PLC-based Automatic Welding Method, System and Storage Medium for Ball Valves

Abstract

The present application relates to the field of welding technology, and discloses a ball valve automatic welding method, system and storage medium based on a PLC. The method is based on a ball valve placed at the center of a turntable, and obtains the specification parameters of the ball valve; takes the variable diameter height direction of the ball valve as the height position, and takes the position of the ball valve on the rotation plane as the angle position; defines the center position of the side plane of the ball valve as the first height and the first angle; drives the welding torch to move from the set initial position to the first height; drives the turntable to rotate to the first angle; locates the starting position of welding on the side surface of the ball valve, the height position of the starting position is the first height, and the angle position of the starting position is the second angle; wherein, the absolute value of the difference between the first angle and the second angle is greater than a preset reference angle value; drives the welding torch to strike an arc at the starting position, the turntable rotates, and the welding torch performs surfacing on the surface of the ball valve; the welding torch changes lanes at the second angle. This solution helps to realize the automatic welding of ball valves and improve production efficiency.

Description

Technical Field

[0001] The present application relates to the field of welding technology, and particularly to a ball valve automatic welding method, system and storage medium based on PLC. Background Art

[0002] A ball valve is a valve that rotates around the axis of the ball valve. In order to improve wear resistance, corrosion resistance or hardness, wear-resistant materials, corrosion-resistant materials or high-hardness materials need to be surfacing welded on the surface of the ball valve.

[0003] In the field of surfacing welding on the outer surface of a ball valve, the existing process usually starts the arc at the center height position of the ball valve. When choosing the side close to the machine as the starting arc point, the operation mode of welding forward rotation combined with post-wire feeding is adopted. During the welding process, when the welding torch runs to the edge position of the side channel, manual operation is required to stop welding. Then, the ball valve is rotated by manually turning the turntable to move the workpiece to the other edge of the side channel. Then, the X-axis displacement is manually adjusted to make the tungsten needle of the welding torch close to the surface of the workpiece, and the arc is restarted to continue surfacing welding. The outer surface surfacing welding is completed by repeating the above operations multiple times. This process relies on manual control of the position conversion of the starting arc point and the stopping arc point, and frequent adjustment of equipment parameters and mechanical position calibration are required, which has extremely high requirements for the proficiency and experience of operators.

[0004] However, the existing method has technical defects: manual intervention results in discrete distribution of the starting arc and stopping arc positions. During multi-layer surfacing welding, the welding process needs to be interrupted multiple times, and the manual positioning error will accumulate layer by layer, which is extremely likely to cause welding defects such as pores, slag inclusions, and poor fusion, and is likely to form an uneven fusion transition zone on the surface of the surfacing layer, seriously affecting the bonding strength and corrosion and wear resistance of the outer surface surfacing layer of the ball valve. Summary of the Invention

[0005] In order to realize the automatic welding of the ball valve surface and improve production efficiency, the present application provides a ball valve automatic welding method, system and storage medium based on PLC.

[0006] In the first aspect, the present application provides a ball valve automatic welding method based on PLC, adopting the following technical solution:

[0007] A ball valve automatic welding method based on PLC includes the following steps:

[0008] Based on the ball valve placed at the center of the turntable, obtain the specification parameters of the ball valve;

[0009] Take the variable diameter height direction of the ball valve as the height position, and the position of the ball valve on the rotation plane as the angular position; define the central position of the side plane of the ball valve as the first height and the first angle;

[0010] Drive the welding torch to move from the set initial position to the first height;

[0011] Drive the turntable to rotate to the first angle;

[0012] At the starting position of the positioning weld on the side of the ball valve, the height position of the starting position is the first height, and the angular position of the starting position is the second angle; wherein, the absolute value of the difference between the first angle and the second angle is greater than a preset reference angle value;

[0013] Drive the welding torch to strike an arc at the starting position, drive the turntable to rotate, and the welding torch performs surfacing on the surface of the ball valve; drive the welding torch to change lanes at the second angle.

[0014] By adopting the above technical solution, through a series of PLC-based automated operations, such as obtaining the specification parameters of the ball valve, driving the precise movement of the welding torch and the turntable, etc., the automation of the surface welding of the ball valve is realized. Compared with the existing process that relies on manual frequent control of the conversion of the starting and stopping points of welding, frequent adjustment of equipment parameters and calibration of mechanical positions, the manual operation links are reduced, and there is no need for operators to repeatedly perform complex manual operations, saving a large amount of time, thus significantly improving the production efficiency. By accurately calculating the starting and stopping points of the arc, they are evenly and smoothly distributed at the edge position of the side channel. By defining the height position and angular position of the ball valve and accurately positioning the starting position and lane-changing position based on this, the error accumulation caused by inaccurate manual positioning can be effectively avoided, thereby reducing the occurrence of welding defects such as pores, slag inclusions, and poor fusion, and improving the bonding strength and corrosion and wear resistance of the surfacing layer on the outer surface of the ball valve.

[0015] Optionally, in the step of positioning the starting position of the weld on the side of the ball valve, the following sub-steps are further included:

[0016] A first optional position is defined on the curved surface on one side of the side plane of the ball valve, and a second optional position is defined on the curved surface on the other side of the side plane;

[0017] Calculate the distance between the first optional position and the position of the welding machine to which the welding torch belongs as the first distance, and calculate the distance between the second optional position and the position of the welding machine to which the welding torch belongs as the second distance; wherein, the first distance is less than the second distance;

[0018] If the first optional position is selected as the starting position, the starting position is close to the welding machine and the rotation direction of the turntable is controlled as the first direction; if the second optional position is selected as the starting position, the starting position is far from the welding machine and the rotation direction of the turntable is controlled as the second direction.

