JPH11314156A - Device for monitoring feeding of welding wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect welding stage in case of changing the wire feeding speed, to quicken the repairing and the adjusting of a welding device and to improve the welded quality by detecting the wire feeding speed with a prescribed interval at the time of automatically welding and displaying each detected feeding speed on the different displaying part in order. SOLUTION: The number of revolutions of a rotary roller 61 in a feeding speed detecting instrument 6 rotated while contacting with the welding wire 51 fed to a welding torch 1 is converted into a pulse signal with a rotary encorder 81, and this signal is counted with a counter 82 and inputted to a welding wire feeding monitoring device 8. This monitoring device 8 is connected with a torch panel 83 having both functions of data setting and displaying and the compared result between the inputted wire feeding speed and the target speed, is stored and on the other hand, at the time of varying such wire feeding speed as to exceed the permissible range of the target speed, the abnormality is displayed. Further, since even the small variation as an omen of the large variation of the feeding speed, can be detected with a wire feeding speed monitor, after completing the welding, the preparation for the repairing and the adjusting of the welding device can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding wire feed monitoring device for monitoring whether or not feeding of a welding wire is normally performed in automatic arc welding.

[0002]

2. Description of the Related Art When automatic arc welding is performed using an industrial robot or the like, particularly when a constant voltage welding power source is used, the feeding speed of a welding wire to a welding torch is set to a predetermined constant speed. Need to be managed. The welding wire is usually pulled out of a wire pack or the like by a feed roller driven at a constant speed by a motor, and sent to the welding torch through a conduit tube or the like.

In this case, the feed roller is rotated at a constant speed, but the feed speed of the welding wire often fluctuates due to slippage of the roller, friction in the conduit tube, and the like. If the amount of the change is excessive, a defect occurs in the welded portion.

Therefore, for example, Japanese Patent Application Laid-Open No. 57-184581
In the publication, a means for detecting a feed speed of a welding wire is provided, and when the wire feed speed is greatly deviated from a target speed, a motor (that is, a feed roller) is stopped, and a welding wire feed control device is provided. Has been proposed.

[0005]

In the above-described conventional apparatus, the feed roller is only stopped when the wire feed speed fluctuates greatly. However, a large change in the feed speed of the welding wire occurs suddenly. Is small, and small fluctuations in the feed rate frequently occur as a precursor. Also, knowing at which stage in the welding process a large variation in the feed rate has occurred is useful for subsequent repair adjustments of the welding equipment.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a welding wire feed monitoring device capable of monitoring a feed speed of a welding wire at each stage of a welding process. I do.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a wire feeding means (7) for feeding a welding wire (51) and a feeding speed of the welding wire (51) are reduced. A feed speed detecting means (6) for detecting at predetermined intervals and a display means (83) for sequentially displaying each feed speed detected at predetermined intervals on different display units are provided. In the first aspect of the invention, when the feeding of the welding wire is started during the welding operation, the feeding speed of the welding wire is detected at predetermined intervals, and these feeding speeds are sequentially displayed on different display units of the display means. . Therefore, it is possible to monitor the feed speed of the welding wire at each stage of the welding process, and it is possible to reliably monitor a small change in the feed speed as a precursor to a large change in the feed speed of the welding wire. . In addition, since it is possible to know at which stage in the welding process a large change in the feed rate has occurred, it is useful for repair adjustment of the welding device thereafter.

In the second invention, the feed speed detecting means (6) includes a rotating roller (61) that contacts the welding wire (51) and rotates according to the movement of the welding wire, and the rotating roller (61). 61) a rotary encoder (81) connected to the rotary encoder for rotating and outputting a pulse signal according to the rotation amount
Means (82, 84, step 1) for counting the pulse signals within a predetermined time and calculating the feeding speed based on the counted pulse signals.
06). In the second invention, the movement of the welding wire is converted into the rotation of the rotary roller, and the pulse signal from the rotary encoder connected to the rotary roller within a predetermined time is counted, whereby the wire feeding speed is accurately calculated. Is done.

According to the third aspect of the present invention, there is further provided a comparing means (84, step 107) for comparing each of the above-mentioned feeding speeds with the target speed, and a display means (83) in addition to the above-mentioned respective feeding speeds. It is set to display the comparison result. In the third aspect, in addition to the feed speed of the welding wire at each stage of the welding process, it is possible to easily monitor how much the feed speed fluctuates from the target speed.

