JP4995697B2 - Stitch pulse welding equipment - Google Patents

Description

  The present invention relates to a stitch pulse welding apparatus that performs welding while minimizing the influence of heat on a thin base metal.

  The stitch pulse welding method is a welding method that minimizes the thermal effect on the base metal by controlling the heat input and cooling during welding. It is a welding method aiming at automation of thin plate welding, and it is said that the welding appearance can be improved and the amount of welding distortion can be reduced as compared with conventional thin plate welding (see, for example, Patent Document 1).

  In Patent Document 1, an arc is generated for a predetermined time in a state where the welding torch is stopped to melt the welding base material, and after the set time has elapsed, the arc is stopped and the welding torch is connected to the outer periphery of the molten portion. Means for moving to the side arc restart point is disclosed. Hereinafter, this prior art will be described.

  FIG. 5 is a view showing a conventional stitch pulse welding apparatus 51.

  The manipulator M automatically performs arc welding on the workpiece W, and includes an upper arm 53, a lower arm 54, a wrist portion 55, and a plurality of servo motors (not shown) for rotationally driving them. It is configured.

  The arc welding torch T is attached to the tip portion of the upper arm 53 of the manipulator M, and guides the welding wire 57 having a diameter of about 1 mm wound around the wire reel 56 to the welding position where the workpiece W is taught. It is. The welding power source WP supplies a welding voltage between the arc welding torch T and the workpiece W. When the workpiece W is welded, the welding wire 7 is protruded from the tip of the arc welding torch T by a desired protrusion length Ew. The length of the protruding length Ew is generally around 15 mm, but the operator adjusts it to the desired length in advance using the teach pendant TP, which will be described later, according to the groove shape of the welding location, welding conditions, etc. Is possible.

  The conduit cable 52 includes a coil liner (not shown) for guiding the welding wire 57 therein, and is connected to the arc welding torch T. Further, the conduit cable 52 supplies the electric power from the welding power source WP and the shield gas from the gas cylinder 58 to the arc welding torch T.

  The teach pendant TP as an operation means is a so-called portable operation panel, and the conditions (welding current, welding voltage, moving speed, moving pitch, welding time, and the conditions necessary for performing the operation of the manipulator M and stitch pulse welding) Cooling time) and the like. Using this teach pendant TP, the worker creates a work program in which the above conditions are set together with the operation of the manipulator M.

  The robot controller RC is for causing the manipulator M to control the welding operation, and includes a main control unit, an operation control unit, a servo driver (all not shown), and the like. Then, based on a work program taught by the operator using the teach pendant TP, an operation control signal is output from the servo driver to each servo motor of the manipulator M, and a plurality of axes of the manipulator M are rotated. Since the robot controller RC recognizes the current position based on an output from an encoder (not shown) provided in the servo motor of the manipulator M, the robot controller RC can control the tip position of the arc welding torch T. In the welded portion, stitch pulse welding is performed while repeating the welding, movement, and cooling described below.

  FIG. 6 is a diagram for explaining a state when stitch pulse welding is performed. The welding wire 57 protrudes from the tip of the arc welding torch T. The shield gas G is always blown from the arc welding torch T at a constant flow rate from the start of welding to the end of welding. Hereinafter, each state at the time of stitch pulse welding will be described.

  FIG. 4A shows a state when an arc is generated. Based on the set welding current and welding voltage, an arc A is generated between the tip of the welding wire 57 and the workpiece W, and the welding wire 57 melts to form a molten pool Y in the workpiece W. After the arc A is generated, the arc A is stopped after the taught welding time has elapsed.

  FIG. 2B shows a state after the arc is stopped. After the arc is stopped, the state after welding is maintained until the set cooling time has elapsed. That is, since the manipulator M and the arc welding torch T are stopped in the same manner as the welding state, only the shielding gas G is blown out from the arc welding torch T. It cools and solidifies.

  FIG. 3C shows a state where the arc welding torch T is moved to the next welding position. After the elapse of the cooling time, the arc welding torch T is moved to an arc restart point that is a position separated by a preset movement pitch Mp in the welding progress direction. The moving speed at this time is the set moving speed. The moving pitch is a distance adjusted so that the welding wire 57 is positioned on the outer peripheral side of the welding mark Y ′ after the molten pool Y is solidified as shown in FIG.