[0019] By adopting the above technical solution, by calculating the distances between the first optional position and the second optional position and the welding machine, and selecting the starting position and the corresponding rotating direction of the turntable according to the distances, the welding process can be made more in line with the process requirements, thereby optimizing the welding forming effect. When the starting position is close to the welding machine, the turntable is selected to rotate forward for welding. This combination can make the feeding and melting of the welding wire more uniform during the welding process, which is beneficial to forming a beautiful and flat weld seam. On the contrary, when the starting position is far from the welding machine, reverse welding is adopted, which can also ensure the stability of the welding process and guarantee the forming quality of the weld seam.

[0020] Optionally, the feeding direction after aligning the welding torch with the ball valve is taken as the X-axis, the variable diameter height direction of the ball valve is taken as the Y-axis, the rotating direction of the ball valve on the rotating plane is taken as the T-axis, and the central position of the side plane of the ball valve is defined as the zero point of the Y-axis and 90 degrees of the T-axis;

[0021] Locate the starting position on the side curved surface of the ball valve, where the Y-axis of the starting position is zero and the T-axis of the starting position is zero degree.

[0022] By adopting the above technical solution, by constructing a three-dimensional coordinate system, during the welding process, the calculation of the position of the welding torch, the rotation angle of the ball valve, and different height positions becomes extremely intuitive and simple. The PLC system can quickly and accurately calculate the parameters corresponding to each action based on this clear coordinate system, greatly simplifying the control logic. The precise coordinate definition provides an accurate positioning reference for the welding process. During the multi-layer surfacing process, the starting and ending positions of each layer of welding can be accurately set according to this coordinate system. Since the position of each welding can be accurately corresponding to this coordinate system, the cumulative error caused by unclear position definition is avoided. Taking the side curved surface welding as an example, the clear starting position (zero point of the Y-axis, zero degree of the T-axis) ensures the consistency of the starting arc position each time, making the starting points of each layer of weld seams accurately coincide, thereby effectively reducing the generation of welding defects, improving the bonding strength and surface quality of the surfacing layer, and ensuring the high precision and stability of the welding process.

[0023] Optionally, in the step of driving the welding torch to change lanes at the second angle, the following sub-steps are further included:

[0024] Start arc from the starting position and start welding, and drive the turntable to rotate;

[0025] Stop arc when the welding torch touches the first side of the side plane;

[0026] Control the welding torch to retreat and drive the turntable to rotate;

[0027] When the welding torch passes the second side of the side plane, control the welding torch to approach the ball valve and start arc;

[0028] Drive the turntable to continue rotating. When the welding torch passes through the second angle, change lanes along the variable diameter height direction.

[0029] By adopting the above technical solution, by accurately stopping the arc when the welding torch touches the first side of the side plane, controlling the boundary of the single-pass welding area, avoiding edge welding defects, and then through the backward movement of the welding torch, the rotation of the turntable and the restart of the arc, ensuring a smooth transition of the welding on both sides of the side plane, reducing multi-layer surfacing defects, and improving the welding quality; its lane-changing process is automatically executed according to the preset logic, reducing manual intervention, improving the degree of welding automation and production efficiency; when the welding torch passes through the second angle, change lanes along the variable diameter height direction, optimizing the welding path, reducing ineffective actions, enhancing the welding efficiency and reducing costs; at the same time, this design has strong flexibility, can automatically adjust the action parameters according to different ball valve specification parameters, enhancing the adaptability and versatility of the equipment.

[0030] Optionally, in the step of surfacing the surface of the ball valve with the welding torch, the following sub-steps are further included:

[0031] Judge whether the welding torch passes through the side plane according to the Y-axis height of the welding torch. If not, drive the turntable to rotate and keep the welding state of the welding torch until the Y-axis height of the welding torch reaches the preset set height;

[0032] Among them, when the welding torch passes through the second angle, change lanes along the variable diameter height direction.

[0033] By adopting the above technical solution, through the fine control of the welding torch during the surfacing process, many significant advantages are demonstrated. Judging whether the welding torch passes through the side plane based on the Y-axis height of the welding torch can ensure a stable welding state when welding in the non-side plane area. As long as the welding torch does not reach the preset set height, the turntable continues to rotate and the welding torch welds stably, ensuring the continuity of the welding process, avoiding unnecessary starting and stopping of the arc, effectively reducing the generation of welding defects, and improving the welding quality. At the same time, it is clear that when the welding torch passes through the second angle, change lanes along the variable diameter height direction, making the welding path planning more scientific and reasonable. On the basis of ensuring full coverage of the welding area, it avoids ineffective welding actions and greatly improves the welding efficiency.

[0034] Optionally, in the step of changing lanes, the following sub-steps are further included:

[0035] The specification parameters include the side plane diameter, the main ball diameter, and the lane-changing arc length;

[0036] Calculate the ratio of the side plane diameter to the main ball diameter to obtain the first gain value;

[0037] Calculate the ratio of the lane-changing arc length to the preset reference arc length to obtain the second gain value;

[0038] Adjust the speed of the torch lane change in a positive correlation according to the first gain value; the larger the first gain value, the greater the speed of the torch lane change; the smaller the first gain value, the smaller the speed of the torch lane change.

[0039] Adjust the rotation speed of the turntable during lane change in a positive correlation according to the second gain value; the larger the second gain value, the greater the rotation speed of the turntable; the smaller the second gain value, the smaller the rotation speed of the turntable.

