Precision Welding Research Articles

Welded Gold Nanoparticle Assemblies Defined Plasmonic Coupling.

Nanoparticle assemblies with interparticle ohmic contacts are crucial for nanodevice fabrication. Despite tremendous progress in DNA-programmable nanoparticle assemblies, seamlessly welding discrete components into welded continuous three-dimensional (3D) configurations remains challenging. Here, we introduce a single-stranded DNA-encoded strategy to customize welded metal nanostructures with tunable morphologies and plasmonic properties. We demonstrate the precise welding of gold nanoparticle assemblies into continuous metal nanostructures with interparticle ohmic contacts through chemical welding in solution. We find that the welded gold nanoparticle assemblies show a consistent morphology with welded efficiency over 90%, such as the rod-like, triangular, and tetrahedral metal nanostructures. Next, we show the versatility of this strategy by welding gold nanoparticle assemblies of varied sizes and shapes. Furthermore, the experiment and simulation show that the welded gold nanoparticle assemblies exhibit defined plasmonic coupling. This single-stranded DNA encoded welding system may provide a new route for accurately building functional plasmonic nanomaterials and devices.

All-fiber 3 kW LP02 laser output based on long-period fiber grating for precise welding

An innovative all-fiber mode converter specifically designed for high-power fiber lasers is introduced. The mode converter relies on the coupling theory of long-period fiber gratings (LPFGs) and involves the fabrication of a LPFG, where the performance is meticulously studied by examining various fabrication parameters. The LPFG is integrated into a high-power fiber laser system to achieve efficient conversion from the LP01 mode to the LP02 mode with a conversion ratio of 90 % and a low transmission loss of only 0.088 dB. Under a 3.03 kW laser output, the LP02 fiber laser exhibits a remarkable laser-to-raman peak intensity ratio, which is 15.98 dB higher than that of the signal-mode fiber laser. Furthermore, during the welding process of a thick aluminum plate, the LP02 fiber laser demonstrates a significant increase of 1.2 times in the depth of the weld pool morphology compared to the signal-mode fiber laser, particularly evident when operating at a laser welding head speed of 100 mm/s. The mode converter with LPFG exhibits lower insertion loss, enhanced power-handling capacity, making it ideal for diverse high-power fiber laser applications with promising practical prospects.

High-power polarization-maintaining LP11-mode fiber laser based on long-period fiber grating for precise welding.

An LP11-mode output all-fiber laser was presented, utilizing long-period fiber gratings (LPFGs) and polarization-maintaining optical fiber (PMF). The LPFG was designed and fabricated, achieving a 90.56% efficiency in LP01 to LP11 mode conversion. Furthermore, the transmission stability of LP11-mode in the PMF was also explored, with the spatial mode overlap ratio exceeding 0.95. Ultimately, the high-power polarization-maintaining (PM) fiber laser, capable of the LP11 mode output, was constructed, with the output power of 600 W and the beam quality M2 of 2.84. During the process of welding a thick Al-plate, the LP11 fiber laser exhibits a notable 1.88 times greater depth of fusion compared to the commercial single-mode fiber laser, when operating at the laser welding head speed of 100 mm/s. For applications demanding non-circular symmetric high-order modes, this research holds substantial potential for widespread adoption within the field of industrial processing.

Analysis of Electric Current on Aluminum Plate Welding Using MMA (Manual Metal Arc) Method

Many industries depend on welding, which joins materials with heat. This research focuses on Manual Metal Arc (MMA) welding aluminum plates due to its adaptability for thin materials and compatibility with aluminum's unique properties. The study investigates how electric current affects aluminum plate MMA welding, improving welding methods. The study examined the effect of electric current on aluminum plates using the MMA method using a qualitative descriptive research design. Sorong Merchant Marine Polytechnic's workshop laboratory conducted the research from February to May 2023 using AWS E 6013 welding electrodes and ASTM A36 plates. Data was collected through observation, documentation, and literature review, then analyzed using data reduction principles. Results show that electric current variation significantly affects welding characteristics. Increased amperage penetrates deeper, but excessive current can melt and weaken joints. Amperage, weld rate, joint quality, and penetration depth must be balanced. The study emphasizes precise welding control, improving welding efficacy. The complex relationship between critical parameters emphasizes the need for careful equilibrium and the importance of following welding guidelines and parameters in the Welding Procedure Specification. As inadequate or excessive current can affect weld quality, this research improves MMA aluminum plate welding results.

