Bending Machine Research Articles

In-Process Monitoring of Springback in Industrial Bending Using a Laser Sensor-Based Method

Bent tubes and profiles are widely used in many industries such as automotive, aerospace and shipbuilding. In bending of tubes and profiles, springback is normally regarded as a challenge, affecting the dimensional accuracy of products. Springback control significantly determines the production route of products, including logistics. At present, effective in-situ measurement methods are lacking. This makes it difficult to realize in-process, closed-loop control of springback for improving product quality and productivity, while putting improved flexibility on the production route. In this research, an in-process measurement technique for monitoring springback in rotary draw bending was developed. A device with a laser transmitter and receiver was installed on a bending machine to detect displacement changes of the part after being released from the tool. The displacement information was collected by a controller that shows the measured displacement. A series of tube bending experiments together with the developed in-line laser sensor measurement and conventional off-line manual measurements were carried out. The result shows that the in-line laser sensor method provides a good capability for springback measurement. Since the laser measurement method is done with no need to remove the workpiece from the tooling system, it facilitates developing an in-process compensation strategy to control springback.

Deployment of a deep-learning based multi-view stereo approach for measurement of ship shell plates

In this work, a measurement system integrated with a deep-learning based multi-view stereo (MVS) approach is developed to measure ship shell plates. Specifically, a deep learning architecture of CasMVSNet is deployed for depth map inference from multi-view images, which can remarkably decrease the dense reconstruction time and GPU memory consumption. This is the first report that a learned MVS architecture is deployed to three-dimensional (3D) reconstruction of ship shell plates. Measurement experiments are then performed for three typical hull plates to evaluate the accuracy, efficiency and completeness of the proposed measurement method. The results suggest that the complete point cloud data of the curved hull plates can be reconstructed in about 3 min with the average of errors less than 1 mm, which fulfills the requirements of precision and efficiency in shipbuilding production. Compared with traditional wooden templates, the proposed measurement method is more accurate, efficient and inexpensive. The developed measurement system with quantitative data can also be readily integrated with the 3D computer numerical control (CNC) plate bending machine. Moreover, the robustness and flexibility of the proposed measurement method have been verified by comparison with the measurement method based on active binocular stereovision.

Modelling of the sheet forming while 3-roller bending process

3-roller bending process was investigated using physical modelling and computer simulation. Main technological parameters influence on the formation of tube billet diameter are present; these main technological parameters are upper roller displacement and distance between axes of bearing rollers. Complete factorial experiment was conducted using bending machine, radius of the produced tube billet was set as response function. Conditions for conducting the complete factorial experiment using bending machine and techniques of tube billet radius estimation by graphical-analytical method are presented. At that least square method and SolidWorks software were applied. Regression equations for calculating tube billet diameter conditionally upper roller displacement and distance between axes of bearing rollers were obtained. Influence of these two factors on tube billet radius formation was demonstrated. Finite element method (FEM) computer simulation of the forming process was done with respect to parameters corresponding to parameters of physical modelling experiment using bending machine. FEM computer simulation was done using QForm software. QForm simulation was realized for elastic-plastic bending in terms of two-dimensional deformation. Point tracking was applied to calculate coordinates of the points of the formed sheet and bending parameters. It allowed estimation of the neutral line location in the formed sheet when bending stage was finished. Presented results of computer simulation are figures with trajectories of the tracked points; figures illustrating changing of distance between tracked points; graph of accumulated strain changing through sheet’s thickness. New criterion for neutral line (neutral surface) was proposed for sheet bending process. Results of the research can be effective when exploring Heausler AG bending equipment.

3D Pipe Forming of a New Bending Machine with a 3PUU–3RPS Hybrid Mechanism

To achieve the spatial variable curvature bending process of metal pipes, one 3PUU–3RPS hybrid mechanism designed for the free-bending forming of pipes is presented in this study. Its kinematics model was conducted based on theoretical analysis, and the obtained result was validated through ADAMS simulation. Through the theoretical analysis, the inverse position model of the proposed mechanical construction, which can show the relationship between the motion and the drive of the working platform, was presented. The velocity Jacobian matrix was also obtained and analyzed by establishing the inverse velocity model and inverse acceleration model. In addition, the static stiffness analysis of the proposed mechanical construction was also conducted in ABAQUS. Finally, by investigating its working space, the capability of 3PUU–3RPS mechanism was proved.

