JPS63252677A - Arc welding equipment - Google Patents

Abstract

PURPOSE:To control the pertinent welding output with respect to the welding speed by calculating the differential voltage between a welding voltage command value based on a welding voltage command signal and the control voltage based on the standard output control data to control the welding output. CONSTITUTION:A CPU 23 selects the feed quantity and the standard output control data from among the data stored in a welding condition data bank 20 based on a welding current command value and a welding speed command value from a robot controller 17. Moreover, on the other hand, the CPU 23 reads the welding voltage command value Vp from the robot controller 17 and calculates the differential voltage control voltage DELTAVs from the welding voltage command value Vp and the control data voltage Vs and the melting output control voltage (Vs+ or -DELTAVs) is determined. These control data are inputted to an output control circuit 9. By this method, the pertinent welding output can be controlled with respect to each welding speed and a stable welded result from the low speed up to the high speed is given.

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.

Conventional technology Conventional arc welding machines for automatic welding have a relatively narrow welding speed range of 30 to 800 PM, and are based on low-speed arc welding machines for semi-automatic welding. This has been improved so that adjustments and operations such as wire feed rate and welding output adjustments, torch switch ON/OFF operations, and torch operations can be performed 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 automatic welding is performed at a high speed of 100 CPM or more, the welding output is adjusted within the relatively low speed semi-automatic welding range of 30 to soCPM.

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 some problems that can easily 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 a problem in the past. It is intended for this purpose.

Means for Solving the Problems In order to solve the above problems, the arc welding machine of the present invention uses data stored in the welding condition data bank based on the input welding current command signal and welding speed command signal. Output control that controls welding output by selecting the wire feed amount and standard output control data from , and calculating the difference voltage between the welding voltage command value based on the welding voltage command signal and the control voltage based on the standard output control data. It is equipped with a circuit.

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

Embodiments Hereinafter, embodiments of the present invention will be described 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 this rectifier 1 is connected to the primary winding of the main transformer 3 via the welding output control element 2, and the switching operation of the welding output control element causes the main transformer 4 to be connected to the primary winding of the main transformer 3.
A high frequency voltage is generated in the primary winding. The high frequency voltage generated in the secondary winding of the main transformer 3 is rectified by a rectifier 4,
The wire is smoothed by the smoother 5 and supplied between the wire 15 and the base material 16 via the output terminal 6.

22 is the robot body, with a torch 14 at the tip of the arm.
is provided. 17 is a welding robot control device, which includes a torch switch command device 18 and a welding speed command device 19.
．． A welding current command device 20 and a welding voltage command device 21 are provided. A welding speed command signal 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 6 and output from the torch switch command device 19 The torch switch command signal sent is read into the CPU 23 via the torch signal receiving circuit 26. Reference numeral 10 denotes 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 a wire determined based on the welding current command value and welding speed command value from the data bank. Select the feed rate and standard output control data, calculate the differential voltage control voltage based on the control voltage based on this standard output control data (hereinafter simply referred to as control data voltage), and the welding voltage command value, and calculate the welding output. The control voltage is calculated and obtained, and the control voltage is input to the output control circuit 9 via the data 1cPU 23 to form a welding output control waveform.

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 control data from the CPU 23. Wire feed motor 1
3, a wire feed command circuit 12 is driven and operated by the output of the welding output control circuit 9, and feeds the wire 15.

Further, the output of the welding output control circuit 9 controls the pulse width modulation circuit 8. The driver circuit 7 is sequentially driven to switch the welding output control element 2.

In the above configuration, 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 2o, and the welding voltage command signal from the welding voltage command device 21 are sent via the command value receiving circuit 24. It is read into the CPU 23. The command value receiving circuit 24 is connected to the robot control device 17.
This is an A/D conversion circuit for converting an analog output signal into a digital signal.The signal from the robot control device 17 is first converted into an analog signal by the A/D conversion circuit, and then sent to the CPU 23. Loaded. If the output signal from the robot control device 17 is a digital signal, it is directly read into the CPU 23. The torch switch signal receiving circuit 25 operates to convert the torch switch signal from the robot into a signal whose timing can be read by the CPU 23.

The CPU 23 selects the wire feed amount and standard output control data from the data stored in the welding condition data bank based on the welding current command value and welding speed command value from the robot control device 17.

On the other hand, the CPU 23 reads the welding voltage command value Vp from the robot control device 17, calculates the differential voltage control voltage ΔVS from the welding voltage command value Vp and the control data voltage vs, and calculates the welding output control voltage (VS±ΔVS ) is determined. This control data is input to the output control circuit 9. The details of this part will be further explained using FIG. 2.

