Arc Control Research Articles

Optimization of GMAW Processes in Robotic Welding: A Case Study from Automotive Manufacturing

The optimization of Gas Metal Arc Welding (GMAW) processes in robotic welding has become crucial for enhancing efficiency and quality in automotive manufacturing. This paper explores the integration of advanced robotic welding technologies, focusing on the use of the KUKA KR8 L8 Arc HW robot in GMAW applications. By leveraging artificial intelligence and sensor integration, this study demonstrates significant improvements in welding precision and process stability. Key advancements include the use of geometric and process sensors for real-time adaptive control, and the implementation of Fronius CMT for superior arc control and penetration. Detailed case studies from automotive manufacturing illustrate the practical benefits of these technologies, showcasing enhanced productivity, reduced cycle times, and improved weld quality. The findings underscore the importance of continuous innovation and optimization in robotic welding processes to meet the evolving demands of the automotive industry.

Study on the influence of transverse magnetic field on the arc and reignition characteristics of HVDC relays

It is of great significance to clarify the influence of transverse magnetic field (TMF) on arc control in high-voltage direct current (HVDC) relays. In this paper, the influence of TMF in a wide range of 0–140 mT on the arc characteristics of HVDC relays is studied, the experimental observations of arc reignition are carried out and the effect of arc reignition on contact erosion, the criterion of arc reignition and the mechanism of TMF enhancement on arc reignition are further analyzed. The results show that the TMF enhancement is beneficial for shortening the arc voltage stagnation duration and accelerating the speed of arc elongation, arc dispersion and dispersed arc motion, thereby improving the arc extinguishing performance. However, higher TMF leads to more severe and earlier arc reignition, as also shown in the experimental observations. The arc reignition further causes a sudden drop in arc voltage, prolonged arc duration and uneven contact erosion. To evaluate the occurrence of arc reignition caused by TMF enhancement, a simplified breakdown criterion is proposed through the defined characteristic variable C¯(t) . Based on this, the mechanism by which the TMF enhancement more easily causes arc reignition is explained, that is the higher TMF leads to an earlier and faster increase in C¯(t) and slightly reduces the breakdown threshold C¯∗(t5,D) . Further, measures to suppress the arc reignition are proposed.

Influence of SF6/N2 Mixed Gas Pressure on the Arc Control Ability of the Main Electrode in the Trigger Gap

Abstract In the controllable self-recovery energy-absorbing apparatus of the Baihetan-Jiangsu Hybrid UHVDC Transmission Project, a 30%SF6/70%N2 mixed gas is employed as the insulating medium within the trigger gap switch. In order to mitigate surface erosion on the main electrode of the trigger gap switch, as well as the inner wall of the insulating sleeve, and to reduce the usage of SF6, an investigation into the arc control ability of the main electrode under different pressures of the mixed gas has been initiated. The motion characteristics of the arc within the gap have been simulated using a Magnetohydrodynamics (MHD) model, and the variation pattern of the main electrode’s arc control ability within the pressure range of 0.1MPa to 0.4MPa was obtained by analyzing the changes in the arc volume. The arc control ability of the main electrode is influenced by the differences in physical parameters of mixed gas at different pressures. Results indicate that the electrode’s arc control ability experiences an initial increase followed by a subsequent decrease with the rising pressure of 30%SF6/70%N2 mixed gas. Notably, within the pressure range of 0.1MPa to 0.4MPa, the main electrode exhibits the highest arc control ability when the pressure of the mixed gas is 0.3MPa.

