KR19980025394A - TIG welding device - Google Patents

Abstract

The present invention relates to a TIG welding apparatus, and in the related art, the AC TIG cycle is fixed and the AC TIG reverse polarity period is for the aluminum cleaning action, whereas the AC TIG period is variable and can be varied. The limitation of the penetration is limited by the limitation, the current concentration alternates with the positive polarity, and the concentration of the arc decreases, and the electron is struck upside down in the reverse polarity period, resulting in high electrode consumption, and the limitation of the positive polarity period. There is a problem that is difficult to use. Therefore, in the present invention, in order to weld a base material made of aluminum and its alloys, in particular, in the case of a thin plate, in order to solve the problems of limitation of penetration depth, arc concentration and large power consumption, and difficulty in use of a filler rod, an AC tag and a cycle and an AC tag A composite tag control unit having a reverse polarity period, a composite tag period, and a composite tag positive polarity period was separately settled.

Description

TIG welding device

1 is a circuit diagram of a conventional TIG welding apparatus.

2 is a waveform diagram of the welding current in FIG.

(A) is a waveform diagram of DC TIG welding current,

(B) is a wave diagram of the AC TIG welding current.

3 is a circuit diagram of a non-consumable arc welding device of the present invention.

4 is a waveform diagram of a welding current in FIG.

(A) is the DC TIG welding current waveform diagram

(B) is the DC TIG welding current waveform diagram,

(C) is the DC TIG welding current waveform diagram,

* Description of the symbols for the main parts of the drawings *

1: first rectifying part 2: smoothing part

3: first inverter unit 4: main transformer

7: second inverter 10: torch

11: Base metal 13: Welding current reference unit

15: current detector 16: DC tag reference section

19: AC TIG Cycle Reference 21: AC TIG Reverse Polarity Reference

25: compound tag reference part 26: compound tag positive reference part

27: composite tag control unit 28: DC / AC composite selection unit

The present invention relates to a tungsten inert gas (TIG) welding apparatus, and in particular, when welding aluminum and its alloys, welding is performed by periodically generating an alternating arc for heating the base material in the positive polarity and cleaning the base material in the reverse polarity. The present invention relates to a TIG welding device for improving welding quality.

TIG (Tungsten Inert Gas) welding device is a welding device that shields air by flowing argon gas, which is an inert gas, between the torch electrode of the welder and the base material to be welded, and generates an electric arc to melt and attach the base material by the heat.

However, if the base material is not aluminum and its alloy, welding is possible by the positive DC TIG welding method using the torch electrode (-) and the base material (+), but if the base material is aluminum and its alloy, In polar welding, welding is impossible because of the chemical property of forming an oxide film on the aluminum surface.

The oxide film is removed by electron emission from the base material by applying the reverse polarity so that the torch electrode is (+) and the base material is (-).

Therefore, when welding aluminum-based materials, the welding is performed by an AC teak welding method that periodically generates an AC arc that heats the base material in the positive polarity and washes the base material in the reverse polarity.

Looking at the prior art with respect to such a method is as follows.

The conventional TIG welding device circuit configuration, as shown in Figure 1, the first rectifier (1) for receiving a commercial AC power and rectified to the pulsating voltage; A smoothing part 2 receiving the pulsating voltage from the first rectifying part 1 and smoothing it with a constant DC voltage using a capacitor; A first inverter part (3) for converting the DC voltage of the smoothing part (2) into high-frequency alternating current and outputting it; A main transformer (4) for receiving the alternating current of the first inverter unit (3) and converting the voltage into a low voltage suitable for welding; A second inverter 5 receiving a smoothed DC voltage through a second DC unit 5 for rectifying the low voltage from the main transformer 4 back to a DC voltage and a current smoothing reactor 6 and outputting DC and AC current waveforms; Part 7; A high pressure high frequency generator 9 for generating a high pressure high frequency; The actual welding current flowing between the torch 10 and the base material 11 is detected from the secondary intermediate tap of the main transformer 4 and the signal for controlling the detected current is compared with the preset welding current. An output current controller 30 outputting the first inverter unit 3; And a second inverter controller 40 for outputting a signal for alternating a DC tag or an AC tag set in advance according to the selection signal to the second inverter unit 7.