[0040] By adopting the above technical solution, the first gain value is obtained by calculating the ratio of the side plane diameter to the main ball diameter, and the speed of the torch lane change is adjusted in a positive correlation accordingly, which can ensure that during the welding of ball valves with different specifications, the torch lane change process is adapted to the sphere size. When the first gain value is large, that is, when the side plane diameter is relatively large compared to the main ball diameter, the speed of the torch lane change is increased, which can make the welding process more conform to the actual structure of the ball valve, avoid insufficient welding or over-welding caused by improper lane change speed, and thus improve the welding quality and the consistency of the weld seam. Based on the ratio of the lane change arc length to the preset reference arc length (the second gain value), the rotation speed of the turntable is adjusted in a positive correlation, effectively improving the welding efficiency. When the second gain value is large, which means the lane change arc length is long, the rotation speed of the turntable is increased, so that the ball valve can rotate to the appropriate position faster per unit time, reducing the waiting time during the welding process, and the torch can quickly enter the next welding area to achieve efficient welding.

[0041] Optionally, the method further includes the following steps:

[0042] Obtain the quality data of multiple latest processed and completed historical products;

[0043] Calculate the average value of the multiple quality data;

[0044] Calculate the quality ratio of the average value to the preset reference quality value;

[0045] Adjust the rotation speed of the turntable when the torch passes through the side plane in a positive correlation according to the quality ratio; the larger the quality ratio, the greater the rotation speed of the turntable; the smaller the quality ratio, the smaller the rotation speed of the turntable.

[0046] By adopting the above technical solution, based on the quality data of multiple recently processed historical products, calculate the quality ratio of its average value to the preset reference quality value, and accordingly adjust the rotation speed of the turntable when the welding torch passes through the side plane in a positive correlation. When the quality ratio is larger, that is, when the quality of the historical products is better, increase the rotation speed of the turntable. This means that in the welding process, the production mode for high-quality products is effectively learned from and strengthened. With the improvement of the quality of historical products, the rotation speed of the turntable is correspondingly increased, which can accelerate the production rhythm on the premise of ensuring the welding quality. When starting arc welding from the side, an appropriate increase in the rotation speed can reduce the welding time of a single product, enabling the equipment to process more products per unit time.

[0047] Optionally, the method further includes the following steps:

[0048] Calculate the change trend value of the multiple quality data;

[0049] According to the change trend value, adjust the rotation speed of the turntable when the welding torch approaches the side plane in a positive correlation; the larger the change trend value, the larger the rotation speed of the turntable; the smaller the change trend value, the smaller the rotation speed of the turntable.

[0050] By adopting the above technical solution, when the quality of historical products shows an upward trend, that is, when the change trend value is larger, increase the rotation speed of the turntable. This adjustment can better adapt to the rhythm requirements of high-quality product production. For example, when stopping arc welding from the side, a faster rotation speed can make the heat input during welding more reasonable and the cooling speed of the weld seam more ideal, thereby promoting the perfect fusion of the welding material and the base material and effectively improving the quality and aesthetics of the weld seam. On the contrary, if the quality shows a downward trend, reducing the rotation speed can make the welding process more delicate, reduce defects caused by too fast speed, ensure the stability of the welding quality, fit the actual situation of product quality change, and achieve precise control. Dynamically adjusting the rotation speed according to the change trend of quality data can flexibly control the production efficiency on the basis of ensuring the welding quality.

[0051] In a second aspect, the present application provides a PLC-based automatic ball valve welding system, adopting the following technical solution:

[0052] A PLC-based automatic ball valve welding system includes a processor, and the processor executes the steps of the PLC-based automatic ball valve welding method described in any one of the above.

[0053] In a third aspect, the present application provides a storage medium, adopting the following technical solution:

[0054] A storage medium stores a program, and when the program is executed by a processor, it realizes the steps of the PLC-based automatic ball valve welding method described in any one of the above.

[0055] In summary, the present application includes at least one of the following beneficial technical effects:

[0056] Automation is achieved with the help of a PLC, getting rid of the dependence on manual control for frequently switching the starting and stopping points of welding, adjusting equipment parameters, and calibrating mechanical positions, saving a significant amount of time.

[0057] The positions of the starting and stopping points are accurately calculated, making them evenly and smoothly distributed on the edge of the side channel, avoiding the accumulation of manual positioning errors, reducing welding defects such as porosity, slag inclusion, and poor fusion, and enhancing the bonding strength, corrosion resistance, and wear resistance of the surfacing layer on the outer surface of the ball valve. During multi-layer surfacing, the layers are closely connected, and the quality of the surfacing layer is reliable.

[0058] A three-dimensional coordinate system is constructed with the feeding direction of the welding torch as the X-axis, the variable diameter height direction of the ball valve as the Y-axis, and the rotation plane rotation direction as the T-axis. The central position of the side plane is defined as the key coordinate point, simplifying the calculation of the position of the welding torch, the rotation angle of the ball valve, and different height positions by the PLC system, providing an accurate positioning reference for welding, reducing welding defects, and ensuring high precision and stability during the welding process. Description of the Drawings

[0059] Figure 1 is a step diagram of an automatic welding method for a ball valve based on a PLC.

[0060] Figure 2 is a coordinate diagram of ball valve welding. Detailed Embodiments

[0061] The following details the embodiments of the present application, and examples of the embodiments are shown in the drawings.

[0062] In the description of this specification, the description referring to the terms "certain embodiments", "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0063] The embodiments of the present application disclose an automatic welding method for a ball valve based on a PLC, referring to Figure 1 and Figure 2 , including the following steps:

[0064] Precisely place the ball valve at the center of the turntable. Through the built-in sensors and data acquisition module, quickly and accurately obtain various specification parameters of the ball valve. These parameters cover the diameter of the ball valve, the side plane size, the reduced diameter height, and other key data closely related to the welding process. For example, for different models of ball valves, the main ball diameter varies from dozens of millimeters to several meters, and the ratio of the side plane diameter to the main ball diameter is also different.

