JPS61276776A - Automatic weld line profiling method - Google Patents

Abstract

PURPOSE:To profile automatically an arc point to the weld line by using the parameter of the welding conditions at the welding time without providing a detecting mechanism close to a welding torch. CONSTITUTION:The extension LE of a wire 17 is found by detecting the welding current I and consumable electrode, namely the feeding speed V of the wire 17 and by processing with a computing element 39 the electrical signal expressing the welding current I and feeding speed V. The deviation with the groove center position of the joint composed of the rocking center position of the wire 17 and the body 19 to be welded is detected from the difference in more than two pieces of the wire extension LE in the prescribed rocking position of the wire 17. The positions of the torch main body 3 and fitting body 4 are controlled so that the relative position of the rocking center position and the groove center position become as the setting and the mean value of the wire extension LE in the rocking positions more than two pieces becomes as the setting.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an automatic welding line tracing method, and is useful when applied to arc welding using a consumable electrode (hereinafter referred to as a wire).

<Prior Art> Conventionally, in arc welding using a wire, a method has not yet been found that calculates the sum of the wire protrusion length and the arc length during welding and traces the weld line from the change. When welding Ptl objects by wire arc welding, it would be advantageous from a structural standpoint if the welding torch could automatically follow the welding line without providing a special detection mechanism near the welding torch. It is.

<Problems to be solved by the Invention> The present invention has been made in view of the above points, and is capable of detecting welding conditions during welding without providing any other tangible detection mechanism near the welding torch in arc welding using a wire. The object of the present invention is to provide an automatic welding line tracing method in which an arc point automatically follows the welding line using parameters.

Means for Achieving the Object> The configuration of the present invention to achieve the above object is to insert a consumable electrode whose tip protrudes into the groove in the welding line automatic tracing method in the consumable electrode arc welding method. The fitting body is fitted into the torch body so that it can swing around its axis, and the welding current! and the feeding speed V of the consumable electrode are detected, and the electric signals representing the welding current (2) and the feeding speed V are processed by a calculator to obtain the protrusion length -1 of the consumable electrode, and the predetermined length of the consumable electrode is The opening of the joint formed by the center position of the consumable electrode and the object to be welded is determined from the difference between the protrusion length LE at any two arbitrary swing positions obtained from the value of the protrusion length LE at the swing position. The deviation from the tip center position is detected, and the relative position between the swing center position and the groove center position is as set, and the average value of the protrusion length at at least two swing positions is as set. The present invention is characterized in that the positions of the torch body and the fitting body are controlled.

Example of implementation Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a block diagram showing an apparatus for implementing an embodiment of the present invention. As shown in the figure, the output voltage of the welding power source 1 is adjusted by the voltage regulator I#2, and the welding current is applied to the wire 17 via the welding tip 5, which is the tip of the torch body 3. is supplied. The torch main body 3 is formed to be movable up and down by having its upper part fixed to the other end of a metal fitting 25 whose one end is fixed to a vertical moving jig 25 that moves in the vertical direction in FIG. 9 by the drive of an electric motor 27. In addition, the metal fittings 28
It is fixed to the trolley 29 via a screwdriver and is movable in a direction perpendicular to the plane of the drawing. Further, the torch main body 3 pivotally supports the fitting body 4 via an arm 11 fixed to a metal fitting 25 and a bearing 9 fixed to this arm 11. The fitted body 4 is
A gear 8 is fixed to its upper end, and rotational force is transmitted when the gear 8 meshes with a gear 7 that is rotationally driven by an electric motor 6 fixed to the torch body 3 via a metal fitting 21. It looks like this. Thus, the fitted body 4
is capable of swinging within the torch body 3 about the axis of the torch body 3 by driving the electric motor 6 . The amount of rocking at this time is detected by a potentiometer 24 fixed to the metal fitting 21 via the metal fittings 21 and 23. The wire 17 is fed through the conduit cable 16 attached to the upper end of the fitted body 14 via the universal joint 10 by unwinding the coiled wire 13 with the roller 12, and is eccentric from the axial center of the fitted body 4. It is inserted into the fitting body 4 via a groove cut in the axial direction at the position, and the tip thereof projects obliquely from the welding tip 5 into the groove. At this time, the roller 12 is rotationally driven by the electric motor 14, and the rotation speed of the electric motor 14, that is, the wire feeding speed V is controlled by the control device 15. In the figure, 18 is an arc, 19 is a weld metal, and 20 is an object to be welded.

