JPH01245973A - Oscillation type rotating arc welding method - Google Patents

Abstract

PURPOSE:To maintain bead height constant by setting the oscillation unit quantity from estimated groove width and making an initial oscillation width value to integral times of the oscillation unit quantity and detecting a corresponding value to the change of the groove width and varying an integer so as to maintain penetration constant with respect to the groove width change to control oscillation width. CONSTITUTION:A welding wire 5 is rotated and a torch 3 is oscillated in a groove 2. The arc voltage, etc., are detected and the groove is profiled and the position of the torch 3 is controlled so as to maintain the set arc voltage, etc., and arc welding is performed. The oscillation unit quantity is set from the estimated groove width and the initial oscillation value is made to the integral times of the oscillation unit quantity. The corresponding value to the change of the groove width is detected and the integer is varied so as to maintain the penetration constant with respect to the change of the groove width to control the oscillation width. When this controlled oscillation width, the oscillation width before its one cycle, the wire feed rate, the desired bead height, an initial value of the welding speed and the welding speed to be controlled are denoted by Ww, Wwo, Vfo, (h), Vo and V respectively, the welding speed is controlled based on a formula, V=Vfo/{(Vfo/Vo)+(Ww-Wwo) (h)}.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an oscillating rotary arc welding method that employs oscillation in rotating arc welding, and in particular, to an oscillating rotary arc welding method that can obtain an appropriate penetration width with respect to fluctuations in groove width. In addition to variable control of the swing width,
This invention relates to variable control of welding speed in order to compensate for the amount of welding due to variations in groove width and to keep the bead height constant.

[Prior Art] According to a high-speed rotating arc welding method in which an arc is rotated by rotating a welding wire at high speed around a rotation axis,
The physical effect of the arc is dispersed to the periphery, resulting in benefits such as dispersion of welding around the periphery, formation of flat beads (curved beads), and improvement of the wire melting rate due to rotational centrifugal force, especially in narrow grooves of thick plates. It is used to great effect in welding.

Further, this type of high-speed rotating arc welding method has a property that the arc voltage E' and welding current (2) change as the groove width changes.

The characteristics of changes in voltage E and welding current (2) will be explained below.

Fig. 9 is a side view of the tip of the rotating arc torch 3 and the groove 2 when performing high-speed rotating arc welding. The arc length, Cf, R, and L indicate the position of the wire 5 when rotating, Cf is the position of the wire 5 in front of the welding direction, R is 90 degrees to the right clockwise when facing the welding direction, and L is the welding direction. Wire 5 on the left counterclockwise when facing the
Indicates the location of Further, CW indicates the direction of rotation of the wire 5.

Fig. 1O is a diagram of the welded part shown in Fig. 9 viewed from the direction of the rotation axis O, where Cr is the position of the wire 5 at the rear with respect to the welding direction Z, and φ is the rotation of the wire 5 with respect to the welding direction Z. corner,
θ indicates the rotation angle when the position of the wire 5 coincides with the center line WC of the groove.

As shown in FIGS. 9 and 10, when the wire 5 rotates around the rotation axis 0 at a constant wire feeding speed, the wire 5 and the groove wall depend on the position of the wire 5 during rotation. The distance δ between them changes, and the arc length IL changes. Arc length 1. When this changes, the load characteristics change, and the welding current I and the voltage E between the electrode 1 and the groove (hereinafter referred to as arc voltage) also change.

The changes in the welding current 11 and the arc voltage E show changes based on a sine wave in accordance with the position of the wire 5. This is because when the wire 5 rotates, the distance δ changes depending on the position of the wire 5.
This is because it changes with a sine wave as a reference.

Note that this relationship holds true not only for consumable electrodes but also for non-consumable electrodes. Furthermore, this relationship holds true whether the groove shape to be welded is a V-shaped groove or a narrow-gap groove.

FIGS. 11(a) and 11(b) show the waveforms of the arc voltage E and welding current I, which change depending on the position of the rotating wire 5, that is, the arc. In the figure, (a) is the waveform of arc voltage E, and (b) is the welding current! , and each waveform has an upside-down shape.

Note that the waveform of the welding current ■ shown in Fig. 11(b) can be obtained only with a welding power source with constant voltage characteristics, and the arc voltage E
The waveform can be obtained with both constant voltage and constant current characteristic welding power sources.

In FIGS. 11(a) and 11(b), the waveforms shown by solid lines are generated when the center line WC of the groove and the rotation axis 0 are deviated by ΔX as shown in FIGS. 9 and 10. When the waveforms shown by broken lines are not shifted, that is, the position C of the wire 5 and the position Cr
This shows the case where the line connecting them coincides with the center line WC of the groove.

