JP5058678B2 - Non-consumable electrode arc welding power supply - Google Patents

Description

  The present invention relates to a non-consumable electrode arc welding power source that can easily set an appropriate welding current according to various welding conditions.

  Non-consumable electrode arc welding methods include TIG welding and plasma arc welding. Hereinafter, the case of the TIG welding method will be described as an example, but the same applies to the case of the plasma arc welding method.

  FIG. 8 is a typical output current waveform diagram of TIG welding. FIG. 4A shows the shield gas discharge signal Gf, and FIG. 4B shows the output current Io. Hereinafter, a description will be given with reference to FIG.

  When the torch switch is turned on and a start signal is input to the welding power source, as shown in FIG. 5A, the discharge of the shield gas from the nozzle at the tip of the welding torch starts. As shown in FIG. 6A, when the preflow period Tp elapses, the initial current Is is supplied as shown in FIG. When the torch switch is turned off, the output current Io increases from the initial current Is to the welding current Iw during the upslope period Tu, and then the welding current Iw is energized. Here, when the torch switch is turned on again, the output current Io decreases from the welding current Iw to the crater current Ic during the downslope period Td, and thereafter the crater current Ic is energized. Here, when the torch switch is turned off again, energization of the crater current Ic ends. However, as shown in FIG. 5A, the release of the shield gas continues during the afterflow period Ta.

  When welding is performed, the welding operator selects the welding current Iw, the initial current Is, the crater current Ic, the upslope period Tu, according to the welding conditions such as the joint conditions, the material of the workpiece, the plate thickness, and the like. It is necessary to set the down slope period Td, the preflow period Tp, and the afterflow period Ta (hereinafter referred to as parameters) to appropriate values. Setting many of these parameters to appropriate values according to various welding conditions requires many years of experience and troublesome work. In order to cope with this problem, a conventional technique has been proposed in which, if the welding current Iw is set, other parameters are automatically set according to a predetermined relationship with the welding current Iw (for example, Patent Document 1). 2).

Japanese Patent No. 3004889 JP 2006-26663 A

  In the prior art, if the welding current Iw is set, other parameters are automatically set, so that the complexity of the setting is improved. However, the welding current Iw needs to be set to an appropriate value according to the joint conditions, the material of the workpiece and the plate thickness, and this requires years of experience.

  Accordingly, an object of the present invention is to provide a non-consumable electrode arc welding power source capable of automatically setting an appropriate welding current in accordance with the joint shape, the material of the workpiece and the plate thickness.

In order to solve the above-described problem, the first invention is a non-consumable electrode arc welding power source for energizing a welding current set by a welding current setting signal.
A joint setting means for outputting a joint setting signal for setting joint conditions;
Material setting means for outputting a material setting signal for setting the material of the workpiece,
A plate thickness setting means for outputting a plate thickness setting signal for setting the plate thickness of the workpiece,
With the joint setting signal, the material setting signal, and the plate thickness setting signal as inputs, a welding current setting unit that outputs the welding current setting signal according to a predetermined welding current calculation function;
Electrode diameter setting means for outputting an electrode diameter setting signal for setting the diameter of the electrode;
An upper limit current setting unit that outputs an upper limit current setting signal according to the electrode diameter setting signal;
Comparing the upper limit current setting signal and the welding current setting signal, when the value of the welding current setting signal is large, a comparison unit that outputs an alarm signal;
An alarm means for issuing an alarm using the alarm signal as an input;
A non-consumable electrode arc welding power source.

  According to a second aspect of the present invention, the welding current calculation function is a predetermined function that calculates the welding current setting signal by inputting the plate thickness setting signal for every combination condition of the joint setting signal and the material setting signal. The non-consumable electrode arc welding power source according to the first invention, characterized in that it is a group.

  According to a third aspect of the present invention, the welding current calculation function calculates in advance the welding current setting signal by inputting the material setting signal and the plate thickness setting signal for every joint condition set by the joint setting signal. The non-consumable electrode arc welding power source according to the first aspect of the invention, characterized in that it is a defined function group.

5th invention, the output prohibition part which prohibits the output of a welding power source by using the said warning signal as an input,
The non-consumable electrode arc welding power source according to any one of the first to third inventions .

According to the present invention, an appropriate welding current Iw is calculated by a predetermined welding current calculation function and automatically set only by selecting a joint condition, a material to be welded, and a plate thickness. For this reason, many years of experience and troublesome labor are not required for setting the welding current Iw.
Furthermore, an alarm can be issued when the value of the welding current setting signal that is automatically set exceeds the upper limit current value for the electrode diameter. For this reason, it is possible to prevent the electrode from being consumed and the welding quality from being deteriorated.

