CN112074371B

CN112074371B - Method for monitoring a joining process

Info

Publication number: CN112074371B
Application number: CN201980028049.9A
Authority: CN
Inventors: I·埃珀莱因
Original assignee: Klonberg And Schubert Motor Co ltd
Current assignee: Klonberg And Schubert Motor Co ltd
Priority date: 2018-10-25
Filing date: 2019-10-18
Publication date: 2021-07-06
Anticipated expiration: 2039-10-18
Also published as: DE102018126697B4; WO2020083774A1; EP3752318A1; DE102018126697A1; CN112074371A

Abstract

The invention relates to a method for monitoring a joining process on a joining tool for joining at least two joining bodies (10, 20) to form a composite body (30), wherein at least one joining body is a strand, a camera (50) is provided, by means of which at least a part of the joining tool is optically detected and the tool properties of the joining tool are optically detected by means of the camera (50) before joining the joining bodies (10, 20) and determined from the optical detection, wherein at least one joining body (10, 20) is optically detected by means of the camera (50) before joining the joining bodies (10, 20) and the detected joining body properties of the joining body (10, 20) are determined, and the composite body (30) is optically detected by means of the camera (50) and the composite body properties are determined during and/or after joining the joining bodies (10, 20) to form the composite body (30), correction parameters for correcting the joining process and/or quality characteristics for determining the quality of the joining process and the composite (30) are determined from the tool characteristics, the joining body characteristics and the composite characteristics.

Description

Method for monitoring a joining process

Technical Field

The invention relates to a method for monitoring a joining process on a joining tool for joining at least two joining bodies to form a composite body, wherein at least one joining body is a strand.

Background

A number of different process monitoring methods are known in the art. In the production of composite bodies, the quality or quality features of the connecting elements of the connecting body are usually controlled only after the actual joining process, depending on the individual inspection stations provided for this purpose. In the case of inadequate quality, the connecting body is selected from the corresponding production process, so that no improvement in the joining process or in the subsequent composite body is possible.

If, in addition to the quality of the joining process, other process parameters are to be controlled, separate inspection or measuring stations are usually provided in the prior art for this purpose, so that the devices required for the inspection are present several times and/or are also spatially separated.

The devices for carrying out and quality control of such joining processes are expensive to purchase due to the devices required several times, and the inspection and measurement data acquired for this are often irrelevant, since it is generally not necessary to draw conclusions about the quality-controlled measurement data and the measurement data of the measurement devices used to acquire the process variables during the joining process for the process parameters of a particular joining process.

Disclosure of Invention

It is therefore an object of the present invention to overcome the aforementioned disadvantages and to provide a method by means of which process parameters of a joining process can be acquired and monitored at least partially before the joining process, so that the quality of a subsequent joining connection can be checked at the same time and the joining process can be improved for a subsequent joining connection produced by the joining method.

This object is achieved by the combination of features according to claim 1.

According to the invention, a method for monitoring a joining process on a joining tool for joining at least two joining bodies to form a composite body is proposed. By means of this joining process, an electrically conductive connection is established in particular between the joining bodies. For at least two of the bonded bodies, one of the bonded bodies is a stranded wire. A joining tool for producing a connection between joining bodies or for producing a composite body from the joining bodies comprises a support surface for supporting one of the joining bodies, at least one clamping element for temporarily securing the joining bodies to one another during a joining process, and a tool head for continuously joining the joining bodies to form the composite body. At least one camera or preferably exactly one camera is also provided for the method, by means of which at least a part of the joining tool is optically captured. The joining tool is optically captured by a camera before joining the joined bodies and tool characteristics of the joining tool are determined from the optical capture. Furthermore, at least one of the bonded bodies is optically captured by a camera before bonding the bonded bodies and the bonded body characteristics of the captured bonded body are determined. The complex is also optically captured by a camera and the properties of the complex are determined during and/or after the joining of the bonded bodies to the complex. Before, during and/or after the joining process, correction parameters for correcting the joining process and/or quality characteristics for determining the quality of the joining process and the composite are determined from the tool characteristics, the joining body characteristics and the composite characteristics determined therefrom. If the determined characteristic deviates from the theoretical characteristic and the characteristic cannot be corrected, the joining process can be completely eliminated.

