JPH04367371A - Mig arc welding controller - Google Patents

Abstract

PURPOSE:To easily and accurately set an electric current and the voltage and to improve the welding quality by providing a circuit to output the proper wire feed rate based on an average current set signal, an arc voltage set signal and a wire diameter selection signal. CONSTITUTION:A wire diameter selection circuit WA selects a wire diameter and outputs a wire diameter selection signal Wa. A wire material selection circuit WB selects as to whether a wire is hard or soft and outputs a wire material selection signal Wb. A proper wire feed rate signal output circuit WG inputs an average current set signal Im, an arc voltage set signal Vs1, the wire diameter selection signal Wa and the wire material selection signal Wb. A predetermined proper wire feed rate signal Wg is outputted from these relations. Consequently, an average value of a welding current and an average value of the arc voltage are set and the proper wire feed rate can be automatically obtained.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a current and voltage setting control device for aluminum MIG welding, and its purpose is to make settings easy and accurate and to improve welding quality. .

0002

[Prior Art] Fig. 1 is a diagram showing the relationship between the melting characteristics of an aluminum MIG arc and the droplet transfer form using an aluminum A5183 consumable electrode (hereinafter referred to as wire) with a diameter of 1.6 [mm]. . In the same figure, the horizontal axis Ia [A]
is the welding current, the vertical axis is the arc voltage Va [V], Vf1 to Vf5 are the wire feeding speeds, and L is the apparent arc length [
mm], and the numbers in the figure indicate the apparent arc length.

In general, in MIG welding, the transfer state of droplets from the wire tip depends on the difficulty of the welding operation (arc stability, generation of spatter) and the quality of the welding result (undercut, blowhole, overlap, fusion). defects, etc.), and it is necessary to select appropriate conditions depending on the purpose of welding. In normal aluminum welding, a current value equal to or greater than a critical current value Ic is used as the welding current value Ia. In this case, in the spray arc region shown in [B] in Figure 1, where the apparent arc length (hereinafter referred to as arc length) is large, it is difficult to aim the electrode because the arc length is too long. When welding in a difficult position such as standing up, a large amount of current is required to obtain the same amount of welding (wire melting amount), so the amount of melting on the base metal side becomes excessive and there is a risk of molten metal dripping. There is.

On the other hand, in the short arc region shown in [D] in FIG. 1, where the arc length is extremely short, there are problems such as instability of the arc, generation of spatter, and insufficient melting of the base material. For this reason, the optimal welding condition range is the area where micro short circuits occur (hereinafter referred to as the meso spray arc area) as shown in [C] in the shaded area in Figure 1 at the intermediate arc length, regardless of the current value.
limited to.

In such a meso spray arc region [C], as shown in FIG. 1, the welding current varies greatly depending on the set voltage even if the wire feeding speed is constant.

FIG. 2 shows wire feeding speeds Vf6 to Vf
8 is a diagram showing changes in bead shape and penetration when changing arc voltage value Va (set voltage value). As shown in the figure, in the meso spray arc region [C], changes in the welding current value Ia, for example, B1 to B3 on the dotted line EE', are better than changes in the arc voltage value Va, for example, on the dotted line FF'. It has a greater influence on the bead shape than B4, B2 and B5.

The welding conditions shown in the figure are as follows. Using aluminum A5183 wire with a diameter of 1.6 [mm], plate thickness 16 [mm] aluminum A5058
MI material was placed on a flat plate at a welding speed of 30 [cm/min].
G-welded.

Similar to FIG. 1, FIG. 3 shows a diameter of 1.2 mm.
] shows the melting characteristics of aluminum A5183 wire. As shown in the figure, the set values of the wire feeding speed Vf and the arc voltage are adjusted to a point B10 in FIG. 3 where the welding current is 205 [A] and the arc voltage is 22.5 [V]. In this state, as described above, a case will be considered in which the arc length L is changed by adjusting the arc voltage setting value while reducing the influence on the bead shape and penetration shape. for example,
Keep the wire feeding speed Vf=12.4 [m/min] constant, and set the arc voltage to 24.5 [V].
When raised to , the operating point moves to point B11 in Figure 3,
The welding current value changes to 215 [A]. For this reason, the weld bead changes greatly from the state at point B10.

Therefore, in the conventional control method,
While repeating the adjustment of both the wire feeding speed Vf and the arc voltage setting value Va, the operating point of point B12, that is, the wire feeding speed Vf = 11.9 [m /min]
], it is necessary to adjust the arc voltage set value to 24.5 [V].