As shown by the broken lines in FIGS. 11(a) and 11(b), when the groove center line WC and the rotation axis 0 are not misaligned, the waveform is symmetrical about the position Ct of the wire 5. ,
If the rotation axis 0 is deviated from the center line WC of the groove, the waveform centered at the wire position Cf will be asymmetrical.

Note that by detecting and correcting this asymmetric waveform, the deviation amount ΔX in the X-axis direction can be corrected. That is, the waveform is divided left and right with respect to the welding direction centering on point C1, and each divided waveform is set at a constant angle φ from point Cf. The areas (integral values) SL and SR of the waveform created between this angle φ0 are obtained, and the welding torch is corrected in the X-axis direction so that the areas SL and SR are equal. can be made to coincide with the center line WC of the groove. This type of groove copying using the arc itself as a sensor is called groove copying using the arc sensor method.

[Problems to be Solved by the Invention] A swing welding method in which welding is performed while swinging (weaving) a welding torch in the width direction of the groove is known as a welding method for producing a wide bead. This type of oscillating welding method has not yet been introduced into the above-mentioned rotating arc welding method, and its introduction has been desired. (Hereinafter, the welding method in which the welding torch is weaved in the rotary arc welding method is referred to as the oscillating rotary arc welding method.) In realizing this oscillating rotary arc welding method, in order to make automatic welding unmanned, it is necessary to It is essential to automatically control the oscillation width in response to fluctuations in the groove width, which changes from moment to moment. This is because if the groove width changes, the required penetration width also changes.

Therefore, the main object of the present invention is to provide an oscillating rotary arc welding method that can obtain appropriate penetration by controlling the oscillating width with respect to fluctuations in the groove width.

In addition to this, it is also part of the object of the present invention to compensate for the amount of welding by controlling the welding speed according to the controlled oscillation width and to keep the bead height constant.

[Means for Solving the Problems] In order to achieve the above object, the oscillating rotary arc welding method of the present invention rotates a welding wire around its axis at a predetermined rotation radius at high speed, rotates the arc, and , The welding torch is reciprocated in the groove width direction within the groove, detects the arc voltage or welding current, and maintains a preset arc voltage or welding current while performing groove tracing using the arc sensor method. When performing arc welding while controlling the welding torch position in the height direction relative to the base material to be welded, the average value of the variation in the size of the predicted temple groove width in the groove width direction is set in advance by ±8. Then, set a mechanically controllable single position of rocking so that it is equal to this average value ± the absolute value of g |g| The initial value of the oscillation width to obtain the specified penetration is given as an integer multiple of the single oscillation position, and depending on the change characteristics of the arc voltage or welding current with respect to the change in the groove width size, it is determined that it does not correspond to the groove width change.・Detect the value of The swing width is controlled by increasing or decreasing the integer so that the value is maintained.

In addition, at this time, the controlled oscillation width is changed to Ww one cycle before the welding speed in order to compensate for the amount of welding and keep the bead height constant by controlling the welding speed according to the controlled oscillation width. When the oscillation width is W8°, the wire feeding speed is Vf0, the desired bead height is reached, and the welding speed to be controlled by VO% is the welding speed, the following formula, v=vro/(( vro/Vo)” (Ww-Wwo
) h) The welding speed is controlled based on h).

[Operation] According to the present invention, the empirically predicted average value ±g of the groove width change is set in advance, and the detection of the groove width change based on the change characteristics of the arc voltage or welding current is based on that value. 0, +g
, -g is assumed to be any of the discontinuous values.

Further, a mechanically controllable swing position is set to be equal to the absolute value 1 gl of the average value ±g, and the initial value of the swing width is given as an integral multiple of this swing single position. The oscillation width to be controlled is the detected value of the groove width change of 0. It is given by increasing or decreasing the above integer according to +g and -g.

In addition to the swing width control described above, changes in the amount of welding due to changes in the swing width are compensated for by controlling the welding speed in consideration of the wire feed amount.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

In addition, in the following explanation, we will use a constant current power source as the welding power source and explain the method of detecting the arc voltage, but if a constant voltage power source is used, it is sufficient to detect the welding current instead of the arc voltage. , which can be selected depending on the external characteristics of the welding power source.

FIG. 1 is an explanatory diagram showing the basic principle of the oscillating rotary arc welding method of the present invention, and shows the trajectory of the welding wire tip and the rotation axis.

