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《Science & Technology of Welding & Joining》2013,18(7):563-570
AbstractComputation of the electromagnetic force over a wide range of consumable arc welding parameters is difficult with available models because of the need for experimentally evaluated electrode extension for every individual set of parameters. This becomes more complicated in case of submerged are welding, because the welding arc remains buried beneath flux. This study presents a new approach of integrating mechanistic model of electrode extension with the computational model of electromagnetic force, wherein the apparent electrode extension is obtained by solving the electrode melting rate equation. The proposed approach is demonstrated through a case on submerged arc welding. The effect of current, voltage, electrode diameter, contact tip to workpiece distance and polarity, on the electromagnetic force, is determined and analysed. This investigation shows that detrimental effects of welding electromagnetic force can be restricted without compromising productivity because after initial rapid increase, no considerable change in melting rate is caused by the force under consideration. 相似文献
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电压近似熵-SVM铝合金双丝PMIG焊过程稳定性评价 总被引:2,自引:2,他引:0
提出了弧压信号近似熵-支持向量机(support vector machine,SVM)算法来评价铝合金双丝脉冲熔化极惰性气体保护(pulse metal insert gas,PMIG)焊焊接过程稳定性,并经试验验证该方法具有可行性和一定的可靠性.铝合金双丝PMIG焊电流、电压信号近似熵值越大对应焊接过程越不稳定,且相比于电流近似熵值,电压近似熵值能更加明确的表现焊接过程稳定性的差异,所以选取电压近似熵值进行SVM分类.结果表明,文中数据情况下,训练数据集在20%以上时分类准确率均在90%以上,且训练数据越充足分类结果越准确. 相似文献
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分别采用正弦波变极性和方波变极性氩弧焊对铝合金试板进行了焊接试验,利用高速摄像机和汉诺威分析仪分别对焊接过程中变极性电弧形态及电信号进行采集分析. 结果表明,电弧电压概率密度分布和高速摄像图证实了较小焊接参数条件下正弦波变极性比方波变极性电弧稳定性差的现象. 正弦波变极性TIG电弧随EP(反极性)的增加清理宽度增加,但熔宽未增加,证明此条件下正弦波变极性TIG电弧过于发散;焊接参数较大时,随EP的增加,正弦波变极性熔宽变宽,证实正弦波变极性TIG电弧稳定性随之提高,证明了铝合金变极性TIG焊接过程中EP极性电弧产热大于EN极性电弧能量的本质特征. 相似文献
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采用多信息融合技术对激光-双电弧脉冲复合焊在不同双丝间距下的电流信号、电压信号、高速摄像信号进行同步采集,研究双丝间距对焊接过程的电弧行为、熔滴过渡过程及焊缝表面成形的影响,并依据混沌理论和算法,从非线性角度对激光-双丝脉冲MIG焊接过程的电流信号进行了最大Lyapunov指数(LE)计算.结果表明,激光-双丝脉冲MIG焊接过程是一个混沌过程,由于激光光致等离子体和电弧等离子体的相互作用改变电弧的形态和熔滴受力状态,进而影响焊缝成形,在一定的焊接工艺参数下存在最佳双丝间距,在最佳双丝间距下,电弧稳定,焊缝成形良好,且此时最大LE值及其标准方差最小. 相似文献
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Wen-Hou Chu Pi-Cheng Tung 《International Journal of Machine Tools and Manufacture》2005,45(7-8):933-939
This paper describes the development of an automatic welding control system for alternating current shield metal arc welding. This method could replace manual operations which require a well-trained technician. We have derived a mathematical model of the welding control system and identified system parameters. An adaptive sliding mode controller, estimates the bound of uncertainties, and modulates the rate of the electrode feed mechanism that regulates the arc current. The electrode feed-rate mechanism with this controller is driven by an AC servomotor, which can compensate for both the molten part of the electrode and undesirable fluctuations in the arc length during the welding process. The method can be easily applied to any welding system in which the electrode is consumed during the welding process. By maintaining the magnitude of the arc current at the desired value and the stability of the arc length, excellent welding performance is obtained. The simulation and the experimental results both show that this automatic welding control system, based on the adaptive sliding mode controller, can perform effectively. 相似文献
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利用焊接电弧电压信号的标准差和差异系数的倒数作为评价电弧稳定性的指标,通过试验研究了不同工艺条件下水下湿法药芯焊丝焊接的电弧稳定性.建立了湿法焊接电弧稳定性的敏感度模型,分析了各工艺参数如焊接电流、电弧电压、焊接速度和水深对湿法药芯焊丝焊接电弧稳定性的影响.结果表明,水深增大时,焊接电弧稳定性变差,特别是在浅水区域,增大水深可显著降低电弧稳定性;焊接速度增大,电弧稳定性变差;焊接电压对电弧稳定性影响很大,适当提高焊接电压可提高电弧的稳定性. 相似文献
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文中利用侧向风场的吹袭作用来抑制横焊熔池的下淌,研究了在侧向风场作用下焊缝成形质量和旋转电弧的传感特性. 提出了一种基于平面拟合的焊枪偏差和电极高度检测算法,实现了同一电流信号下焊枪偏差和电极高度的同时检测. 结果表明,适当控制侧风流量有助于抑制熔池下淌、改善焊缝成形. 但是随着风速的增加,焊接电弧的熄弧率升高、电弧传感的准确性降低. 针对焊接电流的噪声干扰,还设计了软阈值小波滤波算法,并开发了相应的模糊控制算法对焊枪偏差和电极高度进行调节,初步实现了横焊焊缝的成形控制和跟踪. 相似文献
