Method for controlling welding shielding gas flow

Abstract

The invention discloses a method for controlling welding shielding gas flow, which is characterized in that the required shielding gas flow can be set according to factors such as welding posture and welding current, and the output of different flow gas flows can be increased by increasing the path number of input switching value signals. The problem that different shielding gas flows cannot be set according to current and postures in the previous multi-weld-bead welding process is solved. The system can automatically adjust the duty ratio of the PWM signal according to the signal fed back by the flow detector to form a closed loop. And when the gas flow setting requirement cannot be met after automatic adjustment, the equipment outputs an alarm signal to an upper computer, and the upper computer is ensured to master the gas supply condition of the welding shielding gas.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a method for controlling the flow rate of shielding gas during welding. Background Art

[0002] The existing welding shielding gas control method in the world is valve switch control, that is, when the welding station needs gas supply, the valve is opened to supply gas, and when the welding shielding gas is not needed, the valve is closed. When there are multiple welding currents and welding angles in the same station, the same shielding gas flow rate is still used for gas supply. In order to ensure the welding quality, when there are different welding currents and welding angles, the maximum shielding gas flow rate needs to be selected as the gas supply flow rate of the station, resulting in a large amount of waste of welding shielding gas. Summary of the invention

[0003] like Figure 1 As shown, the method of the present invention is: the electrical signal transmission process is: the switch quantity sent by the host computer (robot or PLC) is converted into a corresponding PWM signal through the logic circuit (1), and the signal is transmitted to the PWM proportional valve (2) through the signal line; (2) is connected to the flow detector (3) through a pipeline; the flow state signal output by the flow detector (3) is connected to the logic circuit (1) through the signal line; the flow state signal output by the flow detector (3) is connected to the host computer through the signal line; the host computer signal line and power line are connected to the logic circuit through corresponding cables.

[0004] The protective gas transmission path is: the external gas source transmits the protective gas to the PWM proportional valve (3) through the gas pipe; the PWM proportional valve (3) transmits the protective gas to the flow detector (3) through the gas pipe; and the flow detector (5) transmits the protective gas to the gas-using equipment through the gas pipe.

[0005] When the flow detector (3) outputs the welding shielding gas flow value to the logic circuit (1) in real time through analog quantity, when the welding shielding gas flow value is lower than the set value, the logic circuit (1) increases the duty cycle of the output PWM signal. If the set welding shielding gas flow rate is still not reached after the PWM signal duty cycle is increased, the logic circuit (1) sends an alarm signal to the upper computer. The flow detector can also feed back the instantaneous flow rate and the accumulated flow rate to the logic circuit.

[0006] The main control method of the logic circuit is to match the input of several switch quantities to the PWM signal of the corresponding duty cycle, that is, to realize the switch quantity input, PWM quantity output, and then control the function of the proportional valve. By increasing the PWM signal to an intermediate quantity, the function of using the switch quantity to complete the proportional output of the proportional valve is realized. The logic circuit also receives the flow signal fed back by the flow detector, and automatically adjusts the output PWM signal duty cycle according to the feedback value to realize closed-loop control.

[0007] The method for controlling the flow rate of welding shielding gas is characterized in that the required shielding gas flow rate can be set after comprehensive consideration of factors such as welding posture and welding current, and the output of different flow rates of gas can be increased by increasing the number of input switch signals. For example, two switch quantities can correspond to the output of 4 different shielding gas flow rates, and three switch quantities can correspond to the output of 8 different shielding gas flow rates. The system can automatically adjust the size of the PWM signal duty cycle according to the signal fed back by the flow detector to form a closed loop. When the set gas flow requirement still cannot be met after automatic adjustment, the device outputs an alarm signal to the host computer to ensure that the host computer is aware of the welding shielding gas supply situation.

[0008] According to the requirements of the host computer, the logic circuit feeds back the instantaneous flow and accumulated flow to the host computer so that the host computer can manage the relevant data.

[0009] Beneficial effects of the present invention:

[0010] In the process of welding shielding gas flow control, the switch signal sent by the host computer is converted into a PWM signal that can control the proportional valve, so as to provide corresponding welding shielding gas flow for different welding currents and welding angles, which solves the problem that different shielding gas flow rates cannot be set according to current and posture in the previous multi-pass welding process, thereby saving the use of welding shielding gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0012] Instructions attached Figure 1 It is a schematic diagram of the main logic and hardware structure of the present invention, showing a method of controlling the flow rate of welding shielding gas according to different welding angles, welding currents and other working conditions through a robot and a logic circuit.

Claims

1. For specific welding requirements, the host computer (robot or PLC) sends out the corresponding switch signal. After receiving the signal from the host computer, the logic circuit outputs the PWM signal with the corresponding duty cycle to control the flow of welding shielding gas. The flow detector feeds back the real-time flow signal to the logic circuit for closed-loop control.

2. The main control method of the logic circuit is to match the input of several switch quantities to the PWM signal of the corresponding duty cycle, that is, to realize the switch quantity input, PWM quantity output, and then control the function of the proportional valve. By increasing the PWM signal to an intermediate quantity, the function of using the switch quantity to complete the proportional output of the proportional valve is realized. The logic circuit also receives the flow signal fed back by the flow detector, and automatically adjusts the output PWM signal duty cycle according to the feedback value to realize closed-loop control.

3. The method for controlling the welding shielding gas flow rate is characterized in that the required shielding gas flow rate can be set after comprehensive consideration of factors such as welding posture and welding current. That is, in the process of controlling the welding shielding gas flow rate, this method takes into account both the requirements of the welding current for the shielding gas flow rate and the requirements of the welding posture for the shielding gas flow rate.

4. This method can increase the output of different flow rates of gas by increasing the number of input switch signals. For example, two switch signals can correspond to the output of 4 different shielding gas flow rates, and three switch signals can correspond to the output of 8 different shielding gas flow rates.

5. The protective gas transmission path is: the external gas source transmits the protective gas to the PWM proportional valve (3) through the gas pipe; the PWM proportional valve (3) transmits the protective gas to the flow detector (3) through the gas pipe; the flow detector (5) transmits the protective gas to the gas-using equipment through the gas pipe.

6. Change the PWM signal corresponding to the switch signal sent by the host computer to other non-PWM signals that can control the proportional valve, such as analog signals. Because their specific control logic is the same as this method, they should be regarded as the same method as this method.

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