In the figure, WR and WL are the turning points of the swing viewed from the rotation axis 0, WR is the right end of the swing, WL is the left end of the swing, and Ww is the swing width, that is, the right end of the swing WR to the swing end. This is the distance in the groove width direction between the left edges WL, and its center is the groove center line WC.

In addition, when indicating the wire rotation position in the following explanation, if it is necessary to specify the swing positions WR, WL, and WC of the rotation axis 0 at that time, the swing position symbol will be added to the rotation position symbol in parentheses. Indicated by (For example, R (□) indicates the rotating wire position R when the rotating axis 0 is at the right swing end WR.) In addition, e10.4 is the locus of the tip of the welding wire 5 due to rotation, and el" Let 'es be 2 cycles of oscillation.l
represents the locus drawn by the rotation axis 0 due to swinging.

When welding is started by generating an arc, the welding wire 5
rotates in the CW direction about the rotation axis 0, while rotating at a swinging speed vw about the rotation axis 0 in the width direction of the groove 2,
Welding direction Z at welding speed V while reciprocating with swing width Ww
Proceed to. As a result, a locus l of the rotation axis O is obtained.

In this case, the penetration width formed is determined by the size of the swing width WW, and the swing width WW for obtaining the necessary penetration width is determined according to the groove width G.

For example, the design value G0 of the groove width G (hereinafter referred to as the standard groove width G
Oscillation width Ww to obtain the necessary penetration width for 0)
is the reference swing width W0. This standard swing width W0 can be determined empirically depending on the size of the standard groove width G0. Now, if the groove width G changes by ΔG with respect to the reference groove width G0 and becomes G=GO+ΔG, the swing width Ww to be controlled is given by W w ” W o +ΔG (1).

Therefore, the swing width Ww to be controlled can be obtained by simply adding the groove width change ΔG to the reference swing width W0.

However, in actual control, it is difficult to accurately detect the magnitude of the groove width change ΔG, and since the swing width Ww is only about a few mm, it is difficult to accurately detect the magnitude of the groove width change ΔG. It is mechanically difficult to continuously adjust the swing width WW.

Therefore, in the present invention, when detecting the groove width change ΔG,
Average value of empirically predicted vine groove width variation ΔG±
g is set in advance. In this case, the actual groove width variation ΔG is detected as a value corresponding to the magnitude of the groove width variation ΔG based on the arc voltage change characteristics described in the above-mentioned prior art,
This detected value is compared with a set band consisting of ΔG=0. Select one of the three types: ΔG=+g− and ΔG=−g. In other words, groove width variation Δ
G is 0. It is assumed that either +g or -H is present.

In addition, the mechanically controllable swinging single position W unit is set equal to the absolute value 1gl of the predicted groove width variation ±g (Wuntt
= I g l ), and set the reference swing width W0
, the value W expressed as an integer multiple of this single swing position W u n I t is taken, and the swing width Ww to be controlled is determined by increasing or decreasing the above integer according to the discrimination value of the groove width variation ΔG. shall be given.

Here, the single swing position W unit is a controllable single position in the swing width direction determined by the accuracy of the motor that provides the swing, and if its value is given in advance, the swing speed Vw
[mm/sec] and arc rotation speed (wire rotation speed) N [Hz], WuoIt=vw・(1/
It can be expressed by the relational expression N)·m (2).

Note that m is the rotational speed of the arc that falls within the single swing position W unit, and is determined by the value of the single swing position W unit given in advance. That is, at the swing speed ■, the distance W un
lt is the number of revolutions of the arc during movement, m = Wun
tt/ (Vw ・(1/N) ) (3)
It can be expressed as However, m is appropriately processed, for example, rounded off to an integer.

In addition, the standard swing width W1/2 of the half cycle is set to the swing single position W.
If n times u n I t, that is, the reference swing width W, is expressed as 2n times the swing single position W u n l t, then
W 1 =2 n-W unit
It can be written as (4).

n is calculated from the empirically determined reference swing width WO.
(Wo / 2) / Wunlt=W, /2・Wu
It can be obtained as n,, (S). However, n shall be appropriately processed, for example, rounded off to an integer.

Also, since WunIt=1gI, the groove width variation ΔG
The swing width Ww when it is assumed that ΔG=±g is W w = 2 (n ±゛ through) ・Wu
It can be expressed as nlt (e).

Substituting the above equation (2) into equations (4) and (6), W+ = 2Vw' (1/N) ・m' n
(7) Ww=2Vw・(17N)・m・(n+
1) is obtained.

Equation (8) is a control equation that gives the swing width Ww to be controlled, and its initial value is expressed by equation (7). Whether +1 in the fourth term on the right side of equation (8) is positive or negative is determined by the determined groove width change ΔG. That is, +1 is taken when ΔG=+g, and -1 is taken when ΔG=-g. Furthermore, when it is assumed that ΔG=O, equation (7) is held.

