JP4521845B2 - Automatic welding method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic welding method and apparatus for measuring a cross-sectional shape of a welded joint and performing welding by selecting a target position of a welding torch and welding conditions based on the measurement result.
[0002]
[Prior art]
Construction machines such as hydraulic excavators are becoming larger in size, and the thickness of the plates that make up the structures such as arms, booms, and buckets that make up these construction machines increases and the amount of welding increases. It has become necessary.
[0003]
For example, as disclosed in JP-A-8-108275, if the work piece is a pipe, its end face can be machined with high precision to form a groove and automatically welded. It is. However, if a groove of a workpiece to be welded with a complicated outer shape that is a combination of straight lines and curves, such as a construction machine structure, is to be formed with high precision by machining, the machining cost increases. The processing cost cannot be absorbed by the welding construction cost, and the cost of the structure increases.
[0004]
For this reason, gas cutting which can keep processing cost low is adopted for processing of a groove of a large-sized workpiece having a complicated shape, although processing accuracy is inferior to machining.
[0005]
For example, an automatic welding apparatus as shown in FIG. 6 has been proposed as an apparatus for performing automatic welding of an object to be welded with inferior processing accuracy. This automatic welding apparatus includes a welding robot 1, a welding torch 2 and a sensor 3 supported by the welding robot 1, a control device 4 for controlling the welding robot 1, and a welding power source 5 that applies a required welding power to a welding portion. And a sensor control device 6 that controls the sensor 3 and a data processing device 7 that calculates the cross-sectional shape of the welded portion based on the output of the sensor 3.
[0006]
And while moving the sensor 3 along the path | route taught beforehand, the distance from the sensor 3 to the to-be-welded object 8 is measured, Based on this distance data, the data processor 7 of the welding joint of the to-be-welded object 8 is measured. A cross-sectional shape is calculated, a target position and welding conditions of the welding torch 2 are set based on the cross-sectional shape, and welding is performed by controlling the welding robot 1 and the welding power source 5 by the control device 4.
[0007]
[Problems to be solved by the invention]
However, the above-described method and apparatus are based on the premise that the weld joint of the workpiece 8 to be welded has a single shape, and it is often difficult to cope with the shapes of a plurality of types of weld joints. .
[0008]
In view of the above circumstances, the object of the present invention is to set the target position of the welding torch and welding conditions (welding current, arc voltage, welding speed) corresponding to each shape regardless of the shape of the welded joint of the workpiece. It is an object of the present invention to provide an automatic welding method and apparatus which can be selectively welded.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 of the present application measures the cross-sectional shape orthogonal to the weld line of the welded joint, and determines the welding conditions and welding torch from the obtained cross-sectional shape data of the welded joint. In the automatic welding method that performs welding by setting the target position of
A plurality of processing routines corresponding to a plurality of types of welded joints and a data table storing a plurality of welding conditions for each welded joint shape are set in advance, and the type of the welded joint is selected before the measurement, Calculate the measurement data input in time series in the selected processing routine to calculate the cross-sectional shape of the welded joint, obtain the gap size and gap center position of the weld from the cross-sectional shape of the obtained welded joint , It was determined whether or not the gap size and the gap center position of the welded portion were in a preset range, and when it was determined to be a preset range, welding was performed according to the welding conditions stored in the data table.
