A flexible welding production line and a method for switching between fixture welding and maintenance stations

Abstract

The present invention discloses a flexible welding production line and a method for switching between fixture welding and maintenance stations, which is characterized by comprising a three-dimensional multi-layer main steel structure, wherein the first layer of the main steel structure is provided with a plurality of automated welding units and tooling maintenance units, the upper layer of the main structure is provided with a plurality of tooling storage units and equipment maintenance channels, a stacking robot is provided on one side of the main steel structure, and a plurality of fixtures are also included, each of which is equipped with an RFID radio frequency tag system, and each of which has the same base, and a central control system is also included, wherein the central control system drives the stacking robot to store and retrieve the fixtures. The production line and method of the present invention can save space and realize production switching of multiple models.

Description

Technical Field

[0001] The invention relates to a flexible welding production line, in particular to a clamp switching method of the flexible welding production line. Background Art

[0002] Flexible manufacturing technology is a novel concept model and new development trend for realizing future factories, and is a strategic move that determines the future development prospects of manufacturing enterprises. Flexible welding production lines can greatly save space and public equipment, integrate intelligent machinery and people, and flexibly coordinate from accepting orders to production.

[0003] Traditional motorcycle production lines all use manual labor to switch welding fixtures. There are three major problems: 1. The storage of welding fixtures requires a large amount of production space; 2. A large number of welding fixtures need to be managed manually, which can easily cause storage confusion when there are many models on the same line; 3. A large amount of manpower time is required to switch the production model. Summary of the invention

[0004] The first object of the present invention is to provide a flexible welding production line which saves space and can switch between vehicle types.

[0005] In order to achieve the above-mentioned purpose, the present invention is configured as follows: a flexible welding production line, characterized in that it includes a three-dimensional multi-layer main steel structure, the first layer of the main steel structure is provided with a plurality of automated welding units and tooling maintenance units, the upper layer of the main structure is provided with a plurality of tooling storage units and equipment maintenance channels, a stacking robot is provided on one side of the main steel structure, and also includes a plurality of fixtures, each of which is equipped with an RFID radio frequency tag system, and each of which has the same base, and also includes a central control system, and the central control system drives the stacking robot to access the fixtures. By adopting the above-mentioned method, the welding production of components of different vehicle models can be realized by switching the fixtures by the stacking robot, and the production space is saved by the three-dimensional storage and welding mode.

[0006] In order to further save space, a row of multiple automated welding units is provided on the first layer of the main steel structure, and a tooling maintenance unit is also provided on one side end of the first layer of the main steel structure.

[0007] In order to further save space, a row of multiple tooling storage units is respectively provided on the second floor and each floor above the main steel structure.

[0008] Preferably, each automated welding unit is equipped with a welding system, which includes a dual robot welding system, a smoke exhaust system, a three-axis positioner, a robot controller, and a welding power supply. The dual robot welding system is installed upside down on the top plate, the three-axis positioner is installed on the floor, and the robot controller and the welding power supply are installed on the equipment maintenance channel.

[0009] In order to further save space, a centralized smoke exhaust system is arranged on the equipment maintenance passage, and the centralized smoke exhaust system includes a plurality of vertical smoke exhaust pipes and a horizontal smoke exhaust main pipe. The bottom outlet of each vertical smoke exhaust pipe is arranged on the smoke exhaust port of the bottom plate of the equipment maintenance passage and is matched with an automated welding unit respectively. The top outlet of each vertical smoke exhaust pipe is connected to the horizontal smoke exhaust main pipe, and one end of the horizontal smoke exhaust main pipe is closed and the other end is open.

[0010] To further realize the switching of clamps for different types of vehicles, the base of the clamp includes a fork plate with two parallel fork entrances on the left and right, and the bottom of the fork plate also has a positioning plate with an outer contour larger than the outer contour of the fork plate, and a clamp positioning groove is arranged on one side of the positioning plate.