Damping oscillations in a wire bending process

This paper presents an approach to modify CAD/CAM generated motion profiles for wire bending machines, in order to damp wire oscillations without decreasing machine throughput. Two different methodologies are presented, both leveraging on a simple and easily identifiable model of wire oscillations, the first one based on a filtering approach, the second one on an optimisation approach. The two methodologies are both characterised by a low computational complexity, allowing them to be integrated directly in the bending machine user interface, and can rely on a standard camera to identify wire oscillation parameters. A thorough experimental validation of the approaches is also presented, showing promising results in damping oscillations with wires of different materials.

Performance Testing and Preventive Maintenance of Roller Bending Machine Using the ISMO Method

Performance Testing and Preventive Maintenance of Roller Bending Machine Using the ISMO Method

SEMI-AUTOMATIC QUARTZ TUBE BENDING MACHINE

The article presents the assembly of a semi-automatic quartz bulb bending machine for the production of bactericidal ultraviolet lamps. The standard methods of production and testing of quartz flask bending machines were analyzed in the work. In the course of work and on the basis of the conducted research, the technical characteristics and equipment configuration were worked out. The bending machine includes a block for bending quartz tubes with a diameter of 19 mm and a block for bending quartz tubes with a diameter of 28 mm. Quartz tubes are installed on the ma-chine and removed manually. The bending process is automatic. The bending machine allows you to bend quartz tubes of different lengths and with different bending radii. The control and automation of the bending machine is developed on the basis of the COMAT Boxx controller installed in-side the control cabinet.

Recycling of Carbon Fiber Laminates by Thermo-mechanical Disassembly and Hybrid Panel Compression Molding

An innovative recycling process for thermoset composite laminates is proposed by thermo-mechanical disassembly and further compression molding of hybrid thermoformable composite plates. Due to the thermo-mechanical process, single cured plies are extracted from the waste laminate. Subsequently re-lamination is performed by interposing thermoplastic films between the reclaimed composite plies. Final consolidation is carried out by compression molding. In order to show the feasibility of the novel recycling technology, carbon fiber reinforced composite plates by autoclave molding were thermo-mechanically disassembled in a manual roll bending machine after heating in oven. Reclaimed cured plies were laminated by alternating thermoplastic interlayers made of low density polyethylene. The hybrid laminate was consolidated at the temperature of 220�C and the holding pressure of 38.5 bar. Results from bending tests on virgin and recycled plates showed the very good agglomeration of the hybrid samples and the optimal preservation of performances of initial cured plies of the virgin material into the recycled plate.

Experimental Investigation on Flexural Capacity of Reinforced Concrete Beams Strengthened with 3D-Fiberglass, CFRP and GFRP

The main objective of this study is to investigate the structural performance of reinforced concrete (RC) beam specimens strengthened with 3D-fiberglass as compared with fiber-reinforced polymers (FRP) sheets. For this purpose, six RC beams were fabricated, strengthened, and tested under a four-point bending machine. One of the beams served as the control beam (REF), while the others were strengthened with carbon FRP (RCFRP), glass FRP (RGFRP), 3D-fiberglass and epoxy resin (R3DTR), 3D-fiberglass and epoxy resin extended to the sides (R3DTRB), and 3D-fiberglass and concrete repair (R3DTG). Failure mode, crack development, flexural capacity, ductility, the effectiveness of wrapping configurations, and the performance of epoxy resin in comparison with concrete repairer were studied between various beams. The results attest to the better performance and effectiveness of 3D-fiberglass over FRP in terms of flexural capacity, crack pattern, and ductility. The R3DTR and RGFRP specimens, compared to the control specimen, had the highest and lowest flexural capacity growth, with 19% and 8.4%, respectively. In addition, the failure modes observed in this study were in good agreement with the failure modes present in ACI.440.2R-17. Moreover, finite element (FE) models were proposed to predict the residual capacity of the specimens strengthened with FRP, using Abaqus software.

