Investigation of Aluminum-Stainless Steel Dissimilar Weld Quality using Different Filler Metals

Aluminum-stainless steel dissimilar welding processes yield unwanted disadvantages in the weld joint due to the large difference between the aluminum-stainless steel sheets’ melting points and the nearly zero solid solubility between these two metals. Aluminum AA6061 and stainless steel SUS304 were lap-welded by using Metal Inert Gas (MIG) welding with aluminum filler ER5356 (Group 1) and stainless steel filler ER308LSi (Group 2). The effects of the welding voltage and type of filler metals used on the weld joints were studied. The welding voltage had a significant effect on the welding process, as higher voltage resulted in poorer appearance of the weld joint and led to defects for both groups, such as porosity and incomplete fusion. The microstructure for Group 1 joints shows enrichment of Si particles, which benefited the joint properties as it increased the strength of the metal. The stainless steel substrates that spread into the aluminum side are much greater in volume for Group 1 than for Group 2 joints. Meanwhile, the microstructure of Group 2 joints (using ER308LSi filler) consists of chromium carbide precipitation which yields a high hardness value, but a brittle structure. The hardness values of the welded seams in Group 1 and Group 2 range from 60 to 100 HV and 160 to 230 HV, respectively. The fracture in the tensile test yielded the highest tensile strength of 104.4 MPa with aluminum fillers. The tensile strength of Group 1 joints ranging from 47.8 to 104.4 MPa was collectively higher than Group 2 joints, between 20.24 to 61.76 MPa. Based on the investigation throughout this study, it can be concluded that the welding voltage of 18 V and aluminum filler ER5356 is the optimum filler in joining the dissimilar metals aluminum AA6061 and stainless steel SUS 304

Automated Kinesthetic Trainer enhances Kinesthetic Memory development

This research studied the usefulness and effectiveness of providing movement guidance and haptic feedback in enhancing kinesthetic memory development. Participants were trained to perform horizontal welding in two different settings: free-hand (traditional group) or under such guidance (machine group). Their welding performance, as well as kinesthetic memory were evaluated. As for kinesthetic memory, since it is related to movement and posture, three parameters were measured: moving speed, muscle activity, and elbow angle. Machine group significantly outperformed traditional group in performance, and also showed significant better control of moving speed than the traditional group. However, muscle activity pattern and elbow angle didn\u27t differ significantly between two groups

A study of students’ motivation in using the mobile arc welding learning app

Welding is an introductory core subject that is taught in every mechanical engineering programs at all polytechnics in Malaysia. Normally students will learn the theoretical concepts of welding in the class followed by instruction-based training in the workshop. However, students have difficulty to follow everything that has been taught in the class in a limited time. Welding is dangerous for beginners and the welding environments are harmful and injurious to the health. In this paper, we introduce Mobile Arc Welding Learning (MAWL) app, a new approach for learning arc welding that incorporates mobile technology and enhanced with augmented reality (AR). The aim of this app is to enhance the contents used in arc welding learning materials used in the conventional learning by visualizing the information through the use of text, images, videos and 3D models. The MAWL app covers topics related to safety in welding, components of welding and steps in welding. The students can use the app to learn about welding on their own anytime and anywhere. The potential of using the MAWL app for welding learning among the polytechnic students has been investigated, specifically focusing on ease of use, learn ability, satisfaction, usefulness, motivation and engagement. The results of the evaluation indicate that the users strongly agreed on ease of use, learn ability, satisfaction, usefulness and motivation, while they agreed on engagement. These prove that the MAWL app has the potential to contribute to students’ welding learning through interactive and accessible information that satisfies the

VR welding kit: welding training simulation in mobile virtual reality using multiple marker tracking method

Welding simulation design using virtual reality (VR) is a challenge, as numerous developments and research in the mechanical engineering fields are involved. One of the key challenges is the improvement of realism by considering a mixed system of real and virtual equipment. A conceptual design and research management framework is currently lacking which leveraging the combination of VR and marker tracking techniques. This study seeks to examine and evaluating the use of mobile VR in welding training and how multiple markers tracking methods can be incorporated to overcome the current problems in VR for welding training simulation. In this study, the VR Welding Kit application is created by utilizing the Vuforia tracking engine to provide an alternative interaction for mobile devices. The results of the experiment revealed a benchmark comparison with Oculus Quest, the high-end VR system, to investigate the efficiency of the proposed multiple marker interaction technique. Performance for both devices was recorded. The System Usability Scales (SUS) have also been used to obtain users' acceptance rates using these devices. The Simulator Sickness Questionnaire (SSQ) was used to assess the cybersickness of participants. The performance results show that mobile VR have a moderate gap completion time in seconds if compared to Oculus Quest. The SUS scored a satisfactory result which is 73.33. Besides, SSQ surveys result shows that most of the participant felt the simulation sickness was minimal

ARC Welding Education: Mobile ARC Welding Learning App to Improve Students’ Motivation