[0011] In order to further realize the positioning of different fixtures, the three-axis positioner includes a welding platform and a fixture positioning self-locking mechanism A, the fixture positioning self-locking mechanism A includes a push pin A fixedly arranged on the welding platform and matched with the fixture positioning groove, and also includes a vertical clamping mechanism A and a horizontal clamping mechanism A. The push pin A, the vertical clamping mechanism A and the horizontal clamping mechanism A are respectively arranged on three sides of the welding platform. The vertical clamping mechanism A includes a vertical cylinder A and a slide seat A located under the welding platform. The slide seat A is provided with a slide groove A, and a vertical clamping shaft A is slidably arranged on the slide groove A. A sliding shaft A passing through the slide groove is arranged on the vertical clamping shaft A, the lower end of the vertical clamping shaft A is connected to the vertical cylinder A, the upper end extends out of the welding platform, and a clamping block A is arranged on the top of the vertical clamping shaft A; the horizontal clamping mechanism A includes a transverse cylinder A, a support A and a transverse U-shaped pressure plate A, the lower cross arm A of the U-shaped pressure plate A is hinged to the support A, the lower cross arm A of the U-shaped pressure plate A is hinged to the connecting rod mechanism A, the connecting rod mechanism A is hinged to the transverse cylinder A, the upper cross arm A of the U-shaped pressure plate A is located on the welding platform and a clamping block A is arranged at the end of the upper cross arm A.

[0012] In order to further realize the positioning of different fixtures, the tooling maintenance unit includes an inspection platform and a fixture positioning self-locking mechanism B, the fixture positioning self-locking mechanism B includes a push pin B fixedly arranged on the inspection platform and matched with the fixture positioning groove, and also includes a vertical clamping mechanism B and a horizontal clamping mechanism B. The push pin B, the vertical clamping mechanism B and the horizontal clamping mechanism B are respectively arranged on three sides of the welding platform. The vertical clamping mechanism B includes a vertical cylinder B and a slide seat B located under the inspection platform. The slide seat B is provided with a slide groove B, and a vertical clamping shaft B is slidably arranged on the slide groove B. A sliding shaft B passing through the slide groove is arranged on the vertical clamping shaft B, the lower end of the vertical clamping shaft B is connected to the vertical cylinder B, the upper end extends out of the maintenance platform, and a clamping block B is arranged on the top of the vertical clamping shaft B; the horizontal clamping mechanism B includes a transverse cylinder B, a support B and a transverse U-shaped pressure plate B, the lower cross arm B of the U-shaped pressure plate B is hinged to the support B, the lower cross arm B of the U-shaped pressure plate B is hinged to the connecting rod mechanism B, the connecting rod mechanism B is hinged to the transverse cylinder B, the upper cross arm B of the U-shaped pressure plate B is located on the maintenance platform and a clamping block B is arranged at the end of the upper cross arm B.

[0013] The second object of the present invention is to provide a method for switching the fixture welding stations of a flexible welding production line, and adopt the above-mentioned flexible welding production line to switch according to the following steps:

[0014] (1) Input the production switching command on the touch screen of the central control system;

[0015] (2) The program self-checks to confirm whether the switching conditions are met (i.e., all sensors meet the production switching conditions. If not, relevant warnings must be lifted according to the prompts). If the switching conditions are met, the production line begins to flexibly switch production models;

[0016] (3) All welding fixtures are unlocked from the three-axis positioner;

[0017] (4) The stacking robot moves to the first station and forks out the fixture, while reading the RFID information on the fixture;

[0018] (5) After identifying the fixture through RFID, the stacking robot transports the fixture back to the fixture warehouse;

[0019] (6) According to the issued product production switching instruction, the stacker moves to the position of the relevant product fixture, reads the fixture RFID to identify the fixture, and after confirming the fixture identity, the stacker forks out the new product fixture and moves it to the first workstation and then separates it from the fixture. The fixture positioning self-locking mechanism of the fixture and the three-axis positioner is activated, and the locking signal is sent to the central control system at the same time;

[0020] (7) The three-axis positioner at the first station is started, and the fixture on the other side of the three-axis positioner enters the switching position;

[0021] (8) Repeat steps (4) to (6) to complete the first station fixture switching;

[0022] (9) After the central control system obtains the locking signal of the two clamps at the first workstation, it switches the clamps at the next workstation until all the clamps at all workstations are switched.

