A method for evaluating the stability of welding wire feeding

Abstract

This invention discloses a method for evaluating the stability of welding wire feeding, comprising the following steps: measuring the frictional resistance experienced by the welding wire at a set position during welding, and collecting the changes in the frictional resistance experienced by the welding wire at the set position during welding; measuring the real-time coordinates of the center point of the welding wire on a set plane during welding; obtaining the eccentricity of the welding wire center point and its change based on the real-time coordinates; obtaining the azimuth angle formed by the line connecting the welding wire center and the welding torch center and the positive welding direction, and its change based on the real-time coordinates; and evaluating the wire feeding stability during welding based on the changes in frictional resistance, eccentricity, and azimuth angle. This method not only improves the detection of axial feeding stability but also supplements the evaluation technology of the spatial position of the welding wire end, making the evaluation method more comprehensive and accurate. Furthermore, this method is easy to install and operate, and has high scalability.

Description

Technical Field

[0001] This invention relates to an evaluation method, and more particularly to a method for evaluating welding performance. Background Technology

[0002] In the welding processes of gas metal arc welding (GMAW) and submerged arc welding (SAW), the welding wire itself acts as the electrode to generate an electric arc; therefore, the wire feeding stability is crucial for welding quality. Wire feeding stability should encompass two aspects:

[0003] One aspect is the stability or uniformity of the feed direction, and some existing technologies have attempted to provide solutions to this.

[0004] For example, Chinese patent document CN108098120A, published on June 1, 2018, entitled "A Method for Evaluating the Stability of Welding Wire Feeding Speed," proposes a method for evaluating the stability of welding wire feeding speed. This method utilizes a component consisting of a laser diffuse reflection sensor, a counting / timing card, a computer, and a laser reflection grating sticker to transform the evaluation of wire feeding speed stability into the measurement of the rotational speeds of the wire feeding wheel and the straightening wheel, thereby achieving a quantitative evaluation of the stability of the welding wire feeding speed. This method is easy to implement and simple to install; however, it is a method for measuring the uniformity of wire feeding speed.

[0005] In principle, this method counts and converts time by attaching stickers to the wire feeding and straightening rollers. However, since the laser stickers themselves occupy a certain volume, their adhesion density is limited, which leads to a limited sampling frequency (i.e., measurement accuracy). Moreover, when the surface condition of the welding wire changes, especially when the welding wire has surface contamination such as oil or rust, the measured values ​​may not accurately reflect the actual wire feeding speed. For example, when there is oil on the welding wire surface, wire slippage may occur, and the actual wire feeding speed has decreased, but the wire feeding roller may still be rotating, thus still being able to obtain the wire feeding speed.

[0006] It can be seen that this stability testing method only considers the stability of the welding wire in the feeding direction, but fails to take into account the impact of changes in the spatial position of the welding wire on the welding process.

[0007] Another aspect of wire feeding stability is the spatial positional stability of the wire tip. In certain welding conditions, such as within a beveled workpiece, the height of the surfaces to be welded varies. The continuous changes in the relative position of the wire tip lead to constant shifts in the distance between the wire tip and the workpiece surface, causing fluctuations in welding voltage and current, thus affecting welding stability. Currently, the physical properties of the welding wire itself (GB / T8110-2020 "Solid Welding Wires of Non-Alloy Steel and Fine-Grained Steel for Gas Metal Arc Welding") and its tensile strength, as specified in engineering standards, can reflect the quality of wire feeding stability to some extent. However, judging based on these indicators is very indirect and requires extensive engineering experience.

[0008] It is evident that the current wire feeding stability testing technology mainly targets the uniformity of wire feeding speed. Its comprehensiveness is lacking, as it does not consider the impact of changes in the spatial position of the welding wire end on welding. Furthermore, its detection of the actual wire feeding speed may be inaccurate in certain situations. Summary of the Invention

[0009] The purpose of this invention is to provide a method for evaluating the stability of welding wire feeding. This method uses three indicators—frictional resistance, eccentricity, and azimuth angle—to reflect the stability of wire feeding during the welding process, thereby providing a comprehensive and accurate technical evaluation scheme for the stability testing of welding wire feeding.

