An automatic production line robot electrode cap changing system

Abstract

The application discloses an automatic production line robot electrode cap changing system, which comprises a PLC, a plurality of robots and a milling device, wherein the PLC is in bidirectional data connection with the plurality of robots and the milling device; the PLC records the welding times, the periodic welding point numbers and the standard milling times of each robot, controls the milling device to mill the electrode cap of the robot and records the milling times, obtains the electrode cap changing period of the robot according to the preset electrode cap changing standard and the periodic welding point numbers of the robot, divides the robot into a plurality of work groups according to the electrode cap changing period of the robot, divides the robot and / or the work groups into a plurality of line bodies according to the components of the production line, and controls the robot, the work group or the line body to change the electrode cap according to a preset strategy. The electrode cap changing under different conditions is realized through a plurality of segmented controls, the electrode cap changing under different conditions is effectively connected through PLC programming, and therefore the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the maintenance of robots on automated production lines, and particularly to a control system for replacing electrode caps on automated production line robots. Background Technology

[0002] The automotive manufacturing industry uses robotic welding guns extensively, which necessitates the replacement of a large number of electrode caps.

[0003] The robot can change electrode caps in the following ways:

[0004] 1. Manually disconnect the PLC from the robot, manually operate the robot to enter the maintenance position, and manually change the cap using a disassembly wrench. The PLC cannot control the cap changing process.

[0005] 2. The PLC and robot are connected normally. The manual operation panel is not considered. Factors such as electrode cap wear and welding count are not taken into account. Forced cap replacement is performed. Application scenarios include: equipment debugging process, quality certification process, other abnormal working range or special testing requirements.

[0006] 3. The PLC and robot are connected normally, and the robot is in full-automatic operation mode. When the electrode cap replacement conditions / lifespan are reached, the robot will automatically run the cap replacement program to replace the cap.

[0007] Currently, the replacement of robot electrode caps is based on the end-of-life signal of the weld joint after grinding, fed back from the welding controller. However, since the production line has a large number of robots, and each robot has a different number of welding joints, using only the end-of-life signal for weld joint grinding as the replacement signal leads to frequent downtime for each robot to replace electrode caps, reducing production efficiency. Furthermore, the replacement of multiple electrode caps within the same robot is not synchronized, resulting in wasted cycle time.

[0008] There is an urgent need for a more intelligent control system for electrode cap replacement to alleviate the waste of cycle time. Summary of the Invention

[0009] This invention provides an automated production line robot electrode cap changing system. It achieves electrode cap replacement under different conditions through multiple segmented control and uses PLC programming to effectively connect the electrode cap replacement under different conditions, thereby improving production efficiency.

[0010] The present invention discloses an automated production line robot electrode cap changing system, comprising: a PLC, multiple robots, and a milling device, wherein the PLC is bidirectionally connected to the multiple robots and the milling device; wherein,

[0011] The PLC records the number of welding operations, the number of weld points per cycle, and the number of standard milling operations for each robot.

[0012] The PLC compares the number of welding operations of the robot with the standard number of milling operations, then controls the milling device to mill the robot's electrode cap and records the number of milling operations.

[0013] The PLC determines the electrode cap replacement cycle of the robot based on the preset electrode cap replacement standard and the number of welding points in the robot's cycle.

[0014] The PLC divides the robot into multiple working groups based on the robot's electrode cap replacement cycle;

[0015] Based on the composition of the production line, the PLC divides the robots and / or work groups into multiple lines;

[0016] The PLC controls robots, work groups, or production lines to change electrode caps according to preset strategies.

[0017] Preferably, the electrode cap replacement standard is the number of milling operations, with each milling operation being approximately 0.05 mm, and the number of milling operations being 120.

[0018] Preferably, the standard for replacing the electrode cap is the lifeline length of the electrode cap, typically 6mm.

[0019] More preferably, the milling device is equipped with a length detection device for detecting the lifeline length of the electrode cap.

[0020] Preferably, the electrode cap replacement criteria are based on unexpected conditions, including: solder joint quality problems, solder joint patterns, or spots. Replacing the electrode cap under these conditions is not part of the normal operating procedure.

