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1 – 10 of over 5000Stephen Mulligan, Geoff Melton, Ari Lylynoja and Keith Herman
Development and demonstration of an autonomous, mobile welding robot capable of fabricating large‐scale customised structures.
Abstract
Purpose
Development and demonstration of an autonomous, mobile welding robot capable of fabricating large‐scale customised structures.
Design/methodology/approach
An autonomous welding robot has been developed under the EC Framework V Growth program. The system comprises a global vision system for part location and orientation, and a robot transport vehicle (RTV) which carries a 6‐axis robot, robot controller, welding equipment, and local sensors at the welding torch. The RTV path, robot arm motion and weld process programming are performed automatically using sensors and specially customised simulation software.
Findings
The technology developed within the project was demonstrated, in November 2004, to be capable of identifying and welding large scale customised structures as found in the earth moving equipment and bridge fabrication industries.
Research limitations/implications
The project demonstrated that current sensor technology is capable of being applied successfully to autonomous robots, but further developments in sensor technology are required to improve accuracy and joint access.
Practical implications
The NOMAD concept of autonomous mobile robots provides an alternative solution to welding mass customised structures.
Originality/value
This project demonstrated, for the first time, the capability of autonomous robots to weld large scale customised structures.
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Gunnar Bolmsjö, Magnus Olsson and Per Cederberg
The development of robotized welding is truly impressive and is today one of the major application areas for industrial robots. The first industrial robots were introduced in the…
Abstract
The development of robotized welding is truly impressive and is today one of the major application areas for industrial robots. The first industrial robots were introduced in the early 1960s for material transfer and machine tending. Not long after that, robots were used for spot welding and in the early 1970s for arc welding as well. During the years, significant developments have taken place both concerning the robot equipment and the welding equipment to meet the different challenges within the application area. This paper describes the development and progress of robotization in welding over the years and also some projections and trends for the near future.
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The world's most powerful electron‐beam welding facility was officially commissioned in September, providing 75 k\V of beam power in a vacuum chamber measuring 7 × 3.6 × 3.6m…
Abstract
The world's most powerful electron‐beam welding facility was officially commissioned in September, providing 75 k\V of beam power in a vacuum chamber measuring 7 × 3.6 × 3.6m. Single pass welds in steel up to 200m thick may be produced at high speed and prototype fabrications may be welded in the large chamber using numerically controlled manipulating equipment.
Taotao Jin, Xiuhui Cui, Chuanyue Qi and Xinyu Yang
This paper aims to develop a specific type of mobile nonrigid support friction stir welding (FSW) robot, which can adapt to aluminum alloy trucks for rapid online repair.
Abstract
Purpose
This paper aims to develop a specific type of mobile nonrigid support friction stir welding (FSW) robot, which can adapt to aluminum alloy trucks for rapid online repair.
Design/methodology/approach
The friction stir welding robot is designed to complete online repair according to the surface damage of large aluminum alloy trucks. A rotatable telescopic arm unit and a structure for a cutting board in the shape of a petal that was optimized by finite element analysis are designed to give enough top forging force for welding to address the issues of inadequate support and significant deformation in the repair process.
Findings
The experimental results indicate that the welding robot is capable of performing online surface repairs for large aluminum alloy trucks without rigid support on the backside, and the welding joint exhibits satisfactory performance.
Practical implications
Compared with other heavy-duty robotic arms and gantry-type friction stir welding robots, this robot can achieve online welding without disassembling the vehicle body, and it requires less axial force. This lays the foundation for the future promotion of lightweight equipment.
Originality/value
The designed friction stir welding robot is capable of performing online repairs without dismantling the aluminum alloy truck body, even in situations where sufficient upset force is unavailable. It ensures welding quality and exhibits high efficiency. This approach is considered novel in the field of lightweight online welding repairs, both domestically and internationally.
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In this report, accounts will be presented on the experience obtained from approximately 100 practical applications of industrial robots. The industrial robots used derive partly…
Abstract
In this report, accounts will be presented on the experience obtained from approximately 100 practical applications of industrial robots. The industrial robots used derive partly from the company's own production as well as from other domestic and foreign robot manufacturers.
Hongliang Yu, Zhen Peng, Zirui He and Chun Huang
The purpose of this paper is to establish a maturity evaluation model for the application of construction steel structure welding robotics suitable for the actual situation and…
Abstract
Purpose
The purpose of this paper is to establish a maturity evaluation model for the application of construction steel structure welding robotics suitable for the actual situation and specific characteristics of engineering projects in China and then to assess the maturity level of the technology in the application of domestic engineering projects more scientifically.
Design/methodology/approach
The research follows a qualitative and quantitative analysis method. In the first stage, the structure of the maturity model is constructed and the evaluation index system is designed by using the ideas of the capability maturity model and WSR methodology for reference. In the second stage, the design of the evaluation process and the selection of evaluation methods (analytic hierarchy process method, multi-level gray comprehensive evaluation method). In the third stage, the data are collected and organized (preparation of questionnaires, distribution of questionnaires, questionnaire collection). In the fourth stage, the established maturity evaluation model is used to analyze the data.
Findings
The evaluation model established by using multi-level gray theory can effectively transform various complex indicators into an intuitive maturity level or score status. The conclusion shows that the application maturity of building steel structure welding robot technology in this project is at the development level as a whole. The maturity levels of “WuLi – ShiLi – RenLi” are respectively: development level, development level, between starting level and development level. Comparison of maturity evaluation values of five important factors (from high to low): environmental factors, technical factors, management factors, benefit factors, personnel and group factors.
