Research And Implementation Of Laser Welding Quality On-line Detection Technology Based On Photoelectric Signal

Laser welding technology is a new welding technology after the invention of laser in the 20 th century.With the advantages of high welding efficiency,good welding quality and highspeed welding,it has been widely used in the fields of national defense,shipbuilding,automobile and electronics.The laser welding process is a multi-variable and highly complex process,which is affected by many accidental unstable factors,resulting in the change of the unstable state of the welding position,welding defects and other problems.The welding defect problem will not be able to meet the high quality requirements of modern laser welding industrial production process.Therefore,it is of great significance to establish a laser welding quality on-line detection system based on photoelectric signal for real-time detection and feedback of welding process changes.In this paper,the related work of laser welding quality inspection is studied in depth.The basic physical characteristics of laser welding include keyhole formation,molten pool,metal vapor,plasma generation,etc.The welding process produces a series of signals which can be used to indirectly reflect the welding quality,including optical signals,acoustic signals,electromagnetic signals and so on.The paper adopts the optical signal generated in the welding process as the detection signal,which includes the following three forms of optical signals: visible light emitted by the plasma state,infrared light signal emitted by the metal solution and reflected laser light signal.The change of three-channel detection signal is easily affected by laser welding process.The relationship between the physical state which mainly affects the change of laser welding process and laser welding process is studied.In addition,in order to improve the accuracy and precision of photoelectric signal detection,the detection system combined with the existing laser galvanometer system and collimation system,redesigned the optical transmission channel of optical signal.The pulse square wave welding method is used for photoelectric signal detection system feasibility test,by changing the parameters of a single welding process design for three groups of test samples test,using the statistical data processing method,the welding material process of test in the test effect to determine and test detection software statistical comparison with the test data to determine the results of processing,welding material and the data graph is established,the relationship between the database and to establish a test.The classification results of welding defects were analyzed through welding test products,and whether the welding results were qualified or not was judged,and the accuracy rate and error rate of laser welding quality were counted and analyzed.The mechanical structure of on-line inspection equipment for laser welding quality is designed,and the selection of hardware is introduced,which includes motion control card,data acquisition card,industrial computer and photoelectric detector.According to the hardware equipment used,the detection software for real-time detection is developed.Detection software is running on Windows 7 system platform,software USES the multi-channel signal acquisition and analysis,processing,preservation,such as program design,software interface is simple and practical operation is simple and easy to debug and ensure the quality of laser welding test is the use of high efficiency,welding quality of real-time detection system of online measuring target.The on-line inspection system of laser welding quality based on photoelectric signal reduces the outflow of defective welding products and has practical reference value in laser welding industry.