Multisensor-based monitoring of weld deposition and plate distortion for various torch angles in pulsed MIG welding

Manufacturing companies often fail to maintain good weld quality due to poor arc stability and distortion after welding. Weld quality can be improved by reducing the transverse shrinkage and the angular distortion in butt welding. The welding deposition efficiency is also an important economic factor. In this work, various pulse voltage parameters have been varied along with welding torch angle in pulsed metal inert gas (P-MIG) welding. The experimental results revealed that the peak voltage is the dominant pulse voltage parameter. Various sensors were also used to monitor arc current, arc voltage, arc sound, and also weld temperature. A strong relationship between arc sound (as well as arc power) and transverse distortion (as well as metal deposition) was found to exist in P-MIG welding. The frequency domain features of welding arc sound were also extracted and correlated to the process characteristics.     

Prediction and optimization of weld bead geometry in oscillating arc narrow gap all-position GMA welding

The International Journal of Advanced Manufacturing Technology - Oscillating arc narrow gap all-position gas metal arc (GMA) welding is primarily applied for the construction of large metal...     

Adaptive chirplet transform for sensitive and accurate monitoring of pulsed gas metal arc welding process

Condition monitoring of welding processes have received considerable attention in recent years. The method proposed in this paper provides a novel and a better method for analysis of the weld joint strength, i.e., the adaptive chirplet transform. The presence of the nonlinearities in the various sensor outputs of the monitoring systems of the welding procedure demands a more precise signal processing method for a more accurate analysis of the weld joint strength. The adaptive chirplet method has been used here which produced much better results than the other statistical signal processing methods like the wavelet transform technique due to a better time–frequency resolution of the same. In nonlinear feature extraction, wavelet transform technique was first used to detect the weld joint strength using current as a sensor output during the welding. Then the similar procedure was followed using the adaptive chirplet analysis technique which not only showed better differencing capacity between various signals but also provided better time–frequency resolution for the experimental cases where the wavelet method could not predict the weld joint strength correctly. A thorough laboratory study shows that the diagnostic method proposed in this paper is much more accurate, has high sensitivity with respect to faults, and also has better diagnostic resolution.     

Feature extraction and dimensionality reduction of arc sound under typical penetration status in metal inert gas welding

Arc sound is well known as the potential and available resource for monitoring and controlling of the weld penetration status,which is very important to the welding process quality control,so any atten...     

Microstructure and joining mechanism of Ti/Al dissimilar joint by pulsed gas metal arc welding

Butt joining of titanium alloy Ti–2Al–Mn to aluminum 1060 using AlSi5 filler wire was conducted using pulsed gas metal arc welding. Joining mechanism of Ti–2Al–Mn/Al 1060 dissimilar joint with different welding heat input was investigated. Formations of precipitation and Ti/Al interface were discussed in detail. Fusion zone near aluminum is composed of α-Al dendrites and Al–Si hypoeutectic structures. A few TiAl₃ precipitations appear in the weld metal owing to metallurgical reactions of Al with dissolved Ti. When the welding heat input was in the range of 1.87–2.10 kJ/cm, titanium alloy Ti–2Al–Mn and Al 1060 were joined together by the formation of a complex Ti/Al interface. With a low welding heat input, a serrate TiAl₃ interfacial reaction layer was formed near Ti/Al interface. With the increasing of the welding heat input, α-Ti, Ti₇Al₅Si₁₂, and TiAl₃ layers were formed orderly from Ti–2Al–Mn to weld metal.     

Multi-objective optimization of pulsed gas metal arc welding process based on weighted principal component scores

Most welding processes present large sets of correlated quality characteristics. With this particularity in mind, we present a multi-objective optimization technique based on Principal Component Analysis (PCA) and response surface methodology (RSM). This two-fold technique utilizes PCA to factorize the original welding responses. The original responses—obtained through a Central Composite Design—are then replaced by the resulting principal component scores. The technique’s advantage is that it reduces the data set and still considers the correlation among the responses. Quite often, however, the first principal component alone cannot explain the amount of variance–covariance structure of the welding responses. In this paper, we remedy this shortfall by proposing an objective function established in terms of the most significative principal component scores (weighted by their respective eigenvalues). Experimental results were obtained with a multiresponse pulsed gas metal arc welding process. These results, when compared with other strategies of multiresponse combination, verify the adequacy of our proposed approach.     

空间焊缝弧焊机器人焊接路径自动规划研究

开发了面向空间焊缝的弧焊机器人焊接路径自动规划系统。该系统以VB6．0为编程平台，能够实现由三维实体模型直接生成机器人焊枪的位姿文件，进一步地输出为机器人语言程序，采用UP6弧焊机器人系统和S-350MAG焊接系统实际焊接，实验结果验证了该系统的正确性。     

手工电弧焊电弧电压控制的研究

采用手工电弧焊进行焊接时，电弧电压是一个很难控制的工艺参数。有时对焊接质量产生较大影响。本文针对职业技术类院校焊接专业学生在进行手弧焊实训时难以控制弧长（电弧电压）的问题提出一种解决方案——设置超压报警系统。当弧压增大到超过预设值时，系统报警提醒操作者调节弧长，从而将电弧电压控制在预设值之下。     

Effect of forces on dynamic metal transfer behavior of cable-type welding wire gas metal arc welding

A cable-type welding wire (CWW) gas metal arc welding (GMAW) method was proposed as a novel approach, using CWW for the consumable electrode. Droplet transfer influences the welding process, and the forces on the droplet were analyzed to elucidate the metal transfer phenomenon observed during the welding process. The effects of the arc pressure, rotating force, and welding parameters were analyzed to understand the metal transfer. The special structure of the CWW affected the arc characteristics and forces during metal transfer as part of the welding process. The droplet formed by droplets from each thin wire, the arc, and electromagnetic forces on droplet formation and the coupling process were analyzed. The arc pressure and rotating forces are beneficial to metal transfer and increase the droplet transfer frequency. The droplet size decreases with increasing welding parameters.     