During the joining process, the joining tool is first calibrated for the joining, wherein the movable elements, for example the at least one clamping element and the tool head, are moved in the process towards the initial position. Before the joining body is arranged on the support surface, the joining tool and in particular the support surface, which has not yet been joined to it, is optically captured by a camera to generate tool properties. In this case, it is also possible to obtain by means of the camera whether the movable element is located in its predetermined initial position and whether the joining tool is calibrated or ready for the joining process.

The joining bodies are then arranged simultaneously or successively in the joining tool and in particular on the support surface, wherein the joining bodies are acquired individually or jointly by the camera during or after the arrangement on the support surface in order to derive the joining body properties. During or after the assembly of the assembly, the at least one clamping element is moved from its initial position into a clamping position and clamps the assembly firmly on the support surface, so that the assembly is temporarily fastened to the support surface for the purpose of joining and is subsequently fastened. In this case, the properties of the joining body and whether the joining body is clamped or fastened on the support surface can be determined by acquiring the properties of the joining body with a camera before or after clamping.

The composite properties of the composite body can be obtained after or during joining of the joined bodies into the composite body without loosening the clamping.

Furthermore, in order to improve the optical acquisition by the camera, a light source can be provided in the method, which light source illuminates the area optically acquired by the camera, so that a uniform light proportion is preferably established which remains constant during the optical acquisition by the camera.

An advantageous development of the method consists in that an evaluation unit is also provided, which is connected to the camera. In or for determining the tool properties, a first image of the joining tool is acquired by the camera and transmitted to the evaluation unit. Similarly, in or for determining the properties of the joining bodies, a second image of the joining tool and of at least one joining body arranged on the support surface is acquired by the camera and transmitted to the evaluation unit. In addition, a third image with the complex is acquired by the camera and transmitted to the evaluation unit when or for determining the complex property.

The evaluation unit and the camera can be configured as a unit, wherein at least the camera is preferably arranged in a predetermined position and orientation relative to the joining tool.

Furthermore, the camera is in particular a video camera, but instead of a predetermined point in time a single image can also be captured.

In a variant of the method, it is advantageously provided that the first image shows the contact surface of the joining tool. The evaluation unit captures the bearing surface in the first image and determines the degree of soiling and/or the degree of wear of the bearing surface as a tool characteristic. For example, contaminants or copper residues may be left on the bearing surfaces by the previous joining process or joining method. Furthermore, the bearing surface preferably has a geometry that matches the joining process, for example a plurality of grooves or ridges extending over the bearing surface. The degree of wear or damage of this geometry can thus be derived as a tool characteristic by the evaluation unit. For this purpose, at least one surface value, for example a surface curve, is determined from the first image and compared with a predetermined comparison value.

In a further development of the method, an alarm message comprising the degree of soiling and/or the degree of wear is also generated by the evaluation unit as a correction parameter for cleaning and/or replacing the bearing surface. The degree of contamination and/or degree of wear may be, for example, a percentage deviation from a predetermined alignment value. If the degree of contamination and/or the degree of wear exceeds a predetermined wear limit value and/or wear limit value, an alarm message is output to the operator. Alternatively, the warning message can also be output or transmitted, for example, to an automated cleaning or tool changing device. The bearing surface can then be cleaned or the tool element with the bearing surface can be replaced according to the maintenance message.

The second image display support surface and at least one engagement body disposed thereon. The actual position and the actual orientation of the joining body on the support surface in the second image are determined by the evaluation unit. Deviations of the actual position from the predetermined target position and of the actual orientation from the predetermined target orientation are then determined as well as a correction value for correcting the actual position to the target position and a correction value for correcting the actual orientation to the target orientation as the coupling characteristic.