  Furthermore, since the number of function groups can be reduced by configuring the welding current calculation function as in the third aspect of the invention, it is possible to reduce the time and effort for customizing the function and to add the function group to the welding power source. The storage capacity for storing can also be reduced.

According to the fourth aspect of the invention, in addition to the effects described above, the output of the welding power source can be prohibited when the value of the welding current setting signal that is automatically set exceeds the upper limit current value with respect to the electrode diameter. For this reason, it is possible to prevent the electrode from being consumed and the welding quality from being deteriorated.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram of a non-consumable electrode arc welding power source according to an embodiment of the present invention. The power supply main circuit PM receives a commercial power supply such as a three-phase 200 V input, performs output control such as inverter control and thyristor phase control according to a current error amplification signal Ei described later, and outputs an output current Io. An arc 3 is generated between the non-consumable electrode 1 such as tungsten mounted on the welding torch 4 and the workpiece 2, and an output current Io is conducted through the arc 3. There is a case where welding is performed while adding a filler wire in the arc 3.

  The current detection circuit ID detects the output current Io and outputs a current detection signal Id. The joint setting circuit JR includes a selection switch provided on the front panel of the welding power source, and outputs a joint setting signal Jr corresponding to the selected joint condition. For example, the value of the joint setting signal Jr is 1 when the joint shape is a butt, 2 when the fillet is T-shaped, and 3 when the fillet is overlapped. The material setting circuit MR includes a selection switch provided on the front panel of the welding power source. When the material of the workpiece is selected, a material setting signal Mr corresponding thereto is output. For example, the value of the material setting signal Mr is set to 1 when the material is stainless steel and to 2 when the material is steel. The plate thickness setting circuit TR includes a selection switch provided on the front panel of the welding power source, and outputs a plate thickness setting signal Tr corresponding to the selected plate thickness (mm). The value of the plate thickness setting signal Tr is the plate thickness (mm).

  The welding current setting circuit IWR receives the joint setting signal Jr, the material setting signal Mr, and the plate thickness setting signal Tr as inputs, and sets a preset welding current calculation function Iw = f ( Jr, Mr, Tr) calculates an appropriate welding current Iw, and outputs a corresponding welding current setting signal Iwr.

  The torch switch TS is provided in the hand portion of the welding torch 4 and outputs a torch switch signal corresponding to on / off. The current control setting circuit ICR receives the welding current setting signal Iwr and the torch switch signal Ts as input, and outputs an output current for energizing the output current Io described above with reference to FIG. 8 corresponding to on / off of the torch switch signal Ts. A setting signal Ir is output. The initial current Is, crater current Ic, up-slope period Tu, and down-slope period Td are automatically set by the current control setting circuit ICR according to a predetermined function with respect to the input welding current setting signal Iwr. This will be described in detail with reference to FIG.

  The current error amplification circuit EI amplifies an error between the output current setting signal Ir and the current detection signal Id, and outputs a current error amplification signal Ei. The output current Io described above with reference to FIG. In the figure, the block relating to the shield gas discharge control is omitted.

  FIG. 2 is a configuration diagram of a welding current calculation function built in the welding current setting circuit IWR described above. Hereinafter, a description will be given with reference to FIG.

When the joint setting signal Jr = 1 (butting) and the material setting signal Mr = 1 (stainless steel), the function f11 (Tr) is selected and the value of the plate thickness setting signal Tr (mm) is set. A welding current Iw is calculated as an input. Similarly, the function f12 (Tr) is obtained when Jr = 1 (butting) and Mr = 2 (steel), and the function f21 (Tr) when Jr = 2 (T-shaped fillet) and Mr = 1 (stainless steel). When Jr = 2 (T-shaped fillet) and Mr = 2 (steel), the function is f22 (Tr), and when Jr = 3 (overlap fillet) and Mr = 1 (stainless steel), the function f31 (Tr). When Jr = 3 (overlapping fillet) and Mr = 2 (steel), the function f32 (Tr) is obtained. The functions f11 (Tr) to f32 (Tr) are defined in advance by a test or the like and set as a welding current calculation function. Specific examples of the functions f11 and f12 are shown below.
Iw = f11 (Tr) = 50.14 × Tr−0.84
Iw = f12 (Tr) = 54.51 × Tr + 5.02

  FIG. 3 is a graph showing the functions f11 and f12. In the drawing, the horizontal axis indicates the plate thickness T (mm), and the vertical axis indicates the welding current Iw. As shown in the figure, when a plate thickness T (mm) is input, an appropriate welding current value Iw is calculated.

