JP2006136918A - Automatic welding method for steel column - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic welding method for a steel column, which prevents the steel column from being deformed although the steel column as a workpiece remains loaded in a positioner after welded. <P>SOLUTION: After the workpiece is welded by a welding robot (step S1), the number of rotations of the workpiece to be rotated is determined on the basis of the total rotational time and rotational speed of the workpiece after welded (step S2). A plurality of teaching points per rotation of the workpiece are set (step S3). A moving time and the number of moves between one teaching point and the next teaching point are determined on the basis of the determined number of rotations of the workpiece to be rotated (step S4). The determined moving time and number of moves are set in an existing robot control program (step S5). The practicable program is transmitted to the robot controller (step S6) and the robot is started (step S7). The rotation of the positioner supporting the workpiece is ceased after the specified period of time (step S8) and the workpiece is removed from the positioner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an automatic welding method for a steel column that can prevent deformation of the steel column as a workpiece.

  Examples of the steel column for building include a column column, a pipe column, and a connecting column core. For example, JP-A-6-285637 (Patent Document 1) and JP-A-2000-79471 (Patent Document 2) are known as conventional techniques relating to such an automatic welding method for architectural steel columns.

  In Patent Document 1, the operation of a welding robot is taught in advance for a first column core having a standard shape and size, and the first data is input to the control means as the first data, and then actually subjected to welding. Second data relating to the connected column core is input to the control means, and the first data is changed based on the second data to create a first job for measurement. Based on the first job, At least one of the position, shape, and dimensions of the connecting column core to be welded to is measured, and a second job for causing the welding robot to weld the connecting column core based on the measurement result is created. Discloses an automatic welding control method for welding connected column cores. According to this method, high welding quality can be maintained even in the case of long-time welding (Patent Document 1, Claims, Paragraph 0016).

On the other hand, in Patent Document 2, when performing welding of a plurality of layers on a workpiece having a plurality of welding lines, first, the first layer welding of each welding line is sequentially performed to temporarily stop the initial layer welding state. An automatic welding method is disclosed in which welding is restarted after confirmation and the remaining weld layers are sequentially welded to each weld line. According to the automatic welding process, the first layer of high risk of being stopped halfway due to welding defects, preferentially construction for each weld line L ₁ through L _n, to be free from defects in these first layer after confirming collectively. Thus sequentially applying a welding of the remaining intermediate layer and a finishing layer for each weld line L ₁ through L _n, can significantly reduce the incidence of aborted automatically unattended operation (Patent Document 2, Claims, Paragraph 0014, etc.)

JP-A-6-285637 JP 2000-79471 A

  However, the above prior art has not been devised to prevent deformation of the workpiece to be welded, and if the workpiece must be left on the positioner for a long time after welding, the workpiece is caused by gravity. There is a problem of deformation. In particular, when automatic welding operation is started during the daytime and automatic welding operation ends at night when it is unattended, the workpiece is left on the positioner until the next morning, during which the steel column deforms. There is a problem to do.

  Depending on the size of the steel column, a long welding time is required, and welding is not completed within a fixed time, so overtime work may occur, and welding may end at midnight. In such a case, the operator is often absent, and the workpiece that has been welded cannot be immediately removed from the positioner. Therefore, it is left as it is until the morning of the next day, and the steel column is bent due to gravity during this time, and there is a problem that deformation occurs.

  FIGS. 9A and 9B are explanatory views showing a deformed state of the steel column that is left on the positioner for a long time after being welded. 9 (a) and 9 (b), a steel column 81 which is a workpiece is supported by a positioner 82 at two positions spaced apart in the longitudinal direction. In FIG. 9A, large gravity acts on the beam member 83 portion between the positioners 82, not between the positioners 82, but on the beam member 83 portion outside the positioner 82 and the tip 84 of the steel column. Deflection or deformation occurs as indicated by the broken line.

  8B, the beam member is not attached to the joint portion, but the weld joint 85 portion between the positioners 82, the joint 85 portion outside the positioner 82, not between the positioners 82, and A large gravity acts on the tip 84 of the steel column, and bending or deformation occurs as indicated by the broken line in the figure.

  The present invention has been made in view of such problems, and an automatic welding method for a steel column that does not deform the steel column even if the steel column that is a workpiece after welding is left mounted on the positioner is provided. The purpose is to provide.

