The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform

Mingzhe Li - One of the best experts on this subject based on the ideXlab platform.

  • an investigation on roll adjusting radius in three dimensional rolling process for three dimensional surface parts
    Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture, 2015
    Co-Authors: Daming Wang, Mingzhe Li
    Abstract:

    Three-dimensional rolling is a novel Forming process for three-dimensional surface parts, which combines the rolling process with multi-point Forming Technology. This process employs a pair of Forming rolls as a Forming tool; the residual stress of sheet metal makes the sheet metal generate three-dimensional deformation by controlling the nonuniform distribution of roll gap of the Forming rolls. In this article, two types of Forming processes are investigated for three-dimensional surface parts with the same target shape in different roll adjusting radius. The roll adjusting radius of a Forming process is much larger than the target transverse curvature radius of the Forming part, and the roll adjusting radius of another Forming process is equal to the target transverse curvature radius of the Forming part. Finite element analysis models are established; spherical and saddle surfaces are simulated. The corresponding experimental results are obtained. The dimensional accuracy of the Forming parts using the...

  • three dimensional sheet metal continuous Forming process based on flexible roll bending principle and experiments
    Journal of Materials Processing Technology, 2012
    Co-Authors: Zhongyi Cai, Mingzhe Li, Yingwu Lan
    Abstract:

    Abstract To effectively manufacture three-dimensional sheet metal parts with various curvatures produced in small batch quantities, continuous sheet metal Forming, a new flexible Forming Technology is being developed. This process employs an upper flexible roll and two lower flexible rolls as a Forming tool, and the shape of a flexible roll can be changed in vertical direction. With the rotation of flexible rolls, the sheet metal is bent in longitudinal and transverse directions simultaneously and is formed continuously. In the present study, the three-dimensional surface of formed part is described by sweep surface based on the characteristic of the Forming process and the arc-length parametric equation for describing continuous Forming part is developed. The three-roll bending deformation of sheet metal in longitudinal direction is analyzed and the longitudinal curvature equation of the formed part is derived. The shape of flexible roll axis controlled at a number of points is represented by the cubic spline curve and the transverse curvature of the formed part after springback is then calculated piecewise. Typically experiments for Forming concave shape surface and saddle-type surface have been performed, the experiment results are measured and analyzed by a binocular stereo vision measurement system, it is demonstrated that the formed surfaces are in good agreement with the desired shapes and the presented equations are useful for the continuous Forming process design.

  • multi point Forming Technology for sheet metal
    Journal of Materials Processing Technology, 2002
    Co-Authors: Mingzhe Li, Zhongyi Cai, Zhou Sui, Q G Yan
    Abstract:

    Abstract Multi-point Forming (MPF) is an advanced manufacturing Technology for three-dimensional sheet metal parts. In this paper, an MPF integrated system is described that can form a variety of part shapes without the need for solid dies, and given only geometry and material information about the desired part. The central component of this system is a pair of matrices of punches, and the desired discrete die surface is constructed by changing the positions of the punches though CAD and a control system. Typical examples show the applicability of the MPF Technology. Wrinkles and dimples are the major Forming defects in the MPF process, but numerical simulation is a feasible way to predict Forming defects in MPF. In conventional stamping, the method to form sheet metal with a blankholder is an effective way to suppress wrinkling; and the same is true in MPF. An MPF press with a flexible blankholder was developed, and the Forming results indicated the Forming stability of this technique. Based on the flexibility of MPF, varying deformation path MPF and sectional MPF were explored that cannot be realized in conventional stamping. By controlling each punch in real-time, a sheet part can be manufactured along a specific Forming path. When the path of deformation in MPF is designed properly, Forming defects will be avoided completely and large deformation achieved. A workpiece can be formed section by section though the sectional MPF, and this technique makes it possible to manufacture large size parts in a small MPF press. Some critical experiments were performed that confirmed the validity of the two special MPF techniques.

Reine Kopp - One of the best experts on this subject based on the ideXlab platform.

  • flexible sheet Forming Technology by double sided simultaneous shot peen Forming
    CIRP Annals, 2002
    Co-Authors: Reine Kopp, J Schulz
    Abstract:

    Abstract The exceptionally flexible Forming Technology shot peen Forming is used primarily on large, three-dimensionally curved sheet metal in the aircraft and aerospace industries. Depending on the kinetic shot energy, both convex and concave curvatures will be generated. The most recent development, double-sided simultaneous shot peen Forming, brings about a higher productivity of the entire process. FEM simulations of single and multiple impacts are presented in order to evaluate the characteristics of concave curvatures generated by both single and double-sided peen Forming.

