JP3004889B2 - Non-consumable electrode arc welding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-consumable electrode type arc welding machine used for general-purpose TIG welding and plasma arc welding, and more particularly to various settings in these welding machines.

[0002]

2. Description of the Related Art In a power supply device used for a welding machine as described above, a commercial AC power supply is rectified by an input-side rectifier, and the rectified high-frequency power is switched by a power switching element. ,
After a predetermined high-frequency voltage, the voltage is again rectified by the output-side rectifier and supplied to a load including the electrode and the welding work. Also, the output current supplied to the load is detected, and the output current is made constant by performing feedback control for controlling the power switching element based on the detection signal.

When this power supply device is used, as shown in FIG. 5, an electrode is first brought close to a welding work at the time of starting, and a shield gas is supplied between them for a predetermined gas preflow time Tpri. Next, a high voltage is applied between the electrode and the welding work to generate an arc, and an initial current Ii flows between the electrode and the welding work to preheat the welding work. After passing the initial current Ii, in order to prevent the welding work from being weld cracked due to rapid heating,
Perform up-slow to gradually increase the output current. The up throw time Tu for performing the up throw is set in advance.

After the up throw, a base current Ib and a pulse current Ip are applied to the welding load. Pulse current Ip
Is used to increase the depth of penetration and the concentration of the arc, and flows only for the pulse time Tp of the pulse cycle Tf. In addition, when the frequency of the pulse current Ip is low, the penetration depth increases, which is suitable for welding a thick plate. In addition, when the pulse current Ip is set to a high frequency, the concentration of the arc is increased, and the thin plate can be welded. Welding is performed by the pulse current Ip and the base current Ib.

[0005] When the welding is almost completed, a downslope is performed to gradually reduce the current to the crater current Ic in order to prevent the formation of a depression (crater) in the weld pool. Down slope time Td for performing this down slope
Is also predetermined.

After the crater current Ic flows, the current supplied to the load is cut off. After this, the shield gas is also allowed to flow for a short gas after flow time Ta, and then the shield gas is also shut off.

[0007] When welding a tack or a curved portion, spot welding is performed. In this case, a large current spot current is supplied for a short time instead of the base current Ib or the pulse current Ip. Sometimes.

In the above welding machine, the pulse current Ip
And the base current Ib are used for the pulse welding, but a direct current may be continuously supplied instead of the pulse welding.

[0009]

In the above welding machine, the initial current Ii, the pulse current Ip, the base current Ib,
It is necessary to adjust the crater current Ic, and also to adjust the up slope time Tu, the pulse period Tf, the pulse time Tp, and the down slope time Td. When performing spot welding, it is necessary to adjust the spot time Ts in addition to the up slope time Tu and the down slope time Td. Even when a continuous DC current is applied, the pulse current Ip and the base current Ib Instead, the DC current needs to be adjusted.

Therefore, when performing precise welding, output currents such as initial current Ii, pulse current Ip, base current Ib, crater current Ic, up slope time Tu, pulse cycle Tf, pulse time Tp, down slope time T
The adjustment of the time such as d is performed, but the general-purpose arc welding machine has a problem that the adjustment of the output current and the time is very complicated, and the adjustment takes time. Furthermore, since a large number of regulators for each output current and each time are provided on the panel, the adjustment work is troublesome, and the area occupied by the respective regulators on the panel is increased. Had become.

An object of the present invention is to provide a non-consumable electrode type welding machine which simplifies the function of each adjustment and is easy to use.

[0012]

According to the first aspect of the present invention, a current is gradually increased over an up-slope time toward a welding current, and thereafter, a welding current is applied, and the current is gradually increased from the welding current over a down-slope time. In a non-consumable electrode type arc welding machine for reducing the welding current, welding current setting means for setting the welding current, time setting means for setting the down slope time, and according to the down slope time set by the time setting means. First automatic setting means for automatically setting the up slope time.

According to a second aspect of the present invention, in the first aspect, the current at the start of the up slope is a preset initial current, and the setting of the initial current is set by the welding current setting means. It is automatically set by the second automatic setting means according to the welding current.

