JPS5828026B2 - automatic welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an automatic welding device in which the torch electrode itself is used as a sensor.

The applicant previously filed Japanese Patent Application No. 52-50445 (Japanese Unexamined Patent Publication No. 54-1
5441) for automatic welding along the welding line of the workpiece by controlling the relative positions of the torch and the soak, wherein a separate power source for the sensor is connected to the electrode of the torch,
The application has been filed for an automatic welding device in which the welding line is detected by determining the mutual position of the electrode and the workpiece by electric discharge caused by their proximity, and then the electrode is switched to a welding power source to perform automatic welding. .

The automatic welding device mentioned above uses the torch electrode itself as a sensor, and there is no need to attach a special sensor around the torch, so the structure around the torch is particularly simple and the torch can fit into the workpiece even if it has a complex shape. It can be said that this is an advantageous device compared to a device with a separate sensor, as it can detect weld lines anywhere.

However, this automatic welding device was equipped with two power sources, a welding power source and a sensor power source, and the torch electrode was selectively connected to one of the two power sources depending on the purpose of use using a changeover switch. However, the electrical equipment and wiring components required for the sensor power source and power source switching means, which are separate from the power source device dedicated to the welding power source, are expensive, and there are also problems in terms of space.

In view of the above-mentioned circumstances, the present invention is provided with one power supply device, and the power supply device has welding voltages and voltages set in advance based on welding commands or sensor commands from a separately provided control box with a built-in computer. The sensor voltage is selectively applied to the torch electrode, and only during sensing, the energization state between the electrode and the workpiece is controlled by the current and /
Or detect it as a change in voltage, send that information to the control box, and control the relative positioning of the torch and workpiece based on that information. An object of the present invention is to provide an automatic welding device that does not require any power supply switching means, has low equipment cost, is compact, and can use a torch electrode as a sensor.

To explain in detail the embodiment shown in the figure, in FIG. 1, an automatic welding apparatus 1 is configured such that a workpiece fixture 2 for a workpiece W can be moved in the left-right X direction and the front-back Y direction, and can be rotated around a horizontal axis H. A control box 5 for controlling the movement and swinging position of the workpiece W and the torch 3, which is configured such that the torch fixture 4 of the torch 3 is movable in the up and down Z directions and swingable around the vertical axis. has been established.

This will be explained in more detail below.

Reference numeral 6 denotes a flat, square-shaped base, on one side of which a first frame 7 is fixed.

Reference numeral 8 denotes a cart placed on the first frame 7, which is driven by a speed reducer and a foot/reverse motor with a brake (not shown) to move in the left-right direction via an appropriate transmission means (not shown) such as a ball screw. (in the direction of arrow X).

Reference numeral 9 denotes a second frame fitted to the truck 8, which is movable in the front and back direction (direction of arrow Y) by the same driving and transmission means as the truck 8, and the front end of the second frame 9 has a The aforementioned workpiece fixture 2 is attached so as to be rotatable around the horizontal axis @H (in the direction of arrow θ).

10 is a vertical frame erected on the other side of the L shape of the base 6;
A horizontal arm 11 is attached to the side surface so as to be movable in the vertical direction (arrow 2 directions), and the aforementioned torch mount 4 is attached to the tip of the horizontal arm 11 so as to be swingable around the vertical axis (arrow F direction). .

The driving means for the horizontal arm 11 and the torch mount 4 are both foot/reverse motors with brakes (not shown).

Further, the torch 3'd is attached to the tip of the torch mount 4 so that the welding point WP on the extension of the center line is always on the vertical axis, and the angle of the attachment 9 is determined according to the welding mode (butt welding) (fillet welding, etc.) and the shape of the work W.

12 is a welding/sensor power supply device for applying voltage and supplying current to the electrode W of the torch 3; 13 and 14 are an electrode supply roll and a pair of electrode feeding rollers attached to the power supply device 12, respectively; , the electric current is the feed roller 14
The material is pulled out from the supply roll 13 by the drive of , and is fed to the torch 3 through a flexible tube 15 having a loop-shaped deformed portion 15a formed in the middle.

16 is a welding control instrument derived from the power supply device 12 and attached to the control box 5.

Reference numeral 17 denotes a remote control panel, which remotely controls the movement and rotation of each part by manual operation, and inputs a user program into the memory (not shown) in the control box 5 based on the remote control. It is.

The control box 5 then controls each drive source (reducer and brake forward rotation/reversing motor)
While automatically controlling the commands for reversing and moving, their speeds, and the current and voltage for welding or sensors, the torch is set so that the recess contact point WP of the torch 3 is along the welding line WL of the workpiece W and the welding conditions are optimal. The relative positions of the workpiece fixture 2 and the torch fixture 4 are controlled so that automatic welding can be performed in the position shown in FIG.

FIG. 2 is a block diagram of a control circuit that is built in as the welding/sensor power supply device 12 and shows the control system of a DC arc welding machine that controls the output voltage using a thyristor. feeding means 200;
It is composed of three control blocks of the energization state detection means 300.

