A spot welding electrode head and welding process

Abstract

The present invention provides a laser spot welding device, which includes a welding tongs. Each of the upper and lower arms of the welding tongs is provided with a clamping mechanism composed of a clamping barrel, a static pressure head, a lead screw, and a laser emitter. The laser irradiation point of the laser emitter is located at the bottom of the clamping barrel. The lead screw of the static pressure head on the upper arm is fixedly connected to a driving motor, and the lead screw of the static pressure head on the lower arm is fixedly connected to a driving motor. A driving cylinder is provided on the lower arm or the upper arm of the welding tongs. When the welding tongs are in a clamped state, the two static pressure heads move towards each other. It can achieve uniform heating in the solder joint area, effectively avoiding problems such as burn-through, welding detachment, and false soldering, and is applicable to the welding work of various materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of automotive welding, and particularly relates to a spot welding electrode head of a spot welding gun and a welding process. Background Art

[0002] Resistance spot welding is widely used in automotive body welding and is also the main welding method in body manufacturing. Since the electrode head of the welding gun is spherical, the heat is unevenly distributed in the solder joint area during the welding process, and welding quality problems such as burn-through and false welding are likely to occur. Especially with the application of lightweight materials in modern automotive manufacturing technology, requirements such as high welding efficiency, small deformation, and stable quality need to improve the current resistance spot welding method. In particular, in modern manufacturing and body materials using new materials, due to the influence of the oxide layer conductivity of aluminum alloy on the welding temperature of the welding material. Therefore, intelligent, low-cost, and high-efficiency equipment is required for automotive welding. Summary of the Invention

[0003] In view of the above technical problems, the first aspect of the present invention provides a spot welding electrode head of a spot welding gun, including a welding gun. Each of the upper and lower arms of the welding gun is provided with a clamping mechanism. The clamping mechanism includes a clamping barrel. A static pressure head is arranged in the clamping barrel, and a lead screw is arranged at the end of the static pressure head. A laser emitter is also arranged in the clamping barrel, and the laser irradiation point of the laser emitter is located at the bottom of the clamping barrel. The lead screw of the static pressure head on the upper arm of the welding gun is fixedly connected to a driving motor, and the lead screw of the static pressure head on the lower arm of the welding gun is fixedly connected to a driving motor. A cavity is arranged in the welding gun, and a driving cylinder is arranged on the lower arm or the upper arm of the welding gun. The driving cylinder communicates with the cavity inside the welding gun. The piston of the driving cylinder is fixed to the clamping barrel and the driving motor or the driving motor inside the clamping barrel. When the welding gun is in a clamping state, the two static pressure heads move towards each other.

[0004] On the other hand, the present invention provides a welding process, which uses the spot welding electrode head of the present invention and includes the following steps:

[0005] Starting step After the welding point of the plate to be welded is placed between the two arms of the welding gun, the laser spot welding equipment is turned on;

[0006] Pre-pressing step The driving cylinder is turned on, and the piston (10) moves and drives the pressing mechanism on the lower arm or the upper arm of the welding gun to move towards the pressing mechanism of the other arm until the plate is clamped;

[0007] Heating step After the laser emitter is turned on, the laser beam parameters of the two laser emitters are adjusted respectively;

[0008] Pressing step The driving motor and the driving motor drive the static pressure heads to move towards each other;

[0009] After the cooling step closes the laser emitter, move the static heads away from each other, and maintain the pressure of the driving cylinder to lower the temperature of the welding point.

[0010] The beneficial technical effects of the present invention include: the heat is evenly distributed within the solder joint area, effectively avoiding problems such as burn-through, de-soldering, and false soldering, and being applicable to welding work of various materials, for example, being able to achieve welding of dissimilar metals with large differences in thermal conductivity and melting point. Description of the Drawings

[0011] Figure 1 : Schematic diagram of the device structure of an embodiment;

[0012] Figure 2 : Schematic diagram of the partial structure of an embodiment (contact surface between the static head 013 and the solder joint);

[0013] Figure 3 : Laser spot welding process flow of some embodiments. Detailed Embodiments

[0014] The following embodiments further illustrate the content of the present invention, but should not be construed as a limitation to the present invention. Without departing from the spirit and essence of the present invention, modifications or substitutions made to the methods, steps, or conditions of the present invention all fall within the scope of the present invention.

