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Yusuf Altintas - One of the best experts on this subject based on the ideXlab platform.

  • the effect of serration on mechanics and stability of Milling Cutters
    International Journal of Machine Tools & Manufacture, 2010
    Co-Authors: Zoltan Dombovari, Yusuf Altintas, Gabor Stepan
    Abstract:

    The machining behaviour of special serrated Milling tools are investigated. These Cutters are most commonly used for roughing operations of superalloys such as titanium and nickel based alloys which prevent high cutting speeds due to their high cutting forces and low thermal conductivity. During the experimental study, these drawbacks were avoided with the usage of aluminium alloy that allows more convenient machining circumstances and high tooth passing frequencies compared to the frequencies of the essential vibration modes. By means of a general cutting force model, simulations point out the fact that the serrated Cutters require lower drive torque than their non-serrated counterparts, while our corresponding measurements validate our model. A regenerative dynamic model is constructed up directly in the modal space using the modal representation of the tool/toolholder/spindle structure and linear stability analyses are performed by the so-called semi-discretization method. The significantly larger parameter domains of stable cutting and their predicted feed dependency for these serrated mills are confirmed by chatter tests. As a result of these investigations, the practical advantages of the serrated Cutters are confirmed: while they remove the same specific amount of materials using lower drive torque, their productivity can also be increased using higher stable depth of cuts compared to their non-serrated counterparts even in case of difficult-to-cut materials like titanium. The constructed mechanical model also provides an adequate tuning of the cutting parameters and the serration waves in order to optimize the process for easy-to-cut materials like aluminium.

  • mechanics and dynamics of general Milling Cutters part i helical end mills
    International Journal of Machine Tools & Manufacture, 2001
    Co-Authors: Serafettin Engin, Yusuf Altintas
    Abstract:

    A variety of helical end mill geometry is used in the industry. Helical cylindrical, helical ball, taper helical ball, bull nosed and special purpose end mills are widely used in aerospace, automotive and die machining industry. While the geometry of each cutter may be different, the mechanics and dynamics of the Milling process at each cutting edge point are common. This paper presents a generalized mathematical model of most helical end mills used in the industry. The end mill geometry is modeled by helical flutes wrapped around a parametric envelope. The coordinates of a cutting edge point along the parametric helical flute are mathematically expressed. The chip thickness at each cutting point is evaluated by using the true kinematics of Milling including the structural vibrations of both cutter and workpiece. By integrating the process along each cutting edge, which is in contact with the workpiece, the cutting forces, vibrations, dimensional surface finish and chatter stability lobes for an arbitrary end mill can be predicted. The predicted and measured cutting forces, surface roughness and stability lobes for ball, helical tapered ball, and bull nosed end mills are provided to illustrate the viability of the proposed generalized end mill analysis.

  • analytical prediction of three dimensional chatter stability in Milling
    Jsme International Journal Series C-mechanical Systems Machine Elements and Manufacturing, 2001
    Co-Authors: Yusuf Altintas
    Abstract:

    The chip regeneration mechanism during chatter is influenced by vibrations in three directions when Milling Cutters with ball end, bull nose, or inclined cutting edges are used. A three dimensional chatter stability is modeled analytically in this article. The dynamic Milling system is formulated as a function of cutter geometry, the frequency response of the machine tool structure at the cutting zone in three Cartesian directions, cutter engagement conditions and material property. The dynamic Milling system with nonlinearities and periodic delayed differential equations is reduced to a three dimensional linear stability problem by approximations based on the physics of Milling. The chatter stability lobes are predicted in the frequency domain using the proposed analytical solution, and verified experimentally in Milling a Titanium alloy with a face Milling cutter having circular inserts.

  • generalized modeling of mechanics and dynamics of Milling Cutters
    CIRP Annals, 2001
    Co-Authors: Yusuf Altintas, Serafettin Engin
    Abstract:

    Abstract This paper presents a generalized mathematical model of most helical end mills and inserted Cutters used in industry. The end mill geometry is modeled by wrapping the helical flutes around a parametric envelope of a cutter body. The edge geometry for inserted cutter is defined in the local coordinate system of each insert, and placed and oriented on the cutter body using cutter's global coordinate system. The coordinates of a cutting edge are mathematically expressed for both cases. The chip thickness at each cutting point is evaluated by using the true kinematics of Milling including the structural vibrations of both cutter and workpiece. By integrating the process along each cutting edge or tooth, which are in contact with the workpiece, the cutting forces, vibrations, dimensional surface finish, and chatter stability lobes for arbitrary end mills and inserted Cutters are predicted. The predicted and measured cutting forces, surface roughness and stability lobes for helical tapered ball, bull nosed end mills and inserted Cutters are provided to illustrate the viability of the proposed generalized end mill analysis. The algorithms are integrated to an advanced cutting process simulation program which is used for process planning of Milling operations to avoid chatter vibrations, torque and power limit constraints, and dimensional form errors.

