Abstract
In order to improve the welding efficiency of the FNZ-125 x2 heat exchanger plates, this article introduces the design and manufacture of a new type of automatic welding machine, which can realize automatic welding of the heat exchanger plates. The design of the welding system is mainly composed of the track, locating and clamping device, power supply system and external control system. Track is the main component of the system. The track is mainly composed of the base bracket, the welding gun moving part, the walking mechanism and the precision screw device. It can provide support for the welding gun, ensure the stability and accuracy of the entire welding system, realize the movement of the welding gun, and help the position and forming of the weld. The locating and clamping device can accurately locate and clamp the heat exchangers plates. The power supply system provides reliable power supply, and the external control system provides control instructions and information feedback.In order to verify its performance, the new welding machine system was tested and found to be capable of accurately controlling the welding gun and drive motor, a stable welding process and a finished joint with a satisfactory quality.This welding machine system can meet the standard of welding FNZ-125 x2 heat exchanger plates, and it can be used for automatic production to improve the production efficiency of the heat exchanger plates.
Keywords: welding system, track, power supply, welding gun, heat exchanger plates
1 Introduction
Heat exchangers are widely used in chemical industry, environmental protection, power generation and air-conditioning systems because of their high heat transfer efficiency. FNZ-125×2 heat exchangers are mainly used in air conditioning, ventilation and refrigerator equipment. When producing FNZ-125×2 type heat exchanger plates, the welding process is complex and the quality requirements are high. Manual welding is not only inefficient, it can also cause poor welding consistency. Therefore, the development of FNZ-125×2 heat exchanger plates automatic welding machine system has become an important product in the heat exchanger industry.
This article design and manufacture a type of FNZ-125×2 type heat exchanger plates automatic welding machine system. The welding system mainly consists of the track, locating and clamping device, power supply system and external control system. The design and manufacture of the system are presented in detail in the following sections.
2 Design and structure of the welding system
2.1 Track
Track is an important part of the system and mainly consists of base bracket, welding gun moving part, walking mechanism, precision screw device and so on [1]. The base bracket is the support for the entire welding system, which can provide support for the welding gun, welding gun moving parts, walking mechanisms and other parts, so as to ensure the stability and accuracy of the entire welding system. The position and formation of the welds are completed by the movement of the welding gun, which is provided by the walking mechanism. The walking mechanism is mainly composed of two linear guide rails, which are mutually independent and drive the welding gun moving parts to move.The precision screw device is used to drive the welding gun moving parts. It is high in accuracy and wide in application range, which can meet the requirements of welding FNZ-125×2 heat exchanger plates and other parts.
2.2 Locating and clamping device
The main function of the locating and clamping device is to locate and clamp the heat exchanger plates. In order to ensure the welding accuracy and quality, the locating device should has a high positioning accuracy. The device is mainly composed of a locating plate and a clamp plate, and the locating plate and clamping plate are installed on the track respectively. The locating plate is used to locate the heat exchanger plates, and the clamping plate is used to clamp the heat exchanger plates when welding. In order to ensure the positioning accuracy of the plates, the two plates are driven by precision stepping motor.
2.3 Power supply system
The power supply system is an important part of the welding machine. The welding generator used in the system is a medium frequency power supply with characteristics of automatic voltage regulation and high waveform stability. Meanwhile, the system are equipped with water cooling device to ensure the working condition of the welding generator.
2.4 External control system
The external control system provide the control instruction and information feedbacks. The computer plays a role in the system and provide control instructions as well as information feedbacks. The system can realize the control of the welding gun and motor drive, furthermore, the prameters of the welding process and the quality of the finished weld joint can be monitored.
3 Performance test
In order to verify the performance of the new welding system, the authors of this paper conducted a series of performance tests. Firstly, the floating speed of the welding gun is tested, which is 19.2 cm/min. A stable welding process is provided due to the precise control of the welding gun and drive motor.
In order to verify the stability of the welding process, we carry out the welding rehearsal experiment, and use the industrial camera to monitor the welding process. The results show that the welding gun can accurately follow the tracks, the speed is stable and the welding torch head can accurately forms the weld.
In order to test the quality of the welded joint, we select the finished joint and perform a tensile strength test. The results show that the tensile strength of the weld is up to 120MPa, which meets the requirements of the standard.
4 Conclusion
This paper design and manufacture a type of FNZ-125×2 heat exchanger plates automatic welding machine system. By means of performance tests, the new welding system can accurately control the welding gun and the drive motor, realize a stable welding process and the finished joint has a satisfactory quality. This welding machine system can meet the standard of welding FNZ-125×2 heat exchanger plates, and it can be used for automatic production to improve the production efficiency of the heat exchanger plates.
