JP4995698B2 - 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

  One reason for forming a scale-like weld bead is to increase the added value of the product by improving the appearance of the joint. However, in the above-described conventional technology, the shape of the weld bead after welding construction could not be predicted, so after actually teaching the weld bead after confirming the shape, if the appearance is not good, correct the welding conditions, The so-called try and error was repeated. That is, in order to make the weld bead into the shape as intended, there has been a problem that a great number of teaching steps are required.

  Accordingly, the present invention provides a stitch pulse welding apparatus that can confirm the shape of a weld bead in advance without performing welding in accordance with the teaching result of an operator and can form the intended weld bead shape. Objective.

In order to achieve the above object, the first invention provides:
Based on welding conditions including welding current, welding voltage and welding time set in advance by operation 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 While repeatedly regenerating the arc by moving it to the arc restart point separated by a predetermined movement pitch in the welding progress direction, the scales, which are welding marks formed by one generation of the arc, are superimposed on the workpiece. In a stitch pulse welding apparatus for forming a weld bead,
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 calculator for calculating the diameter value from the welding condition database unit with the welding condition as an input,
A display processing unit for displaying shape information of the weld bead including at least the diameter value on the operation means;
A stitch pulse welding apparatus comprising:

  The second 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 the vertical direction on the welding torch side based on the diameter value and the moving pitch, The display processing unit displays the shape information including the predicted bead shape on the operation unit, and the stitch pulse welding apparatus according to the first invention.

  According to a third aspect of the present invention, there is provided a setting unit for setting the scale overlapping rate instead of the moving pitch, and the moving pitch is automatically set by inputting the overlapping rate and the diameter value when the overlapping rate is set. A stitch pulse welding apparatus according to the first or second aspect of the present invention, further comprising: a moving pitch calculation unit for calculating.

  4th invention is equipped with the scale total number calculation part which calculates the total number of the scales in the said weld bead based on the said diameter value and the said movement pitch, The said display process part is the said operation means to the said shape information containing the said total number The stitch pulse welding apparatus according to any one of the first to third aspects of the present invention.

  In a fifth aspect of the invention, the display processing unit displays any or all of the diameter value, the total number, the overlap ratio, the movement pitch, and the predicted bead shape as the shape information on the operation unit. A stitch pulse welding apparatus according to any one of the first to fourth inventions.

  According to the first invention, since the shape of the weld bead can be predicted before welding, trial work for forming an ideal weld bead is unnecessary. That is, the teaching man-hour can be reduced.

  According to the second invention, since the predicted shape of the weld bead is visually displayed, the shape recognition of the weld bead can be simplified in addition to the effect of the first invention.

  According to the third invention, the teaching of the ideal welding bead appearance is made possible by teaching the scale overlap ratio instead of the moving pitch, so that the first and second inventions are effective. In addition to the effect, the teaching man-hour can be further reduced.

  According to the fourth invention, since the total number of scales forming the weld bead is calculated, in addition to the effects exhibited by the first to third inventions, the appearance of the weld bead after welding is simply imaged. be able to.

  According to the fifth invention, as the weld bead shape information, any one or more or all of the diameter value, the total number, the overlap rate, the movement pitch, and the predicted bead shape are displayed. In addition to the effects of the invention, the appearance of the weld bead after welding can be more easily imagined.

  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, which is 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 welding conditions. Various conditions set by the setting unit 42 are input to the robot controller RC.

  The main control unit 3 includes a teaching processing unit 20 that stores and processes the welding conditions input from the setting unit 42. When the welding current, the welding voltage, the moving speed, the moving pitch, the welding time, and the cooling time, which are necessary conditions at the time of stitch pulse welding, are input from the setting unit 42, the teaching processing unit 20 receives the welding condition Tc (welding current, welding Voltage and welding time), moving speed Sp, moving pitch Mp, and cooling time Ct are stored in the hard disk 4.

  The main control unit 3 further includes a scale diameter calculation unit 22, a movement pitch calculation unit 25, a bead shape generation unit 23, a scale total number calculation unit 26, 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. When the welding current, welding voltage, moving speed, moving pitch, welding time and cooling time, which are necessary conditions for stitch pulse welding, are input from the setting unit 42 of the teach pendant TP, the diameter of the scale is determined based on these conditions. The value Sr, the predicted bead shape Bd, and the total number of scales Bn are calculated.

