Bending Machine Research Articles

Viscoplastic collapse of sharp-notched circular tubes under cyclic bending

This study discusses the experimental result of the viscoplastic response and collapse of sharp-notched 316L stainless steel tubes with different notched depths subjected to cyclic bending. The tube bending machine and curvature-ovalization measurement apparatus were used for conducting the symmetric curvature-controlled cyclic bending. To highlight the viscoplastic behavior, three different curvature-rates, 0.0035, 0.035 and 0.35 m−1s−1, were controlled. Observations of a certain curvature-rate reveal that five almost parallel lines corresponding to five different notch-depth (0.2, 0.4, 0.6, 0.8 and 1.0 mm) tubes were presented in the experimental relationship between the cyclic controlled curvature and the number of cycles needed to produce buckling on a log-log scale. However, the slopes for the three different curvature-rates are different. An empirical formulation was proposed to simulate the aforementioned relationship. When comparing with the experimental findings, the simulation was in good agreement with the experimental data.

Influence Parameters Analysis of Forming Quality and System Dynamics Simulation of Vertical Steel Bar Benting

The vertical steel bar bending forming is a kind of new process of bending method. The bending speed, bending radius and clamping length H which is the parameters of vertical steel bar bending machine , is directly affect the quality of bending forming parts. This paper calculated the length of reinforcement before being incised and the springback angle of bending steel bar which obtained the reasonable cutting length and bending Angle; Then based on rigid-flexible virtual prototype technology to build the dynamics model of vertical steel bar bending system. Through simulation analysis ,it obtained the relationship between bending speed, bending radius , clamping length H and forming quality of bending steel bar. In this paper, the analysis method have reference value to the design of similar steel bar bending machines.

The Effect of Nanocomposite Coating with Different Concentrations on Fatigue Life of Carbon Steel AISI 1045

Abstract Recently, nano-materials have received more attention due to their potential application as practical structural and functional materials. The unique mechanical properties of CNTs, especially their high strength and stiffness, make them highly attractive for potential improvement of mechanical properties of structural materials. The aim of this research is to investigate experimentally the effect of coated nano-composite with different concentrations on fatigue life behaviour of carbon steel specimens with 0.3 μm surface finish. Nano-adhesives of epoxy resin are synthesized and evaluated. They are modified by multi walled carbon nanotubes (MWCNT) (0.3 wt.- %, 0.5 wt.- %, 0.7 wt.- %) as reinforcement. Fatigue tests are conducted on specimens using a rotating bending machine of the cantilever type to evaluate the fatigue strength and these are compared with them obtained for the neat material. By comparing the results of specimens coated with different concentrations of MWCNT-epoxy composition with the base materials, it is found that 0.5 wt.- % of MWCNT composition is the best selection for specimens having 0.3 μm roughness. As compared to the base materials, the fatigue life increased by 383 %, 785 %, 1239 %, and 800 % by coating with neat epoxy as well as with 0.3 wt.- %, 0.5 wt.- %, and 0.7 wt.- % MWCNT-epoxy, respectively.

Short Crack Growth Behavior in Ferrite-Bainite Dual Phase Steels

The effect of bainite content on the short crack growth behavior of three ferrite bainite dual phase steels has been examined using a rotating bending machine together with examinations of the microstructural constituents associated with the fatigue crack path. The magnitude of ΔKthsc for ferrite bainite dual phase steels, in general, is found to increase with increasing amount of bainite. Critical examinations of the crack paths indicate that it is inter-granular for steels with < 70% bainite while it is intra-granular for steels containing > 70% bainite.

Research on Residual Stress for Hull Plate in Cold Forming

Based on the mechanical analysis of the plate formed under pure bending, we developed the theoretical model of residual stress distribution pattern under single curvature cold-forming. The numerical method is used to simulate the forming procedure of The 3-d surface ship CNC bending machine, which help us acquire the stress and strain distribution of cold formed component and the relationship between steel plate thickness and its peak value of residual stress. The results show that the simulation model makes accurate prediction of the residual stress. The peak value of residual stress increases with the increase of plate thickness, and it decreases with the increase of bend radius.

Effect of Material Properties on Cross-Section Deformation during Bending an Aluminum Extruded Section

The cross-section shape change was investigated to determine the effects of proof stress, r value, wall thickness, and cross section in push-through bending of a square extruded pipe. Extruded A6063 aluminium alloy (40×40×2.0 mm) was used in the experiment. The push-through bending machine used has a six-axis NC controller. In this study, a two-dimensional single curvature shape was adopted in order to investigate the fundamental bending properties. A high-proof-stress material with severe bending workability was examined in this experiment to clarify the effect of bending workability on the material properties. Workability was evaluated by examining wrinkles and shape change of the cross section; the change in thickness was also evaluated, as were n and r values. The results are as follows. The high-proof-stress material was bent, resulting in significant cross-section deformation. The size of wrinkles caused by bending increased due to the large bending radius, and the wrinkles produced were deep. The effect of the r value on the cross-section deformation after bending could not be determined. In the present experiment range, the bending limit was determined by the size of wrinkles in internal bending. In A6063-T1, the wall thickness had a significant effect, and the forming limit of the thin-walled material was low. The bending limit was low for A6063-T5, and the effect of the wall thickness was slight. The bending limit of a 60×60mm cross-section piece was considerably lower than that of a 40×40 mm cross-section piece, for the same wall thickness; it was particularly significant in A6063-T5.

