Method for determining connection quality

Abstract

The invention relates to a method for determining the quality of a connection (1), in particular for determining a characteristic value representative of the quality of a connection (1) of an electrically conductive element (2), in which first a plurality of eddy current measurements are carried out at predetermined positions (11, 11 ') of the connection (1) by means of an eddy current measuring device (3), the amplitude and phase angle of the eddy current are then captured at each predetermined position (11, 11 ') of the connection (1) by means of an eddy current measuring device (3). Subsequently, tensors and / or matrices are determined by means of an evaluation unit / control device (4) as a function of the captured amplitudes and phase angles. The quality of the connection (1) is then determined by the evaluation unit (4) at least by means of the characteristic value on the basis of the determined tensor and / or matrix.

Description

[0001] manual:

[0002] The invention relates to a method for determining the quality of a connection, in particular for determining a characteristic value representing the quality of a connection of an electrically conducting element.

[0003] Eddy current measurements are currently used, for example, for the final testing of ultrasonic welds. However, not all poor connections or defects can be detected with eddy current measurements, as the measurement only covers one layer of the weld. If the density of this layer is sufficient, the weld is rated as "good," even though other areas may be insufficiently welded.

[0004] Welded joints, especially damaged ones, consist of regions of varying density. Therefore, damaged joint regions may also have high density, especially when the joint still maintains its structural integrity.

[0005] This results in eddy current measurements delivering results close to good values. Differences in material quality, such as the dispersion of the base material, and varying welding parameters, such as those caused by adjustments at the start of a shift, can lead to additional dispersion in the eddy current measurement results. Consequently, only slightly damaged contacts can be difficult to identify, resulting in gray areas.

[0006] Furthermore, weld quality inspection can only be performed destructively. This is problematic, however, because the product cannot be sold after this inspection. Consequently, not all ultrasonic welded connections produced are inspected, and there is always the risk of delivering defective welds.

[0007] It is therefore an object of the present invention to provide a method for determining the quality of a connection, which method enables non-destructive testing of the connection and the identification of defects in the connection, in particular during final testing.

[0008] This object is achieved by the combination of features according to patent claim 1 .

[0009] The basic idea of ​​the present invention is to evaluate and treat the joint as a three-dimensional object with varying structures (e.g., strength) to improve the detection rate of weld defects. Eddy current measurements are intended to generate a three-dimensional record of the weld joint. The recorded amplitude and phase values ​​enable evaluation of the weld joint. The 3D scan allows for the identification of areas of varying density, thus reliably identifying defective areas. However, variations are also contemplated in which two-dimensional or one-dimensional measurements are used to determine characteristic values.

[0010] According to the present invention, a method for determining the quality of a connection, in particular for determining characteristic values ​​representing the quality of a connection of electrically conductive elements, is provided. The method first involves performing a plurality of eddy current measurements at predetermined locations on the connection using an eddy current measuring device. The eddy current amplitudes and phase angles are then captured at each predetermined location on the connection using the eddy current measuring device. Subsequently, a tensor and / or matrix is ​​determined from the captured amplitudes and phase angles using an evaluation unit. The quality of the connection is then determined by the evaluation unit based on the determined tensor and / or matrix, at least using the characteristic values.

[0011] Within the scope of the present invention, an evaluation unit also refers to a control device or a corresponding component for data processing and / or controlling electrically controllable components. Examples of eddy current measuring devices include fluxgate magnetometers or Foster probes. Furthermore, the method is also suitable for determining ultrasonic welding parameters and / or verifying connections, for example.

[0012] In a preferred embodiment, the connection is an ultrasonic welded connection. Furthermore, in the method, the quality of the ultrasonic welded connection is determined, in particular for determining a characteristic value representative of the quality of the ultrasonic welded connection of the electrically conductive element.

