JPH0284268A - Welding automatic control method for structural steel joint by automatic welding machine - Google Patents

Abstract

PURPOSE:To perform welding without causing end defects by oscillating and elevating a welding torch when it approaches a welding end to allow the welding torch to approach a welding place and changing over an electric current to the crater current and changing over the current to the welding current when the welding torch attains the welding end to perform welding at the prescribed position. CONSTITUTION:When the welding torch 6 approaches the welding end of base metal 1, the welding torch 6 is oscillated and elevated by operations of an oscillating motor and an elevating motor respectively and allowed to approach the welding place. In addition, the current is changed over from the welding current to the crater current. When the welding torch 6 attains the welding end, the current is changed over from the crater current to the welding current and while correcting the tip height of the welding torch 6, its oscillating direction is reversed. When the position of the welding torch 6 attains the center of the oscillating range, it is controlled so as to perform welding at the prescribed position. By this method, welding without causing the end defects can be performed.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a welding control method when welding a joint part of a steel frame using an automatic welding machine, and in particular, a flux tab is installed at the welding end. The present invention relates to a welding control method for welding.

(Prior art) The connection point between the end of a column member such as a square vibrator and a partition wall,
When using an automatic welding machine to weld a joint such as a joint between a bulkhead fixed to the end of a column member and a cross member such as an H-beam, attach end tabs such as steel tabs or flux tabs to both ends of the weld. Welding is performed by running a welding torch held on a trolley along the welding line.

(Problem to be solved) However, in conventional automatic welding machines, the welding torch is fixed to a torch holder in a fixed position, and the torch holder is supported by a trolley that runs along the welding line so that it can move in and out. , the torch holder is moved in and out in a direction perpendicular to the welding line to perform weaving. For this reason,
With conventional automatic welding machines that weld joint parts, if a flux tab is attached to the end of the weld, the casing of the torch will come into contact with the flux tab at the weld end, so There was a problem in that the melt penetration was insufficient and welding defects were likely to occur at both ends.

The present invention has been made with attention to such points, and an object of the present invention is to provide a welding control method that can automatically weld a joint part using a flux stub without causing defects.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, the retractable shaft holding the welding torch at the tip is configured to be rotatable within a certain angle range, and When the welding torch reaches a certain distance, the welding torch is swung along the welding line in a direction in which the tip approaches the welding end by rotating and swinging the retracting shaft, and the tip of the welding torch moves toward the welding end. The height is corrected by moving up and down to approach the welding point, and when the tip of the welding torch reaches a certain distance just before the welding end, the current supplied to the torch is switched from welding current to crater current, and the tip of the welding torch is changed from welding current to crater current. When the welding reaches the welding end, the current supplied to the torch is switched from crater current to welding current, and the direction of swing is reversed while correcting the height of the tip of the welding torch, so that the welding torch position is at the center of the swing range. When the torch reaches this point, the oscillation and height correction are stopped, and the torch is controlled to weld while being held in a constant position.

(Function) In the present invention, the retractable shaft holding the welding torch at the tip is configured to be rotatable within a certain angle range, and when the welding torch reaches a certain distance in front of the welding end, the retractable shaft By rotating and swinging the welding torch, the welding torch is swung along the welding line in a direction in which the tip approaches the welding end, and the height is corrected by moving the welding torch up and down so that the tip approaches the welding location. When the tip of the welding torch reaches a certain distance just before the welding end, the current supplied to the torch is switched from welding current to crater current, and when the tip of the welding torch reaches the welding end, the current is supplied to the torch. The current is switched from crater current to welding current, and the direction of swing is reversed while correcting the height of the tip of the welding torch. When the welding torch position reaches the center of the swing range, swing and height correction are stopped. Since the torch position and current are controlled so that welding is performed while the torch is held in a fixed position, the casing of the welding torch will not be obstructed by the tab due to the welding torch swinging. In addition, by controlling the current supplied to the torch at the welding end, welding can be performed without causing defects.

(Example) FIG. 1 is a flowchart of the method of the present invention, and FIG. 2 is a perspective view of essential parts of an automatic carbon dioxide arc welding machine used in the method of the present invention.