According to a third aspect of the present invention, in the first or second aspect, the current at the end of the down slope is a predetermined crater current, and the setting of the crater current is performed by the welding current setting means. Is automatically set by the third automatic setting means in accordance with the welding current set by the above.

According to a fourth aspect of the present invention, in the second or the third aspect of the present invention, the shielding gas is supplied from a point of time when the supply of the initial current is started up backward by a preset gas preflow time. The time is set to a fourth value according to the welding current set by the welding current setting means.
Are automatically set by the automatic setting means.

According to a fifth aspect of the present invention, in the second or third aspect, the shield gas flows for a preset gas after-flow time even after the supply of the crater current is stopped, and the setting of the gas after-flow time is reduced. The fifth automatic setting means automatically sets the welding current according to the welding current set by the welding current setting means.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the welding current is a pulse current. In a seventh aspect based on the sixth aspect, the pulse current is generated for each pulse period for a pulse time, and the pulse current is set according to the pulse cycle setting means and the pulse cycle set by the setting means. A sixth automatic setting means for automatically setting the pulse time is provided. In an eighth aspect based on any one of the first to fifth aspects, the welding current is a continuous direct current.

[0018]

According to the first aspect, when the down slope time is set by the time setting means, the up slope time is automatically set by the first automatic setting means accordingly. Generally, the up slope time is correlated with the down slope time. Therefore, the up slope time can be automatically set according to the setting of the down slope time.

According to the second invention, when the welding current is set by the welding current setting means, the initial current is automatically set by the second automatic setting means accordingly. Since the initial current has a correlation with the welding current, the initial current is automatically set according to the setting of the welding current.

According to the third aspect, when the welding current is set by the welding current setting means, the crater current is automatically set by the third automatic setting means accordingly. Since the crater current has a correlation with the welding current, the crater current is automatically set according to the setting of the welding current.

According to the fourth aspect, when the welding current is set by the welding current setting means, the gas preflow time is automatically set by the fourth automatic setting means. Since this gas preflow time also has a correlation with the welding current,
The gas preflow time can be automatically set according to the setting of the welding current.

According to the fifth aspect, when the welding current is set by the welding current setting means, the gas after-flow time is automatically set by the fifth automatic setting means.

According to the sixth invention, a pulse current is used as the welding current, and according to the seventh invention, the pulse current is generated for a fixed pulse time for each fixed pulse period. When the pulse period setting means sets the pulse period, the sixth automatic setting means automatically sets the pulse time accordingly. By adjusting the pulse period, the penetration depth and the arc concentration are adjusted. The pulse time is a value within the pulse cycle, and has a correlation with the pulse cycle. Therefore, the pulse time can be automatically set according to the setting of the pulse period. According to the eighth aspect, the welding current is a continuous DC current.

[0024]

In this embodiment, the present invention is applied to a general-purpose arc welding machine, and has an input terminal 2 to which a commercial AC power is input, as shown in FIG. The commercial AC power supply at the input terminal 2 is rectified by an input-side rectifier 4 and converted into high-frequency AC by an inverter 6 having a built-in power switching element such as an IGBT, MOSFET, or power transistor. The high-frequency alternating current from the inverter 6 is transformed into a predetermined voltage by the high-frequency transformer 8, rectified again by the output rectifier 10, and supplied to the welding load 12 including the electrode and the welding work. Although not shown, the electrodes are provided on a torch, and the torch has a shield gas supply source (not shown).
Gas is supplied from the
6 controls the supply of the shielding gas from the supply source to the torch.

The output current supplied to the load 12 is detected by a current detector 14 provided between the output rectifier 10 and the load 12, and is converted into a digital signal by an A / D converter 16. After that, it is supplied to the microcomputer 18. The A / D converter 16 is also supplied with signals from a welding current setting unit 20, a time setting unit 22, and a frequency setting unit 24, which will be described later. These signals are also converted into digital signals and then supplied to the microcomputer 18. You.

The microcomputer 18 additionally includes a mode changeover switch 2 of each of the setting units 20, 22, and 24.
6, 28 and 30 are connected, and further, a torch switch 32 provided on the torch is connected together with the electrodes of the load 12.