Design Development of Punching and Bending Machine Combination

This paper purpose is to study working pressure limit of the machine combination between blanking and punching process. The combination punch and bending machine in this study is a machine that belongs to the press type with the use of punch and die. This machine has a hydraulic drive with a maximum pressure generated of 700 bars. The engine performance is only able to withstand a working pressure of 27.7 bars. Therefore, the utilization of the working pressure must be increased to maximize the working pressure. The analysis was carried out on the machine with two methods, namely simulation and experiment. The simulation method was carried out using Autodesk Inventor software to design and simulate in order to find out the critical points that occur on the machine. It was given working pressure according to the permitted safety factor of 1.5. The experimental method was carried out by measuring the voltage using a Strain gauge sensor positioned at the critical point obtained in the simulation and measuring the deflection using a dial indicator. From these tests, it was found that the initial working pressure before being optimized was 27.7 bars to 49.5 bars after being optimized.

Automatic computation of bending sequences for wire bending machines

ABSTRACT Determining a feasible bending sequence, i.e., ensuring absence of wire self-collisions and wire-machine collisions, or even an optimal bending sequence, i.e., minimising time or energy required to perform it, is a difficult and time-consuming task for complex workpieces, even for expert operators. Introducting algorithms for the computation of wire-bending sequences is thus crucial to increase productivity and production flexibility, and to decrease production costs. This work proposes an algorithm to automatically determine an appropriate bending sequence for a given workpiece, bending tool, and machine 3D CAD model, which leverages on a representation of the wire as a robotic manipulator and of a bending sequence as a tree, and on the adoption of A* as graph search algorithm. A cost and a heuristic function, suitable for the wire-bending problem, and an approach to parallelise the execution of A* are introduced, as well. In this way, a computationally simple and efficient wire-bending sequence computation algorithm is devised, able to determine a solution in an amount of time less or equal to the time used by an expert operator, without the need of high computational power. The effectiveness of this algorithm is assessed on two different test cases, relevant to industrial workpieces.

Fatigue life enhancement of additive manufactured 316l stainless steel by LSP using a DPSS laser system

ABSTRACT Present work aims to study the fatigue life behaviour of additively manufactured (AM) stainless steel 316L in a laser shock peening (LSP) process. The fatigue behaviour of as-built samples and LSPeened sample were studied on the AM samples. A new diode-pumped laser system was utilized as an instrument to perform LSP operations. LSP operation was performed under two different sacrificial layers of different materials i.e. vinyl tape and aluminium tape. The other essential LSP parameters, namely energy, pulse width, spot size, overlap, and number of layers were kept constant based on the previous experimental findings. The characterization was done for analyzing the residual stresses using a hole drilling process, and a 4-point bending machine. A considerable improvement in compressive residual stress and fatigue life was observed in the LSPeened samples. Such improvements in residual stresses and fatigue life may pave a road to establishing diode-pumped lasers for LSP applications.

The deformation behaviour of electrodeposited nanocrystalline Ni in an atomic force microscope with a newly developed in situ bending machine

Abstract Four-point-bending and strain-controlled fatigue experiments were performed on electrodeposited nanocrystalline nickel specimens at room temperature. For the first time, the deformation behaviour of bulk nanonickel specimens was studied in an atomic force microscope with a newly developed in situ bending machine. Results show that grain boundary sliding plays an important role during deformation, and the fatigue crack propagates along grain boundaries.

Development of a carbon nanofiber-attached flexible piezoelectric nanocomposite towards self-powered wearable devices

The flexible piezoelectric nanocomposite (PNC) has the tremendous opportunity in wearable and foldable devices for healthcare detection, artificial skin, human body motion, and robotics applications. The aim of this paper was to develop the polymer based piezoelectric nanocomposite using cast solution method, the carbon nanofiber (CNF) was mixed with poly(vinylidenefluoride) (PVDF) polymer as a solvent, to make a series of flexible piezoelectric nanocomposite (PNC) out of PVDF/CNF and investigate their dielectric characteristics across a frequency range of 20 Hz to 10 MHz. Moreover, the piezoelectric performance of PNCs is examined by bending machine with sufficient bending cycles. The dielectric properties of PNCs were analyzed using the impedance analyzer for the varying wt% of CNF. It was discovered that the 2 %wt CNF based PNC showed excellent dielectric properties and maximum piezoelectric voltage of 0.62 V at bending strain of 0.009. These fabricated PNCs can be used for piezoelectric nanogenerator for self-powered and wearable sensors.