[0013] In a preferred embodiment of the present invention, the eddy current measuring device includes a sensor array for eddy current measurement and / or a manipulation device for variably positioning the eddy current measuring device, thereby enabling multiple eddy current measurements to be performed at different locations along the connection. When eddy current measurements are performed using the sensor array, multiple eddy current measurements are performed by a single sensor of the sensor array located at a predetermined position, or when eddy current measurements are performed using the manipulation device, multiple eddy current measurements are performed by eddy current measuring devices positioned at different positions. However, it is also contemplated that the sensor array may be positioned adjacent to the manipulation device, which is designed for variably positioning the sensor array. This improves the accuracy of the eddy current measurements.

[0014] In an advantageous embodiment, the eddy current measurement is performed along the connected predetermined xyz coordinate system in depth (z). This has the advantage that, due to the predetermined xyz coordinate system, the measurement is reproducible and can be compared with target values ​​or other eddy current measurements.

[0015] Furthermore, an embodiment is preferred in which the eddy current measurement is performed along the xy plane of an xyz coordinate system, wherein the sensor array is arranged along the xy plane. In a further embodiment of the method, the sensor array of the eddy current measuring device is operated at a predetermined cycle. The sensors of the sensor array perform eddy current measurements intermittently, for example, individually, in pairs, or with a predetermined number of other sensors in the sensor array.

[0016] In an alternative embodiment of the method, the eddy current measurement is performed along the xy plane of the xyz coordinate system, wherein the eddy current measuring device is arranged at multiple positions along the xy plane by means of a manipulator. Thus, the eddy current measurement of this variant can be performed at all predetermined positions.

[0017] In an advantageous embodiment variant, it is provided that the xy plane of the predetermined xyz coordinate system is defined along the weld seam and / or parallel to the weld plane. In this way, the execution and evaluation of the eddy current measurement is optimized.

[0018] In one embodiment of the method, eddy current measurements are performed in the depth (z) direction of the connected xyz coordinate system. To this end, the frequency of the eddy current measuring device is varied in a position-dependent manner, and measurements are performed at predetermined frequencies. Alternatively, eddy current measurements are performed at a plurality of predetermined positions along the depth (z) direction of the connected xyz coordinate system. Furthermore, the eddy current measurements are performed using a noise signal from the eddy current measuring device that includes all frequencies. In this way, measurements can be performed at different predetermined positions in the z direction or along the depth (z) of the connection.

[0019] In another embodiment of the method, according to the present invention, when determining the at least one characteristic value representing the connection quality, the evaluation unit determines the at least one characteristic value using a learnable algorithm and / or at least one other mathematical method. This allows for optimal analysis or evaluation of the determined tensors and / or matrices. Furthermore, it is advantageous if the at least one other mathematical method is a standard deviation, mean value, maximum value, chi-square test, and / or dispersion.

[0020] In a preferred embodiment of the method, the at least one characteristic value is the pull-off force and / or the shear force of the connection. These characteristic values ​​are particularly suitable for evaluating the connection.

[0021] In an embodiment of the method, at least one further eddy current measuring device is also provided, which is arranged radially spaced apart from the eddy current measuring device relative to the connection, thereby further increasing the accuracy of the eddy current measurement.

[0022] In another advantageous variant, the invention provides that the at least one additional eddy current measuring device is arranged such that the magnetic fields generated by the eddy current measuring devices extend relative to one another. Furthermore, in one embodiment, the respective eddy current measuring devices are arranged such that the generated magnetic fields are incident on the connection at an angle. By generating a magnetic field that is not perpendicular to the connection in this way, the sensitivity of the eddy current measurement is further increased.

[0023] As long as it is technically feasible and not contradictory, the above features can be combined as needed.

[0024] Other advantageous further developments of the present invention are described in the dependent claims or are described in detail below together with the description of preferred embodiments of the present invention with reference to the accompanying drawings.

[0025] Figure 1 A schematic diagram showing an apparatus for determining the quality of an ultrasonic welded connection;

[0026] Figure 2 A schematic flow chart showing a method for determining the quality of an ultrasonic welded connection using the device is shown.

[0027] The accompanying drawings are schematic examples. The same reference numerals in the accompanying drawings represent the same functions and / or structural features.