[0015] Some embodiments of the device include a C-shaped welding tong 06 as Figure 1-2 shown. Each of the upper and lower arms of the welding tong 06 is provided with a clamping mechanism. The clamping mechanism includes clamping barrels 02 and 012. Static heads 03 and 013 are provided inside the clamping barrels 02 and 012, and a lead screw 04 is provided at the end of the static head; a laser emitter 01 is also provided inside the clamping barrel, and the laser irradiation point of the laser emitter is located at the bottom of the clamping barrel; the lead screw 04 of the static head 03 on the upper arm of the welding tong is fixedly connected to a transmission motor 05, and the lead screw of the static head on the lower arm of the welding tong is fixedly connected to a driving motor 011;

[0016] A cavity is provided inside the welding tong 06. A driving cylinder 09 is provided on the lower arm or the upper arm of the welding tong (in a preferred embodiment, the driving cylinder is only provided on the lower arm), and the driving cylinder communicates with the cavity inside the welding tong; the piston of the driving cylinder is fixed to the clamping barrel and the driving motor. When the welding tong is in a clamped state, the two static heads move towards each other.

[0017] The control circuit of the device in some embodiments includes a main controller, a storage module, a motor drive module, a cylinder drive module, a power supply module, and an interface module that are electrically connected to the main controller. The motor drive module is electrically connected to the drive motor and the transmission motor; the interface module 07 includes an interaction interface 071 and an operation interface 072. The main controller communicates with the upper computer through the industrial Internet. It should be noted that the specific implementation of the above control circuit is achieved based on the conventional technical means of those skilled in the art, and the present invention does not make specific limitations.

[0018] In some preferred embodiments, the working surfaces of the two static heads in contact with the welding surface are provided with grooves or protrusions in the shape of concentric rings.

[0019] Preferably, the laser emitter is a quasi-continuous fiber laser, specifically, a laser such as model YLR-150 / 1500-QCW-AC. In the pulsed mode with an average power of 150 watts and the continuous wave (CW) mode with an average power of 250W, the generated pulse can reach 15J, while most micro-welding applications require less than 5J.

[0020] The process of a welding process is as Figure 3 , based on any one of the above embodiments, the electrode head of the spot welding tongs performs the following steps:

[0021] Starting step After placing the welding point of the plate to be welded between the two arms of the welding tongs, turn on the laser spot welding device;

[0022] Pre-pressing step Turn on the driving cylinder, and the cylinder piston moves to drive the pressing mechanism of the lower arm or the upper arm of the welding tongs to move towards the pressing mechanism of the other arm until the plate is clamped;

[0023] Heating step After the laser emitter is turned on, adjust the laser beam parameters of the two laser emitters respectively;

[0024] Pressing step The drive motor and the transmission motor drive the static heads to move towards each other;

[0025] Cooling step After turning off the laser emitter, move the static heads away from each other, and keep the pressure of the driving cylinder to lower the temperature of the welding point.

[0026] In the heating step, by controlling the release amount of the heating energy respectively, the phenomenon of burn-through is avoided. Based on the heating with double laser heads, the adaptability of welding is improved, and the welding machine can adapt to different thickness plates and different materials (with weldability).

[0027] More specific embodiments: in the above pressurization step, the static pressure heads located on the upper and lower sides of the plate continuously apply pressure. When the plate is made of aluminum alloy, due to the conductivity of the aluminum alloy oxide layer affecting the welding temperature of the welding material, the welding method adopted by the present invention can effectively prevent this phenomenon from occurring; when resistance spot welding is used to weld easily oxidized metals, due to the presence of the oxide layer, oxides accumulate inside the weld spot, becoming welding defects. In the holding pressure step of the present invention, the concentric ring-shaped groove can break the oxide film layer located on the surface of the weld spot.

