Drilling Vibrations Research Articles

One-Dimensional Convolutional Neural Network for Drill Bit Failure Detection in Rotary Percussion Drilling

Drill bit failure is a prominent concern in the drilling process of any mine, as it can lead to increased mining costs. Over the years, the detection of drill bit failure has been based on the operator’s skills and experience, which are subjective and susceptible to errors. To enhance the efficiency of mining operations, it is necessary to implement applications of artificial intelligence to produce a superior method for drill bit monitoring. This research proposes a new and reliable method to detect drill bit failure in rotary percussion drills using deep learning: a one-dimensional convolutional neural network (1D CNN) with time-acceleration as input data. 18 m3 of granite rock were drilled horizontally using a rock drill and intact tungsten carbide drill bits. The time acceleration of drill vibrations was measured using acceleration sensors mounted on the guide cell of the rock drill. The drill bit failure detection model was evaluated on five drilling conditions: normal, defective, abrasion, high pressure, and misdirection. The model achieved a classification accuracy of 88.7%. The proposed model was compared to three state-of-the-art (SOTA) deep learning neural networks. The model outperformed SOTA methods in terms of classification accuracy. Our method provides an automatic and reliable way to detect drill bit failure in rotary percussion drills.

Evaluating the hole quality produced by vibratory drilling: additive manufactured PLA+

Improving the surface quality of additive manufactured parts like poly lactic acid (+) is an important study that is currently being carried out by researchers. To reach the high-quality, different conventional and nonconventional methods are applied. In this study, the capability of ultrasonic vibration in drilling of an additive manufactured poly lactic acid (+)was examined. The process was implemented in two methods: conventional and vibratory drilling. Then, thrust force and chip type were analyzed, and the effect of them on surface roughness, delamination, circularity, and cylindricality have been investigated. As a result, it was indicated that lower thrust force and broken chips, which were generated in ultrasonic drilling, caused the surface quality parameters to be improved compared to the conventional method.

The influence of human interaction on the vibration of hand-held human-machine systems – The effect of body posture, feed force, and gripping forces on the vibration of hammer drills

In hand-held human machine systems the biodynamic response of the human hand arm system influences the overall dynamic behavior. The biodynamic response of the hand arm system is affected by several influencing factors. These influencing factors include the feed force, body posture, gripping force, and anthropometric properties. In present studies the importance of the gripping force on the biodynamic response is highlighted. In the state of the art; however, the magnitude of gripping forces as well as the influence of the human factors body posture and feed force on hammer drills for a larger group of professional users is unclear. To analyze the influence that these human factors have on hammer drill vibrations, a study with 15 professional power tool test personnel has been conducted. Characteristic gripping force values have been measured (Median: 84 N–156 N at the main handle, 10 N–30 N on the auxiliary handle) for different feed forces (100 N, 150 N, 200 N) and body postures. Then the influence of body posture, feed force, and gripping force on the hammer drill vibration is determined. A significant influence of the body posture (ANOVA: p = .003, r = .367) on the RMS acceleration of the main handle was observed. Furthermore, the feed force has a significant influence on the vibration of the hammer-drill for some groups. The data also demonstrates that for increasing gripping forces, the RMS of the acceleration and frequency weighted acceleration ahv on the main and auxiliary handle decrease. The findings of this study represent a starting point for the development of adjustable hand-arm models for the reproducible vibration assessment of power tools.

Research on Formation Identification Based on Drilling Shock and Vibration Parameters and Energy Principle

In geotechnical engineering and geological survey, the stratum structure and its corresponding physical and mechanical properties are the most concerned. The stratum structure not only affects the safety of the project but also plays a decisive role in the construction method and construction sequence. In this paper, a new type of stratum geological interface recognition system is adopted, and an R-20 rotary drilling rig is used to conduct on-site drilling experiments for a granite site with no ventilation. The research results show that the system can monitor and record the main parameters (axial pressure, drilling rate, rotation speed, flushing fluid pressure, and torque) of the drilling rig during the drilling process. The comparative analysis of monitoring data and on-site survey results shows that different drilling parameters have different sensitivities to changes in the formation structure. According to the prediction accuracy, the ranking from high to low is drilling rate, axial pressure, torque, rotation speed, and flushing fluid pressure. In drilling engineering, by observing the change law of drilling rig parameters, not only can the position of the special rock mass interlayer be predicted, but also the stratum structure and strength can be identified, and the prediction formula is also given. Based on the established drilling specific energy formula, the energy analysis method is used to predict the formation structure and compressive strength, and the corresponding prediction formula is given. The research results show that, compared with the single drilling parameter prediction method, the rock-soil structure and strength identification method based on energy theory has higher prediction accuracy and can meet engineering needs.

