Cut Shape Research Articles

A novel power skiving method using the common shaper cutter

To reduce the skiving cutter cost and make the power skiving more flexible, a novel skiving method is proposed by optimizing the machine setting parameters using a common shaper cutter. First, the mathematical model of power skiving for working an involute cylinder gear was established based on the engagement principle of crossed helical gear. Then, a common shaper cutter profile deviations caused by the cutting angles was derived. By analyzing the relationship between the tooth deviations and the machine setting parameters, a correction method for both flanks power skiving is proposed to correct the machine setting parameter using the principle of linear superposition and the linear regression method. The validity of the correction method for power skiving is numerically demonstrated as working an involute cylinder gear for example. The results show that power skiving process can be achieve by the common shaper cutter and makes the latest technology more flexible and economic.

A Three-Dimensional-Printed Home-Based Flexible Nasopharyngeal Explorer With Diamond Cuts1

A Three-Dimensional-Printed Home-Based Flexible Nasopharyngeal Explorer With Diamond Cuts1

뽕나무 수령 및 오디 생산성, 오디균핵병 및 가격비교 연구

Though mulberry fruit is known to a by-product that was produced from mulberry tree after harvesting leaves for silkworm rearing, as a yield and consumption of mulberry fruit was increased, it has been fixing to a new income crop. But, a stable production of mulberry was issued on damage by the weather disaster, so it is requires that agricultural disaster insurance import. So, in this study as a basic research for a importation of agricultural disaster insurance, the cultivation of mulberry for the production of mulberry fruits, the shape of tree, the number of a bearing fruit from each cultivar, the occurrence of mulberry fruit sclerotic disease, and a yield and the market price of mulberry fruits were investigated and that results obtained were as follows; The number of mulberry tree each 10a was abundant in Buan and Jeongeup region that cultivated a suitable cultivar on low cut shape, however, a large cultivated Gochang region was little. The number of a bearing fruit per 1m on the branch was highest in the variety of Cheongilppong at Gochang. Yield of mulberry fruits each 10a was Cheongilppong at Gochang, followed by Iksuppong at Sangju. Average sale price of the mulberry fruits was high in the order of Gwasang No. 2, Suwonppong, Iksuppong, and Cheongilppong.

Machining mechanism research of glass by discrete element method

The discrete element method (DEM) is applied to glass micromachining in this study. The indentating, cutting, micro milling process are simulated by the established DEM matching the main mechanical properties of glass in three sets of standard tests. Results show that the vertical damage depth is prevented from reaching the final machined surface in cutting process. Tool rake angle is the most remarkable factor influencing the chip deformation and cutting force. The final machined surface is determined by the minimum cutting thickness per edge. Different cutting thickness, cutter shape and spindle speed largely affect the mechanism of glass.

Experimental Study on Force of Stinger Cutter Breaking Rock

Singer PDC cutters of five different cone top diameters are designed and manufactured.On the basis of rock-breaking test with stinger PDC cutters, effects of significant factors on cutting forces are discussed, including cutting angle, cutter shape and rock hardness. The test results show that the stinger PDC cutters have the ability of drilling hard rock.The sharper the stinger PDC cutter is, the stronger the ability of drilling the formation will become.15°is an optimal front rake angle.

Improved Vlasov Antenna with Curved Cuts and Optimized Reflector Position and Shape

This paper presents a Vlasov antenna with curved cut shape and improved reflector position and geometry suitable for high power microwave applications. The curved shape of the proposed cut totally eliminates the sharp edges and angles present in Vlasov antennas with step and bevel cuts. Furthermore, with the proposed reflector configuration, the wave is radiated in the direction of the axis of the waveguide. A Vlasov antenna, designed for operation at 3 GHz, is used to compare the three cut types. An additional comparison is conducted to validate the concept of the enhanced reflector position, using the bevel-cut antenna and the improved cut. The proposed antenna results in increased antenna gain and in good performance in terms of sidelobe level and half-power beamwidth, with maximum radiation directed toward the axis of the waveguide center.

Geometrical model and tooth analysis of undulating face gear

A new gear set consisting of a planar noncircular gear and a specific face gear called undulating face gear is presented, which are able to transmit varying angular velocity. Based on the kinematics of planar noncircular pinion and rack, the formation mechanism of pitch curves of the undulating face gear is given, with the continuous transmission condition of the gear set discussed. Tooth surfaces of the undulating face gear are enveloped by the teeth of a shaper cutter when its pitch circle rolls on the pitch curve of the undulating face gear without sliding. According to the spatial meshing theory, the mathematical model of the face gear tooth surface is built. The phenomenon of tooth undercutting and tip-cutting of the face gear is investigated through three-dimensional machine design software to obtain its minimum inner radius and maximum outer radius. Furthermore, a computer program is developed to calculate the data of the face gear tooth surface and a motion simulation of the gear set without undercutting and tip-cutting is made, which is able to illustrate validity and correctness of the design theory.

Differential equation for tool wear

The wear topography of a cutting tool is considered in relation to the redistribution of the contact stress in frictional areas at the front and rear cutting surfaces. A differential equation is obtained for the tool wear. On that basis, the cutter shape is optimized so as to ensure uniform wear.