Further, 30 is a shunt that detects the welding current l, 31 is an encoder that detects the feeding speed V of the wire 17, 32 is an amplifier that makes the detection signal of the potentiometer 24 an appropriate magnitude, and 33 is a pulse of the encoder 31. The amplifier 34 converts the signal into a DC voltage and makes it to an appropriate size, filters the signal from the shunt @ 30 and outputs the welding current! average value ζ
An amplifier 35 squares the signal from the shunt 30, averages it over time, and then calculates the square root to find the effective value l of the welding current I and adjusts it to an appropriate size. An amplifier 36 is an amplifier that adjusts the signal from the setting word 37 for sensing gain (K8.2...described later) and protrusion length reduction (described later) to an appropriate magnitude. These amplifiers 32.33
．． The output signals of 34.35.degree. After performing a predetermined calculation to be described later, the calculation unit 39 transmits a control amount according to the result to the control device 4 via the D/A converter 40.
Supply at 1.42. At this time, the control device 41
The direction and amount of rotation of the electric motor 6 is controlled based on the signal from the converter 40, and the control device 42 controls the direction and amount of rotation of the electric motor 27 based on the signal from the D/A converter@40.

In such a device, as shown in FIG. 2, which is a cross-sectional view taken along line A-A in FIG. 3, the position of the wire 17 also changes depending on the magnitude and direction of the rotation.

Fig. 3 (al, (bl) to Fig. 5 (al, (bl) shows that when the fitting body 4 is rotated relative to the torch main body 3, the wire 1
The state in which the tip of 7 is changing (swinging) is shown.

At this time, since the fitting body 4 and the electric motor 6 are coupled via the gears 7 and 8, and the potentiometer 24 is also mechanically coupled, the electrical signal of the potentiometer 24 changes in accordance with the swinging position of the wire 17. do. That is, wire 1
7 ms mθ can be detected by the potentiometer 24. Also, the average value of the welding current I by the shunt 30 and amplification @35, 36! , and the effective value ■, the wire feeding speed V is determined by the encoder 31 and the amplifier 33, and the swinging position of the wire 17 is determined by the potentiometer 24 and the amplifier 32, and the electric signals representing these are A/D converted w438. Operation via M39
be supplied to.

Here, we define the symbols again as follows.

I... Average welding current (average value of welding current), ■...
Effective welding current (effective value of welding current), V...Wire feeding speed, -...Length of wire 17 from the tip of welding tip 5 to arc 18, ie, wire protrusion length.

When each symbol is defined as above, it is known that the following relationships exist between the various quantities.

L, = f, (1,,I,,v)
...■ Therefore, the relationship of formula (■) is programmed into the calculator 39, and the welding current 1. ．． 1. When the wire feeding speed V is given, the wire protrusion length - is determined.

To explain this embodiment method using such welding parameters, FIGS. 6 to 8 show the swing angle θ (maximum swing angle ±
It is a θ-L pattern in which the relative angle (relative angle taken as 100%) and Lt (wire protrusion length) are taken on the vertical axis, and the center line of the oscillation defined next is at the groove formed in the workpiece 20. This shows the case of swinging in parallel and with the same amplitude. The center line of the swing at this time is shown in Fig. 3(a).

(b) to Fig. 5(a), (In bl, the line segment connecting the center point of the fitted body 4 and the cross-sectional center point of the wire 17 is a bisector of the angle spanned by the maximum positive and negative points of θ. This is the line that becomes .

FIG. 6 shows a case where the center line of the swing is parallel to the groove and at the center of the groove, but in this case it is symmetrical about the axis (θ=0).

FIG. 7 shows a case where the center line of the swing is parallel to the groove, but its position is between the center line of the groove and the left wall of the groove.

In this case, the center of the torch body 3 is on the left side with respect to the center of the groove, and the size of L decreases rapidly as θ=−100% approaches.

