Flute Shape Research Articles

Effect of cutting flute design features on primary stability of immediate implant placement and restoration: a dynamic experimental analysis.

Self-tapping implants with self-cutting flutes may influence primary stability, especially for the immediate implant placement and restoration protocol in which implants are affixed to the bone in the apical portion. Screw geometry differs between brands, and the effect of apical design on its clinical outcomes remains unclear. This study is aimed at investigating the influence of cutting flute shape (spiral, straight, and without flute) on primary stability by using a dynamic experimental test. Six types of dental implants were designed using computer-aided design and computer-aided manufacturing technology, consisting of three types of cutting flute shapes along with two types of screw features. A dynamic mechanical test was performed using a cyclic loading scheme. The mechanical behaviors of resistance to lateral load (RLL), maximum force, and energy dissipation were compared between groups. In the dynamic test, implants without cutting flute also exhibited higher values in RLL, maximum force, and energy dissipation. The aggressive thread implant with straight flute displayed higher RLL and had a significantly higher values in RLL (p = 0.033) at the threshold point of bone-implant interface breakdown. The implants without cutting flutes exhibited higher primary stability. Straight flute design would improve RLL for aggressive thread implant.

An analytical study on nano-alumina modified concrete in-filled lightgauge steel fluted columns

Cold-formed steel sections are widely practiced cutting-edge of steel sections. A wide range of advantages prevails over the functioning of structural elements while cold-formed steel is been used along with the concrete in combination. Cold-formed steel in-filled columns filled with concrete have gained significance in the construction industry in recent times. Columns are built to withstand most of the axial load by the use of a thin-walled cold-formed steel tube by encasing the concrete. Far-reaching research regarding the behaviour, stress and strain characteristics of the columns using Cold-formed steel in-filled columns and the columns are stiffened using flutes which are provided along the length of the column as an integral part of the section of the column. The so-provided flutes will be triangular and rectangular in shape across the cross-section of columns. In this study, the behaviour of eighteen specimens with various types of flutes and thicknesses was examined. Analytical work was done using software for Finite Element Analysis. In this investigation, three cases with three, four, and five flutes each with a steel sheet thickness of one millimetre were taken into consideration. By the analytical investigation, the behavioural patterns of Cold-formed steel in-filled columns with flutes were carried out. From the analytical investigation implies that the load-bearing capacity of columns and the flute shape are directly related to the number of flutes in columns has an influential effect on resistance to higher loads.

Optimal design of helical flute of irregular tooth end milling cutter based on particle swarm optimization algorithm

Due to the variable pitch angle and helix angle of the irregular tooth end milling cutter, the mass of the integral end milling cutter is eccentric, and the high stability and precision design of the irregular tooth end milling cutter is still a challenge. Aiming at the influence of dynamic balance of irregular tooth end milling cutter which can not be ignored in high-speed milling, the parameterized design of radial section of irregular tooth end milling cutter was carried out. Based on the space transformation law of the centroid of helical flute, a new method for calculating the centroid coordinate of end milling cutter was put forward, and a general mathematical model of eccentricity of integral end milling cutter was given. It was proved that this model could accurately calculate the centroid position and eccentricity of the end milling cutter. The influence of pitch difference angle and helix difference angle on eccentricity of end milling cutter was studied and analyzed. The particle swarm optimization (PSO) algorithm was creatively applied to optimize the helical flute shape of the end milling cutter, the curvature radius of helical flute curve is optimized, so that the centroid coordinate is infinitely close to the origin of coordinate. The number of iterations was set to 200. In the 32nd iteration, the result approached to infinitesimal, the final function converged, and obtained the groove curvature radius of the milling cuter with the smallest eccentricity. The optimized eccentricity of the end milling cutter is infinitesimal, which can make the vibration damping performance of the end milling cutter be fully developed. On the basis of ensuring the same cutting performance, the cutting tool unbalance was effectively reduced and the dynamic performance of milling cutter was further improved.

