Types Of Drills Research Articles

GEOMETRIA DAS BROCAS HELICOIDAIS E SUA APLICAÇÃO NA INDÚSTRIA

The drilling process is an extremely important event in the machining processes of materials.For this operation to occur, the use of drills is essential. In the historical context, drills arecharacterized as one of the oldest machining tools developed by man, with the first records ofsimilar tools dating back to ancient Egypt, where cylindrical metallic structures with sharp endswere rotated with the help of a rope and an arc for producing holes in wood or low hardnessmaterials. Currently, the use of drills is diverse and their use in the industrial context isincreasing. The geometry of this type of tool has undergone considerable evolution withtechnological development, however, the drills still use the shearing mechanism, which in turncharacterizes drilling as a conventional machining process. Regarding the machining ofmetallic materials, the models and types of drills can be diverse and their application will berelated to the type of operation that will be performed. For this reason, twist drills must havegeometric characteristics and resistance inherent to the material from which they aremanufactured. These characteristics must be such that they best optimize resistance to fatigueand buckling, durability, and suitability for cutting parameters, with the aim of promotingefficient drilling and free from dimensional and geometric deviations, guaranteeing theprecision and tolerance required in the project. In this context, the present work seeks to addressthe design and geometry of twist drills, promoting a discussion about their growing use in themechanical industry and their economic impacts.

Optimization of Drilling Parameters in Natural Fibers Composite Plates Based on Grey Relational Analysis

ABSTRACT This study focuses on optimizing drilling parameters to minimize delamination, circularity error, and cylindricity in natural fiber composites through a comprehensive full factorial Design of Experiments (DoE) combined with Grey Relational Analysis (GRA). The novelty of this work lies in its systematic integration of these methods to evaluate the effects of spindle speed, feed rate, and drill type (HSS, HSS-Co, and Solid Carbide) on hole quality, providing a robust framework for multi-response optimization. Results reveal that feed rate is the most significant factor, with optimal conditions – lower feed rates (0.04 mm/rev) and moderate speeds (1592 rpm) – delivering reduced delamination and improved hole quality. Among the tested drills, Solid Carbide demonstrated superior performance with the lowest delamination and cylindricity errors. This study highlights the potential of systematic parameter optimization to advance eco-friendly composite manufacturing and enhance drilling precision.

Evaluation of Bone Density for Primary Implant Stability Using a Newly Designed Drill: An In Vitro Study on Polyurethane Bone Blocks.

Bone density is an important factor for long-term implant success. Peri-implant bone density evaluation before implant placement can be useful for treatment planning, such as the selection of proper implant size or drilling protocol in each case. In this study, we aimed to establish an objective intraoperative bone density evaluation method by measuring the drilling torque value using a newly designed density measurement drill. Drilling torque value measurement was performed intraoperatively using three types of drills; two previously reported drills and a newly designed drill as a density measurement drill. Polyurethane bone blocks of different densities (D1-D4) were used in this experiment. After the measurement, implants were inserted based on the scheduled plan, and insertion torque (IT) and implant stability quotient (ISQ) were measured to assess primary implant stability. The drilling torque value increased with the bone blocks' density, and there were significant differences among different densities in all groups (p < 0.05). The drilling torque value showed a positive correlation with IT in all groups (p < 0.05). In addition, the drilling torque value increased with the increase in ISQ in all groups. Within the limitations of this study, a newly designed density measurement drill was able to classify D1-D4 in polyurethane bone blocks despite its narrow diameter, and an objective intraoperative bone evaluation can be achieved. An intraoperative assessment of the drilling torque value can predict primary implant stability and provide valuable information for intraoperative treatment planning, such as undersized drilling protocol and implant size change.