  An automatic welding method for a steel column according to the present invention is an automatic welding of a steel column in which a temporarily fixed workpiece is fixed to a positioner, and the welding joint of the workpiece is automatically welded by a welding robot while rotating the positioner at a predetermined number of rotations. The method is characterized in that after the welding of the welded joint is completed, the rotation of the positioner is continued for a predetermined time at a rotational speed equal to or lower than the rotational speed at the time of welding.

  In this case, for example, the rotational speed at the time of workpiece welding in the positioner is preferably 0.5 rpm or more, and the rotational speed after the end of welding is preferably 0.1 to 0.5 rpm.

  In this case, the robot control program for the welding robot controls the rotation of the positioner based on the movement time between adjacent teaching points and the number of movements thereof, and a plurality of teachings per one rotation of the workpiece. A point is set, the movement time and the number of movements between one teaching point and the next teaching point are obtained based on the desired total rotation time and rotation speed, and the movement time and the number of movements are set in the robot control program. Then, it is preferable to control the rotation of the positioner after the end of the welding.

  According to the automatic welding method for a steel column of the present invention, by rotating the workpiece mounted on the positioner at a predetermined rotational speed even after the end of welding, the gravity always acts on the steel column as the workpiece in the same direction. Since it can avoid, the deformation | transformation by gravity of a steel column can be prevented.

  In this case, if the rotational speed at the time of workpiece welding in the positioner is 0.5 rpm or more and the rotational speed after the end of welding is 0.1 to 0.5 rpm, the load and power consumption on the positioner are the minimum necessary. The deformation of the steel column can be prevented by limiting to the limit.

  Further, when the robot control program of the welding robot is to control the rotation of the positioner based on the movement time between adjacent teaching points and the number of movements thereof, a desired total rotation time for preventing bending and The movement time and the number of movements between one teaching point and the next teaching point are obtained based on the rotation speed, and the movement time and the number of movements are set in the robot control program to rotate the positioner after the welding is completed. If this is controlled, the present invention can be applied as it is using an existing control program.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a control device used in a welding robot control method according to an embodiment of the present invention, FIG. 2 is an explanatory view showing a two-arc automatic welding device, and FIG. 3 is a bracket type steel frame to be assembled by welding. It is a perspective view which shows a column pillar.

  In FIG. 1, a positioner 1, a welding robot 2 and a welding power source 3 are controlled by a control device 4. The control device 4 is provided with a positioner control unit 5, and the positioner control unit 5 controls the rotation speed and rotation time of the positioner on which the workpiece is mounted. In addition, the control device 4 is provided with a robot body control unit 6, a robot operation calculation unit 7, and a teaching program storage unit 8, and welding is performed by the robot operation calculation unit based on the teaching program stored in the teaching program storage unit 7. An execution program for the target workpiece is created, and the welding robot is controlled by the robot body controller 6 based on the execution program.

  The control device 4 includes a welding power source control unit 9, a primary storage unit 10, a calculation unit 11, a storage unit 12, and an input device 13. The operator inputs a rotation time and a rotation speed as conditions for continuing the rotation of the workpiece after the end of welding via the input device 13. The storage unit 12 stores the input rotation time and rotation speed.

  The calculation unit 11 calculates the number of rotations of the workpiece and the movement time between teaching points described later based on the input data stored in the storage unit 12, and inputs and stores the signal in the teaching program storage unit 8. The primary storage unit 10 stores the calculation result calculated by the calculation unit 11. A welding power source control unit 9 supplies necessary power to the positioner 1, the welding robot 2, and each control unit.

  The welding robot 2 is, for example, a 6-axis vertical articulated type, and a welding torch is provided at the tip of the wrist of the tip arm. This welding robot performs an operation based on a teaching work by a teaching work input device which is a teaching pendant and an operation based on teaching program execution data created by the teaching work.

  The positioner 1 is, for example, a one-side-supported uniaxial shaft that supports two parts of a workpiece that is a steel column. The support drive member of the positioner 1 has a work clamp part that holds a work, and the work is held by the work clamp part. In response to a command from the robot control device, the positioner 1 rotates the workpiece so that the workpiece is in an appropriate welding posture with respect to the robot body.

  In FIG. 2, the robot welding apparatus is provided with two (one pair) positioners 31 and 32 and two welding robots 33 and 34. A welding robot 33 is disposed between the positioners 31 and 32, and the welding robot 34 is disposed at a position facing the welding robot 33 with the positioner 32 interposed therebetween.