Finite Element Simulation of the Flat Crush Behavior of Corrugated Packages

Corrugated paperboards are used for packaging because of their high strength-to-weight ratio, recyclability, and biodegradability. Corrugated paperboard consists of a liner and a corrugated medium and has an orthotropic sandwich structure with unique characteristics for each direction owing to its flute shape. In this study, finite element analysis (FEA) was performed on the flat crush behavior of the corrugated paperboard based on the flute type. The stress-strain (SS) curve and shape change of the flute were analyzed during the flat compression. In addition, it was compared with the FEA results through various experiments. The restraints and boundary conditions applied during FEA were used to properly describe the conditions during the experiment. Specifically, the horizontal translation motion of the top and bottom surfaces of the modeled test specimen was constrained during FEA to correspond to the effect of sandpaper attached to the upper and lower plates of the testing machine. This was done to prevent the specimen from sliding in one direction during the flat crush test. The change in the flute shape of the corrugated paperboard by flute type analyzed through experiments and FEA was very similar; although there was a difference in the absolute value between the two methods of the SS curve, the flute type exhibited a similar trend. Therefore, a qualitative comparative study on the flat crush behavior by flute type was possible with the FEA method, as in this study. Further studies on the material properties of the corrugated paperboard components and the modeling methods of the corrugated paperboard will enable the FEA-based simulation technique to be an alternative tool that can replace the flat crush test.

Self-optimizing process planning for helical flute grinding

Grinding of helical flutes is an important step in the process chain of cylindrical tool manufacturing. The grinding process defines the dynamic performance of the manufactured tool. Moreover, the surface quality and flute shape are primarily determined. For this reason, finding optimum process parameters is essential, especially in process planning of individual tools. In the industry, manual experiments are carried out for the machine set up. This leads to high costs due to machine hours, labor and material costs. This paper presents a self-optimizing and adaptable process planning method to reduce costs for process planning and improve the process result. The developed method allows to identify optimum cutting speed and feed with respect to economic efficiency and quality for new tools without additional machining experiments. Geometric-kinematical cutting simulations in combination with empirical models are used to predict the process outcome. The empirical models are derived from machine learning and improved automatically with an increase of process data. Applying the presented method in a case study, the machining time could be reduced by up to 38.1% and the core diameter deviation by up to 73.7%. Moreover, it is shown that the presented methods allow a continuous improvement of the process models.

A technique to quantify morphological damage of the flute profile in the midplane of corrugated fibreboard

This research presents a technique to quantify morphological damage to flutes in corrugated fibreboard (CFB). The method involves laser cutting thin samples and analysing digital images of the flute profiles. The surface profiles of creased CFB before and after laser cutting were measured using fringe projection and showed that the sample preparation does not significantly affect the flute profile. After imaging the laser cut samples, skeleton analysis was used to derive a digitised profile of the flute shape. To characterise the level of damage to the flute profile, a similarity factor (SF) was introduced to quantify the relative difference between test sample and reference flute profiles. Validation of this analysis technique was done by generating known images of flute profile with variations that include distortions that could occur to CFB. These images were then fed into the skeleton analysis, and the results were compared with the original profile. This comparison showed good agreement between the initial and skeleton‐analysed flutes. A demonstration of the skeleton analysis on purposefully damaged actual CFB flute profiles shows that the SF reduces as the level of crushing increases, showing that the technique could be used to enumerate morphological damage to CFB during manufacture, conversion, and use.

Nanowire formation is preceded by nanotube growth in templated electrodeposition of cobalt hybrid nanostructures

Cobalt fluted nanowires, novel nanostructures with a diameter of 200 nm consisting of a solid nanowire base and a thin, nanotubular flute shape, were grown in track-etched polycarbonate membranes via templated electrodeposition. The structures were characterized electrochemically via cyclic voltammetry, chronoamperometry, and charge stripping, and structurally via scanning electron microscopy, transmission electron microscopy, and focused ion beam cross-sectioning. Electrochemical and structural analysis reveals details of their deposition kinetics, structure, and morphology, and indicate possible mechanisms for their formation and control. These unique structures provide inspiration for an array of possible applications in electronics, photonics, and other fields.

Modeling, simulation and manufacturing of drill flutes

The designing of twist drill flutes (as well as that of end mills and of some combined tools) cannot be separated from the way they are manufactured. The aim of this paper is to present an intuitive direct method for modelling, simulation and manufacturing of the drill flutes with different shapes using conical grinding wheels with standardized shapes. The mathematical approach is described, which enables us to determine the flute profile in a section perpendicular to its axis as well as the manufacturing parameters. The grinding wheel has an initial position with respect to the cylindrical work piece, which is described using four parameters (Denavit Hartenberg parameters). We have presented algorithms in pseudocode that produce the flute shape and that compute the optimum parameters of the wheel position in the manufacturing process. Subsequently, a software application based on the aforementioned model is able to create visualizations of the flute shape. The analysis of the flute shape has enabled us to understand the influence of the geometrical parameters and the position of the grinding wheel on the resulting product in the grinding process. The order in which these parameters are to be set is also specified. We have built atlases of maps presenting the influence of the geometrical parameters and the position of the grinding wheel in the grinding process upon the shape of the flute. The validity of the method is proven by the agreement of the computed values with the input and output data produced by experiment. The proposed method allows helical flutes to be generated solely by using cylindrical and conical grinding wheels of standard shapes.