  FIG. 4D shows how the arc A is regenerated at the arc restart point. The weld pool Y is newly formed at the front end portion of the welding mark Y ', and welding is performed. Thus, in the stitch pulse welding apparatus 1, the state in which the arc is generated and welding is performed and the state in which the cooling and movement are performed are alternately repeated. And a welding bead is formed so that the scale which is a welding trace may overlap.

  FIG. 7 is a diagram for explaining a weld bead formed after welding. As shown in the figure, a welding mark Sc is formed at the first arc starting point P1, and a similar welding mark Sc is also formed at a re-arc starting point P2 that is separated by a moving pitch Mp toward the welding traveling direction Dr. . Further welding marks Sc are sequentially formed after the re-arc start point P3. As described above, as a result of forming the scales as welding marks so as to overlap, scale-shaped weld beads B are formed.

JP-A-6-55268

  In order to form an ideal bead shape, it is necessary to set the welding current and the welding voltage and the welding time to be an optimum combination. For example, when it is desired to reduce the diameter of the scale to about 5 mm, there is a combination of welding current, welding voltage, and welding time to make the diameter about 5 mm. For example, various combinations such as increasing the welding current and the welding voltage to set the welding time short, and conversely setting the welding current and the welding voltage low to set the welding time long can be considered. These combinations are understood only by some skilled workers, and the present situation is that other workers do not know what combination the conditions may be set.

  Furthermore, the moving pitch described above needs to be set after predicting to some extent how large the diameter of the scale will be. For example, when it is predicted that the diameter of the scale is about 5 mm, it is desirable to set the moving pitch to about 4 mm. However, when the diameter of the scale is about 3 mm as a result of correcting the welding current, the welding voltage, and the welding time, the moving pitch needs to be corrected to about 2 mm.

  That is, it is very difficult to combine the welding current and welding voltage with the welding time, and at the same time, it is necessary to set the movement pitch in conjunction with these combinations. There is a problem that it takes a lot of teaching man-hours.

  Therefore, according to the present invention, stitches in which necessary welding conditions (welding current, welding voltage, welding time) are automatically set simply by the operator specifying a desired bead shape (scale diameter, overlap ratio, etc.). An object is to provide a pulse welding apparatus.

In order to achieve the above object, the first invention provides:
Based on the welding conditions including the welding current, welding voltage and welding time set by the operating means, an arc is generated with the welding torch stopped, and after the welding time has elapsed, the arc is stopped and then the welding torch is welded. While repeatedly regenerating the arc by moving it to the arc restart point separated by a predetermined movement pitch in the direction of travel, the scales, which are welding marks formed by one occurrence of the arc, are overlapped and welded onto the workpiece. In stitch pulse welding equipment for forming beads,
A welding condition database section that stores in advance the correspondence between the welding condition and the diameter value of the scale,
A scale diameter setting unit for setting the diameter value;
A welding condition calculation unit that calculates the welding condition from the welding condition database unit using the diameter value as an input;
A stitch pulse welding apparatus comprising:

  According to a second aspect of the present invention, there is provided a scale overlapping rate setting unit for setting the scale overlapping rate instead of the moving pitch, and a movement pitch calculating unit for automatically calculating the moving pitch by inputting the overlap rate and the diameter value. And a stitch pulse welding apparatus according to the first invention.

  3rd invention is provided with the display process part which displays the said welding conditions on the said operation means, and the said display process part is the said 1 or several said welding current which the said welding condition calculation part calculated, the said welding voltage, and the said The stitch pulse welding apparatus according to the first or second invention, wherein a combination pattern of welding times is displayed on the operation means.

  A fourth invention includes a bead shape generation unit that generates a predicted bead shape on a two-dimensional plane when the weld bead is viewed from a vertical direction on the welding torch side based on the diameter value and the moving pitch, The display processing unit is a stitch pulse welding apparatus according to a third aspect, wherein the predicted bead shape is displayed on the operation means.

  In a fifth aspect of the invention, the stitch pulse welding apparatus according to the fourth aspect of the invention displays any one or more of the diameter value, the overlap ratio, and the moving pitch in addition to the predicted bead shape. It is.