[0023] The third object of the present invention is to provide a method for switching the fixture maintenance station of a flexible welding production line, and adopt the above-mentioned flexible welding production line to switch according to the following steps:

[0024] (1) Enter the maintenance instruction on the touch screen of the central control system and select the fixture to be repaired on the screen;

[0025] (2) The central control system obtains the actual location of the fixture to be repaired from the warehouse database. If the fixture is located on a three-axis positioner, the self-locking mechanism on the three-axis positioner is opened, and the stacking robot moves to the three-axis positioner to pick up the fixture; if the fixture is located in the warehouse, the stacking robot directly moves to the corresponding fixture position in the warehouse to pick up the fixture;

[0026] (3) The stacking robot forks out the fixture to be repaired and moves to the maintenance station, where it is separated from the fixture and a maintenance signal is sent to the central control system.

[0027] (4) The fixture positioning self-locking mechanism of the fixture and tooling maintenance unit is activated, and the locking signal is sent to the central control system at the same time, and the workers carry out equipment maintenance and inspection operations;

[0028] (5) The stacking robot moves to the maintenance station and forks out the fixture, while reading the RFID information on the fixture;

[0029] (6) After the identity of the fixture is identified through RFID, if the fixture is a model not in production, the stacking robot will transport the fixture back to the fixture warehouse; if the fixture is a model in production, the stacking robot will transport the fixture to the relevant production station.

[0030] Beneficial effects:

[0031] The flexible welding production line of the present invention has the following advantages: 1. In terms of overall layout, it creates a unique three-dimensional layout of upper-level fixture storage and lower-level automated welding; the two systems share the same site, making full use of the site's height space resources, and solving the problem of realizing flexible co-production of multiple vehicle models on a smaller site.

[0032] 2. A multi-layer fixture storage system is designed, which can store a large number of welding fixtures in an orderly manner, truly realizing the function of the fixture library and solving the problem of chaotic fixture management in the actual co-production of multiple models.

[0033] 3. Each fixture is equipped with an RFID radio frequency tag system, which cooperates with a dedicated warehouse management system and stacking robot to efficiently switch fixtures and manage production, realizing one-click automatic switching of production models.

[0034] 4. Through the same special fixture base, all fixtures are compatible with the fork picking of the stacking robot; the welding fixture is sent to the welding station by the warehouse system stacker robot, and the dedicated positioning mechanism on the welding station realizes the precise positioning and installation of the welding fixture and the three-axis positioner, solving the problem of insufficient fixture repetition accuracy that is easy to occur in flexible automatic production.

[0035] 5. A special maintenance unit is designed, which has special maintenance tooling for positioning welding fixtures. The welding fixture can be transferred to the three-coordinate detection area for detection through this unit.

[0036] 6. An independent equipment maintenance channel is designed to facilitate equipment maintenance.

[0037] 7. The design has a centralized smoke exhaust system, and the production line has centralized smoke exhaust and dust removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the front axonometric view of the flexible welding production line;

[0039] Figure 2 This is the rear axonometric view of the flexible welding production line;

[0040] Figure 3 This is the axonometric view of the back of the main steel structure;

[0041] Figure 4 This is the front axonometric view of the main steel structure;

[0042] Figure 5 This is the back view of the flexible welding production line;

[0043] Figure 6 This is the axonometric drawing of the three-axis positioner;

[0044] Figure 7 This is the axonometric drawing of the tooling maintenance unit;

[0045] Figure 8 Axonometric measurement of self-locking mechanisms for fixture and clamp positioning Figure 1 ;

[0046] Fig. 9 A top view of the clamp and the clamp positioning self-locking mechanism;

[0047] Fig.10 Axonometric measurement of self-locking mechanisms for fixture and clamp positioning Figure 2 ;

[0048] Fig.11and the structural diagram of the horizontal clamping mechanism;

[0049] Fig.12 This is the structural diagram of the vertical clamping mechanism.

