JP2865580B2 - Diagnosis method for laser beam welding apparatus and its apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for diagnosing a laser beam welding apparatus and an apparatus therefor.

[0002]

2. Description of the Related Art A conventional laser beam welding apparatus is shown in FIGS. 2 and 3, in which there are inlet and outlet clamp apparatuses 2 and 3 which are provided on a common base 1 at a predetermined interval. , A shear device 4 capable of moving back and forth between the entrance and exit clamping devices 2 and 3 from the left and right, and a back bar capable of moving forward and backward between the entrance and exit clamping devices 2 and 3 in the same manner. There is a device 5. Further, an upper head 6 attached to the upper part of the outlet clamp device 3,
And a welding carriage device 7, 8 for moving the machining head 9 on the upper head 6 in the left-right direction, that is, in the direction of the end face of the preceding strip 12 and the following strip 13 and in the incoming and outgoing directions, and vertically between both strip end faces. Install,
A transmission tube 10 for transmitting a laser beam oscillated by a laser oscillator 11 is provided. Here, arrow A is the following strip
13 shows the direction of movement. FIG. 4 shows an optical system of the above-mentioned conventional laser beam welding apparatus, which comprises a reflecting mirror 14 for changing an optical path of a laser beam 16 and a condenser lens 15 built in the processing head 9.

Next, the operation of this conventional device will be described. In the steelmaking process line, when continuous processing such as pickling, plating, and heat treatment of the strip is performed, the strip travels in the direction indicated by arrow A in FIG. When the strip is sent and reaches the end, the preceding strip 12 is moved to the shear device 4 as shown in FIG.
And is stopped within the blade width 4a. In this state,
The trailing strip 13 has its tip end set to the blade width 4 of the shear device 4.
It is sent into a and stops. 2 and FIG.
The back bar device 5 is retracted as shown in FIG.
Moves forward and is located between the entrance-side clamp device 2 and the exit-side clamp device 3.

Then, after the leading and trailing strips 12, 13 are clamped by the two clamping devices 2, 3, the shearing device 4,
The upper shear blade descends to cut the opposing ends of both strips 12,13. Subsequently, as shown in FIGS. 3 and 6, the shear device 4 is retracted, the back bar device 5 moves forward and is positioned between the entrance-side clamp device 2 and the exit-side clamp device 3, and then the entrance-side clamp device The leading strip 12 is moved to the exit side clamping device 3 by a predetermined amount, and the cut surfaces of the preceding strip 12 and the following strip 13 are butted so that the root gap of the abutting portion becomes a predetermined amount.

Next, the butted strips 12, 13
The welding carriage devices 7 and 8 are moved and set in the entry and exit directions, that is, at right angles to the end faces of the strips 12 and 13 so that the machining head 9 comes to the abutting portion. After preparing for welding in this way, the transmission pipe 10
The laser beam 16 oscillated by the laser oscillator 11 is changed in direction by the reflection mirror 14 and the condensing lens
The welding is started by focusing the light on the abutting portion of both strips by 15. At the same time, the two strips 12, 13 are continuously welded by moving the welding carriage device 7 in the left-right direction, that is, in the direction of the end faces of the strips 12, 13.

[0006]

However, in the above-mentioned conventional laser beam welding apparatus, poor welding occurs in butt welding. The causes are as follows. When the actual values, such as the laser output and the running speed of the processing head, deviate from the set values. Changes in mechanical accuracy of the inlet / outlet clamp device, shear device, back bar device, etc., or oil leaks from the actuator.

[0007] As a countermeasure, various methods of determining and diagnosing abnormalities such as the laser output and the traveling speed of the processing head have been proposed, mainly by monitoring the abnormalities. However, at present, there is no appropriate countermeasure against changes in machine accuracy, etc., and the operating process line is stopped each time, the equipment is disassembled, detailed inspection and measurement is performed, and defective parts are repaired. This is the actual situation.