[0010] The reference numerals in parentheses indicate the correspondence with specific means described in the embodiment described later.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall construction of an automatic robotic welding apparatus provided with a welding wire feed monitoring device (hereinafter simply referred to as a monitoring device) 8. In the figure, welding torch 1
Is supported by the arm 21 of the industrial robot 2, and the industrial robot 2 moves the welding torch 1 at the tip of the arm 21 along the required portion of the workpiece B in accordance with an output signal from the robot controller 3. . The moving locus and moving speed of the robot arm 21 are stored in advance in the robot controller 3 by the teaching panel 31. At this time, the designation of each welding portion on the moving locus and the welding conditions for each welding portion are also stored. Let me do. The welding conditions are, for example, welding current, welding voltage (arc voltage), wire feeding speed (target speed), feeding time (welding time), and the like. The arc welding power source 4 having constant voltage characteristics as in the present embodiment is used. in case of,
A constant wire target speed is set for each welding site.

The welding wire 51 housed in the wire pack 5 in a pail is passed through the flexible conduit tube 52 to the welding torch 1, and on the way, the rotating roller 61 and the pressing roller 62 of the feed speed detecting device 6. And feed rollers 71 of the wire feed device 7
And the pressure roller 72. Feed roller 71
Is driven by a motor (not shown) that is rotated at a constant speed by an output signal from the arc welding power supply 4, and the welding wire 51 is pulled out of the wire pack 5 by the feed roller 71 and is welded at a predetermined speed. 1
From the tip of the workpiece to the workpiece B.

When a welding signal 3a is output from the robot controller 3, the arc welding power source 4 applies a voltage between the welding torch 1 and the workpiece B, so that the tip of the welding wire 51 and the workpiece B are connected to each other. During this time, an arc discharge is generated to perform welding, and the feed roller 71 is activated to start feeding the welding wire 51. The arc current and the arc voltage are detected by the ammeter 41 and the voltmeter 42, respectively, and output to the monitoring device 8.

The detailed structure of the feeding speed detecting device 6 is shown in FIGS. The rotating roller 61 is fixed to a shaft 64 rotatably supported on a substrate 65 by a ball bearing 63. Two guide grooves 611 and 612 having different sizes are formed in parallel on the outer periphery of the rotating roller 61. Have been.
The pressure roller 62 is rotatably supported by a shaft 67 via a ball bearing 66.
5 and is provided upright at the tip of a leaf spring body 68 bent in an L-shape. The pressure roller 62 is urged toward the outer periphery of the rotating roller 61 by the spring force of the leaf spring body 68. The welding wire 51 is exposed between the male and female conduit tube connection fittings 651 and 652 provided on the left and right ends (FIG. 2) of the substrate 65, respectively, and any one of the outer circumferences of the rotary roller 61 according to its outer diameter. It is passed through the guide grooves 611 and 612 (FIG. 3) and is held by the pressure roller 62 in this state. Welding wire 51 by feed roller 71
Is moved, the rotating roller 61 is moved in accordance with the movement.
Rotates.

At the back of the board 65, a pedestal 69 is assembled by bolting a plate material, and a rotary encoder (hereinafter, referred to as an encoder) 81 is attached to the pedestal 69. The input shaft 811 of the encoder 81 is the shaft 6
4 and are connected by a coupling 641. When the rotation roller 61 rotates, the shaft body 64 and the input shaft 811 of the encoder 81 integrally coupled thereto rotate, and a pulse signal corresponding to the rotation amount (that is, corresponding to the movement amount of the welding wire 51) is generated by the encoder 8.
1 is output. The pulse signal from the encoder 81 is input to the counter 82 and counted as shown in FIG. 1, and the count value is input to the monitoring device 8. In this embodiment, an encoder 81 having a pulse rate of 1000 pulses / rotation is used, and the welding wire 51 is set to 0.109.
One pulse is output every mm movement. The monitoring device 8 receives a welding signal 3a and a robot activation signal 3b from the robot control device 3. The robot activation signal 3b is at “H” level from the start to the end of the welding operation by the industrial robot 2. The welding signal 3a is output every time the welding torch 1 reaches each welding site, and is at the “H” level from the start to the end of welding at each welding site.

The monitoring device 8 is connected to a touch panel 83 having both data setting and display functions. The monitoring device 8 has a built-in microcomputer having a CPU, a memory such as a ROM and a RAM, and has an arithmetic unit 84 and a panel interface unit 85 by software.
Has been realized. The calculation unit 84 calculates the feed speed of the welding wire 51 at each welding stage for each welding site from a change in the count value of the counter 82 as described later. The panel interface unit 85 stores data input from the touch panel 83 in a memory as described later, or displays the data stored in the memory on the touch panel 83.