[0050] Explanation of reference numbers: main steel structure 1, automated welding unit 2, tooling storage unit 3, equipment maintenance channel 4, tooling maintenance unit 5, stacking robot 6, fixture 7, dual robot welding system 8, three-axis positioner 9, robot controller 10, welding power supply 11, vertical smoke exhaust pipe 12, horizontal smoke exhaust main pipe 13, fork plate 14, positioning plate 15, fixture positioning V-groove 16, welding platform 17, maintenance platform 18, sales promotion unit B19, vertical cylinder B20, slide B21, support 22, slide B23, vertical clamping shaft B24, sliding shaft B25, clamping block B26, horizontal cylinder B27, support B28, U-shaped pressure plate B29, connecting rod B30, connecting rod C31, ladder 32, guardrail 33, pressure block B34. DETAILED DESCRIPTION

[0051] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings, but the present invention is not limited to these implementation modes, and any improvement or substitution based on the basic spirit of the present embodiment still falls within the scope of protection required by the claims of the present invention.

[0052] Example: Figure 1-12 As shown, a flexible welding production line includes a three-dimensional multi-layer main steel structure, wherein the main steel structure 1 is a steel structure building assembled by connecting steel sections and steel pipes by screw connection or welding. The bottom layer is planned with a flexible automated welding unit and a tool maintenance unit, and the upper layer is planned with a tool automatic storage system, a centralized smoke exhaust system, and an equipment maintenance channel.

[0053] Specifically, the first layer of the main steel structure is provided with a plurality of automated welding units 2 and tooling maintenance units 5. The upper layer of the main structure is provided with a plurality of tooling storage units 3 and equipment maintenance passages 4. A ladder 32 is provided at one end of the maintenance equipment passage for easy access, and guardrails are provided on the edges of the maintenance passage and the ladder to ensure safety. A stacking robot 6 is provided on one side of the main steel structure, and also includes a plurality of clamps 7, each of which is equipped with an RFID radio frequency tag system, and each of which has the same base, and also includes a central control system, which drives the stacking robot to store and retrieve the clamps. The stacking robot is arranged on the front side of the main steel structure, the maintenance equipment passage is arranged on the rear side of the main steel structure, and the ladder is arranged on the left side of the main steel structure.

[0054] In this embodiment, the first layer of the main steel structure is provided with a row of multiple automated welding units, and a tool maintenance unit is also provided at one side end of the first layer of the main steel structure. The second layer and each layer above the main steel structure are respectively provided with a row of multiple tool storage units. The main steel structure in this embodiment has four layers in total, therefore, the first layer is provided with an automated welding unit, the second layer, the third layer, and the fourth layer are all provided with tool storage units, and the maintenance passage is provided on the second layer.

[0055] In this embodiment, each automated welding unit is equipped with a welding system, which includes a dual robot welding system 8, a smoke exhaust system, a three-axis positioner 9, a robot controller 10, and a welding power supply 11. The dual robot welding system is installed upside down on the top plate, the three-axis positioner is installed on the floor, and the robot controller and the welding power supply are installed on the equipment maintenance channel.

[0056] As another implementation of this embodiment, a centralized smoke exhaust system is arranged on the equipment maintenance passage, and the centralized smoke exhaust system includes a plurality of vertical smoke exhaust pipes 12 and a horizontal smoke exhaust main pipe 13. The bottom outlet of each vertical smoke exhaust pipe is arranged on the smoke exhaust port of the bottom plate of the equipment maintenance passage and is matched with an automated welding unit respectively. The top outlet of each vertical smoke exhaust pipe is connected to the horizontal smoke exhaust main pipe, and one end of the horizontal smoke exhaust main pipe is closed and the other end is open.

[0057] In this embodiment, the base of the clamp includes a fork plate 14 with two parallel fork entrances on the left and right. The bottom of the fork plate also has a positioning plate 15 whose outer contour is larger than the outer contour of the fork plate. A clamp positioning V-shaped groove 16 and a rectangular groove passing through the side are provided on one side of the positioning plate.