[0008] Therefore, if welding defects due to abnormal factors are not detected, the welded strip may meander in the process line or break from the weld, and the process line must be stopped for a long time. , If the abnormal condition occurs for a long time,
Operational losses will be severe. Therefore, in order to solve the above-mentioned problems, (a) it is necessary to obtain information for each continuous welding, (b) it is necessary to clarify the factors that cause the difference in the amount of butting, (c) Investigations are needed to accurately detect the difference in the butted amount, and (d) clarify the relationship between the change in the butted amount and the quality of the weld.

Among the above, methods for elucidating or monitoring (a), (b) and (d) have already been established, but methods for accurately detecting the difference in the amount of abutting in (c) have been established. Therefore, even if an abnormality occurs in the apparatus, it is not possible to detect the abnormality at an early stage and take an immediate response. The present invention has been proposed to solve the problems of the prior art as described above,
It is an object of the present invention to provide a method of diagnosing a laser beam welding apparatus capable of determining the presence or absence of a change in the position of an entrance-side clamp apparatus and an exit-side clamp apparatus, and an apparatus thereof.

[0010]

The present invention SUMMARY OF THE INVENTION may, leading strip tail end and the leading end of the trailing strip and against after cutting, while clamped respectively between the outlet side clamp device and the inlet side clamp device laser A method for diagnosing the presence or absence of a mechanical error between the entrance-side clamping device and the exit-side clamping device when welding with a beam welding device, comprising the steps of: Measure the amount of movement in the direction perpendicular, compare the butted amount converted from the measured value with a predetermined butted amount, and determine whether the entrance clamp device has stopped at a predetermined position. Diagnosing, and measuring a position where the entrance-side clamp device retreats in a direction opposite to the traveling direction of the strip and waits, and retreats the entrance-side clamp device. Diagnosing the presence or absence of a change in the position, and measuring the position where the entrance-side clamp device advances in the same direction as the strip traveling direction and stops at the welding point to determine whether or not the advancement position of the entrance-side clamp device has changed. Diagnosing
A step of measuring a fixed position of the outlet clamp device and diagnosing a change in the position of the outlet clamp device.

Further, the present invention is, against after cutting the previous end of the leading strip tail end and trailing strips,
A device for diagnosing the presence or absence of a mechanical error between the entrance-side clamp device and the exit-side clamp device when welding with a laser beam welding device while clamping with the exit-side clamp device and the entrance-side clamp device, respectively. A contact displacement meter provided so as to freely contact the end of one taper wedge that determines the advance position of the device, and contacts provided so as to freely contact contact plates attached to four places around the entrance side clamping device. A displacement type displacement meter, a plurality of contact type displacement meters that are provided so as to be able to abut around the output side clamp device, a dynamic strain meter that converts a measurement signal of each of the contact type displacement meters into an electric signal, A computer for inputting an electric signal of a strain gauge and diagnosing a change in the position of the inlet-side clamp device and the outlet-side clamp device during the welding operation. A diagnostic device Zabimu welding device.

[0012]

According to the present invention, a plurality of contact displacement gauges are mounted on the inlet and outlet clamp devices to diagnose the presence or absence of a change in the position of each of the trailing end and the leading end of the preceding strip during welding. Therefore, if a displacement occurs in the entrance-side clamp device and / or the exit-side clamp device, it is possible to quickly detect the displacement. As a result, the accuracy of butting of the leading and trailing strips can be improved, so that the meandering of the strips and the breakage of the welded portion can be prevented.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment of the present invention. Note that the same members as those in the conventional example in the drawing include:
The same reference numerals are given and the description is omitted. In the figure, reference numeral 17 denotes a taper wedge for determining the advance position of the entrance-side clamp device 2, and reference numerals 18b to 18e denote contact plates attached to the front and rear surfaces of the entrance-side clamp device 2. Reference numerals 19a to 19g denote contact-type displacement gages having built-in strain gauges, which are fixed by mounting jigs 20a to 20g such as a stand with a magnet, for example.
Reference numerals 21a to 21g denote dynamic strain gages which are connected to contact type displacement gages 19a to 19g via signal lines 22a to 22g.
It has a function of converting a signal detected by a to 19g into an electric signal. Reference numeral 23 denotes a computer which is connected to dynamic strain meters 21a to 21g via signal lines 24a to 24g.
The electric signals converted by the signals a to 21g are input and arithmetic processing described later is performed.