[0021] Preferably, the PLC also divides the robot into multiple working groups based on the electrical control safety circuit, load voltage, and the number of modules it carries. Each working group is an integrated control unit with independent logic operation capabilities.

[0022] Preferably, the preset strategy is to replace the electrode cap by working group or by line body.

[0023] Preferably, the preset strategy is to adjust the electrode cap replacement cycle and the standard number of milling operations of other robots according to the minimum electrode cap replacement cycle of each robot on the production line.

[0024] Preferably, the preset strategy is to take the minimum electrode cap replacement cycle of each robot on the line as the reference cycle, calculate the multiple relationship between the electrode cap replacement cycle of other robots and the reference cycle, and then adjust the electrode cap replacement cycle and the standard number of milling operations of other robots according to the multiple relationship.

[0025] Preferably, the preset strategy is to replace the electrode caps over time.

[0026] The automatic production line robot electrode cap changing system of the present invention uses a preset strategy as a central control network to monitor multiple production lines as a whole, and designs reasonable automatic cap changing trigger conditions, such as: controlling cap changing once a day based on production capacity; automatically counting and uniformly changing caps after reaching the life cycle based on logic algorithms; and uniformly changing caps by time and shift, thus avoiding wasted cap changing time. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the automatic production line robot electrode cap changing system of the present invention.

[0028] Figure 2 This is a schematic diagram of the grouping and production line of the automated production line robot electrode cap changing system of the present invention. Detailed Implementation

[0029] To clearly describe the present invention, it will now be described in further detail with reference to the accompanying drawings.

[0030] like Figure 1 , Figure 2 As shown, an automated production line robot electrode cap changing system is applied to vehicle manufacturing. It includes multiple robots (machines 11, 12...1n, 21, 22, 31...) that are bidirectionally connected to a PLC, and a milling device 2. The welding clamp of robot 21 is clamp number 21, and the welding clamp of robot 22 is clamp number 22. The PLC controls the milling device to mill the electrode caps of robots 21 and 22 and records the number of milling operations.

[0031] The PLC obtains the welding count and cycle welding point count for machine 21 and robot 22 respectively. The cycle welding point count for clamp 21 is 8, that is, 8 welding points need to be welded in one work cycle; the cycle welding point count for clamp 22 is 10, that is, 10 welding points need to be welded in one work cycle.

[0032] The space used in the electrode cap in this system is calculated as 6mm. Each milling consumes 0.05mm, and the number of milling times for the electrode cap is 6 / 0.05 = 120 times. The standard number of milling times is 120 solder joints for one milling of the electrode cap. Therefore, the PLC preset electrode cap replacement standard is 120 milling times, corresponding to 120*120 = 14400 solder joints.

[0033] To ensure consistent milling standards (each milling operation consumes 0.05mm, and the standard number of milling operations is 120 weld points per operation), the PLC, based on the preset electrode cap replacement standard (milling operations = 120 times, corresponding to 120 * 120 = 14400 weld points) and the 8 weld points per cycle for clamp No. 1, obtains that the electrode cap replacement cycle for robot No. 1 is 15.

[0034] Based on the preset electrode cap replacement standard (the standard number of milling operations is 120 weld points per milling operation, and the number of milling operations = 120 times, corresponding to 120 * 120 = 14400 weld points) and the number of weld points in cycle of clamp No. 22 is 10, the PLC obtains that the electrode cap replacement cycle of robot No. 22 is 12.

[0035] The PLC divides the robots into multiple workgroups based on their electrode cap replacement cycles. In this embodiment, robot number 21 has an electrode cap replacement cycle of 15 cycles and belongs to the first workgroup G1; robot number 22 has an electrode cap replacement cycle of 12 cycles and belongs to the second workgroup G2. If there are more robots, robots with the same replacement cycle can be grouped into the same workgroup.

[0036] Based on the components of the production line, the PLC divides the robots and / or work groups into multiple lines (A, N). In this embodiment, robot No. 21 and robot No. 22 are two robots working on the same production line and in adjacent steps during the vehicle body manufacturing process. If either robot stops to replace the electrode cap, it will affect the work of the other robot. Robots No. 21 and No. 22 belong to the first line A.