Optimization of TIG welding process parameters on 304 austenitic stainless steel sheet metal using fuzzy logic based Taguchi method

TIG welding can be used to produce excellent weld quality and precise welding operation for sheet metals. The aim of this study was to get the best welding parameters for enhancing ultimate tensile strength, bending strength and Rockwell hardness of the butt-weld joint. The experimental work was used, and the experiment was carried out on 2 mm thickness of 304 austenitic-stainless steel sheet metal using the L9 orthogonal array of the Taguchi design. Automated TIG welding fixture was developed to control the welding speed accurately. The selected welding parameters were welding speed, current, voltage and gas flow rate with their three levels. Based on the fuzzy logic based Taguchi method, the best optimal levels of parameters were found at the values of 110 A of current, 13.86 cm/min of speed, 17.5 V of voltage and 7.5 L/min of gas flow rate. The analysis results of ANOVA showed that gas flow rate and current were found as the significant factors, and the contributions of the gas flow rate, current, speed and error were 47.63%, 34.34%, 16.49% and 1.54%, respectively. According to the confirmation tests, the multi response performance index mean value of the confirmatory test of 0.6068 was found between the 95% confidence interval of 0.5028 and 0.7314, and the maximum ultimate tensile strength, bending strength and Rockwell hardness were obtained 614.8 MPa, 765.32 MPa and 95.3 HRB, respectively.

Heat management and tensile strength of 3 mm mixed and matched connections of butt joints of S355J2+N, S460MC and S700MC

AbstractHigh‐strength structural steels are beneficial in terms of the sustainability of constructions due to the possible reduction of weight and overall material needs. Nevertheless, high‐strength steels have a smaller processing parameter range in regarding the specific heat input and resulting cooling rate. Especially the cooling time t8/5 characterizing the time span to cool down from 800 to 500 °C is an important indicator. Single layer butt‐welded gas metal arc welding (GMAW) connections of 3 mm plates between normal strength (S355J2+N, S460MC) and high‐strength steels (S700MC) as well as matched connections (S460MC, S700MC) are carried out. Hereby, the influence of the energy input, melting rate, joint preparation, filler metal (matching and undermatching) and backing methods are observed. Spatially resolved IR‐thermal observation shows variations within the welds of up to 50 % in the cooling time t8/5 depending on those parameters. These fluctuations lead to significant changes of the microstructure within the melting and heat‐affected zone. UCI hardness mappings show the softening and microstructural change within these zones. Those soft zones can be the region of failure for butt welded connections as shown by transverse tensile tests with spatially resolved optical strain measurements. The results obtained can be used to define more precise welding procedures of these types of connections and also are used to develop design rules for mixed connections made of normal strength and high‐strength steel.

An Efficient Method for Laser Welding Depth Determination Using Optical Coherence Tomography.

Online monitoring of laser welding depth is increasingly important, with the growing demand for the precise welding depth in the field of power battery manufacturing for new energy vehicles. The indirect methods of welding depth measurement based on optical radiation, visual image and acoustic signals in the process zone have low accuracy in the continuous monitoring. Optical coherence tomography (OCT) provides a direct welding depth measurement during laser welding and shows high achievable accuracy in continuous monitoring. Statistical evaluation approach accurately extracts the welding depth from OCT data but suffers from complexity in noise removal. In this paper, an efficient method coupled DBSCAN (Density-Based Spatial Clustering of Application with Noise) and percentile filter for laser welding depth determination was proposed. The noise of the OCT data were viewed as outliers and detected by DBSCAN. After eliminating the noise, the percentile filter was used to extract the welding depth. By comparing the welding depth determined by this approach and the actual weld depth of longitudinal cross section, an average error of less than 5% was obtained. The precise laser welding depth can be efficiently achieved by the method.

Chemically Welding Silver Nanowires toward Transferable and Flexible Transparent Electrodes in Heaters and Double-Sided Perovskite Solar Cells

Silver nanowires (AgNWs) are important materials for flexible transparent electrodes (FTEs). However, the loose stacking of nanowire junctions greatly affects the electric conductivity across adjacent nanowires. Soldering can effectively reduce the wire-wire contact resistance of AgNWs by epitaxially depositing nanosolders at the junctions, but the process normally needs to be performed with high energy consumption. In this work, we proposed a simple room-temperature method to achieve precise welding of junctions by adjusting the wettability of the soldered precursor solution on the surfaces of AgNWs. The nanoscale welding at nanowire cross junctions forms efficient conductive networks. Furthermore, reduced graphene oxide (rGO) was used to improve the stability of FTEs by wrapping the rGO around the AgNW surface. The obtained FTE shows a figure-of-merit (FoM) of up to 439.3 (6.5 Ω/sq at a transmittance of 88%) and has significant bending stability and environmental and acidic stability. A flexible transparent heater was successfully constructed, which could reach up to 160 °C within a short response time (43 s) and exhibit excellent switching stability. When laminating this FTE onto half perovskite solar cells as the top electrodes, the obtained double-side devices achieved power conversion efficiencies as high as 16.15% and 13.91% from each side, pointing out a convenient method for fabricating double-sided photovoltaic devices.