The output current control unit 30 includes a welding current reference unit 13 for outputting a preset reference welding current value; A current detector 15 for detecting a real welding current flowing between the torch 10 and the base material 11; A current controller 14 for comparing the set welding current reference value of the welding current reference unit 13 with the actual welding current detected by the current detection 15 to calculate the actual welding current equal to the set reference value; The first inverter driver 12 drives the first inverter unit 3 to produce the output calculated by the current controller 14.

In addition, the second inverter controller 40 includes: a DC tag reference unit 16 which outputs a driving command of the second transistor Tr2 of the second inverter unit 7 set in advance; When the base element is not aluminum and its alloy by controlling the switching element of the second inverter unit 7 by receiving the driving command of the second transistor Tr2 of the second inverter unit 7 from the DC tag reference unit 16. A direct current tag control unit 17 for outputting a driving signal of the second transistor Tr2 of the second inverter unit 7 for welding in a positive polarity manner in which the torch is negative and the base is positive; An AC tag period reference unit 19 for outputting a predetermined AC tag period; An AC tag reverse polarity reference unit 21 for outputting a reverse polarity period corresponding to the reverse polarity of the AC tag; The alternating element of the second inverter unit 7 is alternately operated by receiving an alternating current tag period and an alternating current tag reverse polarity period of the alternating current tag reference unit 19 and the alternating current reverse polarity reference unit 21. AC alloy control unit 20 for outputting a drive signal for welding in the positive and reverse polarity method in the case of an alloy; A DC / AC selector 23 which outputs a signal for controlling whether to select a DC tag or an AC tag according to the material of the base material; A DC / AC switching unit 22 for switching to select an output of the DC tag control unit 17 or the AC tag control unit 20 according to the output signal of the DC / AC selection unit 23; The second inverter driving unit 18 outputs a signal for driving the switching element of the second inverter unit 7 according to a signal input by switching through the DC / AC switching unit 22.

The prior art constructed as described above will be described with reference to FIGS. 1 and 2.

The commercial AC power is rectified to the pulsating voltage by the first rectifying unit 1, which is smoothed to a constant DC voltage through the smoothing unit 2 again.

The DC voltage smoothed through the smoothing unit 2 is input to the first inverter unit 3, converted into a high frequency current, and then applied to the main transformer 4, and the main transformer 4 is The alternating current is transformed to a low voltage suitable for welding and applied to the second rectifier 5.

Accordingly, when the second rectifier 5 rectifies the low voltage back to DC and provides the current smoothing reactor 6, the second rectifying part 5 is smoothed by the current smoothing reactor 6 and applied to the second inverter part 7. .

Then, the second inverter unit 7 switches only the second transistor Tr2, which is a switching element, or switches the first transistor Tr1 and the second transistor Tr2 by the driving signal supplied from the second inverter controller 40. ) Turns on or off alternately to output a direct current or alternating current waveform.

At this time, the high-pressure high-frequency voltage generated by the high-pressure high-frequency generator 9 with the start of the welding machine is applied between the torch 10 and the base material 11 via the choke coil 8 and the condenser C.

Therefore, the insulation between the torch 10 and the base material 11 is broken and a welding current starts to flow.

At this time, argon gas, which is an inert gas, is flowed between the torch 10 and the base material 11 to shield the air, generate an electric arc, and melt the base material by the heat to perform welding.

The output operation of the direct current or alternating current of the welding current flowing between the torch 10 and the base material 11 during welding is performed through a series of controls as follows.

First, the current detector 15 detects a real welding current flowing between the torch 10 and the base material 11, and supplies the detected real welding current to the current controller 14 of the output current controller 30.

Then, the current controller 14 compares the reference current preset in the welding current reference unit 13 with the actual welding current to calculate the actual welding current to be equal to the set value, and calculates the calculated output of the first inverter driver ( 12).

The first inverter driver 12 outputs a driving signal corresponding to an operation value input from the current controller 14 to the first inverter unit 3 to flow a welding current between the torch 10 and the base material 11. To control.

