Laser welding method and apparatus

Abstract

The application provides a laser welding method for avoiding or reducing the problems of pits and burn-through. The method comprises the following steps: receiving a laser welding instruction and controlling a welding device to push a welding wire at a preset speed; when the welding wire is pushed for a preset time length or reaches a preset length, controlling the welding device to emit laser to melt the welding wire at a contact position between the welding wire and a workpiece to be welded. The laser welding method can melt the end of the welding wire together with the base material by the emitted laser, thereby forming a welding seam end with good appearance.

Description

Technical Field

[0001] This application relates to the field of laser welding technology, and in particular to a laser welding method and apparatus. Background Technology

[0002] Currently, laser welding is widely used. In existing laser wire-filled welding guns, the welding wire is directly fed into the welding position after it comes out of the welding wire guide. The laser emission and wire feeding start at the same time. Since the wire feeder is mostly mechanically driven, the welding wire will be delayed for a period of time before it starts to be fed forward. During this process, the laser continuously irradiates the same area, which can cause pitting and burn-through problems at the beginning of the weld. Summary of the Invention

[0003] The purpose of this application is to provide a laser welding method and apparatus to solve the problems of pitting and burn-through in the laser welding process of the prior art.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0005] A laser welding method, comprising:

[0006] Receive laser welding commands and control the welding equipment to push the welding wire at a preset speed;

[0007] When the welding wire is pushed for a preset time or a preset length, the welding equipment is controlled to emit a laser to melt the welding wire and perform laser welding at the point of contact with the workpiece to be welded.

[0008] Optionally, the preset duration is greater than or equal to the wire feeding delay duration of the welding equipment.

[0009] Optionally, before receiving the laser welding command, the method further includes:

[0010] The device receives a wire feed length adjustment command and responds to the command to adjust the wire feed length range of the welding equipment so that the end of the welding wire is within the irradiation range of the laser.

[0011] Optionally, the control of the welding equipment to emit a laser includes:

[0012] The welding equipment is controlled to start with a first laser power, and during the power ramp-up period, the laser power is increased from the first laser power to a preset laser power, and during the power fixed period, the laser is emitted according to the preset laser power.

[0013] Optionally, increasing the laser power from the first laser power to a preset laser power during the power ramp-up period includes:

[0014] The welding equipment is controlled to increase the laser power from the first laser power to the preset laser power according to a first slope during the power ramp-up period.

[0015] Optionally, the ramp duration is within 100-500ms.

[0016] Optionally, the control of the welding equipment to emit laser also includes: after welding is completed, responding to a laser stop welding command to control the welding equipment to retract the welding wire, and reducing the laser power from the preset laser power to a second laser power during the power descent period.

[0017] Optionally, reducing the laser power from the preset laser power to the second laser power during the power descent period includes:

[0018] The welding equipment is controlled to reduce the laser power from the preset laser power to the second laser power according to the second slope during the power descent period.

[0019] Optionally, the duration of the power sag period is greater than the delay duration of the retraction of the welding wire.

[0020] Optionally, after reducing the laser power from the preset laser power to the second laser power during the power descent period, the method further includes:

[0021] Control the welding equipment to stop emitting laser light.

[0022] Optionally, after controlling the welding equipment to retract the welding wire, the method further includes:

[0023] The welding equipment is controlled to push the welding wire again at a preset speed so that the tip of the welding wire is within the laser irradiation range during the next welding operation.

[0024] A laser welding apparatus, comprising:

[0025] The receiving module is used to receive laser welding commands and control the welding equipment to push the welding wire at a preset speed;

[0026] The control module is used to control the welding equipment to emit a laser to melt the welding wire at the contact point between the welding wire and the workpiece to be welded when the welding wire is pushed for a preset time or a preset welding wire length.

[0027] The beneficial effects of the solution provided in this application include:

[0028] In the laser welding solution provided in this application, during welding, a laser welding command is received and the welding equipment is controlled to push the welding wire at a preset speed; when the welding wire is pushed for a preset time or a preset welding wire length, the welding equipment is controlled to emit a laser to melt the welding wire at the contact point with the workpiece to be welded for laser welding. Since the wire feeding delay time includes at least the time during which the welding wire will be delayed before it starts to be pushed forward due to mechanical transmission, this can effectively reduce or avoid the problem of the laser coming out prematurely continuously irradiating the same area, causing pits, burn-through, and other problems. It can also make the end of the welding wire and the base material melted together by the laser, forming a weld end with a good appearance. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic flowchart of a laser welding method provided in an embodiment of this application;

[0031] Figure 2 This is a schematic diagram showing the relationship between the welding time of the laser wire feeder and the laser power and wire feed speed in some embodiments of this application. Detailed Implementation

[0032] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0033] like Figure 1 As shown, in one embodiment, a laser welding method is provided, including the following:

[0034] S10: Receives laser welding instructions and controls the welding equipment to push the welding wire at a preset speed;

[0035] S20: When the above-mentioned pushing of the welding wire reaches the preset time or preset welding wire length, control the welding equipment to emit a laser to melt the welding wire and perform laser welding at the contact point with the workpiece to be welded.