A Laser-Induced TIG Arc Narrow-Gap Welding Technique for TC4 Titanium Alloy Thick Plates Based on the Spatial Position Control of Laser, Arc and Filler Wire

In this paper, a novel laser-induced TIG arc narrow-gap welding technology is proposed for thick plates of TC4 titanium alloy. The feasibility of achieving high-performance welding joints is investigated by adjusting the spatial deviation position of the laser, arc, and filler wire. The results exhibited remarkable capabilities. By augmenting the laser-arc malposition, a stable deflection of the arc can be achieved, resulting in enhanced heat input to the sidewall adjacent to the laser side and improved fusion capability. Moreover, an inclined weld can be obtained through increased malposition between the filler wire and arc, which helps to improve interlayer fusion and suppress porosity defects. This method, involving alternating bilateral offsets between passes, successfully achieved narrow-gap welding of 24 mm-thick TC4 titanium alloy with an average tensile strength of 880.68 MPa (equivalent to 95.05% of base material strength). Therefore, this technology exhibits promising potential as an automated welding technique for achieving high-quality narrow-gap welding in titanium alloys.

Exploring the Location of Corneal Pigmented Arc and Myopia Control Efficacy in Orthokeratology-Treated Children Using Pentacam Measurements.

To determine the location and intensity of the corneal pigmented arc in orthokeratology (ortho-k)-treated children and its relationship with annual axial length (AL) change using Pentacam. This retrospective cohort study enrolled children aged 9 to 15 years who had been followed up for at least one year after ortho-k treatment for myopia control. A Pentacam was used to determine the location and intensity of pigmented arc after lens wear. Annual AL changes were further used as the outcome measurement to determine their relationships with the location and intensity of pigmented arc using generalized estimating equations (GEE). In total, 62 eyes from 33 patients (mean age 10.9 years) were included in our final analysis. The mean follow-up time was 30.6 months. The mean annual AL changes were 0.10 mm. Age statistically correlated with annual AL change (GEE, P= 0.033). In addition, the annual AL change was negatively associated with the relative vertical distance of the lowest density of pigmented arc point based on the visual center, pupil center, and corneal thinnest point after adjustment with age ( P =0.005, P =0.004, and P< 0.001, respectively). Pentacam could be a useful tool for evaluating the location and intensity of the corneal pigmented arc. In addition, there was a negative correlation between the vertical distance of the pigmented arc and annual AL change. These findings may provide important information regarding myopia control, next-generation ortho-k design, and prescription.

The novel strategy of electrical arc furnace design and control approach for voltage flicker investigation

Voltage flickers and harmonics are power quality (PQ) problems in the electric system during a variation and arc furnace (AF) adaptability. AF creations must determine a harmonic and flicker. This article evaluates complex AF systems. This article presents a newly established time domain (TD) static become to on an AF's V-I attributes (VIA). Static arc configurations are useful for harmonic analyses, but dynamic methods are needed for PQ studies, especially voltage flicker analysis. The MATLAB-based dynamic AF configuration is simulated for four different configurations. A response with configurations 1 and 4 varies from the real AF outcomes. The simulation results and numerical finding shows that configurations 2 and 3 are much more appropriate and produce better results for minimum 3rd harmonics for arc current, arc voltage, and point of common coupling (PCC) voltage. The novelty of this configuration is that the energy transferred to the load by the AF during the cycle of operation has been identified, making the developed scheme more reliable and dependent on the load's operational conditions. After that, effective applications of these configurations and other configurations' accuracy should be clarified.

Study of arc behavior and machining effects of the novel magnetic field assisted blasting erosion arc machining method

Electrical Arc Machining (EAM) is a high-efficiency, cost-effective method for machining electrical conductive materials especially difficult-to-cut ones. Because this thermal process relies on high-density energy to melt and remove material, effective arc control is crucial to maintain stable machining without overheating the workpiece. However, due to the limited discharge gap, it is difficult for the existing arc breaking methods to manage the arc plasma in a timely and uniform manner. This paper proposes a novel method named Magnetic Field Assisted Blasting Erosion Arc Machining (M-BEAM). This method introduces a magnetic field to enhance the control effect on arc plasma by directly influencing charged particles. Initially, the arc control and material removal mechanisms were revealed through an analysis and experiments of single arc discharge. Both simulated particle trajectory and high-speed photographs demonstrated that the arc plasma deflects much earlier in the magnetic field than that of traditional BEAM. Moreover, the expulsion effect of molten metal was significantly improved, resulting in a larger volume crater. Building on this, the magnetic-assisted arc control mechanism was utilized to enhance the performance of BEAM. Experimental results indicate that compared with traditional BEAM, Magnetic Field assisted BEAM increases its Material Removal Rate (MRR) by 10.09% while significantly reducing the Tool Wear Ratio (TWR) by 29.02%. Additionally, surface roughness (Sa) is decreased by 47.73%, and the thickness of the recast layer is decreased by 78.54%. Therefore, M-BEAM can further improve the machining performance and build a good foundation for subsequent machining.

