JP5473064B2 - Arc welding equipment - Google Patents

Description

  The present invention relates to an improved arc welding apparatus for performing gas shielded arc welding.

  In consumable electrode type or non-consumable electrode type gas shielded arc welding, shield gas such as carbon dioxide gas and argon gas is blown out to the arc and molten pool to shield it from the atmosphere, and the atmosphere enters the welding atmosphere. It is necessary to prevent. It is important that the flow rate of the shielding gas is within a certain allowable range. When the gas flow rate is small, the arc state becomes unstable due to the intrusion of the atmosphere into the welding atmosphere, so that blowholes are generated or a large amount of spatter is generated. Conversely, if the gas flow rate is too high, turbulent flow may occur, resulting in poor shielding or insufficient melting. As a result, the appearance of the weld bead may be deteriorated, resulting in poor welding.

  In a general arc welding apparatus that outputs or stops a shield gas by controlling the opening and closing of the solenoid valve, an excessive flow of shield gas is generated when the solenoid valve is opened, that is, during the preflow process required when starting welding. Is output. This phenomenon is expressed as rush current below. The peak flow and duration of the rush flow vary depending on the pipe length, pipe diameter, pressure, gas OFF interval time, set flow rate, etc., so the time from the start of shield gas output until the flow rate falls within the allowable range Different. An example is shown below. The gas OFF interval time described above means an interval time from when the shield gas is stopped until the next output is started.

  FIG. 7 is a diagram for explaining a state of a rush of shielding gas. The figure shows how the gas flow rate changes with time after the shield gas output is started when the set flow rate is 15 liters / minute. The horizontal axis is the elapsed time after starting the output of the shield gas (hereinafter referred to as gas ON elapsed time), and the vertical axis is the gas flow rate at that time. FIG. 5A shows the flow rate change when the gas OFF interval time is 4 seconds. Similarly, FIG. 7B shows the flow rate change at 3 seconds, FIG. 10C shows 2 seconds, FIG. 10D shows 1 second, and FIG. 9E shows 0.5 seconds. . As shown in the figure, for a while after opening the solenoid valve, an excessive flow of shielding gas is output due to rush current, and with the passage of time, the set flow rate determined by the gas flow setter (15 liters in the figure). / Min).

  As described above, conventionally, since the shield gas having an excessive flow rate is ejected due to the generation of the rush current, the shield gas is consumed wastefully. In recent years, there has been a great demand for saving the shielding gas consumption (hereinafter simply referred to as gas consumption) from the viewpoints of energy saving, ecology, cost reduction, and the like.

  Techniques for solving the above problems are disclosed in Patent Documents 1 and 2. Patent Document 1 discloses a welding apparatus provided with a mechanical gas flow rate control means such as an orifice (hereinafter referred to as Prior Art 1). Patent Document 2 discloses a gas processing apparatus that dynamically controls a gas flow rate using a mass flow controller as a gas flow rate control means (hereinafter referred to as Prior Art 2). According to the prior arts 1 and 2, by providing the gas flow rate control means for suppressing the rush flow at the welding start portion, there is an effect that the gas consumption can be saved.

  However, although it can be understood that the prior arts 1 and 2 saved the gas consumption, there is no way to grasp the saving effect. That is, for example, it is not possible to easily know how much money has been reduced by introducing the equipment. In this regard, Patent Document 3 includes a measuring device that monitors the usage status of each facility such as electric power, gas, oil, and water, and can calculate energy consumption or amount of money by comparing with past performance values. An energy control system that can be used is disclosed (hereinafter referred to as Prior Art 3). According to this prior art 3, the energy saving effect can be grasped by calculating the energy consumption amount or the money amount.