Pentameric viral ion channels: from structure to function

Pentameric viral ion channels: from structure to function Wahyu Surya, Yan Li, Jaume Torres School of Biological Sciences, Nanyang Technological University, Singapore Abstract: A family of small polypeptides in many virus types associate to form oligomers and have channel activity. These proteins have been referred to as viroporins or virochannels and are increasingly recognized as important virulence factors and potential drug targets. In this review, we focus on two of the viroporins that have been studied in more detail from a structural and functional point of view. One is the 76-residue envelope (E) protein found in coronaviruses (CoVs) that causes the severe acute respiratory syndrome (SARS). The other is the 65-residue small hydrophobic (SH) protein found in a paramyxovirus, the respiratory syncytial virus (RSV). RSV SH and SARS-CoV E proteins are short polypeptides with a single transmembrane domain. In both cases, the presence of the viroporin has a protective effect on cells, preventing early apoptosis, but it leads to increased virulence in infected animal models. Both viroporins form homopentameric oligomers that show channel activity with no or low selectivity. The role of channel activity is still unclear, but associations have been made to facilitation of the egress of the virus by modification of the secretory pathway, and contributions to inflammation. SARS-CoV E protein has a cytoplasmically oriented C-terminus and a lumenal N-terminus, whereas the opposite orientation is found in RSV SH protein. Despite this opposite topology, nuclear magnetic resonance (NMR)-based structural models of these two channels show a similar champagne flute shape, with the wider opening facing the cytoplasmic side. Good channel inhibitors are lacking, but those found seem to have a preference for the narrow end of the channel. Availability of good inhibitors will help reveal the specific role of these channels in the life cycle of these viruses. Keywords: respiratory syncytial virus, severe acute respiratory syndrome, small hydrophobic protein, envelope protein, channel structure

A New and Accurate Mathematical Model for Computer Numerically Controlled Programming of 4Y1 Wheels in 2½-Axis Flute Grinding of Cylindrical End-Mills

Solid carbide cylindrical end-mills are widely used in machining, and their helical flutes are crucial to their cutting performance. In industry, the flute is simply defined with four key parameters: the helical angle, the radial rake angle, the fluting angle, and the core radius, which are specified in an end-mill design. The flute shape is not fully defined, while it is often generated by a 1A1 or 1V1 diamond wheel in 2½-axis computer numerically controlled (CNC) grinding. Unfortunately, the two simple wheels cannot make largely different flute shapes, preventing further improvement of the end-mills. Although no research result on how the flute geometry affects the end-mill cutting attribute has come into public yet, it is now necessary to employ more complicated wheels to grind flutes with the specified parameter values but much different flute shapes. For this purpose, the 4Y1 diamond wheel is employed in this work. However, the commercial tool grinding software cannot determine the dimensions and the set-up angle for the 4Y1 wheel. To address this problem, a new mathematical model of the flute parameters in terms of the dimensions and the set-up angle of the 4Y1 wheel is formulated, thus, the 4Y1 wheel can be used in flute grinding. This work lays a foundation of using complex wheels to grind flutes with more shapes in order to improve the end-mill's cutting ability.

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.

The effects of flute shape and thread profile on the insertion torque and primary stability of dental implants

Easy insertion of the implant and stable bone purchase is essential for an ideal dental implantation. At the implant tip, the cutting flutes and conical profile are respectively designed to reduce insertion resistance and facilitate the initial insertion. However, the tapered tip might reduce the self-tapping and bone-purchasing abilities of the flutes and the tip threads. Using sawbone blocks as standard specimens, this study experimentally measures the insertion torque, holding power, and bending strength of eight varieties of implant (4 shapes×2 profiles). The bony contact, interfacial mechanism, and the altered shape of the flutes, at different section planes, are used to explain the experimental results. The results reveal that the bone-implant gaps at the tip region significantly suppress both the self-tapping and bone-purchasing abilities of the flutes and the tip threads. This makes initial insertion of the conical implant easier. However, the conical implant eventually requires a higher insertion torque and holding power, due to tighter bony contact, at the tail threads. The bowl-fluted design has the least flute space to store the squeezed bone chips, so both insertion torque and bending strength are significantly higher. For the conical group, the holding powers of three flute designs are nearly comparable. Overall, the conical implant with bowl flutes is the optimal design, with a lower resistance to initial insertion and higher stability, for final instrumentation.