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针对焊接稳定性定量评定困难的特点,提出了一种基于电流样本熵的焊接稳定性评定方法. 随着电信号稳定性降低,样本熵均值变大,样本熵标准差也变大,选用样本熵的均值与标准差的乘积来量化焊接稳定性. 讨论了嵌入维数、给定阈值和样本长度对样本熵的影响,对于研究的脉冲MIG焊电流信号,当m=2, r=0.08, N=2 000时,样本熵分布合理,计算所耗时间较小.最后做了三组脉冲MIG焊对比试验. 结果表明,通过样本熵的均值与标准差的乘积评定的焊接稳定性与实际焊缝质量效果吻合;在相同给定电流下,样本熵的均值与标准差的乘积越大,焊接稳定性越差. 相似文献
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The characteristics of welding currents in a rotating arc lead tandem GMAW process and the weld-seam tracking 下载免费PDF全文
Tandem gas metal arc welding (T-GMAW) process shows a high deposition rate that up to three times of the single electrode GMAW,so the welding speed could be significantly increased in this process.However,the majority of this process applications are based on the pre-programmed robotic welding,which does not allow them to track the seam real-time during welding.Rotating arc sensor,sensing the seam position by detecting the changing of welding currents,has been widely adopted in the automatic robot welding process.It is proposed in this paper to integrate the rotating arc sensor with a trailing torch to develop a new approach of rotating arc lead tandem gas metal arc welding (RLT-GMAW) process.The characteristics of the welding currents in the proposed new welding process were firstly studied,and then a self-turning fuzzy control seam tracking strategy was developed for the mobile robot automatic welding.The experimental results showed that the proposed RLT-GMAW process had an excellent seam tracking performance and high welding deposition rate.Even if there were some electromagnetic interactions between the two arcs,the deviation of the welding seam could also be reflected by the fluctuation of the welding currents on the leading arc once the correct welding parameters were selected.Based on the detected deviation,the welding tracking experiments showed that the proposed self-turning fuzzy controller had a good performance for the RLT-GMA W process seam tracking. 相似文献
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ABSTRACTSpecial features of the process of shunting plasma arc current with a consumable electrode are investigated. The effect of the diameter of the consumable electrode, its visible extension and plasma arc current on the shunting current is determined. The effect of shunting current on the electrode metal transfer and the rate of electrode melting is determined. 相似文献
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H.E. Beardsley Y.M. Zhang R. Kovacevic 《International Journal of Machine Tools and Manufacture》1994,34(8):1079-1090
The objective of this study is to present an applicable top-side infrared sensing technique for the prospective closed-loop control of weld penetration in gas tungsten arc welding (GTAW). A model is developed to calculate the full penetration state, which is specified by the back-side bead width, from the sensed infrared images. To ensure the model validity in the prospective closed-loop control, the experiments, which generate the data for the model identification, are conducted under the experimental conditions that will be encountered during practical closed-loop control of the welding process. The heat transfer condition and electrode tip angle may vary during welding or from case to case. Also, the control variables which are used to adjust the weld process in order to reach the required weld penetration will also change. In many cases, the current can be employed as an on-line adjustable control variable because of the implementation ease, when the welding speed and arc length are maintained at the preset values. Thus, different currents, workpiece sizes, and electrode tip angles are arranged in the experiments to emulate the possible current adjustments, case to case heat transfer variations, and electrode wear. The infrared characteristics of the effects of these parameters are extracted to regress the full penetration state. Finally, the back-side weld width (the full penetration state) is calculated using the resultant model from the sensed infrared data. 相似文献
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交流脉冲MIG焊其焊缝熔深及焊丝熔化速度不仅与焊接电流有关,而且与负极性比率有关。当负极性比率等于零即直流且焊丝为正极性的MIG焊时,其焊缝熔深最大,焊丝熔化系数最小,熔敷速度最小;随着负极性比率增加,焊缝熔深减小,同时焊丝熔化系数增加,熔敷速度增加。交流脉冲MIG焊接铝合金薄板时,通过调整焊接电流及负极性比率,形成浅焊缝熔深的同时,形成较高的熔敷速度,从而可以提高焊接速度,避免出现烧穿及熔池下塌现象,保证焊接质量。 相似文献