JPS63188473A - Arc welding equipment - Google Patents

Abstract

PURPOSE:To obtain the proper welding output even in the high-speed welding by selecting an optimum value from among the data stored in a welding condition data bank based on three command signals of a welding current, the welding voltage and the welding speed to control the welding output. CONSTITUTION:In general, when the welding speed increases, since weld defects such as an undercut, the humping, etc., are liable to take place, a reduction rate of the welding output is changed to improve the welding limit speed. In other words, the data to obtain an optimum output control waveform according to the welding current, voltage and speed are stored in the data bank 10. When a CPU 23 reads the inputted welding current, voltage and the welding speed through a command value receiving circuit 24 from the robot controller 17, it selects the optimum value from among the data bank 10 and inputs these data to a welding output control circuit 9. The output of the welding output control circuit 9 is inputted to a switching element 2 through a pulse width modulator 8 and a driver 7 and the welding output voltage is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an arc welding device for automatic welding used with a welding robot and a welding jig.

2. Description of the Related Art Conventional arc welding machines for automatic welding have a relatively narrow welding speed range of 30 to 80 CPM, and are based on low-speed arc welding machines for semi-automatic welding.

Adjustments that were performed directly by the welding operator, such as adjusting the wire feed rate and welding output, turning the torch switch ON and OFF
F. This is an improved version that allows the torch to be operated through a welding robot or welding jig.

Among these, the adjustment of welding output is the wire feed amount.

This is done to set the arc condition within an appropriate range to prevent arc instability or welding defects due to differences in the distance between torch base materials, welding posture, weld joint shape, etc. It is.

Therefore, even when high-speed welding of 11,000 P or more is performed by automatic welding, the welding output is adjusted within the relatively low speed semi-automatic welding range of 30 to 80 CPM.

Problems to be Solved by the Invention As described above, in the conventional example, the welding output control method for low-speed welding is directly applied to high-speed welding, so welding defects such as undercuts and humping, which are characteristic of high-speed welding, are avoided. There are problems that are likely to occur. This problem contradicts the main purpose of automatic welding, which is to improve welding speed.

The present invention solves the above problems by automatically controlling the welding output to an appropriate value according to the welding speed, and by configuring it so that an appropriate welding output can be obtained even during high-speed welding, which has been conventionally difficult. The purpose is to

Means for Solving the Problems In order to solve the above problems, the arc welding apparatus of the present invention controls welding output by selecting the optimum value from the input welding voltage command signal and welding current -ta. It is equipped with an output control circuit that can perform the following functions.

Effect: Since the above configuration selects the optimal data for determining the output according to the welding speed, it is possible to obtain the optimal welding output control waveform according to the welding speed.

Embodiment One embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is a rectifier that rectifies a three-phase AC power supply voltage. The output terminal of the rectifier 1 is connected to the primary winding of the main transformer 3 via the welding output control element 2, and high frequency voltage is applied to the primary winding of the main transformer 3 by the switching operation of the welding output control element 2. Occur. The high frequency voltage generated in the secondary winding of the main transformer 3 is rectified by a rectifier 4, smoothed by a smoother 5, and supplied between the wire 16 and the base material 16 via the output terminal 6.

22 is a robot body, and a conker 14 is provided at the tip of the arm. 17 is a welding robot control device;
Torch switch command device 18. Welding speed command device 19.
A welding current command device 2oA and a welding voltage command device 21 are provided. A welding speed command signal is output from the welding speed command device 19.

The welding current command signal output from the welding current command device 20 and the welding voltage command signal output from the welding voltage/command device 21 are read into the CPU 23 via the command value receiving circuit 24. Further, the torch switch command signal output from the torch switch command device 18 is read into the CPO 23 via the torch signal receiving circuit 25. 10 is a data bank, which stores data for obtaining an optimal output control waveform according to welding current, voltage, and speed.

When the CPU 23 reads the welding current, voltage, and welding speed from the robot control device 17 through the command value receiving circuit 24, the CPU 23 selects data determined by the welding current distribution, voltage head, and welding speed from the data bank 1o. This data is input to the output control circuit 9, and a welding output control waveform is formed based on this data.

Reference numeral 11 denotes a short-circuit/arc discrimination circuit that detects the voltage between the output terminals 6 to discriminate whether it is a short-circuit state or an arc state. The output of this short circuit arc discrimination circuit 11 is input to the welding output control circuit 9. The output control circuit 9 receives the signal from the short-circuit/arc discrimination circuit 11 and forms optimum output control waveforms for each of the short-circuit and the arc-circuit based on data from the CPU 23. The wire feed motor 13 operates as the wire feed command circuit 12 is driven by the output of the welding output control circuit 9, and feeds the wire 16.

Further, the output of the welding output control circuit 9 causes the pulse width modulation circuit 8. The driver circuits 7 are sequentially driven.

The welding output control element 2 is switched.

In the above configuration, 1. The operation details are as follows.