  The above-described conventional techniques 1 to 3 are summarized as follows. Saving gas consumption by introducing gas flow control means (adjustment mechanism using orifices, mass flow controller capable of dynamic control, etc.) to control the flow rate of shield gas in the arc welding equipment Can do. And in order to grasp the saving effect of shielding gas (hereinafter simply referred to as saving amount) by introducing the gas flow rate control means, a gas flow measuring device for monitoring the usage status is further introduced and gas consumption is introduced. The amount of saving is calculated by measuring the amount and comparing the consumption before the introduction of the gas flow rate control means with the consumption after the introduction. However, even if the conventional techniques are combined, there are problems to be described later.

JP 2006-326677 A Japanese Patent Laid-Open No. 8-200434 JP 2003-50626 A

  FIG. 8 is a diagram for explaining the concept of the amount of shielding gas saved. This figure shows how the gas flow rate changes according to the gas ON elapsed time when the set flow rate is, for example, 15 liters / minute, as in FIG. 7 described above. In FIG. 5A, a waveform Ha indicates a waveform of gas consumption (past gas consumption) when the shield gas is output with only one solenoid valve. A waveform Hb shows a waveform when the above-described adjustment mechanism of the related art 1 is introduced as the gas flow rate control means (current gas consumption). A region indicated by hatching is a difference in consumption (integrated value) between the waveform Ha and the waveform Hb, that is, a shield gas saving amount Gsa.

  On the other hand, in FIG. 5B, the waveform Ha is the same as FIG. A waveform Hc indicates a waveform when the gas flow rate is controlled by the mass flow controller of the above-described related art 2 as the gas flow rate control means. A region indicated by hatching is a difference in consumption (integrated value) between the waveform Ha and the waveform Hc, that is, a shield gas saving amount Gsb.

  In order to grasp the saving amount of shield gas, it is necessary to compare the past gas consumption (waveform Ha) and the current gas consumption (waveform Hb or waveform Hc). In order to make this comparison, it is necessary to measure the gas consumption before and after the introduction of the gas flow rate control means using a gas flow rate measuring device. For this reason, it has the subject that it will become the work | work which requires a man-hour very much.

  Further, since the rush flow described above is a transient phenomenon until a steady state is reached, the gas flow rate cannot be measured unless a highly accurate gas flow measuring device is used. Since high-precision gas flow rate measuring instruments are expensive, there is a problem that introducing them leads to an increase in cost.

  Therefore, an object of the present invention is to provide an arc welding apparatus that can easily grasp the saving effect of shielding gas obtained when a gas flow rate control means is introduced without using a special measuring instrument. It is said.

The first invention is
In an arc welding apparatus having a gas flow rate control means for suppressing a rush of shield gas, and starting or stopping the output of shield gas at a timing based on external signal input or pre-created teaching data,
Measuring means for measuring the gas ON elapsed time from the start of output of the shield gas to the output stop and the gas OFF interval time from the output stop to the start of output;
A storage unit that stores a plurality of gas saving amount characteristic tables in which a relationship between the gas ON elapsed time and the saving amount of shield gas is determined in advance for each gas OFF interval time;
Table selecting means for selecting one of a plurality of gas saving amount characteristic tables according to the measured gas OFF interval time;
A gas saving amount calculating means for inputting the gas ON elapsed time to the selected gas saving amount characteristic table and calculating a saving amount for each output of the shield gas;
Effect value calculating means for calculating a saving effect value obtained by integrating the saving amount;
Display means for displaying the saving effect value;
An arc welding apparatus comprising:

  According to a second aspect of the present invention, when the gas saving amount characteristic table corresponding to the measured gas OFF interval time does not exist, the selection unit performs a new operation by interpolating a plurality of existing gas saving amount characteristic tables. The arc welding apparatus according to the first invention is characterized in that a gas saving amount characteristic table is created and selected.

  A third aspect of the invention is the arc welding apparatus according to the second aspect of the invention, wherein the gas flow rate control means is a mass flow controller that outputs, stops, and adjusts the flow rate of the shield gas by external signal input. is there.

  According to a fourth aspect of the invention, in the first to third aspects, the saving effect value includes a reduction amount obtained by multiplying the integrated value of the saving amount by a predetermined gas unit price. Arc welding equipment.