一种基于DSP的焊缝跟踪模糊控制器系统的设计

本文阐述了焊缝跟踪参数自整定模糊控制器的工作原理．提出了比例因子和量化因子自动调节的方案和实现方法．介绍了模糊控制器的具体设计步骤和DSP参数自整定模糊控制系统的硬件．软件设计，结果表明，在焊缝跟踪中采用参数自整定模糊控制可以明显改善系统的性能。     

Joint strength prediction in a pulsed MIG welding process using hybrid neuro ant colony-optimized model

In this work, a pulsed metal inert gas welding (PMIGW) process is modeled by using a hybrid soft computing technique. Ant colony optimization (ACO) and back-propagation neural network (BPNN) models are combined to predict the ultimate tensile strength of butt-welded joints. A large number of experiments have been conducted, and comparative study shows that the hybrid neuro ant colony-optimized model produces faster and also better weld-joint strength prediction than the conventional back propagation model.     

塞拉门弧焊机器人工作站柔性焊接夹具设计

以手工焊接的塞拉门铝镁硅合金框架为研究对象，在安川UP6工业机器人本体及辅助装置基础上，进行塞拉门铝镁硅合金框架弧焊机器人工作站的研发，针对塞拉门规格型号繁多的特点，设计塞拉门柔性焊接夹具，以实现机器人工作站的高质、经济与高效。     

Comparative study of toughness between the AH 40 fatigue crack arrester steel and its weld metal in the case of robotic metal-cored arc welding

The current investigation aims to scrutinize the impact and fracture toughness of the AH 40 fatigue crack arrester (FCA) steel and its weld metal, when welded with the metal-cored arc welding technique (MCAW). Initially, macroscopic observation and microstructural characterization were carried out in the areas of interest. Subsequently, the impact toughness was determined with the use of the Charpy V-notch test (CVN) at various temperatures, while the values of the absorbed energy (KV), the percentage of shear fracture (PSF), and the lateral expansion (LE) were recorded. Moreover, the ruptured surfaces were examined with a scanning electron microscope (SEM). Finally, the crack tip opening displacement (δ) parameter was estimated at room temperature by fracture toughness testing. The obtained data led to the quantification of the toughness parameters, when dynamic or quasistatic load is applied, while the combined effect of several factors to the degradation of the weld metal toughness was elucidated. The ductile to brittle transition curve and the crack tip opening displacement in the weld metal appeared to be lower than inside the unaffected material. Nevertheless, fracture toughness properties were evaluated within acceptable limits in all cases.     

Wire melting rate of alternating current gas metal arc welding

The wire melting phenomenon in alternating current gas metal arc welding (AC-GMAW) process should be carefully observed and analyzed since it is one of the most important representative characteristics of GMAW process. In this study, a new form of wire melting rate equation for AC-GMAW process is proposed based on energy conservation theory and arc physics. Using experimental data, the wire melting rate coefficients of AC-GMAW are obtained through nonlinear regression analysis. The wire melting rate is influenced not only by the current waveform, electrode polarity, and droplet size but also by the shape of the wire tip. That is, if the wire tip becomes more slender, arc heating has more influence on the wire melting. Using the wire melting rate proposed in this research, the uncertainty of calculating wire melting rate coefficients of AC-GMAW can be excluded comparing to existing method.     

Experimental study and numerical modeling of arc and weld pool in stationary GTA welding of pure aluminum

In this study, a 2D mathematical model was developed for both arc and weld pool in stationary GTA welding. In arc model, current continuity equation has been solved in both arc and cathode regions without any assumption of fixed current density on the cathode surface which was essential in most previous works. The results of arc model were presented for both copper and aluminum anodes to investigate the effect of anode material on arc properties. It was seen that aluminum anode has lower maximum anode current density and heat flux but the distributions are wider than copper anode. Furthermore, shear stress on anode surface is higher in the case of aluminum anode. Also, calculated results of this study were compared with other available theoretical and experimental results. It has been shown that the agreement between calculated and experimental results was fairly good. The necessary information to simulate the weld pool, including the anode current density and heat flux to the workpiece were taken from the arc model. In this model, due to high thermal conductivity of pure aluminum, fluid flow into the weld pool was ignored. Effects of arc variables, i.e., arc length, applied current and welding time on the shape and size of the weld pool were investigated as well. In order to check the validity of the weld pool model, a comparison between calculated results and the results of our experimental tests was conducted. Generally, these comparisons reveal an acceptable agreement between calculated results and experimental data.     

Optimisation of the weld bead geometry in gas tungsten arc welding by the Taguchi method

In this paper, determination of the welding process parameters for obtaining an optimal weld bead geometry in gas tungsten arc welding is presented. The Taguchi method is used to formulate the experimental layout, to analyse the effect of each welding process parameter on the weld bead geometry, and to predict the optimal setting for each welding process parameter. Experimental results are presented to explain the proposed approach.