Development Of High Speed Dynamic Temperature Measurement System For Welding Head

Temperature is an important basic parameter used to characterize the characteristics of objects.It is widely used in various fields such as metal processing,production and life,aerospace,etc.The accuracy of temperature measurement has a vital impact on every industry.As the specifications of electronic devices develop toward precision and miniaturization,and the production of electronic products is moving toward automation and speed,there are more and more unqualified products due to welding temperature fluctuations.Therefore,how to obtain the temperature of the welding head during welding in real time has attracted more and more attention from enterprises and has become an urgent problem to be solved.Due to the complexity of the welding head welding process,most scholars at home and abroad are currently conducting theoretical simulation calculations,which is far from the actual value.Therefore,how to directly obtain the temperature of the welding head during welding and then evaluate the welding quality is of great significance to industrial production.In response to the requirements of the project,this paper developed a set of transistor-type welding power source welding head temperature rapid measurement system with a temperature range of 300?-800?.The feasibility of contact and non-contact temperature measurement methods commonly used in the field of temperature measurement is analyzed,and the infrared radiation temperature measurement method to solve the problem of welding head temperature measurement is proposed in this paper.The advantages and disadvantages of the brightness temperature measurement method,the colorimetric temperature measurement method and the total radiation temperature measurement method in the infrared radiation temperature measurement are compared,and the system design is based on the brightness temperature measurement method.Through the analysis of the welding head structure,the black body method is used for temperature measurement,and the real temperature of the welding head is obtained by measuring the small hole at the front end of the welding head.The entire temperature measurement system is composed of a hardware part and a software part.Among them,the hardware part includes the design of the optical system,the selection of the detector,the I/V conversion and amplifying circuit,the data acquisition and display system of the single-chip computer,and the high-speed data acquisition system of the host computer.In the software part,it mainly includes the software design of the single-chip microcomputer and the software design of the upper computer.The software of the single-chip microcomputer adopts C language for programming,which mainly includes AD acquisition,filtering,OLED drive,temperature calculation and serial communication.The upper computer software part adopts Labview for programming,which mainly includes the configuration and drive of AD acquisition card,data filtering,zero point measurement,temperature calibration,temperature calculation,real-time temperature curve and data storage.After the system is built and the software is debugged,the standard cavity blackbody furnace is used for temperature calibration.First,the overall blackbody method is used to experimentally verify the emissivity value provided by the demander,and the measured emissivity values when oxidized and unoxidized are consistent with the values in the literature.Then use this emissivity value to calculate the cavity black body emissivity of the small hole on the welding head.Finally,a constant output transistor type welding power source is used to continuously emit heat for system stability testing and repeatability experiments.Finally,after calculation,the overall system uncertainty is less than 3%.