  A fifth invention is the arc welding apparatus according to the fourth invention, wherein the gas unit price can be changed by a teach pendant for creating the teaching data.

  According to the first invention, the gas ON elapsed time from the output start of the shield gas to the output stop and the gas OFF interval time from the output stop to the output start are measured, and the relationship between these times and the gas saving characteristic table The saving amount for each output of the shielding gas is calculated based on the above, and the saving effect value obtained by integrating the saving amount is calculated and displayed on the display means. This makes it possible to easily grasp the saving effect of the shielding gas obtained when the gas flow rate control means is introduced without using a special measuring instrument.

  According to the second invention, when there is no gas saving amount characteristic table corresponding to the measured gas OFF interval time, a new gas saving amount is obtained by performing interpolation calculation of the plurality of existing gas saving amount characteristic tables. A characteristic table is created. Since the gas saving amount characteristic table should be prepared in advance according to the pattern of the gas OFF interval time, in order to calculate the saving amount with high accuracy, a considerable number of gas OFF interval times are assumed and an experiment is performed. It is necessary to determine in advance. In the second invention, when there is no gas saving amount characteristic table, a new table is created based on the existing table, so that a considerable number of gas saving amount characteristic tables are stored. Even if not, the effect of the first invention can be exhibited.

  According to the third aspect of the invention, the mass flow controller that outputs, stops, and adjusts the flow rate of the shield gas by an external signal input is used as the gas flow rate control means. Although mechanical means such as an orifice has an effect of suppressing the turbulence, the turbulence itself cannot be completely suppressed. Further, the gas flow rate cannot be controlled to a desired value. On the other hand, the mass flow controller can control the flow rate very finely by a set flow rate signal from the outside. In the third invention, by using the mass flow controller, in addition to the effects produced by the first and second inventions, the shielding gas can be further saved.

  According to the fourth aspect of the invention, the gas unit price, which is the amount of money per unit amount of the shielding gas, is stored in advance, and the amount of reduction is displayed by multiplying the calculated integrated value of the saved amount by the gas unit price. Yes. Thereby, in addition to the effects produced by the first to third inventions, the effect of saving the shielding gas can be grasped by the amount of money.

  According to the fifth aspect, since the gas unit price can be changed by the teach pendant, in addition to the effect produced by the fourth aspect, it is possible to easily cope with the fluctuation of the gas unit price.

It is a block diagram of the arc welding apparatus which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the internal structure of the robot controller which concerns on this invention. It is a graph which shows an example of a gas saving amount characteristic table. It is a flowchart for demonstrating the flow of the output start process of shield gas. It is a flowchart for demonstrating the flow of the output stop process of shield gas. It is a block diagram of the arc welding apparatus which concerns on Embodiment 2 of this invention. It is a figure for demonstrating the mode of the rush of gas. It is a graph for demonstrating the saving amount of shielding gas.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on examples with reference to the drawings.

[Embodiment 1]
FIG. 1 is a configuration diagram of an arc welding apparatus 1 according to the present invention. As shown in the figure, the arc welding apparatus 1 is roughly constituted by a manipulator 14, a teach pendant 15, a robot controller 16, and a welding power source 3.

  In the figure, a manipulator 14 automatically performs arc welding on a workpiece 2, and includes a plurality of arm portions and a wrist portion, and a plurality of servo motors (not shown) for rotationally driving them. And is composed of. A welding torch 7 is attached to the tip of the upper arm of the manipulator 14. The welding torch 7 is for guiding a welding wire 13 having a diameter of about 1 mm wound around a wire reel (not shown) to a taught welding line on the workpiece 2.

  The teach pendant 15 inputs each teaching point and welding condition (welding current, welding voltage welding speed, gas flow rate setting value, etc.) of the section in which welding is performed as teaching data Dw, and a gas saving amount characteristic table Gt and For example, the gas unit price Kg is set in advance, and these are input to the robot controller 16. Further, the output of the shield gas can be confirmed by operating the teach pendant 15. More specifically, a gas output operation signal Go is input to the robot controller 16 by pressing a gas confirmation button (not shown) provided on the teach pendant 15. The teach pendant 15 also functions as a display means, and displays the total saving amount Gst, the total reduction amount Kt, and the saving amount Gsp in units of teaching data as a saving effect value, which will be described later, to the operator. Inform the saving effect.