Experimental investigation on the characteristic and voltage of low-current vacuum arc in vacuum OLTC

Due to vacuum interrupter's excellent interruption performance, an increasing number of on-load tap-changers (OLTCs) have chosen it as a load changeover switch in recent years. The stability of the arcing process is crucial for the interruption since the vacuum interrupter in OLTC must break current frequently with the requirement of long electrical life. In this paper, experiments on butt contacts and axial magnetic field (AMF) contacts applied in OLTC were carried out in a demountable vacuum chamber, and the arcing process was investigated by a high-speed camera. Investigations were conducted on the effects of opening speed, opening phase, current amplitude, and AMF on arc characteristics, e.g., arc expansion and arc voltage. The experiment findings demonstrated that expansion and instability of arc increased with higher opening speed, number of cathode spots moving to the inclined surface decreased with shorter arcing time, and that cathode spots' propensity to form group cathode spots increased with higher current. AMF lessened the impact of high opening speed and high current on the arcing process. The investigation carried out in this paper helps to better understand the characteristics of arc evolution and the influence of some key factors, which may serve as a guide for improving the design and vacuum arc control of vacuum OLTCs.

The first investigation of spot-scanning proton arc (SPArc) delivery time and accuracy with different delivery tolerance window settings

Objective. To investigate the impact of various delivery tolerance window settings on the treatment delivery time and dosimetric accuracy of spot-scanning proton arc (SPArc) therapy. Approach. SPArc plans were generated for three representative disease sites (brain, lung, and liver cancer) with an angle sampling frequency of 2.5°. An in-house dynamic arc controller was used to simulate the arc treatment delivery with various tolerance windows (±0.25, ±0.5, ±1, and ±1.25°). The controller generates virtual logfiles during the arc delivery simulation, such as gantry speed, acceleration and deceleration, spot position, and delivery sequence, similar to machine logfiles. The virtual logfile was then imported to the treatment planning system to reconstruct the delivered dose distribution and compare it to the initial SPArc nominal plan. A three-dimensional gamma index was used to quantitatively assess delivery accuracy. Total treatment delivery time and relative lost time (dynamic arc delivery time—fix beam delivery time)/fix beam delivery time) were reported. Main Results. The 3D gamma passing rate (GPR) was greater than 99% for all cases when using 3%/3 mm and 2%/2 mm criteria and the GPR (1%/1 mm criteria) degraded as the tolerance window opens. The total delivery time for dynamic arc delivery increased with the decreasing delivery tolerance window length. The average delivery time and the relative lost time (%) were 630 ± 212 s (253% ± 68%), 322 ± 101 s (81% ± 31%), 225 ± 60 s (27% ± 16%), 196 ± 41 s (11% ± 6%), 187 ± 29 s (6% ± 1%) for tolerance windows ±0.25, ±0.5, ±1, and ±1.25° respectively. Significance. The study quantitatively analyzed the dynamic SPArc delivery time and accuracy with different delivery tolerance window settings, which offer a critical reference in the future SPArc plan optimization and delivery controller design.

