Method, control device and system for grinding electrode tip of spot welding gun

Abstract

The invention relates to a method for grinding electrode tips of a spot welding gun, the spot welding gun comprising a movable electrode and a counter electrode paired with the movable electrode, the movable electrode and the counter electrode each comprising a detachably assembled electrode tip, the method comprising: ascertaining the current welding point number of the electrode tips; according to the current welding point number and the pre-determined early warning welding point number, whether grinding operation needs to be activated or not is determined; activating the grinding operation when it is ascertained that the grinding operation needs to be activated; after each grinding operation is completed, the actual grinding amount of the electrode tip is determined based on zero calibration of the electrode tip; the accumulated grinding amount of the electrode tip after multiple times of grinding operation is calculated by accumulating the actual grinding amount; and the accumulated grinding amount is compared with a grinding threshold value, and when the accumulated grinding amount exceeds or is equal to the grinding threshold value, electrode tip replacement operation is activated. The invention further relates to a control device and a system for grinding an electrode tip of a spot welding gun.

Description

Technical Field

[0001] The invention relates to the field of electrode tip grinding, and in general to a method, a control device and a system for grinding an electrode tip of a spot welding gun. Background Art

[0002] Spot welding refers to a welding method that uses a cylindrical electrode to form a weld spot between the contact surfaces of two overlapping workpieces. When performing the spot welding operation, the workpieces are first brought into close contact, and then the electrodes are energized. The contact between the workpieces melts under the action of resistance heat, and a weld spot is formed after cooling. As a method of implementing resistance welding, spot welding is mainly suitable for welding thin plate structures, stampings, and steel bars. For example, in the automobile manufacturing industry, spot welding is suitable for welding body structures.

[0003] However, with repeated use of the spot welding gun, the electrode tip of the spot welding gun may undergo unexpected deformation and wear under the action of heat and electricity, and may form an unexpected oxide film or gray phase layer, thereby reducing the current density of the electrode tip when using the spot welding gun, thereby reducing the welding quality.

[0004] Therefore, it is necessary to implement targeted grinding to the electrode tip of the spot welding gun so as to reconstruct the working end face configuration of the electrode tip. In addition, by grinding the electrode tip, the oxide film or the gray phase layer produced in the spot welding process can also be removed.

[0005] At present, the electrode tip is usually ground by special grinding equipment. However, in order to ensure good spot welding performance, the amount of electrode tip that can be ground is relatively limited, and thus the number of times the electrode tip can be ground is relatively limited. Once the grinding limit is reached, a new electrode tip needs to be replaced.

[0006] Therefore, it is desirable to provide an improved grinding method, control apparatus, and system for an electrode tip of a spot welding gun to allow advantageous improvements in electrode tip service life, grinding accuracy, and / or grinding management. Summary of the invention

[0007] The object of the present invention is to provide a method, a control device and a system for grinding an electrode tip of a spot welding gun that can overcome at least one of the drawbacks of the prior art.

[0008] According to a first aspect of the present invention, a method for grinding an electrode tip of a spot welding gun is proposed, wherein the spot welding gun comprises a movable electrode and a paired electrode paired with the movable electrode, wherein the movable electrode and the paired electrode respectively comprise electrode tips that can be detachably assembled, and wherein the method comprises: finding out the current number of welding points of the electrode tip; finding out whether it is necessary to activate a grinding operation based on the current number of welding points and a predetermined number of warning welding points; activating the grinding operation when it is found that it is necessary to activate the grinding operation; determining the actual grinding amount of the electrode tip based on a zero position calibration result of the electrode tip after completing each grinding operation; calculating the cumulative grinding amount of the electrode tip after multiple grinding operations by accumulating the actual grinding amount; comparing the cumulative grinding amount with a grinding threshold, and activating an operation to replace the electrode tip when the cumulative grinding amount exceeds or is equal to the grinding threshold.

[0009] In some embodiments, the method includes: before starting the grinding operation, causing the movable electrode to contact the counter electrode to perform a first zero position calibration; after completing the grinding operation, causing the movable electrode to contact the counter electrode to perform a second zero position calibration; and determining the actual grinding amount of the electrode head based on the results of the first zero position calibration and the results of the second zero position calibration.

[0010] In some embodiments, the method includes: comparing the actual grinding amount of the electrode tip with predetermined expected grinding parameters; if the actual grinding amount does not meet the expected grinding parameters, reactivating the grinding operation at least once until the actual grinding amount meets the expected grinding parameters.

[0011] In some embodiments, the expected grinding parameters involve a grinding amount numerical range. When the actual grinding amount of the electrode head falls within the grinding amount numerical range, it is determined that the actual grinding amount meets the expected grinding parameters; when the actual grinding amount of the electrode head exceeds the grinding amount numerical range, it is determined that the actual grinding amount does not meet the expected grinding parameters.