At this time, in the second inverter control unit 40, the DC TIG (TIG) is the second inverter unit so that the torch becomes (-) and the base material 11 becomes (+) from the DC TIG reference unit 16 for positive operation. A drive command for turning on only the second transistor Tr2 of (7) is outputted and applied to the DC tag control unit 17.

Then, the DC tag control unit 17 outputs the driving signal of the second transistor Tr2 to the DC / AC switching unit 22.

In addition, when the AC tag outputs the AC tag period reference unit 19 and the AC tag reverse polarity reference unit 21 to the AC tag control unit 20, the AC tag control unit 20 converts the second inverter unit ( Output the control to drive the first transistor (Tr1) and the second transistor (Tr2) of 7) alternately to drive the alternating cycle is equal to the value of the AC tag reference unit 19, wherein the torch is (+ The reverse polarity period, i.e., becomes equal to the output of the AC TIG reverse polarity reference unit 21.

The output of the AC tag control unit 20 is also applied to the DC / AC switching unit 22.

At this time, if the direct current according to the output of the DC / AC selection unit 23, the output of the DC / AC switching unit 22 is the output of the DC tag control unit 17 and the output of the AC tag control unit 20 if the AC second It is switched to apply to the inverter driver 18.

For example, when the DC / AC selector 23 outputs a signal for selecting DC, the DC / AC switch 22 switches to select the output of the DC tag controller 17.

Then, the second inverter driving unit 18 outputs a signal for turning on the second transistor Tr2 to the second inverter unit 7 and turns it on, thus connecting the torch 10 and the base material 11 to FIG. As in (A), DC TIG welding current flows.

As described above, when the DC TIG welding current is flowed between the torch 10 and the base material 11, welding is performed when the base material 11 is not aluminum and its alloy. Welding is performed in a positive manner in which (+) is set to (+).

When the DC / AC selection unit 23 outputs a signal for selecting AC, the DC / AC switching unit 22 switches to select the output of the AC tag control unit 20.

Then, the second inverter driver 18 outputs a driving signal for alternately turning on the first transistor Tr1 and the second transistor tr2 to the second inverter unit 7, and accordingly, the torch 10 and the base material. Between (11), an alternating current TIG welding current as in (b) of FIG. 2 flows.

As described above, when the alternating current TIG welding current flows between the torch 10 and the base material 11, it is time to perform welding when the base material is aluminum and its alloy. The base material is heated at the positive polarity of (+), the torch electrode is set to (+), and the reverse polarity is applied so that the base material becomes (-) so that the base material is cleaned by the emission of electrons from the base material.

In Fig. 2B, Af is an alternating tag period and Ao is an alternating tag reverse polarity period.

The above operation is repeated to perform welding.

However, in the prior art as described above, in the case of the alternating current tag, the alternating current tag period is fixed as in (b) of FIG. The depth of penetration is limited by the limitation of the positive polarity period in the low current region during the aluminum welding of thin plate, and the concentration of arc is decreased by alternating the current to the positive polarity, and the electron is struck upside down in the reverse polarity period. The consumption of large, there is a problem that it is difficult to use Yonggabong due to the limitation of the positive period.

Therefore, an object of the present invention for solving the conventional problems as described above is to extend the depth of penetration during aluminum welding of thin plate, concentrating the arc by extending the positive polarity period by sending a positive direct current tag output during the alternating current tag welding at regular intervals The present invention provides a TIG welding device that improves welding quality by improving the properties, reducing electrode consumption, and ease of use of the filler rod.