  • mushy semi solid metal Forming Technology present and future
    CIRP Annals, 2002
    Co-Authors: M Kiuchi, Reine Kopp
    Abstract:

    Mushy, semi-solid and/or thixo processing of metals (alloys) is becoming popular as a new potential manufacturing Technology for parts and components in automobile, electronic and machine industries. Internal structures and mechanical properties of those metals that include solid and liquid fractions are quite different from those of hot or molten metals. Diversified possibilities are known today to process those metals based on die casting, hot metal Forming or polymer injection technologies, each of which has its own specific advantages and disadvantages. Up to now thixocasting and thixomolding have been used in industrial applications for light metal alloys. The potentials of those processes are wider by far however. They include the processing of specially designed alloys and composites, the combination of Forming and joining processes as well as reduction of production costs and energy consumption.

  • incremental formulation for the prediction of flow stress and microstructural change in hot Forming
    Journal of Manufacturing Science and Engineering-transactions of The Asme, 1998
    Co-Authors: Ju Yanagimoto, Kai F Karhause, A J And, Reine Kopp
    Abstract:

    In metal Forming, the workpieces are formed to the desired shapes or profiles. Especially in in hot Forming, the microstructure of workpiece changes during plastic deformation. Modern Forming technologies allow to control the shape and the microstructure of formed product in a wide range and will gain increasing importance in future in the field of metal Forming. In order to develop this Forming Technology which may be called macroscopic microscopic materials processing. theoretical predictions of plastic deformation as well as microstructural changes are indispensable. A new mathematical formulation to predict flow stress and microstructural change in hot Forming will be presented in this paper. This model is based on an incremental formulation taking the dislocation density as a representative variable.

  • some current development trends in metal Forming Technology
    Journal of Materials Processing Technology, 1996
    Co-Authors: Reine Kopp
    Abstract:

    Abstract Various trends in metal-Forming Technology which will change future plant construction and production Technology are already becoming apparent. The report describes the shortening, flexibilization and integration of a number of processes. Moreover hollow structure technologies become more and more interesting for innovative production. Furthermore FEM-simulation and optimization, also reported on in the paper, are increasingly important tools for the development of new or improved processes and plants. In view of the need to minimize production costs, to increase environmental compatibility and to manufacture products to a defined quality standard, long, complex processes should be shortened as far as is possible or necessary. In the field of strip production, mention should be made of the development of thin slab Technology and thin strip casting, in which certain manufacturing steps are eliminated completely. For formed parts, possible methods for shortening the process include Forming in the solidus-liquidus range (thixoForming). Another possibility is a combination of Forming with heat treatment. Shorter process chains often mean more favourable mechanical properties for the products and hence new applications. Against a background in which Forming processes are becoming more flexible in order to enlarge the spectrum of products, it is necessary to use flexible Forming units with adaptable links to preceding and succeeding steps as well as universal dies and intelligent controls. For example, robot-manipulated open die forging allows reproducible manufacture of complex forgings with relatively small allowances. A variable rolling gap in the rolling process means that sheet metals can be produced with a defined longitudinal thickness profile matching the load case for the subsequent component. The integration of different production processes also paves the way for new approaches. Existing process limits can be extended and the final properties of components optimized by using partial heating methods during or directly after Forming and by coupling Forming processes with parting or joining techniques. A promising approach in the field of innovative lightweight construction is the systematic use of hollow structures; new processes for generating cavities and production techniques for processing the new hollow structures are being developed. Apart from suitable tests, physical and numerical simulation can be used to optimize existing or develop new methods of manufacture. Physical simulation may be especially successful in solving questions of material flow. A new material flow simulator is presented. Numerical simulation is used especially for quantitative analysis of local process variables; methods have recently been developed for taking the modification of structure during the Forming process into account.

Andrzej Kocanda - One of the best experts on this subject based on the ideXlab platform.

