Shape Of Seam Research Articles

Development of a 3D Virtual Welding Simulator Using Weld Bead Created by Voxelization Technique

In this study, we developed and implemented a cost-reducing, real-time virtual welding simulator to train welder candidates. In order to make a real-time welding simulation, a three-dimensional weld bead form was designed. We used a parabola as the basic bead slice shape, considering the similarity between the parabola and the bead slice. During the welding process, the parameters of the weld bead shape are calculated at each time step using an artificial neural network. This network determines the shape of the weld bead and the depth of penetration, based on inputs received from the sensor device that tracks the motions of the torch. After the parabola’s parameters have been determined, the voxel map and corresponding hash-based octree data structure are generated in real-time. By using the voxelized data, a weld bead isosurface consisting of triangles is reconstructed with a marching cubes algorithm allowing us to generate more realistic weld seam shapes. We used multi-threaded programming for voxelization and isosurface extraction to reduce the computation cost on high-resolution virtual scenes. The isosurface extraction times for different thread counts and also a feature comparison with other simulators in the literature are shown in this paper.

Tailored laser beam shapes for welding of copper using green laser radiation

AbstractThe rapid development of laser beam sources and adapted welding technologies in recent years lead to an increased use of laser welding techniques in automated production nowadays. Especially its precision and local energy input are key features for joining applications in electric vehicle components, where joints have to meet both mechanical and electrical requirements as current-carrying connections. However, the copper materials used are difficult to weld due to their physical properties, making a stable process with fewest seam imperfections only feasible within a limited process window. Recently available beam sources emitting visible laser radiation have proven to overcome the low absorptivity at process start, but spattering is still a prone defect significantly affecting process efficiency and quality. Literature approaches for modifying the energy input point to laser beam shaping as a method for reducing process imperfections, which, however, has not been extensively researched in copper processing using green laser radiation.Thus, this study investigates the influence of a shaped intensity profile for visible laser radiation created with a reflective diffractive optical element in laser beam welding with laser powers up to 3 kW. A characterization of the process dynamics is performed by use of high-speed imaging, and metallographic analysis is used to elaborate benefits of the applied beam shapes. With beam shaping, an enlarged heat conduction welding regime and an advantageous seam shape are found. Furthermore, a decrease in spatter formation during deep penetration welding is detected for the elliptical beam profile, which correlates with an oscillation movement of the capillary.

Quantitative analysis of 3D seam shape according to easing conditions for efficient sewing using muslin

This study quantitatively analyzes the data of 3D seam shapes that alter according to easing conditions. By numerically approaching easing, which is only taught using traditional methods, this study suggests a method of analyzing the changes in 3D surface area, volume, and seam shape. The 3D data of the completed samples were obtained through a 3D scanner, the solid shapes were analyzed using reverse engineering, and a new program was developed. The shape, area, and volume of the data were analyzed, and the deformation rate was measured using the radius of curvature. Linear seam lines were bent because of the mechanical pushing inflicted by the garment with easing. The area increased dramatically as the ease amount increased when the seam lines were short, whereas it was relatively unaffected when seam lines were long. The radii of curvature for curved seam lines show that, for all samples, the waveform is high at the center where the seam is. The peak value did not increase for curved seams when the ease amount increased. The sum of the areas increased with a larger radius of curvature for the curved seams. It is a crucial reference for easing in garments regarding quantitative changes in seam shapes and volumes according to easing type and amount.

Selection of Parameters for Optimized WAAM Structures for Civil Engineering Applications.

Using the CMT (Cold Metal Transfer, F. Fronius, Upper Austria) welding process, wire arc additive manufacturing (WAAM) enables companies to fabricate steel components in a resource-saving manner (additive vs. subtractive) by properly reinforcing existing steel components. Two fundamental questions are discussed in the current work. The first focus is on the general geometric possibilities offered by this process. The influence of various parameters, such as wire feed speed, travel speed, and torch inclination on the seam shape and build-up rate are presented. The microstructure of the manufactured components is evaluated through metallography and hardness testing. Based on the first results, print strategies are developed for different requirements. Moreover, suitable process parameter sets are recommended in terms of energy input per unit length, weld integrity and hardness distribution. The second focus is on testing and determining joint properties by analyzing the microhardness of the welded structures. The chosen parameter sets will be investigated, and steel quality equivalents according to ÖNORM EN ISO 18265 will be defined.