Decision Support System for Flame-Cutting Machines Scheduling

The article presents Decision Support System for time scheduling of work orders in operations producing heavy plate cut shapes. The IPO (Input – Process – Output) diagram was used to design the mental model of the system. The heart of the system is based on Generalized Assignment Problem and Buffer Management. The mental model was programmed in MS Excel by means of Visual Basic for Applications (VBA) macros.

Influence of Tool Inclination on Micro-Ball-End Milling of Quartz Glass

Glass is difficult to machine due to its susceptibility to brittle fracture during machining. Tool tilt angle can exert a remarkable effect on the surface finish of glass in micro-ball-end milling. On the basis of a theoretical analysis and simulation by three-dimensional discrete element method, an optimal mathematical model is constructed for tool inclination, which is governed by edge radius of ball-nose of end-mill and cutting thickness. Corresponding experiments are conducted for model verification. The results show that different cutting thicknesses, cutter shapes, and spindle speeds have a considerable influence on machining mechanics of glass.

Study on Machining Mechanism of Glass Using Discrete Element Method

The discrete element method (DEM) is applied to glass micromachining in this study. By three standard tests the discrete element model is established to match the main mechanical properties of glass. Then, indentating, cutting, micro milling process are simulated. Results show that the vertical damage depth is prevented from reaching the final machined surface in cutting process. Tool rake angle is the most remarkable factor influencing on the chip deformation and cutting force. The final machined surface is determined by the minimum cutting thickness per edge. Different cutting thickness, cutter shape and spindle speed largely effect on the mechanism of glass.

Study of optimal strategy and linkage-model for external non-circular helical gears shaping

As an efficient manufacturing method for gears, shaping technology developed for non-circular helical gears will greatly break through the dilemma of their applications; especially for those gears with part of pitch curves being concave, being not able to be hobbed. Two fundamental linkage-models for external non-circular helical gears were built based on the meshing theory of non-circular gears in this article. According to four linkage methods in plane and two kinds of additional rotation in vertical direction, eight shaping strategies and their practical linkage-models (1)–(8) were developed. Taking a three-order elliptic helical gear as an example, the kinematic characteristics of the eight practical linkage-models were analyzed, which reveals that equal arc-length of gear billet (models (3) and (4)) have the highest accuracy under a given efficiency. The dynamic characteristics of models (3) and (4) were analyzed, which shows that model (4) (equal arc-length of gear billet and additional rotation on shaper cutter) is better in performance, and is an optimal one. The optimal linkage-model was demonstrated to be valid by a virtual shaping, and be able to shape those non-circular helical gears with part of pitch curves being concave. Moreover, the accuracy among every gear tooth is uniform. The theory developed and the results of the virtual shaping were illustrated with a shaping experiment. The train of thought and the results will be useful for any external non-circular helical gears with free pitch curves.

Dense nuclei segmentation based on graph cut and convexity–concavity analysis

With the rapid advancement of 3D confocal imaging technology, more and more 3D cellular images will be available. However, robust and automatic extraction of nuclei shape may be hindered by a highly cluttered environment, as for example, in fly eye tissues. In this paper, we present a novel and efficient nuclei segmentation algorithm based on the combination of graph cut and convex shape assumption. The main characteristic of the algorithm is that it segments nuclei foreground using a graph-cut algorithm with our proposed new initialization method and splits overlapping or touching cell nuclei by simple convexity and concavity analysis. Experimental results show that the proposed algorithm can segment complicated nuclei clumps effectively in our fluorescent fruit fly eye images. Evaluation on a public hand-labelled 2D benchmark demonstrates substantial quantitative improvement over other methods. For example, the proposed method achieves a 3.2 Hausdorff distance decrease and a 1.8 decrease in the merged nuclei error per slice.

Fabrication of micro-dimpled surfaces through micro ball end milling

Industry and researchers have begun to shift their focus towards more sustainable and eco-friendly manufacturing processes in recent years. They have recognized the vital role of functional micro surfaces for a wide range of advanced applications to address this issue. By physically altering the surface structure of a material in micrometric scale, tribological, optical, fluidic properties and many other surface characteristics can be altered. Several researchers have reported that micro surface patterns can reduce friction between lubricated sliding surfaces, which in turn alleviate energy consumption and increase service life of components. Micro ball end milling is another viable technique for creating patterned surfaces, especially for metallic parts. By tilting the spindle and tool at an inclined angle, the spindle speed and feed rate can be adjusted so that the flutes of the cutter create periodic patterns in a workpiece surface. Machining is an efficient and versatile manufacturing technique, making the micro dimple machining technique an ideal method to fabricate dimpled surfaces. In this study, the fabricated surfaces are evaluated at a tribological level to illustrate their effectiveness at reducing friction. The development of efficient methods to produce micro patterns onto large surface areas can promote a sustainable future for a variety of novel products. The development of efficient surface pattern algorithms for generating different dimple geometries is also a focus; and, trends in cutting forces are identified by changing different machining parameters. Depth of cut and dimple shape, spacing and arrangement are crucial parameters, all of which factor into the performance of a functional surface. The results of this study strongly indicate micro dimple machining as an environmentally sustainable method of producing functional surfaces for advanced technological applications.