This automatic carbon dioxide arc welding machine has a base part (2) that is fixed to the welding base material (1), and a traveling base part (3) that moves in parallel along the welding line using the base part (2) as a guide. , an elevating platform portion (4) that moves up and down guided by the traveling platform portion (3), and a torch holder (5) that moves in and out in a direction perpendicular to the welding line while being guided by the elevating platform portion (4). , and a welding torch (6) fixedly held at the tip of a torch holder (5). The traveling platform part (3) is
As shown in Fig. 3, the drive consists of a traveling electric motor (7) built into the base part (2) and a threaded rod (8) with a ball screw structure connected to this electric motor (7). The mechanism is configured to move linearly in a plane along the base portion (2). In addition, as shown in Fig. 4, the elevating platform portion (4) includes an elevating electric motor (path shown) built into the traveling platform portion (3), and a ball screw structure screw connected to this electric motor. A drive mechanism consisting of a rod (9) is configured to move the carriage portion (3) up and down linearly. Furthermore, as shown in FIG. 5, the torch holder (5) is connected to an electric motor (10) for egress and egress built into the elevating platform portion (4). It is configured to move forward and backward by a drive mechanism consisting of a ball screw structure screw stud (11), while a swing shaft (13) linked to a reversible swinging electric motor (12) It is assembled so that it can move linearly and cannot rotate relative to each other, and the torch holder (5) is attached to the swing shaft (13).
It is configured to be able to swing within a certain angular range around the axis.

Then, this torch holder (5) is connected to the exit/exit motor (10).
) is formed so as to perform weaving by moving it in and out. That is, by operating these three drive mechanisms, the welding torch (6) can be freely moved in three dimensions.

Note that the electric motor for each drive uses a motor that can be switched between forward and reverse rotation.

A method of welding a joint portion using the automatic welding machine having the above configuration will be explained based on the flowchart of FIG. 1. The description will be made assuming that the direction of movement of the torch holder (5) is the X direction, the direction of movement of the elevator platform portion (4) is the Y direction, and the direction of movement of the traveling platform portion (3) is the X direction.

First, set the automatic welding machine on the part to be welded with the inner surface of one flux tab aligned with the welding origin, and set the plate thickness (T), weld length (L), and groove of the base material (1). Input the gear knob dimension (G) as the welding condition. Thereby, the number of welding layers is calculated and stored in the storage section of the CPU.

After that, when you press the start switch, the running motor (7
) operates and moves the welding torch (6) a certain distance (for example, 60 mm) I! from the welding origin in the X direction. tI to the start position (step 5IOI).

When the welding torch (6) reaches the start position (step 5102), the operation of the travel motor (7) is stopped, and the travel of the travel base portion (3) in the X direction is stopped.
Swing shaft (13) on which the welding torch holder (5) is fitted
The welding torch (6) is swung so that its tip approaches the welding origin by operating the swinging electric motor (12) and lifting motor connected to the welding torch (6). The lifting platform portion (4) is moved downward so that the tip approaches the welding location (step 5103). In this case, the descending speed of the lifting platform part (4) is given by the following equation: teY = k (1-Cosθ) with respect to the swing angle (θ), where k is the length from the center of swing of the welding torch (6) to its tip. It is set so that the length that satisfies the relationship can be moved synchronously. Therefore, the distance between the base material (1) and the tip of the welding torch (6) can be maintained constant regardless of the attitude of the welding torch (6).

Then, when the tip of the welding torch (6) reaches a certain position (for example, 5 mm) in front of the inner surface of the flux stub (welding origin) by swinging (step 5104), the arc is started by the crater current, and the swinging The welding torch (6) continues to move toward the origin due to the motion (step 5IQ5).

When the tip of the welding torch (6) reaches the welding origin position (step 5I06), the current supplied to the welding torch (6) is switched to the main welding current. Then, the swinging electric motor (12) and the lifting motor are operated in reverse (step 3107), and the swinging operation and the associated rising operation are performed until the swinging torch (6) or the swinging center is reached. Welding is performed by (step 3108).

When the oscillating welding torch (6) reaches the oscillating center (step 5109), the oscillating electric motor (1
2) and the operation of the lifting motor is stopped (step 5ilo), and the traveling motor (7) is activated to move the welding torch (6) in the X direction while maintaining a constant posture, and welding is performed. Continue (step 5Ill).

When the welding torch (6) reaches a certain distance (for example, 60 mm) before the welding end (step 5112), the operation of the travel motor (7) is stopped, and the travel table portion (3) is moved in the X direction. The welding torch
6) so that the tip of the welding torch (6) approaches the welding end, and the lifting table part (4) is moved downward so that the tip of the welding torch (6) approaches the welding location (step 5113). .

Then, due to the swinging of the welding torch (6), its tip is placed at a certain position in front of the inner surface of the flux tab on the terminal side, for example, 2f.
fi111) (step 5l14), the current is switched to the crater current, and the welding torch (6) continues to move toward the terminal end by swinging the head (step 5l14).
15).

When the tip of the welding torch (6) reaches the welding end position (step 5116), it is determined whether or not the final layer has been welded (step 5117). If it is not the final layer, the current supplied to the welding torch (6) is determined. The welding torch (
6) Welding is performed by the oscillation operation and the associated upward movement until the oscillation center is reached (Step 5 II 9
).