[0010]
The invention according to claim 2 supports a measuring device for measuring the cross-sectional shape of the welded joint, a welding torch for welding the welded joint, the welding torch and the measuring device, and has a path taught in advance. A welding robot to be moved along, a cross-sectional shape of the weld joint based on the output of the measuring device, a data processing device for calculating a target position of the welding torch and welding conditions, and an output of the data processing device In an automatic welding apparatus including a control device that controls the welding robot to perform welding, a plurality of processing routines corresponding to a plurality of types of weld joint shapes and a plurality of welding conditions for each shape of the weld joints in advance. A data storage means in which a table for storing data is set is provided, the processing routine corresponding to the shape of the designated weld joint is selected, and the measurement data input in time series is selected. Calculated in service routine to calculate the cross-sectional shape of the welded joint, determine the size and the gap center of the gap of the welded portion based on the cross-sectional shape of the resulting welded joint, the size and the gap of the gap of the weld It is determined whether or not the center position is within a preset range, and when it is determined as a preset range, welding is performed according to the welding conditions stored in the data table.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 5 show an embodiment of the present invention. FIG. 1 is a side view illustrating a part of the shape of a welded joint targeted by the present invention, and FIG. 2 is an automatic welding apparatus according to the present invention. FIG. 3 is a diagram showing an example of a table showing the correspondence between the shape of the welded joint and the sensing type number, and FIG. 4 is a diagram showing an example of a table for selecting the welding condition number corresponding to the shape of the welded joint. FIG. 5 is a flowchart showing a welding method according to the present invention, and FIG. 6 is a configuration diagram of a conventional automatic welding apparatus.
[0012]
In FIG. 1, (a) is a butt joint, in which the end faces of a pair of welding base materials 8a and 8b are butted together with a gap G and welded. Moreover, (b) is a fillet joint, and the end surface of the other welding base material 8b is butted against the upper surface of one welding base material 8a with a gap G and welded. Furthermore, (c) is a flare joint, in which the end surface of the other welding base material 8b is abutted and welded to the bent portion of one welding base material 8a or the vicinity thereof.
[0013]
When measuring the shape of these welded joints, the sensor 3 is moved in the direction of the arrow. In addition, when the gap G of each weld joint is small, good welding can be performed by setting the target position of the welding torch to the gap center position P.
[0014]
In FIG. 2, 11 is an articulated welding robot. A welding torch 12 is supported at the free end of the welding robot 11. Reference numeral 13 denotes a sensor, which is composed of a laser displacement meter, for example, and is supported on the free end of the welding robot 11 at a predetermined interval from the welding torch 12.
[0015]
A control device 14 controls the operation of the welding robot 11 to move the welding torch 12 and the sensor 13 along a route taught in advance and to transmit necessary signals. A welding power source 15 applies a welding power corresponding to a command from the control device 14 between the welding torch 12 and the workpiece.
[0016]
Reference numeral 16 denotes a sensor control device that performs on / off control of the sensor 13 based on a command from the control device 14 and relays the output of the sensor 13. A data processing device 17 calculates the cross-sectional shape of the welded joint based on the position signal from the control device 14 and the output of the sensor 13 relayed by the sensor control device 16, and welds from the calculated cross-sectional shape of the welded joint. The target position and welding conditions of the torch 12 are obtained.
[0017]
Reference numeral 18 denotes an object to be welded, which is formed by joining a plurality of welding base materials. The welded object 18 is formed with various types of welded joints shown in FIG. 1 and other types of welded joints.
[0018]
Reference numeral 19 denotes a data storage device. As shown in FIG. 3, a table of types of welded joints and processing routine numbers corresponding to the welded joints, and a size of the gap between the welded joint and the butt portion as shown in FIG. A table of corresponding welding condition numbers is stored.
[0019]
A data display device 20 displays the data stored in the data storage device 19, the measurement data of the sensor 13, or the cross-sectional shape of the welded joint calculated by the data processing device 17 as necessary. Reference numeral 21 denotes a data input device, which is used when inputting data to be stored in the data storage device 19 for inputting or changing, designating the shape of a welded joint, or the like.
[0020]
The procedure for measuring the cross-sectional shape of the workpiece to be welded with such a configuration, setting the target position of the welding torch and the welding conditions, and performing automatic welding will be described with reference to FIG.
[0021]
In advance, the welding path of the workpiece 18, the shape of the welded joint and its measurement position (for example, a plurality of locations at intervals of several tens of mm) are taught, and the sensing type number corresponding to the shape of the welded joint is set in the control device 14. Remember me.