[0037] The PLC controls robots, work groups, or production lines to change electrode caps according to preset strategies.

[0038] In this embodiment, the preset strategy can be to replace the electrode cap by work group or by line body.

[0039] Replace by group: Replace the electrode caps of the first working group G1 every 15 cycles, and replace the electrode caps of the second working group G2 every 12 cycles; if the replacement is carried out by group based on the wear range of the electrode caps or based on the count, the milling cycle of the same group is consistent, and the electrode caps can be utilized to the maximum extent.

[0040] However, the electrode cap replacement cycle is inconsistent for robots on the same production line. For example, a line may have welding clamps numbered 11 to 1n, with the number of welding points increasing by one in each order. Replacing the electrode caps in groups would result in multiple work cycles for the entire line, severely impacting production efficiency.

[0041] When replacing the electrode caps on the same line: Since robots 21 and 22 belong to the preceding and following processes of line A, they process the same number of workpieces within the same replacement cycle. If the machine operates on a cycle of 120 weld points and 120 milling operations for the electrode caps, robot 22 on line A will be the first to reach the condition for electrode cap replacement after 12 cycles. At the same time, the electrode caps of all robots on line A must be replaced. The electrode cap of clamp 22 reaches its maximum service life, while the electrode cap of clamp 21 essentially wastes 2880 weld points. This method improves production efficiency, but robot 21 essentially wastes the last 24 milling operations.

[0042] Based on the above, a better solution is to adjust the electrode cap replacement cycle and standard number of milling operations of other robots according to the minimum electrode cap replacement cycle of each robot on the production line.

[0043] Let's take robots 21 and 22, which belong to the first line body, as examples.

[0044] The number of welding points per cycle for clamp No. 21 is 8, the replacement cycle is 15, the milling is 120 times, the actual number of welding points is 120*120=14400, and 14400 / 8=1800 workpieces can be produced.

[0045] The number of welding points per cycle for clamp #22 is 10, the replacement cycle is 12, the milling is performed 120 times, and the actual number of welding points is 120*120=14400. Therefore, 14400 / 10=1440 workpieces can be produced.

[0046] Based on the minimum electrode cap replacement cycle of 12 for robot A on the first production line, adjust the electrode cap replacement cycle of robot 21 to 12, and adjust the standard number of milling operations to 96.

[0047] After adjusting the electrode cap replacement cycle and the standard number of milling operations for robot 21, when robot 21 has completed 96 welding operations, the PLC controls the milling device 2 to mill the electrode cap of robot 21. The 2880 weld points between robots 21 and 22 are evenly distributed across 120 milling operations.

[0048] Although this method did not reuse the welding point limit of the electrode cap, it kept the electrode cap of robot No. 1 in optimal welding capacity at all times, improving welding quality, reducing the occurrence of welding point quality problems, welding point patterns or spots, etc., and improving production efficiency.

[0049] Based on the above, the optimal solution is to take the minimum electrode cap replacement cycle of each robot on the production line as the reference cycle, calculate the multiple relationship between the electrode cap replacement cycle of other robots and the reference cycle, and then adjust the electrode cap replacement cycle and the standard number of milling operations of other robots according to the multiple relationship.

[0050] Take robots numbered 11, 12, 13, and 14, which belong to the same line, as an example.

[0051] Robot No. 11 has 4 welding points per cycle, a replacement cycle of 30, 120 standard milling operations, and an actual number of welding points of 120 * 120 = 14400 points.

[0052] Robot No. 12 has 10 welding points per cycle, a replacement cycle of 12, 120 standard milling operations, and an actual number of welding points of 120 * 120 = 14400 points.

[0053] Robot No. 13 has 5 welding points per cycle, a replacement cycle of 24, 120 standard milling operations, and an actual number of welding points of 120 * 120 = 14400.

[0054] Robot No. 14 has 8 welding points per cycle, a replacement cycle of 15, 120 standard milling operations, and an actual number of welding points of 120 * 120 = 14400.

[0055] Robot No. 15 has 2 welding points per cycle, a replacement cycle of 60, 120 standard milling operations, and an actual number of welding points of 120 * 120 = 14400.

