Laser-assisted FDS screw plate material connecting method and system thereof

Abstract

The application discloses a kind of laser-assisted FDS screw plate material connecting method and system, it is related to plate material connecting technical field, to solve the problems, such as great processing difficulty, low efficiency, poor connection quality etc. of traditional FDS screw connection. The connecting method comprises: the heterogeneous plate material is stacked according to preset order and is applied 800-1500N uniform clamping force by edge clamping device, ensure that interface has no gap;CCD visual positioning system with positioning accuracy ±0.03mm is used to calibrate connecting point;According to processing space, plate thickness and material, select same side or opposite side distributed laser, adopt laser heat conduction heating (200W-400W, 3-5s) or laser melting heating (1300W-1700W, 5-7s), and temperature is monitored in real time by infrared thermal imager;After laser heating, FDS drive unit operates according to gradient pressure strategy, combined with laser sensor module to monitor connection depth, retreat to original position after reaching preset depth. The system comprises FDS drive unit, FDS screw, laser, plate material to be connected and workbench from top to bottom. The application expands plate material connection types and application scenarios, plate type coverage range expands 60%, application scenarios expand more than 50% than traditional equipment, shorten processing time, improve connection quality and production efficiency, reduce cost, suitable for new energy automobile body-in-white and other heterogeneous plate material connection scenarios.

Description

Technical Field

[0001] 0001 This invention relates to the field of sheet metal joining technology, and in particular to a laser-assisted FDS screw sheet metal joining method and system. Background Technology

[0002] 0002 In recent years, with the rise of new energy vehicles, "lightweighting" has become a development trend. High-strength steel, aluminum and magnesium alloy materials are widely used in body-in-white. For the connection of dissimilar materials, FDS screws (also known as flow drill screws or hot melt self-tapping screws) can replace traditional welding to achieve better connection results.

[0003] 0003 In related technologies, FDS screws offer numerous advantages for joining dissimilar materials, but also have some drawbacks. High-strength steel has high hardness and toughness, making direct machining of sheet metal connections with traditional FDS screws difficult. Furthermore, traditional FDS screw sheet metal connections require extremely high rotational torque and axial pressure, resulting in slow screw feed speeds and single-hole forming times as long as 10-15 seconds, making it difficult to meet batch processing needs. During machining, the plastic deformation of the sheet metal under the action of the FDS screw is uneven, easily leading to problems such as hole wall tearing, excessive burrs, and out-of-tolerance hole diameter (above ±0.3mm). Excessive axial pressure also results in excessive cutting force, causing residual stress on the hole wall, which may lead to stress corrosion cracking during subsequent use. Summary of the Invention

[0004] 0004 In view of the above-mentioned shortcomings of the prior art, the present invention provides a laser-assisted FDS screw plate connection method and system, which uses laser to heat the plate through laser heat conduction or laser melting to assist the connection of FDS screws between plates, thereby speeding up the connection and obtaining a high-quality connection.

[0005] 0005 The embodiments of the present invention are implemented through the following technical solutions:

[0006] 0006 In a first aspect, embodiments of the present invention provide a laser-assisted FDS screw plate connection method, the connection method comprising:

[0007] 0007 Step 1): Stack the dissimilar boards to be connected on the workbench in a preset order;

[0008] 0008 Step 2): The connection point is calibrated using the CCD vision positioning system and the edge clamping device is activated to apply a uniform clamping force to ensure that there are no gaps at the interface of the board.

[0009] 0009 Step 3): Select the laser arrangement method according to the processing space and the thickness of the plate. The laser distribution method can be distributed on the same side or on opposite sides. Select the laser heating method according to the material of the plate. The laser heating methods can be laser heat conduction heating and laser melting heating. At the same time, an infrared thermal imager is used to observe the temperature distribution of the laser heating area in real time.

[0010] 0010 Step 4): After laser heating is completed, the FDS drive unit operates according to the gradient pressure strategy;

[0011] 0011 Step 5): The laser sensor module monitors the connection depth of the FDS screw. When the preset connection depth is reached, the system controls the FDS drive unit to return to its original position, and the FDS screw completes the connection work.