[0028] In the startup step of some embodiments, it further includes the step of selecting an automatic mode or a manual mode; in the automatic mode, the main controller obtains the operation instructions and process parameters sent by the upper computer from the interaction interface; the process parameters include cylinder pressure parameters, static pressure head pressure parameters, and laser beam parameters, and the laser beam parameters include the intensity, frequency, and working time of the laser beam. In the manual mode, the main controller obtains the preset process parameters from the memory.

[0029] Set the process parameters according to the data of the plate including thickness, metallurgical properties, mechanical properties, and the refractive and reflective properties of the material to the laser.

[0030] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A spot welding electrode head of a welding tong, characterized in that, It includes a welding tong (06), and each of the upper and lower arms of the welding tong (06) is provided with a clamping mechanism. The clamping mechanism includes clamping barrels (02, 012), and a static pressure head (03, 013) is arranged in the clamping barrels (02, 012). A lead screw (04) is arranged at the end of the static pressure head (03, 013); a laser emitter (01) is also arranged in the clamping barrel, and the laser irradiation point of the laser emitter (01) is located at the bottom of the clamping barrel; the lead screw (04) of the static pressure head (03) on the upper arm of the welding tong is fixedly connected to a transmission motor (05), and the lead screw of the static pressure head on the lower arm of the welding tong is fixedly connected to a driving motor (011); a cavity is arranged in the welding tong (06), and a driving cylinder (09) is arranged on the lower arm or the upper arm of the welding tong. The driving cylinder (09) communicates with the cavity inside the welding tong (06); the piston (10) of the driving cylinder is fixed to the clamping barrel and the driving motor (011) or the transmission motor inside the clamping barrel. When the welding tong is in the clamping state, the two static pressure heads move towards each other.

2. The electrode head of the spot welding tongs according to claim 1, characterized in that, It further includes a control circuit, and the control circuit includes a main controller, a storage module, a motor driving module, a cylinder driving module, a power supply module, and an interface module that are electrically connected to the main controller. The motor driving module is electrically connected to the driving motor and the transmission motor; the interface module (07) includes an interaction interface (071) and an operation interface (072).

3. The electrode head of the spot welding tongs according to claim 2, wherein The main controller communicates with the upper computer through the industrial Internet.

4. The electrode head of the spot welding tongs according to claim 1, characterized in that, On the working surfaces where the two static pressure heads contact the welding surface, there are grooves or protrusions in the shape of concentric rings.

5. The electrode head of the spot welding tongs according to claim 1, characterized in that The laser emitter is a quasi - continuous fiber laser.

6. A welding process, characterized in that, The process uses the spot - welding tong electrode head as described in claim 3 and includes the following steps: Startup step: After placing the welding point of the plate to be welded between the two arms of the welding tong, turn on the spot - welding tong electrode head. Pre - pressing step: Turn on the driving cylinder (09), and the piston (10) moves and drives the pressing mechanism on the lower arm or the upper arm of the welding tong to move towards the pressing mechanism of the other arm until the plate is clamped. Heating step: After the laser emitter is turned on, adjust the laser beam parameters of the two laser emitters respectively. Pressurizing step: The driving motor and the transmission motor drive the static pressure heads to move towards each other. Cooling step: After turning off the laser emitter, make the static pressure heads move away from each other, and maintain the pressure of the driving cylinder to reduce the temperature of the welding point.

7. The welding process according to claim 6, characterized in that, In the pressurizing step, the static pressure heads located on the upper and lower sides of the plate continuously apply pressure.

8. The welding process according to claim 6, characterized in that, In the startup step, there is also a step of selecting an automatic mode or a manual mode. In the startup step, after the step of selecting the automatic mode, the main controller obtains the operation instructions and process parameters sent by the upper computer from the interaction interface; the process parameters include cylinder pressure parameters, static pressure head pressure parameters, and laser beam parameters. The laser beam parameters include the intensity, frequency, and working time of the laser beam.

9. The welding process according to claim 8, wherein, In the starting step, after selecting the manual mode step, the main controller obtains preset process parameters from the memory.

10. The welding process according to claim 8, characterized in that, Set the process parameters according to data including the thickness, metallurgical properties, mechanical properties, and laser reflection and refraction characteristics of the sheet material.

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