Prediction of Delamination Defects in Drilling of Carbon Fiber Reinforced Polymers Using a Regression-Based Approach

Carbon fiber-reinforced polymer (CFRP) structures have been increasingly used in various aerospace sectors due to their outstanding mechanical properties in recent years. However, the poor machinability of CFRP plates, combined with the inhomogeneous behavior of fibers, poses a challenge for manufacturers and researchers to define the critical factors and conditions necessary to ensure the quality of holes in CFRP structures. This study aims to analyze the effect of drilling parameters on CFRP delamination and to predict hole quality using a regression-based approach. The design of the experiment (DOE) was conducted using Taguchi’s L9 3-level orthogonal array. The input drilling variables included the feed rate, spindle speed, and three different drill types. A regression-based model using partial least squares (PLS) was developed to predict delamination defects during the drilling of CFRP plates. The PLS model demonstrated high accuracy in predicting delamination defects, with a Mean Squared Error (MSE) of 0.0045, corresponding to an accuracy of approximately 99.6%, enabling the rapid estimation of delamination. The model’s predictions were closely aligned with the experimental results, although some deviations were observed due to tool inefficiencies, particularly with end mill cutters. These findings offer valuable insights for researchers and practitioners, enhancing the understanding of delamination in CFRPs and identifying areas for further investigation.

Ratio of accelerations to decelerations in Women’s division I lacrosse

This study analyzed the differences by position in acceleration, deceleration, and the ratio of accelerations to decelerations in drills and quarters of games (Q1-Q4). Data were collected in 23 female collegiate lacrosse athletes (20.8 ± 1.5 years, 168.3 ± 6.1 cm), consisting of ten midfielders, five defenders, and eight attackers. Drills were categorized as: stickwork (SW), small-sided games (SSG), warm-up (WU), active recovery (AR), individual skills (IS), scrimmage, and conditioning. AR (0.31 ± 0.09 accelerations/min) and WU (0.47 ± 0.07 accelerations/min) showed the lowest number of accelerations, and conditioning and SW were the highest (&gt;1.0 accelerations/min). Conditioning showed the highest demand for decelerations (0.37 ± 0.14 decelerations/min) and AR and WU had the fewest (0.10 ± 0.04 decelerations/min). AR, IS, SW, and WU all had higher acceleration/deceleration ratios (4:1 to 5.7:1) than the remaining drill types (p = .000 - .050, 3:1-4:1). Q1 had a higher acceleration demand (0.72 ± 0.52 accelerations/minute) than the remaining three quarters (0.57 - 0.67 accelerations/min). The game demand in decelerations was approximately 0.20 decelerations/minute across all quarters and the acceleration/deceleration ratio was approximately 4:1, with the exception of defenders in Q1 who had 6:1 ratio. There is a large demand for accelerations in field lacrosse with no positional differences, and training should be devoted towards this skill.

Recognition of Artificial Gases Formed during Drill-Bit Metamorphism Using Advanced Mud Gas

Drill-bit metamorphism (DBM) is the process of thermal degradation of drilling fluid at the interface of the bit and rock due to the overheating of the bit. The heat generated by the drill when drilling into a rock formation promotes the generation of artificial hydrocarbon and non-hydrocarbon gas, changing the composition of the gas. The objective of this work is to recognize and evaluate artificial gases originating from DBM in wells targeting oil accumulations in pre-salt carbonates in the Santos Basin, Brazil. For the evaluation, chromatographic data from advanced mud gas equipment, drilling parameters, drill type, and lithology were used. The molar concentrations of gases and gas ratios (especially ethene/ethene+ethane and dryness) were analyzed, which identified the occurrence of DBM. DBM is most severe when wells penetrate igneous and carbonate rocks with diamond-impregnated drill bits. The rate of penetration, weight on bit, and rotation per minute were evaluated together with gas data but did not present good correlations to assist in identifying DBM. The depth intervals over which artificial gases formed during DBM are recognized should not be used to infer pay zones or predict the composition and properties of reservoir fluids because the gas composition is completely changed.