First, the amount of movement of the taper wedge 17 attached to the entry-side clamp device 2 in the direction of arrow B is measured by the contact displacement meter 19a, and converted into an electric signal by the dynamic strain meter 21a via the signal cable 22a. Then, the signal is transmitted to the computer 23 via the signal cable 24a. Accordingly, the computer 23 compares the predetermined butting amount set in advance with the converted butting amount calculated from the moving amount of the taper wedge 17 measured by the contact displacement meter 19a, thereby making the entrance-side clamping device 2 Can be diagnosed whether the vehicle has moved forward to a predetermined position and stopped as set.

Next, the entrance-side clamp device 2 is moved to the retreat position 2.
a (at the position indicated by the dashed-dotted line moved to the right with respect to the diagram of arrow C in the drawing), the contact type displacement gauges 19b, 19c contact the contact plates 18b, 18c. Thus, the retracted position 2a of the entrance-side clamp device 2 is measured, converted into electric signals by the dynamic strain gauges 21b, 21c via the signal cables 22b, 22c, and transmitted to the computer 23 via the signal cables 24b, 24c. . Thereby, the change of the retraction position 2a of the entrance-side clamp device 2 at the time when the entrance-side clamp device 2 is waiting at the retraction position 2a can be constantly diagnosed.

Next, the entrance side clamp device 2 is moved to the forward position 2.
b (the position indicated by the solid line moved to the left with respect to the drawing of arrow C in the drawing) at the point of time
When the d and 19e come into contact with the contact plates 18d and 18e, the advance position 2b of the entrance-side clamp device 2 is measured and converted into electric signals by the dynamic strain gauges 21d and 21e via the signal cables 22d and 22e. , Computer 23 via signal cables 24d, 24e
To be transmitted. Thereby, the change of the advance position 2b of the entrance-side clamp device 2 at the time when the entrance-side clamp device 2 is moving to the advance position 2b (during butt welding) can be constantly diagnosed.

Next, the position of the outlet clamp device 3 is measured by contact-type displacement meters 19f and 19g attached at two places around the outlet clamp device 3 so as to always contact the outlet clamp device 3. Then, the signals are converted into electric signals by the dynamic strain gauges 21f and 21g via the signal cables 22f and 22g, and transmitted to the computer 23 via the signal cables 24f and 24g. Thereby, the position of the exit side clamp device 3 can be diagnosed during the operation of the laser beam welding device.

Hereinafter, an example in which the apparatus of the present invention configured as described above is applied will be described. For the contact type displacement meter 19a, a measurement type with a measurement length of 25 mm is applied.
For 19 g, a measurement length of 10 mm was used. The measurement range of the dynamic strain gauges 21a to 21g is 0 to 25mm and 0 to 10mm.
The specification is such that a DC signal of 0 to 5 V is output for any of mm.

First, the taper wedge 17 moves in the direction of the arrow B in FIG. 1 in order to position the advance position 2b of the entrance-side clamp device 2, but the leading and trailing strips 12 and 13 for laser beam welding. Command value RG _SV and the taper wedge 17
Has the following relationship with the movement amount L _W of L _W = RG _SV / T _P (1) where T _P represents the slope of the inclined surface of the tapered wedge 17.

