EP2379273A1

EP2379273A1 - Welding unit and welding method

Info

Publication number: EP2379273A1
Application number: EP09740117A
Authority: EP
Inventors: Andreas Josef Birnesser; Reiner Ramsayer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2008-12-17
Filing date: 2009-10-20
Publication date: 2011-10-26
Also published as: US20120175353A1; WO2010069643A1; JP2012512031A; DE102008054798A1

Abstract

The invention relates to a welding unit (1), having an energy source (4), in particular a laser beam source, for implementing a heat input for welding a first component (2) to at least one second component (3) in a connection area (5) and to a sensor (8) for detecting the process radiation (10) of the welding process. It is proposed according to the invention that the sensor (8) comprises a measuring lance (7). Furthermore, the invention relates to a welding method.

Description

5 description

Welding arrangement and welding process

State of the art L o

The invention relates to a welding arrangement for welding at least two components according to the preamble of claim 1 and to a welding method according to the preamble of claim 12.

L 5 In laser welding, in particular of automotive and automotive components, the reproducible production of the seam characteristics, such as the welding depth, the seam surface, the seam width, etc. is often only possible in a small process window. In particular, this problem occurs when laser welding thin sleeves or when joining thick to thin components

> 0, ie when a thicker joining partner is to be welded into a thinner joining partner, without welding through the thinner joining partner.

A method is known from DE 10 2004 050 164 A1, in which the process radiation correlating with the process temperature is used as a control variable with a sensor (pyrometer) in order to regulate the laser beam power. In this case, it is assumed that the component-side process radiation (temperature radiation) correlates with the welding depth and that a control loop can be built up. In principle, however, the known method 30 is used only where the back of the component of the welding process is accessible by today's conventional optical sensors. In contrast, the method is not applicable in wells, thin sleeves, etc. due to the limited accessibility for conventional sensors. Disclosure of the invention

The invention is therefore based on the object to propose a welding arrangement with which the process radiation of the welding process in wells 5, thin sleeves, circumferentially closed components, etc. can be detected easily, in particular to be able to regulate the performance of the energy source to realize the heat input , Furthermore, the object is to provide a correspondingly optimized welding method.

This problem is solved with regard to the welding arrangement with the features of

Claim 1 and with respect to the welding method with the features of claim 12 solved. Advantageous developments of the invention are specified in the subclaims. In the context of the invention, all combinations of at least two of in the description, the claims fall

L 5 and / or the figures disclosed features. In order to avoid repetition, features disclosed according to the device should be regarded as disclosed according to the method and be able to be claimed. Likewise, according to the method disclosed features should be considered as device disclosed and claimed claimable.

The invention is based on the finding that conventional sensors with an end-side optical sensor element are not suitable for insertion into indentations, peripherally closed components such as sleeves, etc., and certainly not for measuring in the radial direction. In order to be able to measure the temperature of the abovementioned components without

In order to enable a process radiation of the welding process which correlates with the temperature, preferably on the side remote from the energy source, the invention proposes that the sensor, which is preferably designed as a pyrometer, comprises a measuring lance or is preferably designed as a measuring lance. Under a measuring lance is an elongated, in particular

30 rod-shaped, preferably thin, i. To understand a small diameter embodiment, which allows the sensor, at least in sections, in wells, peripherally closed components, etc. introduce so as to detect the process radiation, in particular their intensity on the inside. It is particularly preferred when the energy source is on

35 of the outside, preferably always at the same circumferential position of the components as the measuring lance, is located. Further preferred is an embodiment of the Welding arrangement in which this is designed as a laser welding arrangement, the energy source is thus designed as a laser beam source. The welding arrangement according to the invention can be used both for the production of circumferential welding seams and for spot welding.