  • Mechanics and dynamics of general Milling Cutters.: Part II: inserted Cutters
    International Journal of Machine Tools and Manufacture, 2001
    Co-Authors: Serafettin Engin, Yusuf Altintas
    Abstract:

    Inserted Cutters are widely used in roughing and finishing of parts. The insert geometry and distribution of inserts on the cutter body vary significantly in industry depending on the application. This paper presents a generalized mathematical model of inserted Cutters for the purpose of predicting cutting forces, vibrations, dimensional surface finish and stability lobes in Milling. In this paper, the edge geometry is defined in the local coordinate system of each insert, and placed and oriented on the cutter body using the cutter's global coordinate system. The cutting edge locations are defined mathematically, and used in predicting the chip thickness distribution along the cutting zone. Each insert may have a different geometry, such as rectangular, convex triangular or a mathematically definable edge. Each insert can be placed on the cutter body mathematically by providing the coordinates of the insert center with respect to the cutter body center. The inserts can be oriented by rotating them around the cutter body, thus each insert may be assigned to have different lead and axial rake angles. By solving the mechanics and dynamics of cutting at each edge point, and integrating them over the contact zone, it is shown that the Milling process can be predicted for any inserted cutter. A sample of inserted cutter modeling and analysis examples are provided with experimental verifications.

Zhanqiang Liu - One of the best experts on this subject based on the ideXlab platform.

  • cutting performance of solid ceramic end Milling tools in machining hardened aisi h13 steel
    International Journal of Refractory Metals & Hard Materials, 2016
    Co-Authors: Zhanqiang Liu, Ing Wang
    Abstract:

    Abstract Ceramic tools have been widely used in the cutting of hard-to-machine materials, but the applications of solid ceramic Milling Cutters are limited due to their design and manufacturing restrictions. This research investigates the cutting performances of four solid ceramic end Milling tools including Si3N4, Ti(C,N), SG4 and LT55 in machining hardened AISI H13 steel (HRC 60-62). The results show that the cutting forces of ceramic end Milling tools are less than that of the referenced cemented carbide tool, and such ceramic tools of Si3N4, Ti(C,N) and LT55 produce better surface qualities and have longer tool lives. With excellent mechanical peoperties including hardness, bending srength and fracture toughness, the ceramic tool of Ti(C,N) presents the best cutting performance taking the cutting force, machined surface quality and tool life in consideration simultaneously. The research has proven the application feasibility of ceramic materials in the manufacture of solid tools. The solid ceramic end Milling tools are geometric extensions for traditional ceramic tools and they can be used in machining hardened steels.

  • Effect of cutter geometric configuration on aerodynamic noise generation in face Milling Cutters
    Applied Acoustics, 2014
    Co-Authors: Zhanqiang Liu
    Abstract:

    Abstract Aerodynamic noise spectrum of rotary face Milling Cutters consists of a broad range of high frequencies and discrete tones. This paper aims to develop a method to calculate the aerodynamic noise generation and propagation by rotary face Milling Cutters. The effects of Milling cutter geometry on the generation of aerodynamic noise are analyzed. Based on the computational fluid dynamics (CFD) method, the Ffowcs Williams–Hawkings (FW–H) equation is used to predict the sound pressure level (SPL) of aerodynamic noise in face Milling Cutters. The accurate calculation of time-varying flow variables along with the rotation of cutter is very important for the prediction of aerodynamic noise. In this case, the Navier–Stokes (N–S) equation is employed to evaluate the pressure and velocity fields around the Milling Cutters, first in a steady mode with the Multiple Reference Frames (MRF) model, and then in an unsteady mode with sliding mesh technique (SMT) by introducing the steady flow variables as its initial fields. It is found that both the overall aerodynamic noise due to the entire cutter and the aerodynamic noise only due to the cutter gullet regions are significantly affected by the number of cutter teeth/gullet regions. Moreover, six representative Milling Cutters with different tooth numbers and geometries of gullet regions are chosen to study the effects of gullet configuration on aerodynamic noise generation, and the characteristics of noise spectra generated by the Cutters are analyzed. The aerodynamic noise generated only by the cutter gullet regions is found to be strongly dependent on the gullet design-volume and shape. The results also reveal that the gullet design advantage of Cutter C in reducing noise generation among the eight-tooth designs, and the gullet design advantage of Cutter A in reducing noise generation among the five and seven-tooth designs in this investigation.