  The robot controller 16 interprets the teaching data Dw input from the teach pendant 15 and outputs an operation control signal Mc to the manipulator 14 at a predetermined timing based on the interpretation result. Similarly, a welding control signal Ws, a gas output signal Mg, and a gas flow rate setting signal Ms are output to the welding power source 3. Further, a gas output signal Mg is output to the welding power source 3 based on the gas output operation signal Go input from the teach pendant 15. The robot controller 16 corresponds to measurement means, storage means, table selection means, gas saving amount calculation means, and effect value calculation means.

  The welding power source 3 inputs the welding control signal Ws from the robot controller 16 and supplies power between the welding torch 7 and the workpiece 2. Further, with the gas output signal Mg and the gas flow rate setting signal Ms as inputs, a command signal for outputting or stopping the shield gas or setting the flow rate of the shield gas is output to the mass flow controller 31 described later.

  The mass flow controller 31 is connected to the welding power source 3 and outputs or stops the shielding gas in accordance with an input from the welding power source 3. Further, the flow rate of the shield gas supplied from the gas cylinder 30 is adjusted so that the gas flow rate setting value set in advance is obtained.

  FIG. 2 is a functional block diagram showing the internal configuration of the robot controller 16. The robot controller 16 includes a microcomputer, various memories, and the like. More specifically, the main controller 21, the hard disk 22, the trajectory planning unit 23, the RAM 8 as a temporary calculation area, and a timer for measuring time 9, a buffer 24, a servo control unit 25, a servo drive unit 26, a current position monitoring unit 27, and a welding control unit 28.

  The hard disk 22 as a storage means is a non-volatile memory. The teaching data Dw, the gas saving amount characteristic table Gt, and the gas unit price Kg are stored in advance, and the calculated total saving amount Gst, the total reduction amount Kt, and the teaching data unit. Is stored. The gas saving amount characteristic table Gt is data in which the relationship between the gas ON elapsed time from the start of output of shield gas to the stop of output and the saving amount of shield gas is determined in advance. A plurality of models are stored for each gas OFF interval time until the start of output. The total saving amount Gst is a total saving amount of shielding gas in the entire arc welding apparatus 1. The total reduction amount Kt is a value obtained by converting the total saving amount Gst. The saved amount Gsp in the teaching data unit is a saving amount of the shield gas in the taught data Dw unit. Details of the gas saving amount characteristic table Gt, the total saving amount Gst, the total reduction amount Kt, and the saving amount Gsp in units of teaching data will be described later.

  The main control unit 21 reads the teaching data Dw stored in the hard disk 22 for each teaching step and analyzes the contents. For example, the main control unit 21 reads a movement command (consisting of data such as coordinates and speed information) included in the teaching data Dw and notifies the trajectory planning unit 23 of the movement command. Further, the timing for starting and ending the gas output is obtained and notified to the trajectory planning unit 23.

  Further, the main control unit 21 performs processing for calculating the total saving amount Gst, the total reduction amount Kt, and the teaching data unit saving amount Gsp as the saving effect value, and displays the display output signal Dc for displaying them as a teach pendant. Or output to 15.

  The trajectory planning unit 23 stores various movement commands sent from the main control unit 21 in the buffer 24. This movement command is also given gas output / stop timing and the like. Further, the trajectory planning unit 23 reads out the movement command stored in the buffer 24, makes a trajectory plan for the welding torch 7 based on the command, and servo-controls information such as the rotation angle and rotation speed of each motor of the manipulator 14. Notify the unit 25.

  The buffer 24 includes a so-called first-in first-out (FIFO) memory, and stores a movement command sent from the trajectory planning unit 23.