[0022]
When welding the workpiece 18, when the welding base material 8 a and the welding base material 8 b are arranged at predetermined positions, the control device 14 operates the welding robot 11 and moves the sensor 13 to the measurement start position. (Step S1).
[0023]
When the sensor 13 is positioned at a predetermined position, a sensing type number Nj corresponding to the shape of the weld joint input at the time of teaching is transmitted from the control device 14 to the data processing device 17 (step S2).
[0024]
The data processing device 17 refers to a table of welded joint types and sensing type numbers (see FIG. 3) stored in the data storage device 19, and the sensing type number Nj received from the control device 14 exists in the table. It is determined whether or not to perform (step S3).
[0025]
If the sensing type number Nj exists in the table, the control device 14 is notified that the sensing type number Nj exists.
[0026]
When the sensing type number Nj does not exist in the table, the data processing device 17 transmits a joint type setting error message to the control device 14. The control device 14 that has received the joint type setting error stops the operation of the welding robot 1 (step S4).
[0027]
The control device 14 that has received the notification that the sensing type number Nj is present transmits a measurement command to the sensor control device 16, operates the welding robot 11, and moves the sensor 13 along a pre-taught sensing path. Let Upon receiving the measurement command, the sensor control device 16 sets the sensor 13 in the measurement state and sends the output of the sensor 13 to the data processing device 17 at predetermined time intervals. The data processing device 17 calculates distance data from the output of the sensor 13 sent in time series from the sensor control device 16, and generates information corresponding to the cross-sectional shape of the welded joint for each measurement position (step S5). .
[0028]
Further, the data processing device 17 switches the processing routine set therein to the processing routine corresponding to the sensing type number Nj (step S6).
[0029]
Then, based on the information corresponding to the cross-sectional shape of the welded joint generated from the output of the sensor 13 by the switched processing routine, the size of the gap G of the weld and the gap center position P are calculated for each measurement position ( Step S7).
[0030]
The calculated size of the gap G for each measurement position and the gap center position P are compared with a preset range to determine whether the measurement (or the installation of the workpiece 18) has been performed normally. (Step S8).
[0031]
If it is determined that the measurement is not performed normally, the data processing device 17 transmits a shape detection error message to the control device 14. The control device 14 that has received the notification of the shape detection error stops the operation of the welding robot 1 (step S9).
[0032]
When it is determined that the measurement has been normally performed, the data processing device 17 determines from the table (see FIG. 4) of the weld joint shape and gap G stored in the data storage device 19 and the corresponding welding condition number. It is determined whether or not the gap G of the weld calculated for each measurement position is within the range of the gap G set in the table (step S10).
[0033]
If any one of the gaps G at a plurality of measurement positions exceeds the gap G set in the table, the data processing device 17 transmits a gap range error error message to the control device 14. The control device 14 that has received the error outside the gap range stops the operation of the welding robot 11 (step S11).
[0034]
If the gaps G at all measurement positions are within the gap range set in the table, the data processing device 17 calculates the target position of the welding torch 12 from the gap center position P at each measurement position (step S12). ).
[0035]
The data processing device 17 transmits the welding target number corresponding to the target position of the welding torch 12 and the gap G at each calculated measurement position to the control device 14 (step S13).
[0036]
The control device 14 that has received the target position of the welding torch and the welding condition number at each measurement position corrects the welding path taught in advance according to the target position of the welding torch 12 and operates the welding robot 11 to perform welding. The torch 12 is moved to the welding start position of the corrected welding path. Then, the control device 14 selects a welding condition corresponding to the received welding condition number from the welding number and welding condition table stored in the control device 14, and transmits the welding condition to the welding power source 15. The welding power source 15 applies welding power between the welding torch 12 and the workpiece 18 based on the received welding conditions. At the same time, the control device 14 operates the welding robot 11 to move the welding torch 12 from the welding start position to the welding end position along the corrected welding path (step S14).
[0037]
At this time, even if the size of the gap G measured at each measurement position is different, welding can be performed by switching the welding conditions according to the size of the measured gap before and after each measurement position. It is possible to perform welding under optimum welding conditions according to the gap size.
