Flute Length Research Articles

Effect of cutting flute geometry of orthodontic miniscrew on cortical bone microdamage and primary stability using a human bone analog

AbstractBackgroundAlthough orthodontic miniscrews were developed to provide reliable anchorage against orthodontic traction forces, they have pervasive low stability problems. Cutting flute geometry of the screw is considered to be a key factor; however, it has not been fully investigated. Therefore, the objective of our study is to evaluate the effect of cutting flute geometry on cortical bone microdamage.Materials and methodsHuman bone analogs, 1.0 mm thick, were prepared alongside custom‐made Ti6Al4V screws. These screws, with no flutes or modified flute geometries, came in lengths of 1.2, 2.4, and 5.0 mm, each with rake angles of 0° and 20°. Each screw was inserted into a bone sample and removed while measuring the maximum insertion torque (MIT) and the maximum removal torque (MRT). The bone microdamage was evaluated using cross‐sectional surface images of human bone analogs.ResultsMRT was significantly different in all pairwise comparisons among the three flute‐length groups in each rake angle, and the 5.0‐mm‐length groups demonstrated the lowest values. Similar tendencies were found in MIT and the bone microdamage, although significant differences were not observed in all the pairwise comparisons in the flute‐length groups in each rake angle. Interestingly, the two rake angle groups in each flute‐length exhibited significant differences in MIT and the bone microdamage, but not in MRT.ConclusionFrom our investigation using custom‐made screws and human bone analog, cortical bone microdamage is affected by both flute geometries, whereas primary stability is affected by only the flute length.

Procena karakteristika obrade i habanja alata tokom bušenja ugljenika / aluminijum-aluminijum

In the past few decades, fibre metal laminate (FML) machining has been facing critical challenges in quality control and tool wear monitoring due to the material's intrinsic heterogeneity and abrasiveness. Different drill tools have been used to investigate the effect of process parameters on machining performances. Composite holes and tool wear was studied for drilling forces and surface roughness. An emphasis was made on examining the tool morphologies and wear processes that influence the drilling of CARALL composites. The drilling responses obtained from both the drill bits were optimized using a decision-making approach viz; Combined Compromise Solution Analysis (CoCoSo). The SEM investigation of the machined samples was used to examine the hole quality and surface finish. A lower point angle drill with a longer chip flute length produced the best results for drilling CARALL composites up to a specific point with minimum flank wear and chip adhesion.

Comparing Clovis and Folsom fluting via scaling analysis

AbstractThis study examines the fluting of two well‐known Late Pleistocene fluted point types in North America: Clovis and Folsom. Using scaling analyses, we assess the changing relationship between flute length and point length in a large sample of each type. Researchers use scaling to investigate the physical constraints of an object and determine how its dimensions change with size. We compare the strength and consistency of the scaling relationships between the older Clovis and the younger Folsom with the aim of shedding light on scaling differences, if any, over their temporal span. Our results show that there is a significant difference in the relationship of fluting length to point length between these types. In Folsom point manufacture, flute length increases nearly twice as fast with increasing point length than in Clovis. Importantly, the scaling of flute length to point length relationship is isometric (linear) in the Folsom sample, whereas it is allometric (sublinear) in the Clovis sample. In other words, Folsom flintknappers maintained a constant ratio of flute length to point length. Clovis flintknappers were less concerned about maintaining this ratio. We attribute this difference to a potentially increasing, or changing, functional role of fluting in Folsom.