In this embodiment, the root gap command value R
G_SVAnd the movement L of the taper wedge 17 _WI understand the relationship
For the sake of simplicity, the following (2)
According to the formula, the actual movement amount L of the taper wedge 17_WRRootgi
Cap conversion value RG_RVCalculate the root gap command value
RG_SVAnd route gap conversion value RG_RVCompare and diagnose
Was.

RG _RV = L _WR · T _P (2) FIG. 7 shows this measured value, in which the horizontal axis in the figure is the root gap command value RG _SV , and the vertical axis is the vertical axis. The root gap conversion value RG _RV is taken. The solid line in this figure is RG _SV
= RG _RV , and a white circle indicates a measured value. The two dashed lines above and below the solid line in the figure indicate the allowable range of the variation of the root gap converted value RG _RV with respect to the root gap command value RG _SV .
As in this measurement example, whether the taper wedge 17 is operating as instructed can be quantitatively determined by this diagnosis.

FIG. 8 shows the measured values of the forward-moving position 2b of the entrance-side clamp device 2. As shown in FIG. This measurement is performed by the contact type displacement meters 19d and 19 arranged around the entry side clamp device 2.
e. The horizontal axis in this figure indicates the measurement order of the measured data signals, and the vertical axis indicates the difference between the actual value of the forward position 2b and the command value of the forward position 2b in the entrance-side clamp device 2. The reference position in the figure indicates the position of the actual value = command value of the forward position 2b, the white circle ○ indicates the operation side (WS) of the entrance-side clamp device 2, and the square □ indicates the drive side (DS). ) Indicates the measured value.
In this case, the upper and lower limits of the permissible value of the difference in the difference between the actual value of the forward position of the entry-side clamp device 2 and the command value are indicated by dashed lines. As shown in this measurement example, the difference between the actual value and the command value of the forward position of the entrance-side clamp device 2 is analyzed by a trend graph for each welding, so that the entrance-side clamp device 2 is analyzed.
It is possible to quantitatively diagnose the mechanical accuracy of the first and second strips 12, 12 at the time of welding by simultaneously analyzing the difference between the actual value and the command value of the forward position of the drive side and the drive value of the input side clamping device 2. It is possible to diagnose a change in thirteen butting amounts.

Next, FIG. 9 shows an example of measurement of the retracted position 2a of the entrance-side clamp device 2. This measurement is performed by contact-type displacement meters 19b and 19 disposed around the entrance-side clamp device 2.
c. The horizontal axis in this figure shows the numerical order of the data for each welding, and the vertical axis shows the input side clamping device 2.
Shows the measured value of the retreat position 2a. The alternate long and short dash line in the drawing indicates the permissible range of variation in the retreat position 2a of the entry-side clamp device. The retracted position 2a of the entrance-side clamp device 2 has a mechanical structure such that the entrance-side clamp device 2 is always at the same position when the entrance-side clamp device 2 is retreating. If the retreat position 2a changes during the retreat operation, the cutting position (moving direction of the strip) changes when the leading and trailing strips 12 and 13 are cut by the shear device 4, so that the butting amount at the time of welding changes. The measurement of the retreat position 2a of the entrance-side clamp device 2 is also one of the important management points. As shown in the measurement example of FIG. 9, by measuring the retreat position 2 a of the entry-side clamp device 2, it is possible to quantitatively diagnose the mechanical accuracy in the same manner as in FIG. 8.

Next, FIG. 10 will be described. This figure 10
The output side clamp device 3 is always fixed and its position does not change.
This is a measurement example in a case where the output side clamp device 3 may be elastically deformed at the time of cutting or welding of 2, 13 and the occurrence of a change in the amount of butting at the time of the preceding and succeeding strips 12, 13 or the welding by the shear device 4. The horizontal axis and the vertical axis in the figure are the same as those in FIG. As shown in the measurement example of FIG. 10, by measuring the position of the outlet clamp device 3, the mechanical accuracy of the outlet clamp device 3 can be diagnosed.

