Data Analysis and Modeling Techniques of Welding Processes: The State-of-the-Art

Information contributes to the improvement of decision-making, process improvement, error detection, and prevention. The new requirements of the coming Industry 4.0 will make these new information technologies help in the improvement and decision-making of industrial processes. In case of the welding processes, several techniques have been used. Welding processes can be analyzed as a stochastic system with several inputs and outputs. This allows a study with a data analysis perspective. Data mining processes, machine learning, deep learning, and reinforcement learning techniques have had good results in the analysis and control of systems as complex as the welding process. The increase of information acquisition and information quality by sensors developed at present, allows a large volume of data that benefits the analysis of these techniques. This research aims to make a bibliographic analysis of the techniques used in the welding area, the advantages that these new techniques can provide, and how some researchers are already using them. The chapter is organized according to some stages of the data mining process. This was defined with the objective of highlighting evolution and potential for each stage for welding processes

Machine Learning Based Defect Detection in Robotic Wire Arc Additive Manufacturing

In the last ten years, research interests in various aspects of the Wire Arc Additive Manufacturing (WAAM) processes have grown exponentially. More recently, efforts to integrate an automatic quality assurance system for the WAAM process are increasing. No reliable online monitoring system for the WAAM process is a key gap to be filled for the commercial application of the technology, as it will enable the components produced by the process to be qualified for the relevant standards and hence be fit for use in critical applications in the aerospace or naval sectors. However, most of the existing monitoring methods only detect or solve issues from a specific sensor, no monitoring system integrated with different sensors or data sources is developed in WAAM in the last three years. In addition, complex principles and calculations of conventional algorithms make it hard to be applied in the manufacturing of WAAM as the character of a long manufacturing cycle. Intelligent algorithms provide in-built advantages in processing and analysing data, especially for large datasets generated during the long manufacturing cycles. In this research, in order to establish an intelligent WAAM defect detection system, two intelligent WAAM defect detection modules are developed successfully. The first module takes welding arc current / voltage signals during the deposition process as inputs and uses algorithms such as support vector machine (SVM) and incremental SVM to identify disturbances and continuously learn new defects. The incremental learning module achieved more than a 90% f1-score on new defects. The second module takes CCD images as inputs and uses object detection algorithms to predict the unfused defect during the WAAM manufacturing process with above 72% mAP. This research paves the path for developing an intelligent WAAM online monitoring system in the future. Together with process modelling, simulation and feedback control, it reveals the future opportunity for a digital twin system

The application of high power lasers to the welding of tee section joints in ship production

PhD ThesisThe use of computers by naval architects has revolutionised ship design and -construction management. The use of high power laser technology could similarly revolutionise production processes to produce a quantum leap in productivity. Facilitating low heat input materials processing, the laser is suited to various cutting, welding and heat treatment applications in shipbuilding to increase productivity through improved product accuracy. From these processes, the Author has concentrated on the application of high power lasers to the welding of tee section joints - the most common joint configuration in ship structures - by a single sided method (skid welding) to give both the lowest possible heat input and greatest flexibility. -Using a lOkW laser, single pass fully penetrating skid welds may be produced for joints in plate of up to 15mm thick, but using this size of laser, production parameter envelopes to produce visually and structurally sound joints reduce in size as plate thickness increases to greater than 10mm. It is shown that fully penetrating laser skid welds produced in steel conventionally used for surface vessel construction are of superior structural quality to fillet welds as required by classification society rules. The work has shown that achieving process consistency in an automated production based skid welding workstation operating with existing levels of joint tolerance will be dependent not only on well designed laser and beam delivery harware but also on suitable on-line adaptive control systems. It has been demonstrated that by employing laser skid welding for steelwork fabrication, an increase in productivity can be gained, principally through increased processing speed and improved product accuracy.British Shipbuilders: The Science and Engineering Research Council

Technology for the Future: In-Space Technology Experiments Program, part 1

The purpose of the Office of Aeronautics and Space Technology (OAST) In-Space Technology Experiment Program (In-STEP) 1988 Workshop was to identify and prioritize technologies that are critical for future national space programs and require validation in the space environment, and review current NASA (In-Reach) and industry/university (Out-Reach) experiments. A prioritized list of the critical technology needs was developed for the following eight disciplines: structures; environmental effects; power systems and thermal management; fluid management and propulsion systems; automation and robotics; sensors and information systems; in-space systems; and humans in space. This is part one of two parts and is the executive summary and experiment description. The executive summary portion contains keynote addresses, strategic planning information, and the critical technology needs summaries for each theme. The experiment description portion contains brief overviews of the objectives, technology needs and backgrounds, descriptions, and development schedules for current industry, university, and NASA space flight technology experiments