Research on Character of Physical Field Distribution in High Speed Ball-End Milling Hardened Steel

In order to mend cutting instability of ball-end milling cutter caused by the changes of cutting loads in high speed milling hardened steel, we perform the modal analysis and heat-force coupling field analysis of cutter, carry out the experiment of high speed milling hardened steel, investigate the character and effect factor of physical field distribution in high speed ball-end milling hardened steel, and propose the method about the match of diameter and overhang for depressing cutter vibration. Results indicate that the decrease in the ratio of overhang to diameter can transform the first modal shape of cutter from bending modal shape into torsion modal shape. The diameter of cutter is from 30mm to 20mm, the overhang of cutter is from 125mm to 90mm, heat-force coupling field distribution changes slightly, resonance of cutter does not occur, and efficiency in machining hardened steel can be improved effectively by higher cutting speed.

Computer Aided Design and New Manufacturing Process of Spherical Hob

According to the working principle of spherical hob, computing formulae of normal and axial profile of the spherical hob are deduced, and calculation methods of other main parameters are introduced in the paper. Then the computer aided design and calculation of spherical hob is realized by Visual Basic programming language, which increases the calculation speed and accuracy. And the new manufacturing process of making spherical hob blade by using gear shaper cutter is put forward which can be finished on universal machine tool, so the application and popularization of spherical of hob can be promoted. At last the experiment proves that the internal gear machined by spherical hob meets the demand of precision.

A Study of Reduced Beam Section Profiles using Finite Element Analysis

Reduced beam section (RBS) is one of the several connection types, which is economical and popular for use in new steel moment frame structures in seismic zone. To form RBS connection, some portion of the beam flanges at a short distance from column face is purposefully trimmed so that the yielding and plastic hinge occurs within this area of flanges. Use of RBS connection is found advantageous due to: a) the shear force in the panel zone is reduced; b) the force demand in column continuity plates i.e. stiffeners are reduced; and c) strong-column - weak-beam requirement is satisfied. Although, radius cut RBS is qualified by ANSI/AISC, FEMA codes, various flange cut shapes like constant, tapered, radius cut, drilled holes are possible to reduce the cross sectional area of beam flanges. The purpose of this study is to understand behavior of RBS beam-to-column moment connections for various flange cut geometries. This document represents nonlinear finite element analysis of the connection models performed using the computer program, ANSYS/Multiphysics Keywords - Steel structures, steel connections, reduced beam section, RBS profiles

Corner cuts are close to optimal: From solid grids to polygons and back

We study the solution quality for min-cut problems on graphs when restricting the shapes of the allowed cuts. In particular we are interested in min-cut problems with additional size constraints on the parts being cut out from the graph. Such problems include the bisection problem, the separator problem, or the sparsest cut problem. We therefore aim at cutting out a given number m of vertices from a graph using as few edges as possible. We consider this problem on solid grid graphs, which are finite, connected subgraphs of the infinite two-dimensional grid that do not have holes. Our interest is in the tradeoff between the simplicity of the cut shapes and their solution quality: we study corner cuts in which each cut has at most one right-angled bend. We prove that optimum corner cuts get us arbitrarily close to a cut-out part of size m, and that this limitation makes us lose only a constant factor in the quality of the solution. We obtain our result by a thorough study of cuts in polygons and the effect of limiting these to corner cuts.

Tooth-Leap Shaping Method for Helical Gears

In order to reduce cyclic variation in rotational speed of generated gears or shaper cutter induced by additional rotation during shaping, tooth-leap shaping method for helical gears was proposed. Based on fundamentals of helical gears shaping kinematics, principle of tooth-leap shaping for helical gears was introduced. Furthermore, mathematic models of tooth-leap shaping motions for helical gears are established. Finally, several examples are calculated, results show that cyclic variation in rotational speed of generated helical gear can be reduced largely by tooth-leap shaping method comparing with conventional shaping method. Consequently this method will make shaping motions of helical gears more smooth and improve the machining accuracy of helical gears.

Blasting Demolition Technology and Vibration Testing of 210m Reinforced Concrete Chimney

This paper describes the successful experience of the directional control blasting of 210m-high reinforced concrete chimney of Nanchang Power Plant in Jiangxi Province called as “First height in Asia”. It emphatically describes the pretreatment measures, blasting cut shape and size, blasting parameters, electronic digital detonator detonating network and blasting safety technology. And the blasting vibration was tested and analyzed, and this paper presents the method for opening the arch overlarge oriented window and comprehensive protection method for anti-flyrock splash, vibration reduction and dustfall. Especially, the electronic digital detonator was first applied in the blasting demolition of 210m-high structures, it improves the delay precision and also has a good anti-stray current effect to ensure that the blasting can be safely implemented in the power plant, and it has a good application prospect in the future large-scale and high level complex engineering blasting.