  First, a method for calculating the scale diameter value Sr will be described. The scale diameter calculator 22 calculates the scale diameter value Sr from the welding condition database 21 based on the welding current, welding voltage, and welding time of the input welding conditions Tc. As shown in FIG. 2, the welding condition database 21 is a database acquired in a state where representative welding current values and welding voltage values are selected, but these are internally developed as approximate curves. For example, even if an intermediate value such as a welding time of 0.3 seconds, a welding current value of 35 A, and a welding voltage value of 15 V is input as the welding condition Tc, the scale diameter value Sr can be calculated based on the approximate curve. . The calculated scale diameter value Sr is stored in the hard disk 4.

  Next, a method for calculating the 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.

  In the above description, the movement pitch Mp is input from the setting unit 42, but the scale overlap rate Lr is input instead of the shift pitch Mp, and the shift pitch is based on the scale overlap rate Lr and the scale diameter value Sr. Mp may be calculated. Hereinafter, a method of calculating the movement pitch when the scale overlap rate is input 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, the total number of scales may be calculated. Hereinafter, a method for calculating the total number of scales will be described.
The scale total number calculating unit 26 first calculates the welding length. The welding start position and the welding end position are taught in advance. The distance between them is the weld length and can be easily calculated. Then, the scale total number Bn is calculated by the following equation.

  Scale total number Bn = welding length / moving pitch + 1

  The meaning of the above “+1” is to perform welding at the welding end point even if the movement pitch is not reached at the welding end position when a remainder is generated by the calculation. The scale total number Bn is stored in the hard disk 4.

  Next, the display processing unit 24 will be described. When an instruction is input from the setting unit 42, the display processing unit 24 displays the scale diameter value Sr, the scale total number Bn, the scale overlay rate Lr, the movement pitch Mp, and the predicted bead shape Bd stored in the hard disk 4. It is displayed on the display unit 41 as information. The shape information preferably displays all the data described above, but may be any one or more. Further, it is desirable that the instruction input from the setting unit 42 is configured to be executable when the welding condition at the time of the stitch pulse is set.

  As described above, since the shape of the weld bead can be predicted before welding, trial work for forming an ideal weld bead is unnecessary. That is, the teaching man-hour can be reduced.

  Moreover, since the predicted shape of the weld bead is visually displayed, in addition to the above effects, the shape recognition of the weld bead can be simplified.

  In addition to teaching the ideal welding bead appearance by teaching the scale overlap rate instead of the moving pitch, the teaching man-hour can be further reduced in addition to the above effects. it can.

  Further, since the total number of scales forming the weld bead is calculated, in addition to the above effects, the appearance of the weld bead after welding can be easily imagined.

  In addition to the above effects, welding construction is performed because any one or more or all of the diameter value, total number, overlap rate, moving pitch, and predicted bead shape are displayed as the shape information of the weld bead. The appearance of the later weld bead can be imaged more easily.

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 scale diameter calculation unit 23 bead shape generation unit 24 display processing unit 25 movement pitch calculation unit 26 scale total number calculation unit 41 display unit 42 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 Bn Scale total number Cr Perfect circle Ct Cooling time Db Welding condition database Dr Welding direction Ew Protrusion length G Shield gas Hr Two-dimensional plane Lr Scale scale M Manipulator Mp Movement pitch P1 Arc start point RC Robot controller Sc Weld mark Sr Scale diameter Sp Travel speed 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 welding conditions including welding current, welding voltage and welding time set in advance by operation 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 While repeatedly regenerating the arc by moving it to the arc restart point separated by a predetermined movement pitch in the welding progress direction, the scales, which are welding marks formed by one generation of the arc, are superimposed on the workpiece. In a stitch pulse welding apparatus for forming a weld bead,
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 calculator for calculating the diameter value from the welding condition database unit with the welding condition as an input,
A display processing unit for displaying shape information of the weld bead including at least the diameter value on the operation means;
A stitch pulse welding apparatus comprising:   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; The stitch pulse welding apparatus according to claim 1, wherein the shape information including a predicted bead shape is displayed on the operation means.   A setting unit that sets the overlap rate of the scales instead of the moving pitch, and a movement pitch calculation unit that automatically calculates the moving pitch by inputting the overlap rate and the diameter value when the overlap rate is set. The stitch pulse welding apparatus according to claim 1 or 2, further comprising:   A scale total number calculating unit that calculates the total number of scales in the weld bead based on the diameter value and the moving pitch is provided, and the display processing unit displays the shape information including the total number on the operation means. The stitch pulse welding apparatus according to any one of claims 1 to 3.   The display processing unit displays any one or more or all of the diameter value, the total number, the overlap ratio, the movement pitch, and the predicted bead shape as the shape information on the operation unit. Item 5. The stitch pulse welding apparatus according to any one of Items 1 to 4.

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