Hereinafter, the operation of the arithmetic unit 84 of the monitoring device 8 will be described.
A description will be given based on the flowchart of FIG. 4 with reference to the signal time chart of FIG. In step 101 of FIG.
The robot activation signal 3b from the robot controller 3 (FIG. 5)
When (A)) is input, it is checked in step 102 whether the welding signal 3a (FIG. 5B) from the robot controller 3 has risen to the "H" level. If the welding signal 3a rises and the detection output of the ammeter 41 and the voltmeter 42 at this time indicates a normal value at the time of welding, it is determined that welding at a new welding site has been started.
Go to 03. The welding signal 3a is, as shown in FIG.
The level rises to the “H” level each time the welding site [1], [2], [3] is reached, and the welding site [1], [2], [3]
At the end of the welding at the point "L".

In step 103, after an initial delay of a fixed time T0 from the rise of the welding signal 3a, step 10
Proceed to 4 to perform pulse counting. The reason for performing the initial delay is that even if the feed roller 71 is activated at the start of welding, there is a certain delay before the feed speed of the welding wire 51 becomes a steady state, and the time T0 is 0.2 seconds to 5 seconds. The change can be set from the touch panel 83 within the range. If the welding signal is not rising at step 102, it is checked at step 110 whether or not the welding signal 3a is at "H" level. If it is at "H" level, the process immediately proceeds to step 104.

In step 104, pulse signals output from the encoder 81 (FIG. 1) are counted. The actual counting is performed by the external counter 82 (FIG. 1) as described above.
Is obtained from the change in the count value of the counter 82 until the time is up (step 105).
The time T1 at this time is, for example, 1 second, and another time (for example, 2 seconds) can be selected on the touch panel 83.
If the time-up is confirmed in step 105, the feeding speed (mm / min) of the welding wire 51 is calculated from the pulse number in step 106, and in step 107, the calculated wire feeding speed is calculated. And the target speed at. The target speed is set in advance for each welding site by the touch panel 83 and stored in the memory.

In step 108, the calculated wire feeding speed and the result of comparison between the calculated wire feeding speed and the target speed are stored in a memory. The comparison result is, for example, an abnormality (NG) when the wire feeding speed fluctuates beyond the allowable range of ± 10% of the target speed. Another value (for example, ± 5%) can be selected in advance for the allowable range by the touch panel 83. In step 109, it is confirmed that the time has been increased by a predetermined time T2. The time T2 is, for example, 1 second, which is the same as the time T1. When the time T2 has expired, the processing from step 102 onward is performed again. By the operation of the arithmetic unit 84, as shown in FIG. 5C, after a certain delay time T0 from the start of welding at a certain welding site (in the figure, an example of the welding site [1] is shown), Time T
The pulse count is performed within 1 and the feeding speed of the welding wire 51 is calculated within the subsequent time T2, and these are alternately continued.

As a result, each stage (1), (2), (3),..., (N−1),
The wire feeding speed in (n) is calculated and sequentially stored in the memory, and each stage (1), (2), (3),
.., (N-1), and the comparison result with the target speed in (n) are simultaneously stored. When the welding signal 3a falls to the "L" level during the pulse counting as in the step (n + 1) (that is, when the welding operation at the welding portion [1] is completed), the step (n + 1) is performed. The calculation of the wire feeding speed in is not performed as invalid. The calculation of the wire feed speed for each fixed time (T1 + T2) is performed in the same manner for the other welding parts [2] and [3].

Panel interface unit 8 of monitoring device 8
5, a “select vehicle type” screen as shown in FIG. 6 is displayed on the touch panel 83 prior to activating the industrial robot 2. In the present embodiment, ten types of vehicles from A to J can be selected by touching the selection areas “1” to “10”. It is needless to say that the number of vehicle types can be increased or decreased according to the memory capacity.

FIG. 7 shows a “site-specific wire feed monitor” screen for vehicle type “4” displayed on touch panel 83. The feeding speed can be set for 15 welding sites on the two screens of FIGS. 7A and 7B. In the case where there are only three welding parts as in the present embodiment (see FIG. 5B), as shown in FIG. Set the corresponding wire usage. Such setting of the wire feeding speed or the wire usage is performed by calling a “wire feeding data setting” screen or the like shown in FIG.