A correction message is then generated by the evaluation unit on the basis of the data obtained by means of the second image, said correction message comprising a corresponding correction value for correcting the actual position of the at least one joining body on the support surface to the target position and/or the actual orientation to the target orientation, said correction value being used as a correction parameter. The correction message is output to an operator or an automated positioning device, for example, by an optical visual display, to position and orient the at least one mating body. The position and orientation can then be corrected by the operator or by the positioning device, so that the position and orientation of the joining body corresponds to the specification for the joining process or for joining the joining bodies. In this way, it is ensured that, in addition to the conventional and independent monitoring of the so-called purely mechanical process parameters (for example the set welding current, the process temperature, the operating force, etc.), it is also possible to monitor these parameters prior to the joining process, which parameters were only checked in the prior art in a subsequent monitoring and evaluation step.

If the bonded body has a position or orientation different from the theoretical value, poor quality connection occurs at the time of bonding, and therefore, the composite body produced without correcting the position or orientation of the bonded body must be sorted out as a defective product thereafter.

For example, if four adapters are connected by a joining method, the four adapters should be stacked on top of each other so that a composite can be produced by the joining method. By acquiring the actual and theoretical positions of the joining bodies, it can be ensured that the joining bodies are in the correct arrangement with respect to one another and are superimposed on one another or that the joining bodies form their correct arrangement, to be precise before they are connected to one another.

The second image display support surface and at least one engagement body disposed thereon. In the method, an actual outer contour of the joining body is acquired in the second image by an evaluation unit and a joining body contour deviation of the actual outer contour of the joining body from a predetermined theoretical outer contour of the joining body is determined as a joining body property. This revealed that the bonded body of the composite bodies of inferior quality was caused in the immediately preceding bonding. Measures for improving the quality can therefore be taken before the joining.

In a further development of the method, a correction message is generated by the evaluation unit, which message includes the contour deviation of the joining bodies, in order to correct the joining bodies or to exclude them from the joining process if the corrected deviation of the joining bodies exceeds a predetermined contour deviation limit value for the joining bodies. For example, at least one of the joining bodies is always a strand, which is formed from a plurality of individual wires. The strand or individual wires of the strand are fanned out or looped when the strand is placed or positioned on the support surface. The fanning out or looping again results in a composite body made of litz wire having a lower quality. Lower quality relates, for example, to a composite that does not have a predetermined shape or a lower force or current carrying capacity than a composite made with modified predetermined parameters. In particular, the individual threads protruding through the litz wire can also hinder subsequent process steps. If, after joining, a heat-shrinkable plastic sleeve is to be wound (glued) or shrunk, so that the regions in which the connection between the joined bodies is established are electrically insulated and protected against moisture, incomplete and inadequate insulation and sealing can be produced, for example, by projecting single wires.

The third image shows the composite. The evaluation unit acquires the actual outer contour and/or the optical actual properties of the composite body in the third image and determines a composite body contour deviation of the actual outer contour of the composite body from a predetermined theoretical outer contour of the composite body and/or a composite body property deviation of the optical actual properties from a predetermined optical theoretical properties as a quality characteristic of the joining process and of the composite body.

In the contour detection, in particular only a part of the entire contour is detected. For example, the surfaces and sides of the joined body or composite body and the end faces corresponding to the cross-section can be obtained. If not the entire contour but only a part of it is acquired, the respective subsequent method step is performed on the basis of the existing information. For example, it can also be checked whether the shape transferred to the composite body by the joining process is formed in its predetermined manner. If, for example, the grooves or projections and recesses are transferred as corresponding recesses from the bearing surface to the composite body during joining, it is possible, depending on the contour and shape of the composite body obtained or the depth of penetration of the projections or recesses in the composite body, to ascertain whether there is a so-called "lack of welding" and to carry out the joining process with too little force and/or too low a temperature.

The optical characteristic obtained may include, for example, the color of the composite or the color of a face of the composite. In particular, when joining joint bodies by means of a method based on temperature increase or ultrasonic welding, the color of the composite body changes as a result of the joining process, wherein process parameters and the quality of the joint can be derived from the color. For example, it can be derived from the color of the composite or of the composite sections between the joining bodies whether so-called "overbonding" has occurred and excessive temperatures have occurred during the joining process.