Keyhole-in-keyhole formation by adding a coaxially superimposed single-mode laser beam in disk laser deep penetration welding

Laser deep penetration welding is characterized by the formation of a vapor capillary (keyhole) and a high overall absorption (coupling rate) of the laser radiation in comparison to heat conduction welding. Due to multiple reflexions within the highly dynamic keyhole, the absorption mechanisms are very complex. The questions, how a laser beam interacts with the existing keyhole, and, if shadowing effects occur, are a matter of concern for several researchers. In this study, the hypothesis that the beam of a laser source can be transmitted to a significant extent through an existing keyhole and acts predominantly at the keyhole bottom was investigated. Experiments were carried out on mild steel and technical pure aluminum, using a specially designed optical system, which allows to coaxially combine two laser beams and to adjust their settings like the energy and the focal plane individually. A combination of a disk laser with a focal diameter of 390 µm and a single-mode fiber laser with a focal diameter of 30 µm was used. Weld depths and seam shapes were analyzed in cross and longitudinal sections. Based on the results, it is shown that the much smaller focal diameter of the single-mode laser beam acted at the bottom of the keyhole and caused a kind of “keyhole-in-keyhole formation” in the form of a local maximum in weld depth whose expression depended on the focal plane of the single-mode laser beam.

GAN-Based Image Dehazing for Intelligent Weld Shape Classification and Tracing Using Deep Learning

Weld seam identification with industrial robots is a difficult task since it requires manual edge recognition and traditional image processing approaches, which take time. Furthermore, noises such as arc light, weld fumes, and different backgrounds have a significant impact on traditional weld seam identification. To solve these issues, deep learning-based object detection is used to distinguish distinct weld seam shapes in the presence of weld fumes, simulating real-world industrial welding settings. Genetic algorithm-based state-of-the-art object detection models such as Scaled YOLOv4 (You Only Look Once), YOLO DarkNet, and YOLOv5 are used in this work. To support actual welding, the aforementioned architecture is trained with 2286 real weld pieces made of mild steel and aluminum plates. To improve weld detection, the welding fumes are denoised using the generative adversarial network (GAN) and compared with dark channel prior (DCP) approach. Then, to discover the distinct weld seams, a contour detection method was applied, and an artificial neural network (ANN) was used to convert the pixel values into robot coordinates. Finally, distinct weld shape coordinates are provided to the TAL BRABO manipulator for tracing the shapes recognized using an eye-to-hand robotic camera setup. Peak signal-to-noise ratio, the structural similarity index, mean square error, and the naturalness image quality evaluator score are the dehazing metrics utilized for evaluation. For each test scenario, detection parameters such as precision, recall, mean average precision (mAP), loss, and inference speed values are compared. Weld shapes are recognized with 95% accuracy using YOLOv5 in both normal and post-fume removal settings. It was observed that the robot is able to trace the weld seam more precisely.

Study of weld pool monitoring system based on spatial filtering

The observable information of the welding process mainly includes the weld pool, weld seam, and arc length, which can be used to predict the penetration depth, perform weld tracking, and provide early warning of weld defects. Welding monitoring technology based on machine vision has been widely researched to improve the quality and efficiency of welding. This paper proposes a novel weld pool image acquisition system based on spatial filtering and Abbe’s theory of image formation. A high-pass spatial filter was designed to eliminate the low frequency background noise so that the contour of the weld pool, weld seam, and arc shape were acquired. Compared with the weld pool monitoring system based on an optical filter, this method more effectively solved the problem of the large radiation gradient in the weld pool area, and the weld pool could be more clearly observed. It provided a new method to image the weld pool image system with the advantages of low cost and ease of implementation.