  According to the first invention, the optimum welding current, welding voltage and welding time are automatically calculated by designating the diameter value of the scale which is the welding mark, so that the teaching man-hour can be reduced. it can.

  According to the second aspect of the present invention, the moving pitch is set not as an absolute value but as a relative value of the scale overlap rate, so that it is necessary to reset the moving pitch according to the correction of the scale diameter value. There is no. That is, in addition to the effect produced by the first invention, the teaching man-hour can be further reduced.

  According to the third aspect of the present invention, when a plurality of combination patterns are calculated by displaying the combination pattern of the calculated welding current, welding voltage and welding time on the operation means, the first and second aspects of the invention In addition to the effects, it is possible to select a combination pattern of optimum welding conditions. For example, the tact time can be shortened by the operator selecting a combination pattern having a short welding time.

  According to 4th invention, in addition to the effect which 1st-3rd invention show | plays by having made it display on the operation means the prediction bead shape estimated after welding construction, the bead shape after welding construction is shown. Can be visually recognized.

  According to the fifth aspect, in addition to the predicted bead shape, any one or more of the diameter value, the overlapping rate, and the moving pitch are displayed. In addition to the effects of the first to fourth aspects, Thus, the bead shape after welding can be imaged more clearly.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the invention will be described based on examples with reference to the drawings.

  FIG. 1 is a block diagram of a stitch pulse welding apparatus 1 according to the present invention. In the figure, the difference from the prior art FIG. 5 is a robot control device RC and a teach pendant TP as an operation means. In addition, the manipulator M, the welding power supply WP, the wire reel 56, the gas cylinder 58, etc. which were demonstrated in FIG. 4 are abbreviate | omitted not shown. Hereinafter, the robot controller RC and the teach pendant TP constituting the main part of the present invention will be described.

  The robot controller RC is for causing the manipulator M to control the welding operation. The robot controller RC performs the trajectory calculation of the main control unit 3 and the manipulator M as the center, and uses the calculation result as a drive signal as a drive command unit 12. The operation control unit 11 for outputting to the motor, the drive command unit 12 for outputting the servo control signal for controlling the rotation of each servo motor of the manipulator M, the hard disk 4 for storing the work program and various parameters, and the temporary calculation area RAM 5, central processing unit CPU 6, welding control unit 13 for controlling welding, and a servo driver (not shown), which are connected via a bus (not shown).

  The teach pendant TP as an operation means includes a display unit 41 that displays various information, and a setting unit 42 that sets various conditions such as a movement target position of the manipulator M and operation parameters. The setting unit 42 includes a scale diameter value setting unit 42a for setting the diameter value of the scale, and a scale overlap rate setting unit 42b for setting the scale rate of the scale. Various conditions and the like input by the setting unit 42 are input to the main control unit 3 of the robot controller RC.

  The main control unit 3 includes a teaching processing unit 20 that stores various conditions input from the setting unit 42. The teaching processing unit 20 receives the scale diameter value, the moving speed, the moving pitch, and the cooling time, which are necessary conditions at the time of stitch pulse welding, from the setting unit 42, the scale diameter value Sr, the moving speed Sp, and the moving pitch Mp. The cooling time Ct is stored in the hard disk 4.

  The main control unit 3 further includes a welding condition calculation unit 22, a movement pitch calculation unit 25, a bead shape generation unit 23, and a display processing unit 24. On the other hand, the hard disk 4 stores a welding condition database 21 in which a relationship between welding conditions (welding current, welding voltage and welding time) and a diameter value of a scale (welding mark) formed under the welding conditions is associated. Has been. The welding condition database 21 is determined in advance by a prior experiment or the like.

  FIG. 2 is a diagram illustrating an example of a welding condition database. The welding condition database 21 is accumulated by a method of recording the diameter value of the scale while changing the welding current and the welding voltage in the actual welding environment such as the thickness of the workpiece to be used, the material and the diameter value of the welding wire. Data is a database. More specifically, for example, in a welding environment where the workpiece thickness is 1 mm and the welding wire is 0.6 mm of iron, the welding time is fixed to 0.2 seconds, and the welding current and the welding voltage are changed once. The diameter value of the scale formed when the stitch pulse welding is performed is recorded. Next, the welding time is set to 0.3 seconds, for example, and the diameter value of the scale is recorded while changing the welding current and the welding voltage again. Data accumulated by repeating this series of operations is stored in advance in the hard disk 4 as the welding condition database 21. Of course, if there is a welding environment different from the above, for example, the workpiece thickness is 1 mm and the welding wire is 0.8 mm of iron, create a welding condition database for each welding environment. It is necessary to keep it.