When the contour deviation of the composite body exceeds a predetermined contour deviation limit value of the composite body and/or the characteristic deviation exceeds a predetermined characteristic limit value, a quality message comprising the contour deviation and/or the characteristic deviation of the composite body is generated by the evaluation unit to determine the quality of the performed joining process.

The quality message is then passed to an operator or an automated picking device to pick out the complexes. Alternatively or additionally, and in particular in the case of a repair of the composite or of a subsequent joining process, a quality message can be output to an operator or a repair device for repairing the subsequent joining process.

The camera and the area optically acquired by it are preferably static and fixed in position. In particular, exactly one camera is also used in this method.

In an advantageous development, the first joining body is a strand which is formed from a plurality of individual wires, and the second joining body is a terminal connection for connecting the strand to the contact element. The terminal connections, also referred to as terminals, are made of an electrically conductive material and preferably have connection means, such as plug connectors; snap-fit means or through holes to connect other components.

In an advantageous development, it is provided that the first joining body and the second joining body are each a strand, which is formed from a plurality of individual wires.

Furthermore, in a variant the strand or the strands have a sheath which is electrically insulated from the strands in the radial direction. The litz wire is in particular formed by an electrical conductor, for example a plurality of individual wires and a sheath surrounding the conductor in the circumferential direction, which is arranged radially inside the cross section of the litz wire. In order to connect the strand to a further strand or to a terminal connection, the strand has a free section on at least one end-side section, the free section being free of a sheath or being separated from the sheath. In the joining method or for joining, no sections of the outer skin are arranged on the bearing surface of the joining tool and should occupy a specific theoretical position.

In a further advantageous method development, the joining method is an ultrasonic welding method. The tool head and/or the bearing surface of the bonding tool is an ultrasonic oscillation unit.

If further sensors are provided on the joining tool to detect process values, the data acquired by the camera or the data determined by the image and evaluation unit are compared directly with the data detected by the sensors for the joining process. For example, a force sensor or a measured value of a force sensor, which determines the clamping force of the clamping element, is checked by means of the properties of the joining body to determine whether the clamping element clamps the joining body, since it can be deduced from the second image whether the joining body is clamped by the clamping element. The position of the parts of the joining tool, for example the position of the bearing surface, the at least one clamping element and the tool head, can also be determined, for example, from the image acquired by the camera and compared with the position values determined by the sensors. The sensor values can be checked and the faulty sensor corrected and identified.

If components of the joining tool, such as the tool head, the bearing surface or the clamping element, are detected by the camera or evaluated by the evaluation unit in the detection of the tool, joint or composite properties, provision is preferably made for a marking element to be arranged or formed on the joining tool. The markers may be, for example, colored dots, QR codes, or raised and recessed portions formed by the respective members. The position of the respective component is easily accessible, for example, by means of a marking.

The features disclosed in the foregoing may be combined in any desired manner, as long as technically possible and without conflicting therewith.

Drawings

Further advantageous developments of the invention are indicated in the dependent claims or are explained in detail below together with the description of preferred embodiments of the invention with reference to the drawings. In which is shown:

fig. 1 shows a first step of the method;

fig. 2 shows a second step of the method;

fig. 3 shows a third step of the method.

Detailed Description

The figures are exemplary schematic diagrams. Like reference numbers in the figures refer to features that are functionally identical and/or structurally identical.

