The determination of quality parameters of resistance spot weld in real time is of great importance in today’s industry. Acoustic waves can solve this problem in the sense of measuring certain features directly related to the weld quality – degree of heating of the weld zone, moment of beginning of melting and some others. The ultrasonic transducer incorporated into an electrode sends short aco...

Recently developed optical inspection tools provide images from the inside of natural gas pipelines to monitor pipeline integrity. The vast amounts of data generated prohibits human inspection of the resulting images. We designed an image processing and classification method to identify abnormal events. Non-overlapping image blocks are classified into twelve categories: normal, black line, grin...

Automated monitoring and control of the weld pool surface has been one of the goals of the welding industry. This paper presents a technique which uses a calibrated charge-coupled device (CCD) sensor and structured light to extract the surface information as depth of pool from captured images. It projects a laser line from a pre-determined position onto the specular weld pool surface. A reflect...

Improved product quality and production methods, and decreased production costs are important objectives of industries. Welding processes are part of this goal. There are many studies about monitoring and controlling welding process. This work presents a non-intrusive on-line monitoriment system and some algorithms capable of detecting GTAW weld defects. Some experiments were made to simulate w...

Resistance spot welding is one of the most widely used processes in sheet metal fabrication. Improvements in quality assurance are important to increase welding productivity. Until now, quality estimation was performed using dynamic resistance at the secondary circuit, which is easily measured. However, this method has many problems when applied to in-process real-time systems. In this study, w...

This paper addresses the problems involved in the automatic monitoring of the weId quality produced by robotized short-arc welding. A simple statistical change detection algorithm for the weld quality, the repeated Sequential Probability Ratio Test (SPRT), was used. The algorithm may similarly be viewed as a cumulative sum (CUSUM) type test, and is well-suited to detecting sudden minor changes ...

For hot extrusions of magnesium alloy sheets, Dissimilar AZ80 and AZ31 were used, in which AZ80 was placed on advancing side and AZ31 on retreating side, using friction stir butt welding with different process parameters. Some defect-free welded joints with good weld surfaces could be obtained with some suitable welding conditions. The maximum tensile strength of welded joint which is 225.5 MPa...

Laser welding has a quite high demand on trajectory accuracy of articulated robot. To improve dynamic trajectory accuracy of articulated robots for laser welding, a novel 3D seam tracking method is proposed based on stereo visual feedback control. The method constructs a visual feedback control system with two convergent cameras mounted at the end of industrial robot. A tool coordinate system i...