5

An embodiment of the welding arrangement in which the first and / or the second component is sleeve-shaped, preferably circumferentially closed, is / are very particularly preferred, so that the measuring lance for detecting the temperature of the welding process in at least one of the two components along the

L O longitudinal extent of the measuring lance must be introduced in order to detect the temperature of the welding process on the inside of at least one of the two components, in particular on the inner circumference (inner circumferential surface) of at least one of the two components or component combination. Further particularly preferred is an embodiment of the welding arrangement in which the minimum

L 5 least two components have a different thickness extent, wherein preferably the component is arranged with the larger, in particular radial, thickness extension outside the thinner component, so that the thinner component through the thicker components through from the outside by means of the energy source, in particular a laser beam source, is heated. With the help of

> 0 lance-shaped sensor can be taken to ensure that the thinner

Component is not welded through during the welding process, especially when, as will be explained later, the power of the power source in response to the process radiation and thus is regulated in dependence on the temperature of the welding process. In other words, the preferred

15 of the sensor detected process radiation, the control variable for regulating the

Energy performance, the energy source, in particular the laser beam source.

With respect to the longitudinal extent of the measuring lance, laterally, i. from the radial direction, to be able to detect a temperature of the welding process is in

30 development of the invention advantageously provided that a measuring axis

(Measuring direction) is arranged at an angle to the longitudinal axis of the measuring lance. The measuring axis is the direct connecting line between the so-called "hot spot", ie the hottest point and the measuring lance, preferably an optical sensor element of the measuring lance

35 measuring axis perpendicular to the surface extension of such a sensor. Preferably, the measuring axis is at an angle from an angular range between about 10 ° and about 170 °, preferably between about 30 ° and about 150 °, more preferably between about 50 ° and about 130 °, most preferably between about 70 ° and about 1 10 °, arranged to the longitudinal axis of the measuring lance. For most applications it is advantageous to use the measuring axis

5 at least approximately perpendicular to the longitudinal extent of the measuring lance or form the measuring lance so that it gives such a position of the measuring axis in relation to the longitudinal axis of the measuring lance. It is further preferred if the measuring axis coincides at least approximately with the longitudinal axis of a laser beam of the energy source.

L O

In a further development of the invention is advantageously provided that the first and the second component are arranged rotatable relative to the measuring lance and the energy source. In this case, it is possible for the first and the second component to be roughened together relative to the stationary measuring lance and the fixed energy source.

L 5 animals. It is also possible to arrange the two components stationary and the

Rotate measuring lance together with the energy source. Furthermore, an embodiment can be realized in which all the aforementioned parts rotate, wherein preferably the measuring lance, at least with its detection range, is at the same circumferential position of the two components at all times as the energy.

10 source of energy or emitted by her laser beam.

For detecting the process radiation and thus the temperature of the welding region, the sensor preferably comprises at least one sensor element, in particular a photodiode or a photodiode array.

> 5

With regard to the arrangement of the aforementioned sensor element, in particular the at least one photodiode, there are different possibilities. Thus, the at least one sensor element, for example, directly on the measuring lance, preferably in a front region of the measuring lance, quite definitely

30 particularly preferably be arranged on a radiation receiving portion of the measuring lance, ie at a portion of the measuring lance, which is adjacent to the connection region of the two components during operation of the welding arrangement and thus directly, preferably without prior deflection, detect the heat radiation. In the case of such an arrangement of the minimum

At least one sensor element, the sensor signal from the sensor element wirelessly to a spaced from the radiation receiving portion Auswer- teeinrichtung be sent. Preferably, however, a transmission via a cable connection, wherein the cable connection is guided along an adjacent to the radiation receiving portion of the measuring lance rod-shaped portion of the measuring lance to the outside.

5

In an alternative embodiment, the sensor element is arranged at a distance from the radiation receiving section of the measuring lance and not a sensor signal is transported along the bar section, but the process radiation to be detected by the sensor element. It is particularly preferred

L O if the length of the rod section of the measuring lance is greater than

5cm, preferably greater than 10cm, more preferably greater than 15cm, more preferably greater than 20cm, is to be able to comfortably detect the temperature of the welding process even in large component depths.