All Mechanical Engineering students studying in Malaysian polytechnics have to take welding as a core subject. They will learn the basic theory in the classroom and proceed with instruction-based training in the workshop. With limited learning time in the classroom, students find it difficult to follow and understand everything that has been taught. Furthermore, welding is dangerous for beginners and the environment is hazardous to health. If students are not well prepared before going to the workshop, this might jeopardize themselves as well as the welding equipment. To help students be better prepared, a supplementary learning method is needed and the Mobile Arc Welding app has been introduced to them. A study has been conducted to determine whether the app contributes to the students’ learning process. The study was carried out among 67 mechanical engineering students of a polytechnic. The analysis involved Pearson Correlation and Regression in determining the impact of engagement, ease of use, learnability, satisfaction and usefulness on students’ motivation through the use of a welding app. The findings show that there are empirically positive and substantial correlations between motivation and engagement, satisfaction, and usefulness. However, there was no evidence of a positive and significant relationship between ease of use and learnability and welding learning motivation

Study on welder training by means of haptic guidance and virtual reality for arc welding

Gaining and improving welding skill is important for welders. The advent of virtual reality (VR) technology provides a new kind of medium for skill training. In this paper, a haptic arc welding training method is proposed based on VR and haptic guidance. The training method is designed to emulate the presence of a human tutor which feedbacks forces to a welder to show the proper force/position relation within pre-defined trajectories for attaining hand-mind-eye coordination skills in a virtual environment. Three basic welding operation skills, namely maintaining the proper arc length, maintaining the proper electrode angle, and maintaining the proper traverse speed are selected for training. The Phantom haptic device is used as the haptic interface. The haptic guidance is realized with proportional-plus-derivative (PD) feedback control of the error between the current and ideal trajectory. The proposed method is cost-less, effective, and environment-friend for the training of both novice and skilled welders. ©2006 IEEE.link_to_subscribed_fulltex

Development and evaluation of mixed reality-enhanced robotic systems for intuitive tele-manipulation and telemanufacturing tasks in hazardous conditions

In recent years, with the rapid development of space exploration, deep-sea discovery, nuclear rehabilitation and management, and robotic-assisted medical devices, there is an urgent need for humans to interactively control robotic systems to perform increasingly precise remote operations. The value of medical telerobotic applications during the recent coronavirus pandemic has also been demonstrated and will grow in the future. This thesis investigates novel approaches to the development and evaluation of a mixed reality-enhanced telerobotic platform for intuitive remote teleoperation applications in dangerous and difficult working conditions, such as contaminated sites and undersea or extreme welding scenarios. This research aims to remove human workers from the harmful working environments by equipping complex robotic systems with human intelligence and command/control via intuitive and natural human-robot- interaction, including the implementation of MR techniques to improve the user's situational awareness, depth perception, and spatial cognition, which are fundamental to effective and efficient teleoperation. The proposed robotic mobile manipulation platform consists of a UR5 industrial manipulator, 3D-printed parallel gripper, and customized mobile base, which is envisaged to be controlled by non-skilled operators who are physically separated from the robot working space through an MR-based vision/motion mapping approach. The platform development process involved CAD/CAE/CAM and rapid prototyping techniques, such as 3D printing and laser cutting. Robot Operating System (ROS) and Unity 3D are employed in the developing process to enable the embedded system to intuitively control the robotic system and ensure the implementation of immersive and natural human-robot interactive teleoperation. This research presents an integrated motion/vision retargeting scheme based on a mixed reality subspace approach for intuitive and immersive telemanipulation. An imitation-based velocity- centric motion mapping is implemented via the MR subspace to accurately track operator hand movements for robot motion control, and enables spatial velocity-based control of the robot tool center point (TCP). The proposed system allows precise manipulation of end-effector position and orientation to readily adjust the corresponding velocity of maneuvering. A mixed reality-based multi-view merging framework for immersive and intuitive telemanipulation of a complex mobile manipulator with integrated 3D/2D vision is presented. The proposed 3D immersive telerobotic schemes provide the users with depth perception through the merging of multiple 3D/2D views of the remote environment via MR subspace. The mobile manipulator platform can be effectively controlled by non-skilled operators who are physically separated from the robot working space through a velocity-based imitative motion mapping approach. Finally, this thesis presents an integrated mixed reality and haptic feedback scheme for intuitive and immersive teleoperation of robotic welding systems. By incorporating MR technology, the user is fully immersed in a virtual operating space augmented by real-time visual feedback from the robot working space. The proposed mixed reality virtual fixture integration approach implements hybrid haptic constraints to guide the operator’s hand movements following the conical guidance to effectively align the welding torch for welding and constrain the welding operation within a collision-free area. Overall, this thesis presents a complete tele-robotic application space technology using mixed reality and immersive elements to effectively translate the operator into the robot’s space in an intuitive and natural manner. The results are thus a step forward in cost-effective and computationally effective human-robot interaction research and technologies. The system presented is readily extensible to a range of potential applications beyond the robotic tele- welding and tele-manipulation tasks used to demonstrate, optimise, and prove the concepts