Originality/value
In this paper, based on the existing research related to construction steel structure welding robot technology, a quantitative and holistic evaluation of the application of construction steel structure welding robot technology in domestic engineering projects is conducted for the first time from a project perspective by designing a maturity evaluation index system and establishing a maturity evaluation model. This research will help the project team to evaluate the application level (maturity) of the welding robot in the actual project, identify the shortcomings and defects of the application of this technology, then improve the weak links pertinently, and finally realize the gradual improvement of the overall application level of welding robot technology for building steel structure.
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Na Lv, Jiyong Zhong, Jifeng Wang and Shanben Chen
Surface forming control of welding bead is the fundamental study in automated welding. Considering that the vision sensing system cannot extract the height information of weld…
Abstract
Purpose
Surface forming control of welding bead is the fundamental study in automated welding. Considering that the vision sensing system cannot extract the height information of weld pool in pulsed GTAW process, so this paper designed a set of automatic measurement and control technology to achieve real-time arc height control via audio sensing system. The paper aims to discuss these issues.
Design/methodology/approach
The experiment system is based on GTAW welding with acoustic sensor and signal conditioner. A combination denoising method was used to reduce the environmental noise and pulse interference noise. After extracting features of acoustic signal, the relationship between arc height and arc sound pressure was established by linear fitting. Then in order to improve the prediction accuracy of that model, the piecewise linear fitting method was proposed. Finally, arc height linear model of arc sound signal and arc height is divided into two parts and built in two different arc height conditions, which are arc height 3-4 and 4-5-6 mm.
Findings
The combination denoising method was proved to have great effect on reducing the environmental noise and pulse interference noise. The experimental results showed that the prediction accuracy of linear model was not stable in different arc height changing state, like 3-4 and 4-5-6 mm. The maximum error was 0.635588 mm. And the average error of linear model was about 0.580487 mm, and the arc sound signal was accurately enough to meet the requirement for real-time control of arc height in pulse GTAW.
Originality/value
This paper tries to make a foundation work to achieve controlling of depth of welding pool through arc sound signal, then the welding quality control. So a new idea of arc height control based on automatic measuring and processing system through arc sound signal was proposed. A new way to remove environmental noise and pulse interference noise was proposed. The results of this thesis had proved that arc sound signal was an effective features and precisely enough for online arc height monitoring during pulsed GTAW.
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S.N. Santillan, S.B. Valdez, W.M. Schorr, R.A. Martinez and S.J. Colton
The purpose of this paper is to investigate the corrosion of the heat‐affected zone (HAZ) and weld zone of austenitic stainless steels that have been welded using two different…
Abstract
Purpose
The purpose of this paper is to investigate the corrosion of the heat‐affected zone (HAZ) and weld zone of austenitic stainless steels that have been welded using two different processes. The corrosion behavior is evaluated in synthetic seawater using the electrochemical polarization technique.
Design/methodology/approach
Welded and unwelded UNS S30403 specimens were welded by flux core arc, and gas tungsten arc welding (GTAW) techniques. The test equipment consisted of an electrochemical three‐electrode cell using synthetic seawater as the corrosive medium. The scan rate was 10 mV/s and the potential range was −500‐500 mV vs saturated calomel electrode. The pH for the synthetic seawater was around seven. The electrochemical tests were performed after 1, 2, 3, and, 11 weeks. The metal surface was characterized by examination using an inverted microscope and scanning electron microscopy.
Findings
The polarization measurements of the flux core arc welding‐HAZ showed a high corrosion susceptibility, while GTAW‐HAZ presented good corrosion performance.
Practical implications
With the application and correct interpretation of this electrochemical technique, designers, welding engineers, and manufactures can access important information and take correct decisions regarding welding processes to meet corrosion resistance requirements.
Originality/value
The methodology and approach of interpreting the polarization plots used in this research can be applied to study other welding techniques and different welded metals in specific corrosive media, which will be of value to the welding industry.
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Automatic arc‐welding machines have been used in manufacturing plant for a number of years now. They are special machines for a special purpose. But one of the main problems for…
Abstract
Automatic arc‐welding machines have been used in manufacturing plant for a number of years now. They are special machines for a special purpose. But one of the main problems for automatic arc‐welding machines is presented by assembly element inaccuracies. These inaccuracies arise even when the parts are being stamped in the press. What is no problem for the manual welder, for he sees the discrepancies and is able to bridge the gap, may only be solved by automatic arc‐welding machines if powerful clamping tools are used. The same problem is also present in principle when programmable inddustrial robots are used for arc welding instead of conventional automatic machines. However, initial successes have been recorded in bridging assembly element inaccuracies with an automatic program shift and pendulum movements for the welding torch attached to the industrial robot. In recent times, these features have been supplemented by the welding power source being equipped with a parameter selection unit.
M. Rogante, V.T. Lebedev, S. Kralj, L. Rosta and Törö
This paper addresses important technical problems related with methodological limitations of welding project methods currently adopted, mostly regarding numerical modelling…
Abstract
This paper addresses important technical problems related with methodological limitations of welding project methods currently adopted, mostly regarding numerical modelling procedure of welding processes. The progress in high nano‐technologies give rise to the same approaches to be applied in traditional mechanics and material science, really concerning welding processes using various methods and techniques. Recent investigations of welded joints have shown the benefits related to the employment of neutron techniques, to obtain substantial information advancing quality and durability that cannot be found by using other means. Small Angle Neutron Scattering (SANS) and Neutron Diffraction (ND), in particular, consent materials characterization at atomic and nanoscale level, offering to the existing technologies the essential contribution of precise structural methods. The basic theoretical aspects are described, and some SANS investigations of weldments are reported. An experimental programme has been recently projected to develop welding processes, with quality assurance improvement, safety enhancement, life‐time management and cost effectiveness of the considered joints.
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