[0038]
In the above embodiment, the case where the sensor 13 and the welding torch 12 are used by being attached to the free end of the welding robot 11 at a predetermined interval has been described. However, the welding torch 12 and the sensor 13 can be attached and detached. It may be configured to be replaced, or only the sensor 13 may be detachable, and the sensor 13 may be attached only during measurement.
[0039]
In the embodiment, the welding condition number and the welding condition table stored in the control device 14, the processing routine stored in the data processing device 17, and the like are stored in the data storage unit 19. If necessary, necessary data may be read from the data storage unit 19 and transmitted to the data processing device 17 and the control device 14.
[0040]
In addition, the data storage unit 19 in the embodiment can be configured by a storage unit in the control device 14 or the data processing device 17.
[0041]
In addition, the switching of the processing routine of the data processing device 17 performed in step S6 in the embodiment may be performed together with the determination of the presence / absence of the sensing type number in step S3.
[0042]
【The invention's effect】
As described above, according to the present invention, the processing routine suitable for the shape of each welded joint can be selected to calculate the shape of the welded joint, and the welding conditions considering the shape of the welded joint and the gap can be calculated. Since welding can be performed by selection, high-quality welding can be performed regardless of the shape of the weld joint.
[Brief description of the drawings]
FIG. 1 is a side view illustrating a part of the shape of a welded joint targeted by the present invention.
FIG. 2 is a configuration diagram of an automatic welding apparatus according to the present invention.
FIG. 3 is a diagram showing an example of a table showing correspondence between weld joint shapes and sensing type numbers.
FIG. 4 is a diagram showing an example of a table for selecting a welding condition number corresponding to the shape of a weld joint.
FIG. 5 is a flowchart showing a welding method according to the present invention.
FIG. 6 is a configuration diagram of a conventional automatic welding apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Articulated type welding robot, 12 ... Welding torch, 13 ... Sensor, 14 ... Control device, 15 ... Welding power supply, 16 ... Sensor control device, 17 ... Data processing device, 18 ... Object to be welded, 19 ... Data storage Device 20 ... Data display device 21 ... Data input device.

Claims (2)

In the automatic welding method of measuring the cross-sectional shape perpendicular to the weld line of the welded joint and performing welding by setting the welding conditions and the target position of the welding torch from the obtained cross-sectional shape data of the welded joint,
A plurality of processing routines corresponding to a plurality of types of welded joints and a data table storing a plurality of welding conditions for each welded joint shape are set in advance, and the type of the welded joint is selected before the measurement, Calculate the measurement data input in time series in the selected processing routine to calculate the cross-sectional shape of the welded joint, obtain the gap size and gap center position of the weld from the cross-sectional shape of the obtained welded joint , It is determined whether or not the gap size and the gap center position of the weld are within a preset range, and when it is determined as the preset range, welding is performed according to the welding conditions stored in the data table. Welding method. A measuring device for measuring a cross-sectional shape of a welded joint, a welding torch for welding a welded joint, a welding robot that supports the welding torch and the measuring device and moves along a previously taught path, and the measuring device The cross-sectional shape of the welded joint is calculated based on the output of the data, a data processing device that calculates the target position and welding conditions of the welding torch, and the welding robot is controlled based on the output of the data processing device to perform welding In an automatic welding device with a control device,
A data storage means in which a plurality of processing routines corresponding to a plurality of types of weld joint shapes and a table for storing a plurality of welding conditions for each shape of each weld joint is provided in advance, and the shape of the designated weld joint is set. The corresponding processing routine is selected, and the measurement data input in time series is calculated by the selected processing routine to calculate the cross-sectional shape of the welded joint. Based on the obtained cross-sectional shape of the welded joint , The gap size and the gap center position are obtained, and it is determined whether or not the gap size and the gap center position of the weld are within a preset range. When it is determined as the preset range, the gap is stored in the data table . An automatic welding apparatus characterized in that welding is performed according to welding conditions .

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