Swing welding method for inhibiting welding wave deformation of thin plate

Abstract

The invention provides a swing welding method for inhibiting wave deformation in thin plate welding, which comprises the following implementation steps of: positioning and clamping two thin-wall plates, setting a welding center line as a swing center line of a swing welding track, and setting swing welding swing width W, swing welding edge current and swing welding center current, the welding current in the welding process is changed along with the change of the distance between the position of the tail end of the welding gun electrode and the swing welding center line, and the welding current is lower when the welding gun electrode is closer to the swing welding center line, so that the heat input of the area close to the welding center line is accurately controlled, the thermal stress accumulation of the related area is reduced, and the welding quality is improved. And the wave deformation of the related area after welding is inhibited.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a weaving welding method for suppressing wave deformation of thin plate welding. Background Art

[0002] In the practical application of welding technology, thin plate welding has always been a critical and complex technical field, and the wave deformation problem has been a major challenge that has long plagued the development of the industry.

[0003] During the welding process, when the weld expands due to heat, the surrounding relatively low-temperature thin plate area will restrict the expansion of the weld. The interaction between this thermal expansion and constraint produces uneven stress inside the plate. As welding continues, these stresses continue to accumulate and redistribute. When the stress exceeds the critical value that the plate can withstand, the plate will become unstable and show a wavy deformation. Because of its thin thickness, thin plate materials have low bending stiffness and relatively weak ability to resist deformation. Therefore, the possibility and degree of wavy deformation are greater than that of medium and thick plates.

[0004] The existing swing welding technology can reduce the wave deformation of the plate near the welding center line to a certain extent by spatially dispersing the heat input near the plate welding center line. However, it is still difficult to completely suppress the wave deformation of the plate for thinner plates, resulting in the size and shape of the workpiece after welding not meeting the standards. For this reason, it is often necessary to control the wave deformation by reducing the weld length and welding in multiple sections, which is often not feasible in situations where there are requirements for connection strength or welding sealing is required. In a large number of applications, a welding method with stronger adaptability and better wave deformation suppression effect is urgently needed to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to overcome the above problems and provide a swing welding method for suppressing the wave deformation of thin plate welding, so as to effectively reduce the wave deformation generated during thin-wall welding and improve the quality of thin-wall welding.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A weaving welding method for suppressing wave deformation of thin plate welding comprises the following steps:

[0008] Step S10, positioning and clamping two thin-walled plates, and determining a welding center line between the two plates;

[0009] Step S20, taking the welding center line as the swing center line of the swing welding trajectory;

[0010] Step S30, setting the weaving welding width W, the weaving frequency, the weaving welding edge current I1 and the weaving welding center current I2, wherein the weaving welding edge current I1 is the welding current when the end of the welding gun electrode swings to the maximum distance from the weaving welding center line during the weaving welding process, and the weaving welding center current I2 is the welding current when the end of the welding gun electrode swings to the weaving welding center line, and I1>I2;

[0011] Step S40, perform oscillating welding of thin-walled plates, and make the welding current Ix during the welding process change in response to the change of the distance s between the position of the end of the welding gun electrode and the center line of the oscillating welding, and the smaller the distance s between the end of the welding gun electrode and the center line of the oscillating welding, the smaller the welding current Ix, and the range of Ix is I2≤Ix≤I1.

[0012] During welding, the closer the plate is to the welding centerline, the greater the heat input it receives. The greater the temperature gradient during the welding process and the cooling after the welding is completed, the greater the thermal stress it receives, resulting in a greater tendency for wave deformation. Oscillating welding spatially disperses the heat input near the welding centerline of the plate. In combination with the non-constant current heat input method, the heat input in the area near the welding centerline can be more accurately controlled. On the other hand, compared with the constant current oscillating welding method of dispersing welding heat, the above non-constant current oscillating welding method of dispersing heat input can use a smaller oscillation width to achieve the same effect of controlling plate deformation, which has a positive effect on reducing weld width, improving welding appearance, and increasing welding speed.

[0013] Preferably, the welding current Ix in the welding process in step S40 changes in response to the change of the distance s between the position of the welding gun electrode end and the weaving welding center line, and the relationship between the welding current Ix and the distance s between the welding gun electrode end and the weaving welding center line can be a linear proportional relationship or a trigonometric function relationship according to the plate welding characteristics;

[0014] When Ix and s are in a linear proportional relationship, Ix and s satisfy the following quantitative relationship:

[0015]

[0016] When Ix and s are in a trigonometric relationship, Ix and s satisfy the following quantitative relationship:

[0017]

[0018] Where W is the swing width, I1 is the edge current of the swing welding, and I2 is the center current of the swing welding.