[0036] Understandably, in traditional welding processes, before welding, the welding start button is pressed, at which point laser emission and wire feeding start simultaneously. Since most welding equipment uses mechanical transmission for wire feeding, the welding wire is delayed before it begins to move forward. During this process, the laser emission position does not move, causing the laser to continuously irradiate the same area, resulting in pitting and burn-through problems at the weld's starting point. In the embodiments of this application, as... Figure 2 As shown, Figure 2 This is a schematic diagram illustrating the relationship between welding time, laser power, and wire feed speed in the laser welding method of this application. Figure 2 As can be seen, in this application, during welding, the welding gun start button of the welding equipment is first turned on to trigger the laser welding command. After receiving the laser welding command, the welding equipment is controlled to push the wire at a preset speed in response to the laser welding command. Only when the above-mentioned wire push reaches a preset time or preset wire length is the welding equipment controlled to emit a laser to perform laser welding at the contact point between the molten wire and the workpiece to be welded. In other words, the laser of the welding equipment is emitted only after the preset length or preset time. In this way, it can effectively reduce or avoid the problem of prematurely emitted laser continuously irradiating the same area, causing pits, burn-through and other problems. It can also make the end of the welding wire and the base material melted together by the emitted laser to form a weld end with a good appearance.

[0037] In one embodiment, the preset duration is greater than or equal to the wire feeding delay duration of the welding equipment. For example, if the wire feeding delay duration is 3 seconds, then the preset duration is also 3 seconds or greater than 3 seconds. This can effectively ensure the formation of a weld end with a good appearance.

[0038] In one embodiment, before receiving the laser welding command, the method further includes the following steps: receiving a wire feed length adjustment command, and responding to the wire feed length adjustment command to adjust the wire feed length range of the welding equipment so that the end of the welding wire is within the irradiation range of the laser.

[0039] In this embodiment, before welding, the wire feeding length range of the welding equipment can be adjusted so that the end of the welding wire fed by the welding equipment is within the irradiation range of the laser, which facilitates rapid welding.

[0040] In one embodiment, controlling the welding equipment to emit a laser includes:

[0041] The welding equipment is controlled to start with a first laser power, and during the power ramp-up period, the laser power is increased from the first laser power to a preset laser power. During the power fixed period, the laser is emitted according to the preset laser power.

[0042] After welding is completed, in response to the laser stop welding command, the welding equipment is controlled to retract the welding wire, and the laser power is reduced from the preset laser power to the second laser power during the power descent period.

[0043] This embodiment provides a specific method for controlling the laser emission of welding equipment. The preset laser power refers to the laser power corresponding to the normal welding state, i.e., the power used for normal welding. In this embodiment, when the welding wire is pushed for a preset time or a preset welding wire length, the welding equipment starts to emit laser with a relatively low first laser power as the starting laser power. This starting laser power is less than the preset laser power. This can effectively avoid the initial laser power being too high at the beginning of welding, which would cause the base material and welding wire to melt prematurely, resulting in the molten pool flowing forward and ultimately leading to insufficient molten metal in the weld and undercut in the base material.

[0044] In one embodiment, increasing the laser power from the first laser power to a preset laser power during the power ramp-up period includes: controlling the welding equipment to increase the laser power from the first laser power to the preset laser power at a first slope during the power ramp-up period.

[0045] In one embodiment, reducing the laser power from the preset laser power to the second laser power during the power sag period includes: controlling the welding equipment to reduce the laser power from the preset laser power to the second laser power according to a second slope during the power sag period.

[0046] In one embodiment, the ramp duration is within 100-500ms, for example, it can be 100ms, 200ms, 250ms, etc., and there is no specific limitation.

[0047] In this embodiment, a power ramp-up period is set between the initial laser power of the welding equipment and the preset laser power during normal welding. After the power ramp-up period, the laser power of the welding equipment rises to the preset laser power. In one embodiment, the rise can be linear according to a preset first slope, and the specific method is not limited. It should be noted that in traditional welding processes, the initial laser power is generally large, or even a large preset laser power from the beginning. This causes both the base material and the welding wire to melt, and the molten pool to flow forward, resulting in insufficient molten metal in the weld and undercut in the base material. However, in the embodiments of this application, as... Figure 2As shown, a power ramp-up range is set for the initial laser power of the welding equipment. For example, the laser power of the welding equipment ramps up from the initial laser power to the preset laser power within a time frame of 100-500ms. That is, during welding, the initial laser power emitted by the welding equipment is significantly lower than the laser power during normal welding. Only after the ramp-up time corresponding to the power ramp-up period does it rise to the preset laser power to achieve the power required for laser welding. It can be seen that the power lower than the normal laser power at the beginning of welding can melt the welding wire tip, but due to the relatively low power, the molten pool has poor fluidity, which will not cause undercut in the weld base material, effectively solving the problem of undercut in the weld base material. It should also be noted that the specific ramp-up time corresponding to the above power ramp-up period is only an example value and does not limit this application.