  FIG. 4 is a configuration diagram of a welding current calculation function according to a form different from FIG. 2 described above. A function f1 (Mr, Tr to f3 (Mr, Tr)) shown in the figure is built in the above-described welding current setting circuit IWR, which will be described below with reference to the figure.

The welding current calculation function is the function f1 (Mr, Tr) when the joint setting signal Jr = 1 (matching), and the function f2 (Mr, Tr) when the joint setting signal Jr = 2 (T-shaped fillet). When the joint setting signal Jr = 3 (overlapping fillet), the function f3 (Mr, Tr) is obtained. Here, as described above, when the material setting signal Mr is 1, it is stainless steel, and when it is 2, it is steel. The plate thickness setting signal Tr is the plate thickness (mm) of the workpiece. A specific example of the function f1 is shown in the following equation.
Iw = f (Mr, Tr) = a × Tr + b × (Mr + 1) + c × (Mr + 1) × Tr + d
However, a = 41.4, b = 5.86, c = 4.37, and d = -12.56. The graph of the function f1 is the same as that in FIG. The other functions f2 to f3 are optimized so that the values of the above constants a to d are suitable for the respective joint conditions.

In the above-described embodiment of the present invention, when the joint condition, the material to be welded, and the plate thickness are selected by the switch on the front panel of the welding power source, an appropriate welding current Iw is automatically determined by a predetermined welding current calculation function group. Is calculated and set. Further, when the welding current Iw is set, the other parameters (initial current Is, crater current Ic, up slope period Tu, down slope period Td, preflow period Tp, and afterflow period Ta) described above with reference to FIG. The current Iw, the joint setting signal Jr, the material setting signal Mr, and the plate thickness setting signal Tr are automatically set by a predetermined function having variables. For example, the initial current Is can be calculated by the following equation using the welding current Iw and the material setting signal Mr as variables.
Is = e × (Iw) ^p × (Mr + 1) ^q
However, e = 96.2, p = 0.30 and q = 0.24. FIG. 5 is a graph showing this function. In the figure, the horizontal axis represents the welding current Iw, and the vertical axis represents the initial current ratio R [%] = (Is / Iw) × 100. As described above, the material setting signal Mr = 1 when stainless steel is used, and Mr = 2 when steel is used.

  According to the embodiment described above, the appropriate welding current Iw is calculated by a predetermined welding current calculation function only by selecting the joint conditions, the material to be welded, and the plate thickness with the switch on the front panel of the welding power source. Automatically set. For this reason, many years of experience and troublesome labor are not required for setting the welding current Iw. Furthermore, since the number of function groups can be reduced as compared with the configuration of FIG. 2 by making the configuration of the above-described welding current calculation function as described above with reference to FIG. . In addition, the storage capacity can be reduced. Furthermore, the initial current Is, the crater current Ic, the up slope period Tu, the down slope period Td, the preflow period Tp and The afterflow period Ta can also be automatically set to an appropriate value, and the parameter setting time can be shortened.

  In the above-described embodiment, the case where the joint condition, material, and plate thickness are performed by the switch on the front panel of the welding power source is exemplified, but the joint pendant connected to the control device of the welding robot may be selected by communication. good. A circuit for finely adjusting the automatically set welding current Iw may be provided.

  FIG. 6 is a block diagram for adding a current setting alarm function to the non-consumable electrode arc welding power source according to the embodiment of the present invention described above with reference to FIG. This block issues an alarm when the welding current setting signal Iwr exceeds the appropriate range with respect to the diameter of the non-consumable electrode 1 used (hereinafter referred to as electrode diameter). Further, the present block receives the welding current setting signal Iwr of FIG. 1 and issues an alarm and outputs an output prohibition signal St for prohibiting the output of the power supply main circuit PM. Hereinafter, a description will be given with reference to FIG.

  The electrode diameter setting circuit DR outputs an electrode diameter setting signal Dr when the electrode diameter is set by a switch provided on the front panel of the welding power source. The upper limit current setting circuit IM receives the electrode diameter setting signal DR, calculates an upper limit current value that can energize an electrode having the set electrode diameter, and outputs an upper limit current setting signal Im. FIG. 7 is a diagram showing an upper limit current value with respect to an electrode diameter of a TIG welded tungsten electrode or the like. The function shown in this graph is built in the upper limit current setting circuit IM.

  The comparison circuit CP compares the upper limit current setting signal Im and the welding current setting signal Iwr, and outputs an alarm signal Cp that becomes a high level when Iwr ≧ Im. The alarm means KH is a display, a buzzer or the like, and issues an alarm when this alarm signal Cp is input (High level). That is, it lights up or blinks in the case of a display, and sounds an alarm sound in the case of a buzzer.