Study of Heat Source Model and Residual Stress Caused by Welding in GMAW of Al Alloy

An important trend in recent ships and offshore structures is that they require high strength as well as light weight. Due to this trend, various materials are being used to replace existing carbon steel, with aluminum alloys being used frequently. In particular, this trend is conspicuous in outfitting rather than in traditional structural strength members. As a typical example, the use of aluminum alloys is increasing in helideck structures and handrails, which are tertiary components. In order to make the example structures above, welding is absolutely necessary. There are various welding methods used for aluminum alloy, with gas metal arc welding (GMAW) the most widely used. It is very important to be able to simulate welding and to predict various physical quantities of this welding technique in the production of aluminum alloy structures. In particular, welding-induced residual stresses are always generated in a structure that has been welded, and can greatly influence structural stability. Therefore, this paper proposes a method to simulate the welding phenomenon using a precise welding heat source for various aluminum alloys. Additionally, the validity of the proposed finite element (FE) analysis method is verified by measuring the residual stress of the representative aluminum alloy.

Comparative Analysis of GTAW, GMAW, and FCAW Welding Results on A36 Steel Against Tensile Test and Macrostructure

Offshore building construction is inseparable from the fabrication process. Fabrication process that has an important role in terms of engineering, material repair and welding process. In offshore building construction, a precise welding method is needed on A36, where A36 steel is one of the main materials in the fabrication process of offshore buildings. In this study a comparison of welding results of GTAW, GMAW, and FCAW on A36 steel against Tensile Test and Macrostructure Test. The results of this research show that the best tensile test results are the GTAW welding method with an average value of ultimate strength of 462,168 MPa. Macrostructure testing which has the widest HAZ width is the GTAW welding method of 18,71 mm.

Sustainable Analysis of Process Parameters During TIG Welding of Dissimilar Joining Between 304 Stainless Steel and AISI 1018 Mild Steel

The present work investigates TIG in terms of strength and energy consumption during joining of dissimilar metal plates between 304 Stainless Steel and AISI 1018 Mild Steel. TIG welding basically promotes a sustainable environment because it consumes less energy. Energy conservation means to reduce imbalance between demand and energy supply that is necessary to protect ecological resources and natural environment. TIG welding is a precision welding process which makes possible for joining of thinner and lighter materials. Joining of various dissimilar metals becomes great interest owing to the different challenges that are posed by deviation in the material composition as well as the characteristics of the joined metals. The main objective is to optimize energy consumption and tensile strength by taking effective process parameters that are Current, Travel Speed and Gas Flow Rate and also determination of main influential process parameters on energy consumption and tensile strength by using Taguchi method. Contour plot has also been shown in this present investigation.

Comparative Analysis of FCAW, and GMAW Welding With Heat Input Variations on A36 Steel Against Vickers Hardness Test and Macrostructure

In offshore building construction, a precise welding method is needed on A36 steel, where A36 steel is one of the main materials in the fabrication process of offshore buildings. In this study a comparison of the results of the welding GMAW and FCAW with variations of the heat input on the A36 steel to the Hardness test, and the macrostructure test and the selection of the most appropriate method based on the results of the mechanical test analysis. The heat input variations used are GMAW 1.50 kJ / mm and 2.03 kJ / mm while for FCAW 1.90 kJ / mm and 2.30 kJ / mm. The results of this study are the best hardness test results are the FCAW welding method with a heat input of 2.30 kJ / mm with an average ultimate strength of 149.06 HVN, in the macro test the results show that the greater the heat input, the wider the HAZ area, this is shown by welding FCAW heat input 2.30 kj / mm which has a HAZ width area of 20 mm.