The voltage application means 100 are connected to each other from the control box 5.
It is equipped with a welding command activation signal generation circuit 101 and a sensor command signal generation circuit 102 which receive a welding command and a sensor command and generate signals, and these outputs are used for a welding output voltage setting circuit 103 and a sensor command, respectively. Both of them reach an output voltage control circuit 105 via an output voltage setting circuit 104, and a preset output voltage for welding or a sensor is applied to the electrode W via a thyristor rectifier stack 106.

Further, the electrode feeding means 200 includes an electrode feeding amount setting circuit 20.
1. Electrode feeding motor control circuit 202, electrode feeding motor 2
03, and an electrode feeding motor braking circuit 204,
Only while the electrode feeding motor braking circuit 204 is inputting the "welding command" signal from the welding command signal generation circuit 101, the braking of the electrode feeding motor 203 is released and the electrode feeding motor 203 is driven. The electrode supply roller 1 is rotated at a preset speed by the rotation of the electrode supply roller 14.
The electrode W is drawn out from the torch 3 and fed to the torch 3.

Further, the energization state detection means 300 includes an energization state detection circuit 301 and an energization state detection output circuit 302.

Of these, the detection circuit 301 has a built-in cut-off circuit (not shown) as appropriate, and when a "welding command" signal is input from the welding command signal generation circuit 101, it is deactivated via the cut-off circuit, and only when a sensor is detected. Upon receiving the input of the energization state from the electrode W, the energization state caused by proximity discharge between the electrode W of the torch 3 and the workpiece W, that is, the change in current, voltage, or both, is detected, and the detection signal is output as the energization state detection output. The signal is sent to the control box 5 via the circuit 302.

Hereinafter, a workpiece W constructed by using the electrode W of the torch 3 as a sensor and butting together a horizontal member W1 and a vertical member W2 extending in the X-axis and Z-axis directions perpendicular to each other, respectively.
When sensing the welding point at one end position of the fillet layer tangent WL extending in the Y-axis direction (Fig. 3), the fourth
, 5 will be explained with reference to the flowchart shown in FIG.

First, the computer built in the control box 5 is set to teaching mode, and the operation buttons (not shown) on the remote control panel 17 are manually operated, and the welding point WP of the torch 3 is brought to a position near one end of the welding line WL using a known playback method. , positional information X1°\1. Z1 is input together with the sensor command as one step of the user program, and a series of user programs are further input.

Then, the computer is activated in auto mode, and the aforementioned user program is output step by step as command information accordingly.

Below, the operation according to the sensing steps will be explained one by one.

(1) First, it is determined whether the program includes a sensor command.

(2) If it does not contain a welding command, it is determined whether or not it contains a welding command, and if it does, the welding command signal generation circuit 10
According to the welding command, a welding output voltage preset in the welding output voltage setting circuit 103 is applied to the electrode W via the output voltage control circuit 105 and the thyristor rectifying stack 106.

Then, automatic welding is executed according to the program, but at this time, since the energization state detection circuit 301 is inactive by the built-in appropriate cutoff circuit, the current and/or voltage output from the electrode W is not transmitted to the energization state detection circuit 301. Not entered.

(3) If the sensor command is included, then the sensing mode number is determined.

When the sensing mode is set to 1 to N, an error message is displayed if the sensor is not in the fall sensing mode.

For example, for horizontal fillet welding on a workpiece W as shown in FIG. 3, sensing mode 1 is determined, and subroutine 1 is executed.

In this subroutine 1, a command is first outputted to the sensor command signal generation circuit 102 according to the flowchart shown in FIG.

The output from the sensor command signal generation circuit 102 is sent to the output voltage control circuit 10 via the sensor output voltage setting circuit 104.
5, thereby applying a sensor voltage to the electrode W via the thyristor rectifier stack 106, such that the electrode W does not melt when energized.

The welding point WP at the tip of the electrode W of the torch 3 is the start position P1 (Xl, Yl) taught in advance.

The position is controlled by Zl).

Incidentally, at this time, the protrusion length of the electrode W from the torch 3 is adjusted to a constant value by an appropriate electrode protrusion length adjustment operation (not described in detail) performed each time automatic welding is completed.

Further, since the "welding" signal is not input from the welding command signal generation circuit 101 to the electrode feeding motor braking circuit 204, the electrode feeding motor 203 is not braked, and thereby the adjusted electrode W A constant protrusion length is maintained.

(4) Next, output a command to lower the torch 3 in the Z-axis direction.

Accordingly, the torch 3 is lowered in the 5Z-axis direction from the position P1 toward the upper surface f1 of the horizontal member W1.

(5) During the lowering, if the tip of the electrode W comes close to the upper surface f1, electricity will flow between them, a change in voltage and/or current will be detected by the energization state detection circuit 301, and a change in the voltage and/or current will be detected by the energization state detection output circuit 302. A signal is issued, the descending of the torch 3 is stopped, and the position P2 (XI, yt, Z2) is reached.
The Z-axis direction position information Z2 is taken in.

(6) Output a command to raise the torch slightly in the Z-axis direction,
The torch 3 is controlled to move upward from the position P2 by 1 to 2 steps to a position P3 (Xl, Yl, z3).