  The servo control unit 25 sends a drive signal to the servo drive unit 26 to rotationally drive each motor of the manipulator 14 based on the track plan sent from the track planning unit 23. The servo control unit 25 acquires an output from an encoder (not shown) and sends the information to the current position monitoring unit 27.

  The servo drive unit 26 outputs an operation control signal Mc to each motor based on a command from the servo control unit 25.

  The current position monitoring unit 27 monitors the current position of the welding torch 7 based on a detection signal from an encoder (not shown) provided in each motor of the manipulator 14.

  The welding control unit 28 outputs various commands from the current position monitoring unit 27 to the welding power source 3 at an appropriate processing timing, thereby causing welding by the welding torch 7 and ejection of shield gas. More specifically, the welding control unit 28 requires a gas output signal Mg and a gas flow rate setting signal Ms necessary for causing the welding power source 3 to eject the shielding gas at the processing timing specified by the current position monitoring unit 27. Is output. Further, the welding control unit 28 outputs a welding control signal Ws for performing welding by the welding power source 3 based on the welding control command from the current position monitoring unit 27. In addition, the welding control unit 28 instructs the timer 9 to measure the gas ON elapsed time and the gas OFF interval time necessary for calculating the gas saving amount at the timing of starting or stopping the output of the shield gas.

  Next, the operation of the arc welding apparatus 1 will be described.

  When an activation signal is input to the robot controller 16, the main control unit 21 interprets the teaching data Dw, performs a trajectory plan or the like, and outputs an operation control signal Mc to each motor of the manipulator 14 based on the calculation result. The welding power source 3 outputs a welding control signal Ws, a gas output signal Mg, a gas flow rate setting signal Ms, and the like. As a result, the welding torch 7 reaches the welding start position, and a shield gas corresponding to the gas flow rate set value is output. After starting the welding, the welding torch 7 is moved to the welding end position, and then the welding is ended. Afterflow control is performed to stop the output of the shield gas. When the gas output operation signal Go is input from the teach pendant 15, the welding control unit 28 outputs the gas output signal Mg to the welding power source 3. As a result, shield gas is output from the welding torch 7. When the input of the gas output operation signal Go is canceled, the gas output signal Mg is turned off. As a result, the output of the shielding gas is stopped.

  As described above, the arc welding apparatus 1 of the present invention outputs and stops the shield gas at a predetermined timing based on the teaching data Dw. Further, the shield gas is output and stopped at an arbitrary timing based on the gas output operation signal Go. In the present invention, the saving amount is calculated when the shield gas is output and stopped. Hereinafter, a method for calculating the saving amount will be described in detail.

  First, the gas saving amount characteristic table Gt will be described. The gas saving amount characteristic table Gt is stored in the hard disk 22 in advance.

  FIG. 3 is a graph showing an example of the gas saving amount characteristic table Gt. The gas saving amount characteristic table Gt integrates the waveform Ha and the waveform Hb (or the waveform Ha and the waveform Hc) described in FIG. 8, regards the difference as the gas saving amount, and sets the gas ON elapsed time as the time axis. Modeled. The horizontal axis represents the gas ON elapsed time [second], and the vertical axis represents the gas saving amount [liter] corresponding to the gas ON elapsed time.

  In the figure, waveforms Xa to Xc respectively show waveforms when the gas OFF interval time is 1 second, 2 seconds, and 4 seconds. As described above, the gas flow rate differs depending on the pipe length, pipe diameter, pressure, gas OFF interval time, set flow rate, and the like. More specifically, as described with reference to FIG. 7, the peak flow rate at the time of rush depends greatly on the gas OFF interval time in addition to the pipe length, the pipe diameter, and the pressure. On the other hand, the duration of the rush depends greatly on the set flow rate. When the set flow rate is small, the difference between the peak flow rate of the rush flow and the set flow rate is large, so it takes time to converge (the continuation time of the rush flow becomes long). When the set flow rate is large, the difference between the peak flow rate of the rush flow and the set flow rate is small, so the convergence time is fast (the continuation time of the rush flow is short). That is, the saving amount depends on the gas OFF interval time and the set flow rate.