  • Numerical Analysis of Aeroacoustic Noise for High-Speed Face Milling Cutters in Three Dimensional Unsteady Flow Fields
    Journal of Manufacturing Science and Engineering-transactions of The Asme, 2012
    Co-Authors: Zhanqiang Liu
    Abstract:

    Aeroacoustic noise produced by high speed face Milling Cutters is a serious environmental concern. This paper develops a modeling approach to investigate the aeroacoustic noise generation and propagation by the idling face Milling Cutters. The approach consists of two parts: (1) an aerodynamic model for evaluating the flow fields based on the Navier–Stokes (N–S) equation and (2) an aeroacoustic model for predicting the acoustic noise by using the Ffowcs Williams and Hawkings (FW–H) equation. Both the steady mode with the multiple reference frames (MRF) model and the unsteady mode with the sliding mesh technique by introducing steady flow variables as its initial fields are simulated. The cutter gullet regions and the insert rake face regions are found to be the primary contributors in noise generation through spectral analysis of noise sources. The acoustic noise in face Milling is significantly affected by the cutter diameter and the number of cutter teeth. The noise directivity is found in vertical plane, and the irregular tooth spacing can spread the maximum sound power at the rotating frequency to higher frequencies. In addition, experiments are conducted to measure the acoustic noise from two high speed Milling Cutters. It is found that the experimental results are generally in good agreement with the simulations.

W H Kao - One of the best experts on this subject based on the ideXlab platform.

  • design and performance analysis of ticn coated cemented carbide Milling Cutters
    Journal of Materials Processing Technology, 1999
    Co-Authors: S H Yao, C S Wei, W H Kao
    Abstract:

    Abstract The Taguchi method was employed to analyze and optimize titanium carbonitride films of cemented carbide (WC–6%Co–10%TiC–8%TaC) indexable Milling Cutters regarding machining conditions. Six variables, i.e. film construction, cutting speed, feed rate, depth of cut, workpiece hardness and Milling type, were considered. The results showed that the film construction was the most dominant variable, with a percentage contribution to the overall performance of the Milling system as high as 46.10%. Through statistical calculation, an optimum variable combination was obtained, the optimal film construction being 3 μm TiCN+2 μm TiCN (from the substrate to the top) rather than 5 μm TiCN alone. The resultant flank wear achieved 380 and 280% improvement compared with the uncoated and 5 μm TiCN-coated Cutters.

  • design and performance analysis of ticn coated cemented carbide Milling Cutters
    Surface Engineering, 1999
    Co-Authors: S H Yao, C S Wei, W H Kao
    Abstract:

    AbstractThe Taguchi method was employed to analyse and optimise the use of TiCN films on cemented carbide (WC–6Co–10TiC–8TaC) indexable Milling Cutters with respect to machining conditions. Six variables, i.e. film construction, cutting speed, feedrate, depth of cut, workpiece hardness, and Milling type, were considered. The results showed that the film construction was the most dominant variable, with a percentage contribution as high as 46·10% to the overall performance of the Milling system. Through statistical calculation an optimal variable combination was obtained, and the optimal film construction was found to be 3 μm TiN + 2 μm TiCN (from the substrate to the surface) rather than 5 μm TiCN alone. The resultant flank wear showed 380 and 280% improvement over the uncoated and 5 μm TiN coated Cutters respectively.

Shucai Yang - One of the best experts on this subject based on the ideXlab platform.

  • optimising milled titanium alloy concave surface quality with micro textured ball end Milling Cutters
    International Journal of Manufacturing Research, 2021
    Co-Authors: Xin Tong, Shucai Yang, Xianli Liu, Lihui Wang
    Abstract:

    The cutting speed at the lowest point of a ball-end Milling cutter is zero, which results in poor workpiece surface quality and serious cutter wear. To alleviate this problem, a micro-texture can be processed on the rake face of a ball-end Milling cutter to provide an anti-friction and anti-wear mechanism. The objective of the work reported here is to reduce cutter wear and optimise workpiece surface quality. By using a mathematical model of row spacing to analyse the differential geometric relationship between Cutters and surfaces at their contact point, we have been able to obtain optimal cutter orientation. This was verified by simulating concave surface machining. Experiments were then conducted to verify the approach and the results showed that when the cutter orientation is adjusted to its optimum, the surface quality of the workpiece processed by a micro-textured ball-end Milling cutter is at its best. [Submitted 10 May 2018; Accepted 28 July 2019]