[0065] Construct a position coordinate system. Set the reduced diameter height direction of the ball valve as the height position, represented by the Y-axis. Define the position of the ball valve on the rotating plane as the angular position, recorded by the T-axis. Define the center position of the side plane of the ball valve as the first height and the first angle, that is, the zero point of the Y-axis and the ninety degrees of the T-axis. Through the clear coordinate definition method, it provides an accurate positioning reference for subsequent welding operations. For example, during the multi-layer surfacing process, the starting and ending positions of each layer of welding can be accurately set according to this coordinate system, avoiding the accumulation of welding errors caused by vague position definition.

[0066] After obtaining the parameters and establishing the coordinate system, the control system issues an instruction to drive the welding torch to move smoothly and precisely from the preset initial position along the established motion trajectory to the first height. In this process, parameters such as the movement speed and acceleration of the welding torch are accurately calculated and controlled to ensure that it can quickly and accurately reach the specified position. At the same time, the turntable also rotates precisely to the first angle according to the preset angle value under the drive of the motor.

[0067] On the side of the ball valve, the system locates the starting position of welding according to the preset algorithm. The height position of this starting position remains the first height, and the angular position is set as the second angle. The absolute value of the difference between the first angle and the second angle is greater than the preset reference angle value. By reasonably setting this angle difference, the welding torch can better avoid the side plane of the ball valve during the welding process.

[0068] When all the preliminary preparations are completed, the system issues an instruction to drive the welding torch to start arcing at the starting position. At this time, the turntable starts to rotate at a constant speed, driving the ball valve to rotate synchronously, and the welding torch continuously performs surfacing operations on the surface of the ball valve. During the entire welding process, the system real-time monitors key parameters such as the position of the welding torch, welding current, voltage, and the rotation speed of the turntable, and makes dynamic adjustments according to the preset control strategy to ensure the stability and consistency of the welding process. When the welding torch runs to the second angle, the system issues another instruction to drive the welding torch to perform a lane change operation according to the pre-planned path. This lane change process is also carefully designed to ensure that the welding torch can smoothly switch from the current welding path to the next path and continue to perform efficient and high-quality surfacing on other areas of the ball valve.

[0069] Through automation, the manual operation links are greatly reduced. The operator only needs to complete simple tasks such as placing the ball valve and inputting parameters in the early stage, and the subsequent welding process is automatically completed by the system. This not only saves a large amount of time and significantly improves production efficiency, but also makes the starting and stopping points of the arc evenly and smoothly distributed at the edge position of the side channel through precise calculation. For example, during multi-layer surfacing welding, the system can accurately control the starting and stopping points of each layer of welding according to the preset algorithm, ensuring tight and uniform connection between the welds of each layer, and effectively avoiding the accumulation of errors caused by inaccurate manual positioning. This precise positioning method can effectively reduce the occurrence of welding defects such as porosity, slag inclusion, and poor fusion, thus significantly improving the bonding strength and corrosion and wear resistance of the surfacing layer on the outer surface of the ball valve.

[0070] To ensure a better welding process, the method further includes the following steps:

[0071] Define specific positions on the curved surfaces on both sides of the side plane of the ball valve. Precisely delimit the first optional position on the curved surface on one side of the side plane, and at the same time, define the second optional position on the curved surface on the other side of the side plane. The determination of these two positions takes into account various factors such as the structural characteristics of the ball valve, welding process requirements, and the layout of the welding machine equipment. Especially according to the selection of the starting point position, different surfacing treatment methods are selected.

[0072] Calculate the distance between the first optional position and the position of the welding gun belonging to the welding machine, and define it as the first distance; similarly, calculate the distance between the second optional position and the welding machine position, that is, the second distance. During the actual measurement process, use a high-precision laser ranging sensor or a machine vision-based measurement system to ensure the accuracy of distance measurement. Moreover, the selection of the two optional positions makes the first distance less than the second distance.

[0073] Select the starting point position and control the rotation direction of the turntable according to the calculated distance results. If the first optional position is selected as the starting point position after comprehensive evaluation, this starting point position is relatively close to the welding machine. To match this position feature, the control system will automatically adjust and control the rotation direction of the turntable to the first direction, usually set as the forward rotation direction. When the turntable rotates forward, combined with the working parameters of the welding machine, it can make the feeding and melting process of the welding wire more uniform during the welding process. During the welding process, the stable output of current and voltage, plus the forward rotation of the turntable driving the uniform rotation of the ball valve, enables the welding wire to be deposited on the surface of the ball valve at an appropriate speed and angle, which is conducive to forming a beautiful and flat weld. For example, when welding a thin-walled ball valve, this combination of being close to the welding machine and the turntable rotating forward can better control the heat input during welding, avoid deformation of the ball valve caused by heat influence, and ensure the quality and appearance of the weld.

[0074] Conversely, if the second optional position is selected as the starting position, this position is far from the welding machine. In this case, the control system will set the rotation direction of the turntable to the second direction, generally the reverse direction. When the starting position is far from the welding machine, adopting the reverse welding method can also ensure the stability of the welding process. Since it is far from the welding machine, the arc length and heat distribution during the welding process will be different, and the reverse rotation of the turntable can make the ball valve pass under the welding torch at an appropriate speed, ensuring a more reasonable match between the welding current, voltage, and wire feeding speed. In this way, even under the unfavorable condition that the starting position is far from the welding machine, the forming quality of the weld can be fully guaranteed. For example, when welding a large-diameter ball valve, the second optional position may be more conducive to fully covering the welding area. Through reverse welding, the welding material can be evenly cladded on the surface of the ball valve to form a high-quality weld, effectively avoiding welding defects that may occur due to the remote position.