According to the present invention, a TIG welding device circuit configuration for rectifying and smoothing a commercial AC power source through a first rectifying part and a smoothing part is converted into high frequency AC by the first inverter part and is suitable for welding through a main transformer. In the welding apparatus for performing welding by converting the AC voltage into a low voltage and passing through a second rectifying part and a rectifying smoothing reactor, and outputting a direct current or alternating current to the base material 11 and the torch 10 by the second inverter part. The signal for controlling the real welding current flowing between the 10 and the base material 11 from the secondary intermediate tap of the main transformer 4 and controlling the detected current compared with the preset welding current is controlled. An output current control unit 30 outputting to the one inverter unit 3; A welding method controller 50 for outputting a signal for welding the torch and the base material by alternately operating the positive or positive and reverse polarity methods according to a preset DC tag period and an AC tag period; The TIG which receives the AC TIG and its reverse polarity period from the welding method controller 50 and receives the composite TIG cycle and its composite TIG positive polarity period to adjust the TIG period when welding a base material made of aluminum and its alloy. A cycle adjusting unit 60; When the base material is not aluminum and its alloys, the DC and AC tag cycles of the welding method control unit 50 are selected, or when the aluminum base materials having different thicknesses are welded, the composite tag cycles of the tag period control unit 60 are selected. DC / AC / complex switch 24 to perform; A DC / AC / selection unit 28 for outputting a signal for controlling whether to select a DC tag or an AC tag or a composite tag according to the material of the base material; The second inverter driving unit 18 outputs a signal for driving the switching element of the second inverter unit 7 according to a signal input by switching through the DC / AC / composite switching unit 24.

The tag period adjusting unit 60 includes a compound tag period reference unit 25 for outputting a predetermined compound tag period; A composite tag positive polarity reference section 26 for outputting a positive polarity period of the predetermined composite tag; A composite tag control unit 27 is configured to receive an alternating current tag period, an alternating current tag reverse polarity period, a composite tag period, and a composite tag positive polarity period, respectively, and select a period according to a welding state.

Referring to the operation and effect of the present invention configured as described in detail as follows.

The commercial AC power is rectified to the pulsating voltage by the first rectifying unit 1, which is smoothed to a constant DC voltage through the smoothing unit 2 again.

The DC voltage smoothed through the smoothing unit 2 is input to the first inverter unit 3, converted into high frequency AC, and then applied to the main transformer 4, and the main transformer 4 is applied to the high frequency input. The alternating current is transformed to a low voltage suitable for welding and applied to the second rectifier 5.

Accordingly, when the second rectifier 5 rectifies the low voltage back to DC to provide the current smoothing reactor 6, the second rectifying part 5 smoothes the current by the current smoothing reactor 6 and applies it to the second inverter part 7. do.

Then, the second inverter unit 7 switches only the second transistor Tr2, which is a switching element, or switches the first transistor Tr1 and the second transistor Tr2 by the driving signal supplied from the second inverter driver 18. ) Alternately turns on or off to output a DC or AC current waveform.

At this time, the high-pressure high-frequency voltage generated by the high-pressure high-frequency generator 9 with the start of the welding machine is applied between the torch 10 and the base material 11 via the choke coil 8 and the condenser C.

Therefore, as the insulation between the torch 10 and the base material 11 is broken, a welding current starts to flow between the torch and the base material.

In order to flow a desired welding current between the torch 10 and the base material 11, the current detector 15 of the output current controller 30 detects a real welding current and is fed back to the current controller 14.

The current controller 14 compares the reference current set by the welding current reference unit 13 with the feedback time, calculates the actual welding current to be equal to the set value, and applies the output to the first inverter driver 12.

The first inverter driver 12 outputs a driving signal according to the output applied from the current controller 14 to the first inverter unit 3 to adjust the welding current.

At this time, in the low-temperature control unit 50, the DC TIG is configured so that the torch 10 becomes negative (-) and the base material 11 becomes positive from the DC tag reference unit 16 for positive operation. A drive command for turning on only the second transistor Tr2 of the inverter unit 7 is output and is applied to the DC tag controller 17.

Then, the DC tag control unit 17 outputs the driving signal of the second transistor Tr2 to the DC / AC / composite switching unit 24.

In addition, when the AC TIG output of the AC TIG cycle reference unit 19 and the AC TIG reverse polarity period output of the AC TIG reverse polarity reference unit 21 are applied to the AC TIG control unit 20, The AC tag control unit 20 outputs an output for controlling to drive the first transistor Tr1 and the second transistor Tr2 of the second inverter unit 7 alternately, but the alternating period is the AC tag reference unit 19. The reverse polarity period during which the torch becomes positive is equal to the output of the AC tag reverse polarity reference section 21.