[0012] In some embodiments, the method includes: after completing the grinding operation, activating the performance testing operation, and when the performance testing operation is activated: causing the movable electrode to contact the paired electrode; causing a predetermined electrical test curve to be applied to the movable electrode and the paired electrode; obtaining an electrical response curve on the movable electrode and / or the paired electrode; ascertaining the performance of the electrode head based on the electrical test curve and the electrical response curve; when it is determined that the performance of the electrode head meets the expected performance, allowing further spot welding operations; when it is determined that the performance of the electrode head does not meet the expected performance: activating a prompt operation; and / or reactivating the grinding operation at least once until the performance of the electrode head meets the expected performance.

[0013] In some embodiments, the electrical test curve includes a voltage curve and the electrical response curve includes a current curve; or the electrical test curve includes a current curve and the electrical response curve includes a voltage curve.

[0014] In some embodiments, the method includes: determining the current resistance parameters of the electrode head based on the electrical test curve and the electrical response curve; comparing the current resistance parameters of the electrode head with the expected resistance parameters; allowing further spot welding operations when the current resistance parameters meet the expected resistance parameters; when the current resistance parameters do not meet the expected resistance parameters: activating a prompt operation; and / or reactivating a grinding operation at least once until the current resistance parameters meet the expected resistance parameters.

[0015] In some embodiments, the method includes: ascertaining a deviation parameter by which a current resistance parameter deviates from a desired resistance parameter; and adaptively adjusting a grinding parameter for a reactivated grinding operation based on the deviation parameter.

[0016] In some embodiments, the method includes: obtaining the number of welding points for a workpiece to be welded; and obtaining a corresponding number of warning welding points according to the number of welding points of the workpiece to be welded.

[0017] In some embodiments, the method includes: detecting a real-time image of the electrode head; determining the distance between the working end surface of the electrode head and the lifeline mark set on the electrode head based on the real-time image; when the distance is less than or equal to a predetermined distance, activating an operation to replace the electrode head.

[0018] In some embodiments, the method includes: generating an electrode tip remaining life indicator for display on a display interface based on a current accumulated grinding amount and a grinding threshold.

[0019] According to a second aspect of the present invention, a control device for grinding an electrode tip of a spot welding gun is proposed, characterized in that the control device comprises: at least one storage module configured to store a series of computer executable instructions; and at least one processing module configured to execute a series of computer executable instructions, wherein the series of computer executable instructions, when executed by the processing module, causes the processing module to execute the method according to some embodiments of the present invention.

[0020] According to a third aspect of the present invention, a system for grinding an electrode tip of a spot welding gun is proposed, characterized in that the system comprises: a robot on which a spot welding gun is mounted; a grinding device having a grinding tool for grinding the electrode tip of the spot welding gun; and a control device according to the present invention, the control device being configured to communicate with the robot and the grinding device so as to control the operation of the robot and the operation of the grinding device.

[0021] In some embodiments, the robot has a servo motor for driving a movable electrode of the spot welding gun and a position sensor for measuring the position of the movable electrode of the spot welding gun, and the robot is configured to: when performing a grinding operation, move the spot welding gun toward the grinding device with the help of the servo motor so that the electrode head of the movable electrode and / or the counter electrode of the spot welding gun is supported at a to-be-grinded position; when performing zero position calibration, move the movable electrode of the spot welding gun toward the counter electrode with the help of the servo motor so that the movable electrode contacts the counter electrode, and measure the position of the movable electrode with the help of the position sensor; and / or when performing a performance test, move the movable electrode of the spot welding gun toward the counter electrode with the help of the servo motor so that the movable electrode contacts the counter electrode, apply a predetermined electrical test curve to the movable electrode and the counter electrode with the help of a power supply, and detect the electrical response curve on the movable electrode and / or the counter electrode with the help of a sensor.

[0022] In some embodiments, the system includes a display interface that communicates with the control device, and the display interface is configured to display the following information: the accumulated grinding amount of the electrode tip; the remaining life indicator of the electrode tip; and / or a real-time image of the electrode tip taken by the robot's camera.

[0023] In some embodiments, the control device is configured to: when it is found that the cumulative grinding amount is less than the grinding amount threshold or the remaining life index of the electrode head is greater than the life index threshold, generate a first display instruction and send the first display instruction to the display interface; when it is found that the cumulative grinding amount is greater than or equal to the grinding amount threshold or the remaining life index of the electrode head is less than or equal to the life index threshold, generate a second display instruction and send the second display instruction to the display interface; and the display interface is configured to: generate a first management display scheme based on the received first display instruction so as to display a first prompt on the display interface; generate a second management display scheme based on the received second display instruction so as to display a second prompt that is different from the first prompt on the display interface.

[0024] In some embodiments, the display interface has a human-machine interaction control area, through which the display of the display interface, the operation of the robot and the operation of the grinding device can be intervened. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other aspects and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments in conjunction with the accompanying drawings, which illustrate the principles of the present invention by way of example. It should be noted that the drawings are not necessarily drawn to scale.

[0026] Figure 1 is a schematic block diagram of a system for grinding an electrode tip of a spot welding gun according to some embodiments of the present invention.

[0027] Figure 2 yes Figure 1 Schematic cross-sectional view of the electrode tip in FIG.

[0028] Figure 3 yes Figure 1 Schematic diagram of the spot welding gun system.

[0029] Figure 4 is an exemplary flow chart of a method for grinding an electrode tip of a spot welding gun according to some embodiments of the present invention.

