A Review Paper On Vision Based Identification, Detection And Tracking Of Weld Seams Path In Welding Robot Environment

Welding is an important technology especially for joining between two metals, fabricated and repairing metals products in manufacturing industries such as in automotive industries. To increase the productivity and lower cost, today the welding operation in industries introduces the welding robot. The main challenges to using welding robot is time taken to program robot path for a new job in low to medium volume manufacturing industries. This paper begins with the review of identified, detected and tracked the weld seams path with different type of welding in welding environment. Next, a review of analysis an identified and detect the weld seams path approaches is included with advantages, drawback and limitation. This paper is concluded by a comprehensive summary which discussed the disadvantages and limitation of a robust approach in each stage. The improvement of a new approach in each stage depends on the lack, limitation and the results which are expected from the work

Entropy in Image Analysis II

Image analysis is a fundamental task for any application where extracting information from images is required. The analysis requires highly sophisticated numerical and analytical methods, particularly for those applications in medicine, security, and other fields where the results of the processing consist of data of vital importance. This fact is evident from all the articles composing the Special Issue "Entropy in Image Analysis II", in which the authors used widely tested methods to verify their results. In the process of reading the present volume, the reader will appreciate the richness of their methods and applications, in particular for medical imaging and image security, and a remarkable cross-fertilization among the proposed research areas

Creep monitoring using permanently installed potential drop sensors

Creep is the primary life limiting mechanism of static high temperature, high pressure power station components. Creep state evaluation is currently achieved by surface inspection of microstructure during infrequent outages; a methodology which is laborious, time consuming and considered inadequate. The objective of this work is to develop a monitoring technique that is capable of on-load creep damage monitoring. A continuous update of component integrity will enable better informed, targeted inspections and outage maintenance providing increased power generation availability. A low-frequency, permanently installed potential drop system has been previously developed and will be the focus of this thesis. The use of a quasi-DC inspection frequency suppresses the influence of the electromagnetic skin effect that would otherwise undermine the stability of the measurement in the ferromagnetic materials of interest; the use of even low frequency measurements allows phase sensitive detection and greatly enhanced noise performance. By permanently installing the electrodes to the surface of the component the resistance measurement is sensitive to strain. A resistance - strain inversion is derived and validated experimentally; the use of the potential drop sensor as a robust, high temperature strain gauge is therefore demonstrated. The strain rate of a component is known to be an expression of the creep state of the component. This concept was adopted to develop an interpretive framework for inferring the creep state of a component. It is possible to monitor the accumulation of creep damage through the symptomatic relative increase in strain rate. By taking the ratio of two orthogonal strain measurements, instability and drift common to both measurements can be effectively eliminated; an important attribute considering the necessity to monitor very low strain rates over decades in time in a harsh environment. A preliminary study of using the potential drop technique for monitoring creep damage at a weld has been conducted. Welds provide a site for preferential creep damage accumulation and therefore will frequently be the life limiting feature of power station components. The potential drop technique will be sensitive to both the localised strain that is understood to act as precursor to creep damage at a weld and also the initiation and growth of a crack. Through the course of this project, two site trials have been conducted in power stations. A measurement system and high temperature hardware that is suitable for the power station environment has been developed. The focus of this thesis is the effective transfer of the technique to industry; the realisation of this is detailed in the final chapter.Open Acces

Optical In-Process Measurement Systems

Information is key, which means that measurements are key. For this reason, this book provides unique insight into state-of-the-art research works regarding optical measurement systems. Optical systems are fast and precise, and the ongoing challenge is to enable optical principles for in-process measurements. Presented within this book is a selection of promising optical measurement approaches for real-world applications

NASA Tech Briefs, August 1994

Topics covered include: Computer Hardware; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences; Books and Reports

Forum Bildverarbeitung 2020

Image processing plays a key role for fast and contact-free data acquisition in many technical areas, e.g., in quality control or robotics. These conference proceedings of the “Forum Bildverarbeitung”, which took place on 26.-27.11.202 in Karlsruhe as a common event of the Karlsruhe Institute of Technology and the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation, contain the articles of the contributions