[0028] Figure 1 A schematic diagram of an apparatus for determining the quality of an ultrasonic welded connection 1 is shown. The apparatus first comprises an eddy current measuring device 3 for performing a plurality of eddy current measurements at predetermined locations 11, 11' of the connection 1 and capturing the amplitude and phase angle of the eddy currents at each predetermined location 11, 11' of the connection 1. Furthermore, a further eddy current measuring device 3' is provided, which is arranged radially spaced apart from the eddy current measuring device 3 relative to the connection 1. The at least one further eddy current measuring device 3' is arranged such that the magnetic fields generated by the eddy current measuring devices 3, 3' extend relative to one another. Furthermore, the respective eddy current measuring devices 3, 3' are arranged such that the generated magnetic fields are incident obliquely on the connection 1.

[0029] Furthermore, the device comprises an evaluation unit 4 for determining a tensor and / or a matrix from the captured amplitudes and phase angles, and for determining the quality of the ultrasonic welded joint 1 based on the determined tensor and / or matrix at least by means of eigenvalues. When determining the at least one eigenvalue representative of the quality of the joint 1, the at least one eigenvalue can be determined by the evaluation unit 4 by means of a learnable algorithm and / or at least one other mathematical method.

[0030] in addition, Figure 1 The device shown comprises an operating device 32 for displaceably arranging the corresponding eddy current measuring devices 3 , 3 ′ so as to perform a plurality of eddy current measurements at different positions of the ultrasonic welded joint 1 .

[0031] Figure 2 A schematic flow chart of a method for determining the quality of an ultrasonic welded connection 1 using the above-described device is shown.

[0032] In a method for determining the quality of an ultrasonically welded connection 1, in particular for determining a characteristic value representative of the quality of an ultrasonically welded connection 1 of an electrically conductive element 2, a plurality of eddy current measurements are first performed (step a) at predetermined locations 11, 11' of the connection 1 using an eddy current measuring device 3 and a further eddy current measuring device 3', the further eddy current measuring device being arranged radially spaced apart from the eddy current measuring device 3 relative to the connection 1. The further eddy current measuring device 3' is arranged such that the magnetic fields generated by the eddy current measuring devices 3, 3' extend relative to each other. Furthermore, the respective eddy current measuring devices 3, 3' are arranged such that the generated magnetic fields are incident obliquely on the connection 1.

[0033] Each eddy current measuring device 3 , 3 ′ includes a sensor array 31 for eddy current measurement and / or a manipulation device 32 for displaceably arranging the eddy current measuring device 3 , so that multiple eddy current measurements can be performed at different positions of the ultrasonic welded joint 1 .

[0034] Furthermore, eddy current measurements are performed along a predetermined xyz coordinate system of the joint 1 at a depth z. The xy plane of the predetermined xyz coordinate system is defined along the weld seam and / or parallel to the weld plane. Furthermore, the manipulator 32 positions the eddy current measuring device 3 at a plurality of positions 11, 11' along the xy plane.

[0035] Alternatively, the sensor array 31 of the eddy current measuring device 3 is arranged along the xy plane and operates at a predetermined clock rate.

[0036] Alternatively, eddy current measurements are performed in the depth (z) direction of the xyz coordinate system of the connection 1. To this end, the frequency of the eddy current measuring device 3 is varied in a position-dependent manner, and measurements are performed at predetermined frequencies. Alternatively, eddy current measurements are performed at a plurality of predetermined positions 11, 11' along the depth (z) direction of the xyz coordinate system of the connection 1 using a noise signal from the eddy current measuring device 3 containing all frequencies.

[0037] Next, the amplitude and phase angle of the eddy currents are captured at respective predetermined locations 11 , 11 ′ of the connection 1 by means of the eddy current measuring device 3 (step b).

[0038] Subsequently, with the aid of the evaluation unit 4 , a tensor and / or matrix is ​​determined from the captured amplitudes and phase angles (step c).

[0039] The quality of the ultrasonic welded joint 1 is then determined by the evaluation unit 4 based on the determined tensor and / or matrix, at least with the aid of the eigenvalues ​​(step d). When determining the at least one eigenvalue representing the quality of the joint 1, the evaluation unit 4 uses a learnable algorithm and / or at least one other mathematical method to determine the at least one eigenvalue. The at least one other mathematical method is a standard deviation, a mean value, a maximum value, a chi-square test, and / or a dispersion. The at least one eigenvalue is the pull-off force and / or the shear force of the ultrasonic welded joint 1.