[0075] By calculating the distances between the first and second optional positions and the welding machine, and cleverly selecting the starting position and the corresponding turntable rotation direction according to the distance, this method can make the welding process more in line with the complex and changeable process requirements in all aspects, fundamentally optimize the welding forming effect, and greatly improve the quality and reliability of ball valve welding.

[0076] Take the feeding direction after aligning the welding torch with the ball valve as the X-axis, and the value of the X-axis represents the vertical distance between the welding torch and the Y-axis; take the variable diameter height direction of the ball valve as the Y-axis, and the rotation direction of the ball valve on the rotation plane as the T-axis to construct a three-dimensional coordinate system. Define the center position of the side plane of the ball valve as the zero point of the Y-axis and 90 degrees of the T-axis.

[0077] Locate the starting position on the side curved surface of the ball valve. The Y-axis of the starting position is zero, and the T-axis of the starting position is zero degree. That is to say, the starting point of welding starts from the side curved surface of the ball valve and is not close to the edge of the side plane. Since the ball valve is a spherical structure as a whole, in order to ensure the welding quality, the welding is carried out from bottom to top. After half of the ball valve surface is welded, the ball valve will reverse the angle and start welding again, also by building up the weld from bottom to top.

[0078] Find the center position of the side channel through the welding torch, set the zero point of the Y-axis here, and set the T-axis to 90 degrees. This is convenient for automatically calculating the arc starting and stopping positions and the change of the ball valve diameter in the PLC through the Y-axis height. Setting the T-axis to 90 degrees is convenient for realizing the slide shoe lane change within the build-up welding area.

[0079] By precisely corresponding the position of each welding to this coordinate system, the cumulative error caused by unclear position definition is effectively avoided. The starting point of each layer of weld can accurately coincide with the preset position (zero point of the Y-axis, zero degree of the T-axis), ensuring the high precision and stability of the welding process. This not only effectively reduces the generation of welding defects such as porosity, slag inclusion, and lack of fusion, but also significantly improves the bonding strength of the surfacing layer.

[0080] In the step of driving the welding torch to change lanes at the second angle, the following sub-steps are also included:

[0081] Welding starts, and the welding torch arcs at the positioned starting point. At this moment, the current is instantaneously switched on, and the arc shines between the welding torch and the surface of the ball valve. The high temperature quickly melts the welding material, and the surfacing operation on the surface of the ball valve begins. At the same time, the turntable rotates smoothly at a preset stable speed under the drive of the motor. This enables the welding torch to weld evenly and continuously along the curved surface of the ball valve, ensuring the quality and consistency of the weld.

[0082] When the welding torch gradually moves during the welding process and touches the first side of the side plane, the system immediately issues an instruction, and the welding torch quickly stops arcing. Through precise sensor feedback and algorithm operation, the system can cut off the current in a timely manner when the welding torch reaches the first side of the side plane, causing the arc to go out. Precise arc stopping can accurately control the boundary of the single welding area, effectively avoiding welding defects such as undercut and burn-through caused by excessive welding at the edge of the side plane.

[0083] After arc stopping, the control system controls the welding torch to retreat along a specific path. The parameters such as the retreat distance and speed of the welding torch are closely related to the welding process and the structural characteristics of the ball valve. In this embodiment, the welding torch retreats to a set distance from the side plane of the ball valve to avoid the structures on the side plane of the ball valve. While the welding torch is retreating, the turntable continues to rotate, driving the ball valve to continue rotating. Such a design enables the ball valve to continue moving to a suitable position during the retreat of the welding torch, preparing for the subsequent re-arcing. For example, in some cases, the retreat distance of the welding torch may need to be adjusted according to the width of the side plane and the characteristics of the welding material to ensure that the welding parameters can remain in the optimal state during the re-arcing.

[0084] When the welding torch passes the second side of the side plane, the control system issues an instruction again to control the welding torch to approach the ball valve again and quickly arc. At this time, the arc is lit again, and the welding operation continues. During the re-arcing process, the system precisely controls parameters such as the position of the welding torch, current, and voltage to ensure that the arc can be smoothly lit at the new position and the welding process can be smoothly connected, avoiding welding defects.

[0085] The turntable continues to rotate at a preset speed, driving the ball valve to rotate continuously. When the welding torch passes through the second angle during rotation, the system, according to the preset logic, drives the welding torch to perform a lane-changing operation along the variable diameter height direction, that is, the Y-axis direction, namely to rise by a set distance. During the lane-changing process, the system will comprehensively consider various factors, such as the specification parameters of the ball valve, the thickness of the current welding layer, and the welding quality requirements, etc., to precisely control the moving speed, direction of the welding torch and the adjustment of welding parameters. For example, for ball valves of different specifications, their variable diameter heights are different, and the moving distance and speed of the welding torch during lane-changing will also change accordingly. Through this precise control, the welding path can be optimized, unnecessary ineffective actions can be reduced, and the welding efficiency can be greatly improved. In traditional welding processes, due to the lack of such precise lane-changing control, ineffective actions such as the welding torch moving empty and repeated welding often occur, which not only wastes time and welding materials, but also may affect the welding quality. And this method can significantly shorten the welding time and reduce production costs on the premise of ensuring the welding quality through precise lane-changing operations.