Therefore, standard groove width GO, empirically determined standard swing width WO% predicted groove width variation ±g, swing single position W unit
, the swing speed Vw, and the rotational speed N of the arc are given, the magnitude of the groove width change ΔG is determined, and based on the determination result, (
The swing width Ww can be controlled according to equation 8).

In the above explanation, two types of values are used as the standard swing width: the empirically determined value WO% and the W given by equation (7), but the data obtained by the method of the present invention is not For example, it is sufficient to use only the empirically determined value W given by equation (7).

By the way, if the groove width G changes, the required amount of welding also changes, but in the present invention, the amount of welding is compensated by controlling the welding speed and the bead height is kept constant.

Welding speed control will be explained below with reference to FIG. This FIG. 2 is a side sectional view of the groove 2 shown in FIG. 1 above. In the figure, la indicates the base material surface, and 2b indicates the groove bottom surface.

First, in the above-mentioned swing type cycle, the swing width Ww has the following relationship with the groove width G at the wire position L (WLl, R(□) at both ends of the swing.

G=Ww+2△W (9) In this equation (9), △W is the rotation axis O at the swinging end.
This is the distance between G and the groove wall surface, and is basically a constant determined by the arc length and wire rotation diameter that should be set.If the set values of arc voltage and welding current are constant, the groove width G will fluctuate. is also constant. This has also been confirmed experimentally.

On the other hand, the wire feeding speed in one cycle of this oscillation is v
f, the welding speed is V, and the cross-sectional area of the deposited metal is A, then between these, V t = A ・V
There is the relationship (10).

Furthermore, if the vertical distance between the bead surface and the wire positions at both ends of the swing is △h, the bead height is h, and the groove angle is θ, then A = ((WW+ZΔW)-2△h-tanθ-h4anθ)
h. If the depth of the groove 2 (or the plate thickness of the base material 1) and the groove angle θ1 are constant, the amount of welded metal that always provides a constant beat height even under fluctuations in the groove width G can be adjusted. Area A
can be calculated based on the value of the swing width Ww obtained from the swing width control described above.

Therefore, if the groove angle θ, the desired bead height h, the wire feeding speed V, and the above constant ΔW are set in advance,
An appropriate welding speed V can be determined according to the value of the oscillation width Ww determined from the oscillation width control.

Next, a specific calculation for determining the welding speed V will be explained.

In general, welding speed■, welding current! , wire feeding speed V,
According to this general method, welding conditions such as , etc. are set in advance as initial values according to the groove shape, and thereafter the above-mentioned welding conditions are changed while monitoring the fluctuating state of the groove width. The initial values of wire feeding speed vf and welding speed V are each vf (1 + vO, welding is started under these conditions,
When one cycle of rocking is performed, the cross-sectional area A0 of the special deposited metal is Ao = v t-/vo
(12). Next, the swing width of one cycle of swing before reaching the swing width WW is Ww. shall be. At this time, for example, WW
Ww. (W w > W wo ).

In such a case, in order to ensure a constant bead height h, the weld cross-sectional area must be increased by ΔA = A - AO, that is, the above-mentioned A is expressed as (11)
In the formula, all other parameters except % WW are constants, so ΔA-A-AO = (Ww - Wwo) h (13
) Therefore, the welding speed V to ensure a constant bead height h is given by the following equation from equations (11) and (12).

V=V, 0/A = V to/ (A o +△A) = Vro/((Vr0/Vo)”(Ww-Ww0)h
} (14) Using this equation (14), if a desired bead height h is given in a groove with fluctuating groove width, the initial welding speed vo and wire feeding speed Vfo determined before welding can be The difference between the swing width WW and the swing width WWO of the previous cycle, that is, from WW WWO to the swing width W
The appropriate welding speed V at W is calculated. This method can be applied regardless of the set value as long as the groove angle θ1 is constant or does not change significantly, so it can be applied not only to the groove shape shown in FIG. 2 but also to asymmetric grooves.

FIG. 3 is a block diagram showing a control system for an oscillating rotary arc welding method according to a preferred embodiment of the present invention.

In the figure, a groove 2 is formed in a workpiece 1 to be welded, and a rotary arc torch (welding torch) 3 rotates a welding wire 5 in the direction of arrow CW by a motor 4 and uses a swinging arm 6 to widen the groove width. While weaving (swinging) in the direction, welding is carried out along the groove 2 in the direction perpendicular to the paper surface by feeding by the welding cart 7, and a weld bead (not shown) is produced behind it.
to form.