Pitching trajectory and simulation of a baseball ball with an IoT ball

Recent research on baseballs has revealed that the pitching trajectory varies with speed, number of rotations, degree of rotational axis and seam shape on the ball surface. Therefore, a pitching experiment was conducted to clarify the effects of ball inclination, velocity and number of rotations on the ball's trajectory. The pitching experiment was conducted by 12 pitchers from the university's baseball club.IoT balls were used to measure speed, number of revolutions and ball tilt.Pitchi a ball was used to capture images of the ball with a high-speed camera. The coefficient of lift and coefficient of drag during pitching were also measured by hydrodynamic force experiments. In the hydrodynamic force experiment, measurements of one-seam, two-seam and four-seam were carried out to check the differences between the seams. The results showed that the pitching trajectory changed laterally depending on the degree of rotation axis. Furthermore, changes in the coefficient of lift and coefficient of drag for 1-seam, 2-seam and 4-seam balls were found to vary with the degree of rotation.

Seam Formation in Laser Beam Micro-Welding with Spatial Power Modulation

When laser sources of high brilliance are used for the micro-welding of metals, small seam dimensions are generated. If the spatial power is modulated by a superposition of the linear feed rate and a circular-oscillatory movement of high frequency, the width of the seam is controlled by the amplitude of the circular movement. In this study, the irradiation pattern of the seam was calculated and reveals that some spots of the seam area are not irradiated, while other have been irradiated several times. The seam shapes were visualized with micro cross-sections for different laser powers, linear feed rates and oscillatory amplitudes. Thermal simulations were made to discuss the different seam shapes. A consequence of the oscillatory movement is the appearance of different solidification fronts, which are visible in the micro cross-sections.

The Preliminary Exploration of Micro-Friction Stir Welding Process and Material Flow of Copper and Brass Ultra-Thin Sheets.

In the friction stir welding (FSW) of ultra-thin dissimilar metal sheets, different physical material properties, the reduction of plastic metal in the weld zone, and insufficient plastic metal flow lead to poor weld seam shapes and joint qualities. Therefore, it is necessary to study the flow behavior during the FSW of ultrathin sheets. In this study, micro friction stir welding (μFSW) was conducted and analyzed for the butt welding of 0.6-mm-thick ultrathin brass (H62-H) and pure copper (T2-Y) sheets. By analyzing the electric signals of the temperature and force during the welding process, testing the mechanical properties, and analyzing the metallography of the joint, the influences of the process parameters on the metal flow behavior during μFSW were studied. In the proper process conditions, the material preferentially migrated and concentric vortex flow occurred in the vicinity of the shoulder and tool pin action areas. The copper was pushed from the retreating side (RS) to the advancing side (AS) of the weld, allowing it to flow more fully. A mixture of both materials formed at the bottom of the weld nugget, and less migration occurred in the heat-affected zone of the AS at this time. The highest tensile strength can reach 194 MPa, accounting for 82.6% of the copper. The presence of brittle phases Cu5Zn8, AgZn3 and AgZn caused the hardness to fluctuate slightly.

Application of Convolutional Neural Network for Classification and Tracking of Weld Seam Shapes for TAL Brabo Manipulator

With ongoing advancements in robotics, robotic welding has gained popularity in industries since it reduces human intervention in hazardous and unpleasant working environment. Welding is a process in which two workpieces are joined together. The edge interface of the two halves are called weld seam. The main scope of this paper is online detection and classification of different shapes of weld seam from webcam using 2D Convolutional Neural Networks (CNN) in MATLAB. The problem with real time detection of weld seams accurately is that images contain high noise levels that are difficult to process leads to reduced tracking accuracy with traditional image processing techniques. To surpass this problem, this paper presents a low cost solution to detect and trace weld seam using CNN which has the powerful feature extraction capability and images are captured using webcam. This proposed methodology can be used to detect any weld seam shapes and classify automatically. To detect the weld seam, 1000 datasets of different weld shapes have been created with noise using 2D vision sensor and it is pre trained by 2D convolutional technique. Using this pretrained CNN model, live weld shape images are captured and classified according to the different shapes making the robot to track corresponding weld seam path. Experimental analysis is performed in 5 DOF TAL Brabo manipulator in which servomotors of the robotic arm are controlled by Trio motion controller which can communicate with MATLAB through ActiveX COM object. Experimental validation has been done based on probability scores and accuracy.