[0086] In the step of surfacing the surface of the ball valve with the welding torch, the following sub-steps are also included:

[0087] During the progress of the entire surfacing process, the system constantly monitors the operating state of the welding torch closely, and obtains the Y-axis height data of the welding torch in real time according to the update of the welding torch lane-changing data. Based on these precise data, the system can quickly and accurately judge whether the welding torch has passed through the side plane of the ball valve. In the actual welding scenario, when the welding torch starts to move from the initial position to the surface of the ball valve and starts welding, its Y-axis height is at a relatively low value. As the turntable drives the ball valve to rotate continuously, the welding torch welds along the curved surface of the ball valve, and the Y-axis height also changes gradually. As the height of the welding torch rises, there is no area of the side plane on the curved surface to be welded on the surface of the ball valve. That is, after surfacing one circle, directly change lanes, drive the turntable to rotate at a stable speed uniformly, and there is no need for the welding torch to retreat, stop arc and start arc in the middle. At the same time, the welding torch maintains the current welding state, and key parameters such as welding current, voltage and wire feeding speed remain constant. This process ensures that the welding in the non-side plane area can be carried out smoothly and continuously. When the Y-axis height of the welding torch has not reached the preset height, it means that the surfacing of the upper hemisphere part of the ball valve is completed. Among them, during the process without stopping the arc, when the system monitors that the welding torch has passed through the second angle during rotation, it will immediately drive the welding torch to perform a lane-changing operation along the variable diameter height direction, that is, the Y-axis direction, according to the preset program logic. This method can significantly shorten the welding cycle while ensuring the welding quality, providing strong support for enterprises to improve production efficiency and reduce production costs.

[0088] In the step of changing lanes, the following sub-steps are also included:

[0089] The specification parameters include the side plane diameter, the main ball diameter, and the lane-changing arc length; these parameters comprehensively reflect the structural characteristics of the ball valve and the key dimensions involved in the welding process. The side plane diameter determines the size of the side area of the ball valve, the main ball diameter reflects the overall size of the sphere, and the lane-changing arc length is directly related to the arc length covered by the lane-changing operation during welding. In the actual production of ball valves, these parameters will show a wide range of variations due to different models, uses, and design requirements of the ball valves.

[0090] Calculate the ratio of the side plane diameter to the main ball diameter to obtain the first gain value.

[0091] Calculate the ratio of the lane-changing arc length to the preset reference arc length to obtain the second gain value.

[0092] Adjust the speed of the welding torch lane-changing in a positive correlation according to the first gain value; the larger the first gain value, the greater the speed of the welding torch lane-changing; the smaller the first gain value, the smaller the speed of the welding torch lane-changing. As shown in the case of Table 1, when the first gain value is large, it means that the side plane diameter is relatively large compared to the main ball diameter. At this time, in order to make the welding process closely fit the actual structure of the ball valve and avoid insufficient welding or over-welding, the system will automatically increase the speed of the welding torch lane-changing. In the welding of large ball valves, due to the large side plane area, if the speed of the welding torch lane-changing is too slow, it will lead to too long welding time in the side plane area, which may cause local overheating, resulting in welding deformation or reduced welding quality; while increasing the lane-changing speed can make the welding process more efficiently and evenly cover the side plane area, ensuring the quality and consistency of the weld. On the contrary, when the first gain value is small, the system will correspondingly reduce the speed of the welding torch lane-changing to ensure the fineness and accuracy of welding.

[0093] Table 1 Lane-changing speed table for ball valves of various specifications

[0094]

[0095] Adjust the rotation speed of the turntable during lane-changing in a positive correlation according to the second gain value; the larger the second gain value, the greater the rotation speed of the turntable; the smaller the second gain value, the smaller the rotation speed of the turntable. As shown in the case of Table 2, when the second gain value is large, it indicates that the lane-changing arc length is long. In this case, increasing the rotation speed of the turntable has significant advantages. For example, in the welding of ball valves with special structures, the lane-changing arc length may account for a large proportion of the entire welding path. By increasing the rotation speed of the turntable, the ball valve can be rotated to the appropriate position faster per unit time, greatly reducing the waiting time during the welding process. The welding torch can quickly enter the next welding area to achieve efficient welding. On the contrary, when the second gain value is small, the rotation speed of the turntable will also be correspondingly reduced to ensure that the welding process can proceed smoothly and accurately within a short lane-changing arc length, avoiding the generation of welding defects due to too fast rotation speed.

[0096] Table 2 Rotary Table Speed Chart for Ball Valves in Multiple Situations

[0097]

[0098] Through this method based on precise calculation and dynamic adjustment, during the welding process of ball valves with different specifications, the optimal matching between the torch lane-changing speed and the rotary table speed can be achieved. This not only ensures the perfect adaptation of the welding process to the sphere size and structure, effectively improves the welding quality, but also significantly enhances the welding efficiency by optimizing the lane-changing process, providing strong technical support for the high-quality and high-efficiency production of ball valves.

[0099] The method further includes the following steps:

[0100] The system will regularly and automatically obtain the quality data of multiple recently processed historical products. These quality data are extensive and accurate in source, including but not limited to the appearance quality inspection data of the weld, such as the flatness of the weld, records of defects such as pores and cracks; the internal quality data of the weld, such as the fusion condition and inclusion distribution inside the weld obtained through non-destructive testing; and the quality data related to the product performance, like the overall sealing performance test results and pressure resistance strength values after the ball valve is welded. By collecting these data comprehensively, the comprehensive quality status of the product can be accurately reflected.