Further, the swinging of the swinging arm 6 is performed via a transmission mechanism 9 that converts the rotational motion of a swinging motor 8 capable of forward and reverse driving into linear motion.

In addition, as for the rocking method of the rotating arc torch 3, (a)
Keep the pitch P constant.

(b) Keep the swing speed Vw constant.

However, in order to keep the load on the swing motor 8 constant, (0) is selected here.

Further, the rotating arc torch 3 is supported by moving mechanisms 10x and toy in both the groove width direction (X-axis direction) and the height direction (Y-axis direction). x @ Mu assistance mechanism 10X, torch 3
The Y-axis moving mechanism 10Y is used to correct the position of the torch 3 in the Y-axis direction so that the arc length is always constant, that is, to perform groove tracing control. This is for long-term control.

Both of these moving mechanisms 10X and IOY are each driven by an X-axis motor tt.
Driven by x and y axis motor IIY.

Welding current and voltage are supplied to the torch 3 from a welding power source 12, which may be either a constant current power source or a constant voltage power source depending on the welding application, but here a constant current power source is used. An arc voltage detector 13 is connected in parallel to this welding power source 12. This detector 1
3E is provided as required for control, which will be described later.

Further, the wire feed motor 14 is controlled by a feed motor control device 15, the swing width by the swing arm 6 is controlled by a swing control device 16, and the welding speed by the welding cart 7 is controlled by the welding motor control device 15. This is done by the speed control device 17. Further, the X-axis motor IOX and Y-axis motor IOY are controlled by the X-axis control device tax and the y-axis control device 18Y.

Control commands to the feed motor control device 15, swing control device 16, and welding speed control device 17 are given from a main processing device 19 such as a microcomputer.
is an input device 2 for setting and inputting each constant and set value.
0 is attached, and furthermore, it receives the groove width change ΔG detection signal from the groove width detection device 21 and the wire rotation speed detection signal from the wire rotation speed detector 22 attached to the motor 4. It has become.

Next, the operation of the swing width control in the above embodiment will be explained with reference to the flowchart of FIG. 4. Note that the calculations in this flowchart are performed by the swing width calculation unit 192 in the main processing unit 19.

First, the reference swing width W0. which is determined empirically according to the reference groove width G0. Arc rotation speed N, swing speed vw.

and the rocking single position Wu determined according to the predicted groove width ±g.
The value of n is inputted from the input device 20 to the main processing device 19 and stored in the memory 191 (step SA).

Next, equations (3) and (5) are calculated, integer values of m and n are obtained, and these m and n are stored in the memory 191 (step SB), and the reference swing width given by equation (7) is W is calculated (step SC).

After the above calculations, welding is started (step SD).

Here, the arc rotation radial position at the start of welding is assumed to be e in FIG.

When 1.5 cycles of rocking are completed (step SE), the main processing device 17 either holds n in equation (7) based on the detection signal of the groove width change detection device 21, or
In the equation, the fourth term on the right side is determined whether to hold n+1 or n-1 (step SF), and the swing width Ww is calculated based on the determination result (step S
G).

Based on this, welding for one cycle of oscillation is performed (step SH).

Here, a judgment is made as to whether or not welding is complete (step S
l) Depending on the judgment result, welding is finished, or the operations from (step SF) to (step 31) described above are repeated until welding is completed.

Through such control, the swing width WW is controlled in response to fluctuations in the groove width G during welding, and an appropriate penetration width can be obtained regardless of fluctuations in the groove width G.

In addition, in (step SA) of the above description, the reference swing width W is determined empirically according to the reference groove width G0. However, if the data of Wl expressed by equation (7) is obtained in advance, then in step SA)
w, N, m, and n may be manually performed and (steps SB) to (steps SC) may be omitted.

Next, regarding the operation of welding speed control in the above embodiment, the fifth
This will be explained with reference to the flowchart shown in the figure. Note that the calculations in this flowchart are performed by the welding speed calculation section 194 in the main processing device 19.

First, initial values V0 of desired weld bead height and welding speed are set.
, the wire feeding speed setting value Vfo is input from the input device 20 to the main processing device 19 and stored in the memory 193 (step Sa).

Next, the calculation of A O = V fo / V O is performed,
Similarly, it is stored in the memory 193 (step Sb).

Further, the reference swing width W1 given in step SC of the swing width control flowchart in FIG. 4 is stored in the memory 193 (step Sc). This swing width W1 is WWO
shall be.

After the above, welding is started (step Sd).