Square Head Adjustable Die Device Research on Ship 3D CNC Forming Machine

Research device structure upon suppressing impress and wrinkling about three-dimensional numerical control bending machine.3D ship curved-surface outside plate automatic forming process is always the difficult part in the field of domestic and international shipbuilding. Analyzing the problems in existing processing methods ,for example, line heating technology has the defects of poor production conditions, large labor intensity, not environmental friendly and cold bending forming method may result in indentation, wrinkling or rebound phenomenon.Presents the forming process of a ship hull plate based on square head adjustable die curved surface forming device. By setting the non pressure and a plurality of planar head to replace the traditional integral die method, the paper will illustrate the composition and working principles of the process at the same time try to implement effective control of indentation and wrinkle phenomenon followed by verification through experiments.

Research on Repairing Deformation Rapidly for Steel Strip

This article studied about bending machine, adopted converse thinking for designing, transformed the bending machine then designed steel strip straightening machine, using this machine to make the deformed steel strip straighten. We used the 3 d modeling software SolidWorks to make a 3d model for the machine, then used the add-in cosmosworks of SolidWorks to make a simulation for main part, got the curve of stress, strain, and displacement of the part and provided a reference for the transformation of steel strip straightening machine.

Development of the Soft Pipe Bending Machine with Thickness Guarantee

A Soft bending pipe is widely used for freezing equipment and shipbuilding. This pipe has some problems such that outside wrinkle, crack, phenomenon of thinning wall. However, the bending machine that can completely solve the problems is not yet. In this study, we have manufactured the self-made mandrel to guarantee both roundness and thickness of the pipe in the bending process for a soft pipe such as a copper pipe. The mandrel consisted of a ball, stick and connection pin. Also, we have manufactured the bending machine that can decrease friction between the pipe and the bending die. The experiment was tried to verify the performance of the mandrel and the pusher to the thickness guarantee of the pipe.

State of the Art: Prototyping of the Roll Bending Machine

This paper focuses on the development of a new type of roll bending machine. Our primary aim was to build a machine that could form ultra-high-strength steels (UHS) with smaller inner radii than those achieved by traditional bending methods. One of the main planning principles was modular construction, so a length of a bending line could be easily selected or changed later by the user without major changes to the basic construction of the machine. In contrast, in traditional roll forming, the blank does not move during the forming process, so the accuracy of the profile can be better controlled. Different kinds of cut to size-open profiles can be produced by this machine, which utilizes and combines bending and rolling techniques. In the initial stages of the project, the needs of smaller companies that do short-run productions are taken into account. First, the prototype is designed mainly for research use; moreover, it is important that the properties of the machine are multifunctional. In addition, forming can be done in several ways by this machine. In this paper, there is shown creation of a machine, designing of construction and manufacturing steps of the whole machine including assembling. Also detailed description of the various functional components and the operating principle is presented. The results of the forming tests are also presented.

Stored Energy of Plastic Deformation in Tube Bending Processes

The paper presents an aproximate analytic method for determination of the stored energy of plastic deformation during cold bending of metal tubes at bending machines. Calculations were performed for outer points of the tube layers subjected to tension and compression (the points of maximum strains). The percentage of stored energy related to the plastic strain work was determined and the results were presented in graphs. The influence and importance of the stored energy of plastic deformation on the service life of pipeline bends are discussed.

Experimental and Numerical Study on Dieless Bending of 2-Piece Parallel Flow Microchannel Heat Exchanger

Parallel flow microchannel heat exchangers have been increasingly applied in HVAC (Heating, Ventilation and Air Conditioning) field due to their characteristics, such as high efficient heat transfer performance, compact form and low cost. Production rationalization of the heat exchanger is required for realization of a competitive, light-weight and easy-to-assemble product. The heat exchanger is usually bent to L-shape so as to decrease the volume of air conditioner. To correspond with design changes for multi-generation use and to achieve good forming quality, a dieless forming technique is developed to offer flexible manufacturing. Using this method, heat exchangers can be formed with variable bending radius conveniently, which can reduce the mold cost and obtain high productivity. Meanwhile, product defects such as fin damage can also be reduced because there is no physical contact against tools in the bending portion. In the present study, the forming principle of dieless bending process is first stated by theoretical analysis. Then to verify the proposed forming mechanism, a NC dieless bending machine is manufactured to implement the bending experiment. Finally, based on the verified FE model, the bending process for the 2-piece heat exchanger has been improved. As a result, the dieless bending process has been successfully developed and can be applied to produce square-shape heat exchanger with variable bending radius.