[0058] The three-axis positioner includes a welding platform 17 and a clamp positioning self-locking mechanism A. The clamp positioning self-locking mechanism A includes a push pin A fixedly arranged on the welding platform and cooperating with the clamp positioning V-groove and rectangular groove. It also includes a vertical clamping mechanism A and a horizontal clamping mechanism A. The push pin A, the vertical clamping mechanism A and the horizontal clamping mechanism A are arranged on three sides of the welding platform for positioning the positioning plate of the clamp from three sides. The vertical clamping mechanism A includes a vertical cylinder A and a slide A located under the welding platform, the slide A is provided with a slide groove A, a vertical clamping shaft A is slidably provided in the slide groove A, and a sliding shaft A passing through the slide groove is provided on the vertical clamping shaft, the lower end of the vertical clamping shaft A is connected to the vertical cylinder A, the upper end extends out of the welding platform, and a clamping block A is provided on the top of the vertical clamping shaft A; the horizontal clamping mechanism A includes a transverse cylinder A, a support A and a transverse U-shaped pressure plate A, the lower cross arm A of the U-shaped pressure plate A is hinged to the support A, the lower cross arm A of the U-shaped pressure plate A is hinged to the connecting rod A, the connecting rod A is hinged to the transverse cylinder A, the upper cross arm A of the U-shaped pressure plate A is located on the welding platform and a clamping block A is provided at the end of the upper cross arm A.

[0059] As another implementation in this embodiment, the tooling maintenance unit includes an inspection platform 18 and a fixture positioning self-locking mechanism B, the fixture positioning self-locking mechanism B includes a push pin B19 fixedly arranged on the inspection platform and matched with the fixture positioning V-groove and rectangular groove, and also includes a vertical clamping mechanism B and a horizontal clamping mechanism B. The push pin A, vertical clamping mechanism A and horizontal clamping mechanism A are respectively arranged on three sides of the welding platform, and are used to position the positioning plate of the fixture from three sides. The vertical clamping mechanism B includes a vertical cylinder B20 and a slide B21 located under the inspection platform, the vertical cylinder B is fixed on the support 22, the slide B is fixed on the support, and the slide is fixedly connected to the bottom surface of the inspection platform. The slide B is provided with a slide groove B23, a vertical clamping shaft B24 is slidably arranged in the slide groove B, and a sliding shaft B25 passing through the slide groove is provided on the vertical clamping shaft. In this embodiment, the slide is vertically arranged, and the upper part of the slide has a curved section that is curved transversely, through which a small transverse movement of the vertical clamping shaft can be achieved, so as to adjust the clamping position. The lower end of the vertical clamping shaft B is connected to the vertical cylinder B, and the upper end extends out of the maintenance platform, and a clamping block B26 is arranged on the top of the vertical clamping shaft B; the horizontal clamping mechanism B includes a transverse cylinder B27, a support B28 and a transverse U-shaped pressure plate B29, the support B is fixedly connected to the bottom surface of the maintenance platform, the lower cross arm B of the U-shaped pressure plate B is hinged to the support B, the lower cross arm B of the U-shaped pressure plate B is hinged to one end of the connecting rod B30, and the other end of the connecting rod B is hinged to the transverse cylinder B through the connecting rod C31, the upper cross arm B of the U-shaped pressure plate B is located on the maintenance platform, and a clamping block B34 is arranged at the end of the upper cross arm B. The fixture positioning self-locking mechanism B of the tooling maintenance unit package in this embodiment is consistent with the fixture positioning self-locking mechanism A of the three-axis positioner. When positioning the fixture, the stacking robot first places the fixture positioning plate on the welding platform or maintenance platform and performs rough positioning by pushing the pin, and then performs fine positioning by the vertical clamping mechanism and the horizontal clamping mechanism after placement.

[0060] The flexible welding production line of this embodiment has the following characteristics: 1. In terms of overall layout, it has created a unique three-dimensional layout with upper-level fixture storage and lower-level automated welding; the two systems share the same site, making full use of the site's height space resources, and solving the problem of flexible co-production of multiple models on a smaller site. 2. A multi-layer fixture storage system is designed, which can store a large number of welding fixtures in an orderly manner, truly realizing the function of a fixture library, and solving the problem of chaotic fixture management in the actual co-production of multiple models. 3. Each fixture is equipped with an RFID radio frequency tag system, which cooperates with a dedicated warehouse management system and stacking robot to efficiently switch fixtures, efficiently manage production, and realize one-click automatic switching of production models. 4. Through the same special fixture base, all fixtures are compatible with the fork picking of the stacking robot; the welding fixture is sent to the welding station by the warehouse system stacker robot, and the dedicated positioning mechanism on the welding station realizes the precise positioning and installation of the welding fixture and the three-axis positioner, solving the problem of insufficient fixture repetition accuracy that is prone to occur in flexible automatic production. 5. A special maintenance unit is designed, which has special maintenance tools for positioning welding fixtures. The welding fixtures can be transferred to the three-coordinate inspection area for inspection through this unit. 6. An independent equipment maintenance channel is designed to facilitate equipment maintenance. 7. A centralized smoke exhaust system is designed to centrally exhaust smoke and remove dust on the production line.