[0012] The determination of ensuring a gapless interface at the board surface, as described in 0012, is made by using any one of the following operations or a combination thereof:

[0013] 0013 a) A 0.02mm feeler gauge cannot be inserted between the boards;

[0014] 0014 b) Determine whether there are gaps based on experience;

[0015] 0015 Preferably, the dissimilar sheet materials include metal sheets and non-metal sheets.

[0016] 0016 Preferably, the positioning accuracy of the CCD vision positioning system is ±0.03mm.

[0017] 0017 Preferably, the edge clamping device applies a uniformly distributed clamping force of 800-1500N.

[0018] 0018 Preferably, the laser is mounted on the side of the FDS drive unit via a ball screw linear guide and a turntable. The angle between the laser and the substrate is adjusted by the turntable to ensure that the laser penetration depth covers the interface area.

[0019] 0019 Preferably, the laser heating method includes the following aspects: the laser heat conduction heating method has a power of 200W-400W and a heating time of 3-5s, and uses laser negative defocus to heat the plate, which is suitable for connecting metal plates with low hardness or connecting metal plates and non-metal plates; the laser melting heating method has a power of 1300W-1700W and a heating time of 5-7s, and uses laser defocus to heat the plate, which is suitable for connecting metal plates with high hardness or multi-layer metal plates.

[0020] 0020 Preferably, the infrared thermal imager has a temperature measurement range of -20 to 1500℃ and a temperature measurement accuracy of ±2℃.

[0021] 0021 Preferably, the gradient pressure strategy includes the following stages

[0022] 0022 1) Initial stage: (-10mm - 2mm) Axial pressure is 800-1200N, FDS screw speed is 1000-2000r / min, feed 2mm to form positioning hole;

[0023] 0023 2) Intermediate stage: (2-total thickness) Axial pressure is 1500-2500N, FDS screw speed is 4000-6000r / min;

[0024] 0024 3) Final pressure stage; axial pressure is 2500-3000N, and pressure holding time is 0.5-2s.

[0025] 0025 Preferably, the laser sensor module achieves emergency stop of the FDS screw by transmitting a stop signal to the FDS drive device, with a response time of 10-100μm;

[0026] 0026 In a second aspect, embodiments of the present invention provide a laser-assisted FDS screw system, comprising, from top to bottom: an FDS drive unit, an FDS screw, a laser, a plate to be connected, and a worktable.

[0027] 0027 The plates to be connected shall be at least two layers, and when multiple layers of plates to be connected are used, they shall be stacked.

[0028] The laser described in 0028 has an adjustable laser aperture radius.

[0029] 0029 The beneficial effects of the connection scheme provided by the embodiments of the present invention include at least the following: Compared with the prior art, the connection method provided by the embodiments of the present invention can realize the connection of various sheet metals; the same-side / opposite-side arrangement of the laser can be switched as needed, adapting to the processing of narrow spaces and thick workpieces. In the scenario of connecting dissimilar sheet metals in the body-in-white of new energy vehicles, the applicable scenarios of the equipment are expanded by more than 50% compared with traditional FDS equipment; laser heat conduction heating is suitable for low-hardness metal materials, non-metal materials, and composite materials; laser melting heating is suitable for high-hardness metal materials and multi-layer sheet metal connections, expanding the range of sheet metal types covered by 60% compared with the prior art, and laser melting heating forms a new fusion between the sheet metals, increasing the connection area between the threads and the sheet metal, and improving the connection performance; at the same time, the gradient pressure strategy can reduce processing time, and the pressure holding stage can ensure a tight connection between the FDS screw and the sheet metal. Overall, the embodiments of the present invention expand the types of sheet metal connections, improve the applicable scenarios, reduce processing time, improve production efficiency, reduce costs, and improve connection performance. Attached Figure Description

[0030] 0030 In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] 0031 Figure 1 This is a schematic diagram of the connection of the FDS screw laser heat conduction heating plate.