The welding speed command signal from the welding speed command device 19 of the welding robot control device 17, the welding current command signal from the welding current command device 20, and the welding voltage command signal from the welding voltage command device 21 are sent via the command value receiving circuit 24. Read into CPO23. The CPU 23 selects data determined from the above three command values from the data bank 10, and this data is input to the output control circuit 9. Further, a signal indicating whether the welding output state is a short circuit or an arc state is inputted from the short circuit arc discrimination circuit 11, and an output control waveform is formed based on the above data. The output of the output control circuit is input to the switching element 2 through the pulse width modulation circuit 8 and the driver 7 to control the welding output voltage. Another output control signal from the welding output control circuit 9 is output to the wire feed command circuit 12 to control the wire feed speed.

Here, the command value receiving circuit for welding current, voltage, and speed will be explained. Normally, the output signal from the robot control device 17 is an analog signal, so if the input stage of the welding output control circuit 9 has a digital input configuration, A/D conversion,
When the input of the welding output control circuit 9 has an analog input configuration, it functions to match the manual stage of the welding output control circuit 9 and the output stage of the robot control device 17, such as adjusting the annular opening and the amount of gagging. . When the output signal from the robot control device 17 is a digital signal.

The command value receiving circuit 24 may not be provided. The torch switch signal receiving circuit receives the torch switch signal from the robot.
U operates to convert that timing into a readable signal.

Regarding the welding output control characteristics described above, data is selected to obtain the optimal analog control waveform depending on the welding current, voltage, and speed, but according to our detailed experimental results, short circuits occur when the welding speed is different. Select data that provides a control waveform that increases the welding output after opening, and increase the welding output reduction rate after opening the short circuit. It was found that when the welding speed is high, good welding results can be obtained when data is selected that provides a control waveform that lowers the welding output after the short circuit is opened. Also, when the welding speed is low, select data that provides a control waveform that increases the rate of decrease in welding output after opening a short circuit, and when the welding speed is high, select data that yields a control waveform that reduces the rate of decrease in welding output after opening a short circuit. It has been found that good welding results can be obtained when data is selected.

FIG. 2 shows how the limit speed at which welding can be performed using a welding power source having the control characteristics of the present invention changes depending on the welding output reduction rate after the short circuit is opened.

Generally, as welding speed increases, welding defects characteristic of high-speed welding, such as undercuts and humping, are more likely to occur; however, by changing the welding power reduction rate with the configuration of the present invention, the welding limit speed can be greatly improved. .

In other words, it is possible to greatly improve welding performance by obtaining a welding output control waveform that provides a welding output reduction rate after short-circuit opening that is appropriate for the welding current, voltage, and welding speed, and this is effective in improving welding performance. It turned out to be true.

FIG. 3 shows the relationship between the welding output reduction rate and the amount of spatter generated after short-circuit opening in low-speed welding (500 PM). Note that 1. The wire diameter used is 1.
This is the case of 2■φ, overlap fillet welding. The amount of spatter generated is a major factor in determining the quality of welding in terms of appearance and maintenance of the torch area, but the greater the welding output reduction rate, the less the amount of spatter generated, and the better the welding result.

Next, an example of the configuration of the data bank will be explained.

Signal ↓%v1jv21..., an array corresponding to the welding speed command value is selected in VnO. FIG. 4 specifically shows only the data arrangement when the welding current command value is . When the welding current command value is set, the data is selected. Welding current command value is 1.

When the welding speed command value is vl, data is selected from the data array v1. Data array v1 contains data v11. v12. v13. . . , v19 are stored, and data (for example, vlfi") selected by the welding voltage command value is determined and output.

Welding current command value other than I2. I3. ...t
``m'' also has a table similar to ``work''. As mentioned above, the welding output control waveform is determined by these data.

The example shown in Figure 4 shows a configuration in which individual control conditions are written in a data bank and read out based on input conditions, but it can also be easily realized with a configuration in which control conditions are calculated based on input conditions. can.

Effects of the Invention As described above, the present invention enables appropriate welding output control for each welding speed, thereby providing stable welding results from low to high speeds. Moreover, there is no need for the user to adjust control parameters regarding welding speed.

Setting welding conditions is very easy. in this way.

The present invention has great effects such as increasing welding speed, increasing production efficiency, ensuring welding quality, making the work easier even for workers who are not proficient in welding, and enabling welding automation using welding robots etc. .

[Brief explanation of the drawing]

Fig. 1 is a block circuit diagram of an arc welding machine showing an example of the present invention, Fig. 2 is a characteristic diagram showing the relationship between welding output reduction rate and welding speed limit, and Fig. 3 is a welding output reduction rate and spatter. A characteristic diagram showing the relationship between generation amounts. FIG. 4 is a block diagram of the data bank in FIG. 1. 9... Welding output control circuit, 19... Welding voltage command device, 20... Welding current command device,
21...Welding voltage command device. Name of agent: Patent attorney Toshio Nakao and 1 other graduate 2
Picture Shimocha Sashiki'/e:"On+S) Aoi 3's

Claims (1)

[Claims] In an arc welding device using a consumable electrode, three signals are provided: a welding current command signal, a welding voltage command signal, and a welding speed command signal.
An arc welding device equipped with an output control circuit that controls welding output by selecting an optimal value from data stored in a welding condition data bank based on two command signals.