Keyhole arc welding (KAW), including the keyhole double-sided arc welding process being developed at the University of Kentucky and keyhole plasma arc welding, can achieve much deeper narrower penetration than all other arc welding processes. If it could be controlled such that the heat input and weld pool are minimized while at the same time the desired full penetration is guaranteed, it could...

Material loss during keyhole mode laser welding often leads to surface imperfections that can negatively impact component performance. High-speed imaging identified four types of material ejection attempts: classical spatter, re-captured protuberances, and scalloping. The momentum attributed the melt body, which is influenced by properties, dictates whether attempt successful or if re-captured....

Stable weld formation is still one of the goals pursued in variable-polarity plasma arc welding (VPPAW) of aluminium alloys. Basically, VPPAW is divided into three segments: the startup segment, during which the keyhole is generated, the main body segment, during which the keyhole is dynamically maintained, and the terminal segment, during which the keyhole collapses and the crater is ®lled. Ve...

Keyhole arc welding is a cost-effective process to weld thick materials. To successfully apply this process, the state of the keyhole must be accurately detected and used in feedback control. In this paper, the dynamic behavior of the plasma reflection is described using the reflection arc angle (RAA). It is found that the RAA series can be considered an autoregressive moving-average (ARMA) pro...

Neurosurgeons have been trying to reduce surgical invasiveness by applying minimally invasive keyhole approaches. Therefore, this paper clarifies the detailed surgical technique, its limitations, proper indications, and contraindications for a superciliary keyhole approach as a minimally invasive modification of a pterional approach. Successful superciliary keyhole surgery for unruptured aneury...

Introduction The conventional keyhole data acquisition is used to permit faster imaging procedures without loss of sensitivity in dynamic studies, where initial high-resolution spatial information is combined with low-resolution spatial information at later points in time. We propose a new Fast keyhole (FK) method, which allows dynamic acquisition of a low-resolution image signal from selected ...

We consider the processing of dynamic keyhole MRI using the wavelet based approach We propsosed two wavelet based algorithms together with careful analysis The rst al gorithm embeds the conventional keyhole method as a special case in which corresponding wavelet is the Shannon wavelet while the other algorithm was proposed for the removals of the artifacts of the rst method We demonstrate that ...

In this paper, the numerical simulation of molten pool dynamics in laser deep penetration welding aluminum alloys was established based on FLUENT 19.0 software. The three-dimensional transient behavior keyhole and flow field at different speeds were analyzed, influence speed obtained. results indicated that generation spatters directly related to fluctuation diameter size middle keyhole. When i...

The process of remote laser welding is simulated in this study to identify the keyhole-induced porosity generation mechanisms and keyhole. Three processes are discussed: power levels, laser-beam shaping configurations, keyhole process. simulation finding reveals that pore development caused by strong melt flow behind As verification, equivalent experimental test also carried out. According find...