  The pipe length, pipe diameter, and pressure can be treated as constant constants as long as the welding environment does not change. Furthermore, when the set flow rate is not changed by the mass flow controller 31 according to the welding site, the set flow rate can also be handled as a constant. That is, only the gas OFF interval time can be handled as a variable. Therefore, as shown in FIG. 3, a plurality of gas saving amount characteristic tables Gt are created for each gas OFF interval time which is a variable.

  When the set flow rate is changed by the mass flow controller 31 according to the welding site, the gas OFF interval time and the set flow rate are handled as variables. That is, a plurality of sets of gas saving amount characteristic tables Gt created for each gas OFF interval time are further created for each set flow rate.

  The gas OFF interval time is preferably set in increments of a predetermined interval (for example, 1 second as shown), and a maximum value is determined. As will be described later, in the process for calculating the gas saving amount, one of the prepared gas saving amount characteristic tables Gt is selected according to the measured gas OFF interval time. . By setting the gas OFF interval time in increments of a predetermined interval and creating a table for each predetermined interval, if there is no table corresponding to the measured gas OFF interval time, an interpolation calculation is performed on the existing table. Can be created. Furthermore, it is desirable that the gas saving amount characteristic table Gt be configured so that it can be corrected by the teach pendant 15 or arbitrarily created according to the welding construction environment.

  Next, with reference to FIGS. 4 and 5, a process for calculating the gas saving amount using the gas saving amount characteristic table Gt will be described. This process is performed by the above-described units of the robot controller 16. The shield gas output / stop control is executed at the timing based on the teaching data Dw or at the timing based on the gas output operation signal Go from the teach pendant 15. There is no big difference. Therefore, in the following, the timing will be described without particular distinction.

  FIG. 4 is a flowchart for explaining a flow of shield gas output start processing.

  In step S <b> 11, the welding control unit 28 outputs a gas output signal Mg to the welding power source 3. As a result, the output of the shielding gas is started.

  In step S12, the timer 9 starts measuring the gas ON elapsed time Ton. This measurement is continued until the output of the shield gas is stopped in step S22 (see FIG. 5) described later.

  In step S <b> 13, the measurement of the gas OFF interval time Tint by the timer 9 is finished, the value is acquired and stored in the RAM 8. The reason for ending the measurement of the gas OFF interval time Tint is that the measurement of the gas OFF interval time Tint is started after the output of the shield gas is stopped in step S25 (see FIG. 5) described later.

  Through the above processing, the gas OFF interval time Tint necessary for calculating the gas saving amount is acquired.

  FIG. 5 is a flowchart for explaining the flow of the shield gas output stop process. In this process, a gas saving amount is calculated.

  In step S <b> 21, the welding control unit 28 turns off the gas output signal Mg and outputs it to the welding power source 3. As a result, the output of the shielding gas is stopped.

  In step S <b> 22, the measurement of the gas ON elapsed time Ton by the timer 9 is finished, and the value is acquired and stored in the RAM 8.

  In step S23, the main control unit 21 selects one of the plurality of gas saving amount characteristic tables Gt according to the gas OFF interval time Tint acquired in step S13. Further, when changing the set flow rate depending on the welding site, the set flow rate is selected according to a preset gas flow rate set value and a gas OFF interval time Tint. At this time, if there is no table corresponding to the gas OFF interval time Tint or the gas flow rate setting value, two tables existing in close proximity are selected and newly created and selected by interpolation calculation. You can do it.

  In step S24, the main control unit 21 inputs the gas ON elapsed time Ton acquired in step S22 to the selected gas saving amount characteristic table Gt, and calculates the saving amount Gs for each output of the shield gas. Here, with reference to FIG. 3 again, an example of calculating the saving amount for each output of the shielding gas will be described. For example, when the gas OFF interval time Tint is 2.0 seconds, the waveform Xb in FIG. 3 is selected. Then, when the gas ON elapsed time Ton acquired in step S22 is 1.5 seconds, this value is input to the horizontal axis, the intersection with the waveform Xb is obtained, and the gas saving amount on the vertical axis is calculated. In this example, the saving amount Gs for each output of the shielding gas is 0.35 liters.