FIG. 7A "Wire feed monitor for each part"
The numerical value displayed in the column of “Measurement / Judgment” of “Feeding speed” on the screen is the final welding stage at each welding site (FIG. 5 (C)).
In step (n)) and stored in the memory. In addition, the judgment of NG at the welding portion of the number "2" means that at least one welding stage (one of the stages (1) to (n) in FIG. 5C) at the welding portion.
Indicates that the wire feeding speed fluctuated beyond the allowable range of ± 10% of the target speed.

FIGS. 9A to 9C show the wire feeding speed calculated and stored in each of the welding stages (1) to (n) at each of the welding portions [1] to [3]. Call the three "wire feed speed monitor" screens shown. FIG. 9 shows the case of the welding location "3" of the vehicle type "4", and the feed speed set value (target speed) is "6900". The figure shows the case where there are only three welding stages ((n) = (3) in FIG. 5C), and the wire feed calculated at each stage of “1” to “3” and stored in the memory. The feed rate is displayed. On the “wire feed speed monitor” screen shown in FIG. 9, 63 (ie, (n) = (63) = 2 (seconds) × 63 =
126 (seconds)) at each welding stage.

As described above, during the welding operation by the industrial robot 2, the wire feeding calculated and stored by the arithmetic unit 84 of the monitoring device 8 according to the procedure described above (FIG. 4) at each welding stage of each welding portion. The speed can be checked on the “wire feed speed monitor” screen after the welding operation is completed. This makes it possible to foresee in advance a small change in the wire feed speed as a precursor to a large change in the feed speed of the welding wire 51, and to set a wire feed speed exceeding an allowable range with respect to the target speed. Knowing at what stage during the welding process the large fluctuations in the welding process can be used to assist in subsequent repair adjustments of the welding equipment. The numerical value displayed in the column of “measurement / judgment” of the “wire usage” on the “wire feed monitor for each part” screen (FIG. 7) corresponds to the welding speed calculated for each welding stage. Obtained by multiplying time. In this case, even when the measured value of the “wire usage” fluctuates beyond the allowable range with respect to the set value (target usage), an abnormality determination is made and “NG” is displayed.

Although the above embodiment has been described with reference to the case where the number of welding portions is three, the number of welding portions is not limited to a plurality.
It may be singular. If the feed speed of the welding wire fluctuates excessively, not only is “NG” displayed, but also an abnormal signal is output from the monitoring device to the robot control device to stop the operation of the industrial robot. Alternatively, measures such as shutting off the arc welding power source may be taken.
Furthermore, if possible, it is better to install the feed speed detecting device 6 between the wire feeding device 7 and the welding torch 1. This is because a value closer to the actual welding wire speed in the arc welded portion can be detected.

[0028]

As described above, according to the welding wire feeding monitoring device of the present invention, the feeding speed of the welding wire at each stage of the welding process can be monitored.

[Brief description of the drawings]

FIG. 1 is a view showing an overall configuration of a robot automatic welding device provided with a welding wire supply monitoring device.

FIG. 2 is an overall front view of the wire speed detecting device.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a processing flowchart of a calculation unit.

FIG. 5 is a signal time chart.

FIG. 6 is a front view of a touch panel display screen.

FIG. 7 is a front view of a touch panel display screen.

FIG. 8 is a front view of a touch panel display screen.

FIG. 9 is a front view of a touch panel display screen.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Welding torch, 4 ... Arc welding power supply, 5 ... Wire pack, 51 ... Welding wire, 6 ... Feed speed detection device, 61 ...
Rotary roller, 7: wire feeding device, 8: welding wire feeding monitoring device, 81: rotary encoder, 82: counter, 83: touch panel, 84: arithmetic unit, 85: panel interface unit.

Continued on the front page (72) Inventor Takuo Chimura

Claims (3)

[Claims] 1. A wire feeding means for feeding a welding wire, a feeding speed detecting means for detecting a feeding speed of a welding wire at a predetermined interval, and different display units for each feeding speed detected at a predetermined interval. And a display means for sequentially displaying the welding wire feed monitoring device. 2. The method according to claim 1, wherein the feed speed detecting unit includes: a rotating roller that contacts the welding wire and rotates according to the movement of the welding wire; 2. The welding wire feed monitoring device according to claim 1, comprising a rotary encoder that outputs a signal, and a unit that counts the pulse signal within a predetermined time and calculates a feed speed based on the count. 3. A comparison means for comparing each of the feeding speeds with a target speed, wherein the display means is set to display each comparison result by the comparing means in addition to the respective feeding speeds. The welding wire feeding monitoring device according to claim 1 or 2.