Dynamic characteristic analysis of micro-hole gun drill based on ANSYS

This paper takes different material properties of gun drill as the research object. ANSYS software is used in the dynamic characteristic analysis of gun drills of different materials. According to modal analysis theory and experiment, the natural frequency and vibration mode of the drill are obtained. The analysis results show that the cemented carbide gun drill after the cubic boron nitride treatment can better withstand bending vibration and torsion during the working process. It is found that the natural frequency of the treated cemented carbide gun drill is very different from that of other materials. The performance micro-hole gun drill provides a certain theoretical basis, and at the same time provides a reference for reducing the vibration and deformation of the gun drill.

Comparative Analysis of Cutting Forces, Torques, and Vibration in Drilling of Bovine, Porcine, and Artificial Femur Bone with Considerations for Robot Effector Stiffness.

Bone drilling is known as one of the most sensitive milling processes in biomedical engineering field. Fracture behavior of this cortical bone during drilling has attracted the attention of many researchers; however, there are still impending concerns such as necrosis, tool breakage, and microcracks due to high cutting forces, torques, and high vibration while drilling. This paper presents a comparative analysis of the cutting forces, torques, and vibration resulted on different bone samples (bovine, porcine, and artificial femur) using a 6dof Robot arm effector with considerations of its stiffness effects. Experiments were conducted on two spindle speeds of 1000 and 1500 rpm with a drill bit diameter of 2.5 mm and 6 mm depth of cut. The results obtained from the specimens were processed and analyzed using MATLAB R2015b and Visio 2000 software; these results were then compared with a prior test using manual and conventional drilling methods. The results obtained show that there is a significant drop in the average values of maximum drilling force for all the bone specimens when the spindle speed changes from 1000 rev/min to 1500 rev/min, with a drop from (20.07 to 12.34 N), approximately 23.85% for bovine, (11.25 to 8.14 N) with 16.03% for porcine, and (5.62 to 3.86 N) with 33.99% for artificial femur. The maximum average values of torque also decrease from 41.2 to 24.2 N·mm (bovine), 37.0 to 21.6 N·mm (porcine), and 13.6 to 6.7 N·mm (artificial femur), respectively. At an increase in the spindle speed, the vibration amplitude on all the bone samples also increases considerably. The variation in drilling force, torque, and vibration in our result also confirm that the stiffness of the robot effector joint has negative effect on the bone precision during drilling process.

Drilling Vibration in a Micro-Drilling Process Using a Gas Bearing Spindle

In industry, high-density packaging technology is an unavoidable requirement. Therefore, the drilling hole of printed circuit boards, PCB, requires being much smaller, even down to 0.1 mm or less. Drill fractures are frequently found in the micro drilling process due to the micro scale, hole-location errors, reaming. In all micro drilling failure cases, there existed a large vibration or instability is frequently found because of the insufficient rigidity of supports for a system with a super-high spinning speed. To improve the drilling quality and avoid drill breakage, the effects of support stiffness and high rotational speed of the vibration in the micro drilling process must be studied. Most investigations on the vibration of micro drilling are focused on only drill self-structure. However, in an actual engineering application, the micro drill must be attached in a bearing spindle system. This study considers the vibration of a micro drill with a gas bearing spindle. Hence, it includes the effects of the rotation speed, air pressure, and clearance of gas bearing on the vibration in a micro drilling process. After constructing the governing equations of the system, the numerical analysis by the Fortran programming is performed to solve for the frequency and amplitude response of the spindle system over time. The results indicated that the spindle with the gas bearings effect increased the vibration in the micro-drilling process.

Experimental Design, Instrumentation, and Testing of a Laboratory-Scale Test Rig for Torsional Vibrations—The Next Generation

Drilling technology and specially drilling equipment has dramatically changed in the last 10 years through intensive and innovative technologies, both in terms of hardware and software. While engineers are focusing on safer, faster, and more reliable than ever technologies, big data and automation are currently considered the way forward to achieve these goals. Especially when automation concepts are proposed, the prior testing and qualification under a laboratory-controlled environment are mandatory. Drilling simulators have been hugely successful in training industry personnel and academic professionals. A big reason for its success lies in the seamless integration of hardware and software to include an interactive user interface. Physical experimental simulators have the advantage of exposing the user with visual and auditive aids to better understand the real process. This paper provides an insight into the construction and results obtained using a dedicated laboratory setup, which is also configured to various levels of automation. The setup is capable of safely recreating drilling vibrations that occur in wells, including stick-slip vibrations, which are detrimental in nature. With advanced sensor capabilities, the impact of proper sampling rates on the diagnosis of stick-slip vibrations has been analyzed in the paper. The results show that these vibrations are not only dependent on drilling parameters, such as rotational speed (RPM), torque, and weight on bit, but also on stick-slip parameters, such as bit sticking time period and frequency.