[0056] In the aforementioned production line, the electrode cap replacement cycle of robot No. 12 is the smallest, set at 12, which serves as the base cycle. The electrode cap replacement cycle of robot No. 11 (30) is 2.5 times that of robot No. 12 (12). Therefore, the ratio for robot No. 12 is 1, for robot No. 13 it is 2, for robot No. 14 it is 1.25, and for robot No. 15 it is 5. Since the electrode cap replacement cycle of robot No. 12 is the smallest, the ratio of the electrode cap replacement cycle of any robot on this production line to the base cycle is ≥1.

[0057] 1(2 0 )≤Multiple relationship<2(2) 1 When adjusting the electrode cap replacement cycle and standard number of milling operations of other robots according to the reference cycle;

[0058] Robot No. 12 has a multiplier of 1, a cycle number of welding points of 10, a replacement cycle of 12, and a standard milling cycle of 120 times.

[0059] The ratio of robot number 14 is 1.25, the number of weld points per cycle is 8, the replacement cycle is adjusted to 12, and the standard number of milling operations is adjusted to 96.

[0060] 2(2 1 )≤Multiple relationship<4(2) 2 When this happens, adjust the electrode cap replacement cycle and standard number of milling operations of other robots by double the base cycle.

[0061] Robot No. 11 has a multiplier of 2.5, a cycle number of welding points of 4, a replacement cycle of 24, and a standard milling operation of 96 times.

[0062] Robot No. 13 has a multiplier of 2, a cycle number of welding points of 5, a replacement cycle of 24, and a standard milling cycle of 120 times.

[0063] 2 n-1 ≤Multiple relationship<2 n At the same time, adjust the electrode cap replacement cycle and standard number of milling operations of other robots according to the reference cycle * n.

[0064] Robot No. 15 has a multiplier of 4, a cycle number of welding points of 2, a replacement cycle of 60, and a standard milling cycle of 120 times.

[0065] After adjusting according to the above strategy, when the number of welding operations of each robot reaches the adjusted standard number of milling operations, the PLC controls the milling device 2 to mill the electrode cap.

[0066] When the production line stopped for the first time, robots 12 and 14 milled 120 times, and only the electrode caps of robots 12 and 14 were replaced; robots 11 and 13 milled 60 times, and robot 15 milled 30 times.

[0067] When the production line stops for the second time, robots 12, 14, 11, and 13 will mill 120 times, and the electrode caps of robots 12, 14, 11, and 13 will be replaced; robot 15 will mill 60 times.

[0068] When the production line stopped for the third time, robots 12 and 14 milled 120 times, and only the electrode caps of robots 12 and 14 were replaced; robots 11 and 13 milled 60 times, and robot 15 milled 90 times.

[0069] When the production line stops for the fourth time, robots 12, 14, 11, 13, and 15 will mill 120 times, and the electrode caps of robots 12, 14, 11, 13, and 15 will be replaced.

[0070] This approach improves product quality, achieves a balance between the number of line stops and electrode cap waste, and also increases production efficiency.

[0071] In the aforementioned embodiments, the standard for replacing the electrode cap is the lifeline length of the electrode cap, which is generally 6mm. Based on common experience, the lifeline length can be calculated from the milling consumption of 0.05mm / time and the number of milling operations.

[0072] A length detection device can also be installed on the milling machine to detect the lifeline length of the electrode cap.

[0073] In addition to the aforementioned situations, electrode cap replacement can also be due to unforeseen circumstances, including: solder joint quality issues, solder joint patterns, or spots. Replacing the cap under these conditions is not part of the normal operating procedure.

[0074] The PLC also divides the robot into multiple working groups based on the electrical control safety circuit, load voltage, and the number of modules it carries. Each working group is an integrated control unit with independent logic operation capabilities.

[0075] The automatic production line robot electrode cap changing system of the present invention connects all robots in a single work group by dividing them into work groups, and allows one-click selection on the programming panel of the WINCC human-machine interface, enabling automatic cap changing for robots in a single work group.

[0076] Individual lines can be programmed independently, multiple workgroups can be organically combined to create a unified control interface for lines, enabling one-click cap replacement for a single line.