  The welding robots 33 and 34 are respectively mounted on a movable carriage 35 that travels on the rail 50, and a welding wire storage container 37 and a power supply device 42 are provided on each carriage 35. Arms 40 and 41 are respectively installed at one end of the carriage 35 in the direction orthogonal to the rail 50. A torch 38 is provided at the tip of the arm 40, and the welding wire 39 wound and stored in a coil shape in the wire storage container 37 is unwound and supplied to the torch 38 via the conduit tube 36. Then, it passes through the torch 38 and is supplied to the welded portion. The welding power source device 42 is connected to the torch 38 by a cable 43 and supplies welding power to the welding wire 39 via the torch 38.

  The positioners 31 and 32 are installed so that the rotating part 45 can rotate with respect to the base 44. The rotating part 45 has a shape in which a central part is cut out in a rectangular shape, and a fixing tool 46 for fixing a work is provided on at least one pair of opposing sides in the central notch part.

  FIG. 3 is a perspective view showing a steel column column as a workpiece. In FIG. 3, the steel column 51 is preliminarily welded and assembled. Such a steel column column 51 is fixed to the rotating portion 45 of the positioner by the fixture 46 (see FIG. 2). The pair of positioners 31 and 32 is provided at a position where the notch portions thereof are aligned (overlapped) when viewed in the longitudinal direction of the steel column column 51. The fixture 46 is adjusted so that the central axes of the columns 53 coincide.

  The column 53 of the steel frame column 51 is sandwiched and supported by the positioners 31 and 32 at two positions, and four weld lines 52 between the end surface of the column 53 and the diaphragm 55 of the column core 54 are welded. In this case, the end portion (or cross section) of the column 53 is composed of four straight portions and four corner portions, and the corner portions are curved at an appropriate radius. Therefore, the weld line 52 between the end portion of the column 53 and the surface of the diaphragm 55 is composed of four straight portions and four corner portions along the outer edge of the end portion of the column 53. It becomes.

  In FIG. 3, a steel column column 51 to be welded is assembled by welding joints to four side surfaces of a column portion of a column core 54 and welding a column 53 vertically to a diaphragm 55 of the column core 54. Therefore, the joint line between the column 53 and the diaphragm 55 of the column core 54 becomes a weld line, and this weld line is, for example, 12-pass multiple welded. There are six welded joints of the steel column 51. For example, when performing 12-pass multi-layer welding, the total welding time is about 12 hours.

  Hereinafter, an operation when multi-layer welding is performed by the robot welding apparatus of the present embodiment configured as described above and the rotation of the workpiece is continued after the welding is completed will be described. FIG. 4 is an operation flow chart of the steel column automatic welding method according to the present invention. When the welding of the workpiece by the welding robot 2 is completed (step S1), an instruction as to whether or not to rotate the workpiece after the completion of welding, which is input in advance by the operator via the input device 13 as the setting unit of the control device 4, and the workpiece The number of times the workpiece is rotated is determined from the set values of the total rotation time and the rotation speed (step S2).

  Next, as shown in FIG. 5, for example, 4 teaching points 61 to 64 are set per rotation of the workpiece (every 90 degrees) (step S3). FIG. 5 is an explanatory diagram showing a robot execution program for rotating the workpiece. In FIG. 5, the steel column 51 as a work rotates counterclockwise about the rotation center 60 of the positioner 1 as a rotation axis. Four teaching points 61 to 64 are set at a rotation angle interval of 90 degrees per work rotation.

  Next, the movement time and the number of movements between each teaching point are obtained based on the number of rotations of the work obtained from the total rotation time and the rotation speed of the work (step S4). That is, the movement time and the number of movements between the teaching point 61 and the teaching point 62, the movement time and the number of movements between the teaching point 62 and the teaching point 63, the movement time between the teaching point 63 and the teaching point 64, and The number of movements, the movement time between the teaching point 64 and the teaching point 61, and the number of movements are obtained. After obtaining the movement time and the number of movements between the teaching points, the obtained movement time and the number of movements are set in the existing robot execution program (step S5).

  Next, the robot execution program is transmitted to the robot controller (step S6), and the robot is started (step S7). In this way, after the welding is completed, the positioner rotates with the workpiece under a predetermined condition for a predetermined time, for example, after the welding is completed at night, until the next morning when the operator enters work. After confirming that the rotation of the positioner has ended, or when the positioner is still rotating in the morning of the next work day, the operator stops the rotation of the positioner and then moves the steel column 51 as the workpiece to the positioner 1. To be used for the next step (step S8).