Testing of Selected Accuracy Parameters for the Single Axis Positioner at the Automated Workplace

Abstract Although some authors realized various measurement techniques and relevant standards in the experimental verification, the existing contributions still did not mention more complex automated workplaces with industrial robotic arm participation. To solve this, we provide a different view of the interconnection between individual devices (positioner, robot, etc.) controlled by third-party methods (Siemens products). Also, to obtain the necessary effectiveness, we tested and verified selected accuracy parameters for the participating device component (positioner). The proposed work tries to fulfill expectations for a precise welding technology (to ensure simultaneous movements of both the industrial robotic arm and positioner) to achieve higher quality and productivity. However, the components are from different manufacturers.

Impact of the Welding Parameters on the Width of the Welding beat in TIG Carbon Steel Welding

Tungsten Inert Gas (TIG) welding is otherwise known as the Gas Tungsten Arc soldering (GTAW) process which when significant levels of weld quality or high precision welding are required, is known to represent an advanced arc welding process. However the impact of the welding factors on this form of welding is important for its welding produced in single-pass welding. In this investigation, the autogenous Tungsten Inert Gas (TIG) welding was performed on a carbon mild steel plate with four parametric welding variables. High and low values of material thickness, welding current, welding speed and filler rod diameter have been measured in order to have an impact on an observable parametric response i.e. welding distance. Geometry of the weld bead has been investigated. An expert statistical software design expert has created a mathematical model, The experimental design is central composite design (CCD) and the sold width is the response measured by the Surface Response Methodology (RSM). It has been shown that the maintenance of a suitable parametric welding factor for a carbon steel plate gives substantial values of welding width.

Design and experiment of low-frequency ultrasonic nozzle integrating air-assistant system and acoustic levitation mechanism

Ultrasonic atomization nozzles are generally divided into two categories: high frequency and low-frequency ultrasonic atomization nozzles. Compared with high-frequency ultrasonic atomization nozzles (working frequencies>1 MHz), low-frequency ultrasonic atomization nozzles are not sensitive to clarity, temperature and viscosity of the liquid. However, they can control atomization quantity precisely, but the sizes of droplets generated by them are relatively large. In aeroponics cultivation, and precision welding, in such both cases, precise spraying control and tiny droplet sizes are expected. Therefore, how to decrease droplet size using low-frequency ultrasonic atomization nozzles is a valuable issue. In this paper a 60 kHz low-frequency ultrasonic atomization nozzle integrating air-assistant system and acoustic levitation mechanism was proposed and designed. Furthermore, the design was verified by FEA (Finite Element Analyzes) and impedance analyzer PV70A, and the verified results indicated relative design error was 0.49%. Driving voltage, spout angle, air pressure and levitating ball were taken as influential factors in the experimental protocol to the character in spray properties of this designed nozzle. A laser particle size analyzer was used to measure droplet sizes. Experiment results indicated that: the diameters of droplets generated by this nozzle at driving voltage 46 V were smaller than those at 40 V driving voltage; Both the assistant air and levitation mechanism could effectively change the diameters and uniformity of droplets; The minimum values of D10, D50, and D90 (D10, D50 and D90 were mean diameters when cumulative percentages of the samples’ diameter were 10%, 50% and 90%, respectively) were 23.06 µm, 31.14 µm and 41.38 µm, respectively. However, all those minimum values were presented at the same run (spout angle 0°, air pressure 0.05 MPa, having levitated ball, driving voltage 46 V); Levitating ball above the atomization surface would make droplet sizes more uniform and tinier. More importantly, the famous Lang equation which assumes that droplet diameters just decided by the liquid surface tension, density and ultrasonic atomizer’s working frequency needed to be revised because experimental results indicated that changing vibration amplitudes of ultrasonic atomization surface might lead to the changing of the droplet diameters and those results were at odds with the Lang equation. Keywords: nozzle, ultrasonic atomization, droplet, sonic levitation, air-assistant DOI: 10.25165/j.ijabe.20201306.5419 Citation: Gao J M, Hussian Tunio M, Chen Y M, He R. Design and experiment of low-frequency ultrasonic nozzle integrating air-assistant system and acoustic levitation mechanism. Int J Agric & Biol Eng, 2020; 13(6): 25–33.

Control of electron beam wielding parameters based on the gap scanning system data during the welding process

Influence of the gap between the welded edges when sealing the case of electronic devices on the magnitude of the electron emission sensor signal in the process of electron beam welding (EBW) is studied. The impact of electron beam current variation at a constant value of the focusing system current on the penetration depth with the increasing gap between the welded edges is determined. The dependence of the length of the weld at different electron beam currents on samples with an increasing gap between the welded edges is studied. The possibility of controlling the process of electron beam welding by electronic emission from the weld pool is presented. A sensor for electronic emission registration is proposed, which includes an electron collector and an electron current data record system as a part of the EBW installation. The efficiency of the electronic emission sensor directly in the process of sealing under precision welding modes is shown.