Disk laser welding of metal alloys for aerospace

2011 - 2012Laser welding is the logical processing solution to accomplish different needs. Improvements at the design stage are actually aimed to remove any mechanical fastening, thus moving towards a technology which would not increase the joint thickness; moreover, a number of benefits in comparison with conventional welding methods are provided when considering laser beams, since deep penetration is achieved and the energy is effectively used where needed, thus melting the interface to be joined rather than excessively heating up the base metal, which would suffer from thermal distortion and degradation of metallurgical properties otherwise. Further advantages are achieved in laser welding with thin disk sources, since high output power, high efficiency and good beam quality are simultaneously delivered, unlike traditional laser systems; costs are significantly reduced in comparison with lamp-pumped laser systems. As a consequence, specific interest is shown in aerospace where strict specifications apply. Nevertheless, a number of issues must be addressed, depending on the material to be welded, as many variables and sub processes concerning fusion and vaporization are involved in laser welding and a delicate balance between heating and cooling is in place within a spatially localized volume. Therefore, extensive studies are required to manage both the stability and the reproducibility of the overall process, before introducing any change in industrial environments. Methods, experimental results and discussions concerning laser welding of common metal alloys for aerospace are provided in this Ph.D. thesis. A general view of applications and basic advantages of laser welding is first given, with mention to diagnostics and safety. Hence, the principles of laser emission are examined, with respect to the architecture of the sources, beam geometry, quality and efficiency, in order to better portray the benefits of a thin disk laser concept. Processing dynamics of laser welding are explained afterward, referring to conduction and key-hole mode, instability, gas supply and leading governing parameters such as laser power, welding speed, defocusing and beam angle to be considered in the experimental work. Procedures are provided for proper bead characterization, from preliminary examinations including non destructive tests such as fluorescent penetrant inspections and radiographic tests, to sample preparation and eventual mechanical assessment in terms of tensile strength and Vickers micro hardness in the fused zone. A straightforward description of the design of experiment approach and the response surface methodology is given, so to introduce the testing method to be taken, as well as the steps for data elaboration via statistical tools. Hence, four case studies about metal aerospace alloys are presented and discussed in their common seam configuration: autogenous butt and overlapping welding of aluminum alloy 2024; autogenous butt welding of titanium alloy Ti-6Al-4V; dissimilar butt welding of Haynes 188 and Inconel 718; dissimilar overlapping welding of Hastelloy X and René 80. All of the welding tests were conducted at the Department of Industrial Engineering at the University of Salerno; a Trumpf Tru-Disk 2002 Yb:YAG disk-laser source with a BEO D70 focusing optics, moved by an ABB IRB 2004/16 robot was employed. When needed, additional tests for the purpose of specific bead characterization were conducted by Avio and Europea Microfusioni Aerospaziali. As general procedure for each topic, the operating ranges to be examined are found via preliminary trials in combination with the existing literature on the subject. Then, special consideration is given to the processing set-up, the resulting bead profile, possible imperfections, defects and overall features; consistent constraint criteria for optimization of the responses are chosen on a case-by-case basis depending on materials and seam geometry and referring to international standards as well as customer specifications for quality compliance. Optimal combinations of the input welding parameters for actual industrial applications are eventually suggested, based on statistical tools of analysis. Convincing reasons are provided to give grounds to improvements in real applications. Moreover, based on the results, a proper device for bead shielding, to be conveniently adjusted depending on both geometry and materials to be welded has been designed, produced and patented (SA2012A000016). As concerning aluminum welding, a comprehensive description is given for laserrelated issues: reflectivity and thermal conductivity influence on the material response is illustrated; the porosity evolution is discussed with respect to thermal input and defocusing; a theory for softening in the fused zone is provided through energy dispersive spectrometry and estimations of magnesium content in the crosssection. Optimization is performed for butt configuration of 1.25 mm thick sheets; the discussion about the interactions among the governing factors is deepen with reference to overlapping welding. With respect to titanium welding, optimization is performed for 3 mm thick butt welding; the resulting micro structure in the weld is discussed since it is thought to be closely related to the mechanical properties. In particular, special care is taken of the grain size as a function of the governing factors. Dissimilar welding of super alloys is considered for gas turbine components; for this specific purpose, laser welding is expected to offer a valid alternative to arc and electron beam welding, whose weaknesses are pointed out. Given their actual application in the engine, Haynes 188 and Inconel 718 are examined in butt welding configuration, whilst an overlapping geometry is preferred for Hastelloy X and René 80. Considerable tolerances are matched, thus promoting the suggested range of the operating variables. [edited by author]XI n.s

Interlaminar bonding in ultrasonic consolidation

Ultrasonic Consolidation (UC) is a solid state additive manufacturing process which fabricates three-dimensional objects by ultrasonically joining metal foils together, layer-bylayer, to form a solid part. A wide range of materials can be used to fabricate parts by UC and products with complex internal geometry can be generated by shaping the crosssection throughout the build using Computer Numerically Controlled (CNC) milling. As a result of its ability to embed various secondary materials and fibres in metal matrices, UC has emerged as a potential method of fabricating multi-functional materials and structures. [Continues.