[0061] In this embodiment, the stacking robot, the dual robot welding system, the three-axis positioner, the robot controller and the central control system are existing technologies and will not be described in detail here.

[0062] In addition, this embodiment also provides a method for switching the fixture welding stations of a flexible welding production line with two fixtures at the same station, and uses the above-mentioned flexible welding production line to switch according to the following steps:

[0063] (1) Input the production switching command on the touch screen of the central control system;

[0064] (2) The program self-checks to confirm whether the switching conditions are met (i.e., all sensors meet the production switching conditions. If not, relevant warnings must be lifted according to the prompts). If the switching conditions are met, the production line begins to flexibly switch production models;

[0065] (3) All welding fixtures are unlocked from the three-axis positioner;

[0066] (4) The stacking robot moves to the first station and forks out the fixture, while reading the RFID information on the fixture;

[0067] (5) After identifying the fixture through RFID, the stacking robot transports the fixture back to the fixture warehouse;

[0068] (6) According to the issued product production switching instruction, the stacker moves to the position of the relevant product fixture, reads the fixture RFID to identify the fixture, and after confirming the fixture identity, the stacker forks out the new product fixture and moves it to the first workstation and then separates it from the fixture. The fixture positioning self-locking mechanism of the fixture and the three-axis positioner is activated, and the locking signal is sent to the central control system at the same time;

[0069] (7) The three-axis positioner at the first station is started, and the fixture on the other side of the three-axis positioner enters the switching position;

[0070] (8) Repeat steps (4) to (6) to complete the first station fixture switching;

[0071] (9) After the central control system obtains the locking signal of the two clamps at the first workstation, it switches the clamps at the next workstation until all the clamps at all workstations are switched.

[0072] Among them, one or more fixtures can be set at the same workstation.

[0073] In addition, this embodiment also provides a method for switching the fixture maintenance station of a flexible welding production line, and uses the above-mentioned flexible welding production line to switch according to the following steps:

[0074] (1) Enter the maintenance instruction on the touch screen of the central control system and select the fixture to be repaired on the screen;

[0075] (2) The central control system obtains the actual location of the fixture to be repaired from the warehouse database. If the fixture is located on a three-axis positioner, the self-locking mechanism on the three-axis positioner is opened, and the stacking robot moves to the three-axis positioner to pick up the fixture; if the fixture is located in the warehouse, the stacking robot directly moves to the corresponding fixture position in the warehouse to pick up the fixture;

[0076] (3) The stacking robot forks out the fixture to be repaired and moves to the maintenance station, where it is separated from the fixture and a maintenance signal is sent to the central control system.

[0077] (4) The fixture positioning self-locking mechanism of the fixture and tooling maintenance unit is activated, and the locking signal is sent to the central control system at the same time, and the workers carry out equipment maintenance and inspection operations;

[0078] (5) The stacking robot moves to the maintenance station and forks out the fixture, while reading the RFID information on the fixture;

[0079] (6) After the identity of the fixture is identified through RFID, if the fixture is a model not in production, the stacking robot will transport the fixture back to the fixture warehouse; if the fixture is a model in production, the stacking robot will transport the fixture to the relevant production station.