Here, the arc rotation radial position at the start of welding is assumed to be el in FIG.

When the oscillation of 1.5 cycles is completed (step Se), step SG of the oscillation width control flowchart shown in FIG. 4 above is performed.
The swing width Ww given by is stored in the memory 193 (step Sf).

Let this swing width WW be Ww.

The welding speed during the above welding work is vo.

Next, the main processing unit 19 calculates (W□-Wwo)h (step Sg), and further calculates the welding speed V based on equation (12) regarding the welding speed V (step sh ).

The welding speed V is determined in the manner described above, and based on this welding is performed in a half-oscillation cycle (step Sj).

Here, a judgment is made as to whether or not welding is complete (step S
k) Depending on the result of the judgment, the welding is finished, or the above-mentioned operation of (step Sf)→(step Sj) is repeated until the welding is finished.

As described above, according to this embodiment, the bead height is kept constant by variably controlling the welding speed V with respect to changes in the swing width Ww.

Note that when performing the above-mentioned swing width control and welding speed control, the main processing unit 19 issues a swing reversal command based on the wire rotation speed detected by the wire rotation speed detector 22. From the above equation (7), the number of revolutions of the arc while the rotational axis O moves by the swing width W is given by 2(m-n). Furthermore, from the above equation (8), the number of revolutions of the arc while the rotational axis O moves by the swing width wwfJ is given by 2·(m−n±1). Therefore, once the swing width to be controlled is determined, the timing for giving the reversal command can be determined by detecting the arc rotation speed, that is, the wire rotation speed.

Next, an example of a method of detecting the groove width change ΔG based on the change characteristics of the arc voltage will be described.

As shown in FIG. 1, the wire 5 is connected to the left and right groove walls 2L, 2
The position closest to R is the wire rotation position L (WLl+
This is Rtwit.

Here, since the distance δ between the wire rotation position L +wb+ and the groove wall 2L is equal to the distance δ8 between the wire rotation position RTWR1 and the groove wall 2R (δ5=68), the arc characteristic explained in the above conventional technique is Accordingly, the detected value ELTW of the arc voltage at the rotational position L (wL+) and the rotational position R (□)
The detected value of the arc voltage E R+w+s+ is equal to (ELtwc+ =E*+w+n).

This detected value E1. When the groove width G changes, the magnitude of the value of WRI changes while maintaining the relationship of E + wb + = E * (w + n).

Therefore, this E L twL+ E R(WRI
If the value of
Furthermore, a detection value on the swing center WC is also detected. Since this swing center WC is the center of the groove 2, the wire rotation position L
(wL, the distance δCL in the groove width direction between the swinging center WC and the wire rotation position R (wH and the distance δCR in the tip width direction between the swinging center C and the swinging center WC are equal (δCL=δCR), so the swinging The detected value E Cf IWcI of the arc voltage at the wire rotation position CtLwc+ on the center WC and the detected value E
The following relationship holds true between L(W. and E R(WRI).

((ER+wR+ + EL+wt+) / 2
) -Ecttwc+=C Here, C is a constant determined by the size of the groove width G.

This equation (14) is written as follows for simplification.

(E m −E ct)
(14a) (However, EI = (ER(WRI +EL
IWLI) / 2*ECf indicates ECfTWC). ) The value of this equation (14a) indicates the value corresponding to the actual groove width G.

Also, the standard groove width G. Let Eo be the value of equation (14a) in
Then, this Eo is the standard groove width G. indicates the value corresponding to the size of .

The difference between the above equation (14a) and this EO, (E, -Ecr) -Eo = △E (15')
indicates a value corresponding to the magnitude of the groove width variation BΔG. This ΔE is compared with a set dead band having an upper limit E and a lower limit E2, and when E2≦△E≦E1, ΔG=0. When △EVE, △G=+g.

When ΔE<E2, it is assumed that ΔG=-g.

Next, a more specific detection method for determining the groove width change ΔG will be described with reference to FIG. FIG. 6 shows an example of a circuit block of the groove width change detection device 21 shown in FIG. 3. In FIG.

The above E*tw*+, Eb+wL+, Ecx
Since it is difficult to instantaneously detect wc+ due to the influence of noise, etc., here, the voltage waveform is integrated within the range of each integration angle φ0 and detected as an integral value. Furthermore, this integration is performed α times (α rotation of the arc) before and after the rotational axis 0 is on WR, WL, and WC, respectively. In this case, the moving distance of the rotation axis 0 in the groove width direction due to the swing while the arc rotates α times is expressed as (Vw/N)α, so the sections in which the above detection is performed are each WR ±(V,・α/2N) WL±(Vw・'a/2N)WC±(vw
*a/, 2N).