  • experimental investigations on average surface roughness in negative incremental sheet metal Forming process
    Journal of Manufacturing Technologies, 2017
    Co-Authors: Amrut Mulay, Syed Ismail, Andrzej Kocanda
    Abstract:

    Single point incremental Forming (SPIF) is an innovative, flexible and cost efficient process to manufacture a small batch of complex sheet metal parts. The punch produces permanent local plastic deformation imposed by CNC machine. However, this Forming Technology still carries few limitations. The effective study of SPIF in terms of quality production and process optimization has always been a challenge for the researchers. The surface roughness of formed product is one of the key challenges for this technique. An attempt has been made to investigate the effect of SPIF process parameters such as feed rate, step depth, tool diameter, and sheet thickness on surface roughness while Forming of AA5052 H32 alloy sheet. Response surface methodology (RSM) with the Box-Behnken design is used to develop a mathematical model in terms of the above parameters. An analysis of variance (ANOVA) test shows that step depth, tool diameter and their mutual interaction has a significant effect on the surface roughness (Pl 0.0001). The confirmation experiments were performed to check the validity of prediction model. The fractography analysis has performed at the optimum condition to understand the nature of fractured surfaces.

Zhongyi Cai - One of the best experts on this subject based on the ideXlab platform.

  • three dimensional sheet metal continuous Forming process based on flexible roll bending principle and experiments
    Journal of Materials Processing Technology, 2012
    Co-Authors: Zhongyi Cai, Mingzhe Li, Yingwu Lan
    Abstract:

    Abstract To effectively manufacture three-dimensional sheet metal parts with various curvatures produced in small batch quantities, continuous sheet metal Forming, a new flexible Forming Technology is being developed. This process employs an upper flexible roll and two lower flexible rolls as a Forming tool, and the shape of a flexible roll can be changed in vertical direction. With the rotation of flexible rolls, the sheet metal is bent in longitudinal and transverse directions simultaneously and is formed continuously. In the present study, the three-dimensional surface of formed part is described by sweep surface based on the characteristic of the Forming process and the arc-length parametric equation for describing continuous Forming part is developed. The three-roll bending deformation of sheet metal in longitudinal direction is analyzed and the longitudinal curvature equation of the formed part is derived. The shape of flexible roll axis controlled at a number of points is represented by the cubic spline curve and the transverse curvature of the formed part after springback is then calculated piecewise. Typically experiments for Forming concave shape surface and saddle-type surface have been performed, the experiment results are measured and analyzed by a binocular stereo vision measurement system, it is demonstrated that the formed surfaces are in good agreement with the desired shapes and the presented equations are useful for the continuous Forming process design.

  • multi point Forming Technology for sheet metal
    Journal of Materials Processing Technology, 2002
    Co-Authors: Mingzhe Li, Zhongyi Cai, Zhou Sui, Q G Yan
    Abstract:

    Abstract Multi-point Forming (MPF) is an advanced manufacturing Technology for three-dimensional sheet metal parts. In this paper, an MPF integrated system is described that can form a variety of part shapes without the need for solid dies, and given only geometry and material information about the desired part. The central component of this system is a pair of matrices of punches, and the desired discrete die surface is constructed by changing the positions of the punches though CAD and a control system. Typical examples show the applicability of the MPF Technology. Wrinkles and dimples are the major Forming defects in the MPF process, but numerical simulation is a feasible way to predict Forming defects in MPF. In conventional stamping, the method to form sheet metal with a blankholder is an effective way to suppress wrinkling; and the same is true in MPF. An MPF press with a flexible blankholder was developed, and the Forming results indicated the Forming stability of this technique. Based on the flexibility of MPF, varying deformation path MPF and sectional MPF were explored that cannot be realized in conventional stamping. By controlling each punch in real-time, a sheet part can be manufactured along a specific Forming path. When the path of deformation in MPF is designed properly, Forming defects will be avoided completely and large deformation achieved. A workpiece can be formed section by section though the sectional MPF, and this technique makes it possible to manufacture large size parts in a small MPF press. Some critical experiments were performed that confirmed the validity of the two special MPF techniques.

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

  • Forming mechanism and characteristics of a process for equal thickness in plane ring roll bending of a metal strip by twin conical rolls
    Journal of Materials Processing Technology, 2016
    Co-Authors: Lu Feng, He Yang
    Abstract:

    Abstract A flexible and precise Forming Technology for low-cost, high-efficient and high-quality manufacture of equal-thickness rings is urgently required. To this end, a novel technique for equal-thickness in-plane ring roll-bending of a metal strip (ET-IRS) by twin conical rolls is presented. In this process, the twin conical rolls are placed to form an equal-thickness roll gap. The rolls rotate in opposite directions with identical angular velocity. The strip is bitten into the roll gap by frictional force and compressed equally across its width. Under the varying boundary conditions supported by the varying tangential velocity (VTV) of the rolls and varying deformation zone (VDZ) across the strip width, monotonically varying elongation of the strip is obtained, the coordination of which creates an equal-thickness ring. The results show that the VTV of the rolls plays a major part in ring formation, whereas the VDZ has little influence. However, remarkable coupling effects of VDZ with VTV exist. In comparison with the tangential velocity of the roll, the outlet velocity at the inner half of the strip is larger, but the velocity at the outer half is smaller. As a result, the inner half and the outer half experience frictional drag and traction, respectively, which produces a bending moment acting on the strip. The deformation characteristics of ET-IRS studied by simulation and experiment demonstrate that gradients exist in the radial and hoop strain components and outlet velocity of the strip across its width. Positive radial strain at the inner rim of the strip and negative strain at the outer rim result in positive and negative spread, respectively, leading to minimal resultant spread of the formed ring. The independently adjustable parameters, such as initial position of the strip z0, the roll gap t, the friction coefficient μ, the strip width b0 and the cone-apex angle α, affect the deformation. The gradient of radial strain increases with decreasing z0 and t and increasing μ and α, and the spread increases with increasing z0 and α and decreasing t and b0. The results indicate the Forming mechanism and characteristics of ET-IRS are considerably different from existing processes.

  • bp artificial neural network modeling for accurate radius prediction and application in incremental in plane bending
    The International Journal of Advanced Manufacturing Technology, 2015
    Co-Authors: He Yang, Honglie Zhang, Heng Li, Wenting Tang
    Abstract:

    Incremental in-plane bending (IIB) is a new and advanced flexible manufacturing Technology for small-lot production of strip with various bending radii. The strip of sheet metal is bent incrementally by a beating inclined punch. The bending radius is strongly affected by mechanical properties of the material, geometry of the strip, and processing parameters. It is difficult to predict the bending radius due to the complex synergistic effects of the controlling parameters. How to predict the bending radius accurately has therefore become a key point to be urgently solved in the development of this advanced Forming Technology. In this paper, a model based on a back propagation neural network (BPNN) is introduced to reveal the relationship of bending radius with angle of die α, indentation s, pitch p, and width of strip w. Out of 14 different BPNN architectures trained, the 4-9-9-1 BPNN with two hidden layers having nine neurons trained with the Levenberg-Marquardt algorithm (trainlm) is found to be the optimum network model, and the prediction error is less than 2 % on average. Otherwise, a 1-9-9-4 reverse BPNN is developed to build the processing window for a given bending radius. Meanwhile, taking section moment of inertia I as a quantitative index of Forming stability, α, p, s, w0 are optimized as design variables in order to make objective functions of I maximized simultaneously. Finally, to verify its predictive capability, the present approach is applied to a case study, and the optimal combination of parameters for stable Forming during IIB is obtained.

  • research on the effects of coordinate deformation on radial axial ring rolling process by fe simulation based on in process control
    The International Journal of Advanced Manufacturing Technology, 2014
    Co-Authors: He Yang, Linlin Hu, Xiaoqing Chen
    Abstract:

    Radial-axial ring rolling process is an irreplaceable metal Forming Technology for manufacturing various seamless rings. However, during the process, there exists complex interaction of deformations in the radial and axial directions of the ring, so the coordinate deformation between radial and axial directions has crucial influences on the quality of the rolled ring. In this paper, a reliable FE model based on in-process control for the radial-axial ring rolling process has been established under the ABAQUS/Explicit platform. In this model, the motions of the rolls are real-time controlled based on in-process measurement. Then, taking the ratio of axial to radial feed amount as the key parameter, we explored the effects of the coordinate deformation between radial and axial directions on the radial-axial rolling of sleeve-type rings by FE simulations. It is found that the rational diameter growth rates become fewer for making the sleeve-type ring roundness stay well as the ratio of axial to radial feed amount decreases. The ratio of axial to radial feed amount has slight effects on the precision of the ring diameter when the diameter growth rate is large. With the ratio of axial to radial feed amount increasing, the deformation of the sleeve-type ring becomes more nonuniform, while the temperature distribution becomes more uniform.

  • recent developments in plastic Forming Technology of titanium alloys
    Science China-technological Sciences, 2011
    Co-Authors: He Yang, Mei Zhan
    Abstract:

    Titanium alloys have been used extensively in industry fields including aviation, aerospace and automobile due to their excellent comprehensive properties. Research and development of advanced plastic Forming Technology are of great importance to manufacturing titanium products of high performance and lightweight with low cost and short cycle. This paper analyzes the development tendencies of titanium alloy Forming Technology. Recent achievements in precision Forming, microstructure control and multi-scale simulation of titanium alloys are reviewed. The Forming techniques of large-sale integral complex components are presented.