[0080] The production conditions served by the production line of this embodiment are to realize the flexible co-production of 5 motorcycle products in a 300 square meter site. The structures of various motorcycle products are quite different. Each motorcycle product requires 10 sets of welding fixtures, and flexible automatic co-production and switching of 50 sets of welding fixtures need to be realized. This production line combines automated three-dimensional warehousing with flexible automated production technology. By combining the stacking robot with the three-dimensional warehouse, the problem of storing a large number of tooling fixtures in a small space is solved; through the same special fixture base, all fixtures are compatible with the fork picking of the stacking robot; through a special mechanism, a high repeat position accuracy is maintained after the fixture is switched; a special maintenance unit is designed, and there is a special maintenance tool for positioning the welding fixture in the maintenance unit. The welding fixture can be transferred to the three-coordinate detection area for detection through this unit; the automatic storage of the welding fixture is realized by assembling the RFID radio frequency tag system on each fixture, and the welding fixture that has been inspected or repaired can be automatically stored by RFID.

Claims

1. A flexible welding production line, characterized in that: It includes a three-dimensional multi-layer main steel structure, wherein the first layer of the main steel structure is provided with a plurality of automated welding units and tooling maintenance units, the upper layer of the main steel structure is provided with a fixture library and an equipment maintenance passage composed of a plurality of tooling storage units, a stacking robot is provided on one side of the main steel structure, the stacking robot is provided on the front side of the main steel structure, and the equipment maintenance passage is provided on the rear side of the main steel structure; It also includes a plurality of fixtures, each of which is equipped with an RFID radio frequency tag system, and each of which has the same base, and also includes a central control system, which drives the stacking robot to store and retrieve the fixtures; The first layer of the main steel structure is provided with a row of multiple automated welding units, and a tooling maintenance unit is also provided at one end of the first layer of the main steel structure; The second layer and each layer above the main steel structure are respectively provided with a row of multiple tooling storage units; Each automated welding unit is equipped with a welding system, which includes a dual-robot welding system, a fume exhaust system, a three-axis positioner, a robot controller, and a welding power source. The dual-robot welding system is mounted upside down on the top plate, the three-axis positioner is mounted on the floor, and the robot controller and the welding power source are mounted on the equipment maintenance channel; The equipment maintenance passage is provided with a centralized smoke exhaust system, which includes a plurality of vertical smoke exhaust pipes and a horizontal smoke exhaust main pipe. The bottom outlet of each vertical smoke exhaust pipe is provided on the smoke exhaust port of the bottom plate of the equipment maintenance passage and is matched with an automated welding unit respectively. The top outlet of each vertical smoke exhaust pipe is connected with the horizontal smoke exhaust main pipe, and one end of the horizontal smoke exhaust main pipe is closed and the other end is open. The base of the clamp comprises a fork plate with two parallel fork entrances on the left and right sides, and the bottom of the fork plate also comprises a positioning plate whose outer contour is larger than the outer contour of the fork plate, and a clamp positioning groove is arranged on one side of the positioning plate.

2. The flexible welding production line according to claim 1, characterized in that: The three-axis positioner includes a welding platform and a fixture positioning self-locking mechanism A, the fixture positioning self-locking mechanism A includes a push pin A fixedly arranged on the welding platform and matched with the fixture positioning groove, and also includes a vertical clamping mechanism A and a horizontal clamping mechanism A, the push pin A, the vertical clamping mechanism A and the horizontal clamping mechanism A are respectively arranged on three sides of the welding platform, the vertical clamping mechanism A includes a vertical cylinder A and a slide seat A located under the welding platform, the slide seat A is provided with a slide groove A, the slide groove A is slidably provided with a vertical clamping shaft A, and the vertical clamping shaft A is provided with a A sliding shaft A passing through the slide groove is provided, the lower end of the vertical clamping shaft A is connected to the vertical cylinder A, the upper end extends out of the welding platform, and a clamping block A is provided on the top of the vertical clamping shaft A; the horizontal clamping mechanism A includes a transverse cylinder A, a support A and a transverse U-shaped pressure plate A, the lower cross arm A of the U-shaped pressure plate A is hinged to the support A, the lower cross arm A of the U-shaped pressure plate A is hinged to the connecting rod mechanism A, the connecting rod mechanism A is hinged to the transverse cylinder A, the upper cross arm A of the U-shaped pressure plate A is located on the welding platform and a clamping block A is provided at the end of the upper cross arm A.