The study of Industrial design: The transformation of welder based on Tandem double-wire MIG welding

With the advent of industry 4.0, the new demands of welding industry are to adopt advanced welding technology and to realize automation. As a typical representative of welding technology, Tandem double-wire Metal-Inert Gas (MIG) welding could be used in precision welding and high-quality welding occasion. It has some superiority in higher welding efficiency and achieves automatic control easily. The paper presents a possible solution with transforming the common MIG welding tractor into special welding machine based on Tandem double-wire MIG welding. On the basis of product design and improvement methods, this paper integrates systems science and ergonomics to deeply discuss the application of Tandem MIG welding. The aim of transformation design is available to enhance the welding quality as well as to lower the production cost. And the research has consulting value on the design improvement of welding equipment for the manufacturing industries.

Mechanical Behavior of ARC Welding using Different Flux Materials

To perform welding process on the material under varying conditions with different flux materials, different welding parameters and further subjecting the material to various suitable tests such as tensile test, hardness test, optical tests and study the characteristics of the material under testing. The tests conducted on the welded work piece it is proposed the suitable parameters under which welding of greater precision can be performed. it is also analyzed the working conditions under which the selected work piece material of stainless steel grade 304 would deviate from its desired characteristics. From the results of the tests it is able to determine the conditions that would reduce the characteristics of the welded work piece. Thus it can be further used for reference when the welding process is done on the same material of stainless steel of grade 304. The electrodes that were chosen for this project were selected by the criteria of widely used and chief material in the welding of various grades of stainless steel. The composition of the chemicals that constitute the electrodes were tribiologically analyzed and studied. The need for high precision welding in large scale as well as small scale industries is relatively high as the threshold for errors in such areas are greatly undesirable. The results of this study would greatly contribute to the reduction of errors and defects in the welding operation.

Parametric Study of MIG Welding on Mild Steel (IS-2062 GRADE 2)

Metal Inert Gas (MIG) welding is a widely employed arc welding process that uses a consumable metal electrode to produce the weld. MIG welding produces very good quality weld when compared to other welding technologies with precise welding and comparatively little heat affected zone. MIG welding has become a popular choice of welding processes when high quality, precision welding is required at a comparatively lower cost. MIG welding is dependent on various input parameters but in the present work input parameters selected were welding current and weld time because these are the two major parameters which affect the weld quality. MIG welding finds its greatest application in welding both ferrous and non-ferrous metals and thus the most widely used arc welding process. A Taguchi Method (2 factors 3 levels) Design of Experiment (DOE) has been applied in this context to examine different welding defects through various tests like Hardness, Ultrasonography, Dye Penetration Test and tensile testing to examine its effect in each case. Finally using the Taguchi results have been optimized and through experiments and testing the best alternative with minimum welding defects and maximum yield strength and hardness number is reported successfully in the present work.

Global and Cluster-wise Regression Models for Total Bead Area as Welding Quality

Abstract In recent years, the automated welding system is used in high volume production industries for efficient and precise welding works. It can be applied for not only a simple machine, but also production of a single part. Therefore, a new algorithm that estimates the optimal welding parameters on a given bead geometry and accomplishes the desired mechanical properties of the weldment in order to make the automatic GMA (Gas Metal Arc) welding process, desirable. The developed algorithm could use for a wide range of material thicknesses, and be applicable for all welding positions. In addition, the models must be available in the form of mathematical equations, which can program to the robot, and give a high degree of confidence in predicting the bead dimensions. In this study, two regression models employing global regression analysis and cluster-wise regression analysis are proposed to be applicable for prediction of optimal welding parameters on the total bead area. For development of the proposed regression models, an attempt has been employed for finding the optimal welding parameters. A full factorial design is adopted to investigate welding parameters effect on total bead area in lap-joint welding. as a function of key output parameters in the automated GMA welding process was utilized. Not only the fitting of these models were checked and compared by using a variance test (ANOVA), but also the prediction of total bead area using the developed regression models was carried out the basis of the additional experiments. The fitness and variance test of the regression model is performed by using experimental data and ANOVA. The prediction of total bead area was carried out via regression model. Experimental results showed that the fitting on the experimental data of the cluster-wise regression model with the RMS value of 0.0026 is better than the developed global regression model for determining total bead area.