  • micro texture design criteria for cemented carbide ball end Milling Cutters
    Journal of Mechanical Science and Technology, 2020
    Co-Authors: Shucai Yang, Tianjiao Wang, Wei Ren
    Abstract:

    Given the serious work hardening phenomenon, high chemical activity, severe tool wear, and poor workpiece surface quality during the cutting of titanium alloys, placing micro-texture on the tool surface decreases the tool-chip contact area and friction and plays the role of wear resistance and friction reduction. In order to improve the cutting performance of cutting tools, the present study examins the effect of micro-texture parameters of a cemented carbide ball-end Milling cutter on cutting force, tool wear, and workpiece surface roughness and establishes a regression analysis model via regression analysis. We consider the cutting performance of a cemented carbide micro-texture ball-end Milling cutter as an evaluation standard. A genetic algorithm is applied to the multi-objective optimization of micro-texture parameters, and a regression analysis model of micro-texture design criteria is established. This provides a standardised reference to select standard micro-texture parameters in the design and preparation of a cemented carbide micro-texture ball-end Milling cutter.

  • The Surface Integrity of Titanium Alloy When Using Micro-Textured Ball-End Milling Cutters
    MDPI AG, 2018
    Co-Authors: Shucai Yang
    Abstract:

    Processing certain kinds of micro-textures onto the surface of tools can improve their wear resistance, reduce the friction between them and machined surfaces, prolong their service life and improve their processing efficiency. When Milling titanium alloy with ball-end Milling Cutters, the cutting force and the cutting heat causes plastic deformation and a concentration of stress on workpiece surfaces, damaging their surface integrity. In this paper, we report on a test involving the Milling of titanium alloy, where a micro-texture was placed onto the front of a ball-end cutter and the surface roughness and work hardening of the machined surface were studied. The orthogonal experiment was designed around changes in the diameter of the micro-texture, its depth, the spacing between individual micro-pits, and its distance from the cutting edge. Data from the experiment was then used to assess the influence changes in the micro-texture parameters had upon the roughness and hardening of the surface. The data was processed and analyzed by using regression analysis and a prediction model for surface roughness and work hardening was established. The reliability of the model was then verified. The contents of this paper provide a theoretical basis for improving the cutting performance and the surface machining quality of cemented carbide tools

  • Temperature Field of Tool Engaged Cutting Zone for Milling of Titanium Alloy with Ball-End Milling
    MDPI AG, 2018
    Co-Authors: Shucai Yang, Minli Zheng, Quan Wan, Yuhua Zhang
    Abstract:

    When Milling titanium alloy, the cutting temperature has a strong impact on the degree of tool wear and, in turn, tool life and the surface quality of the workpiece. The distribution of the temperature field on a tool’s rake face can be improved through the use of micro-textures, which help to reduce friction and, ultimately, wear on the tool. In this paper we present a new way to measure cutting temperature and examine heat distribution when Milling titanium alloy with micro-textured ball-end Milling tools. We first establish the heat flux density function for the contact area between the workpiece and the tool and then for the rest of the tool. Thermal stress simulation shows that adhesive wear tends to happen in the contact area and on the flank face, rather than at the tip of the tool, with the temperature distribution gradient for the rest of the tool being more uniform. The maximum value for thermal stress on the cutting edge was 2.0782 × 106 Pa. This decrease as you move away from the cutting edge along the contact area between the tool and the workpiece. Maximum deformation of the tool is also mainly concentrated at the principal contact point, with a value of 1.9445 × 10−9 m. This, too, decreases as you move away from the cutting edge and into the rest of the contact area. This research provides the basis for the optimization of tool structure and further investigation of the thermo-mechanical coupling behavior of micro-textured ball-end Milling Cutters when Milling titanium alloy

Wei-fang Chen - One of the best experts on this subject based on the ideXlab platform.

  • Quality assurance for concave-arc ball-end Milling
    2016
    Co-Authors: Wei-fang Chen, Hsin Yi Lai, C-k Chen
    Abstract:

    Abstract: This paper presents a systematic modelling procedure for assessing the pro®le quality of concave-arc ball-end (CABE) Milling Cutters with a cylindrical shank. CABE Milling Cutters are widely used in three-axis numerical control (NC) machines for producing dies and moulds of complicated surface features. Evaluation of the contour quality of the CABE Milling cutter is crucial in enhancing machining accuracy and eciency. In order adequately to describe the shape of the clamped cutter, the centre-line axis of the minimum circumscribed cylinder of the cylinder shank is taken as the referenced datum axis. The minimum circumscribed concave-arc revolving surface and the minimum circumscribed spherical surface are carefully derived in sequence. The pro®le errors and tolerances are estimated. The quality of the CABE Milling cutter is assured by using the proposed modelling procedure, and several numerical examples are presented to illustrate its eVectiveness. The results indicate that the present method is feasible and can be extended to enhance the quality of various revolving Cutters