[0019] Preferably, the oscillation trajectory of the welding gun electrode may be a sawtooth shape, a crescent shape, a perfect circle shape or a trigonometric function curve shape.

[0020] Preferably, the thickness of the welded thin plates is less than or equal to 3 mm.

[0021] Preferably, during the weaving process, when the end of the welding gun electrode swings to the weaving center line, the angle between the welding gun and the welding plate is 90°, and when the end of the electrode swings to the side with the largest distance from the weaving center line, the setting range of the angle between the welding gun and the plate is 55°.

[0022] -85°, when welding to the other side which is the farthest from the center line of the welding, the setting range of the angle between the welding gun and the plate is 95°-125°.

[0023] Preferably, the setting range of the weaving edge current I1 is 10-200A, the setting range of the weaving center current I2 is 20%-90% of the welding current I1, and the setting range of the welding speed is less than or equal to 150 cm / min.

[0024] Preferably, a weaving welding system for suppressing wavy deformation in thin plate welding using the above-mentioned weaving welding method for suppressing wavy deformation in thin plate welding comprises a robot, a welding gun, a welding power supply and a PLC controller, wherein the execution end of the robot is fixedly connected to the welding gun, so that the welding gun can achieve multi-free movement driven by the robot; the electrode of the welding gun outputs the welding current supplied by the welding power supply; the robot, the welding power supply and the PLC controller are electrically connected, and during the welding process, the robot calculates the distance s between the electrode end of the welding gun and the welding center line in real time based on its own real-time point position information and posture information, and sends it to the PLC controller in real time; the PLC controller calculates the welding current value Ix to be output at the current moment based on the quantitative relationship between the preset distance s and the welding current value Ix, and sends it to the welding power supply; the welding power supply adjusts the output welding current in real time based on the welding current value Ix received in real time from the PLC controller, thereby realizing the weaving welding process for suppressing wavy deformation in thin plate.

[0025] Preferably, the welding power source has the function of receiving input variables in real time and controlling the welding current accordingly. The received input variables may be in the form of analog quantities or digital quantities.

[0026] The beneficial effects of the present invention are as follows:

[0027] The present invention provides a swing welding method for suppressing the wave deformation of thin plate welding. The method determines the welding center line between two plates, plans the swing welding trajectory with the welding center line as the swing welding center line, sets the swing welding edge current and the swing welding center current, and changes the welding current in the swing welding process in response to the change in the distance between the position of the welding gun electrode and the welding center line. Different welding heat is input to areas with different welding deformation degrees at different distances from the welding center line, thereby realizing precise control of the heat input to the area near the welding center line, thereby reducing the thermal stress accumulation in the relevant area, and effectively suppressing the wave deformation of the relevant area after welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A flow chart of a weaving welding method for suppressing wave deformation of thin plate welding provided by the present invention;

[0029] Figure 2 A schematic diagram showing a linear proportional relationship between the distance of the swing position from the swing welding center line and the welding current in the swing welding method for suppressing the wave deformation of thin plate welding provided by the present invention;

[0030] Figure 3 A schematic diagram of the trigonometric relationship between the distance of the swing position from the swing welding center line and the welding current in the swing welding method for suppressing the wave deformation of thin plate welding provided by the present invention;

[0031] Figure 4 A schematic diagram of different shapes of oscillation trajectories in the oscillating welding method for suppressing wave deformation of thin plate welding provided by the present invention;

[0032] Figure 5 The schematic diagram of the weaving welding system for suppressing the wave deformation of thin plate welding provided by the present invention;

[0033] a-sawtooth shape, b-crescent shape, c-perfect circle, d-trigonometric function curve shape. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments given here are only used to illustrate and explain the present invention, and cannot be used to limit the present invention.