[0010] To achieve the above objectives, the present invention provides a method for evaluating the stability of welding wire feeding, comprising the following steps:

[0011] The frictional resistance experienced by the welding wire at a set position during the welding process was measured, and the changes in the frictional resistance experienced by the welding wire at the set position during the welding process were collected.

[0012] Measure the real-time coordinates of the center point of the welding wire on a set plane during the welding process;

[0013] The eccentricity of the welding wire center point and the change of the eccentricity are obtained based on the real-time coordinates.

[0014] Based on the real-time coordinates, the azimuth angle formed by the line connecting the center of the welding wire and the center of the welding gun and the positive welding direction, as well as the change of the azimuth angle, are obtained.

[0015] The wire feeding stability during the welding process is evaluated based on the changes in frictional resistance, eccentricity, and azimuth angle.

[0016] The method for evaluating the stability of welding wire feeding described in this invention measures the axial wire feeding stability during the welding process by measuring frictional resistance; the radial wire feeding stability during the welding process by measuring the change in the eccentricity of the wire center relative to the welding torch center on a set plane; and the circumferential wire feeding stability during the welding process by measuring the change in the azimuth angle between the line connecting the wire center and the welding torch center on the set plane and the positive welding direction. Finally, the wire feeding stability during the welding process is reflected by three indicators: frictional resistance (characterizing axial), eccentricity (characterizing radial), and azimuth angle (characterizing circumferential), thus providing a comprehensive and accurate technical evaluation scheme for the stability detection of welding wire feeding.

[0017] Furthermore, in the method for evaluating the stability of welding wire feeding described in this invention, measuring and collecting the frictional resistance experienced by the welding wire at a set fixed position during the welding process includes the following steps:

[0018] An annular force sensor is installed upstream of the wire feed wheel to measure the frictional resistance experienced by the welding wire as it passes through the set position of the annular force sensor.

[0019] In some implementations, an annular force sensor can be installed upstream of the wire feed wheel to measure the change in frictional resistance experienced by the welding wire as it passes through a fixed position of the sensor, thereby qualitatively reflecting the fluctuations in axial wire feeding stability caused by changes in the welding wire's own state information.

[0020] Furthermore, in the method for evaluating the stability of welding wire feeding described in this invention, measuring the real-time coordinates of the center point of the welding wire on a set plane during the welding process includes the following steps:

[0021] A micrometer system is used to measure the real-time coordinates (x, y) of the center point of the welding wire on a set plane, where the welding start point is the origin of the coordinate system and the welding direction is the positive y-axis.

[0022] Furthermore, in the method for evaluating the stability of welding wire feeding described in this invention, the eccentricity D of the welding wire center point is obtained based on the real-time coordinates using the following formula:

[0023] D=(x 2 +|yv×t| 2 ) 1 / 2 ;

[0024] Where (x, y) represents the real-time coordinates of the welding wire center point, v is the welding speed (unit: mm / s), and t represents the welding time (unit: s).

[0025] In some implementations, the real-time coordinate data x and y of the center point of the welding wire on a plane of the welding wire extension can be measured by a high-precision micrometer system installed in the welding direction (the measurement coordinate system satisfies the right-hand rule, where the welding start point is the origin of the coordinate system and the welding direction is the positive y-axis). The change in the eccentricity D of the welding wire center relative to the welding gun center can then be calculated to measure the radial stability of the welding wire end.