  • a systematic mathematical modeling approach for the design and machining of concave arc ball end Milling Cutters with constant helical pitch
    Journal of Applied Science and Engineering, 2007
    Co-Authors: Shanddad Liaw, Wei-fang Chen
    Abstract:

    As the use of NC techniques to machine the freeform and complex surfaces of dies and molds has increased, the demand for revolving helical Cutters with specialized geometries has risen. This paper develops a systematic modeling approach for the design and NC machining of concave-arc ball-end Milling Cutters with a constant helical pitch. The section profile of groove and grinding wheel in the NC machining of the concave-arc ball-end Milling Cutters with constant pitch are concluded. The cutting edge is defined with a constant pitch and the grinding wheel is specified in terms of the maximum radius of the cutter. By employing the envelope and inverse envelope theories, the sections of grinding wheel and the radial feed, axis feed, and relative displacement of the grinding wheel during NC machining of the cutter are systematically designed. Based on the maximum sectional radius of the cutter, the principles of inverse envelope theory are then employed to establish the sectional profile of the grinding wheel required to produce the designed cutter using a two-axes NC machine. Models are then presented to continue the radial and axial feeding velocities of the grinding wheel during machining, together with its relative displacement. The proposed models are verified via computer simulation and are found to yield satisfactory results. The models presented in this study are intended to supply a general reference for the automatic design and manufacture of helical Cutters with a constant pitch.

  • a study of design and manufacturing models for circular arc ball end Milling Cutters
    Journal of Materials Processing Technology, 2005
    Co-Authors: Weiya Chen, Shanddad Liaw, Paichi Chang, Wei-fang Chen
    Abstract:

    Abstract The paper presents a systematic manufacturing model for producing the circular-arc ball-end Milling (CABEM) cutter. Having first defined the helical angle as the angle between the cutting edge and the axis of rotation of the cutter, the geometric shapes of helical grooves and cutting edge profiles are analytically derived. The feed speed of the grinding wheel in the radial direction is modified according to the cross-section of the groove that passes through the centre of the cutter sphere. The models that are used to calculate the actually obtained groove, and the method of computer simulation are also included. To further enhance the accuracy of the mathematical models, a compensatory machining process, which eliminates residual profile on the revolving surface, is also presented.

  • Quality assurance for concave-arc ball-end Milling Cutters
    Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture, 2003
    Co-Authors: Wei-fang Chen, Cha'o-kuang Chen
    Abstract:

    AbstractThis paper presents a systematic modelling procedure for assessing the profile quality of concave-arc ball-end (CABE) Milling Cutters with a cylindrical shank. CABE Milling Cutters are widely used in three-axis numerical control (NC) machines for producing dies and moulds of complicated surface features. Evaluation of the contour quality of the CABE Milling cutter is crucial in enhancing machining accuracy and efficiency. In order adequately to describe the shape of the clamped cutter, the centre-line axis of the minimum circumscribed cylinder of the cylinder shank is taken as the referenced datum axis. The minimum circumscribed concave-arc revolving surface and the minimum circumscribed spherical surface are carefully derived in sequence. The profile errors and tolerances are estimated. The quality of the CABE Milling cutter is assured by using the proposed modelling procedure, and several numerical examples are presented to illustrate its effectiveness. The results indicate that the present meth...

  • design and nc machining of concave arc ball end Milling Cutters
    The International Journal of Advanced Manufacturing Technology, 2002
    Co-Authors: Wei-fang Chen, Cha'o-kuang Chen, Hsin Yi Lai
    Abstract:

    The paper presents a geometric modelling approach for the precision design and NC machining of a concave-arc ball-end Milling (CABEM) cutter which is an important tool for mould-making industries. This paper presents systematic models of the cutting edge, helical groove, and grinding wheel design for the NC machining of a CABEM cutter. Both the normal to the revolving axis and the tangent to the groove, are used to derive the required precision sectional profiles of the grinding wheel. In compliance with the maximal sectional radius of the cutter, the profile of the groove section and both the radial and axial cutting speeds of the grinding wheel are computed in sequence. Using the computer simulation results of the groove actually obtained, this paper proposes a method to resolve the problems of the residual revolving surface and the narrow cutting edge strip. This paper is intended to serve as a reference for the design and NC machining of Cutters of this type.