The microcomputer 18 sends a digital signal to the D / A converter 34 in accordance with the digital signal from the A / D converter 16 and the states of the switches 26, 28, 30, and 32 according to a program stored in advance. Supply a control command signal. This digital control command signal is
The signal is converted into an analog command signal by the A converter 34 and supplied to the gas switching device 36 or to an inverter control device 38 for controlling the inverter 6.

The welding current setting unit 20 outputs a welding current, for example, in the case of pulse welding, a pulse current I as shown in FIG.
In the case of DC welding, p is a value for setting a DC current continuously flowing between an up-slow time Tu and a down-slow time Td as shown in FIG. Switching is performed by operating the mode changeover switch 26. In the DC current mode, the value of the spot current for spot welding can be set.

The welding current and the gas preflow time Tpri and the gas afterflow time Ta shown in FIG. 5 need to have a correlation, for example, a substantially proportional relationship as shown in FIG. If the current is set large,
Gas preflow time Tpri and gas afterflow time T
a also needs to be set large. Therefore, when the welding current is set, the microcomputer 18 automatically sets the gas preflow time Tpri and the gas afterflow time Ta proportional to the set welding current.

Similarly, the welding current and the initial current Ii and the crater current Ic shown in FIG. 5 have a correlation, for example, 20 to 30% with respect to the welding current, as shown in FIG.
Is required. Accordingly, when the welding current is set, the microcomputer 18 determines that the initial current Ii and the crater current Ic are proportional to the set welding current.
Set automatically.

In the case of pulse welding, the pulse current Ip
Is supplied while being superimposed on the base current Ib. The base current Ib is determined by the pulse current Ip depending on the thickness of the welding work.
Is often selected from 1/2 to 1/5, and usually is often selected to 1/3. Therefore, when pulse welding is selected by the mode changeover switch 26, the microcomputer 18 automatically sets the base current Ib to the set welding current, that is, 1/3 of the pulse current Ip.

The time setting unit 22 has a down slope time T
This is for setting d and the spot time Ts at the time of spot welding. When setting the downslope time Td, the mode changeover switch 28 is opened, for example, and the time setter 2 is operated as a downslope time setting mode. On the other hand, there is a correlation between the downslope time Td and the upslope time Tu, and for example, as shown in FIG. It is. Therefore, in this embodiment, the microcomputer 1
8, when the down slope time Td is set, 5
The up slope time Tu is automatically set to 0%.

Also, such a down slope time Tu
And the spot time Ts at the time of spot welding does not correspond one-to-one, so the mode changeover switch 28 is closed, for example, and the spot time Ts is set as the spot time Ts setting mode. In this case, the mode switch 28
The down-slope time Td set in a state where is opened is effective.

The frequency setting unit 24 is for setting the frequency (1 / Tf) of the pulse current Ip at the time of pulse welding. The frequency of the pulse current Ip is set to a high frequency when the penetration depth is increased, and to a low frequency when the thin plate is welded by increasing the arc concentration. Since the setting range is too wide to set from a high frequency to a low frequency by one frequency setting unit 24, the frequency range is switched between a high frequency and a low frequency by the changeover switch 30.

The pulse time Tp of the pulse current Ip is generally set to 30 to 50% of the period Tf of the pulse current Ip, and is generally set to 50% for a general-purpose welding machine. Then, the microcomputer 18 automatically sets the pulse time Tp of the pulse current to 50% of the cycle Tf of the pulse current Ip.

As described above, in this embodiment, each setting unit 2
0, 22, 24, and the states of the switches 26, 28, and 30, the gas preflow time Tpri, the gas afterflow time Ta, the initial current Ii, the crater current Ic, the base current Ib, and the pulse time Tp of the pulse current Ip. Are automatically set, so you can easily set up,
The number of setting devices that must be provided can also be reduced. Further, by using the switches 26, 28, and 30,
Since one setting device can be used as a plurality of setting devices, the number of setting devices can be further reduced.