  Returning to FIG. 5, in step S25, measurement of the gas OFF interval time Tint is started. Note that step S25 and steps S23 to S24 described above may be reversed.

  In step S26, it is determined whether or not the teaching gas is being output because the teaching gas has been output. In the case of No (that is, gas output by the gas output operation signal Go from the teach pendant 15), the process proceeds to step S28. In the case of Yes, it transfers to step S27.

  In step S27, the saved amount Gsp of the teaching data unit is updated. That is, the saving amount Gs for each output of the shielding gas calculated in step S24 is added to the current saving amount Gsp.

  In step S28, the total saving amount of shield gas is updated. That is, the saving amount Gs for each output of the shielding gas calculated in step S24 is added to the current total saving amount Gst.

  In step S29, the total reduction amount Kt obtained by converting the total saving amount Gst of the shield gas into an amount is updated. That is, a value obtained by multiplying the saving amount Gs for each output of the shielding gas by the gas unit price Kg is added to the current total reduction amount Kt.

  Through the above processing, the amount of shielding gas saved is calculated. Thereafter, the calculated saving effect values (total saving amount Gst, total reduction amount Kt and teaching data unit saving amount Gsp) are output and displayed on the teach pendant 15. The output display timing may be set when the reproduction of the teaching data Dw is completed, when the teach pendant 15 is operated by the operator to request the display of the saving effect value, or both.

[Embodiment 2]
Next, Embodiment 2 of the present invention will be described. The difference from the first embodiment is that a gas electromagnetic valve 19 is used as the shield gas output control means, and an adjusting mechanism such as an orifice is used as the gas flow rate control means.

  FIG. 6 is a configuration diagram of an arc welding apparatus according to Embodiment 2 of the present invention. Hereinafter, differences from the first embodiment will be described. In the figure, a gas solenoid valve 19 is connected to the welding power source 3 and opens and closes the solenoid valve in response to an input from the welding power source 3. The welding power source 3 receives the gas output signal Mg from the robot controller 16 and outputs a command signal for outputting or stopping the shield gas to the gas electromagnetic valve 19. The adjustment mechanism 20 corresponding to the gas flow rate control means is, for example, an orifice, a tube, or a chamber disclosed in the related art 2.

  Also in the second embodiment configured as described above, similarly to the first embodiment, the saving amount of the shield gas can be calculated. That is, the gas saving amount characteristic table Gt for calculating the saving amount Gsa shown in FIG. 8A is stored in advance, and the processing described with reference to FIG. By performing the processing described in 5, it is possible to easily calculate the saving amount of the shielding gas and inform the operator of the saving effect.

  As described above, the gas ON elapsed time Ton from the output start of the shield gas to the output stop and the gas OFF interval time Tint from the output stop to the output start are measured, and these times and the gas saving amount characteristic table Gt are calculated. A saving amount Gs for each output of the shield gas is calculated based on the relationship, and a saving effect value (total saving amount Gst, total reduction amount Kt and saving amount Gsp in teaching data unit) obtained by integrating the saving amount is calculated. The information is displayed on the teach pendant 15 as a display means. As a result, the shielding gas saving effect obtained when the gas flow rate adjusting means (the mass flow controller 31, the adjusting mechanism 20, etc.) is introduced can be easily grasped without using a special measuring instrument.

  Further, since the gas saving amount characteristic table Gt should be prepared in advance according to the pattern of the gas OFF interval time Tint, in order to calculate the saving amount with high accuracy, the gas OFF interval time Tint is a considerable number. It is assumed that it must be determined in advance through experiments. When the gas saving amount characteristic table Gt corresponding to the measured gas OFF interval time Tint does not exist, a new gas saving amount characteristic table Gt is created by performing an interpolation operation on the plurality of existing gas saving amount characteristic tables Gt. Like to do. As a result, the above-described effects can be exhibited without storing a considerable number of gas saving amount characteristic tables Gt.