FIG. 4 is a block diagram of an apparatus for implementing a conventional MIG welding control method. In the same figure, the consumable electrode 1 is connected to the welding output control circuit PS using the commercial power supply AC as input.
An arc 3 is generated by supplying an output between the power supply tip 4 and the workpiece 2. The consumable electrode 1 is the wire feed motor W
It is supplied from a wire feed roller WR rotated by M. The wire feeding speed control circuit WC is an average current setting circuit I.
A wire feed speed detection circuit W that detects the average current setting signal Im set to M and the rotation speed of the wire feed motor WM.
A wire feed speed comparison circuit (hereinafter referred to as the first comparison circuit) that compares the feed speed detection signal Wd of D. With the wire feed speed control signal Cm1 of CM1 as input, wire feed speed control is performed on the wire feed motor WM. A signal Wc is output. The arc voltage setting circuit VS1 is a circuit for setting an arc voltage, and outputs an arc voltage setting signal Vs1. Second
The comparator circuit CM2 inputs the arc voltage setting signal Vs1 and the arc voltage detection signal Vd of the arc voltage detection circuit VD, and outputs the difference between them, the arc voltage control signal Cm2. The pulse current value setting circuit IP1 outputs a pulse current value setting signal Ip1. Pulse frequency signal generation circuit VF
outputs a pulse frequency control signal Vf in response to the arc voltage control signal Cm2. The pulse width frequency control signal generation circuit DF generates a pulse width frequency control signal D consisting of a pulse width setting signal Tp1 and a pulse frequency control signal Vf.
Output f. The pulse base current switching circuit SW5 has a pulse current value setting signal Ip1 and a base current setting signal Ib.
1 and is switched by the pulse width frequency control signal Df to output the pulse control signal Pf1 and input it to the welding output control circuit PS. ID is a welding current detection circuit that outputs a welding current detection signal Id, and CM3 is a third comparison circuit that receives this welding current detection signal Id and the aforementioned pulse control signal Pf1 as input and outputs a welding current control signal Cm3. be.

The consumable electrode 1 receives a wire feeding speed control signal W.
It is fed at a substantially constant speed predetermined by c. On the other hand, regarding output control, the arc voltage detection signal Vd and the arc voltage setting signal Vs1 are compared and amplified in the second comparison circuit CM2, and the difference between them is the arc voltage control signal Cm2.
is input to a pulse frequency signal generation circuit VF and converted into a pulse frequency control signal Vf. This signal Vf and the pulse width setting signal Tp1 are connected to a pulse width frequency control signal generation circuit DF consisting of a monostable multivibrator circuit.
A width frequency control signal Df having a pulse width Tp1 and a pulse frequency f is output. This signal Df determines the pulse current setting value Ip1 and the base current value setting value I.
b1 is switched.

[0030]

[Problems to be Solved by the Invention] As described above, in the conventional setting control method for the wire feeding speed Vf and the arc voltage value Va, each time the arc length L is finely adjusted, the wire feeding speed Vf
It is necessary to repeatedly adjust the settings of both f and the arc voltage value Va, which is time consuming, and there is a problem that these settings become inaccurate.

[0032]

[Means for Solving the Problems] A MIG arc welding control device comprising a wire average current setting circuit IM that outputs an average current setting signal Im and an arc voltage setting circuit VS1 that outputs an arc voltage setting signal Vs1. A MIG arc welding control device comprising a current setting signal Im, an appropriate wire feeding speed output circuit WG that outputs a predetermined appropriate wire feeding speed signal Wg from the arc voltage setting signal Vs1 and the wire diameter selection signal Wa. be.

[0040]

[Example] Hereinafter, the control device of the present invention will be explained using the block diagram shown in FIG. 5 and the appropriate wire feeding speed signal output circuit W shown in FIG.
This will be explained with reference to a diagram illustrating the function of G, a unified adjustment data table for outputting an appropriate wire feeding speed signal in FIG. 7, and a flowchart of the operation procedure in FIG.