In FIG. 2, numeral 10 indicates the arrangement of data in the data bank. Based on the welding current command signal input to the CPU 23, the welding current 11. I. , . . . Wire feeding amount vG1 corresponding to Eyu. vG2.・・・・・・,vG! 1
is selected. Further, the welding speed command signal input to the CPU 23 determines the welding speed V1. V2.・・・－・・Vn
A data bank corresponding to is selected, and a data array that matches the welding current command value is selected in the data bank corresponding to each speed, and the welding current machiner 11"2'...
Engineering. Standard output control data Ds and fine adjustment control data ΔDs that match are selected. FIG. 2 shows welding speed command values vl, v2. Welding current command value is 11°! 2, but other welding speed command values (v3..., Vn) and other welding current command values (Eng.,...) are shown. .,!n) also show the same arrangement. According to our detailed study results, we were able to secure a control data voltage VB that allows good welding when welding speed command values are set at every 25α/min data bank and welding current command values are set at every 1 to 4 A. Now, if the welding speed command value is vl and the welding current command value is 11, then the wire feed amount vG1. Then, standard output control data D11 and fine adjustment control data ΔD11 are selected, and control data voltage v11. and fine control data voltage Δv, 1
is obtained. When the welding voltage command value based on the welding voltage command signal input to the CPU 23 is vP, the welding output control voltage vc is obtained as follows. First, the difference ΔVSP between the control data voltage v11 and the welding voltage command value Vp=
1v11 to vP1 are calculated.

The differential voltage control voltage ΔVS corresponding to the differential voltage ΔVSP is determined by the product of the differential voltage ΔVSP and the fine adjustment control data voltage Δv11, that is, ΔV3 = ΔVSP X Δv11. Therefore, the welding output control voltage vc based on the welding voltage command value vP is determined by the sum or difference of the control data voltage v11 and the differential voltage control voltage ΔVS, that is, vc=v11±ΔVs. Differential voltage control voltage ΔVS
When the welding voltage command value is larger than the standard output, that is, when vP≧v11, the welding output control voltage VC
becomes vc=v11+ΔVs.

Conversely, when the welding voltage command value is lower than the standard output, that is, when vP<vll>, the welding output control voltage vc
is vc=v11-ΔVS.

The CPU 23 calculates the welding output state voltage and voltage VC.
is output to the control circuit 9. On the other hand, a signal indicating whether the welding output state is a short circuit or an arc state is input from the short circuit arc discrimination circuit 11 to the control circuit 9, and the control data Vc
Based on this, the output control waveforms during arcing and short circuit are formed.

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.

The welding current command signal from the robot as described above.

The welding output control data determined based on the welding speed command signal and the welding voltage command signal is input to the control circuit 9, and the output control waveform suitable for the welding current value, welding voltage value, and welding speed is applied during short circuit and arcing. Compared to the method in which the welding output is controlled simply based on the welding current and welding voltage command values, the welding speed signal is newly applied as a control signal, and by creating an appropriate control waveform that takes the welding speed into consideration. It is possible to obtain excellent results in welding performance. The main issues that have attracted attention regarding welding performance are the welding limit speed and the amount of spatter generated during welding. We will next investigate the control wave shape that can improve the welding limit speed and reduce spatter. the result,
When the welding speed is low, select data that provides a control waveform that increases the welding output after the short circuit is opened, and increase the welding output reduction rate after the short circuit is opened. 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. 3 shows how the limit speed at which welding can be performed using the welding power source having the control characteristics of this embodiment changes depending on the welding output reduction rate after the short circuit is opened. Generally, as the welding speed increases, welding defects characteristic of high-speed welding, such as undercuts and humping, are more likely to occur, but by changing the welding power reduction rate in this example, 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. This proved to be an effective method for improving performance.

FIG. 4 shows the relationship between the welding output reduction rate and the amount of spatter generated after short-circuit opening in low-speed welding (soCPM). Note that this is a case of overlap fillet welding using Co2 welding with a wire diameter of 1.2 mm. 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.

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, it is not necessary for the user to adjust control parameters related to welding speed, and it is very easy to set welding conditions.

As described above, the present invention increases welding speed, improves production efficiency, ensures welding quality, enables easy welding even for workers who are not proficient in welding, and facilitates welding automation using welding robots. is very large.

[Brief explanation of drawings]

FIG. 1 shows an arc welding apparatus and a second embodiment of the present invention.
The figure shows the specific configuration of the data bank of the device, and Figure 3 is a characteristic diagram showing the relationship between welding output reduction rate and welding speed limit.
FIG. 4 is a characteristic diagram showing the relationship between the welding power reduction rate and the amount of spatter generated. 9... Welding output control circuit, 19... Welding speed command device, 20... Welding current command device,
21...Welding voltage command device.

Claims (2)

[Claims] (1) In an arc welding device using a consumable electrode, the wire feed amount is selected from data stored in a welding condition data bank using a welding current command signal, and the wire feed rate is selected from data stored in a welding condition data bank using a welding current command signal and a welding speed command signal. , select standard output control data from the data stored in the welding condition data bank, and select a welding voltage command value V_P based on the welding voltage command signal and a control voltage V_S based on the standard output control data. The welding output control circuit calculates a differential voltage control voltage ΔV_S to obtain a welding output control voltage (V_S±ΔV_S), and performs welding output control according to the value of the welding output control voltage (V_S±ΔV_S). An arc welding device characterized by: (2) The welding condition data bank is the differential voltage control voltage ΔV_
The arc welding apparatus according to claim 1, wherein fine adjustment data for calculating S is stored, and the fine adjustment data is selected by a welding current command signal and a welding speed command signal.