Laser welding with side-gas application and its impact on spatter formation and weld seam shape

Spattering is a quality issue within deep penetration laser welding processes resulting in time-consuming and cost-intensive post-processing. In this study, the formation of unconventional weld shapes, e.g. with bulge formation was observed in a lap-joint, while using a side-gas jet to enlargen the capillary opening. During quasi-stationary conditions, spattering could not be detected. It was found that in addition to a side-gas jet, the implementation of conventional center-gas is required. However, the type of shielding gas (N2, Ar, He) used for both, the center- as well as the side-gas does not impact on the formation of the characteristic bulge shape. Furthermore, bulge characteristics strongly depend on the welding speed. Therefore, the formation of latter is attributed to surface tension driven melt flows. In conclusion, spattering can be virtually non-existent if the capillary enlargement resulting from the side-gas jet is kept above a certain threshold.

Dynamic laser beam shaping for laser aluminium welding in e-mobility applications

High demanding novel laser welding applications are currently encountered in e-mobility sector such as overlap joint of thin aluminium alloys without full penetration for battery coolers and battery boxes. In this work, high dynamic laser profiles enabled by unique CIVAN proprietary Coherent Beam Combining (CBC) and Optical Phase Array (OPA) technologies are explored. Experimental investigation of overlap welding of 3003 aluminium alloy plates of 0.8mm thickness at speeds over 10m/min and the study of main process parameters, various beam shapes and oscillation patterns at high frequency up to MHz are undertaken. Effects of laser beam intensity profiles, oscillation frequencies in resulting seam shapes are presented. Process optimization is carried out in terms of weld seam geometry width and depth of penetration avoiding defects as porous, cracks and voids in the interface. Quality of weld joints is evaluated by cross sections macrographs and metallographic examination.

Seismic performance of precast joint in assembled monolithic station: effect of assembled seam shape and position

Precast concrete structure has many advantages, but the assembled seam will affect potentially the overall seismic performance of structure. Based on the sidewall joint located in the bottom of assembled monolithic subway station, the main objectives of this study are, on one hand to present an experimental campaign on the seismic behavior of precast sidewall joint (PWJ) and cast-in-place sidewall joint (CWJ) subjected to low-cycle repeated loading, and on the other hand to explore the effect of shape and position of assembled seam on load carrying capacity and crack width of precast sidewall joint. Two fullscale specimens were designed and tested. The important index of failure pattern, loading carrying capacity, deformation performance and crack width were evaluated and compared. Based on the test results, a series of different height and variablyshape of assembled seam of precast sidewall joint were considered. The test and numerical investigations indicate that, (1) the carrying capacity and deformation capacity of precast sidewall and cast-in-place sidewall were very similar, but the crack failure pattern, bending deformation and shearing deformation in the plastic hinge zone were different obviously; (2) the influence of the assembled seam should be considered when precast underground structures located in the aquifer water-bearing stratum; (3) the optimal assembled seam shape and position can be suggested for the design of precast underground concrete structures according to the analysis results.

Flexible shape of seam for image retargeting with face detection

Flexible shape of seam for image retargeting with face detection

Mechanical and microstructure analysis of AA6061 and Ti6Al4V fiber laser butt weld

Dissimilar metal welding involves the joining of two or more different pure metals or alloys, usually by melting and mixing and often with the addition of filler metal. There are several types of dissimilar metal welds including stainless steel, either as base metal or as filler metals. Dissimilar metal joints have distinctive features because of differences in the chemical composition of base metal and filler material. Their alloying elements will diffuse intensely during welding. The structures near the fusion line are very complex. Despite of great potentiality in aircraft and automotive industries, dissimilar joining of hybrid Al-Ti structures is often challenging because of the unavoidable formation of brittle intermetallic compounds, mixing of molten phases, and significant differences in material properties. In this work, dissimilar 2mm thickness AA6000 and Ti6Al4V butt joints were produced by shifting an Yb fiber laser beam on the upper surface of the Ti sheet. Neither filler wire nor groove preparation was adopted. Different working conditions and seam shapes were assessed. The welds were characterized in terms of metallurgical and mechanical behaviors.