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.

Development status and application prospect of semi-active vibration reduction technology for down-hole drilling tools

Domestic and foreign oil companies have been constantly increasing the research and development investment in underground shock absorber, to reduce the vibration and shock of drilling tool under hard rock drilling environments, enhance the rate of penetration and decrease drilling cost under the premise of ensuring the normal life of drill string components and stable bit weight. Based on this, this paper has focused on the working principal of magneto-rheological fluid (MRF) semi-active damper, the composition of MRF and its internal parameters’ impact on the damping characteristics, combining with the status quo at home and abroad of down-hole vibration technology. Meanwhile, the test analysis of semi-active damping technology was conducted. And the results showed that semi-active vibration technology had greatly weakened the vibration level while improved the rate of penetration, guaranteed the service life of bit and other drill-string components, reduced additional tripping times and effectively solved the problems of bit weight instability and low penetration rate etc., caused by drill vibration. Therefore, in the current situation of worldwide oil price downturn, it has become increasingly prominent to reduce cost and increase efficiency, and it’s particularly necessary to research on the shock absorbers of down-hole drilling tools in China.

Research on the Potential of Spherical Triboelectric Nanogenerator for Collecting Vibration Energy and Measuring Vibration.

The traditional downhole drilling vibration measurement methods which use cable or battery as power supplies increase the drilling costs and reduce the drilling efficiency. This paper proposes a spherical triboelectric nanogenerator, which shows the potential to collect the downhole vibration energy and measure the vibration frequency in a self-powered model. The power generation tests show that the output signal amplitude of the spherical triboelectric nanogenerator increases as the vibration frequency increases, and it can reach a maximum output voltage of 70 V, a maximum current of 3.3 × 10−5 A, and a maximum power of 10.9 × 10−9 W at 8 Hz when a 10-ohm resistor is connected. Therefore, if the power generation is stored for a certain period of time when numbers of the spherical triboelectric nanogenerators are connected in parallel, it may provide intermittent power for the low-power downhole measurement instruments. In addition, the sensing tests show that the measurement range is 0 to 8 Hz, the test error is less than 2%, the applicable working environment temperature is below 100 degrees Celsius, and the installation distance between the spherical triboelectric nanogenerator and the vibration source should be less than the critical value of 150 cm because the output signal amplitude is inversely proportional to the distance.

Vibration of drilling motors in unconventional oil and gas exploration with a miniature recorder

A low-cost and miniature vibration recorder was developed to capture the vibration data of drilling motors for their health assessment. The recorder is installed in the rotor catch of a conventional drilling motor in such a way that no additional length is added to the bottom hole assembly. The recorder is fitted with two triaxial vibration accelerometers with different ranges, a rate gyroscope, a temperature sensor, and an integrated circuit (IC) for timestamps. The recorder can log data over the full operation cycle of a drilling motor, including vibration during surface activities and downhole operation. It allows the vibration recorders to be easily deployed to motor operations. The vibration recorder has been deployed to drilling motors in unconventional horizontal wells. The data analysis showed that the recorder captured vibration data from the installation of the recorder in maintenance bases until the return of the tools. Not only downhole drilling vibration data were successfully obtained, but also surface vibration data during shipment, and rig-side handling was recorded; the vibration recorders provided adequate information of a drilling motor to asset owners for maintenance and operation optimisation.

On the effect of load on vibration amplitude in ultrasonic-assisted drilling

The ultrasonic-assisted drilling (UAD) process is a technology that applies ultrasonic vibrations in the feed direction of the drill to improve drilling conditions and productivity. In recent years, UAD has been the subject of extensive research due to its advantages over the conventional drilling (CD) process, these being reported as thrust force and torque reduction, burr height reduction, improvements in surface roughness, and hole accuracy. The results of the research also showed that these benefits do not necessarily equally occur for all drilling conditions but can vary with machining and ultrasonic conditions. In particular, it is found that the drill vibration amplitude is a key factor in determining UAD benefits. However, a critical difficulty is that the all-important matter of the drill vibration amplitude at the point of material engagement, the so-called “down-the-hole” amplitude, is not known due to inaccessibility. This difficulty, not faced, for example by the ultrasonic-assisted turning (UAT) process due to its visual access, has prevented measurement of load effects on UAD, as well as verification of analytical models of the process. In this study, a technique to measure the effect of load on drill vibration amplitude during UAD is presented. The technique is based on examining the surface of the drilled hole, where minute, oscillatory traces of the vibrating drill tip are found that correspond to drill tip vibrational amplitude. This data, when coupled with in-process laser vibration measurements at the drill chuck, as well as no load amplitude measurements, permit the effects of load on vibration amplitude to be determined. Results have shown that drilling loads cause measurable reductions in drill vibration amplitude and must be accounted for in UAD procedures.