When the oscillating welding torch (6) reaches the oscillation center (step 5120), the oscillating electric motor (1
2) and the operation of the lifting motor is stopped (step 5I21), and the traveling motor (7) is activated to move the welding torch (6) in the direction of the welding origin while maintaining a constant posture, and welding is performed. Continue (step 5122)
.

Then, the welding torch (6) is moved a certain distance (
For example, 60 mm), in step 5I23), the operation of the traveling motor (7) is stopped, and the traveling of the traveling base portion (3) toward the welding origin is stopped. The lifting motor is operated to swing the welding torch (6) so that its tip approaches the welding origin, and at the same time move the lifting platform (4) so that the tip of the welding torch (6) approaches the welding point. is moved downward (step 5I24).

By swinging the welding torch (6), the tip of the welding torch (6) moves to a certain position (for example, 2 mm) in front of the inner surface of the flux tab on the welding origin side.
) (step 5125), the current is switched to a crater current, and the welding torch (6) continues to move toward the welding origin by swinging the head (step 5126).

When the tip of the welding torch (6) reaches the welding origin position, step 5I27) determines whether or not the final layer has been welded.Step 3128); if it is not the final layer, returns to step 5107 and performs the operations described above. repeat.

Then, when it is determined that it is the final layer in the forward operation or the backward operation (step 5l17. S12g), the 8 flow supplied to the welding torch (6) is switched to the main welding current, and the swinging electric motor (12) and lifting motor are operated in reverse to reverse the welding direction (step 5129).
After n-stenopba (step 5I30), 1~
Stop moving the welding torch (6) for 2 seconds (step 5)
131), and then the current is cut off to complete the welding operation (step 5132).

Note that during the above-mentioned operation, the retracting motor (10) continues to operate, and weaving is performed by reciprocating the torch holder (5) in the X direction.

(Effect) In the present invention, the retractable shaft holding the welding torch at the tip is configured to be rotatable within a certain angle range, and when the welding torch reaches a certain distance in front of the welding end, the retractable shaft By rotating and swinging the welding torch, the welding torch is swung along the welding line in a direction in which the tip approaches the welding end, and the height is corrected by moving the welding torch up and down so that the tip approaches the welding location. When the tip of the welding torch reaches a certain distance just before the welding end, the current supplied to the torch is switched from welding current to crater current, and when the tip of the welding torch reaches the welding end, the current is supplied to the torch. The current is switched from crater current to welding current, and the direction of swing is reversed while correcting the height of the tip of the welding torch. When the welding torch position reaches the center of the swing range, swing and height correction are stopped. Since the torch position and current are controlled so that welding is performed while the torch is held in a fixed position, the welding torch casing is not obstructed by the end tab due to the welding torch swinging. In addition to being able to position the tip of the torch at the welding end without
Since the current supplied to the torch is controlled at the welding end, welding can be performed without causing defects, particularly at the end where defects are likely to occur.

[Brief explanation of the drawing]

Figure 1 is a flowchart of the method of the present invention, Figure 2 is a perspective view of the main parts of an automatic carbon dioxide arc welding machine used in the method of the present invention, Figure 3 is a partially cutaway plan view of the base, and Figure 4 is a traveling FIG. 5 is a longitudinal sectional side view of the platform portion, and FIG. 5 is a partially cutaway plan view of the elevating platform portion. Patent applicant Katayama Iron Works Co., Ltd. Figure 2 Figure 4

Claims (1)

[Claims] 1. A running section that runs left and right along a welding line to which flux tabs are fixed at both ends, an elevating section that moves up and down with respect to this running section, and an elevating section that moves up and down with respect to the running section. When welding a joint part of a steel frame using an automatic welding machine equipped with a retractable shaft that moves forward and backward, and a welding torch supported at the tip of the retractable shaft, The retracting shaft is configured to be able to rotate and swing within a certain angle range, and when the welding torch reaches a certain distance in front of the welding end, the welding torch is rotated and swung along the welding line when the welding torch reaches a certain distance in front of the welding end. At the same time, the welding torch is moved up and down so that the tip of the welding torch approaches the welding point, and the height is corrected. Then, the current supplied to the torch is switched from welding current to crater current, and when the tip of the welding torch reaches the welding end, the current supplied to the torch is switched from crater current to welding current, and the height of the welding torch tip is changed. The oscillation direction is reversed while the welding torch is being corrected, and when the attitude of the welding torch reaches the center of the oscillation range, the oscillation and height correction are stopped and the welding is performed in a constant attitude. Automatic control method for welding steel joints using an automatic welding machine