Fig. 1 shows a schematic side view of the bonding tool and the camera 50. The joining tool comprises a movable tool head 42 and a stationary support element 43 for the joining process, wherein in the exemplary embodiment shown the joining bodies 10, 20 are joined by means of an ultrasonic welding method, so that the tool head 42 is an anvil and the support element 43 is an ultrasonic oscillating unit. A first image is acquired by the camera 50 before the joining process, which first image shows the bearing surface 41 in an image section or image region through the first image angle 101 shown. The bearing surface 41 is formed by a bearing element 43 on the side facing the tool head 42. The first image captured by the camera 50 is transmitted to an evaluation unit, not shown, and evaluated. The first image is compared, for example, by an evaluation unit with a comparison image stored in the evaluation unit and a deviation of the actual characteristic from the theoretical characteristic is determined, as a result of which the degree of soiling and/or the degree of wear of the bearing surface 41 shown by the first image can be determined relative to the bearing surface shown by the comparison image. The degree of contamination and the degree of wear correspond to the tool characteristics which are transmitted by means of an alarm message if the degree of contamination and/or the degree of wear exceed predetermined limit values. If the contamination or wear of the bearing surface 41 is too great or exceeds a predetermined limit value, the wear or contamination is reported as a signal to the operator, who can clean the bearing element 43 or the sonotrode or can replace the latter if necessary.

To join the joining bodies 10, 20, the joining bodies are then arranged on the supporting surface 41 as shown in fig. 2. It is important for the connection between the joining bodies 10, 20 to maintain the predetermined parameters. These parameters include, for example, the position and orientation of the joining bodies 10, 20 on the supporting surface 41 and the orientation of one another. In addition, the joined bodies 10, 20 must be superimposed in a predetermined manner. In the exemplary embodiment shown, the joining bodies 10, 20 are each a braided wire made of a plurality of individual wires, wherein the braided wire has a sheath 12, 22 or a

section

11, 21 without a sheath 12, 22. In order to connect the joining bodies 10, 20 to one another, sections of the litz wire without the outer jacket 12, 22 are arranged in the joining tool or on the support surface 41. The parameters which are preferably to be acquired by the camera 50 and which are to be checked by the evaluation unit are that the sheath 12, 22 of the litz wire is arranged outside the joining tool.

If the joining bodies 10, 20 are arranged on the support surface 41, a second image is acquired by the camera 50 and transmitted to the evaluation unit. Different adapter body characteristics can be derived from the second image by the evaluation unit via the schematically illustrated image angles 201, 202, 203 and compared with predetermined parameters.

For example, it can be derived from the second image angle 201 whether the strand or the sheath of one of the coupling bodies 10, 20 extends as far as between the tool head 41 and the support element 43. If this is the case, the checking of the coupling bodies 10, 20, the reorientation and/or the replacement can be authorized by informing the operator of the coupling tool of the correction message.

Furthermore, the registration of the joining bodies 10, 20 with one another can be checked by means of the image portions of the second image taken at the third image angle 202. In the second image, it can be seen via the image section acquired by means of the third image angle 202 whether the joining bodies 10, 20 are displaced relative to one another in the transverse direction orthogonal to the plane of the representation of fig. 1 to 3 or completely coincide with one another. If the joined bodies 10, 20 are moved relative to one another, the connections or transitions between the joined bodies may not have sufficient current and/or force carrying capacity for the composite body 30 during joining. If such a movement of the coupling bodies 10, 20 is detected, a correction message can be transmitted to the operator by the evaluation unit, for example by means of an optical display on a monitor, and the operator is asked to make the correction. A new orientation and the resulting coincidence or movement can be acquired again by the camera 50 and the process repeated until the predetermined coincidence of the joining bodies 10, 20 is reached.

The second image also includes, in the image section acquired by the fourth image angle 203, the actual position and the actual orientation with respect to the joining body 20 directly resting or resting on the support surface 41. The actual position and the actual orientation of a further joining body 10, which is not placed directly on the support surface 41, can also be derived from the image section acquired by the third image angle 202 and the fourth image angle 203. By means of the known and fixed orientation of the camera 50 relative to the joining tool and in particular relative to the supporting element 43 or the supporting surface 41, the actual position and the actual orientation of the joining bodies 10, 20 can be determined from the second image and compared with a predetermined theoretical position or theoretical orientation. In particular, if the actual value deviates from the setpoint value beyond a predetermined limit value, a correction value is determined by the evaluation unit from the deviations of the actual position from the setpoint position and of the actual orientation from the setpoint orientation, or respectively determined. The correction value or values are displayed to the operator. The actual position and the actual orientation are then determined again and, if necessary, corrected by the operator until the actual position and the actual orientation are within the error determined by the limit values.