[0048] Alternatively, during power ramp-up, a gradual power ramp-up rate can be used instead of... Figure 2 The first slope shown is fixed, and the first slope can also be configured based on experience. Specific embodiments of this application are not limited.

[0049] In one embodiment, the duration of the power sag period is greater than the delay duration of the retraction of the welding wire.

[0050] In traditional welding methods, after the manual laser welding button is turned off, the laser emission and wire feeding stop immediately, unlike the delay when wire feeding is started. At this point, the welding wire is in contact with the molten pool, requiring manual lifting of the welding torch to separate the wire from the pool. However, the molten pool cools down very quickly, and manual welding cannot guarantee timely lifting, resulting in wire residue after cooling, affecting the weld appearance. Even if the wire is later manually cut, a small section remains at the end of the weld, resulting in poor appearance. In this embodiment, the welding equipment incorporates a wire retraction action at the end of the previous welding operation. Simultaneously, during the power descent period, the laser power is reduced from the preset laser power to a second laser power. Because the wire retraction is mechanically delayed, the wire does not move during this time. However, the welding equipment continues to emit laser light after receiving a stop welding command. The wire tip leaves the molten pool, and the laser continues to emit light for a certain duration, ensuring the laser melts the wire, effectively avoiding or reducing wire residue that affects the weld appearance.

[0051] Furthermore, during the laser beam reduction stage, a power descent period is set between the preset laser power and the second laser power for the welding equipment. This ensures that the welding wire tip and the base material are melted together by the emitted laser. Only after the descent period corresponding to the power descent duration does the laser power decrease to the second laser power. For example... Figure 2As shown, this embodiment not only sets a power ramp-up period between the initial laser power and the preset laser power of the welding equipment, but also sets a power ramp-down period between the preset laser power and the second laser power during the welding end stage. After welding is completed, pressing the welding gun shut-off button on the laser wire filler welding gun triggers a stop welding command, controlling the welding equipment to retract the welding wire at a preset speed. Simultaneously, the laser power of the welding equipment is controlled to decrease from the preset laser power to the second laser power. Thus, due to the mechanical transmission of the welding wire retraction, there is a delay (e.g., Figure 2 As shown in the retraction delay diagram, the welding wire does not move during this period, and the welding equipment continues to emit laser light to keep the molten pool liquid. After the welding wire is retracted, when the end of the welding wire leaves the molten pool, due to the power descent period, the welding equipment still maintains a certain laser emission time. The laser power gradually decreases during the wire retraction process, avoiding problems such as overheating and burn-through. A certain amount of power is also retained during the wire retraction process to ensure that the laser melts the welding wire. This embodiment avoids the problem of small residual sections at the tail of the weld, resulting in poor appearance.

[0052] In one embodiment, the descent time is greater than the delay time of the retraction of the welding wire. In this embodiment, the descent time of the laser is greater than the delay time of the welding wire retraction, which ensures that the welding wire can smoothly leave the molten pool.

[0053] It should be noted that during power sag, a gradual descent rate can also be used, rather than... Figure 2 The second slope shown is fixed, and the second slope can also be configured based on experience. Specific embodiments of this application are not limited.

[0054] In some embodiments, the first laser power and the second laser power may be the same, and there is no specific limitation.

[0055] In one embodiment, after reducing the laser power from the preset laser power to the second laser power during the power sag period, the method further includes controlling the welding equipment to stop emitting laser.

[0056] In this embodiment, in order to further ensure that the welding wire can leave the molten pool smoothly, the descent time of the laser should be greater than the delay time of the welding wire retraction. In this way, the welding equipment will completely stop emitting the laser after the welding wire retraction begins, which further avoids or reduces the occurrence of weld appearance defects such as heat burn-through.

[0057] In one embodiment, after controlling the welding equipment to retract the welding wire, the method further includes: controlling the welding equipment to push the welding wire again at a preset speed so that the end of the welding wire is within the laser irradiation range during the next welding operation.