Investigating the impact of drill material on hole quality in jute/palm fiber reinforced hybrid composite drilling with uncertainty analysis

This study presents a method for modelling, predicting, and evaluating the impact of drill materials on the drilling process of hybrid palm/jute polyester composites, with the aim of enhancing hole quality regarding delamination, circularity, and cylindricity. Three drill materials, including High-Speed Steel (HSS), 5 % Cobalt-coated High-Speed Steel (HSS-Co5), and Solid Carbide drills were tested, and their impacts on drilling performance were assessed. Through thorough experimentation and statistical analysis, significant differences in results were observed between HSS drills and both HSS-Co5 and Solid Carbide drills. However, the variation in results between HSS-Co5 and Solid Carbide drill results was minimal. Additionally, the findings highlight notable disparities among drill types concerning uncertainty. The results also indicate that feed rate, drill material, and their interaction play crucial roles in determining drilling efficiency. Specifically, HSS drills consistently outperformed HSS-Co5 and Solid carbide drills, demonstrating superior performance in minimizing delamination, improving circularity, and enhancing cylindricity along with lower uncertainty.

CONTROL OF DEVIATIONS FROM CIRCULARITY WHEN DRILLING POLYMERIC MATERIALS

Polymeric materials represent synthetic macromolecular products, from which objects of various shapes can be manufactured, through mechanical or thermal processing. These materials are used in various industries due to their versatility and ability to adapt to various applications. The paper presents an analysis of deviations from circularity in the drilling process of three types of polymeric materials: PA6 (polyamide), PEHD (high-density polyethylene) and POMC (polyacetal). The main purpose of this analysis is to evaluate and measure the deviations from circularity in the drilled plates using specific drills on the EMCO MILL 55 CNC machine and the precise determination of these deviations is realized with the help of the Sinowon 3D measuring machine. In the context of the processing of polymeric materials, both technical performance criteria and their associated factors in drilling operations are examined. In the study, two types of helical drills were used, with two rectilinear cutting edges, having different diameters, Ø8 mm and Ø10 mm, made of high-speed steel.

Evacuation of a Paediatric Hospital Ward in Italy: Lessons Learnt From an Announced Evacuation Drill

The process of evacuating a hospital ward is a complex task that involves several challenges related to emergency protocols, such as the need for assisted evacuation, the staff/patient ratio, and the functional limitations of patients. The purpose of this work is to present a possible sequence of events that can take place during an evacuation drill in a paediatric hospital ward. This is deemed to provide guidance in performing such type of drills and investigate assisted evacuation timelines. The drill was conducted inside a paediatric ward in Italy, at that time closed for maintenance, with the help of figurants emulating paediatric patients. The medical personnel were the ones normally working inside the facility. The activity was video recorded and summarised in a written report. This allowed the analysis of the drill and the reconstruction of typical set of events and timelines that take place in such type of evacuation drill scenarios.

Investigating Twist Drill Design Influence on Thrust Force and Surface Roughness in Drilling AFRP/ Al7075-T6 Stacks Materials

Drilling Aramid Fiber-Reinforced Plastic (AFRP) presents unique challenges when compared to drilling other composite panels. These difficulties arise from the high-toughness characteristics of aramid fibers, which exhibit a tendency for ductile deformation during the drilling process. This research explores the influence of drill bit design on the drilling process stack-up materials, which comprise Aramid Fiber Reinforced Plastic Composite Laminates (AFRP) and Aluminum Al7075-T6. Three distinct bit designs were employed in the experiment, conducted on a Computer Numerical Control (CNC) machine operating at a spindle speed of 2000 rev/min and a feed rate of 0.05 mm/rev. To measure thrust force during drilling, a dynamometer was integrated into the setup. Subsequently, a roughness tester was utilized to assess the hole surface roughness of the stack-up materials. For AFRP materials, the w-point drill design emerged as the optimal choice, reducing thrust force by approximately 5% to 13% compared to other drill bit designs. Conversely, for Al7075-T6 panels, the tapered web drill design demonstrated exceptional results, lowering thrust force by approximately 21% and 50% in comparison to burnishing and w-point drill bits, respectively. In terms of hole surface roughness, the burnishing drill type consistently produced the smoothest surfaces, boasting significant improvements of 44% and 82% when compared to the tapered web and w-point drill bits for AFRP panels. Similarly, for Al7075-T6 panels, the burnishing drill type consistently outperformed the tapered web and w-point drill bits by 74% and 88%, respectively, in achieving a superior hole surface finish. These findings underscore the critical importance of selecting the appropriate drill bit design to optimize thrust force reduction and hole surface quality when working with stack-up materials.