3. The flexible welding production line according to claim 1, characterized in that: The tooling maintenance unit includes an inspection platform and a fixture positioning self-locking mechanism B, the fixture positioning self-locking mechanism B includes a push pin B fixedly arranged on the inspection platform and matched with the fixture positioning groove, and also includes a vertical clamping mechanism B and a horizontal clamping mechanism B, the push pin B, the vertical clamping mechanism B and the horizontal clamping mechanism B are respectively arranged on three sides of the welding platform, the vertical clamping mechanism B includes a vertical cylinder B and a slide seat B located under the inspection platform, the slide seat B is provided with a slide slot B, the slide slot B is slidably provided with a vertical clamping shaft B, and the vertical clamping shaft B is provided with a A sliding shaft B passing through the slide groove is provided, the lower end of the vertical clamping shaft B is connected to the vertical cylinder B, the upper end extends out of the maintenance platform, and a clamping block B is provided on the top of the vertical clamping shaft B; the horizontal clamping mechanism B includes a transverse cylinder B, a support B and a transverse U-shaped pressure plate B, the lower cross arm B of the U-shaped pressure plate B is hinged to the support B, the lower cross arm B of the U-shaped pressure plate B is hinged to the connecting rod mechanism B, the connecting rod mechanism B is hinged to the transverse cylinder B, the upper cross arm B of the U-shaped pressure plate B is located on the maintenance platform and a clamping block B is provided at the end of the upper cross arm B.

4. A method for switching a fixture welding station of a flexible welding production line, using the flexible welding production line according to claim 2, characterized in that: Follow these steps to switch: (1) Input the production switching command on the touch screen of the central control system; (2) The program self-checks to confirm whether the switching conditions are met, that is, whether all sensors meet the production switching conditions. If not, relevant warnings need to be removed according to the prompts. When the switching conditions are met, the production line begins to flexibly switch production models; (3) All welding fixtures are unlocked from the three-axis positioner; (4) The stacking robot moves to the first station and forks out the fixture, while reading the RFID information on the fixture; (5) After identifying the fixture through RFID, the stacking robot transports the fixture back to the fixture warehouse; (6) According to the issued product production switching instruction, the stacking robot moves to the position of the relevant product fixture, reads the fixture RFID to identify the fixture, and after confirming the fixture identity, the stacking robot forks out the new product fixture and moves to the first workstation and then separates from the fixture. The fixture positioning self-locking mechanism A of the fixture and the three-axis positioner is activated, and the locking signal is sent to the central control system at the same time; (7) The three-axis positioner at the first station is started, and the fixture on the other side of the three-axis positioner enters the switching position; (8) Repeat steps (4) to (6) to complete the first station fixture switching; (9) After the central control system obtains the locking signal of the two clamps at the first workstation, it switches the clamps at the next workstation until all the clamps at all workstations are switched.

5. A method for switching fixture maintenance stations of a flexible welding production line, using the flexible welding production line according to claim 3, characterized in that: Follow these steps to switch: (1) Enter the maintenance instruction on the touch screen of the central control system and select the fixture to be repaired on the screen; (2) The central control system obtains the actual location of the fixture to be repaired from the warehouse database. If the fixture is located on a three-axis positioner, the self-locking mechanism on the three-axis positioner is opened, and the stacking robot goes to the three-axis positioner to pick up the fixture; if the fixture is located in the fixture library, the stacking robot goes directly to the corresponding fixture position in the fixture library to pick up the fixture; (3) The stacking robot forks out the fixture to be repaired and moves to the maintenance station, where it is separated from the fixture. At the same time, a maintenance signal is sent to the central control system. (4) The fixture positioning self-locking mechanism B of the fixture and tooling maintenance unit is activated, and the locking signal is sent to the central control system at the same time, and the worker performs equipment maintenance and inspection operations; (5) The stacking robot moves to the maintenance station and forks out the fixture, while reading the RFID information on the fixture; (6) After the identity of the fixture is identified through RFID, if the fixture is a model not in production, the stacking robot will transport the fixture back to the fixture warehouse; if the fixture is a model in production, the stacking robot will transport the fixture to the relevant production station.

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