Research on Specific Structural Parameters of Modified-Tooth Tap for Titanium Alloy TC4

With Third Wave AdvantEdge FEM software, an equivalent finite element model in tapping has been built, making a simulation study of the chip curling of titanium alloy TC4 and analyzing the influnce of a tap hook angle and chip flute shape on chip curling. Based on the simulation study above, the modified-tooth taps made of high-speed steel W9, which have two types of chip flute shape with a chamfer angle of 7°30´and respectively, were developed and the comparative tests of tapping TC4 have been done. The results indicates that the chip removal effects in hand tapping with the standard flute shape and respectively are on the same level, but the tapping torque has become smaller and more effective to a chamfer angle of .

THEORETICAL INVESTIGATION OF THE EFFECT OF FLUTE PROFILE ON FLAT CRUSH STRENGTH OF CORRUGATED BOARD

Curved beam theory is used to investigate the buckling failure of corrugated boards. The corresponding governing differential equation is developed from the geometry of the flute and the equilibrium equations. The resulting differential equation is highly nonlinear for which an iterative algorithm is presented. The method can be used to study buckling of the CB and measure the flat crush test (FCT) of a variety of flute shapes. It is shown that for a given amount of medium, there exists an optimum flute shape that gives the highest FCT. Because a low FCT means poor performance in printing operations and cushioning, the method can help manufacturers to select appropriate board. The corresponding algorithm and examples are presented.

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

Applying the finite element method to drill design based on drill deformations

The design of the twist drill with special cross-sectional shape using the finite element method based upon drill deformations was presented in this paper. In order to improve the unfavorable distribution of the total orthogonal rake angle along the primary cutting edge of a thick web drill, a thick web drill with curved primary cutting edges was devised. The profile of the curved primary cutting edge was mathematically determined by changing the distribution of the tool orthogonal rake angle along the primary cutting edge. A three-dimensional finite element analysis based upon the drill deformations was applied to obtain the “secondary” flute shape and to specify the web thickness, the helix angle, and the flute length. The effect of these geometric [arameters on drill deformations was also investigated. Experiments were conducted to evaluate the drill's cutting performance. Experimental results indicated that the thick web drill with curved primary cutting edges was effective in reducing the thrust force, the torque, and the tool wear, a strength that definitely provided a better cutting drill and longer tool life for drilling the JIS S50C heat-treated steel.

The dynamic geometry of a twist drill point

A twist drill is characterized by complex geometry which is a direct function of the sharpening method used. This geometry has been studied by several investigators attempting to understand the cutting mechanism of the drill point. Each cutting lip has been considered analogous to a single-edge cutting tool in which the normal rake angle varies from positive at the outerside to negative at the innerside. Optimum performance is achievable using straight cutting lips occurring only in certain combinations of flute shape and point angle. The chisel edge in a conventionally ground drill has no true point. This is mainly responsible for geometric errors in drilling. In a double plane sharpened drill point, a well defined chisel edge with four faces is produced. This point possesses a self centering action which facilitates drilling operations. The contribution of feed velocity to cutting velocity cannot be neglected especially at the center where they are equal. This paper studies the working geometry of a double plane sharpened drill point, taking the effect of feed velocity into consideration. The effect of feed can be neglected at the cutting lips without a remarkable error, but cannot be neglected at the central zone.

Cutting performance of thick web drills with curved primary cutting edges

In order to improve the cutting performance of drills, a thick web drill with curved primary cutting edges was devised. The curved primary cutting edge was mathematically determined by changing the distribution of the tool orthogonal rake angle along the primary cutting edge. A three-dimensional finite element analysis based on the torsional rigidity of the drill was applied to obtain the “secondary” flute shape of the drill with curved primary cutting edges and to specify the web thickness. Experiments were conducted to evaluate the drill's cutting performance. Compared with conventional twist drills of different web thicknesses, the thick web drill with curved primary cutting edges shows greater effectiveness in reducing the thrust force, the torque, and the tool wear, thus providing a better cutting ability and a longer tool life.