[0030] Figure 5 It is a further extension of the method according to some embodiments of the present invention, which includes additional performance testing operations. DETAILED DESCRIPTION

[0031] The present invention will be described below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, it should be understood that the present invention can be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the present invention more complete and fully illustrate the scope of the present invention to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide more additional embodiments.

[0032] It should be understood that the terms used herein are only used to describe specific embodiments and are not intended to limit the present invention. All terms (including technical terms and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. For the sake of simplicity and / or clarity, well-known functions or structures may not be described in detail.

[0033] Herein, the term "A or B" includes "A and B" and "A or B" rather than exclusively including only "A" or only "B", unless specifically stated otherwise.

[0034] In this document, the term "exemplary" means "used as an example, instance or illustration". Any implementation described as an example herein is not necessarily to be construed as preferred or advantageous over other implementations. Moreover, the present invention is not limited by any stated or implied theory given in the above technical field, background technology, summary of the invention or detailed description.

[0035] In addition, for reference purposes only, the terms "first", "second" and the like may also be used herein, and "first" and "second" may also refer to multiple "firsts" and "seconds". For example, the terms "first", "second" and other such numerical terms referring to structures or elements do not imply a sequence or order unless the context clearly indicates otherwise.

[0036] It should also be understood that when the term "include / comprise" is used in this article, it indicates the presence of the indicated features, integrals, steps, operations, units and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, units and / or components and / or their combinations. Unless otherwise defined, all terms (including technical terms and scientific terms) are used in this article according to their general meaning in the field to which the examples belong.

[0037] Next, various aspects according to the present invention will be described in detail with reference to the accompanying drawings.

[0038] First reference Figure 1 , shows a schematic block diagram of a system for grinding the electrode tip 23 of a spot welding gun 20 according to some embodiments of the present invention, namely a grinding system 100. The grinding system 100 of the present application can be understood as an automated system capable of performing a grinding operation on the electrode tip 23 of the spot welding gun 20, for example, the working end surface 233 of the electrode tip 23.

[0039] like Figure 1 As shown, the grinding system 100 may include: a robot 10 , a spot welding gun 20 mounted on the robot 10 , a grinding device 30 arranged adjacent to the robot 10 , a control device 40 interacting with the robot 10 and the grinding device 30 , and an optional display interface 50 .

[0040] The robot 10 can be configured as a multi-joint robot, and the spot welding gun 20 can be, for example, mounted or attached to a manipulation portion, such as a wrist, of the robot 10. The position and posture of the spot welding gun 20 can be flexibly changed by driving a servo motor on the robot 10. Thus, the spot welding gun 20 can be flexibly positioned at a workpiece during a welding operation or at a grinding device 30 during a grinding operation.

[0041] exist Figure 1 A C-type spot welding gun 20 is exemplarily shown in FIG. Without limitation thereto, the robot 10 may also be equipped with or attached with a plurality of other devices such as Figure 3 X-type spot welding gun shown. Figure 1The spot welding gun 20 in the embodiment may include a gun arm, a movable electrode 21 and a matching electrode 22. The movable electrode and the matching electrode respectively include an electrode rod and the electrode head that can be assembled to the electrode rod. The gun arm may be assembled or attached to the manipulator of the robot 10. The movable electrode 21 may be mounted on one end of the gun arm, and the movable electrode 21 may be driven by a servo motor assembled in the gun arm. The matching electrode 22 may be mounted on the other end of the gun arm opposite to the movable electrode 21. In some embodiments, the matching electrode 22 may be movably mounted on the gun arm, that is, not only the movable electrode 21 but also the matching electrode 22 may move independently. In some embodiments, the matching electrode 22 is fixedly mounted on the gun arm, that is, the matching electrode 22 cannot move independently.

[0042] In some embodiments, the movable electrode 21 and the counter electrode 22 can be respectively configured as columnar electrodes extending along the same axis. The movable electrode 21 can be mounted on the gun arm in a manner that it can move linearly along the axis. That is, the movable electrode 21 can be driven by the servo motor to move not only toward the counter electrode 22 but also away from the counter electrode 22. The spot welding gun 20 squeezes the workpiece 33 clamped between the movable electrode 21 and the counter electrode 22, especially two overlapped workpieces (see Figure 3 ), and on the other hand, a current loop is formed between the movable electrode 21 and the counter electrode 22 so that current flows through each electrode, thereby melting the contact portions of the workpieces with each electrode, thereby locally joining the workpieces.

[0043] Figure 2 A schematic cross-sectional view of an exemplary electrode head 23 is shown, and the electrode head 23 can be an electrode head 23 installed, especially threadedly connected to the movable electrode 21, or an electrode head 23 installed, especially threadedly connected to the matching electrode 22, without limitation herein. It should be understood that the electrode head 23 can be implemented in various ways and is not limited to the specific examples described herein. For example, the electrode head 23 can be configured as a flat-head electrode head 23, a ball-head electrode head 23, a pointed-head electrode head 23, a round-head electrode head 23, or an electrode head 23 of other shapes. In some embodiments, the electrode head 23 can be configured as a chromium-zirconium-copper electrode head 23. In some embodiments, the electrode head 23 can be configured as a copper electrode head 23.

