Although laser welding technology has been quickly accepted by the industrial field, the intelligent sensor technology that can realize online decision-making is still behind. Over the years, a variety of monitoring technologies that can be applied to laser pointer welding have appeared on the market.
One of the more common methods is to use a photodiode sensor to measure emissions generated during laser pointer welding (including black bodies from hot metals, reflected light from welding lasers, and in some cases plasma generated). This analysis is used to characterize the stability of the molten pool and the keyhole.
In addition, there are some additional pre-processing sensors (linear scanner, CCD-based seam tracking, tactile sensors used in wire feeding welding) and post-diagnostic analysis (linear scanner, surface inspection camera, electromagnetic sound transducer) Maker), confirm that the material can be correctly fed into the welding area, and the welding results are consistent.
But these technologies usually encounter some common limitations. Some of these technologies can only monitor the welding process but cannot perform measurements, which means that this type of technology can only be used for consistency checks. In other words, the monitoring system can inform the user that a certain welding is inconsistent with the standard sample provided by the user, but it cannot prompt the specific situation and reason of the difference and other effective information.
In addition, most sensing technologies can only monitor a single indicator during the welding process. However, it is usually necessary to sample multiple parameters to ensure the accuracy of monitoring during the entire welding process. In the context of this demand, a variety of devices need to be added in the welding station to monitor many different data, which in turn incurs more costs, and multiple systems run in parallel, which is more complex.
More importantly, none of the above techniques can provide specific information about the shape of the molten pool and keyhole below the material surface. In most cases, the internal geometry of the material ultimately determines the performance of the weld, as well as the strength (for some specific applications) and conductivity of the welding material.
Find the source of the problem. As an emerging technology in the sensor field, inline welding monitoring has solved a number of challenges that have long existed in real-time data acquisition of green laser pointer welding. This emerging technology uses a low-power infrared beam to perform precise distance measurement through an optical path coaxial with the welding laser pointer. This technology allows the measurement to be completed during the welding process. The measuring beam can be viewed at the bottom of the keyhole to directly measure the penetration depth, which is also an important feature of the new generation of welding measurement technology. The measurement result can provide a large amount of information about the entire weld, which is almost the same as the metallographic test result, within a few milliseconds, without damaging the sample itself.