[0058] Understandably, in traditional solutions, when welding the previous section of the weld is completed and re-welding is required, the welding wire is manually cut at the end of the previous section, and the wire length cannot be guaranteed. If the end of the welding wire exceeds the laser irradiation range, the end of the welding wire cannot be melted after pressing the welding button, resulting in welding wire residue. If the end of the welding wire is not long enough, the laser will directly melt the base material after pressing the welding button, easily causing burn-through. However, the welding method of this application embodiment adds compensation for the welding equipment to retract the welding wire after the previous section of the weld is completed. Specifically, after the welding wire retraction is completed, after a compensation delay period (during which there is no wire feeding compensation), the welding equipment can be controlled to push the welding wire again at a preset speed, so that the welding wire is compensated for a certain length. The welding wire compensation can ensure that when welding again, the end of the welding wire is exactly within the laser irradiation range, realizing continuous welding of multiple parts and multiple welds, and all of them can obtain welds with good appearance.

[0059] It should be noted that in practical applications, the relevant time and speed parameters of wire retraction and compensation can be written into the welding equipment, so that the welding equipment can perform the above-mentioned wire retraction and compensation time and specific wire length.

[0060] In summary, this embodiment provides a laser welding method that effectively avoids or reduces problems such as pitting, burn-through, undercut, and weld wire residue. It produces a neat and aesthetically pleasing weld with low weld height, eliminating the need for grinding. This allows it to be directly used as an appearance weld for products in manufacturing industries such as automobiles, reducing production costs and improving product appearance. Furthermore, welding processes such as laser beam ignition waiting, weld wire retraction, power ramping, and power ramping further ensure the weld appearance and quality, demonstrating high practical value and applicability.

[0061] In one embodiment, a welding product is also provided, which is a welding product obtained by the above welding method.

[0062] In one embodiment, a laser welding apparatus is also provided, comprising:

[0063] The receiving module is used to receive laser welding commands and control the welding equipment to push the welding wire at a preset speed;

[0064] The control module is used to control the welding equipment to emit a laser to melt the welding wire at the contact point between the welding wire and the workpiece to be welded when the welding wire is pushed for a preset time or a preset welding wire length.

[0065] In one embodiment, a laser welding torch is also provided for implementing the steps of the laser welding method provided in the foregoing embodiments.

[0066] It should be noted that the laser welding device can also be used to implement any of the embodiments in the foregoing method embodiments. For details, please refer to the foregoing method embodiments, which will not be repeated here.

[0067] The above are merely preferred embodiments of this application and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser welding method, comprising: Receive laser welding commands and control the welding equipment to push the welding wire at a preset speed; When the welding wire is pushed for a preset time, the welding equipment is controlled to emit a laser to melt the welding wire and perform laser welding at the point of contact between the welding wire and the workpiece to be welded. The preset duration is greater than or equal to the wire feeding delay duration of the welding equipment; The control of the welding equipment to emit laser includes: The welding equipment is controlled to start with a first laser power, and during the power ramp-up period, the laser power is increased from the first laser power to a preset laser power at a first slope. During the power fixed period, the laser is emitted at the preset laser power. After welding is completed, in response to the stop welding command, the welding equipment is controlled to retract the welding wire, and during the power descent period, the laser power is reduced from the preset laser power to the second laser power according to the second slope.

2. The laser welding method as described in claim 1, characterized in that, Before receiving the laser welding command, the method further includes: The device receives a wire feed length adjustment command and responds to the command to adjust the wire feed length range of the welding equipment so that the end of the welding wire is within the irradiation range of the laser.

3. The laser welding method as described in claim 1, characterized in that, The power ramp-up period is within 100-500ms.

4. The laser welding method as described in claim 1, characterized in that, The duration of the power descent period is greater than the delay duration of the retraction of the welding wire.

5. The laser welding method as described in claim 1, characterized in that, After reducing the laser power from the preset laser power to the second laser power, the method further includes: Control the welding equipment to stop emitting laser light.

6. The laser welding method as described in claim 1, characterized in that, After controlling the welding equipment to retract the welding wire, the method further includes: The welding equipment is controlled to push the welding wire again at a preset speed so that the tip of the welding wire is within the laser irradiation range during the next welding operation.

7. A laser welding apparatus for implementing the method as described in any one of claims 1-6, the apparatus comprising: The receiving module is used to receive laser welding commands and control the welding equipment to push the welding wire at a preset speed; The control module is used to control the welding equipment to emit a laser to melt the welding wire at the contact point between the welding wire and the workpiece to be welded when the above-mentioned wire feeding delay time reaches the preset time. The preset time is greater than or equal to the wire feeding delay time of the welding equipment. The control of the welding equipment to emit laser includes: The welding equipment is controlled to start with a first laser power. During the power ramp-up period, the welding equipment is controlled to increase the laser power from the first laser power to a preset laser power according to a first slope. During the power fixed period, the laser is emitted according to the preset laser power. After welding is completed, in response to the stop welding command, the welding equipment is controlled to retract the welding wire and, during the power ramp-down period, the laser power is controlled to decrease from the preset laser power to a second laser power according to a second slope.

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