[0044] like Figure 2As shown, the electrode head 23 may include a working portion 231 and a connecting portion 232, wherein the working portion 231 is configured to implement the actual spot welding operation, and the connecting portion 232 is configured to be detachably assembled to the electrode rod. With the repeated use of the spot welding gun 20, the working end face 233 of the working portion 231 of the electrode head 23 of the spot welding gun 20 may undergo undesirable deformation and wear under the action of heat and electricity, and may form an undesirable oxide film or gray phase layer, thereby reducing the current density of the electrode head 23 when the spot welding gun 20 is used, thereby reducing the welding quality. Therefore, at this time, it is necessary to implement targeted grinding on the working end face 233 of the electrode head 23 of the spot welding gun 20, so as to reconstruct the working end face 233 configuration of the electrode head 23 (for example, R50 convex or R100 convex) and remove the oxide film or gray phase layer that may be generated. However, in order to ensure good welding performance, the grindable amount of the electrode head 23 is relatively limited, and thus the number of times the electrode head 23 can be grinded is relatively limited. Once the grinding limit is reached, the electrode tip 23 needs to be replaced with a new one.

[0045] The grinding device 30 can be arranged adjacent to the robot 10 to allow the grinding device 30 to cooperate with the robot 10 and the spot welding gun 20. In some embodiments, the grinding device 30 may include a first grinding device 31 for grinding the movable electrode 21 and a second grinding device 32 for grinding the counter electrode 22. In some embodiments, a rotatably driven grinding tool can be used as the grinding device. Advantageously, the grinding device 30 can be equipped with a grinding tool with different grinding properties to allow different degrees and / or different methods of grinding to be implemented for the electrode head 23, thereby improving the grinding accuracy and / or effect for the electrode head 23.

[0046] In some embodiments, the first grinding device 31 and the second grinding device 32 may be arranged side by side on the grinding device 30. In some embodiments, the first grinding device 31 and the second grinding device 32 may be arranged oppositely on the grinding device 30, that is, the first grinding device 31 may be arranged on the upper side of the grinding device 30, and the second grinding device 32 may be arranged on the opposite lower side of the grinding device 30. In some embodiments, a plurality of first grinding devices 31 and a plurality of second grinding devices 32 may be arranged on the grinding device 30 to allow grinding operations on a plurality of pairs of electrode tips 23. Advantageously, the grinding device 30 may simultaneously perform grinding operations on the electrode tips 23 on the movable electrode 21 and the counter electrode 22 of the corresponding spot welding gun 20, thereby improving the grinding efficiency. Of course, the grinding device 30 may also perform grinding operations on the electrode tips 23 on the movable electrode 21 and the counter electrode 22 of the corresponding spot welding gun 20 separately.

[0047] The control device 40 may be configured to communicate with the robot 10 (together with the spot welding gun 20 mounted on the robot 10) and the grinding device 30 so as to control the operation of the robot 10 and the operation of the grinding device 30. For example, the control device 40 may control the operation of the robot 10 and the operation of the grinding device 30 based on the operation data from the robot 10 and the operation data from the grinding device 30.

[0048] Advantageously, the control device 40 may have a display interface 50 or communicate with the display interface 50 so as to allow the operating status of the grinding system 100 to be displayed on the display interface 50. Additionally or alternatively, the control device 40 may have other external devices or communicate with other external devices so as to output various alarm messages and notification signals to the external devices. The external device may be a portable smart device, such as a smart phone, etc.

[0049] In the present application, the control device 40 should be broadly understood as a variety of types of control devices 40. In some embodiments, the control device 40 can be configured as a local control device 40, such as a PLC controller (i.e., a programmable logic controller) or a control host. The control device 40 can be centrally stored in a central control room or distributedly deployed in a control cabinet next to the corresponding controlled object. In some embodiments, the control device 40 can be configured as a remote control device 40, such as a cloud server. The control device 40 may include at least one storage module 41, configured to store a series of computer executable instructions; and at least one processing module 42, configured to execute a series of computer executable instructions, wherein the series of computer executable instructions, when executed by the processing module, causes the processing module to execute the method according to some embodiments of the present invention. In addition, at least one storage module may also be configured to store predetermined data records, such as operating data from a grinding device 30, a robot 10, etc.

[0050] Next reference Figure 4 , describes in detail an exemplary flow chart of a method for grinding the electrode tip 23 of a spot welding gun 20 according to some embodiments of the present invention. It should be understood that the steps of the method presented below are intended to be illustrative. In some embodiments, the method can be completed with one or more additional undescribed steps, and / or without one or more of the steps discussed. In addition, the order of the steps of the method shown in the figure and described below is not intended to be limiting.