  Next, the operation will be described. The welding condition calculation unit 22 calculates a welding current, a welding voltage, and a welding time, which are the welding conditions Tc, from the welding condition database 21 based on the input scale diameter value Sr. As shown in FIG. 2, the welding condition database 21 is a database acquired in a state where representative welding current values, welding voltage values, and welding times are selected, but these are internally approximate curves. For example, even if the scale diameter value Sr that is not registered in the database is input, the welding condition Tc can be calculated based on the approximate curve. The calculated welding condition Tc is stored in the hard disk 4. Note that the welding condition Tc may be displayed on the display unit 41 of the teach pendant TP instead of being stored in the hard disk 4 immediately after the calculation. In this case, the operator can check the displayed welding condition Tc. And it is good to comprise so that it may memorize | store in the hard disk 4 after an operator's confirmation input.

  In addition, when calculating the welding condition Tc, there may be a plurality of combination patterns of welding current, welding voltage, and welding time. In this case, it is desirable to display all the plurality of combination patterns on the display unit 41 of the teach pendant TP. In this way, the operator can select any one of the displayed combination patterns using the setting unit 42.

  The above description is based on the assumption that the moving pitch Mp is input from the setting unit 42. However, instead of the moving pitch Mp, the scale overlap rate setting unit 42b that sets the scale overlap rate Lr is provided. The movement pitch Mp may be automatically calculated based on the scale diameter value Sr. Hereinafter, the movement pitch calculation unit 25 that calculates the movement pitch Mp will be described.

  FIG. 4 is a diagram for explaining the scale overlap rate. The scale overlap rate Lr is the rate at which the scale is overlapped with the next scale. The movement pitch calculation unit 25 calculates the movement pitch Mp by the following equation.

  Movement pitch Mp = scale diameter value Sr− (scale diameter value Sr × scale overlay rate Lr)

  The calculated movement pitch Mp is stored in the hard disk 4.

  Further, a predicted bead shape may be generated and displayed on the display unit 41 of the teach pendant TP. Hereinafter, the bead shape generation unit 23 that calculates the predicted bead shape will be described.

  The bead shape generation unit 23 generates, on a two-dimensional plane, a predicted bead shape that is predicted when the weld bead is viewed on the welding torch side and from the vertical direction, based on the scale diameter value Sr and the movement pitch Mp. .

  FIG. 3 is a diagram for explaining how to generate a predicted bead shape. As shown in the figure, first, a virtual two-dimensional plane Hr is generated, and a start position P1 is defined at an appropriate coordinate position of the two-dimensional plane Hr. And an appropriate direction is determined from this starting point, and it is set as welding progress direction Dr. Then, the weld line is divided at equal intervals from the start position by the moving pitch Mp. And the prediction bead shape Bd is produced | generated by producing | generating the perfect circle Cr of diameter value Sr in all the division points P1-Pn. The number of division points may be a number that allows the operator to generate an image of the predicted bead shape Bd, for example, about 4 to 5 or 10 or more. The calculated two-dimensional plane data of the predicted bead shape Bd is stored in the hard disk 4.

  When a display instruction is issued from the setting unit 42, the display processing unit 24 displays the predicted bead shape Bd stored in the hard disk 4 on the display unit 41. Furthermore, in addition to the predicted bead shape Bd, any one or more of the scale diameter value Sr, the movement pitch Mp, and the scale overlap rate Lr may be displayed. In addition, it is desirable that the display instruction from the setting unit 42 can be input when the welding condition at the time of the stitch pulse is set, but the scale diameter value can be input even if the display instruction is not input. You may make it display automatically, when Sr, the movement pitch Mp, or the scale overlap ratio Lr is input from the setting part 42. FIG.