Electromagnetic Shielding Material Effects on the Ordnance Store Protection

A kind of entity modeling and simulation method of the electromagnetic shielding research is put forward based on the FEKO software for ammunition warehouse wall with different properties and thickness of protective coatings. Simulation shows that it can significantly improve the high frequency electromagnetic field shielding effectiveness for adding the carbon powder, steel fiber and other conductive materials in the concrete, but not much effect on low frequency electromagnetic field. Metal coating with low electrical conductivity of the composite coating has higher shielding effectiveness with increase of the external electromagnetic field frequency and intensity, it has high shielding effectiveness for metal coating with low conductivity of the composite coating. The shielding effectiveness is gradually reduced for seam hole, but at 0.7 ~ 0.8 GHz resonance occurs, the shielding effectiveness of the worst, the shielding effectiveness on the Ordnance depot has a effect for reinforced steel bar mesh size and network mode, and the diameter of hole seam shape and size, it provides technical support and method for the ammunition electromagnetic protection etc.

Impact of Carbon Seam on Freeze Profile in Aluminum Reduction Cell

Thermal balance of an aluminium reduction cell is indicated by a stable freeze profile with acceptable thickness. One of the main factors which contributes to a stable freeze profile, where the freeze is not extending beyond the anode shadow is the cell lining design. In this study, a 3D quarter cell thermo-electric model of an 86 kA cell was developed using ANSYS. The model was validated with the plant measurements and subsequently utilized to evaluate the influence of carbon seam on the freeze profile in the aluminium reduction cell. The simulations were conducted both at design amperage and at increased amperage. It was observed that the impact of the seam shape was significant on the freeze profile and seam shape modifications could be investigated for achieving a stable freeze profile and for amperage increase programs. A nearly vertical seam provided a stable freeze profile both at design and higher amperages compared to conventional bevel shaped seam.

Study of Additional Compensation Shielding Gas Technique for Pulsed MIG Seam Welding

This paper proposes a novel additional compensation shielding gas technique for seam welding as a method to overcome weld defects caused by atmospheric exposure of high-temperature solid and liquid state welding seams. This technique can be used to appropriately modify the existing pulsed MIG welding system through the addition of a gas control branch channel, allowing for control of compensation shielding gas flow to the system. A plate overlay experiment was carried out with 18-8 austenitic stainless steel base metal and a modified pulsed MIG welder with a modified a gas control branch channel. The results suggest that this technique can be used to meliorate weld defects, improve welding seam shape and enhance welding efficiency.

Laser beam welding of electrical contacts of lithium-ion batteries for electric- and hybrid-electric vehicles

Lithium-ion batteries are preferred in electric and hybrid-electric vehicles due to their high energy density. In the course of developing high performance battery systems, which consist of over a hundred single cells, the energy efficiency still needs to be increased. One promising measure concerning this purpose is to reduce the electrical losses of contacts between the lithium-ion cells using laser beam welding. This joining technology offers the opportunity to vary the contact area as well as its geometry or position in the joining zone. Nevertheless, aging effects of the cells result in a mechanical stress at the joints between the terminal and the busbar. Varying the geometrical shape of the contact area opens a high potential to reduce these mechanical stresses of the contacts within a high voltage battery. This work presents a method to optimize the addressed geometrical shape of the weld seam in order to minimize the mechanical stresses of electrical contacts. A solution is proposed to calculate the optimum weld seam shape by the use of a genetic algorithm (GA) linked with a solid mechanics FEM simulation. The GA compiles alternative weld seam shapes, while the FEM simulations evaluate their mechanical properties. The optimised result is further verified within an experimental study.