(Explanation of FIG. 5) FIG. 5 is a block diagram of a first embodiment of the MIG arc welding control device of the present invention, which is capable of performing pulse welding. In the figure, description of circuits having the same functions as those in FIG. 4 will be omitted. In the same figure, WA
is a wire diameter selection circuit that selects a wire diameter and outputs a wire diameter selection signal Wa; WB selects a wire material, for example, soft or hard, and outputs a wire material selection signal Wb.
The WG is a wire material selection circuit that outputs an average current setting signal Im, an arc voltage setting signal Vs1, a wire diameter selection signal Wa, and a wire material selection signal Wb, and selects a predetermined appropriate value based on these relationships. This is an appropriate wire feeding speed signal output circuit that outputs a wire feeding speed signal Wg.

(Explanation of FIG. 6) FIG. 6 is a diagram for explaining the function of the appropriate wire feeding speed signal output circuit WG in the block diagram of FIG. It inputs the signal Vs1, the signal Wa, and the signal Wb, and outputs the appropriate wire feeding speed signal Wg. In the same figure, MPU, RAM, ROM, I/O port,
It consists of an A/D conversion circuit and a D/A conversion circuit. An average current setting signal Im and an arc voltage setting signal Vs1 are input from the A/D conversion circuit and a digital signal is output. The ROM reads the digital signals Im and Vs1 from the A/D conversion circuit, the wire diameter selection signal Wa, and the wire material selection signal Wb from the I/O port, and reads the signals shown in FIGS. Search and read out the setting value of the appropriate wire feeding speed from the data table shown in B) and output it to the I/O port. The D/A conversion circuit converts the appropriate wire feeding speed signal Wg input from the I/O port into an analog signal and outputs the analog signal.

(Explanation of FIG. 7) FIG. 7A shows modes depending on each combination of wire diameter, for example, 1.2 [mm] and 1.6 [mm] and wire material, for example, soft and hard. This column shows the relationship from mode 1 to mode 4. For each mode, for example, in mode 2 when the wire diameter is 1.2 [mm] and the wire is hard, the average When the current setting signal Im and the arc voltage setting signal Vs1 are set, the set value of the appropriate wire feeding speed signal Wg is predetermined in a unified adjustment data table, and is stored in the ROM.

The data table in FIG. 3B includes, for example, the welding current value Ia=Ia at point B10 in FIG.
Appropriate wire feeding speed Vf = 12.4 [m /mi when the arc voltage value Va = 22.5 [V] at 205 [A]
n ], and the same welding current value I at point B20
When a=205[A], arc voltage value Va=24.5[V]
Appropriate wire feeding speed Vf when changed to 11.9 [
m /min ], the relationship between each setting value Im, Vs1, and Wg is determined in advance.

(Description of FIG. 8) FIG. 8 is a flowchart of the operating procedure of the diagram for explaining the function of the appropriate wire feeding speed signal output circuit WG of FIG. 6. The procedure in FIG. 8 is as follows. F2 is the wire diameter Wa, for example 1.2 [mm]
and the wire material Wb, for example, hard, is read from the I/O port. In F3, the combination of the read wire diameter Wa and wire material Wb is determined, and a unified adjustment data table suitable for this combination, that is, the mode, for example, mode 2, is selected. F4 reads each set value of the average current setting signal Im and the arc voltage setting signal Vs1 through the A/D conversion circuit. F5 is the ROM of the mode selected above.
From the data table, a set value Wg of the appropriate wire feeding speed signal Wg corresponding to the set values of the average welding current Im and the arc voltage setting signal Vs1 is selected. F6 outputs the selected appropriate wire feeding speed signal Wg from the D/A conversion circuit.

(Explanation of FIG. 9) FIG. 9 is a block diagram of a second embodiment of the MIG arc welding control device of the present invention, which is a control device without pulses. In the same figure, from the block diagram of FIG. 5, each circuit VF, TP necessary for pulse control
1. Excluding DF, IP1, IB1, SW5, ID and CM3, and excluding pulse control operation, Figures 5 to 8
Since the operation is the same as that of , the explanation will be omitted.

In each of the embodiments shown in FIGS. 5 to 9, the case where the wire material selection circuit WB exists has been described, but the wire material selection circuit WB is the same and does not require switching.
In the IG arc welding control device, the wire material selection circuit WB can be omitted. In addition, if you want to fine-tune the appropriate wire feeding speed depending on shielding gas components, welding posture, etc., add a shielding gas component selection circuit and welding posture selection circuit in the same way as the wire diameter selection circuit and wire material selection circuit. Alternatively, a fine adjustment circuit can be added.