[0026] Furthermore, in the method for evaluating the stability of welding wire feeding described in this invention, obtaining the azimuth angle θ (0°≤θ<360°) formed by the line connecting the welding wire center and the welding torch center and the positive welding direction based on the real-time coordinates includes the following steps: determining the azimuth angle θ based on the following formula:

[0027] θ = acrtan(x / (y-vt)) - 90°;

[0028] in:

[0029] When y-vt>0 and x≤0, 0°≤θ<90°;

[0030] When y-vt=0 and x<0, θ=90°;

[0031] When y-vt<0 and x≤0, 90°<θ≤180°;

[0032] When y-vt<0 and x>0, 180°<θ<270°;

[0033] When y-vt=0 and x>0, θ=270°;

[0034] When y-vt>0 and x>0, 270°<θ<360°;

[0035] Where (x, y) represents the real-time coordinates of the welding wire center point, v is the welding speed (unit: mm / s), and t represents the welding time (unit: s).

[0036] In some implementations, the real-time coordinate data x and y of the center point of the welding wire on a plane of the welding wire extension can be obtained online by installing a high-precision micrometer system in the welding direction. The angle θ between the line connecting the real-time center of the welding wire and the center of the welding gun (i.e., the theoretical center of the welding wire) and the positive welding direction can be calculated and used as the azimuth angle to reflect the spatial position change of the tip of the welding wire and measure the circumferential stability of the welding wire tip.

[0037] Furthermore, in the method for evaluating the welding wire feeding stability described in this invention, the evaluation of the wire feeding stability during the welding process, based on the changes in frictional resistance, eccentricity, and azimuth angle, includes the following steps:

[0038] The standard deviation of frictional resistance is obtained based on the change of frictional resistance, the standard deviation of eccentricity is obtained based on the change of eccentricity, and the standard deviation of azimuth is obtained based on the change of azimuth.

[0039] When the standard deviation of frictional resistance σ ≤ 0.5, the standard deviation of eccentricity σ ≤ 0.2, and the standard deviation of azimuth angle σ ≤ 5, the wire feeding stability of the welding wire is judged to be excellent.

[0040] Furthermore, in the method for evaluating the welding wire feeding stability described in this invention, the evaluation of the wire feeding stability during the welding process, based on the changes in frictional resistance, eccentricity, and azimuth angle, includes the following steps:

[0041] The standard deviation of frictional resistance is obtained based on the change of frictional resistance, the standard deviation of eccentricity is obtained based on the change of eccentricity, and the standard deviation of azimuth is obtained based on the change of azimuth.

[0042] The wire feeding stability of the welding wire is deemed good when at least one of the following conditions is met:

[0043] The standard deviation of frictional resistance is 0.5 < σ ≤ 3;

[0044] The standard deviation of eccentricity is 0.2 < σ ≤ 0.5;

[0045] The standard deviation of the azimuth angle is 5 ≤ ​​σ ≤ 10.

[0046] Furthermore, in the method for evaluating the welding wire feeding stability described in this invention, the evaluation of the wire feeding stability during the welding process, based on the changes in frictional resistance, eccentricity, and azimuth angle, includes the following steps:

[0047] The standard deviation of frictional resistance is obtained based on the change of frictional resistance, the standard deviation of eccentricity is obtained based on the change of eccentricity, and the standard deviation of azimuth is obtained based on the change of azimuth.

[0048] The wire feeding stability is deemed poor when at least one of the following conditions is met:

[0049] The standard deviation of frictional resistance σ > 3;

[0050] The standard deviation of eccentricity σ > 0.5;

[0051] The standard deviation of the azimuth angle σ > 10.

[0052] The method for evaluating welding wire feeding stability described in this invention has the following advantages and beneficial effects compared to the prior art:

[0053] The evaluation method described in this invention can evaluate the feeding stability of the welding wire during the welding process using three indicators: frictional resistance (axial), eccentricity (radial), and azimuth angle (circumferential). Compared with existing technologies, it not only improves the detection of axial feeding stability but also supplements the evaluation techniques for the spatial position of the welding wire end, making the evaluation method more comprehensive and accurate.

[0054] Furthermore, the evaluation method described in this invention requires simple equipment that is easy to install and operate, and has high scalability. Attached Figure Description

[0055] Figure 1 The schematic diagram shows the structural structure of the implementation system of the welding wire feeding stability evaluation method of the present invention.