[0025]

As described above, according to the present invention,
A plurality of contact displacement gauges were attached to the inlet and outlet clamp devices to diagnose the position change during welding of the tail end and the front end of the leading and trailing strips. If a displacement occurs in the clamp device and / or the output side clamp device, it is possible to quickly detect the misalignment, so that a sign indicating a device abnormality can be detected at an early stage. This can significantly reduce the occurrence of strip meandering and breakage of the weld. Also,
Operation stabilization can be achieved as a qualitative effect, which is excellent for reducing operating expenses.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a perspective view showing an operation state of a conventional laser beam welding position.

FIG. 3 is a perspective view showing an operation state of a conventional laser beam welding position.

FIG. 4 is an explanatory diagram of an optical path of a laser beam.

FIG. 5 is an explanatory diagram of an operation state of a conventional laser beam welding position.

FIG. 6 is an explanatory diagram of an operation state at a conventional laser beam welding position.

FIG. 7 is a characteristic diagram showing a relationship between a route gap command value and a route gap conversion value.

FIG. 8 is a characteristic diagram showing data of a difference between an actual value of the forward position of the entrance-side clamp device and a command value.

FIG. 9 is a characteristic diagram showing measurement data of the retracted position of the entrance-side clamp device.

FIG. 10 is a characteristic diagram showing measurement data of a retreat position of the output side clamp device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Common base 2 Incoming side clamp device 3 Outlet side clamp device 4 Shear device 5 Back bar device 6 Upper head 7,8 Welding carriage device 9 Processing head 10 Transmission tube 11 Laser oscillator 12 Leading strip 13 Trailing strip 14 Reflector mirror 15 Optical lens 16 Laser beam 17 Taper wedge 18 Contact plate 19 Contact displacement gauge 20 Mounting jig 21 Dynamic strain gauge 22, 24 Signal line 23 Computer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B23K 26/00-26/02 B21B 15/00 B23K 37/04

Claims (2)

(57) [Claims] 1. A butt after cutting a preceding end of the leading strip tail end and the trailing strip outlet side clamp device and the inlet side clamp device and at the time of welding by laser beam welding device with clamps respectively A method for diagnosing the presence or absence of a mechanical error between the entrance-side clamp device and the exit-side clamp device, comprising: Diagnosing whether or not the entrance-side clamp device has stopped at a predetermined position by comparing the butting amount converted from the measured value with a predetermined butting amount set in advance; The position where the side clamp device is retracted in the direction opposite to the traveling direction of the strip and waits is measured, and it is diagnosed whether or not the retracted position of the input side clamp device has changed. Measuring the position at which the entrance-side clamp device advances in the same direction as the traveling direction of the strip and stops at the welding point, and diagnosing the presence or absence of a change in the advance position of the entrance-side clamp device; Diagnosing a change in the position of the outlet clamp device by measuring a fixed position of the outlet clamp device, and diagnosing a change in the position of the outlet clamp device. 2. A butt after cutting a preceding end of the leading strip tail end and the trailing strip outlet side clamp device and the inlet side clamp device and at the time of welding by laser beam welding device with clamps respectively A device for diagnosing the presence or absence of a mechanical error between the entrance-side clamp device and the exit-side clamp device, comprising: a contact-type displacement provided so as to abut on an end of one tapered wedge that determines a forward position of the entrance-side clamp device. A contact type displacement meter provided so as to be able to come into contact with a contact plate attached to four places around the entrance side clamping device, and a plurality of contact type displacement meters provided so as to be able to contact around the exit side clamping device. A displacement gauge, a dynamic strain meter for converting measurement signals of these contact type displacement meters into electrical signals, and the input side clamp during welding operation by inputting the electrical signal of the dynamic strain meter. Diagnostic apparatus for a laser beam welding device comprising a computer for diagnosing the presence or absence of a change in position of the location and the outlet side clamp device, in that it consists of.