[0065]

[Effects of the Invention] As described above, according to the MIG welding control device of the present invention, the average value Ia of the welding current and the average value Va of the arc voltage are set to automatically control the appropriate wire feeding speed. In particular, when it is desired to change only the average value Va of the arc voltage while maintaining the average value Ia of the welding current at a constant value, the conventional wire feeding speed setting circuit and arc voltage setting circuit can be used. Since it is not necessary to repeatedly make fine adjustments to the wire feeding speed to approximate the appropriate wire feeding speed, the setting is easy and accurate settings can be obtained with a single setting. Further, according to the control device of the present invention, the average value Ia of the welding current and the average value Va of the arc voltage can be set independently. The average value of the arc voltage that determines the (apparent) arc length L can be set while the average value Ia of the current is maintained at a constant value.

[Brief explanation of drawings]

[Figure 1] Figure 1 shows aluminum A with a diameter of 1.6 [mm].
FIG. 3 is a diagram showing the relationship between the melting characteristics of an aluminum MIG arc using No. 5183 wire and the droplet transfer form.

[Figure 2] Figure 2 shows that the wire feeding speed is Vf6 to Vf8.
FIG. 3 is a diagram showing changes in bead shape and penetration when changing the arc voltage value Va.

[Figure 3] Figure 3 shows aluminum A with a diameter of 1.2 [mm].
FIG. 3 is a diagram showing the melting characteristics of an aluminum MIG arc using No. 5183 wire.

FIG. 4 is a block diagram of an apparatus implementing a conventional MIG welding control method.

FIG. 5 is a block diagram of a first embodiment of the MIG arc welding control device of the present invention.

6 is a diagram illustrating the functions of the appropriate wire feeding speed signal output circuit WG in the block diagram of FIG. 5. FIG.

FIG. 7A shows the diameter of the wire, for example 1.
2 [mm] and 1.6 [mm] and the wire material, for example,
It is a figure which shows the relationship between modes by each combination of soft and hard, from mode 1 to mode 4 in this example. The same figure (B
) for each mode, for example, the wire diameter 1.2 [
mm] and in mode 2 for hard wire, when the average current setting signal Im and the arc voltage setting signal Vs1 are set, the setting value of the appropriate wire feeding speed signal Wg is set in a predetermined unified adjustment data table. be.

FIG. 8 is a flowchart of the operating procedure of the diagram for explaining the function of the appropriate wire feeding speed signal output circuit WG of FIG. 6;

FIG. 9 is a block diagram of a second embodiment of the MIG arc welding control device of the present invention.

[Explanation of symbols]

1 Consumable electrode 2 Workpiece 3 Arc 4 Power supply tip f Pulse frequency L Apparent arc length Ia Welding current Ib1 Base current setting signal Ic Critical current value Id Welding current detection signal Im Average current setting signal Ip1 Pulse current value setting signal VS1 Arc Voltage setting circuit IP1 Pulse current value setting circuit IM Wire average current setting circuit Wa Wire diameter selection signal Wb Wire material selection signal Wc Wire feeding speed control signal Wd Feeding speed detection signal Wg Appropriate wire feeding speed signal WA Wire diameter selection circuit WB Wire material selection circuit WC Wire feeding speed control circuit WD Wire feeding speed detection circuit WG Appropriate wire feeding speed signal output circuit WM
Wire feeding motor WR Wire feeding roller CM1 Wire feeding speed comparison circuit (first comparison circuit) C
M2 Second comparison circuit CM3 Third comparison circuit Cm1 Wire feeding speed control signal Cm2 Arc voltage control signal Cm3 Welding current control signal Va Arc voltage Vd Arc voltage detection signal Vf1 to 8 Wire feeding speed Vf Pulse frequency control signal Vs1
Arc voltage setting signal Df Pulse width frequency control signal Pf1
Pulse control signal VD Arc voltage detection circuit VF Pulse frequency signal generation circuit DF
Pulse width frequency control signal generation circuit ID
Welding current detection circuit Tp1 Pulse width setting signal SW5 Pulse base current switching circuit AC
Commercial power supply PS Welding output control circuit

Claims (1)

[Claims] [Claim 1] A wire average current setting circuit IM that outputs an average current setting signal Im and an arc voltage setting signal Vs1.
MIG equipped with an arc voltage setting circuit VS1 that outputs
In the arc welding control device, the average current setting signal I
m, and an appropriate wire feeding speed output circuit WG that outputs a predetermined appropriate wire feeding speed signal Wg from the arc voltage setting signal Vs1 and the wire diameter selection signal Wa.
IG arc welding control device.