In FIG. 6, an arc voltage E is detected by an arc voltage detector 13E, and this detected arc voltage E is preset by a setting device 211.
The reference voltage E is the average value of the arc voltage E set to
The difference E-Eo with respect to O is calculated by the operational amplifier 212. This calculated value E-E0 is divided by a switch 213 and output. The timing of division by the switch 213 is determined by a command signal from the controller 214.

The controller 214 determines the detection range WL based on the swing positions WL, WC, W, R of the rotation axis 0 set in the swing position setter 215 and the processing number α set in the processing number setter 216.
±(Vy ・α/2N), WR:t (Vw ・α/2
N), WC±(Vw - α/2N) are determined, and these values are compared with the actual swing position of the wire axis detected by the wire swing position detector 217. Then, while the swing position of the wire axis is within the detection range WL±(Vw・α/2N), the wire rotation angle φ detected by the wire rotation position detector 218 and the predetermined 5″ to 180° A comparison operation is made between the output φ of the integral angle setter 219 which has set a certain angle φ in the range, and the rotation axis of the wire is determined to be
/2N) centered on the wire rotation position
. The waveform of this section is the L section, and the waveform of this section is the L section.
It is output from the L side of 13. Similarly, φ is centered at the wire rotational position Ct while the swinging position of the wire axis is within the detection range WC±(VW·α/2N). The section of Cf is defined as the section Cf, and the waveform of this section is output from the C side of the switch 213, and the swing position of the wire axis is within the detection section WR±(V
φ centered at the wire rotation position R while at w ・α/2N). The section is set as the R section, and the waveform of this section is output from the R side of the switch 213. L of switch 213
side, cr side.

The outputs from the R side are integrators 220, 221 and 222, respectively.
It is integrated by The integrators 220, 221, and 222 perform waveform integration on the rotation of the arc for α times (the number of processing times set in the setting device 216) outputted via the controller 214, and output S8.

SR and SCf are output to storage devices 223, 224, and 225, respectively. The memory 223, 224, 225 is the integrator 220
, 221, 222 input signals SL, SR, S
SL and SR are outputted to the adder 226 and SCf is outputted to one end of the differential amplifier 227 while repeating the storage and holding of ct for α times. The output SL+SR of the adder 226 is multiplied by 1/2 in the arithmetic unit 228, and the average value of SL and SR (SL+SR)/2=S is output. Arithmetic unit 22
The output S, of 8 is input to the other end of the differential amplifier 227, and in the differential amplifier 227, the difference (Ss-Scr
) is required. This difference (S, -3 cr) is output to one end of the differential amplifier 229. In addition, the memory device 230 has (
The initial value S0 of (S, -3 cr), that is, the value S0 corresponding to (S, -5 cr) when the standard swing width is given to obtain proper penetration with the standard groove width, is stored.

This value is given to the other end of the differential amplifier 229, and in the differential amplifier 229, (Ss -5cr) -S. =ΔS is determined. This value of ΔS is a value corresponding to the groove width change ΔG. Furthermore, ΔS is given to the discriminator 231.

On the other hand, the band having the upper limit S and lower limit S2 set in the dead band setter 232 is compared with ΔS by the discriminator 231,
The discriminator 231 selects 0. when S2≦ΔS≦S. When △S>Sl, 10g
, -g is output when ΔS<32.

Note that the angle φ set in the integral angle setting device 219 in the above explanation. The reason why the angle φ is set in the range from 5° to 180″ is that when the angle φ is less than 56, it is easily influenced by noise and becomes difficult to detect.The band set in the dead band setting device 232 is as follows. It is set appropriately depending on the magnitude of the predicted groove width variation ±g.

Next, control of torch movement in the X-axis direction, that is, groove tracing control will be explained. For the groove tracing control, the signals SL and SR obtained by the circuit block of the groove width change detection device 21 shown in FIG. 6 above can be used. SL and SR detected at the left and right edges of the groove will be equal (sL=SR) if the target position of the deviation is appropriate. Therefore, the difference 5L-5R between SL and SR is calculated, and this difference S, -
Bevel tracing control can be performed by correcting the position of the torch 3 in the X-axis direction so that SR becomes ;.

FIG. 7 shows an example of a circuit block of an X-axis control device 18X that performs drive control in the X-axis direction.

The signal SL is outputted from the memory devices 223 and 225 shown in FIG. 6 while repeating storage and holding α times.