  As described above, since the optimum welding current, welding voltage, and welding time are automatically calculated by setting the diameter value of the scale that is the welding mark, the teaching man-hour can be reduced.

  In addition, since the movement pitch is set not as an absolute value but as a relative value such as the scale overlap rate, it is not necessary to reset the movement pitch according to the correction of the scale diameter value. That is, in addition to the above effects, the teaching man-hour can be further reduced.

  Further, by displaying the combination pattern of the calculated welding current, welding voltage and welding time on the operation means, in particular, when a plurality of combination patterns are calculated, in addition to the above effects, a combination pattern of optimum welding conditions can be selected. You can choose. For example, the tact time can be shortened by the operator selecting a combination pattern having the shortest welding time.

  In addition to the above effects, the shape of the weld bead predicted after welding is displayed on the operation means, so that the shape of the weld bead after welding can be visually recognized.

  In addition to the predicted bead shape, any one or more of the diameter value, the overlap rate, and the moving pitch is displayed as the weld bead shape information. The shape can be imaged more clearly.

1 is a block diagram of a stitch pulse welding apparatus according to the present invention. It is a figure which shows an example of a welding condition database. It is a figure for demonstrating a mode that a prediction bead shape is produced | generated. It is a figure for demonstrating the scale overlay. It is the figure which showed the conventional stitch pulse welding apparatus. It is a figure for demonstrating a state when performing stitch pulse welding. It is a figure for demonstrating the weld bead formed after welding construction.

Explanation of symbols

1 Stitch pulse welding device 3 Main control unit 4 Hard disk 5 RAM
6 CPU
7 welding wire 11 operation control unit 12 drive command unit 13 welding control unit 20 teaching processing unit 21 welding condition database 22 welding condition calculation unit 23 bead shape generation unit 24 display processing unit 25 moving pitch calculation unit 41 display unit 42 setting unit 42a scale Diameter value setting part 42b Scale overlap ratio setting part 51 Conventional stitch pulse welding device 52 Conduit cable 53 Upper arm 54 Lower arm 55 Wrist part 56 Wire reel 57 Welding wire 58 Gas cylinder A Arc Bd Predicted bead shape Cr True circle Ct Cooling time Db Welding condition database Dr Welding direction Ew Protrusion length G Shielding gas Hr Two-dimensional plane Lr Scale scale M Manipulator Mp Moving pitch P1 Arc start point RC Robot controller Sc Weld mark Sr Scale diameter T Arc welding torch Tc Welding condition TP T Chi Pendant W workpiece WP welding power supply Y melt pool Y 'welding mark

Claims (5)

Based on the welding conditions including the welding current, welding voltage and welding time set by the operating means, an arc is generated with the welding torch stopped, and after the welding time has elapsed, the arc is stopped and then the welding torch is welded. While repeatedly regenerating the arc by moving it to the arc restart point separated by a predetermined movement pitch in the direction of travel, the scales, which are welding marks formed by one occurrence of the arc, are overlapped and welded onto the workpiece. In stitch pulse welding equipment for forming beads,
A welding condition database section that stores in advance the correspondence between the diameter value of the scale and the welding conditions;
A scale diameter setting unit for setting the diameter value;
A welding condition calculation unit that calculates the welding condition from the welding condition database unit using the diameter value as an input;
A stitch pulse welding apparatus comprising:   A scale overlay setting unit for setting the scale overlay instead of the travel pitch, and a move pitch calculator for calculating the travel pitch based on the overlay ratio and the diameter value, The stitch pulse welding apparatus according to claim 1. A display processing unit for displaying the welding condition on the operation means;
The said display process part displays the combination pattern of the said welding electric current, the said welding voltage, and the said welding time which the said welding condition calculation part calculated on the said operation means, The said operation means is characterized by the above-mentioned. The described stitch pulse welding apparatus.   A bead shape generating unit that generates a predicted bead shape on a two-dimensional plane when the weld bead is viewed from a vertical direction on the welding torch side based on the diameter value and the moving pitch; 4. The stitch pulse welding apparatus according to claim 3, wherein a predicted bead shape is displayed on the operation means.   The stitch pulse welding apparatus according to claim 4, wherein the display processing unit displays at least one of the diameter value, the overlap rate, and the moving pitch in addition to the predicted bead shape.

Images