A time domain approach for the optimal control of wave energy converter arrays

Wave energy converters typically use various control methods to extract energy from ocean waves. The objective of the control system is to optimize the energy extraction process, taking into account the dynamics of the system and the wave conditions. The task of deriving the optimal control laws of wave energy converter arrays for regular and irregular waves using the Pontryagin minimum principle was previously investigated in the literature. The result is a combination between the singular arc and bang-bang control laws. For irregular waves, some complexity arises due to the radiation state-space representation, which requires ignoring the hydrodynamic coupling terms related to the added mass and radiation-damping coefficients; this reduces the computational complexity of the control force but adversely affects the solution's accuracy. Also, the derived control laws are specific to a particular wave condition. Recently, the optimal control of a flexible buoy wave energy converter was derived using the convolution representation for the radiation force. In this work, the optimal control laws of flexible buoy wave energy converters are modified to simulate wave energy converter arrays; then, the results are compared to those obtained by dropping the hydrodynamic radiation coupling terms. Although using a convolution representation adds computational complexity to the optimal control problem, it generates an equation that is generic to any wave condition, can be used with any wave spectrum, and provides an expression for the switching condition.

Model-Based Decision Support System for Electric Arc Furnace (EAF) Online Monitoring and Control

In this work, a practical approach for a decision support system for the electric arc furnace (EAF) is presented, with real-time heat state monitoring and control set-point optimization, which has been developed within the EU-funded project REVaMP and applied at the EAF of Sidenor in Basauri, Spain. The system consists of a dynamic process model based on energy and mass balances, including thermodynamic calculations for the most important metallurgical reactions, with particular focus on the modelling of the dephosphorisation reaction, as this is a critical parameter for production of high-quality steel grades along the EAF process route. A statistical scrap characterization tool is used to estimate the scrap properties, which are critical for reliable process performance and accurate online process control. The underlying process models and control functions were validated on the basis of historical production and measurement data of a large number of heats produced at the Sidenor plant. The online implementation of the model facilitates the accurate monitoring of the process behaviour and can be applied for exact process end-point control regarding melt temperature as well as oxygen, carbon and phosphorus content. Embedded within a model predictive control concept, the model can provide useful advice to the operator to adjust the relevant set-points for energy and resource-efficient process control.

Diagnostics of the drive of the control and protection system of the reactor plant ark type

The drive of the reactor control and protection system (CPS) is a system of normal operation, important for safety. Malfunctions of the drives of the ARC type CPS are often the initial events for accidents leading to unauthorized downtime. The currently existing standard methods for monitoring the parameters of the CPS do not allow for a reliable assessment of the condition of the drives. In this paper, it is proposed to implement an approach that provides an increase in sensitivity when recognizing the states of the drives of the ARC control system by processing the initial signals, which are vibroacoustic signals registered on the lid of the upper unit of the VVER reactor. A procedure for processing diagnostic signals using singular spectrum analysis is proposed. The proposed approach differs from the known ones by the presence of a scaling procedure, which is implemented by multiplying the eigenvalue matrices by the gankelized matrices of the source data. Due to scaling, the necessary sensitivity increase is provided. The expected increase in sensitivity is based on the fact that the eigenvalues reflect the structure of the signals, which changes significantly under the influence of the defect. The proposed method was used to process vibroacoustic signals registered on the lid of the upper block of the VVER reactor unit. Experimental studies were carried out at the test stand of Izhorskiye Zavody OJSC. The results of processing experimental data indicate a high quality of diagnosis. The hypothesis was clearly confirmed that the difference in the structure of diagnostic signals of serviceable and faulty equipment can manifest itself in the eigenvalues of the gankel signal matrices. The approach proposed in the article to the processing of diagnostic signals is easily amenable to automation and can be implemented in the development of a diagnostic system for the drive of an ARC-type CPS.

Parameter Optimization of Gas Metal Arc Welding Process for Welding Dissimilar Steels

Welding is a method of joining similar and dissimilar metals through the use of coalescence. GMAW is a semi-mechanized, fully-mechanized, or automatic process that is widely used in fabrication. GMAW is expected to evolve further to allow for better arc control, bead contour control, deposition control, and higher productivity. The goal of this study is to enhance welding process variables for dissimilar steel metal joints made of duplex stainless steel (DSS) to ASTM/UNS S32205 and erosional steel CORTEN-A to ASTM A242. Such a dissimilar metal joint finds use in the transportation sector, particularly in the construction of rail cars. The square butt joint between two 2 mm-thick sheets was investigated using the gas metal arc welding (GMAW) process with CO₂ as the shielding gas and flux-cored wire of grade 309L as the filler material. The L₉ Taguchi array was used to optimize the tensile strength of the resulting weld joint, which was the desired quality characteristic. GMAW process parameters such as voltage, wire feed rate, and welding speed are optimized at three levels. Using ANOVA, the effects of each factor have been studied. It was found that the ideal set of parameters exists and that the voltage is the most crucial factor. A confirmation test was performed to validate the results, and it was accompanied by a figure and tables.