[0056] Figure 2 The results of the frictional resistance change detection are shown in Example 1 of the evaluation method for welding wire feeding stability described in this invention.

[0057] Figure 3 The results of eccentricity variation detection are shown in Example 1 of the evaluation method for welding wire feeding stability described in this invention.

[0058] Figure 4 The results of azimuth angle variation detection are shown for Example 1, which uses the evaluation method for welding wire feeding stability described in this invention.

[0059] Figure 5 The results of the frictional resistance change detection are shown in Example 2 of the evaluation method for welding wire feeding stability described in this invention.

[0060] Figure 6 The results of the detection of eccentricity and changes in Example 2 of the evaluation method for welding wire feeding stability described in this invention are shown.

[0061] Figure 7 The results of azimuth angle change detection are shown in Example 2 of the evaluation method for welding wire feeding stability described in this invention.

[0062] Figure 8 The results of the frictional resistance change detection are shown in Example 3 of the evaluation method for welding wire feeding stability described in this invention.

[0063] Figure 9 The results of eccentricity variation detection are shown in Example 3 of the evaluation method for welding wire feeding stability described in this invention.

[0064] Figure 10 The results of azimuth angle change detection are shown in Example 3 of the evaluation method for welding wire feeding stability described in this invention. Detailed Implementation

[0065] The evaluation method for welding wire feeding stability described in this invention will be further explained and described below with reference to specific embodiments and accompanying drawings. However, this explanation and description do not constitute an undue limitation on the technical solution of this invention.

[0066] Figure 1 The schematic diagram shows the structural structure of the implementation system of the welding wire feeding stability evaluation method of the present invention.

[0067] like Figure 1 As shown, in some embodiments, the evaluation method described in this invention can be implemented using this implementation system, which includes: a welding torch 1 for welding, a wire feeding wheel and a clamping wheel 2 for feeding welding wire 3, the front end of welding wire 3 being a welding wire extension 4, the welding torch 1 welding a welding test plate 6 placed on a welding platform 7 to obtain a weld pool 5, the welding torch 1 being connected to a welding power source 8, an annular force sensor 9 being sleeved around the welding wire and positioned upstream of the wire feeding wheel, a micrometer system including a laser generator 10, a micrometer laser receiver 11, an optical filter system 12, a micrometer optical path 13, and a signal acquisition and recording system 14, which acquires data sent to it by the micrometer laser receiver 11 and the annular force sensor 9, and sends this data to a computer 15 for analysis and processing.

[0068] In some implementations, the method for evaluating the stability of welding wire feeding may include the steps of:

[0069] 100: A ring force sensor 9 is used to measure the frictional resistance of the welding wire 3 at a set position during the welding process, and a signal acquisition and recording system 14 is used to collect the changes in the frictional resistance of the welding wire at the set position during the welding process and send them to a computer 15.

[0070] By installing a ring-shaped force sensor upstream of the wire feed wheel, the change in frictional resistance experienced by the welding wire as it passes through the fixed position of the sensor is measured, so as to qualitatively reflect the fluctuation of axial wire feeding stability caused by the change in the state information of the welding wire itself.

[0071] 200: A micrometer system is used to measure the real-time coordinates (x, y) of the center point of the welding wire on a set plane during the welding process, where the welding start point is the origin and the welding direction is the positive y-axis. The real-time coordinate data shows that x is perpendicular to the welding direction and y is parallel to the welding direction.

[0072] 300: The eccentricity D of the welding wire center point and the change of the eccentricity are obtained based on the real-time coordinates (x, y);

[0073] In some more specific implementations, the eccentricity D of the welding wire center point can be obtained using the following formula:

[0074] D=(x 2 +|yv×t| 2 ) 1 / 2 .

[0075] In this embodiment, the real-time coordinate data x and y of the center point of the welding wire on a plane of the welding wire extension are measured by a high-precision micrometer system installed in the welding direction (the measurement coordinate system satisfies the right-hand rule, where the welding start point is the origin of the coordinate system and the welding direction is the positive y-axis). The change in the eccentricity D of the welding wire center relative to the welding gun center is calculated to measure the radial stability of the welding wire end.