[0101] After obtaining a large amount of quality data, the system immediately starts the internal data analysis program to deeply process these data. Calculate the average value of multiple quality data. For example, if the weld strength data of 10 recently completed ball valve products are collected, which are 500MPa, 520MPa, 490MPa, 510MPa, 530MPa, 505MPa, 515MPa, 485MPa, 525MPa, 508MPa respectively, the system will accumulate these data, that is, 500 + 520 + 490 + 510 + 530 + 505 + 515 + 485 + 525 + 508 = 5088MPa, and then divide by the number of data 10 to get an average value of 508.8MPa. By calculating the average value, the interference of individual abnormal data on the overall quality assessment can be effectively eliminated, making the quality assessment result more representative and stable.

[0102] Next, the system will compare the calculated average value with a preset reference quality value through an operation to obtain a quality ratio. This preset reference quality value is not determined randomly, but is determined based on a comprehensive consideration of various factors such as long-term production practice experience, industry standards, and product design requirements. For example, for a specific model of ball valve, its design requirement is that the weld strength should reach above 500 MPa. Based on the data of high-quality products produced in the past and the industry-wide standards, the reference quality value is set at 500 MPa. If the calculated average quality value is 508.8 MPa, then the quality ratio is 508.8÷500 = 1.0176.

[0103] Subsequently, based on this quality ratio, the system makes a positive correlation adjustment to the rotation speed of the turntable when the welding torch passes through the side plane. The larger the quality ratio, the better the quality of the historical products. At this time, the system will automatically increase the rotation speed of the turntable. This operation is of great significance in the actual welding process. For example, in the side starting arc welding process, when the rotation speed of the turntable increases, the ball valve can rotate to the appropriate position faster per unit time, enabling the welding torch to complete the welding of the side plane area more quickly. On the premise of ensuring the welding quality, the production rhythm is greatly accelerated. Suppose that originally, it took 10 minutes to complete the welding of the side plane of a ball valve at a certain rotation speed. As the quality of the historical products improves and the quality ratio increases, after the system increases the rotation speed of the turntable, it only takes 8 minutes to complete the same side plane welding, and the welding time of a single product is significantly reduced. This means that the equipment can process more products per unit time, greatly improving the production efficiency. In this way, the system can continuously learn from and strengthen the production mode of high-quality products, achieve a virtuous cycle in the production process, and continuously improve product quality and production efficiency.

[0104] The method further includes the following steps:

[0105] During the continuous progress of welding production, the system regularly calculates the change trend values of multiple quality data. To obtain comprehensive and accurate quality data, the system not only collects detailed records of the appearance quality indicators of the weld, such as the flatness of the weld, the presence of pores, undercutting and other defects, but also covers the internal quality inspection results of the weld, such as the key information of the internal fusion state and inclusion distribution of the weld obtained by non-destructive testing technology, and also includes the relevant data of the overall performance of the product, such as the sealing performance test value of the ball valve after welding and the actual detection result of the pressure resistance strength. By widely collecting these multi-dimensional quality data, a solid data foundation is provided for subsequent analysis.

[0106] On the premise of having a large amount of quality data, the system uses advanced data analysis algorithms to calculate the trend value. For example, the linear regression analysis method is used to arrange the quality data over a period of time in chronological order to construct a data sequence. Assume that in 10 consecutive production batches, the weld strength data of the product is 480MPa, 490MPa, 500MPa, 515MPa, 530MPa, 540MPa, 550MPa, 565MPa, 580MPa, and 590MPa. Through linear regression analysis, the slope of the data sequence is calculated, and the slope can be used as the trend value of the quality data. In this example, the calculated slope is a positive value, indicating that the product quality is showing an upward trend. This scientific calculation method can accurately reflect the trend of quality data changes over time or production batches.

[0107] Based on the calculated change trend value, the system will automatically adjust the rotation speed of the turntable when the welding gun approaches the side plane. When the historical product quality shows an upward trend, that is, the larger the change trend value, the system will decisively increase the rotation speed of the turntable. Taking the key link of side arc stop welding as an example, at a higher turntable speed, the ball valve can rotate to the welding position at a faster speed, which makes the heat input distribution during welding more uniform and reasonable. Since the welding material can cover a larger area more quickly per unit time, the heat can be transferred to the base material more evenly, avoiding local overheating or overcooling. At the same time, the faster rotation speed also makes the cooling speed of the weld more ideal. At the appropriate cooling rate, the welding material and the base material can fully diffuse and fuse to form a denser and more uniform weld structure, thereby effectively improving the quality and aesthetics of the weld. The weld surface is smoother and flatter, and the internal structure is tighter, which greatly enhances the strength and corrosion resistance of the weld.

[0108] On the contrary, if the quality data shows a downward trend, that is, when the trend value is small, the system will reduce the speed of the turntable in time. In this case, reducing the speed can make the welding process more refined. During the welding process, the welding gun has more time to accurately operate each welding point, and the welding current, voltage and feeding speed of the welding material can be more accurately controlled. This can effectively reduce various welding defects that may be caused by excessive speed, such as pores, lack of fusion, cracks, etc. By reducing the speed, the stability of the welding process is ensured, and the welding quality can be maintained at a relatively high level, which is in line with the actual situation of product quality changes and realizes precise control of the welding process.

[0109] By dynamically adjusting the rotary table speed according to the changing trend of quality data, this method can flexibly control the production efficiency while ensuring the welding quality. When the product quality is on the rise, increasing the speed can make full use of the good production situation, speed up the production rhythm, and increase the product output per unit time; while when the quality shows fluctuations or a downward trend, reducing the speed to ensure quality and avoid a large number of defective products caused by the pursuit of speed, thus finding the best balance between quality and efficiency and providing strong support for the enterprise to achieve efficient and stable production.