L 5 For the last-mentioned embodiment, at least one optical fiber (light guide) for guiding the radiation from the radiation-receiving section to the sensor element is to be provided in and / or on the rod section.

Additionally or alternatively, it is possible to use the rod section directly as a light guide.

10 ladder, for example, by the rod conductor is performed as a glass rod. In this case, the glass rod can be designed as a hollow rod which is highly reflective coated on the inside, in particular a hollow cylinder, or as a solid material rod coated with a high reflectivity on the outside. The formation of the measuring lance, at least of the rod portion, as a glass rod has the advantage that a mechanical

15 stabilization can be dispensed with, since the light guide itself the mechanical

Function of the measuring lance takes over. The glass rod is adapted to the wavelength of the process radiation to be detected and preferably carried out such mirrored that light remains within the glass rod. At the tip of the glass rod, ie in the region of the radiation receiving section, can advantageously

If necessary, a lens surface is sanded which is preferably not mirrored in order to capture as much process radiation as possible from the "hot spot" and bring it into the glass rod. The aforesaid sensor and optionally at least one optical filter are preferably located on the end of the glass rod facing away from the radiation receiving section. Advantageous

In one embodiment of the glass rod as a hollow rod is that the radiation can propagate in air. Since glass always has a wavelength-dependent possesses sorption coefficient, this form of the measuring lance prevents certain wavelengths are attenuated or blocked in their intensity. This is advantageous in particular when electromagnetic process radiation in the UV or in the far IR range is to be observed, since glass is generally not transparent for this region.

Particularly preferred is an embodiment in which a radiation deflecting device, in particular a mirror, is provided in the radiation receiving section of the measuring lance, with which the radiation, in particular from the side, is at least approximately deflectable in the direction of the longitudinal extension of the measuring lance.

Particularly preferred is an embodiment of the welding arrangement in which, as indicated at the outset, the power of the energy source is determined as a function of the sensor radiation detected by means of the sensor and thus as a function of

Temperature is adjustable. This control is preferably carried out by the evaluation device, which then preferably acts simultaneously on the energy source in a controlling manner.

10 Furthermore, the invention leads to a welding process. The invention

The method is characterized in that the sensor is designed in the form of a measuring lance, or comprises a measuring lance, in order also in recesses or peripherally closed components on the inside of the components, the process radiation of the welding process, in particular for control purposes of the energy.

15 giequellenleistung be detected.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. These show in: 30

1 is a schematic representation of a comparison of a conventional sensor according to the prior art, and a sensor with measuring lance, 2 shows an alternative welding arrangement with a sensor designed as a measuring lance, in which a sensor signal is guided through a rod section,

FIG. 3 shows an alternative embodiment of a welding arrangement with a measuring-lance-shaped sensor, the detected process radiation being guided through the rod-shaped section of the measuring lance by an optical waveguide, FIG.

4 shows a further alternative embodiment of a welding arrangement with a measuring-lance-shaped sensor whose measuring lance itself is designed as an optical waveguide, for example as a mirrored solid material glass rod or as a mirrored metal hollow rod, and

L 5

5 shows a further alternative embodiment of a welding arrangement with a beam deflecting device on a radiation receiving section of the measuring lance.

10 In Fig. 1, a welding assembly 1 is shown. The welding arrangement 1 comprises a first, cup-shaped and a second, sleeve-shaped component 2, 3, which are welded together by means of an energy source 4, in this case a laser beam source, in a connection region 5. In the process, the inner, thinner-walled component in the welding region 5 is passed through the outer component 3 by means of a

15 laser beam 6 melted. To monitor the temperature of the

Welding process correlating process radiation is a measuring lance 7 comprehensive sensor 8 is provided. The measuring lance 7 makes it possible to detect the process radiation of the welding process on the inner circumference of the component 2. Such a temperature detection would be with one in the drawing plane

30 right-indicated prior art pyrometer 100 not possible, since this is not inserted into the sleeve-shaped member 3 and can measure only in the axial direction of a temperature or absorb heat radiation.