Fully coupled end-to-end drilling optimization model using machine learning

Drilling optimization has been studied extensively given its impact on an oil and gas project – especially in a low-price environment. This is generally approached by optimizing the rate of penetration (ROP) of the well, which may not always be the best strategy. Additionally, optimization strategies rarely include the effect of torsional drilling vibrations (stick-slip) – the biggest ROP inhibitor. As such, most optimization studies have attempted to optimize only one drilling metric – ROP, mechanical specific energy (MSE) or vibrations – independent of the other, despite their interaction downhole. This does not represent bottom hole conditions accurately. This paper introduces a method of coupling several downhole parameters using machine learning algorithms. Individual models for ROP, torque on bit (TOB), MSE, and stick-slip are built using a data-driven modeling approach using the random forests algorithm. The random forest algorithm is used given its lower error rate in modeling ROP (11%), TOB (13%), and classifying drilling vibrations (F-1 score of 0.94) as compared to other machine learning algorithms evaluated in this paper (linear regression, k nearest neighbors, bagging, and neural networks). The models are coupled by building them conjointly during training. The model uses weight-on-bit (WOB), rotary speed, flowrate, and rock strength as inputs to provide an optimal set of these input parameters to use ahead of the bit for optimal drilling. The coupled model was evaluated to optimize ROP and MSE on validation data. ROP increased by 31% and MSE decreased by 49% on average with the use of this optimization model. A case study from the Williston Basin is discussed to illustrate the practical application of this model.

Characteristics and mechanism of loess landslide induced by drill vibration

In order to reveal the disaster mechanism of loess landslide induced by rig vibration, based on the analysis of typical cases of loess landslide, the disaster process of loess landslide triggered by rig vibration was analyzed through field investigation, physical model test and stress path test. The results showed that the instability mechanism of vibration-type loess landslide was a dynamic process under the action of vibration load. This process can be summarized as follows: stable loess slope – vibration load of drilling rig – adjustment of slope stress – shear failure occurs under continuous load – slope body begins to slide after sliding surface gradually forms – landslide forms

Optimization and prediction of thrust force, vibration and delamination in drilling of functionally graded composite using Taguchi, ANOVA and ANN analysis

Composite materials offers many advantages over traditional materials in terms of weight, strength and design flexibility. However, machining of these materials leads to some critical problems such as delamination, inferior surface finish and excessive tool wear due to their anisotropic and inhomogeneity structure. In particular, in manufacturing of the functionally graded composite (FGC) materials, this situation becomes more complicated since these composites have been made with different stacking sequences. In this work, drilling performance of FGC, depending on delamination, thrust force and vibration, has been investigated experimentally by using different cutting parameters, which are feed rate, spindle speed and material directions (carbon/epoxy and glass/epoxy). From the results of experiments, the material direction has deeply affected the delamination (89.5%) but has rarely affected the thrust force (0.1%) and vibration (8.4%). Feed rate is the most impactful factor on thrust force and vibration generation. Whereas the feed rate has a direct proportion to the thrust force and delamination, the spindle speed has an inverse proportion to these responses. When the results evaluated generally, In addition to that, a surrogate model is created through ANN to estimate the responses or cutting parameters on the drilling process in a wider range.

Design optimization of bottom-hole assembly to reduce drilling vibration

Drilling vibration has been considered as one of the major undesirable drill-string dynamics. This paper establishes a framework to optimize the design of the bottom hole assembly (BHA) such that the BHA structure is resilient against vibration. Firstly, a high-fidelity BHA model is established using the finite element method (FEM), which considers the buckling effects caused by the weight on bit (WOB) and the contact between stabilizers and wellbore. Then, vibration indices, such as the BHA strain energy and the stabilizer side force, are derived using the FEM model to evaluate BHA vibration. The stabilizer positions can determine the indices through influencing the boundary conditions; therefore, designing stabilizer positions to reduce drilling vibration can be formulated as an optimization problem to minimize the BHA vibration indices over the operational range. The cost function is non-convex within feasible domain and cannot be expressed explicitly in terms of stabilizer positions. The derivative-free genetic algorithm (GA) is selected to solve the non-convex problem, where parallel computation is implemented to expedite the computational process. For model verification, the finite element analysis of a BHA is conducted and compared against analytical solutions and existing literature and shows a good agreement. A production BHA is optimized following the proposed method. GA can optimize the stabilizer positions with high accuracy and low computational cost. The strain energy and stabilizer side force of the redesigned BHA are significantly reduced compared with the original design, which results in a much better BHA dynamic performance and less drilling vibration.