[0051] like Figure 4 As shown, the method for grinding the electrode tip 23 of the spot welding gun 20 may include the following steps:

[0052] S10: Find out the current number of welding points of the electrode head 23;

[0053] S20: Finding out whether it is necessary to activate the grinding operation according to the current number of welding points and the predetermined number of warning welding points;

[0054] S30: activating the grinding operation when it is found that the grinding operation needs to be activated;

[0055] S40: after each grinding operation is completed, determining the actual grinding amount of the electrode tip 23 based on the result of the zero position calibration of the electrode tip 23;

[0056] S50: calculating the cumulative grinding amount of the electrode tip 23 after multiple grinding operations by accumulating the actual grinding amount;

[0057] S60: Compare the accumulated grinding amount with the grinding threshold value, and when the accumulated grinding amount exceeds or is equal to the grinding threshold value, activate the operation of replacing the electrode head 23.

[0058] In the present application, the electrode head 23 can usually only implement a predetermined number of welding points, i.e., the maximum number of welding points, in each grinding cycle (i.e., the period from the end of one grinding operation to the start of the next grinding operation). Once the electrode head 23 reaches the maximum number of welding points, it indicates that the electrode head 23 cannot meet the predetermined welding performance with a great probability (e.g., a probability of 90% or more than 95%). However, if it is directly determined based on the maximum number of welding points whether the grinding operation needs to be activated, it may cause the welding performance implemented by the electrode head 23 at least in the last welding work cycle to be substandard. This results in reduced welding quality.

[0059] In order to timely or in advance predict that the electrode head 23 is about to reach the maximum number of welding points, the number of warning welding points of the electrode head 23 can be set. The number of warning welding points can be preset, for example, determined based on historical data. Therefore, once the electrode head 23 reaches the number of warning welding points, it is necessary to perform targeted grinding operations as soon as possible. In some embodiments, the number of warning welding points can be used to warn the number of welding points that have been implemented by the electrode head 23. That is, when the number of welding points that have been implemented exceeds or equals the number of warning welding points, it can be determined that the grinding operation needs to be activated, otherwise the grinding operation does not need to be activated. Accordingly, the current number of welding points of the electrode head 23 can be the number of welding points that have been implemented in a grinding cycle. In some embodiments, the number of warning welding points can be used to warn the remaining number of welding points that have not been implemented by the electrode head 23. That is, when the remaining number of welding points is less than or equal to the number of warning welding points, it can be determined that the grinding operation needs to be activated, otherwise the grinding operation does not need to be activated. Alternatively, the current number of welding points of the electrode head 23 can be the remaining number of welding points. In the present application, by introducing a comparison between the current welding point number and the warning welding point number, it is possible to efficiently and timely find out whether the electrode tip 23 needs to be ground.

[0060] In a further improved embodiment, the number of warning welding points can be set according to the characteristics of the workpiece to be welded. Advantageously, the following method steps can be specified in the method: obtaining the number of welding points for a workpiece to be welded; obtaining the corresponding number of warning welding points according to the number of welding points of the workpiece to be welded. In some embodiments, the number of warning welding points can be set to be greater than or equal to a multiple of the number of welding points n of the workpiece to be welded, such as 2n+1, thereby ensuring that the welding performance of the electrode head 23 is up to standard at least in the last welding working cycle. For example, if the number of welding points of the workpiece to be welded is 10 spot weldings, the number of warning welding points can be set to 21 spot weldings. Advantageously, when the workpiece to be welded changes, the corresponding number of warning welding points can be updated accordingly so as to obtain a self-adaptive number of warning welding points.

[0061] In order to improve the utilization rate of the electrode tip 23 as much as possible while ensuring good welding performance, so as to reduce the consumption of the electrode tip 23 and thus save production costs. In the present application, it is advantageous to introduce a comparison between the cumulative grinding amount and the grinding threshold to efficiently and accurately find out whether the electrode tip 23 needs to be replaced. To this end, it is critical to accurately detect the grinding amount of each grinding operation. In addition, it is also desirable to detect the grinding amount of each grinding operation in a simple and efficient manner.

[0062] In the present application, advantageously, the actual grinding amount of the electrode tip 23 is determined based on the result of the zero position calibration of the electrode tip 23. Here, the position where the electrode tip 23 on the movable electrode 21 is in direct contact with the electrode tip 23 on the counter electrode 22 is determined as the zero position. In order to further improve the accuracy of the zero position calibration, it can be stipulated that the position where the electrode tip 23 on the movable electrode 21 is in direct contact with the electrode tip 23 on the counter electrode 22 and the contact pressure reaches a predetermined value is determined as the zero position.

[0063] In a further improved embodiment, the following method steps may be specified in the method: before starting the grinding operation, the movable electrode 21 is brought into contact with the counter electrode 22, or more precisely, the electrode head 23 of the movable electrode 21 is brought into contact with the electrode head 23 of the counter electrode 22, so as to perform a first zero position calibration; after completing the grinding operation, the movable electrode 21 is brought into contact with the counter electrode 22, so as to perform a second zero position calibration; and the actual grinding amount of the electrode head 23 is determined based on the results of the first zero position calibration and the results of the second zero position calibration.