In the arc welding machine configured as described above,
When the torch switch 32 is turned on, a gas supply start command is supplied to the gas opening / closing device 36 via the D / A converter 34 from the microcomputer 18 which has detected the torch switch 32, and the shielding gas is injected from the torch toward the workpiece base material. You.
The microcomputer 18 starts timing at the same time as the injection, and after the elapse of the gas preflow time Tpri from the start of the injection, instructs the inverter control device 38 via the D / A converter 34 to start the inverter 6 and performs welding. A high voltage is applied between the electrode of the load 12 and the welding work to start an arc, thereby causing the initial current Ii to flow through the welding load 12.
The microcomputer 18 automatically sets the gas preflow time Tpri and the initial current Ii according to the value of the welding current (in this case, the pulse current Ip) set by the welding current setting device 20.

When the torch switch 32 is turned off in the state where the initial current Ii is flowing in this way, the microcomputer 18 that detects this turns the upslope to the inverter control device 38 via the D / A converter 34. Supply start command signal. In response to this, the inverter control device 38 gradually increases the output current supplied to the welding load 12 and controls the inverter 6 such that the output current becomes the pulse current Ip after the elapse of the up slope time Tu. This up slope time Tu is calculated by the time setting device 2
The microcomputer 18 automatically sets the downslope time Td according to the setting of the downslope time Td. The current supplied to the welding load 12 during the up slope time Tu is also a pulse current, as is clear from FIG.

After the elapse of the upslope time Tu, the microcomputer 18 supplies a welding control command to the inverter control device 38 via the D / A converter 34, and the inverter control device 38 responds accordingly to the output current. Becomes the pulse current Ip set by the welding current setting device 20,
The pulse cycle Tf becomes the cycle set by the frequency setting device 24, the pulse time Tp becomes a value automatically set by the microcomputer 18 according to the setting of the pulse cycle Tf, and the base current Ib becomes 1/3 of the pulse current Ip. The inverter 6 is controlled so that Note that this control is performed by constant current control using an output current detection value from the current detector 14. Such control is continued while welding is being performed.

When the welding is completed, the torch switch 32 is turned on. The microcomputer 18 that has detected this supplies a down slope command to the inverter control device 38 via the D / A converter 34. In response to this, the inverter control device 38 gradually decreases the output current, and reduces the output current to the crater current Ic when the down slope time Tu elapses. This down slope time Tu
Is set by the time setting unit 22.

When the torch switch 24 is turned off while the crater current Ic is flowing as the output current in this way, the microcomputer 18 detects this, and
The microcomputer 18 supplies a stop command to the inverter control device 38 via the D / A converter 34. In response to this, the inverter control device 38 sets the crater current Ic
The inverter 6 is controlled so as to shut off. At the same time, the microcomputer 18 waits for the afterflow time Ta to elapse, and after the elapse of the afterflow time Ta,
A command to stop the supply of the shielding gas is issued to the gas switching device 36 via the / A converter 34. Thus, the supply of the shielding gas is stopped.

In the above embodiment, the initial current and the crater current are set. However, for example, in the case of performing temporary welding, it is not necessary to supply the initial current, so that these may be removed. Further, when the reliability of the finished weld is not so required, it is not necessary to supply a crater current, so that it may be removed. Although the description of the above embodiment is for the case of pulse welding, various settings are also automatically performed for DC welding and spot welding, as in the above description. In the case of DC welding, the current supplied to the welding load 12 during welding is a DC current as shown in FIG. 6, and the up slope time Tu and the down slope time T
During the period d, the current supplied to the welding load 12 is such that the pulse current does not continuously increase but the DC current continuously increases.

[0043]

As described above, according to the first to eighth aspects of the present invention, the welding current setting means, the time setting means, the pulse cycle setting means, etc. are operated to set the welding current, down slope time, When the pulse period and the like are set, the set values related to these set values are automatically set. Therefore, as described above, the initial current and the crater current are automatically set according to the setting of the welding current, and the up slope time is automatically set according to the setting of the down slope time,
Since the pulse time can be automatically set according to the setting of the pulse cycle, the number of adjustment points is reduced, the setting work is simplified, and the number of setting means that must be operated can be reduced. Since the number of setting means provided on the surface is also reduced, the space can be saved and the welding machine can be downsized.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of a non-consumable electrode type arc welding machine according to the present invention.

FIG. 2 is a diagram showing a relationship among a welding current, an initial current, a crater current, a gas preflow time, and a gas afterflow time in the example.

FIG. 3 is a diagram showing a relationship between a down slope time and an up slope time in the embodiment.

