourth year of study with the help of optoelectronic system "Qualisys". Research methods. To achieve the set tasks, we have applied such research methods as analysis of scientific and methodological literature as well as documentary materials, methods of registration and analysis of athlete's movements (system of video recording and analysis of athlete's movements, 3D recording of human movements "Qualisys Motion Capture"). The results obtained during the study have been processed with the help of mathematical statistics methods. Results of the research. The results of research indicate the presence of general differences in the technique of performing these drills (total duration of a drill performance; phases for motor tasks solution (parallelism or sequence of motor actions); technique of motor actions)) as well as partial differences, which are characteristic of individual components of a particular technique (duration and the sequence of individual actions in the overall structure of the movements; the nature and features of their implementation). The main difference, which also serves as the most important biomechanical criterion for the effectiveness of technique implementation, is the time duration. Conclusions. The results of comparative analysis of techniques, performed by experienced employees and cadets of the fourth year of study allowed to establish that the composition of motor actions is the same in these groups, i.e. there are seizures, there are strikes, medial and lateral rotations of the upper imaginary offenders’ extremities and more. One of the most important features is the structural sequence of these motor actions.

The influence of thermal treatment on rock\u2013bit interaction: a study of a combined thermo\u2013mechanical drilling (CTMD) concept

To improve the economics and viability of accessing deep georesources, we propose a combined thermo–mechanical drilling (CTMD) method, employing a heat source to facilitate the mechanical removal of rock, with the aim of increasing drilling performance and thereby reducing the overall costs, especially for deep wells in hard rocks. In this work, we employ a novel experiment setup to investigate the main parameters of interest during the interaction of a cutter with the rock material, and we test untreated and thermally treated sandstone and granite, to understand the underlying rock removal mechanism and the resulting drilling performance improvements achievable with the new approach. We find that the rock removal process can be divided into three main regimes: first, a wear-dominated regime, followed by a compression-based progression of the tool at large penetrations, and a final tool fall-back regime for increasing scratch distances. We calculate the compressive rock strengths from our tests to validate the above regime hypothesis, and they are in good agreement with literature data, explaining the strength reduction after treatment of the material by extensive induced thermal cracking of the rock. We evaluate the new method’s drilling performance and confirm that thermal cracks in the rock can considerably enhance subsequent mechanical rock removal rates and related drilling performance by one order of magnitude in granite, while mainly reducing the wear rates of the cutting tools in sandstone.