[0076] 400: Based on real-time coordinates (x, y), the azimuth angle formed by the line connecting the welding wire center and the welding gun center and the positive welding direction, as well as the change of the azimuth angle, are obtained;

[0077] In some more specific implementations, the azimuth angle θ (0°≤θ﹤360°) formed by the line connecting the center of the welding wire and the center of the welding torch and the positive welding direction can be obtained using the following formula:

[0078] θ=acrtan(x / (y-vt))-90°; where:

[0079] When y-vt>0 and x≤0, 0°≤θ<90°;

[0080] When y-vt=0 and x<0, θ=90°;

[0081] When y-vt<0 and x≤0, 90°<θ≤180°;

[0082] When y-vt<0 and x>0, 180°<θ<270°;

[0083] When y-vt=0 and x>0, θ=270°;

[0084] When y-vt>0 and x>0, 270°<θ<360°.

[0085] By installing a high-precision micrometer system in the welding direction, the real-time coordinate data x and y of the center point of the welding wire on a certain plane of the welding wire extension are obtained online. The angle θ between the line connecting the real-time center of the welding wire and the center of the welding gun (i.e., the theoretical center of the welding wire) and the positive welding direction is calculated and used as the azimuth angle. It can reflect the spatial position change of the tip of the welding wire and measure the circumferential stability of the welding wire tip.

[0086] 500: The wire feeding stability during the welding process is evaluated based on the changes in frictional resistance, eccentricity, and azimuth angle.

[0087] In some more specific implementations, the wire feeding stability is considered excellent when the standard deviation of frictional resistance σ ≤ 0.5, the standard deviation of eccentricity σ ≤ 0.2, and the standard deviation of azimuth angle σ ≤ 5.

[0088] The wire feeding stability of the welding wire is deemed good when at least one of the following conditions is met:

[0089] The standard deviation of frictional resistance is 0.5 < σ ≤ 3;

[0090] The standard deviation of eccentricity is 0.2 < σ ≤ 0.5;

[0091] The standard deviation of the azimuth angle is 5 ≤ ​​σ ≤ 10.

[0092] The wire feeding stability is deemed poor when at least one of the following conditions is met:

[0093] The standard deviation of frictional resistance σ > 3;

[0094] The standard deviation of eccentricity σ > 0.5;

[0095] The standard deviation of the azimuth angle σ > 10.

[0096] The standard deviation σ is calculated using the following formula:

[0097]

[0098] Where σ represents the standard deviation of the data for frictional resistance, eccentricity, and azimuth angle, x i This represents the real-time data of frictional resistance, eccentricity, and azimuth angle collected during the sampling period, where n represents the total number of data collected. This represents the average value of all collected data on frictional resistance, eccentricity, and azimuth, where i is an integer from 1 to n.

[0099] To further demonstrate the technical effects of the preferred embodiment of this invention, the present invention uses the same submerged arc welding machine and selects three welding wires (i.e., Example 1, Example 2, and Example 3) with the same strength level but different compositions for flat plate surfacing to compare their wire feeding stability.

[0100] In Examples 1-3, the length of the welding test plate 6 in the welding direction can be 160mm, the diameter of the welding wire 3 is controlled at 4mm, and the length of the welding wire extension 4 can be controlled at 15mm. Furthermore, the welding parameters for the three types of welding wire are the same during welding: the welding current can be controlled at 500A, the welding voltage at 28V, the welding speed at 480mm / min, and the shielding gas flow rate at 20L / min.

[0101] In Examples 1-3, such as Figure 1As shown, a micrometer laser generator 10, a micrometer laser receiver 11, a signal acquisition and recording system 14, and a computer 15 can be arranged perpendicular to the plane of the welding wire extension. The measurement direction of the micrometer system is consistent with the welding direction, and the measurement center is consistent with the weld center. The micrometer laser generator 10 and the micrometer laser receiver 11 are fixed to the head and tail of the welding test plate 6, respectively, so that the length of the micrometer optical path 13 is consistent with the welding length. More specifically, the sampling frequency of the micrometer laser receiver 11 can be controlled to 100 Hz, and the optical filter system 12 can use a neutral density filter with 50% transmittance.