The joining process or joining of the joining bodies 10, 20 takes place only if the joining bodies 10, 20 are arranged on the supporting surface 41 in their predetermined manner or with predetermined parameters. For this purpose, the tool head 42 is moved with a predetermined force in the direction of the support element 43. If the joining bodies 10, 20 are arranged with a predetermined force between the support surface 41 or the support element 43 and the tool head 42, ultrasonic vibrations are transmitted to the joining bodies 10, 20 at least via the support element 43 and the joining bodies are thereby welded to one another.

A composite body 30 schematically shown in fig. 3 is formed from the joined bodies 10, 20 by welding. In this case, a transition region 31 is produced between the sections of the joining bodies 10, 20 that lie against one another, in which the joining bodies 10, 20 are joined together by material. The force with which the joining bodies 10, 20 are pressed against one another between the tool head 42 and the support element 43 also transmits the shape of the support surface 41 and the surface of the tool head 42 facing the support surface 41 to the joining bodies 10, 20.

A third image is acquired from the complex 30 by the camera. By means of the image section of the third image, which is acquired at the fifth image angle 301, the shape of the surface 32 of the composite body 30 impressed by the tool head or of the depressions transferred by the tool head onto the composite body 30 and at the same time the color of the surface 32 can be acquired. By means of the evaluation unit and a suitable comparison it can be derived from the color and shape of the surfaces whether excessive or insufficient welding has occurred during the joining process, i.e. whether the joined bodies 10, 20 have been joined in the ultrasonic welding at too high or too low a process temperature and/or too high or too low a force, for example whether a preset mechanical value has been set correctly. The shape of the complex in the transverse direction orthogonal to the plane of the schematic may be acquired from the image portion of the third image acquired through the seventh image angle 302. The shape of the complex in the transverse direction can also be compared with suitable theoretical values or comparison images by means of an evaluation unit. For example, it can be determined whether monofilaments or other protrusions have emerged from the composite body 30 in the transverse direction and have an effect on the subsequent process sequence. If the evaluation unit determines from the third image that the composite body 30 is welded too far or not sufficiently and has a wrong cross-sectional shape, the finished composite body 30 can be sorted out as a defective product.

The embodiments of the invention are not limited to the preferred examples given. Rather, a plurality of variants is conceivable, which can use the illustrated variant even in fundamentally different types of embodiments.

Claims

1. A method for monitoring a joining process on a joining tool for joining at least two joining bodies (10, 20) to form a composite body (30), wherein at least one joining body is a litz wire, wherein,

the joining tool comprises a support surface (41) for supporting one of the joining bodies (10, 20), at least one clamping element for temporarily securing the joining bodies (10, 20) to one another during a joining process, and a tool head (42) for continuously joining the joining bodies (10, 20) to form a composite body (30), and wherein,

at least one camera (50) is provided, by means of which at least a part of the bonding tool is optically acquired, wherein,

optically capturing the bonding tool by means of the camera (50) before bonding the bonded bodies (10, 20) and determining the tool characteristics of the bonding tool from the optical capturing,

optically acquiring at least one of the bonded bodies (10, 20) by the camera (50) before bonding the bonded bodies (10, 20) and determining a bonded body characteristic of the acquired bonded body (10, 20), and

optically capturing the complex (30) by means of the camera (50) and determining a complex property during and/or after the joining of the joining bodies (10, 20) to a complex (30), wherein,

correction parameters for correcting the joining process and/or quality characteristics for determining the quality of the joining process and the composite (30) are determined from the tool, joint and composite characteristics.

2. The method of claim 1, wherein

An evaluation unit is also provided which is connected to the camera (50), and

upon determination of the tool characteristic, a first image of the joining tool is acquired by means of the camera (50) and transmitted to the evaluation unit,

in order to determine the joining body properties, a second image of the joining tool and of at least one joining body (10, 20) arranged on the support surface (41) is acquired by means of the camera (50) and transmitted to an evaluation unit,

in the determination of the complex property, a third image with the complex (30) is acquired by the camera (50) and transmitted to an evaluation unit.