[0035] It should be noted that many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention may also have other implementations and variations thereof. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0036] like Figures 1 to 5 As shown, a weaving welding method for suppressing wave deformation of thin plate welding includes the following steps:

[0037] Step S10, positioning and clamping two thin-walled plates, and determining a welding center line between the two plates;

[0038] Step S20, setting the welding center line as the center of the weaving welding track;

[0039] Step S30, setting the weaving welding width W, the weaving frequency, the weaving welding edge current I1 and the weaving welding center current I2, wherein the weaving welding edge current I1 is the welding current when the end of the welding gun electrode swings to the maximum distance from the weaving welding center line during the weaving welding process, and the weaving welding center current I2 is the welding current when the end of the welding gun electrode swings to the weaving welding center line, I1>I2;

[0040] Step S40, perform oscillating welding of thin-walled plates, and make the welding current Ix during the welding process change in response to the change of the distance s between the position of the end of the welding gun electrode and the center line of the oscillating welding, and the smaller the distance s between the end of the welding gun electrode and the center line of the oscillating welding, the smaller the welding current Ix, and the range of Ix is I2≤Ix≤I1.

[0041] Preferably, the welding current Ix in the welding process in step S40 changes in response to the change of the distance s between the position of the welding gun electrode end and the weaving welding center line, and the relationship between the welding current Ix and the distance s between the welding gun electrode end and the weaving welding center line can be a linear proportional relationship or a trigonometric function relationship according to the plate welding characteristics;

[0042] When Ix and s are in a linear proportional relationship, Ix and s satisfy the following quantitative relationship:

[0043]

[0044] When Ix and s are in a trigonometric relationship, Ix and s satisfy the following quantitative relationship:

[0045]

[0046] Where W is the swing width, I1 is the edge current of the swing welding, and I2 is the center current of the swing welding.

[0047] Example 1

[0048] The Fanuc brand M-10iD / 12 series robot, Funis RCU5000i welding power source, and Siemens S200 series PLC controller are used to form a weaving welding system to suppress the wave deformation of thin plate welding. According to the process characteristics and production requirements, the welding speed is set to 60cm / min, the weaving welding trajectory adopts a crescent shape, and the welding current Ix uses a linear proportional relationship with the distance s between the swing position and the swing center line. The swing frequency is set to 90 times / min, the swing width is 4mm, and when the end of the welding gun electrode swings to one side of the maximum distance from the swing welding center line, the angle between the welding gun and the plate is 75° and the other side is 105°. The weaving edge current is 120A and the weaving center current is 90A. During the swinging process of the welding gun, the welding power source receives the 16-bit digital current value Ix sent by the PLC controller in real time, and controls the output welding current to change back and forth between 90A and 120A, so that the plate near the welding center line will not be over-melted, and the thermal stress caused by uneven thermal expansion is reduced, thereby reducing the degree of wave deformation. At the same time, the 90A swing welding center current can still ensure the effective fusion of the weld, and there will be no defects of unfused welds. After welding, the weld quality is good, the plate is flat, and there is no obvious deformation.

[0049] Example 2

[0050] The same hardware composition as in Example 1 was used to weld a stainless steel sheet with a thickness of 1.5 mm using the swing welding system for suppressing the wave deformation of thin plate welding. The welding speed, swing welding frequency, swing welding trajectory shape, and the quantitative relationship between the welding current and the swing position were all the same as in Example 1. The swing width was set to 3 mm. When the end of the welding gun electrode was swung to the maximum distance from the swing welding center line, the angle between the welding gun and the plate was 80° and the other side was 100°. The swing welding edge current was 90 A. The 1.5 mm thin plate has a lower ability to resist deformation. The area near the welding center line has a greater tendency to deform due to the concentration of thermal stress during the welding process. Therefore, in order to suppress this deformation trend, the swing welding center current was set to 60 A with a lower current intensity under the premise of sufficient formation of the molten pool, which is equivalent to 66% of the swing welding edge current, and more effectively suppressed the wave deformation extending from the weld to both sides. After welding, the weld quality was good, the plate was flat, and there was no obvious deformation.

[0051] Example 3

[0052] The same hardware composition as in Example 2 is used to weld an aluminum alloy thin plate with a thickness of 1.5 mm using the oscillation welding system for suppressing wave deformation in thin plate welding. The quantitative relationship between the welding current and the oscillation position uses a trigonometric function relationship to more effectively control the heat input near the center line, and it is easier to select appropriate welding parameters to achieve good weld quality and a smooth plate effect.

[0053] It should be understood that the above-mentioned embodiments are multiple embodiments of the present invention, and there are many other embodiments and variations thereof based on the present invention; the variations and modifications made by ordinary technicians in this industry through the present invention without making pioneering innovations all fall within the scope of protection of the present invention.