The measuring lance 7 comprises a front radiation receiving section 9 arranged on the left in the plane of the drawing, onto which the process radiation 10 of the welding process impinges directly. It is noteworthy that an (imaginary) Measuring axis 1 1, here a direct line connecting a measuring spot 12 and a sensor element (photosensor) 13, at right angles to the longitudinal extent, ie to the longitudinal axis L of the measuring lance 7 runs. The example designed as a photodiode or photodiode array sensor element 13 is located in

5 aforementioned, front radiation receiving portion 9 of the measuring lance 7. The

Sensor 13 is signal-conducting via a cable connection 14 with an outside of the components 2, 3 arranged evaluation device 15. The cable connection 14 is guided for this purpose by a rod-shaped portion 16 (rod portion) of the measuring lance 7 in the axial direction. The evaluation device 15 is identical

L O formed timely as a control device and adjusts the power of the power source 4 as a function of the intensity of the detected process radiation, preferably in such a way that no penetration welding of the inner member 2 takes place.

In the exemplary embodiment shown, the energy source 4 and the measurement L ze ze 7 of the sensor 8 are arranged stationary, wherein the components 2, 3 are rotated about a longitudinal axis of the component. The measuring spot 12 is to be positioned below the "hot spot" at all times in order to allow an exact regulation of the power of the energy source 4. Alternatively, it is possible to additionally or alternatively to a component rotation the measuring lance 7 and the energy source 4 or alternatively only In this case, care must be taken that the laser beam 6 and the measuring lance 7 move synchronously so that the measuring spot 12 of the measuring axis 11 is at any time immediately below the "hot" laser beam. Spots "is located.

If necessary, the welding arrangement according to FIG. 1 can have optical filters, not shown, via which the spectral range to be detected can be selected for the measurement. Additionally or alternatively, a corresponding optical system, for example a lens or a lens assembly, can be realized for a focus on the "hot spot" (hottest point under the weld)

30 will be.

FIG. 2 shows a similarly constructed welding arrangement 1, wherein for reasons of clarity the representation of the energy source 4 and of the evaluation device 15 has been dispensed with. The sensor element 13, which is arranged in the front radiation receiving section 9 of the measuring lance 7, can be seen. A

Cable connection 14 for passing electrical signals from the sensor Mentes 13 to the evaluation device 15 is passed through the rod-shaped portion 16 of the measuring lance 7.

Another alternative embodiment of a welding arrangement 1 is shown in FIG. Here the measuring lance 7 is equipped with an optical fiber 17, for example a glass fiber. The front end 18 of the optical fiber 17 is oriented parallel to the longitudinal axis L of the measuring lance 7, resulting in a perpendicular orientation of the measuring axis 11 relative to the longitudinal axis L results. In other words, the optical fiber 17 is arranged such that the radiation L O 10 can be received from the radial direction with respect to the longitudinal axis L of the measuring lance 7.

The optical fiber 17 extends from the front radiation receiving portion 9 of the measuring lance 7 to one at the end of the rod-shaped one

L 5 section 16 of the measuring lance 7 arranged sensor element 13, which is signal-conducting connected to the evaluation device 15, analogous to FIG. 1. The optical fiber 17 collects in the illustrated construction, the temperature radiation according to its acceptance angle and passes them within the optical fiber 17 optionally through a not shown filtering through

10 sensor element 13, for example a photodiode. If required, the optical fiber 17 may have an optical structure, not shown, for example via at least one lens, in particular in the region of the front end side 18, whereby a more precise focusing is possible. Additionally or alternatively, optical filters may be provided to select the spectral range,

15 which are preferably already arranged in the radiation receiving section 9, more precisely in the region of the end face 18 of the optical fiber 17. Furthermore, by suitable doping or changing the optical properties of the fiber 17, the optical filtering can already be performed within the optical fiber 17.