[0077] It can also be programmed to achieve intelligent calculation and automatic cap changing of the line body.

[0078] Based on this system, a central control network can be established to monitor multiple production lines in the section as a whole, and reasonable automatic cap-changing trigger conditions can be designed, such as:

[0079] 1. Based on the current designed production capacity, the daily output will be controlled within 1200 vehicles, and the cap will be changed once a day.

[0080] 2. Based on a logical algorithm, automatically count and replace the caps uniformly after the life cycle is reached.

[0081] 3. Develop panel controls and functions based on time units to achieve unified cap changing according to shifts under central control.

[0082] 4. Design automatic hat changing at specific times, such as automatically changing hats 30 minutes before the start of the workday each day, to avoid wasting time that staff would otherwise have to manually change hats.

[0083] This invention is a completely self-programmed implementation of segmented automatic cap changing function under various conditions. Furthermore, through the self-designed PLC master control program, it is interconnected with the robot program. This is a completely new invention and a new idea. Therefore, the overall intelligent automatic cap changing method and function, including the central control function, need to be protected.

[0084] This invention is entirely independently designed. Based on programming and mathematical theories, it achieves intelligent hat-changing functionality for robots, significantly reducing manpower and production costs, saving an average of over 60 minutes of production time per day. Furthermore, it features central control functionality for real-time data collection and monitoring of the site.

Claims

1. An automated production line robot electrode cap changing system, characterized in that, include: The system includes a PLC, multiple robots, and milling machines; the PLC is bidirectionally connected to each of the robots and milling machines. The PLC records the number of welding operations, the number of weld points per cycle, and the number of standard milling operations for each robot. The PLC compares the number of welding operations of the robot with the standard number of milling operations, then controls the milling device to mill the robot's electrode cap and records the number of milling operations. The milling device is equipped with a length detection device for detecting the lifeline length of the electrode cap; The PLC determines the electrode cap replacement cycle of the robot based on the preset electrode cap replacement standard and the number of welding points in the cycle of the robot; the electrode cap replacement standard is the number of milling operations and the lifespan of the electrode cap. The PLC divides the robot into multiple working groups based on the robot's electrode cap replacement cycle; Based on the components of the production line, the PLC divides robots and / or work groups into multiple lines. Robots working in adjacent steps, where stopping one robot to change an electrode cap would affect the work of another robot, also belong to the same line. The PLC controls robots, work groups, or production lines to replace electrode caps according to preset strategies. The preset strategy is to use the minimum electrode cap replacement cycle of each robot on the production line as the baseline cycle, calculate the multiple relationship between the electrode cap replacement cycle of other robots and the baseline cycle, and then adjust the electrode cap replacement cycle and the standard number of milling operations of other robots according to the multiple relationship: When 1 (2) 0 )≤Multiple relationship<2(2) 1 When this happens, adjust the electrode cap replacement cycle and standard number of milling operations of other robots according to the reference cycle; When 2 (2) 1 )≤Multiple relationship<4(2) 2 When this happens, adjust the electrode cap replacement cycle and standard number of milling operations of other robots by double the base cycle. When 2 n-1 ≤Multiple relationship<2 n At the same time, adjust the electrode cap replacement cycle and standard number of milling operations of other robots according to the reference cycle * n.

2. The automated production line robot electrode cap changing system as described in claim 1, characterized in that, The electrode cap is milled 0.05 mm each time, and the number of milling cycles is 120.

3. The automated production line robot electrode cap changing system as described in claim 1, characterized in that, The lifeline length of the electrode cap is 6mm.

4. The automated production line robot electrode cap changing system as described in claim 1, characterized in that, The electrode cap replacement standard is based on the occurrence of solder joint quality problems. Replacement is not a normal operating procedure.

5. The automated production line robot electrode cap changing system as described in claim 4, characterized in that, The quality problem of the solder joints is the solder joint pattern or spots.

6. The automated production line robot electrode cap changing system as described in claim 1, characterized in that, The preset strategy is to replace the electrode cap by working group or by line body.

7. The automated production line robot electrode cap changing system as described in claim 1, characterized in that, The preset strategy is to replace the electrode caps according to time.

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