FIG. 4 is a diagram showing a relationship between a pulse current and a base current in the embodiment.

FIG. 5 is an explanatory diagram of an operation in the case of pulse welding in the embodiment.

FIG. 6 is an operation explanatory diagram in the case of DC welding in the embodiment.

[Explanation of symbols]

Reference Signs List 18 microcomputer (first to third setting means) 20 welding current setting device (welding current setting device) 22 time setting device (time setting device) 24 frequency setting device (pulse cycle setting device) Tpri gas preflow time Ta gas Afterflow time Tu Up slope time Td Down slope time Tf Pulse period Tp pulse time Ii Initial current Ic Crater current Ib Base current Ip Pulse current

──────────────────────────────────────────────────続 き Continuing on the front page (72) Atsushi Kinoshita 2-14-3 Awaji, Higashi-Yodogawa-ku, Osaka-shi, Osaka Inside Sansha Electric Manufacturing Co., Ltd. (72) Haruo Moriguchi 2-Awaji, Higashi-Yodogawa-ku, Osaka-shi, Osaka No. 14-3 Sansha Electric Works Co., Ltd. (72) Inventor Toru Arai 2-14-3 Awaji, Higashiyodogawa-ku, Osaka City, Osaka Prefecture Inside Sansha Electric Works Co., Ltd. (72) Inventor Masao Katooka Higashiyodogawa, Osaka City, Osaka Prefecture 2-14-3 Awaji-ku, Sansha Electric Works, Ltd. (56) References JP-A-63-201165 (JP, A) JP-A-1-181970 (JP, A) JP-A-2-104473 (JP) JP-A-7-204849 (JP, A) JP-A-64-22472 (JP, A) JP-A-1-113174 (JP, A) JP-A-63-123569 (JP, A) 64-66070 (JP A) (58) investigated the field (Int.Cl. ^7, DB name) B23K 9/10 B23K 9/073 B23K 9/09 B23K 9/167 B23K 10/00

Claims (8)

(57) [Claims] 1. A non-consumable electrode type arc welding machine that gradually increases current over an upslope time toward a welding current, then applies a welding current, and gradually reduces the current from the welding current over a downslope time. A welding current setting means for setting the welding current; a time setting means for setting the down slope time ; and 30 to 30 of the down slope time set by the time setting means.
Non-consumable electrode type arc welding machine, comprising: first automatic setting means for automatically setting the up slope time to 50% . 2. The non-consumable electrode type arc welding machine according to claim 1, wherein the current at the start of the up slope is:
It is a preset initial current, and the setting of the initial current is
The welding current set by the welding current setting means
20. A non-consumable electrode type arc welding machine characterized in that it is automatically set to 20 to 30% by a second automatic setting means. 3. The non-consumable electrode type arc welding machine according to claim 1, wherein the current at the end of the down slope is a preset crater current, and the crater current is the welding current setting means. A non-consumable electrode-type arc welding machine, wherein the welding current is set to 20 to 30% of the welding current set by the third automatic setting means. 4. The non-consumable electrode type arc welding machine according to claim 2, wherein the shield gas is supplied from a point when the supply of the initial current is started and the gas is reversely moved by a preset gas preflow time. The preflow time is proportional to the welding current set by the welding current setting means.
Non-consumable electrode arc welding machine characterized in that it is automatically set by the to fourth automatic setting means. 5. A method according to claim 2 or 3 non-consumable electrode arc welding machine described in the said shielding gas even after the supply stop of the crater current to flow for a preset gas after-flow time, said gas after-flow time the ratio in the welding current set by the welding current setting unit
For example , the non-consumable electrode type arc welding machine is automatically set by a fifth automatic setting means. 6. The non-consumable electrode type arc welding machine according to claim 1, wherein the welding current is a pulse current. 7. The non-consumable electrode type arc welding machine according to claim 6, wherein the pulse current is generated for each pulse period for a pulse time, and is set by the pulse period setting means and the setting means. 30 or more of the pulse period
A non-consumable electrode-type arc welding machine, comprising: sixth automatic setting means for automatically setting the pulse time to 50% . 8. The non-consumable electrode arc welding machine according to claim 1, wherein the welding current is a continuous DC current.