Operation of an extension and bending machine in scale removal from hot-rolled strip

Statistical analysis of the operation of an extension and bending machine in scale removal from hot-rolled strip provides the basis for a construction of a mathematical model by logit regression, in which the tensile energy of the strip in the standard range is related to a controllable characteristic—the total overlap of the working rollers in the machine with natural variation in strip thickness and width. The model may be used to maintain stable operation of the extension and bending machine with regulation of the drive’s load over a specified range. Prospectively, it may be used to determine the rational overlap of the machine’s working rollers with modification of the extension and bending mechanism or the cross section and properties of the machined strip.

Influence of Parameters in Coupled Adaptive Self-Organizing Sliding-Mode Fuzzy Controller Using Volumetric Type Bending Machine

The dual-axial volumetric type bending machine is a coupled system and has significant structural interaction. Fuzzy controllers are widely applied in electro-hydraulic servo control systems. This paper proposes a coupled adaptive self-organizing sliding-mode fuzzy controller (ASOSMFC) to improve its level control performance. Parameters are important factor to the control effect. Experimented results indicate that owing to the unsymmetry of two subsystems of volumetric type bending machine, the adaptation gains of two subsystems must be different, to prevent the system divergent adaptation gains must be positive. Sliding plane gain will influence time response, synchronism and oscillation in steady state.

Simulation on Rigid-Flexible Coupling of Rotary Bending Machine

Simulation on Rigid-Flexible Coupling of Rotary Bending Machine

Simulation Experiment of Roll Bending Machine in Valveless Servo System

Valveless servo system is a new technology which is widely used in recent years. Compared to the traditional hydraulic system, valveless servo system has a lot of advantages such as high efficiency, less pollution and saving energy, which will be the main research direction of the hydraulic control in the future. Roll bending machine is a large industrial machine, but the efficiency of existing hydraulic system of roll bending machine is low and the cost of maintenance management is high. Applying valveless system on roll bending machine can overcome these defects. This paper made a study of the control strategies which were about valveless servo system on roll bending machine. And software MATLAB was used to do simulation experiment on valveless servo system. This paper summarized the steady-state error and dynamic characteristics according to output signals in different input signals.

High Efficiency LED Module with 3D Bending Machine

Abstract- In this paper, a bending machine for tuning optical design of LED module is proposed. The tuning is done by changing the bending angles of each package on a given module with the help of automatic control program. Luminous intensity distribution can be controlled by adjusting the light emission path, which in turn can be implemented as changing the bending angles of individual LED packages on the module. The proposed machine is capable of bending packages to specified angles with errors less than 0.1°. Three-dimensional light distribution for bent package LED modules is also studied based on various application scenarios so that each scenario can have diversified luminous intensity distribution resulting in higher uniformity and better luminance quality. The machine has several advantages, including quick bending, high accuracy, and great customizability. These advantages make the machine meet the requirements of automatic mold forming.

Design and realization of a multisamples rotating high cycle fatigue machine

In this work the design and the technical characteristic of a Moore rotating bending machine are presented. The machine has been realized at the University of Cassino in order to run tests on multiple specimens at different temperature. The user can choose independently the load and the temperature for each specimen. The machine has been designed to produce in short time a several numbers of data of materials fatigue strength at low costs. The machine is in assembling step at the Laboratory of Industrial Design of the University of Cassino.

3D Tube Forming and Applications of a New Bending Machine with Hydraulic Parallel Kinematics

This research presents a new versatile bending machine and its practical applications. The proposed machine uses a new method. When tubes are fed into the fixed and mobile dies, they are bent by shifting the relative position of the mobile die. The bending radius is controlled by the relative distance and orientation between the mobile die and the tube. The bending angle is controlled by the length of the fed tube. This forming process has a big advantage. A change in the expected bending shape will need no change in the tooling system but only a new definition of the motion of the active die and the length of the fed tube. Active die movements are controlled by a 6-DOF Parallel KinematicsMechanism (PKM) with a hydraulic servo drive. Making use of the hydraulic PKM serves not only to achieve a complete motion along six axes but also to obtain the high dynamic motion of the bending machine. Application examples show that the bending machine can be applied to a designer’s furniture and universal designed products. Until now, these processes have been difficult to achieve using a conventional bending machine.

Multi-Angle Bending Machine for Creating High Luminance Efficiency LED Module with Diversified Light Distribution Curve

In this paper, a bending machine for tuning the optical design of an LED module is proposed. The tuning is done by changing, with the help of an automatic control program, the angle at which each package on a given module is bent. The distribution of luminous intensity can be controlled by adjusting the light emission path, which in turn can be implemented by changing the angles of individual LED packages on the module. The proposed machine is capable of bending packages to specified angles with less than 0.1° of error. Three-dimensional light distribution for bent package LED modules is also studied, based on various application scenarios, so that each scenario can have a diversified luminous intensity distribution, resulting in higher uniformity and better quality luminance. The machine has several advantages, including quick bending, high accuracy, and great customizability. With these advantages, the machine meets the requirements of automatic mold forming.