Advantages of Injection Mold with Hybrid Process of Metal Powder Bed Fusion and Subtractive Process

This paper focuses on the hybrid process combining metal additive manufacturing (AM) and subtractive processing developed for application to injection molds. The basic concept is a combination of laser powder bed fusion of metal powder and subtractive processing. This process is characterized by alternating buildup and milling processes. Even the inner surface of deep grooves, which conventionally required electrical discharge machining, can be machined with small-diameter tools with a short flute length. Therefore, molds with complex shapes that previously required electrical discharge machining can be manufactured in a single process. Moreover, a dimensional accuracy and surface roughness of levels equal to those achieved by machining with the machining center can be ensured. In the hybrid process, it is necessary to minimize the surplus solidified area (which is the area milled by the small-diameter tool). Therefore, the formation mechanism of the surplus solidified region is verified. It is shown that the power distribution of the laser beam significantly affects the size (width and depth) and density distribution of the excessively solidified region. In addition, the effective value of metal AM mold is introduced. The 3D cooling circuit improves the efficiency of the injection molding process. If the temperature balance between the cavity side and core side is achieved, the distortion of the molded product would be suppressed. If the cooling effect is promoted, the molding cycle would be shortened substantially. Second, the effect of the gas vent function by a permeable structure is explained through actual examples. The effect of the gas vent function by the permeable structure is explained. It is indicated that stable molding can be achieved. In addition, the appearance defects of molded products can be reduced when the air inside the cavity is exhausted sufficiently from the mold through the permeable structure.

Mathematical modeling and multiresponse optimization to reduce surface roughness and adhesion in Al 5083 H116 alloys used in ammunition propulsion actuators

PurposeThis study aims to obtain the lowest surface roughness (Ra) and drill bit adhesion values (AV) depending on the change in control factors (cutting speed-Vc, feed rate-f and drill bit-D) during drilling of the Al 5083 H116 alloy. Low roughness values increase the fatigue strength of the final part and affect tribological properties such as lubrication and friction. In the machining of ductile materials, the AV increases the Ra value and negatively affects the tool life.Design/methodology/approachDrilling tests were conducted using Taguchi L16 orthogonal array. The experimental measurement findings for Ra and AV were adjusted utilizing the Grey Relational Analysis (GRA), the Response Surface Method (RSM) and Artificial Neural Networks (ANN) to generate prediction values. SEM detected drill-tip adhesions and chip morphology and they were analyzed by EDX.FindingsRa and AV increased as the f increased. Vc affects AV; 86.04% f on Ra and 54.71% Vc on AV were the most effective control parameters. After optimizing Ra and AV using GRA, the f is the most effective control factor. Vc: 120 m/min, f: 0.025 mm/rev and D2 were optimal. ANN predicted with Ra 99.6% and AV 99.8% accurately. Mathematical models are obtained with RSM. The increase in f increased AV, which had a negative effect on Ra, whereas the increase in Vc decreased the adhesion tendency. With the D1 drill bit with the highest flute length, a relatively lower Ra was measured, as it facilitates chip evacuation. In addition, the high correlations of the mathematical models obtained indicate that the models can be used safely.Originality/valueThe novelty of this study is to determine the optimum drilling parameters with GRA and ANN for drilling the necessary holes for the assembly of ammunition wing propulsion systems, especially those produced with Al 5083 H116 alloy, with rivets and bolts.

Mathematical modeling and experimental studies on axial drilling load for rotary ultrasonic drilling of C/SiC composites

Ceramic matrix composites of type C/SiC have great potential in space applications because of their superior properties such as low density, high wear resistance, and high-temperature resistance. However, due to their heterogeneous, anisotropic, and unstable thermal properties, the machining is still challenging to achieve desired efficiency and quality. For advanced materials, rotary ultrasonic machining (RUM) is considered as a highly efficient technology. Predicting mechanical load in RUM can help to optimize input variables and reduce processing defects in composites. In this research, a mathematical axial drilling load (force and torque) model has been developed based on the indentation fracture theory of material removal mechanism considering penetration trajectory and energy conservation theorem for rotary ultrasonic drilling (RUD) of C/SiC. Experiments were conducted on C/SiC composites to validate the model, and experimental results agreed well with model predictions with less than 14% (force) and 10% (torque) error. Therefore, this theoretical model can be effectively applied to predict axial drilling load during RUD of C/SiC. The relationships of axial drilling force and torque with machining process parameters, including spindle speed, feed rate, and ultrasonic power, were investigated. A specific range of experiments was carried out to demonstrate the benefit of ultrasonic vibration in RUD over conventional drilling (CD) on mechanical load for a designed drilling tool. It was noticed that RUD outperformed CD with a maximum of 38.11% and 34.30% in axial drilling force and torque reduction, respectively. The influence of drilling tool flute length on drilling performance was also elucidated based on a set of experiments using several designed drilling tools.