[0110] In the method of placing the ball valve at the center of the rotary table, the center of the circle can be corrected with the assistance of a welding torch. Method for correcting the center of the circle: First, move the crossbeam through the equipment operation panel so that the tungsten needle of the welding torch aligns with a point on the upper plane of the ball valve, then rotate the rotary table and finely adjust the position of the ball valve to make the ball valve concentric with the welding torch.

[0111] The embodiment of the present application also discloses a PLC-based automatic ball valve welding system, including a processor, and the processor executes the steps of the PLC-based automatic ball valve welding method described in any one of the above.

[0112] The embodiment of the present application also discloses a storage medium, in which a program is stored, and when the program is executed by the processor, it realizes the steps of the PLC-based automatic ball valve welding method described in any one of the above.

[0113] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. An automatic welding method for a ball valve based on a PLC, characterized in that, It includes the following steps: Based on the ball valve placed at the center of the turntable, obtain the specification parameters of the ball valve; Take the variable diameter height direction of the ball valve as the height position, and take the position of the ball valve on the rotation plane as the angular position; define the central position of the side plane of the ball valve as the first height and the first angle; Drive the welding torch to move from the set initial position to the first height; Drive the turntable to rotate to the first angle; Locate the starting position of welding on the side surface of the ball valve, the height position of the starting position is the first height, and the angular position of the starting position is the second angle; wherein, the absolute value of the difference between the first angle and the second angle is greater than the preset reference angle value; Drive the welding torch to strike an arc at the starting position, drive the turntable to rotate, and the welding torch surfacing-welds the surface of the ball valve; drive the welding torch to change lanes at the second angle; Obtain the quality data of multiple latest processed finished products; Calculate the average value of multiple quality data; Calculate the quality ratio of the average value to the preset reference quality value; Regulate the rotation speed of the turntable when the welding torch passes through the side plane in positive correlation with the quality ratio; the larger the quality ratio, the larger the rotation speed of the turntable; the smaller the quality ratio, the smaller the rotation speed of the turntable; Calculate the change trend value of multiple quality data; Regulate the rotation speed of the turntable when the welding torch approaches the side plane in positive correlation with the change trend value; the larger the change trend value, the larger the rotation speed of the turntable; the smaller the change trend value, the smaller the rotation speed of the turntable.

2. The automatic ball valve welding method based on PLC according to claim 1, wherein In the step of locating the starting position of welding on the side surface of the ball valve, it further includes the following sub-steps: A first optional position is defined on the curved surface on one side of the side plane of the ball valve, and a second optional position is defined on the curved surface on the other side of the side plane; Calculate the distance between the first optional position and the position of the welding machine to which the welding torch belongs as the first distance, and calculate the distance between the second optional position and the position of the welding machine to which the welding torch belongs as the second distance; wherein, the first distance is less than the second distance; If the first optional position is selected as the starting position, the starting position is close to the welding machine and control the rotation direction of the turntable as the first direction; if the second optional position is selected as the starting position, the starting position is far from the welding machine and control the rotation direction of the turntable as the second direction.

3. The automatic welding method of the ball valve based on PLC according to claim 1, wherein, Take the feeding direction after aligning the welding torch with the ball valve as the X-axis, take the variable diameter height direction of the ball valve as the Y-axis, take the rotation direction of the ball valve on the rotation plane as the T-axis, and define the central position of the side plane of the ball valve as the zero point of the Y-axis and ninety degrees of the T-axis; Locate the starting position on the side curved surface of the ball valve, the Y-axis of the starting position is zero, and the T-axis of the starting position is zero degrees.

4. The automatic ball valve welding method based on PLC according to claim 3, characterized in that, In the step of driving the welding torch to change lanes at the second angle, it further includes the following sub-steps: Strike an arc from the starting position, start welding, and drive the turntable to rotate; Stop the arc when the welding torch touches the first side of the side plane; Control the welding torch to retract and drive the turntable to rotate; When the welding torch passes through the second side of the side plane, control the welding torch to approach the ball valve and strike an arc; Drive the turntable to continue rotating. When the welding torch passes through the second angle, change lanes along the variable diameter height direction.

5. The automatic welding method for ball valves based on PLC according to claim 4, characterized in that, In the step of surfacing the surface of the ball valve with the welding torch, the following sub-steps are further included: Judge whether the welding torch passes through the side plane according to the Y-axis height of the welding torch. If not, drive the turntable to rotate and keep the welding state of the welding torch until the Y-axis height of the welding torch reaches the preset set height; Among them, when the welding torch passes through the second angle, change lanes along the variable diameter height direction.

6. The automatic welding method for a ball valve based on a PLC according to claim 1, characterized in that In the step of changing lanes, the following sub-steps are further included: The specification parameters include the side plane diameter, the main ball diameter and the lane-changing arc length; Calculate the ratio of the side plane diameter to the main ball diameter to obtain the first gain value; Calculate the ratio of the lane-changing arc length to the preset reference arc length to obtain the second gain value; Adjust the lane-changing speed of the welding torch in a positive correlation according to the first gain value; the larger the first gain value, the greater the lane-changing speed of the welding torch; the smaller the first gain value, the smaller the lane-changing speed of the welding torch; Adjust the rotation speed of the turntable during lane-changing in a positive correlation according to the second gain value; the larger the second gain value, the greater the rotation speed of the turntable; the smaller the second gain value, the smaller the rotation speed of the turntable.

7. A ball valve automatic welding system based on PLC, characterized in that, It includes a processor, and the processor executes the steps of the PLC-based automatic welding method for ball valves according to any one of claims 1-6.

8. A storage medium, characterized in that, A program is stored in the medium, and when the program is executed by the processor, the steps of the PLC-based automatic welding method for ball valves according to any one of claims 1-6 are realized.

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