Numerical Study of Drilling Parameters with Al 356 Alloy Using Bacterial Foraging Optimization

A mechanical work piece created industrially frequently contains more than one machining process. Furthermore, it is a common activity of programmers, who make this selection every time a milling and drilling operation is conducted. Tool wear and borehole quality are two essential challenges for high precision drilling procedures, with Al 356 alloy being employed in experimental planning. Drilling specifications will be assessed in this work to get optimal parameters in minimizing the influence of drilling damage on alloy using a swarm-based optimization model. The drilling parameters are optimized using the Bacterial Foraging Optimization (BFO) method, which includes three control factors: depth, feed rate, and spindle speed. Each parameter is designed in three levels, with multiple performance characteristics such as thrust force, surface roughness, and delamination factor. This investigation was carried out in order to obtain the proper optimization. The feed rate, next to the spindle speed, was discovered to be the essential element inducing lamination in drilling, with this phenomenon occurring in each diameter of the drill bit. The results reveal that the feed rate and drill type are the most important parameters influencing the drilling process, and that employing this strategy can successfully improve drilling process outcomes.

Emergency Preparedness Drills for Active and Mass Shootings in Schools.

There is widespread use of emergency preparedness drills in public K-12 schools across the US, but considerable variability exists in the types of protocols used and how these practices are conducted. This review examines research into both "lockdown drills" and "active shooter drills" as it relates to their impact on participants across different outcomes and evaluations of their procedural integrity. A number of studies on lockdown drills yielded largely consistent findings about their impacts, whereas findings related to the effects of active shooter drills are less uniform. The research also demonstrated that lockdown drills, though not active shooter drills, can help participants build skill mastery to be able to successfully deploy the procedure. Differences in how drills impact participants and whether they cultivate skill mastery are largely attributable to the type of drill being conducted. This review suggests that employing clearly defined drill procedures incorporating best practices, coupled with instructional training, can help schools prepare for emergencies without creating trauma for participants.

Influence of cutting tool design on ultrasonic-assisted drilling of fiber metal laminates

Ultrasonic-assisted drilling (UAD) is a machining process that is known to improve the hole quality and reduce cutting forces. Previous studies focused on optimizing cutting parameters to improve the hole quality in conventional drilling (CD) and UAD, as well as to finding the optimum vibration parameters (frequency and amplitude) that will increase the effectiveness of the UAD process. However, the influence of cutting tool type during UAD has been largely overlooked. This research aims to address this gap by analyzing the effect of cutting tool type during UAD on the cutting forces and hole quality in GLARE (Glass Laminate Aluminum-Reinforced Epoxy) laminates. Four types of drills, namely, twist drill (TD), double cone drill (DCD), a step drill type 1 (SD1), and step drill type 2 (SD2) with different step length, were selected for this study. The lowest thrust force (47.04 N) and torque (0.079 Nm) were achieved using twist drill, while DCD, SD1, and SD2 exhibited higher thrust forces (12.81%, 20.69%, 41.3%) and torques (94%, 92%, 91%), respectively. In addition, TD produced high-quality holes with lowest surface roughness (Ra 1.66 μm, Rz 10.58 μm) and minimal burr formation (entry burr height 152.3 μm, exit burr height 69.22 μm). Conversely, DCD, SD1, and SD2 showed higher surface roughness Ra (23%, 16%, 24%) and Rz (16%, 37%, 29%), respectively, compared to the TD. Holes drilled using SD1 and SD2 generally had smaller burr height. Overall, UAD system effectively reduced cutting forces at low spindle speed and feed rate. To achieve higher drilling quality, specifically to reduce the surface roughness and exit burr height, a medium spindle speed of 3000 rpm, a feed rate of 225 mm/min is recommended. Drilling at higher cutting parameters using UAD resulted in a decline in hole quality, except for entry burr height.