The Effect of Seed Drill Vibration on the Seed Spacing Uniformity in Row in Lentil Planting

Sıra üzeri tohum dağılım düzgünlüğü, bitkinin gelişimine ve verimine etkili önemli parametrelerden biridir. Sıra üzeri tohum dağılım düzgünlüğünün bulunmasında, laboratuvar ortamında yapışkan bant deneme düzeneğinden yararlanılır. Bu çalışmada, mercimek tohumunun normal sıraya ekiminde, ekim makinası titreşiminin sıra üzeri tohum dağılım düzgünlüğüne olan etkisi incelenmiştir. Ekim makinası titreşiminin sıra üzeri tohum dağılım düzgünlüğüne olan etkisini saptanmak için, normal sıraya ekimde kullanılan λ iyilik kriteri ve Vf varyasyon faktörü değerlerinden yararlanılmıştır. Araştırma sonuçlarına göre, titreşimin etkisiyle sıra üzeri tohum dağılım düzgünlüğünün kötüleştiği belirlenmiştir. Varyasyon faktörü değeri (Vf) 1.1’den büyük çıkarak sıra üzeri tohum dağılımını, poisson karakterinden negatif binomiyal karaktere dönüştürmüştür. İyilik kriterine (λ) göre yapılan değerlendirmede ise titreşimin etkisiyle sıra üzeri tohum dağılım düzgünlüğü oranının %55 sınır değerinin altında kalmasına (yetersiz) neden olmuştur.

Effect of chilled air on delamination, induced vibration, burr formation and surface roughness in CFRP drilling: a comparative study

Exemplary mechanical properties made carbon fiber reinforced polymer (CFRP) laminates to find their place in automotive, defence and process industries. In this work, a comprehensive investigation is carried out on the vibration, thrust force, fiber pull-out, surface roughness and delamination while drilling CFRP laminates. The drilling is accomplished with different cutting velocities and feed rates under two environment viz. dry and chilled air. The investigation revealed the dominance of feed rate over cutting velocity on the measured output parameters. Drilling-induced vibrations are found to be increasing with increased feed rates. Under identical machining condition, chilled air environment could reduce the delamination factor to the maximum of about 19.49% and thus helps in mitigating the delamination and achieving good quality drilled holes.

Time-optimal, minimum-jerk, and acceleration continuous looping and stitching trajectory generation for 5-axis on-the-fly laser drilling

Abstract The process of on-the-fly laser drilling is capable of achieving high throughputs and offers a highly productive approach for producing pre-defined groups of holes (clusters) to be laser drilled on freeform surfaced parts. On-the-fly drilling also presents different technological requirements, needing a different kind of trajectory optimization solutions. Current machine tool controllers are not equipped with appropriate trajectory functions that can take full advantage of the achievable laser drilling speeds. This paper presents the novel idea of applying optimized looping and stitching trajectories (by solving for time optimal trajectories for individual machine axis and choosing the minimum value of the integral square of jerk) for looping a cluster during multiple laser drilling passes, or making a connection between consecutive clusters with given position and velocity boundary conditions. While finding the minimal motion cycle time and minimizing vibrations transmitted to the laser optics causing misalignment (requiring significant manufacturing stoppage for optics realignment). The produced smooth and time optimal trajectories, hand-in-hand with cluster trajectory optimization, proved to reduce both the total drilling cycle time and vibrations transmitted through 5-axis machine to the laser optics. In detail, when compared to currently used on-the-fly drilling methods in industry today (Ex. at Pratt and Whitney Canada), ∼6% reduction in overall cycle time was observed for specific part examples due to the avoidance of unnecessary accelerations and decelerations between hole locations. In individual connecting trajectory instances within part drilling process, up to ∼62% connection time reduction was observed. Furthermore, a substantial improvement of up to ∼56% increase in the motion smoothness compared to using direct linear interpolation between the target hole locations due to abrupt start-stop motions between consecutive clusters and before repeated drilling of the same cluster.