(Invited) Advances in Synthesis of Nanomaterials By Atmospheric Arc Discharge with Pulsed Power

Plasmas are common tools used for synthesis and modification of nanoparticles. All techniques aim at providing high quality, nanostructured materials with well-defined crystalline state and functional properties. The most consolidated cold plasma nanosynthesis methods are pulsed-DC physical/chemical vapour deposition (PVD/CVD), high power impulse magnetron sputtering (HiPIMS), and pulsed cathodic arc. However, atmospheric arc discharge processes excel in production of stand-alone nanomaterials thanks to their high throughput and excellent quality and wide variety of obtained materials. Carbon nanostructures, like graphene and carbon nanotubes, core-shell nanoparticles, and transition metal dichalcogenide monolayers constitute some remarkable examples. Pulsed atmospheric arc nanosynthesis shows unique capabilities due to its flexibility and wide range of plasma parameters achievable by adjusting repetition frequency, pulse length, and peak values of pulse waveform. Here, we review the highlights of pulsed arc discharges applied on synthesis of low-dimensional materials, and the main contributions of this technique and other concurrent plasma methods are compared. The advantages of operating atmospheric pressure arc discharges in pulsed mode have enabled addressing instability issues via a more efficient arc control. Such milestones are discussed according to the intended research goal or application, namely: high-temperature tailoring of material nanostructure, control of deposition with a spatial resolution, nanosynthesis using liquids in plasma, and enhanced stabilization and power management of anodic arcs.

Surface morphology refinement and Laves phase control of plasma arc additively manufactured Inconel 718 via an alternating magnetic field

Improving formability and mechanical properties have always been one of the challenges in additively manufactured Nickel-based superalloys. In this work, the effect of a coaxially coupled alternating magnetic field (AMF) on surface morphology and mechanical properties of plasma arc-based additively manufactured Inconel 718 deposit were investigated. Results exhibit that the Lorentz force induced by AMF strongly alters the flow behavior of the plasma jet and the molten pool, suppressing the tendency of the liquid metal in the molten pool to flow down on the two sides face of the deposit, which in turn remarkably improved the surface accuracy of the thin-walled deposit. Furthermore, the electromagnetic stirring induced by AMF can effectively enhance the convection between the dendrites, which could not only contribute to the formation of finer dendrites but also alleviate the enrichment of the elements (i.e., Nb and Mo) at the solid–liquid interface and inhibits the precipitation of Laves phases. The smallest primary dendritic arm spacing (∼13 μm) and lowest Laves phases area fraction (3.12 %) were witnessed in the bottom region of the AMF-assisted deposit. The mechanical test confirmed that the deposit's microhardness and tensile properties were moderately improved compared with the counterpart without AMF.

SPECT-defined, active bone marrow–sparing, volumetric-modulated arc therapy reduces the incidence of acute hematologic toxicity in patients with locally advanced cervical cancer who receive chemoradiotherapy.