[0102] After calibrating the micrometer system and turning on the signal acquisition and recording system 14, flat plate welding experiments can be started on the three types of welding wires (i.e., Example 1, Example 2, and Example 3). Furthermore, the detection time (i.e., welding duration) can be controlled to 20 seconds to obtain the frictional resistance and real-time coordinate data (x, y) of the welding wire center. The computer 15 processes and converts this data to obtain the change in the eccentricity between the welding wire center and the welding torch center (i.e., the eccentricity spectrum), as well as the change in the azimuth angle θ between the line connecting the welding wire center and the welding torch center and the positive welding direction.

[0103] Figure 2 , Figure 3 and Figure 4 The graph shows the detection results for frictional resistance, eccentricity, and azimuth angle changes in Example 1. The horizontal axis represents the detection time, i.e., the entire welding process; the vertical axis represents... Figures 2-4 The numbers represent frictional resistance, eccentricity, and azimuth, respectively.

[0104] from Figure 2 , Figure 3 and Figure 4 As can be seen from the data, in Example 1, the frictional resistance, eccentricity, and azimuth angle fluctuated greatly during the welding process, with standard deviations of 3.3, 0.6, and 10.2, respectively. According to the judgment and evaluation index of the present invention, its wire feeding stability was judged to be poor.

[0105] Figure 5 , Figure 6 and Figure 7 The graph shows the detection results for frictional resistance, eccentricity, and azimuth angle changes in Example 2. The horizontal axis represents the detection time, i.e., the entire welding process; the vertical axis represents... Figures 5-7 The numbers represent frictional resistance, eccentricity, and azimuth, respectively.

[0106] from Figure 5 , Figure 6 and Figure 7 As can be seen from the data, in Example 2, the standard deviations of frictional resistance, eccentricity, and azimuth angle during the welding process are 1.4, 0.4, and 3.9, respectively. According to the judgment and evaluation index of the present invention, its wire feeding stability is judged to be good.

[0107] Figure 8 , Figure 9 and Figure 10 The figures show the detection results for frictional resistance, eccentricity, and azimuth angle changes in Example 3. The horizontal axis represents the detection time, i.e., the entire welding process; the vertical axis represents... Figures 8-10 The numbers represent frictional resistance, eccentricity, and azimuth, respectively.

[0108] from Figure 8 , Figure 9 and Figure 10 As can be seen from the data, in Example 3, the frictional resistance, eccentricity, and azimuth angle change very little during the welding process, with standard deviations of 0.3, 0.1, and 1.8, respectively. According to the judgment and evaluation index of the present invention, its wire feeding stability is judged to be excellent.

[0109] It should be noted that the combination of the technical features in this case is not limited to the combination methods described in the claims of this case or the combination methods described in the specific embodiments. All technical features described in this case can be freely combined or combined in any way, unless they contradict each other.

[0110] It should also be noted that the embodiments listed above are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made thereto are those that can be directly derived or easily conceived by those skilled in the art from the content disclosed in the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A method for evaluating the stability of welding wire feeding, characterized in that, Including the following steps: The frictional resistance experienced by the welding wire at a set position during the welding process was measured, and the changes in the frictional resistance experienced by the welding wire at the set position during the welding process were collected. Measure the real-time coordinates of the center point of the welding wire on a set plane during the welding process; The eccentricity of the welding wire center point and the change of the eccentricity are obtained based on the real-time coordinates. Based on the real-time coordinates, the azimuth angle formed by the line connecting the center of the welding wire and the center of the welding gun and the positive welding direction, as well as the change of the azimuth angle, are obtained. The wire feeding stability during the welding process is evaluated based on the changes in frictional resistance, eccentricity, and azimuth angle.