[0064] Advantageously, the actual grinding amount of the movable electrode 21, more precisely the actual grinding amount of the electrode tip 23 of the movable electrode 21, can be determined first, and then the actual grinding amount of the counter electrode 22 can be determined. The following method steps can be provided in the method: before starting the grinding operation of the movable electrode 21, the movable electrode 21 is brought into contact with the counter electrode 22 to perform a first zero calibration; after completing the grinding operation of the movable electrode 21, the movable electrode 21 is brought into contact with the counter electrode 22 to perform a second zero calibration; based on the first zero calibration and the second zero calibration, the actual grinding amount of the electrode tip 23 of the movable electrode 21 is determined. After determining the actual grinding amount of the electrode head 23 of the movable electrode 21, before starting the grinding operation on the counter electrode 22, the movable electrode 21 is brought into contact with the counter electrode 22 to perform a first zero position calibration; after completing the grinding operation on the counter electrode 22, the movable electrode 21 is brought into contact with the counter electrode 22 to perform a second zero position calibration; the actual grinding amount of the electrode head 23 of the counter electrode 22 is determined based on the first zero position calibration and the second zero position calibration.

[0065] It is simple and efficient to determine the actual grinding amount of the electrode tip 23 by means of zero calibration. When performing zero calibration, the movable electrode 21 of the spot welding gun 20 can be moved toward the counter electrode 22 by means of a servo motor so that the movable electrode 21 contacts the counter electrode 22, and the position of the movable electrode 21 or the movement amount of the movable electrode 21 is measured by means of a position sensor. The actual grinding amount of the electrode tip 23 can be determined by the difference in movement amount between the first zero calibration before the grinding operation and the second zero calibration after the grinding operation.

[0066] In a further improved embodiment, the following method steps may be specified in the method: comparing the actual grinding amount of the electrode head 23 with the predetermined expected grinding parameters; in the case where the actual grinding amount does not meet the expected grinding parameters, reactivating the grinding operation at least once until the actual grinding amount meets the expected grinding parameters. Advantageously, the expected grinding parameters involve a grinding amount numerical range, and when the actual grinding amount of the electrode head 23 falls within the grinding amount numerical range, it is determined that the actual grinding amount meets the expected grinding parameters; when the actual grinding amount of the electrode head 23 exceeds the grinding amount numerical range, it is determined that the actual grinding amount does not meet the expected grinding parameters. By introducing a closed-loop control mechanism for the grinding amount, each grinding operation of the electrode head 23 is made more precise, thereby effectively improving the utilization rate of the electrode head 23, reducing the consumption of the electrode head 23 and thus saving production costs.

[0067] Additionally or alternatively, in order to ensure that the electrode tip 23 maintains good welding performance after grinding, a performance testing operation may be advantageously introduced after the grinding operation is completed. Figure 5As shown, the method for grinding the electrode tip 23 of the spot welding gun 20 may include additional performance testing operations and may advantageously include the following steps:

[0068] S41: Prompting the movable electrode 21 to contact with the counter electrode 22, more specifically, prompting the electrode tip 23 of the movable electrode 21 to contact with the electrode tip 23 of the counter electrode 22;

[0069] S42: Prompting application of a predetermined electrical test curve to the movable electrode 21 and the counter electrode 22, for example, applying a predetermined electrical test curve between the movable electrode rod 21 and the counter electrode rod 22;

[0070] S43: Acquire electrical response curves on the movable electrode 21 and the counter electrode 22;

[0071] S44: Finding out the performance of the electrode head 23 based on the electrical test curve and the electrical response curve;

[0072] S45: When it is found that the performance of the electrode tip 23 meets the expected performance, further spot welding operation is allowed;

[0073] S46: When it is found that the performance of the electrode tip 23 does not meet the expected performance: activate the prompting operation and / or reactivate the grinding operation at least once until the performance of the electrode tip 23 meets the expected performance.

[0074] In some embodiments, the electrical test curve may be a voltage curve, and the electrical response curve may be a current curve. That is, a predetermined voltage is applied between the movable electrode 21 and the counter electrode 22 by means of the voltage source 25, and the current flowing through the movable electrode 21 and the counter electrode 22 is detected by means of the current sensor 27, see Figure 3 .

[0075] In some embodiments, the electrical test curve may be a current curve, and the electrical response curve may be a voltage curve. That is, a predetermined current is applied between the movable electrode 21 and the counter electrode 22 by means of the current source 26, and the voltage on the movable electrode 21 and the counter electrode 22 is detected by means of the voltage sensor 28, see Figure 3 .

[0076] In a further improved embodiment, the following method steps may be specified in the method: determining the current resistance parameters of the electrode head 23 based on the electrical test curve and the electrical response curve; comparing the current resistance parameters of the electrode head 23 with the expected resistance parameters; allowing further spot welding operations if the current resistance parameters meet the expected resistance parameters; if the current resistance parameters do not meet the expected resistance parameters: activating a prompt operation; and / or reactivating the grinding operation at least once until the current resistance parameters meet the expected resistance parameters.

[0077] Since the welding performance of the electrode head 23 is closely related to the resistance value of the electrode head 23, good welding performance requires suitable resistance parameters. To this end, the present application advantageously introduces a comparison between the current resistance parameter of the electrode head 23 and the expected resistance parameter, so that the resistance value of the electrode head 23 is as consistent as possible with the expected resistance parameter, thereby ensuring good welding performance.