In Fig. 8, contrary to Fig. 7, the center of the torch body 3 is on the right side with respect to the center of the groove, and θ = +100%.
As it approaches , the size of L decreases rapidly.

FIG. 9 shows the change in the swing angle θ with respect to time t, and
Welding current 1. #I, #Indicates the timing of sampling the wire supply speed V.

The starting point of sampling is θ=0 for both positive and negative values of θ, and the interval therebetween is Δt. In addition, the LE with the first sampling number in the figure is LEl, and the statistics of the LEs from the first sampling number to the nth LE when θ>0 are i Ll!
,,The statistics of LE from the number of LE samplings 1 to m when θ is 0 are expressed as iL6, and the detected amounts ΔD and ΔH of the deviation of the torch (and J-hi is the arc point) with respect to the welding line are expressed as follows. Define it as follows.

Or Here, Kl is a proportionality constant.

Here, H, and K2 are proportional constants, and - is a set value of the protrusion length.

By the way, in the case of Fig. 6, the θ-L pattern is almost symmetrical with respect to the axis θ=0, so ΔD=0, and in this case, the center line of the groove and the center line of the swing coincide. Therefore, there is no need to control the swinging center rod.

In the case of Figure 7, ΔD>O, so in this case ΔD=
= 0 until the control device i! 42, the center line of the swing by the electric motor 6 is moved to the positive side of θ.

In the case of Fig. 8, ΔD<0, so in this case Δ04
The center line of the swing by the electric motor 6 is moved to the negative side of θ through the control device 41 until it becomes 0.

In all of the cases shown in FIGS. 6 to 8, the swing angle is kept constant and the center line of the swing is changed to correct the deviation of the center line of the torch body 3 with respect to the center line of the groove, and the swing is always performed. control so that the center line of the groove almost coincides with the center line of the groove.

If the height direction deviates for some reason, the height of the torch is controlled by controlling the height of the vertical moving jig 26 by the electric motor 27 through the control device 42 so that ΔH is always zero.

<Effects of the Invention> As specifically explained above in conjunction with the embodiments, according to the present invention, the arc point automatically follows the welding line, so a welded part without welding defects can be obtained. Incidentally, in the case of a narrow groove, if the center line of the groove and the arc trajectory in the direction of the weld line do not match,
Welding defects are likely to occur. In addition, if combined with a welding robot or the like, it will be possible to fully automate even the welding line fluctuations during welding.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an apparatus for realizing the implementation method of the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 (
al~Figure 5(a) is an enlarged cross-sectional view of the vicinity of the tip of the torch body, corresponding to each state when the wire swings, and Figures 3(b)~Figure 5(b) are Figure 3 (, 1 to 5
The bottom view of the vicinity of the torch main body shown in Figure (a) as seen from below, and Figures 6 to 8 show the θ - 9 is a graph showing the patterns of the swing angle θ with respect to time t.
FIG. 2 is an explanatory diagram showing the timing of sampling of a welding parameter necessary to calculate a change in LE and a welding parameter. In the drawings, 3... Torch body, 4... Fitting body, 5... Welding tip, 17... Wire, 18... Arc, 19... Weld metal, 20... Welded object, 30... shunt, 40... arithmetic unit.

Claims (1)

[Claims] In the automatic welding line tracing method of consumable electrode arc welding, a fitting body into which a consumable electrode whose tip protrudes toward the groove is inserted is fitted into the torch body so that it can swing around its axis. At the same time, the welding current I and the feed speed v of the consumable electrode are detected, and the electric signals representing the welding current I and the feed speed v are processed by a calculator to determine the protrusion length L_E of the consumable electrode. Protrusion length L_ at any at least two swing positions determined from the value of protrusion length L_E at a predetermined swing position of the electrode
From the difference in E, the deviation between the swing center position of the consumable electrode and the groove center position of the joint formed by the workpiece to be welded is detected, and the relative position between the swing center position and the groove center position is as set. An automatic welding line tracing method characterized in that the positions of the torch body and the fitting body are controlled so that the average value of the protrusion length L_E at at least two swing positions is as set.