  When the alarm signal Cp is input (High level), the output prohibition circuit ST outputs the output prohibition signal St to the power supply main circuit PM of FIG. When this output inhibition signal St is output, the output of the welding power source is stopped.

  In the figure, a case where an alarm is issued when the alarm signal Cp is output and the output of the welding power source is prohibited is illustrated. However, it is possible to perform either one of issuing an alarm or prohibiting output. Further, a lower limit current value may be set for the electrode diameter, and an alarm may be issued when the value of the welding current setting signal Iwr is equal to or lower than the lower limit value. The electrode diameter setting circuit DR need not be provided on the front panel, and may be set by a teach pendant in the case of robot welding.

  By adding this block, an alarm can be issued when the value of the welding current setting signal Iwr that is automatically set exceeds the upper limit current value for the electrode diameter. For this reason, it is possible to prevent the electrode from being consumed and the welding quality from being deteriorated. The same applies when the output of the welding power source is prohibited.

It is a block diagram of the non-consumable electrode arc welding power supply which concerns on embodiment of this invention. It is a block diagram of the welding current calculation function group incorporated in the welding current setting circuit IWR of FIG. FIG. 3 is a graph showing welding current calculation functions f11 and f12 shown in FIG. FIG. 4 is another configuration diagram different from FIG. 2 of a welding current calculation function group built in the welding current setting circuit IWR of FIG. 1. It is the figure which represented the function which calculates the initial current Is with the welding current Iw as an input. FIG. 2 is a block diagram for adding a function for issuing an alarm when a value of a welding current setting signal exceeds an upper limit current value with respect to an electrode diameter to the non-consumable electrode arc welding power source of FIG. 1. It is a figure which shows the upper limit electric current value with respect to an electrode diameter. It is a wave form diagram of the discharge signal Gf and output current Io of the shield gas in a prior art.

Explanation of symbols

1 Non-consumable electrode 2 Workpiece 3 Arc 4 Welding torch a to e Constant CP Comparison circuit Cp Alarm signal DR Electrode diameter setting circuit Dr Electrode diameter setting signal EI Current error amplification circuit Ei Current error amplification signals f1 to f3 Functions f11 to f32 Function Gf Shield gas discharge signal Ic Crater current ICR Current control setting circuit ID Current detection circuit Id Current detection signal IM Upper limit current setting circuit Im Upper limit current setting signal Io Output current Ir Output current setting signal Is Initial current Iw Welding current IWR Welding current setting Circuit Iwr Welding current setting signal JR Joint setting circuit Jr Joint setting signal KH Alarm means MR Material setting circuit Mr Material setting signal p, q Constant PM Power supply main circuit R Initial current ratio ST Output prohibition circuit St Output prohibition signal T Thickness Ta After Flow period Td Down slope period Tp Preflow period TR Thickness setting times Tr plate thickness setting signal TS torch switch Ts torch switch signal Tu-up slope period

Claims (4)

In the non-consumable electrode arc welding power source that conducts the welding current set by the welding current setting signal,
A joint setting means for outputting a joint setting signal for setting joint conditions;
Material setting means for outputting a material setting signal for setting the material of the workpiece,
A plate thickness setting means for outputting a plate thickness setting signal for setting the plate thickness of the workpiece,
With the joint setting signal, the material setting signal, and the plate thickness setting signal as inputs, a welding current setting unit that outputs the welding current setting signal according to a predetermined welding current calculation function;
Electrode diameter setting means for outputting an electrode diameter setting signal for setting the diameter of the electrode;
An upper limit current setting unit that outputs an upper limit current setting signal according to the electrode diameter setting signal;
Comparing the upper limit current setting signal and the welding current setting signal, when the value of the welding current setting signal is large, a comparison unit that outputs an alarm signal;
An alarm means for issuing an alarm using the alarm signal as an input;
A non-consumable electrode arc welding power source.   The welding current calculation function is a predetermined function group for calculating the welding current setting signal by inputting the plate thickness setting signal for every combination condition of the joint setting signal and the material setting signal. The non-consumable electrode arc welding power source according to claim 1.   The welding current calculation function is a predetermined function group that calculates the welding current setting signal by inputting the material setting signal and the plate thickness setting signal for every joint condition set by the joint setting signal. The non-consumable electrode arc welding power source according to claim 1. An output prohibition unit for prohibiting the output of the welding power source using the alarm signal as an input;
The non-consumable electrode arc welding power source according to any one of claims 1 to 3, further comprising:

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