Finite Element Study on Forming Helical Springs by Wire Bending with a Plate

Coil springs, widely used as mechanical elements, will enter another new production outlook due to the application of CNC wire bending machines and as the era of On-Demand Manufacturing is approaching. This article tries to follow the trend and use finite element analysis investigating parameters, such as the angle, shift distance, and wire diameter, applied in a CNC bending machine with a swivel plate as the die on the formed cylindrical helical coil springs. The results show that the angle of the swivel plate normal to the wire feeding direction and shift distance have a significant effect on the spring diameter, while the wire diameter has a significant effect on the spring pitch. The result will be used as a reference for the industry to develop On-Demand Manufacturing machinery applications in the future.

Offline digital twin synchronization using measurement data and machine learning methods

Digital Twins play an important role in modeling production processes to adapt parameters according to predicted situations. Panel bending machines from Salvagnini use this technology to ensure safe operating conditions and to guarantee accurate results for different settings, even with highly variable material properties. Due to constantly increasing accuracy requirements, digital twins have to increase accuracy on the one hand and adapt to new machine generations on the other hand. This work shows how machine learning tools can be used to synchronize digital twins accurately and efficiently with real-world behavior by learning parameter values with measurement data while maintaining interpretable and robust analytical models.

Comparison of the cyclic fatigue resistance of One Curve, F6 Skytaper, Protaper Next, and Hyflex CM endodontic files.

ObjectivesThis study compared the cyclic fatigue resistance of One Curve (C wire) and F6 Skytaper (conventional austenite nickel-titanium [NiTi]), and 2 instruments with thermo-mechanically treated NiTi: Protaper Next X2 (M wire) and Hyflex CM (CM wire).Materials and MethodsTen new instruments of each group (size: 0.25 mm, 6% taper in the 3 mm tip region) were tested using a rotary bending machine with a 60° curvature angle and a 5 mm curvature radius, at room temperature. The number of cycles until fracture was recorded. The length of the fractured instruments was measured. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). The data were analyzed using one-way analysis of variance and the post hoc Tukey test. The significance level was set at 0.05.ResultsAt 60°, One Curve, F6 Skytaper and Hyflex CM had significantly longer fatigue lives than Protaper Next X2 (p < 0.05). No statistically significant differences were found in the cyclic fatigue lives of One Curve, F6 Skytaper, and Hyflex CM (p > 0.05). SEM images of the fracture surfaces of the different instruments showed typical features of fatigue failure.ConclusionsWithin the conditions of this study, at 60° and with a 5 mm curvature radius, the cyclic fatigue life of One Curve was not significantly different from those of F6 Skytaper and Hyflex CM. The cyclic fatigue lives of these 3 instruments were statistically significantly longer than that of Protaper Next.

Improvement of 3D-simulation models based on experiments

The accuracy of manufacturing machines and specially the products of automatic panel benders is continuously improving. Within the last ten years the permissible deviations of the bending angles have been reduced in the specification by 50%, from 1.0° to 0.5°. This accuracy is to be achieved from the first performed bend. In order to further improve and shorten the design process, a parameter identification is carried out based on measurements on the real machine. A good pre-adjustment and tuning of the developed digital twin with respect to the bending process of various sheet metals with a large variety of operating parameters has been derived. In this contribution it is shown how the computation results of the highly efficient 3D-FEM simulation models are matched with the real bending machine in order to derive further improvements.

WORK ANALYSIS OF PLATE BENDING WORKSHOP IN SHIPBUILDING INDUSTRY

Plate bending is one of the major processes in shipbuilding. The plates which are cut in specific dimensions are sent to plate bending work shop and they are curved by using various methods. These curved plates constitute bilge turn plates of a vessel which are curvilinear. In this study, plate bending work shop was considered and its simulation model was created by using SIMIO software. The aim of the study is to see the effects of some alterations on available situation of plate bending work shop and present some recommendations in order for the plate bending work shop to operate effectively. In this work, there are number of four alterations including the changing of bending processing time, number of cranes and bending machine. At the end of the study, the values of the most suitable crane number, bending machine number, and the bending operation processing time were recommended. It is believed that the plate bending work shop will operate in effective way if the shipyard administration implement the recommendations presented in this study.

Assembly of a semi-automatic quartz tube bending machine for the production of ultraviolet radiation sources

Presented is the assembly of a semi-automatic quartz tube bending machine for the production of bactericidal ultraviolet lamps. The standard methods of production and testing of quartz tube bending machines were analyzed. On the basis of the conducted research, the technical characteristics and equipment configuration were worked out.