[0078] Additionally or alternatively, the following method steps may be provided in the method: for a specific electrical test curve, an expected electrical response curve may be generated, the expected electrical response curve may be generated based on an expected resistance parameter; the performance of the electrode head 23 is determined by introducing a deviation between the actual electrical response curve and the expected electrical response curve. Additionally or alternatively, based on the deviation between the actual electrical response curve and the expected electrical response curve, the grinding parameters for the reactivated grinding operation are adaptively adjusted. The grinding parameters may include, for example, grinding time, grinding angle, grinding tool, etc.

[0079] In a further improved embodiment, the following method steps may be provided in the method: finding out the deviation parameter of the current resistance parameter from the expected resistance parameter; adaptively adjusting the grinding parameter for the reactivated grinding operation based on the deviation parameter. Thus, the electrode head 23 may obtain electrical properties that are more consistent with the expected resistance parameter after the grinding operation.

[0080] Additionally or alternatively, the following method steps may be provided in the method:

[0081] S70: Detecting a real-time image of the electrode head 23;

[0082] S80: Determine the distance between the working end surface 233 of the electrode head 23 and the lifeline mark set on the electrode head 23 based on the real-time image;

[0083] S90: When the distance is less than or equal to the predetermined distance, the operation of replacing the electrode head 23 is activated.

[0084] The introduction of real-time images allows additional monitoring of the operation of replacing the electrode head 23 from a visual inspection. This further ensures that the electrode head 23 can be replaced in a timely manner without affecting the welding quality. To this end, a lifeline mark, such as a lifeline, can be set on the electrode head 23. Advantageously, a visual highlight setting can be applied to the lifeline mark to improve the accuracy of visual inspection.

[0085] Additionally or alternatively, a method step S100 may be provided in the method: in particular after each grinding operation, an electrode head 23 remaining life indicator for display on the display interface 50 is generated based on the current accumulated grinding amount and the grinding threshold, for example, the electrode head 23 remaining life indicator displayed as a percentage.

[0086] In the present application, the grinding threshold may be predetermined in advance, for example, determined according to a lifeline mark set on the electrode head 23. In some embodiments, the grinding threshold may be the distance between the initial working end face 233 of the electrode head 23 and the lifeline mark or a portion thereof.

[0087] In some embodiments, the display interface 50 may be configured to display the following information: the accumulated grinding amount of the electrode head 23 ; an indicator of the remaining life of the electrode head 23 ; and / or a real-time image of the electrode head 23 captured by a camera of the robot 10 .

[0088] By displaying various information on the display interface 50, the staff can intuitively understand the operating status of each electrode head 23, which is very beneficial for production management and scheduling. Advantageously, the display interface 50 has a human-machine interaction control area, through which the display of the display interface 50, the operation of the robot 10 and the operation of the grinding device 30 can be intervened.

[0089] Additionally or alternatively, the following method steps may be specified in the method: when it is found that the cumulative grinding amount is less than the grinding amount threshold or the remaining life index of the electrode head 23 is greater than the life index threshold, a first display instruction is generated and the first display instruction is sent to the display interface 50; when it is found that the cumulative grinding amount is greater than or equal to the grinding amount threshold or the remaining life index of the electrode head 23 is less than or equal to the life index threshold, a second display instruction is generated and the second display instruction is sent to the display interface 50. Accordingly, the display interface 50 may be configured to: generate a first management display scheme based on the received first display instruction so as to display a first prompt on the display interface 50; generate a second management display scheme based on the received second display instruction so as to display a second prompt different from the first prompt on the display interface 50.

[0090] The invention being thus described, it will be obvious that the invention may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. A method for grinding an electrode tip of a spot welding gun, wherein the spot welding gun comprises a movable electrode and a counter electrode paired with the movable electrode, wherein the movable electrode and the counter electrode respectively comprise detachably assembled electrode tips, characterized in that: The method comprises: Find out the current number of welding points of the electrode tip; Find out whether the grinding operation needs to be activated based on the current number of welds and the pre-determined number of warning welds; activating the grinding operation if activation of the grinding operation is determined to be necessary; After each grinding operation is completed, the actual grinding amount of the electrode tip is determined based on the zero position calibration of the electrode tip; calculating the cumulative grinding amount of the electrode tip after multiple grinding operations by accumulating the actual grinding amount; The accumulated grinding amount is compared with the grinding threshold, and when the accumulated grinding amount exceeds or is equal to the grinding threshold, the electrode head replacement operation is activated.

2. The method according to claim 1, characterized in that The method comprises: Prior to commencing a grinding operation, bringing the movable electrode into contact with the counter electrode to perform a first zero calibration; After the grinding operation is completed, the movable electrode is brought into contact with the counter electrode to perform a second zero calibration; The actual grinding amount of the electrode tip is determined based on the first zero position calibration and the second zero position calibration.

3. The method according to claim 1, characterized in that: The method comprises: comparing the actual grinding amount of the electrode tip with the predetermined desired grinding parameters; When the actual grinding amount does not meet the expected grinding parameters, reactivating the grinding operation at least once until the actual grinding amount meets the expected grinding parameters; Preferably, the desired grinding parameters involve a range of grinding amount values, When the actual grinding amount of the electrode tip falls within the grinding amount value range, it is determined that the actual grinding amount meets the expected grinding parameters; When the actual grinding amount of the electrode tip exceeds the grinding amount value range, it is determined that the actual grinding amount does not meet the expected grinding parameters.