[0032] 0032 Figure 2 This is a schematic diagram of the connection of FDS screw laser melting heating plate;

[0033] 0033 Figure 3 This is a schematic diagram showing how the pressure and rotation speed of the FDS drive device change with the thickness of the nailed plate.

[0034] 0034 Figure 4 This is a flowchart of the laser-assisted FDS screw plate connection method;

[0035] 0035 Figure 5 This is a schematic diagram of the connection in Example 1;

[0036] 0036 Figure 6 This is a schematic diagram of the connection in Example 2; Detailed Implementation

[0037] 0037 The plates to be connected used in this embodiment 1 include AA6061-T6 aluminum alloy plate with a thickness of 2.5mm and 22MnB5 high-strength steel plate with a thickness of 1.5mm.

[0038] 0038, for example Figure 2 As shown, this embodiment achieves the connection of dissimilar materials through the following five stages:

[0039] 0039 Step 1): Stack the dissimilar plates 103 and 104 to be connected on the workbench in a preset order;

[0040] 0040 Step 2): The connection point is calibrated using the CCD vision positioning system and the edge clamping device is activated to apply a uniform clamping force to ensure that there are no gaps at the interface of the board.

[0041] 0041 Step 3): Select the laser arrangement method according to the processing space and the thickness of the plate. The laser distribution method can be distributed on the same side or on opposite sides. Select the laser heating method according to the material of the plate. The laser heating methods can be laser heat conduction heating and laser melting heating. At the same time, an infrared thermal imager is used to observe the temperature distribution of the laser heating area in real time.

[0042] 0042 Step 4): After laser heating is completed, the FDS drive unit operates according to the gradient pressure strategy;

[0043] 0043 Step 5): The connection depth of FDS screw 101 is monitored by the laser sensor module. When the preset connection depth is reached, the system controls the FDS drive unit to return to its original position, and the FDS screw completes the connection work.

[0044] 0044 In this embodiment, the uniform clamping force is 2KN, the laser heating method is laser heat conduction heating, the initial gradient pressure is 800N, the screw speed is 1000r / min; the intermediate stage pressure is 1500N, the screw speed is 4000r / min; the final pressure stage pressure is 2500N, and the holding time is 0.5s.

[0045] 0045 The method for determining that there is no gap between the boards in this embodiment is that a 0.02mm feeler gauge cannot be inserted between the boards.

[0046] 0046 As shown in the figure, the connection joint formed in this embodiment uses laser heat conduction heating to precisely control the temperature of the area to be connected in the plate within the softening temperature range of 22MnB5 high-strength steel, which significantly reduces the feed resistance of the FDS screw without changing the core performance of the plate matrix.

[0047] 0047 The plates to be connected used in this embodiment 2 include AA6061-T6 aluminum alloy plate with a thickness of 2.5mm and 22MnB5 high-strength steel plate with a thickness of 1.5mm.

[0048] 0048, for example Figure 2 As shown, this embodiment achieves the connection of dissimilar materials through the following five stages:

[0049] 0049 Step 1): Stack the dissimilar plates 103 and 104 to be connected on the workbench in a preset order;

[0050] 0050 Step 2): The connection point is calibrated using the CCD vision positioning system and the edge clamping device is activated to apply a uniform clamping force to ensure that there are no gaps at the interface of the board.

[0051] 0051 Step 3): Select the laser arrangement method according to the processing space and the thickness of the sheet material. The laser distribution method can be distributed on the same side or opposite sides. Select the laser heating method according to the material of the sheet material. The laser heating methods can be laser heat conduction heating and laser melting heating. At the same time, an infrared thermal imager is used to observe the temperature distribution of the laser heating area in real time.

[0052] 0052 Step 4): After laser heating is completed, the FDS drive unit operates according to the gradient pressure strategy;

[0053] 0053 Step 5): The connection depth of FDS screw 101 is monitored by the laser sensor module. When the preset connection depth is reached, the system controls the FDS drive unit to return to its original position, and the FDS screw completes the connection work.

