Monitoring Technology and Application of Mid-frequency Spot Welding Machines

To achieve better monitoring results, it is essential to correctly select the parameters for acoustic emission monitoring in mid-frequency spot welding machine monitoring equipment. These parameters include: main amplifier gain, welding threshold level, spatter threshold level, crack threshold level, crack delay time, cracking time, frequency window, time window, etc. These parameters should be selected based on the acoustic emission characteristics of welding, spatter, and cracks.

Specifically, the first four parameters are mainly selected based on the position of the acoustic emission signal on the time axis and the magnitude of the signal amplitude. The main amplifier gain should be appropriately coordinated with the threshold value. It should not be assumed that higher gain is better, and lower threshold values are better.

The frequency window refers to the center frequency of the transducer and filter and the different frequency response characteristics. Different environments have different interference signals, so the selected frequency window should be able to receive the richest acoustic emission signals while avoiding interference.

The time window is set to eliminate interference signals from the input acoustic emission signal. It is crucial to adjust the logic control gate for opening and closing the gate and the required time frequency window and time window selection. It should be tested, analyzed, and understood the characteristics of the acoustic emission source and environmental noise sources before making a satisfactory choice.

During spot welding, due to the intense melting and gasification of the coating in the welding area, accompanied by spatter in the initial stage of welding, large burst-type acoustic emission signals are generated within the first cycle of spot welding, but these signals have little to do with the formation of the weld nugget.

Therefore, the time window should be pre-adjusted so that no acoustic emission signals are received within the first cycle. Another characteristic of spot welding galvanized steel plates is the intermittent large amplitude acoustic emission pulses in the late stage of spot welding, caused by the gasification of residual zinc in the welding area. At this time, the time window should be adjusted to eliminate these large acoustic emission pulses.

This time window should be closed to prevent the generation of unrealistic monitoring. Based on this technology, the relationship between the diameter of the weld nugget and the acoustic emission energy count during spot welding of galvanized steel plates is established.

Suzhou Agera Automation Equipment Co., Ltd. specializes in the development of automated assembly, welding, testing equipment, and production lines, primarily serving industries such as household appliances, automotive manufacturing, sheet metal, and 3C electronics. We offer customized welding machines, automated welding equipment, and assembly welding production lines according to customer needs, providing suitable overall automation solutions to assist companies in quickly transitioning from traditional production methods to high-end production methods. If you are interested in our automation equipment and production lines, please contact us: leo@agerawelder.com