3. The method of claim 2, wherein

The first image shows the bearing surface (41) of the joining tool and the bearing surface (41) is acquired in the first image by the evaluation unit and the degree of soiling and/or the degree of wear of the bearing surface (41) is determined as a tool characteristic.

4. The method of claim 3, wherein

An alarm message comprising the degree of contamination and/or degree of wear is generated by the evaluation unit as a correction parameter for cleaning and/or replacing the bearing surface (41) and is output to an operator if the degree of contamination and/or degree of wear exceeds a predetermined wear limit value and/or wear limit value.

5. The method of any one of claims 2 to 4, wherein

The second image shows the supporting surface (41) and at least one joining body (10, 20) arranged thereon, and the actual position and the actual orientation of the joining body (10, 20) on the supporting surface (41) are determined in the second image by the evaluation unit, and deviations of the actual position from a predefined target position and the actual orientation from a predefined target orientation and corrections for correcting the actual position to the target position and for correcting the actual orientation to the target orientation are determined as joining characteristics.

6. The method of claim 5, wherein

A correction message comprising a corresponding correction value for correcting the actual position of the at least one coupling body (10, 20) on the support surface (41) to the theoretical position and/or the actual orientation to the theoretical orientation is generated by the evaluation unit and output to an operator or an automated positioning device for positioning and orienting the at least one coupling body (10, 20).

7. The method of any one of claims 2 to 4, wherein

The second image shows the bearing surface (41) and at least one joining body (10, 20) arranged thereon and the actual outer contour of the joining body (10, 20) is captured in the second image by the evaluation unit and a contour deviation of the joining body (10, 20) of the actual outer contour of the joining body (10, 20) from a predefined theoretical outer contour of the joining body (10, 20) is determined as a joining body property.

8. The method of claim 7, wherein

Generating, by the evaluation unit, a correction message comprising the profile deviation of the joining bodies (10, 20) for correcting the joining bodies (10, 20) or for excluding the joining bodies (10, 20) from the joining process if the corrected deviation of the joining bodies (10, 20) exceeds a predetermined profile deviation limit value of the joining bodies (10, 20).

9. The method of any one of claims 2 to 4, wherein

The third image shows the composite body (30) and the actual outer contour and/or the actual optical properties of the composite body (30) are recorded in the third image by the evaluation unit and the contour deviation of the composite body (30) of the actual outer contour of the composite body (30) from a predefined theoretical outer contour of the composite body (30) and/or the property deviation of the composite body (30) of the actual optical properties from a predefined theoretical optical properties are determined as quality features of the joining process and of the composite body (30).

10. The method of claim 9, wherein

When the contour deviation of the composite body (30) exceeds a predetermined contour deviation limit value and/or a characteristic deviation of the composite body (30) exceeds a predetermined characteristic limit value, a quality message comprising the contour deviation and/or the characteristic deviation of the composite body (30) is generated by the evaluation unit in order to determine the quality of the performed joining process.

11. The method of claim 10, wherein

-passing said quality message to an operator or an automated selection device for selecting said complex (30), and/or

And outputting the quality message to an operator or a correcting device to correct the subsequent jointing process.

12. The method of any one of claims 1 to 4, wherein

The first coupling body is a stranded wire composed of a plurality of element wires, and the second coupling body is a terminal connector for connecting the stranded wire with the contact member.

13. The method of any one of claims 1 to 4, wherein

The first and second bonded bodies are each a twisted wire, and each twisted wire is formed of a plurality of individual wires.

14. The method of any one of claims 1 to 4, wherein

The strand has a sheath (12, 22) which is electrically insulated from the strand in the radial direction and

the sections of the strand without the sheath (12, 22) are arranged on a bearing surface (41) of the joining tool for joining.

15. The method of any one of claims 1 to 4, wherein

The joining method is an ultrasonic welding method and

the tool head (42) and/or the bearing surface (41) of the joining tool are/is an ultrasonic oscillating unit.