Examination of the influence of flute length on the self‐tapping ability of reverse taper body shift implants in extraction sockets

Examination of the influence of flute length on the self‐tapping ability of reverse taper body shift implants in extraction sockets

Fluted hafted bifaces in the Northeast and Clovis: A North America wide perspective using image analysis

The degree of variability present in fluted hafted biface morphology across North America is often debated. In this work I use a series of ratio scale linear measurements to examine variability in Early Paleoindian period fluted hafted bifaces from seven different Culture Areas across North America. Instead of analysing the actual artifacts, measurements are taken on high resolution images of the hafted bifaces. I find that the Early Paleoindian period fluted hafted bifaces from the Northeast are significantly different from those found elsewhere in terms of base depth and flute length. These differences have wide reaching implications for large scale studies of Early Paleoindian hafted bifaces.

Flute and Shank Dimensions of Reciprocating Instruments before and after Simulated Root Canal shaping

This study analyzed the effect of the dimensions of the flute and shank in the first 4 mm of instrument tips on the deformation and dimensional changes of reciprocating instruments after root canal shaping (RCS). The reciprocating instruments used were Reciproc® R25, R40, and R50; WaveOne® Small, Primary, and Large; and Unicone® #20, #25, and #40. Scanning electron microscopy images of the first 4 mm of the tip were acquired at 30× magnification before and after simulated curved root canals were shaped. Each instrument was used only once. The images were transferred to the AxioVision® software to measure the flute area (μm2), shank area (μm2), flute length (μm), and cross-sectional diameter (μm). Student's t test for paired samples was used to compare differences before and after RCS, and analysis of variance followed by the Tukey test, to compare differences between instruments of similar sizes. The instruments were classified according to deformations after RCS. Reciproc® instruments had larger flutes and smaller shanks. The Reciproc® R40 had significant differences in cross-sectional diameter at 0.5 mm from the tip. Reciproc® had no plastic deformations. Unicone® #20 instruments had significant differences in cross-sectional diameter at 1.5 and 3.0 mm from the tip, and #25 instruments had differences at 1.5 and 3.0 mm and in length of the second and third flutes. One #20 and three #40 instruments had plastic deformations. The differences in length of the first and fourth flutes of WaveOne® Primary and in cross-sectional diameter at 2.0 mm from the tip of WaveOne® Large were significant. Two of three WaveOne® Large instruments had plastic deformations. Reciproc® instruments had greater flute areas and lengths and smaller shanks than Unicone® and WaveOne® instruments of similar sizes. Reciproc® instruments had a greater flute-to-shank ratio. WaveOne® instruments had the lowest flute-to-shank ratio. Unicone® instruments had the most plastic deformations. Instruments with larger flutes and smaller shanks had fewer plastic deformations after curved RCS. The knowledge of mechanical behavior before choosing the endodontic instrument may avoid fracture, regardless of the clinical condition, and it is essential to the success of root canal treatment.