[0054] 0054 In this embodiment, the uniformly distributed clamping force is 2KN, the laser heating method is laser melting heating, the initial gradient pressure is 800N, the screw speed is 1200r / min; the intermediate stage pressure is 2000N, the screw speed is 6000r / min; the final pressure stage pressure is 2500N, and the holding time is 2s.

[0055] 0055 The method for determining that there is no gap between the boards in this embodiment is that a 0.02mm feeler gauge cannot be inserted between the boards.

[0056] 0056 As shown in the figure, the connection joint formed in this embodiment achieves partial melting of the 22MnB5 high-strength steel to be connected area through laser melting heating, and the AA6061-T6 aluminum alloy interface simultaneously reaches the melting state. A stable metallurgical bonding layer is formed at the interface of the plates, and the effective meshing area between the thread profile and the plate substrate is increased by more than 20% compared with the heat conduction heating process.

Claims

1. A laser-assisted FDS screw plate connection method and system, characterized in that... By using lasers to pre-treat the boards before joining them, it is possible to connect various types of boards and obtain high-quality joints.

2. The laser-assisted FDS board connection method according to claim 1, characterized in that, include: Step 1): Stack the dissimilar boards to be connected on the workbench in a preset order; Step 2): The connection point is calibrated using a CCD vision positioning system and the edge clamping device is activated to apply a uniform clamping force to ensure that there are no gaps at the interface of the board. Step 3): Select the laser arrangement method according to the processing space and the thickness of the sheet material. The laser distribution method can be distributed on the same side or opposite sides. Select the laser heating method according to the material of the sheet material. The laser heating methods can be laser heat conduction heating and laser melting heating. At the same time, an infrared thermal imager is used to observe the temperature distribution of the laser heating area in real time. Step 4): After laser heating is completed, the FDS drive unit operates according to the gradient pressure strategy; Step 5): The laser sensor module monitors the connection depth of the FDS screw. When the preset connection depth is reached, the system controls the FDS drive unit to return to its original position, and the FDS screw completes the connection work.

3. The method according to claim 1, characterized in that, The determination of ensuring that there are no gaps at the interface of the board material is made by using any one of the following operations or a combination thereof: a) A 0.02mm feeler gauge cannot be inserted between the boards; b) Determine if there are gaps based on experience.

4. The laser-assisted FDS board joining method according to claim 1, characterized in that, The aforementioned dissimilar sheet materials include metal sheet materials and non-metal sheet materials.

5. The laser-assisted FDS board joining method according to claim 1, characterized in that, The edge clamping device applies a uniform clamping force of 800-1500N.

6. The laser-assisted FDS board joining method according to claim 1, characterized in that, The laser is mounted on the side of the FDS drive unit via a ball screw, linear guide, and turntable. The angle between the laser and the substrate is adjusted by the turntable to ensure that the laser penetration depth covers the interface area.

7. The laser-assisted FDS board joining method according to claim 1, characterized in that, The laser heating methods include the following: laser heat conduction heating with a power of 200W-400W and a heating time of 3-5s, using laser negative defocusing to heat the sheet material, suitable for connecting metal plates with low hardness or connecting metal plates and non-metal plates; laser melting heating with a power of 1300W-1700W and a heating time of 5-7s, using laser defocusing to heat the sheet material, suitable for connecting metal plates with high hardness or multi-layer metal plates.

8. The laser-assisted FDS board joining method according to claim 1, characterized in that, The gradient pressure strategy includes the following stages: 1) Initial stage: (-10mm - 2mm) Axial pressure is 800-1200N, FDS screw speed is 1000-2000r / min, feed 2mm to form positioning hole; 2) Intermediate stage: (2-total thickness) Axial pressure is 1500-2500N, and FDS screw speed is 4000-6000r / min; 3) Final pressure stage; axial pressure of 2500-3000N, holding time of 0.5-2s.

9. The laser-assisted FDS board bonding system according to claim 1, characterized in that, From top to bottom, including: FDS drive unit, FDS screws, laser, plate to be connected, worktable.

10. The laser-assisted FDS sheet metal bonding system according to claim 1, characterized in that, The plates to be connected shall be at least two layers, and when multiple layers of plates are used, they shall be stacked.

Images