Development of a real-time ultrasonic sensing system for automated and robotic welding

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The implementation of robotic technology into welding processes is made difficult by the inherent process variables of part location, fit up, orientation and repeatability. Considering these aspects, to ensure weld reproducibility consistency and quality, advanced adaptive control techniques are essential. These involve not only the development of adequate sensors for seam tracking and joint recognition but also developments of overall machines with a level of artificial intelligence sufficient for automated welding. The development of such a prototype system which utilizes a manipulator arm, ultrasonic sensors and a transistorised welding power source is outlined. This system incorporates three essential aspects. It locates and tracks the welding seam ensuring correct positioning of the welding head relatively to the joint preparation. Additionally, it monitors the joint profile of the molten weld pool and modifies the relevant heat input parameters ensuring consistent penetration, joint filling and acceptable weld bead shape. Finally, it makes use of both the above information to reconstruct three-dimensional images of the weld pool silhouettes providing in-process inspection capabilities of the welded joints. Welding process control strategies have been incorporated into the system based on quantitative relationships between input parameters and weld bead shape configuration allowing real-time decisions to be made during the process of welding, without the need for operation intervention.British Technology Group (BTG

Lightweight design of a suspension arm by friction stir welding

The research seeks initially to investigate why a greater shift to lightweight technologies for suspension design has not occurred already over the mass market vehicle sector. It outlines the 'knock-on' benefits of lightweight design and identifies roadblocks which hinder progress. Recent annual metrics of vehicle performance related to mass are investigated. Focusing on individual areas of the suspension, benchmarking identifies the best practice amongst current designs. Manufacturing and process engineering strategies are proposed to support the development of lightweight products with considerably improved environmental acceptability.MIG (Metal Inert Gas) welding, universally accepted as the default joining technology in this field, was found to be restrictive to progress due primarily to detrimental effects on metallurgical, dimensional and process variation on both steel and aluminium products. The latest construction materials were reviewed for suspension application, but the focus remained on proposing light weighting solutions for material generically available in economic volumes today, but with new joining technologies to overcome current restrictions in using less of these materials for each component. Following a full review of the joining technologies available for automotive suspension construction, friction stir welding (FSW) was proposed as an alternative joining technology, with FSW replacing MIG in conjunction with extruded aluminium materials. This removed the barriers incumbent in the use of MIG, which demands a more conservative, heavier design to ensure adequate service lifetime. Design concepts were engineered to take maximum advantage of the strategy of aluminium, extrusions, assembled with friction stir welding. Several viable designs were conceived, from which two were developed and compared. The optimum design was then carried forward into a manufacturing feasibility stage. The extrusions were developed for ease of manufacture, and friction stir welding trials progressed on coupons (plain plates) to ensure that the process was viable. Aluminium in the soft and hardened conditions in different thicknesses and joint configurations were successfully friction stir welded during the trial. Future work would develop the extruded aluminium arm further, into the prototype phase, with sample extrusions being manufactured, FSW welded and assembled. Prototypes would then be rig tested to ensure mechanical and durability performance prior to vehicle trials. There are also possibilities in developing high strength thin wall multi-phase steel solutions, utilising Friction Stir Spot Welding (FSSW). This welding technology enhances the selection of high strength steels, as minimal strength is sacrificed during the joining operation

Predicting weld distortion in the design of automotive components

This project was set up in order to investigate whether it may be valid to use a simplified approach to weld distortion prediction in order to make an assessment of the distortions occurring in a welded structure. Distortion may manifest as problems associated with production, which increase costs and reduce profit. In order to validate the proposed prediction approach an experiment was developed to gain detailed information about distortions occurring in a series of simple welded joints. The joints and the parameters used for the experiment were based on the processes and applications of the case study company. The experiment was set up with the aim of evaluating the general magnitude and directions of distortion in bead on plate and butt weld joints to develop a database of distortion. The method for inspection of the experimental samples was to scan the parts using a 3D laser scanner to collect a detailed resolution point cloud that could be analysed. From the experimental results a number of key factors relating to the welded joints were found relating to material thickness, weld speed and penetration for the four different modes of distortion occurring. The experimental results were compared with the published data and equations presented by other authors, and some general agreements found, however, some differences were evident. In order for a designer to adjust the shape and form of a components design to counteract the distortions to achieve a nominal tolerance, based on these results, it was necessary to develop some new models specific to the materials and process variables of the case study company. Using an approach based on DoE software techniques, response surfaces for the experimental results were generated. This allowed equations to be developed for each distortion mode, which a designer could use to make predictions in the design phase to reduce risk from distortion

NASA Tech Briefs, August 1991

Topics: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Improvements in quality through weld thermal cycle modelling

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN017044 / BLDSC - British Library Document Supply CentreGBUnited Kingdo