工具溝長間表面性状のアルミニウム合金切削性能に及ぼす影響

工具溝長間表面性状のアルミニウム合金切削性能に及ぼす影響

データマイニングを用いたプリント基板用マイクロドリルカタログの条件設定に関する考察

In this research, we suggest the catalog-mining method which means applying data-mining method to micro-drill catalogs. -We regard the catalogs as mine which includes the knowledge of micro-drilling plenty. - Data-mining method is one of the analytical methods to discover the valuable information from a mass of data and commonly used in the undeveloped field of study. In this paper, we focused on a relationship between diameter and flute length of micro-drill and classified them. By using the classification, we analyzed cutting conditions for catalogs of micro-drill. In addition, we introduced catalogs of multi micro-drill which cut alloyed steel. The result shows that catalogs have different cutting condition in classifying particular flute length. And micro-drills for PCBs which have small diameter and multi micro-drills for alloyed steel have same tendency of cutting conditions.

The Research of Impact Ball End Mills Geometric Parameters on Processing Stable Region

In this paper, modal analysis of ball end mills is modeled by finite element to work out natural frequency and chatter model in tooling system and to calculate the limit curve of stability in single degree freedom system. The effect of cutter flute length and cutter tooth number on maching stability area is also discussed. The results of research show that steady critical cutting depth of milling system declines while the cutter flute length increases, but the trend is not linear, which shows increase partly. An engineering optimization design is made on milling cutter geometrical parameters based on this conclusion.

Optimization of seed flow evenness of fluted rolls used in seed drills by Taguchi method

The purpose of this study is to optimize the seed flow evenness in seed drills of the fluted feed rolls; wheat was used in the experiments. Experiments were conducted according to Taguchi optimization method and L9 orthogonal array is selected. Flute shape (asymmetric, trapezoid and semicircular), flute lengths (5, 10 and 15 mm), and axis rotational speed (25, 30, and 35 min-1), and coefficient of variation used to measure the flow evenness were chosen as independent variables and dependent variable, respectively. According to the results of variance analysis, the order of the importance of factors affecting to the flow evenness are found to be flute length, axis rotation speed and flute shape, respectively. Minimum coefficient of variation was obtained at the flute shape of trapezoid, flute length of 15 mm and axis rotation speed of 35 min-1. At the optimum conditions, coefficient of variation for wheat was obtained as 2.87. As a result of this study, it was shown that Taguchi method is a significant tool for such optimization problems and can be effectively used in any experimental studies on agricultural subjects. Key words: Taguchi method, seed drill, fluted roll, flute shape, flow evenness, CV.

Novel micro deep drilling using micro long flat drill with ultrasonic vibration

Abstract This paper highlights the development of micro long flat drills with nominal diameter and flute length of 20 μm and 200 μm, respectively, by precision grinding. Furthermore, it also covers the evaluation of the developed micro long flat drill in micro deep drilling. Micro long flat drills were made of ultra-fine grained cemented carbide containing WC particles with an average particle diameter of 90 nm. First, the study focused on establishing the optimal web thickness of micro long flat drill showing the best performance in micro deep drilling. In drilling experiment, observation was conducted with the aim of finding the best conditions and method of micro deep drilling into both duralumin and stainless steel workpieces. This observation included the applications of ultrasonic vibration (USV) and step feeding method. The study proved that there was an optimum web thickness resulting in the best drilling performance. Furthermore, the application of USV during drilling could lead to a longer tool life significantly. However, there was no improvement of drilling performance in drilling with step feeding.

Research of Cutter Geometric Parameter Effect on Machining Stability Area in High Speed Milling Process

In this paper, modal analysis of ball end mills is modeled by finite element to work out natural frequency and chatter model in tooling system and to calculate the limit curve of stability in single degree freedom system. The effect of cutter flute length and cutter tooth number on limit curve of stability in single degree freedom system is also discussed. The research results show that steady critical cutting depth of milling system declines while the cutter flute length increases, but the trend is not linear, which shows increase partly. An engineering optimization design is made on milling cutter geometrical parameters based on this conclusion.