The output of the AC tag control unit 20 is also applied to the DC / AC / complex switching unit 24.

The composite tag (TIG) is the AC tag period output of the AC tag reference unit 19, the AC tag reverse polarity period output of the AC tag reverse polarity reference unit 21, and the compound tag period reference in the tag period control unit 60. The composite tag control unit 27 receives the composite tag period output of the unit 25 and the composite tag positive polarity period output of the compound tag positive polarity reference unit 26, respectively, to produce an output as shown in FIG. 4C. Perform the operation.

That is, the control unit outputs an alternating current output (TIG) output in the composite tag period-composite TIG positive polarity period (Mf-Mo) and outputs the direct current TIG output in the composite TIG positive polarity period (Mo).

Therefore, in the composite TIG period-composite TIG positive period (Mf-Mo), an output for controlling the first transistor Tr1 and the second transistor Tr2 of the second inverter unit 7 to be alternately driven is output. The period is equal to the value of the AC tag reference unit 19, and the reverse polarity period in which the torch 10 becomes positive is equal to the output of the AC tag reverse polarity reference unit 21.

When the period as described above expires, the DC / AC / composite switching unit (b) transmits the drive signal of the second transistor Tr2 of the second inverter unit 7 to output the positive polarity in the next multi-tag positive polarity period Mo. Output to 24).

In this case, the DC / AC / composite switching unit 24 switches and outputs the output according to the DC / AC / complex selection unit 28. If DC, the DC / AC / complex switching unit 24 outputs a DC tag. If the output of the control unit 17 is alternating current, the output of the AC tag control unit 20 is changed, and if it is a combination, the output of the composite tag control unit 27 is applied to the second inverter drive unit 18.

As described in detail above, the present invention is provided with a DC / AC / composite selection section to output a positive DC tag output during alternating current TIG welding at regular intervals, thereby expanding the overall polarity period and expanding the depth of penetration during aluminum welding. As a result, the concentration of the arc, the decrease in electrode consumption, and the ease of use of the used electrode can be improved, and the welding quality can be improved, and in particular, the welding of aluminum base materials having different thicknesses and the respective welding can be applied.

Claims (2)

Direct current rectified and smoothed through the first rectifier and the smoother is converted to high frequency alternating current by the first inverter, and is transformed into an AC low voltage suitable for welding by the main transformer, followed by a second rectifier and a current smoothing reactor. In the welding apparatus which outputs a direct current or alternating current to a base material and a torch by a 2nd inverter part, and performs the welding, the real welding current which flows between the said torch and a base material is detected, and this detected current is preset with the welding. An output current controller for outputting a signal for controlling in comparison with current to the first inverter unit; A welding method controller for outputting a signal for welding the torch and the base material by alternately operating the positive or positive and reverse polarity methods according to a preset DC tag period and an AC tag period; Tig period control unit for receiving the alternating current tag and its reverse polarity period from the welding method control unit and the composite tag period and its composite tag positive polarity period to adjust the tag period during welding of the base material made of aluminum and its alloy; ; DC / AC / composite clause to select the DC and AC tag cycles of the welding method control part or the composite tag cycle of the TIG cycle control part when welding the aluminum base material of different thickness when the base material is aluminum or its alloy or not. Affected areas; A DC / AC / composite selection unit for outputting a signal for controlling whether to select a DC tag or an AC tag or a composite tag according to the material of the base material; And a second inverter driving unit configured to output a signal for driving the switching element of the second inverter unit according to a signal input by switching through the DC / AC / composite switching unit. The apparatus of claim 1, wherein the tag period control unit comprises: a compound tag period reference unit configured to output a predetermined compound tag period; A composite tag positive polarity reference unit for outputting a predetermined positive period of the composite tag; A TIG welding device comprising: an AC TIG cycle, an AC cycle reverse polarity period, a composite TIG cycle, and a TIG positive polarity period, respectively, and a composite cycle control unit configured to select a cycle according to a welding state.