  According to the present embodiment, the steel column 51 that is the workpiece is rotated for a predetermined time based on the preset total rotation time and rotation speed even after the end of welding, so that the gravity is always in a constant direction with respect to the steel column. It is possible to prevent the steel column from being bent or deformed.

  In this embodiment, if the work rotation speed after welding is set to a rotation speed equal to or lower than the work rotation speed during welding, for example, 0.1 to 0.5 rpm, the load on the work and the positioner can be kept small. Thus, the deformation of the steel column 51 can be avoided.

  In the above embodiment, the case where the bracket type steel column column 51 is used as the workpiece has been described. However, in the automatic welding method of the steel column of the present invention, the type of workpiece is not particularly limited, and FIG. The present invention can be applied to the non-bracket type steel column column 57 (FIG. 6), the steel round pipe column 58 (FIG. 7), the steel SRC column 59 (FIG. 8), and other steel columns described in FIG.

  In the non-bracket type steel column shown in FIG. 6, there are 12 welded joints, and when performing 12-pass multi-layer welding on each welded joint, the total welding time is the bracket type steel column of FIG. It will be about 24 hours, about twice as long as the pillar.

  In this embodiment, two welding robots are used. However, the present invention is not limited to this, and the number of welding robots may be one, three, or other. In this case, the number of the positioners 1, the welding power source 3, the control device 4, etc. in FIG. 1 is set corresponding to the number of welding robots.

  The steel column automatic welding method of the present invention that can effectively prevent deformation of a steel column after the end of welding due to gravity is particularly useful in the field of automatic welding using a robot.

It is a block diagram which shows the apparatus used for the automatic welding method of the steel column which concerns on embodiment of this invention. It is a figure which shows an automatic welding apparatus. It is a perspective view which shows the steel column pillar as a workpiece | work. It is operation | movement explanatory drawing of the deformation | transformation prevention method of a steel column. It is a figure which shows the robot execution program for work rotation. It is a perspective view which shows the other steel column column as a workpiece | work. It is a perspective view which shows the other steel column column as a workpiece | work. It is a perspective view which shows the other steel column column as a workpiece | work. It is a figure which shows the problem of a prior art.

Explanation of symbols

1: Positioner 2: Welding robot 3: Welding power supply 4: Control device 5: Positioner control unit 6: Robot main body control unit 7: Robot motion calculation unit 8: Teaching program storage unit 9: Welding power source control unit 10: Primary storage unit 11 : Number of rotations, movement time between teaching points calculation unit 12: rotation time, rotation speed storage unit 13: input device 31, 32: positioner 33, 34: welding robot 35: carriage 36: jet tube 37: welding wire storage container 38 : Torch 39: Welding wire 40, 41: Arm 42: Power supply device 43: Cable 45: Rotating part 50: Rail 51: Bracketed steel column pillar 52: Welding line 53: Column 54: Column core 55: Diaphragm 57: Non Bracketed steel column 58: Steel round pipe column 59: Steel SRC column 60: Center of rotation of positioner 61-6 : Teaching point 81: Steel Column 82: Positioner 83: beam member 84: front end portion 85: weld joint

Claims (3)

  In the automatic welding method for a steel column in which a work piece temporarily fixed is fixed to a positioner and the welded joint of the work is automatically welded by a welding robot while rotating the positioner at a predetermined number of rotations, after welding of the welded joint is completed The method for automatically welding steel columns, wherein the rotation of the positioner is continued for a predetermined time at a rotation speed equal to or lower than the rotation speed during welding.   The automatic rotation of a steel column according to claim 1, wherein the rotation speed at the time of workpiece welding in the positioner is 0.5 rpm or more, and the rotation speed after the end of welding is 0.1 to 0.5 rpm. Welding method. The robot control program for the welding robot controls the rotation of the positioner based on the movement time between adjacent teaching points and the number of movements, and sets a plurality of teaching points per one rotation of the workpiece. The movement time and the number of movements between one teaching point and the next teaching point are obtained based on the total rotation time and the rotation speed, and the movement time and the number of movements are set in the robot control program and the positioner The automatic welding method for steel columns according to claim 1 or 2, wherein the rotation after the end of welding is controlled.

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