SR is input to both input terminals of the differential amplifier 181X in FIG. 7, respectively. From this differential amplifier 181X, SL and S
A difference 5L-8R with respect to R is output, and this difference output is manually input to the X-axis motor drive controller 182x. The X-axis motor drive controller 182X moves the torch 3 in the X-axis direction via the X-axis motor IIX so that the difference output becomes a drop. In this way, groove tracing control is performed by correcting the position of the torch 3 in the X-axis direction.

Next, constant arc length control by the Y-axis control device 18Y will be explained.

FIG. 8 shows an example of a circuit block of the Y-axis control device 18Y that performs such control.

In FIG. 7, the detected arc voltage E from the arc voltage detector 13 is input manually to one end of the differential amplifier 181Y. On the other hand, the other end of this differential amplifier 181Y is connected to a setting device 1 in advance.
The reference value set to an appropriate value by 82Y is manually input. The amplifier 181Y outputs the difference between the reference value and the above-described detected value, and this difference output is input to the Y-axis motor drive controller 183Y. Y-axis motor drive controller 183Y
is such that the differential output becomes zero, that is, the arc voltage E
The torch 3 is moved in the Y-axis direction via the Y-axis motor 11Y so that the value becomes the reference value. This keeps the arc voltage E constant and the arc length constant.

Therefore, when the torch 3 moves in the X-axis direction, the torch 3 moves in the Y-axis direction along the groove wall. According to this control method, no matter how the groove shape changes, the tip of the torch 3 always rotates within the groove width while maintaining a constant distance from the base material surface 1a or the groove bottom surface 2b. will be repeated.

[Effects of the Invention] As described above, according to the present invention, since the swing width is variably controlled based on changes in the groove width, appropriate penetration can be obtained even when the groove width changes. .

Furthermore, since the welding speed is variably controlled based on the change in the oscillation width to compensate for the amount of welding, there is an effect that a constant bead height can be maintained even if the groove width changes.

[Brief explanation of the drawing]

Fig. 1 is a top view of a welded part for explaining the principle of the oscillating rotary arc welding method of the present invention, Fig. 2 is a side sectional view thereof,
FIG. 3 is a block diagram showing a control system related to the oscillating rotary arc welding method of the present invention, FIG. 4 is a flowchart showing the operation of oscillation width control, FIG. 5 is a flowchart showing the operation of welding speed control, and FIG. Figure 6 is a block diagram showing an example of the configuration of a groove width detection device, Figure 7 is a block diagram showing an example of a circuit block that performs groove copying, and Figure 8 is an example of a circuit block that performs constant arc length control. The illustrated block is a graph showing the waveforms of arc voltage E and welding current I that change in accordance with the position of the rotating wire. In the figure, 1 is a workpiece to be welded, 2 is a groove, 3 is a rotating arc torch, 19 is a main processing device, 20 is an input device, 21 is a groove width detection device, 22 is a wire rotation speed detector, and 192 is a rocker. The dynamic width calculation section 194 is a welding speed calculation section. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Patent Attorney Tadashi Sato Figure 4 Figure 5 io g

Claims (2)

[Claims] (1) The welding wire is rotated at high speed around the axis at a predetermined rotation radius to rotate the arc, the welding torch is reciprocated in the groove width direction within the groove, and the arc voltage or welding current is detected. However, when performing arc welding while controlling the welding torch position in the height direction relative to the base material to be welded so as to maintain a preset arc voltage or welding current while performing groove tracing using the arc sensor method,
A mechanically controllable oscillation is performed by setting in advance the average value ±g of the predictable variation in the size of the groove width in the groove width direction, and making it equal to the absolute value |g| of this average value ±g. Set a single position of the groove, and give an initial value of the oscillation width to obtain a predetermined penetration as an integral multiple of the single oscillation position with respect to the standard groove width, which is the design value of the groove width. A value corresponding to the groove width change is detected based on the change characteristics of the arc voltage or welding current with respect to the change in the width size, and this detected value is determined as 0, +g, or -g depending on the size. The oscillating rotating arc is characterized in that, based on the determination result, the oscillating width is controlled by increasing or decreasing the integer so that the penetration is maintained at a predetermined constant value with respect to changes in the groove width. Welding method. (2) When controlling the oscillation width by the oscillation rotary arc welding method according to claim 1, the controlled oscillation width is W_w, the oscillation width one cycle before is W_w_0, and the wire feeding speed is When V_f_0, the desired bead height is h, the initial value of welding speed is V_0, and the welding speed to be controlled is V, the following formula, V=V_f_0/{(V_f_0/V_0)+(W_w
-W_w_0)h} An oscillating rotary arc welding method characterized in that the welding speed is controlled based on the following: -W_w_0)h}.