  In the first embodiment, the mass flow controller 31 that outputs, stops, and adjusts the flow rate of shield gas by external signal input is used as the gas flow rate control means. Although mechanical means such as an orifice have an effect of suppressing the turbulence, the generation of the turbulence itself cannot be completely suppressed. Further, the gas flow rate cannot be controlled to a desired value. On the other hand, the mass flow controller 31 can perform very fine flow rate control by a set flow rate signal from the outside. That is, by using the mass flow controller 31, the shielding gas can be further saved.

  Further, the gas unit price Kg, which is the amount of money per unit amount of shield gas, is stored in advance, and the total reduction amount Kt is displayed by multiplying the calculated total saving amount Gst by the gas unit price Kg. As a result, the effect of saving the shielding gas can be grasped by the amount of money.

  Further, since the gas unit price Kg can be changed by the teach pendant 15, it is possible to easily cope with the fluctuation of the gas unit price.

DESCRIPTION OF SYMBOLS 1 Arc welding apparatus 2 Workpiece 3 Welding power supply 7 Welding torch 8 RAM
9 Timer 13 Welding wire 14 Manipulator 15 Teach pendant 16 Robot controller 19 Gas solenoid valve 20 Adjustment mechanism 21 Main control unit 22 Hard disk 23 Trajectory planning unit 24 Buffer 25 Servo control unit 26 Servo drive unit 27 Current position monitoring unit 28 Welding control unit 30 Gas cylinder 31 Mass flow controller Dc Display output signal Dw Teaching data Go Gas output operation signal Gs Saving amount Gsa Saving amount Gsb Saving amount Gsp Saving amount Gst of teaching data unit Total saving amount Gt Gas saving amount characteristic table Ha waveform Hb waveform Hc waveform Hc Display output signal Kg Gas unit price Kt Total reduction amount Mc Operation control signal Mg Gas output signal Ms Gas flow rate setting signal Tint Interval time Ton Elapsed time Ws Welding control signal Xa waveform Xb waveform Xc waveform

Claims (5)

In an arc welding apparatus having a gas flow rate control means for suppressing a rush of shield gas, and starting or stopping the output of shield gas at a timing based on external signal input or pre-created teaching data,
Measuring means for measuring the gas ON elapsed time from the start of output of the shield gas to the output stop and the gas OFF interval time from the output stop to the start of output;
A storage unit that stores a plurality of gas saving amount characteristic tables in which a relationship between the gas ON elapsed time and the saving amount of shield gas is determined in advance for each gas OFF interval time;
Table selecting means for selecting one of a plurality of gas saving amount characteristic tables according to the measured gas OFF interval time;
A gas saving amount calculating means for inputting the gas ON elapsed time to the selected gas saving amount characteristic table and calculating a saving amount for each output of the shield gas;
Effect value calculating means for calculating a saving effect value obtained by integrating the saving amount;
Display means for displaying the saving effect value;
An arc welding apparatus comprising:   When the gas saving amount characteristic table corresponding to the measured gas OFF interval time does not exist, the selecting means interpolates a plurality of existing gas saving amount characteristic tables to obtain a new gas saving amount characteristic table. The arc welding apparatus according to claim 1, wherein the arc welding apparatus is created and selected.   3. The arc welding apparatus according to claim 2, wherein the gas flow rate control means is a mass flow controller that outputs, stops, and adjusts the flow rate of the shielding gas by an external signal input.   4. The arc welding apparatus according to claim 1, wherein the saving effect value includes a reduction amount obtained by multiplying an integrated value of the saving amount by a predetermined gas unit price. 5.   The arc welding apparatus according to claim 4, wherein the gas unit price can be changed by a teach pendant for creating the teaching data.

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