Working mechanism and experimental study of split bit

As a component directly acting on the rock in the drilling process, the low efficiency of rock breaking will occur when the bit is drilled. In this paper, a new type of split drill is designed in which the cutting ring can move relatively independently, as well as the kinematic analysis model of the cutting tooth is established. The displacement, velocity and acceleration values of the specific points on the cutting tooth ring of the bit are obtained, which verifies that the small cutting ring at the center of the split cone bit can improve the rock breaking efficiency at the center of the bit. Through the comparison experiments of different types of bits and split bits, the results show that the mechanical drilling rate of split single-tooth bits and triple-tooth bits increased by 11.7% and 12.4%, respectively, in Beipei limestone conditions. Meanwhile, the speed of those two increased by 8.9% and 11.4%, respectively, in Wusheng sandstone conditions, which effectively improved the rock-breaking performance. Combined with the results of bottom hole model, the characteristics of impact, invasion and cutting in the process of tooth rock breaking can be obtained, which effectively improves the rock breaking performance and verifies the rationality of bit design and the correctness of theoretical analysis.

Optimization of drilling parameters on delamination and burr formation in drilling of neat CFRP and hybrid CFRP nano-composites

Carbon fibre-reinforced polymer (CFRP) composites have exceptional mechanical advantages such as high specific strength and stiffness, lightweight, and high damping capacity, making them very attractive for aircraft, aerospace, automotive, marine, and sporting applications. However, various defects such as delamination, burr formation, and surface roughness are observed during the drilling of CFRP composites, which are influenced by various drilling process parameters. In this work, the drilling quality of uni-directional CFRP composites. and the hybrid Al2O3 and hybrid SiC nano-composites are investigated experimentally using different types of drills such as step drill, core drill, and twist drill, as there is a limited study done on the comparative analysis of the impact of the above drills on the delamination factor and burr area on the above CFRP and hybrid nano-composites. The design of the experiment table was developed using response surface methodology (RSM) for input process parameters of spindle speed, feed, drill diameter, and drill type. The output surface characteristics (delamination factor and burr area) of the hole were measured quantitatively using the stereo zoom optical microscope. The main effect plots, contour plots, and analysis of variance (ANOVA) were used to examine the effect of spindle speed, feed, drill diameter, and drill type on exit delamination and burr formation. The analysis of main effect plots, contour plots, and analysis of variance showcased the optimum process parameters, such as a high spindle speed of 5500 rpm, low feed of 0.01 mm/rev, and drill diameter of 4 mm. The step drill demonstrated the least damage mechanism among drill geometries, followed by the twist and core drills. The minimum drilling damage was observed for the Al2O3 hybrid nano-composite compared to the neat CFRP composites.

Action‐time‐controlled tabletop gamification improves physician‒nurse collaborative emergency room evacuation training