5527 Background: Acute haematologic toxicity is the most common side effect of chemoradiotherapy in patients with locally advanced cervical cancer.We are aim to test the efficacy of defined active bone marrow sparing volumetric-modulated arc therapy reduces grade 3 or higher (grade 3+) acute haematologic toxicity for patients with locally advanced cervical cancer treated with chemoradiotherapy. Methods: This was a prospective, single-center, open label, randomized clinical trial that enrolled locally advanced cervical cancer.Patients were randomized to 99mTc sulfur colloid SPECT-defined active bone marrow sparing volumetric-modulated arc therapy group (ABMS group) or control group.The control group received weekly cisplatin concurrently with volumetric-modulated arc therapy(VMAT),followed by high-dose-rate intracavitary brachytherapy. The active bone marrow sparing volumetric-modulated arc therapy group additionally received 99mTc sulfur colloid SPECT-defined active bone marrow dose constrain. The primary endpoint was the incidence of grade 3 or higher (grade 3+) acute haematologic toxicity. Secondary objectives included acute gastrointestinal toxicity, planning Target Volume (PTV) coverage and dosimetric parameters of organs at risk(OARs). Results: A total of 148 patients with Federation of Gynaecology and Obstetrics(FIGO) stage IB-IIIB fromJanuary 2017 to April 2019 were randomized，and 146 were treated(74 in ABMS group and 74 in control group). The median follow-up was 20.0 months.The incidence of grade 3 or higher (grade 3+) acute haematologic toxicity in the ABMS group was 29.7%,significantly lower than the 48.6% incidence in the control group(p = 0.03).The incidence of grade 3+ neutropenia (ABMS group：20.3%,control group:36.5%;p = 0.04), Grade 3+ leukopenia (ABMS group：25.7%,control group:44.6%;p = 0.02) and Grade 3+ lymphopenia (ABMS group：4.1%,control group:14.9%;p = 0.04) were significantly differences between the two group.The were no differences in Grade 3+ anemia (ABMS group：1.4%,control group:5.5%;p = 0.37) and Grade 3+ acute gastrointestinal toxicity(ABMS group：1.4%,control group:1.4%;p = 1.00) between the two group.The number of patients completing five cycles of cisplatin in the ABMS group was 88.5%,,significantly higher than the 75% in the control group(p = 0.02).There were no differences in PTV coverage and dosimetric parameters of OARs between the two group. Conclusions: SPECT-defined active bone marrow sparing VMAT signifificantly reduced grade 3+ acute haematologic toxicity,and improved chemotherapy delivery compared with control group. Clinical trial information: ChiCTR-IOR-16010214.

Surface Morphology Refinement and Laves Phase Control of Plasma Arc Additively Manufactured Inconel 718 Via an Alternating Magnetic Field

Surface Morphology Refinement and Laves Phase Control of Plasma Arc Additively Manufactured Inconel 718 Via an Alternating Magnetic Field

316L WAAM and pressure machining influence

ABSTRACTWire arc additive manufacture (WAAM) technology has a good development prospect, and can be used to manufacture large metal components with complex shapes in combination with traditional machining equipment. This paper adjusts the parameters from the perspective of heat input and arc control. It is found that the stacking quality of 316L stainless steel is the best when the arc voltage is 40V and the arc current is 360A. It is proposed to obtain the flat layers by pressure machining after every layer is stacked, which can create favorable conditions for manufacturing large-size components. And through the hot rolling experiment, it is proved that pressure machining can improve the density and uniformity of the microstructure, and thus enhance the comprehensive mechanical properties of components built by WAAM.

Features of melting high-chromium flux-cored wire in pulsed arc welding

The results of studies of the process of pulse-arc surfacing with flux-cored wire are presented. It is shown that with pulsed arc control, it is possible to increase the main parameters of the process to the values characteristic of a solid wire. The difference between the melting character of flux-cored and solid wire is shown.

Metal Transfer Mapping for Flux-Cored Arc Welding Process by Using Near-Infrared Filming

In the flux-cored arc welding (FCAW) process, the transfer of filler metal to the base material to accomplish the weld bead, determines the weld quality. It must be pointed out that the radiation emitted from the weld arc, fumes and particles (spattering) in this process represent a barrier for these studies based on the process visualization. The objective of this study is to assess metal transfer during the FCAW process of ASTM 1020 steel by filming the phenomena with assistant of near-infrared visualization, contributing to a better understanding of this process and to evaluate characteristics of metal transfer. It can clearly be seen that how the droplet is created and transferred in this process and also identify the different modes of metal transfer by changing the parameters of voltage and wire feed speed in metal transfer maps. Finally, having achieved the metal transfer maps, the suitable condition and approach for developing arc control strategies for the FCAW process were introduced.