[0040] The present invention is not limited to the preferred embodiments described above in its implementation. In fact, many variants can be envisaged, which can use the above-described solutions even in different embodiments of the basic design.

Claims

1. A method for determining the quality of a connection (1), in particular for determining a characteristic value representing the quality of a connection (1) of an electrically conductive element (2), comprising the following steps: a. performing multiple eddy current measurements at predetermined positions (11, 11') of the connection (1) by means of an eddy current measuring device (3), b. capturing the amplitude and phase angle of the eddy currents at various predetermined positions (11, 11') of the connection (1) by means of the eddy current measuring device (3), c. determining a tensor and / or matrix from the captured amplitudes and phase angles by means of an evaluation unit (4), d. Determining the quality of the connection (1) by the evaluation unit (4) based on the determined tensors and / or matrices at least with the aid of eigenvalues.

2. The method according to claim 1, wherein The connection (1) is an ultrasonic welded connection, wherein the quality of the ultrasonic welded connection is determined, in particular for determining a characteristic value representative of the quality of the ultrasonic welded connection (1) of the electrically conducting element (2).

3. The method according to claim 1 or 2, wherein: The eddy current measuring device (3) comprises a sensor array (31) for eddy current measurement and / or a manipulation device (32) for displacing the eddy current measuring device (3), thereby performing multiple eddy current measurements at different positions of the connection (1).

4. The method according to any one of claims 1 to 3, wherein The eddy current measurements are performed at depth (z) along a predetermined xyz coordinate system of the connection (1).

5. The method according to claim 4, wherein The eddy current measurement is performed along the xy plane of the xyz coordinate system, wherein the sensor array (31) is arranged along the xy plane.

6. The method according to claim 5, wherein: The sensor array (31) of the eddy current measuring device (3) operates at a predetermined clock rate.

7. The method according to claim 4, wherein: The eddy current measurement is performed along the xy plane of the xyz coordinate system, wherein the eddy current measuring device (3) is arranged at a plurality of positions (11, 11') along the xy plane by means of the manipulator (32).

8. The method according to any one of claims 4 to 7, wherein The predetermined xyz coordinate system and the xy plane are determined along the weld seam and / or parallel to the weld plane.

9. The method according to any one of claims 4 to 8, wherein The eddy current measurements are respectively performed in the depth (z) direction of the xyz coordinate system of the connection (1), wherein for this purpose the frequency of the eddy current measuring device (3) is varied, in particular in a position-dependent manner, and the measurement is performed at a predetermined frequency.

10. The method according to any one of claims 4 to 8, wherein The eddy current measurement is performed at a plurality of predetermined positions (11, 11') in the depth (z) direction of the xyz coordinate system of the connection (1), wherein the eddy current measurement is also performed by a noise signal of the eddy current measuring device (3) containing all frequencies.

11. A method according to any preceding claim, wherein: When determining at least one characteristic value representing the quality of the connection (1), the evaluation unit (4) determines the at least one characteristic value by means of a learnable algorithm and / or at least one other mathematical method.

12. The method according to claim 11, wherein The at least one other mathematical method is standard deviation, mean, maximum value, chi-square test and / or dispersion.

13. A method according to any preceding claim, wherein: The at least one characteristic value is the pull-off force and / or the shear force of the connection (1).

14. A method according to any preceding claim, wherein: At least one further eddy current measuring device (3') is also provided, which is arranged radially spaced apart from the eddy current measuring device (3) relative to the connection (1).

15. The method according to claim 14, wherein: The at least one further eddy current measuring device (3') is arranged such that the magnetic fields generated by the eddy current measuring devices (3, 3') extend towards each other.

16. A method according to any preceding claim, wherein: The corresponding eddy current measuring device (3, 3') is arranged such that the generated magnetic field is incident obliquely on the connection (1).

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