Claims

1. A weaving welding method for suppressing the wave deformation of thin plate welding, characterized in that: The following steps are involved: Step S10, positioning and clamping two thin-walled plates, and determining a welding center line between the two plates; Step S20, taking the welding center line as the swing center line of the swing welding trajectory; Step S30, setting the weaving welding width W, the weaving frequency, the weaving welding edge current I1 and the weaving welding center current I2, wherein the weaving welding edge current I1 is the welding current when the end of the welding gun electrode swings to the maximum distance from the weaving welding center line during the weaving welding process, and the weaving welding center current I2 is the welding current when the end of the welding gun electrode swings to the weaving welding center line, and I1>I2; Step S40, perform oscillating welding of thin-walled plates, and make the welding current Ix during the welding process change in response to the change of the distance s between the position of the end of the welding gun electrode and the center line of the oscillating welding, and the smaller the distance s between the end of the welding gun electrode and the center line of the oscillating welding, the smaller the welding current Ix, and the range of Ix is I2≤Ix≤I1.

2. The weaving welding method for suppressing the wave deformation of thin plate welding according to claim 1, characterized in that: The welding current Ix in the welding process in step S40 changes in response to the change in the distance s between the position of the end of the welding gun electrode and the center line of the weaving welding. The relationship between the welding current Ix and the distance s between the end of the welding gun electrode and the center line of the weaving welding can be a linear proportional relationship or a trigonometric function relationship according to the welding characteristics of the plate; When Ix and s are in a linear proportional relationship, Ix and s satisfy the following quantitative relationship: When Ix and s are in a trigonometric relationship, Ix and s satisfy the following quantitative relationship: Where W is the swing width, I1 is the edge current of the swing welding, and I2 is the center current of the swing welding.

3. The weaving welding method for suppressing the wave deformation of thin plate welding according to claim 1, characterized in that: The oscillation trajectory of the welding gun electrode can be a sawtooth shape, a crescent shape, a perfect circle or a trigonometric function curve shape.

4. The weaving welding method for suppressing the wave deformation of thin plate welding according to claim 1, characterized in that: The thickness of the welded thin plate is less than or equal to 3mm.

5. The weaving welding method for suppressing the wave deformation of thin plate welding according to claim 1, characterized in that: During the weaving welding process, when the end of the welding gun electrode swings to the weaving welding center line, the angle between the welding gun and the welding plate is 90°. When the end of the electrode swings to the side with the largest distance from the weaving welding center line, the setting range of the angle between the welding gun and the plate is 55°-85°. When welding to the other side with the largest distance from the weaving welding center line, the setting range of the angle between the welding gun and the plate is 95°-125°.

6. The weaving welding method for suppressing the wave deformation of thin plate welding according to claim 1, characterized in that: The setting range of the weaving welding edge current I1 is 10-200A, the setting range of the weaving welding center current I2 is 20%-90% of the weaving welding edge current I1, and the setting range of the welding speed is less than or equal to 150cm / min.

7. A weaving welding system for suppressing wave deformation in thin plate welding, adopting the weaving welding method for suppressing wave deformation in thin plate welding according to any one of claims 1 to 6, characterized in that: The invention comprises a robot, a welding gun, a welding power source and a PLC controller, wherein the execution end of the robot is fixedly connected to the welding gun so that the welding gun can realize multi-free movement under the drive of the robot; the electrode of the welding gun outputs the welding current supplied by the welding power source; the robot, the welding power source and the PLC controller are electrically connected, and during the welding process, the robot calculates the distance s between the electrode end of the welding gun and the welding center line in real time according to its own real-time point information and posture information, and sends the calculated distance s to the PLC controller in real time; the PLC controller calculates the welding current value Ix to be output at the current moment according to the quantitative relationship between the preset distance s and the welding current value Ix, and sends the calculated distance s to the welding power source; the welding power source adjusts the output welding current in real time according to the welding current value Ix received from the PLC controller in real time, so as to realize the swing welding process of suppressing the wave deformation of the thin plate.

8. The oscillating welding system for suppressing wave deformation of thin plate welding according to claim 7, characterized in that: The welding power source has the function of receiving input variables in real time and controlling the welding current accordingly. The received input variables may be in the form of analog quantities or digital quantities.

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