(7) Next, determine the sensing direction and orientation.

In this case, the torch 3 is moved in the 5X axis direction (rightward) from the position P3 toward the vertical member W2.

(8) During the movement, the tip of the electrode W is connected to the vertical member W2.
When approaching the left side f2 of the torch 3, electricity is applied between them, a signal is generated from the energization state detection output circuit 302 via the energization state detection circuit 301, the movement of the torch 3 is stopped, and the torch 3 is moved to its position P4.
X-axis direction position information X4 of (X4, Yl, zs)
Incorporate.

(9) In accordance with the command to move the torch back a little in the X-axis direction, the torch 3 is position-controlled to position P5 (X5, Yt, Z3), which is 1 to 2 steps back to the left from the position P4.

(10) This determines the completion of sensing, and erases the sensor command to the sensor command signal generation circuit 102.

0υ X-axis direction and position P including position P2 from the imported X-axis direction position information X4 and Z-axis direction position information Z2
Intersection position P6 with the Z-axis direction including 4 (x4.y□, Z2
), and each position information X4. Y1. Output Z2.

Of course, this intersection position P6 will be one point on the welding line WL if the upper surface f1 and the left side surface f2 intersect at a right angle.

This completes the sensing step, and the intersection point P6
The position command for the torch 3 is executed using the welding point command position Pi, but the actual welding point command position Pi takes into account the material, plate thickness, welding conditions, etc. of the workpiece W, and moves from the intersection point P6 to the opposite side of the workpiece. Position information shifted by a distance of △X in the X-axis direction and △Z in the Z-axis direction (Xi = X4 + △X,
Y, ,ZiZ2±△Z).

Although the electrode of the torch 3 has been described as a consumable electrode, it is clear that this can also be implemented in the case of a non-consumable electrode, such as a TIG welding torch.

Furthermore, if the voltage preset in the sensor output voltage setting circuit 104 is higher than the welding voltage, the arc gap will be almost constant regardless of the condition of the work surface or the electrode tip, and accurate sensing will always be possible. Although it is possible, the present invention is not limited to this, and the sensor voltage may be lower than the welding voltage as long as the surface condition of the workpiece and/or electrode is maintained well by appropriate means.

As detailed above, according to the present invention, a welding command signal generation circuit and a sensor command signal generation circuit are installed in parallel in a control enclosure built into one power supply device, and the outputs of these are respectively used as welding outputs. A welding command is inputted to the output voltage control circuit through the voltage setting circuit and the output voltage setting circuit for the sensor, and is sent from the computer built in the separately provided leg tube to the welding command signal generation circuit or sensor command signal generation circuit. Alternatively, a preset welding voltage or sensor voltage is selectively applied to the torch electrode based on the sensor command, and changes in current and/or voltage due to proximity discharge between the electrode and workpiece are applied only during sensing. The state is detected by the state detection circuit, and the output is sent to the control box via the energized state detection output circuit.
The control box controls the relative position of the torch and workpiece based on this information, so there is no need for a means to switch between the two power supplies for welding and sensor, as in conventional equipment, and only one power supply is required. An inexpensive and compact automatic welding device can be obtained in which the electrode of a torch, which serves as a power source for welding and a sensor, can be used as a sensor.

[Brief explanation of the drawing]

The drawings all show embodiments of the present invention; Fig. 1 is an overall perspective view of an automatic welding device, Fig. 2 is an explanatory diagram mainly showing a control circuit block diagram of a power supply device, and Fig. 3 is an illustration applicable to the present invention. FIGS. 4 and 5 are sensing flowcharts. In the figure, 1 is an automatic welding device, 2 is a workpiece fixture, 3 is a torch, 5 is a control box, 12 is a welding/sensor power supply device, W is a workpiece, and W is an electrode.

Claims (1)

[Scope of Claims] 1. In a device that automatically welds a workpiece and a torch while controlling their relative positions by appropriate control means, each electrode of the torch is preset by a welding command or a sensor command from the control means. one power supply device including voltage application means for selectively applying welding and sensor voltages of a given magnitude, and means for detecting the energization state of the electrode, and each of the voltage application means receives the welding command. A welding command signal generation circuit and a sensor command signal generation circuit generate signals in response to sensor commands, a welding output voltage setting circuit and a sensor output voltage setting circuit to set the voltages for welding and sensor respectively in advance. The circuit includes an output voltage control circuit that selectively inputs the output of either of the output voltage setting circuits to apply the welding or sensor output voltage to the electrode, and the control means detects the energization state. An automatic welding apparatus characterized in that an "energization" signal between the workpiece and the electrode is inputted from a means to calculate a command position and execute the relative position control. 2. The energization state detection means includes an energization state detection circuit that detects changes in current and/or voltage due to close discharge between the electrode and the workpiece, and an energization state detection circuit that transmits signal information from the circuit to the control means. An automatic welding device according to claim 1, comprising a detection output circuit. 3. The automatic welding apparatus according to claim 2, wherein the energization state detection circuit includes a cutoff circuit that receives a welding command number generated by the voltage application means and rejects energization input between the workpiece and the electrode.