4. The method according to claim 1, characterized in that The method comprises: After completing the grinding operation, activate the performance test operation, and while the performance test operation is activated: Prompting the movable electrode to contact the counter electrode; causing application of a predetermined electrical test profile to the movable electrode and the counter electrode; Acquiring an electrical response curve on the movable electrode and / or the counter electrode; Find out the performance of the electrode tip based on the electrical test curve and the electrical response curve; When it is found that the performance of the electrode tip meets the expected performance, further spot welding operations are allowed; When it is found that the performance of the electrode tip does not meet the expected performance: Activate a reminder action; and / or Reactivate the grinding operation at least once until the performance of the electrode tip meets the desired performance, Preferably, the electrical test curve comprises a voltage curve, and the electrical response curve comprises a current curve; or the electrical test curve comprises a current curve, and the electrical response curve comprises a voltage curve.

5. The method according to claim 4, characterized in that The method comprises: Determine the current resistance parameter of the electrode head based on the electrical test curve and the electrical response curve; comparing the current resistance parameter of the electrode tip with the expected resistance parameter; In the case where the current resistance parameters meet the expected resistance parameters, further spot welding operations are allowed; When the current resistance parameters do not meet the expected resistance parameters: Activate a reminder action; and / or The grinding operation is activated again at least once until the current resistance parameters match the desired resistance parameters.

6. The method according to claim 5, characterized in that The method comprises: Find out the deviation parameter of the current resistance parameter from the expected resistance parameter; Grinding parameters for the reactivated grinding operation are adaptively adjusted based on the deviation parameter.

7. The method according to any one of claims 1 to 6, characterized in that The method comprises: Obtain the number of welding points for a workpiece to be welded; The corresponding number of warning welding points is obtained according to the number of welding points of the workpiece to be welded.

8. The method according to any one of claims 1 to 6, characterized in that The method comprises: Detect the real-time image of the electrode tip; Determine the distance between the working end face of the electrode head and the lifeline mark set on the electrode head based on the real-time image; When the distance is less than or equal to a predetermined distance, the electrode tip replacement operation is activated.

9. The method according to any one of claims 1 to 6, characterized in that The method comprises: An electrode tip remaining life indicator is generated based on the current accumulated grinding amount and the grinding threshold for display on the display interface.

10. A control device for grinding the electrode tip of a spot welding gun, characterized in that: The control device comprises: at least one storage module configured to store a series of computer executable instructions; and at least one processing module configured to execute a series of computer executable instructions, Wherein, the series of computer executable instructions, when executed by a processing module, causes the processing module to perform the method according to any one of claims 1 to 9.

11. A system for grinding an electrode tip of a spot welding gun, characterized in that: The system comprises: A robot, on which a spot welding gun is mounted; A grinding device having a grinding tool for grinding an electrode tip of a spot welding gun; The control device according to claim 10, the control device being configured to communicate with the robot and the grinding device so as to control the operation of the robot and the operation of the grinding device.

12. The system according to claim 11, characterized in that The robot has a servo motor for driving a movable electrode of a spot welding gun and a position sensor for measuring a position of the movable electrode of the spot welding gun, and is configured to: When performing the grinding operation, the spot welding gun is moved toward the grinding device by means of a servo motor so that the electrode tip of the movable electrode and / or the counter electrode of the spot welding gun is supported at a position to be ground; When performing zero calibration, a movable electrode of the spot welding gun is moved toward a counter electrode by means of a servo motor so that the movable electrode contacts the counter electrode, and a position sensor is used to measure a position of the movable electrode; and / or When performing the performance test, the movable electrode of the spot welding gun is moved toward the counter electrode by means of a servo motor so that the movable electrode contacts the counter electrode, a predetermined electrical test curve is applied to the movable electrode and the counter electrode by means of a power supply, and the electrical response curve on the movable electrode and / or the counter electrode is detected by means of a sensor.

13. The system according to claim 11, characterized in that The system includes a display interface in communication with a control device, the display interface being configured to display the following information: Cumulative grinding amount of electrode tip; Remaining life indicator of the electrode tip; and / or Live image of the electrode tip captured by the robot's camera.

14. The system according to claim 13, characterized in that The control device is configured to: When it is found that the accumulated grinding amount is less than the grinding amount threshold or the electrode head remaining life index is greater than the life index threshold, a first display instruction is generated and sent to the display interface; When it is found that the accumulated grinding amount is greater than or equal to the grinding amount threshold or the electrode head remaining life index is less than or equal to the life index threshold, a second display instruction is generated and sent to the display interface; And the display interface is configured as: generating a first management display scheme based on the received first display instruction so as to display a first prompt on the display interface; A second management display scheme is generated based on the received second display instruction, so as to display a second prompt different from the first prompt on the display interface.

15. The system according to any one of claims 11 to 14, characterized in that The display interface has a human-machine interaction control area, through which the display of the display interface, the operation of the robot and the operation of the grinding device can be intervened.

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