AbstractThis article is an example of Lessons from the Field highlighting the practical implementation of a novel time‐controlled mechanism in the gamification of emergency department evacuation training via tabletop exercise. Tabletop exercise is one of the most common drill types for disaster preparedness. It is easy to use, effective, and low in cost, but it has some shortcomings. For example, its lack of authenticity is often criticized. We add a time‐control mechanism to the tabletop exercise and use settings similar to real events in an attempt to increase the authenticity of the tabletop exercise and the learning effect. We completed a 3‐h tabletop gamification of emergency room evacuation, which included a time control mechanism. Medical staff in our emergency department were asked to join this tabletop training. We evaluated the effectiveness of the time‐control tabletop exercise through the results of the pretest and posttests and feedback from the participants. A total of 97 emergency medical staff from the Emergency Department of Cheng Kung University Hospital, including 64 nurses, 29 emergency doctors and four nurse practitioners, participated in this tabletop exercise. After experiencing the time‐control tabletop exercise, the participants significantly improved their approach to mass casualty incidents, their method for evacuating patients, and their triage skills. The correct answer rate for the pretest and post‐test rose from 68.75% to 94.33% with statistically significant. The feedback from the participants also showed that the time‐control tabletop exercise was interesting and could increase learning motivation. The time‐control mechanism had a positive impact on the learning effect. It increased the reality of tabletop exercises, promoted participants' learning motivation, and improved their performance on the test.

Digital Culture and Using Social Media Posts in Foreign Language Learning

The purpose of the paper is to show how technology can be used to make attractive the learning of a foreign language. Social media posts about vocabulary in various foreign languages, for instance, as well as short conversational phrases, could be used to replace the traditional drill types of exercises. Videos that are present could be used to replace the traditional listening exercises. The social media posts could be used as additional material to what is used during class. It is assumed that social media is part of students’ lifestyle, and that learning foreign languages is adapted to modern life.

The Effect of Training in Various Kinds of Active Bottom Drill Drills on Increasing Pasing Accuracy Down Onupper Class Boys Students of Primary School Perumnas Condongcatu

This study aims to determine the effect of various types of active lower passdrill drills on increasing the accuracy of the lower pass in the volleyballgame of upper class male students at SD Perumnas Condongcatur. Thisresearch uses an experimental method, the research design is "ControlGroups Pretest-Posttest Design". PopulationIn this research, there were 24male students from the upper class at SD Perumnas Condongcatur. Thesample taken from the total sampling results was 24 students. Theinstrument used to test the accuracy of the lower fitting is the modifiedBraddy Volley Ball Test.Data analysis uses the t test. The results of theanalysis show that: (1) There is a significant effect of practicing varioustypes of active bottom pass drill drills on increasing pass accuracy involleyball games for upper class male students at SD PerumnasCondongcatur., witht count5,409&gt; t table 2.20, and a significance value of 0.000 &lt; 0.05, a percentage increase of 22.22%. (2) The experimental groupwith various kinds of active lower fitting drill drills was better at increasingthe accuracy of lower fitting male students in the upper classes of SDPerumnas Condongcatur than the control group, with t count2,902&gt; t table = 2.07 and sig. 0.008 &lt; 0.05 and the average difference is 3.6667.

Student Learning Outcomes Using Drill and Practice Type of Computer Assisted Instruction

Student Learning Outcomes Using Drill and Practice Type of Computer Assisted Instruction

Reducing delamination risk with response surface methodology-supported drilling analysis for Nomex® aramid fiber composites

This article presents a comprehensive experimental investigation into the drilling behavior of Nomex®, a type of aramid fiber. The study specifically examines the impact of various cutting parameters and drill bit types on drilling outcomes. While Nomex® offers many advantages, difficult chip evacuation during drilling of aramid fiber composites can lead to surface defects and delamination. The research aims to explore how drilling parameters—such as spindle speed, feed rate—and four distinct drill bit types affect drilling performance. The analysis encompasses factors such as thrust force, torque, and surface roughness, studied under different drilling conditions and with various drill bit types. Moreover, the research assesses peeling and push-out delamination factors to gain insights into drill bit and coating characteristics. An examination of burr and chipping further enhances the comprehension of drilling performance. To determine the most effective drilling conditions, the study employs multi-response optimization. The optimal drilling performance is achieved with a combination of a 0.1 mm/rev feed rate, 1402.82 r/min spindle speed, and HSS-TiN drill type. This configuration successfully integrates responses, resulting in a composite desirability value of 0.95.