Influence of machining parameters on microdrill performance

There is an increasing interest in microdrilling of metallic and other miniaturised components. Drill breakage is the most prevalent problem with microdrill that possesses high length-to-diameter ratio. In this paper, finite element modelling approach is used to determine the buckling load of a microdrill while drilling metallic components. The influence of variation in flute length, diameter, helix angle and lip angle on buckling load during machining of metallic components is studied. Empirical loading equation based on the material hardness, feed and diameter of the microdrill is also used to estimate the loading condition during microdrilling operation. Results are in agreement with the buckling loads predicted by proposed finite element model. In the present work emphasis is made on estimating the critical feed and the speed based on modal analysis while machining various materials. Tool failure can be avoided by maintaining the machining conditions within these critical operating parameters.

Development of a micro drill bit with a high aspect ratio

PurposeThe purpose of this paper is to present key points relating to the development of micro drill bits with high aspect ratios and to provide a solution for high aspect ratio hole drilling.Design/methodology/approachBased on the analysis of challenges in high aspect ratio hole drilling, key points for the development of micro drills bit with high aspect ratio are discussed. A design example of a micro drill bit with 0.3 mm diameter and a 7.2 mm flute length is presented. Experiments are conducted to verify the performance of the developed micro drill bit.FindingsHelix angle, web thickness and flute land ratio are three key parameters that significantly influence the behaviour of micro drill bits with high aspect ratios. Large helix angle, web thickness and flute land ratio are beneficial in terms of improving the performance of high aspect ratio micro drill bits. Step drilling is essential to prevent drill breakage and to ensure smooth debris evacuation. Meanwhile, proper steps and drilling parameters are of great importance to complete high aspect ratio hole drilling.Originality/valueThe paper highlights key points relating to the development of micro drill bits with high aspect ratios that can provide a satisfactory solution for high aspect ratio micro drill bit design.

Design Improvement and Failure Reduction of Endodontic Files through Finite Element Analysis: Application to V-Taper File Designs

Introduction Torsional stiffness and bending flexibility are essential characteristics as far as the performance and safety of the endodontic files are concerned. Inadequacy in addressing these requirements in file design leads to increased risk of file failure. The stiffness and flexibility of the endodontic file are greatly dependent on its geometric design. The aim of this study was to evaluate the influence of geometric features on the mechanical performance of endodontic files through numerical simulations. Methods Finite element models of V-Taper file were developed, and the mechanical behavior of the file under bending and torsional loads was simulated. The influence of helix angle, taper, and flute length was evaluated through parametric studies. Results In the helix angle range between 5 and 40 degrees, the bending flexibility and torsional stiffness both improve with increasing helix angle. The torsional stiffness increases with increasing taper or decreasing flute length, accompanied by a decrease in bending flexibility. Changing the flute length alone does not result in a change in the stress profile in the tip section. The elastic limit of V-Taper file tip section was estimated in the form of transverse deflection and angular deformation in bending and in torsion, respectively. Conclusions The influence of helix angle, taper, and flute length on the bending flexibility and torsional stiffness of V-Taper files was quantitatively assessed through parametric studies with finite element method. The elastic limit of the V-Taper file tip section was estimated. A design methodology for achieving improved mechanical performances was proposed.

Effect of cutting flute length and shape on insertion and removal torque of orthodontic mini-implants

Effect of cutting flute length and shape on insertion and removal torque of orthodontic mini-implants

Parametric studies on buckling loads and critical speeds of microdrill bits

Transverse bending vibrations of the spinning microdrill bit subjected to a compressive axial load are developed based on the Timoshenko beam theory. The system equations of motion are discretized into the form of time-dependent ordinary differential equations by the finite element method. Two types of eigenvalue problems are formulated and utilized to study the effects of the drill helix angle, flute length and diameter on the buckling load and critical speed of microdrill bits with different supported ends. Equivalent formulae similar to those of untwisted Euler beams are established to predict critical buckling loads and critical speeds for microdrills and provide results with sufficient accuracy. The effect of rotational speed on the buckling load, and the influence of thrust force on critical speed are also investigated. A Galef-type equation associated with critical speed, thrust force and buckling load is formulated.