2. The method for evaluating the stability of welding wire feeding as described in claim 1, characterized in that, Measuring and collecting the frictional resistance experienced by the welding wire at a predetermined fixed position during the welding process includes the following steps: An annular force sensor is installed upstream of the wire feed wheel to measure the frictional resistance experienced by the welding wire as it passes through the set position of the annular force sensor.

3. The method for evaluating the stability of welding wire feeding as described in claim 1, characterized in that, Measuring the real-time coordinates of the center point of the welding wire on a set plane during welding includes the following steps: A micrometer system is used to measure the real-time coordinates (x, y) of the center point of the welding wire on a set plane, where the welding start point is the origin of the coordinate system and the welding direction is the positive y-axis.

4. The method for evaluating the stability of welding wire feeding as described in claim 1, characterized in that, Based on the real-time coordinates, the eccentricity D of the welding wire center point is obtained using the following formula: D=(x 2 +|y-v×t| 2 ) 1 / 2 ; Where (x, y) represents the real-time coordinates of the welding wire center point, v is the welding speed (unit: mm / s), and t represents the welding time (unit: s).

5. The method for evaluating the stability of welding wire feeding as described in claim 1, characterized in that, The steps to obtain the azimuth angle θ formed by the line connecting the center of the welding wire and the center of the welding torch and the positive welding direction based on the real-time coordinates include: determining the azimuth angle θ based on the following formula: θ=acrtan(x / (y-vt))-90°; where: When y-vt>0 and x≤0, 0°≤θ<90°; When y-vt=0 and x<0, θ=90°; When y-vt<0 and x≤0, 90°<θ≤180°; When y-vt<0 and x>0, 180°<θ<270°; When y-vt=0 and x>0, θ=270°; When y-vt>0 and x>0, 270°<θ<360°; Where (x, y) represents the real-time coordinates of the welding wire center point, v is the welding speed (unit: mm / s), and t represents the welding time (unit: s).

6. The method for evaluating the stability of welding wire feeding as described in claim 1, characterized in that, The evaluation of wire feeding stability during welding, based on the changes in frictional resistance, eccentricity, and azimuth angle, includes the following steps: The standard deviation of frictional resistance is obtained based on the change of frictional resistance, the standard deviation of eccentricity is obtained based on the change of eccentricity, and the standard deviation of azimuth is obtained based on the change of azimuth. When the standard deviation of frictional resistance σ ≤ 0.5, the standard deviation of eccentricity σ ≤ 0.2, and the standard deviation of azimuth angle σ ≤ 5, the wire feeding stability of the welding wire is judged to be excellent.

7. The method for evaluating the stability of welding wire feeding as described in claim 1, characterized in that, The evaluation of wire feeding stability during welding, based on the changes in frictional resistance, eccentricity, and azimuth angle, includes the following steps: The standard deviation of frictional resistance is obtained based on the change of frictional resistance, the standard deviation of eccentricity is obtained based on the change of eccentricity, and the standard deviation of azimuth is obtained based on the change of azimuth. The wire feeding stability of the welding wire is deemed good when at least one of the following conditions is met: The standard deviation of frictional resistance is 0.5 < σ ≤ 3; The standard deviation of eccentricity is 0.2 < σ ≤ 0.5; The standard deviation of the azimuth angle is 5 ≤ ​​σ ≤ 10.

8. The method for evaluating the stability of welding wire feeding as described in claim 1, characterized in that, The evaluation of wire feeding stability during welding, based on the changes in frictional resistance, eccentricity, and azimuth angle, includes the following steps: The standard deviation of frictional resistance is obtained based on the change of frictional resistance, the standard deviation of eccentricity is obtained based on the change of eccentricity, and the standard deviation of azimuth is obtained based on the change of azimuth. The wire feeding stability is deemed poor when at least one of the following conditions is met: The standard deviation of frictional resistance σ > 3; The standard deviation of eccentricity σ > 0.5; The standard deviation of the azimuth angle σ > 10.

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