30

FIG. 4 shows a further alternative exemplary embodiment of a welding arrangement 1. The measuring lance 7 used there is designed as such as a light conductor 19. In other words, the optical fiber 19 assumes the mechanical support or holding function of the measuring lance 7. In the shown in Fig. 4

35 embodiment is the measuring lance 7 to a massive

Glass rod adapted to the wavelength of the desired process beam to be detected. is adjusted. The glass rod is mirrored with a mirror coating 20, ie designed to be highly reflective, so that the light remains within the glass rod. The section of the measuring lance 7 which forms the radiation receiving section 9 has a ground lens surface 21 and is not mirrored.

5 out, so that as much temperature radiation is captured by the measuring spot 12 and is spent in the glass rod. At the end remote from the radiation receiving portion 9 of the measuring lance 7 and the glass rod, a sensor element 13, for example, a photodiode is arranged. Also provided there optical filters are not shown.

L O

It is alternatively also an embodiment feasible, in which the glass rod is not made of solid material, but as, preferably cylindrical, hollow bar. In this case, the inner surface of the glass rod must be highly reflective coated for the radiation to be observed. An advantage of this embodiment

The reason is that the process radiation can spread in air. Since glass always has a wavelength-dependent absorption coefficient, this type of measuring lance 7 prevents certain wavelengths from being attenuated or blocked in their intensity.

> 0 In another alternative, not shown embodiment, instead of a glass cylinder and a metallic cylinder (hollow metal rod) are used, which performs a similar function and is coated on the inner circumference highly reflective.

FIG. 5 schematically shows a further simplified illustration of a welding arrangement 1. This comprises a light guide 19 and a beam deflection device 22, in this case in the form of a mirror arranged on the light guide 19 in the radiation receiving section 9, which transmits the process radiation 10 emitted by the measuring spot 12 into the measuring lance 7 diverted into it. It can be seen that at

In the embodiment shown, the measuring axis 1 1 is arranged at an angle to the longitudinal axis L of the measuring lance 7, here at an angle of approximately 95 °.

As can be further seen in FIG. 5, lenses 23 for focusing the recorded projection radiation 10 are provided immediately adjacent to the beam receiving section 9. At the end of the measuring lance 7 is an optical sensor 13 for receiving the guided through the rod-shaped portion 16 of the measuring lance 7 process radiation. The sensor element 13 is, as in the preceding embodiments, signal-conducting connected to an evaluation device 15, which is at the same time a control device for regulating the power of the energy source, not shown in FIG. 5 for reasons of clarity.

Claims

Claims 5

1. Welding arrangement, with an energy source (4), in particular a laser beam source, for realizing a heat input for welding a first component (2) with at least one second component (3) in a connection region (5) and with a sensor (8) for detecting the process radiation (10) of

L O welding process,

characterized,

the sensor (8) comprises a measuring lance (7). L5

2. Welding arrangement according to claim 1, characterized in that the first and / or the second component (2, 3) sleeve-shaped, preferably circumferentially closed, is / are formed, and that the measuring lance (7) in the first 10 and / or the second component (2, 3) is inserted and / or inserted in order to detect the process radiation (10) of the welding process on the inside, in particular on the inner circumference, of the first and / or second component (2, 3).

3. Welding arrangement according to one of claims 1 or 2, characterized in that a measuring axis (1 1) at an angle from an angle range between about 10 ° and about 170 °, preferably between about 30 ° and about 150 °, preferably between about 50 ° and about 130 °, more preferably between about 70 ° and about 110 ° to a longitudinal axis of the measuring lance (7) is arranged. 30

4. Welding arrangement according to one of the preceding claims, characterized in that the first and the second component (2, 3) rotatable relative to the measuring lance (7) and the power source (4) are arranged. 35

5. Welding arrangement according to one of the preceding claims, characterized in that the sensor (8) comprises a sensor element (13) for detecting process radiation (10), in particular a photodiode or a photodiode array. 5

6. Welding arrangement according to claim 5, characterized in that the sensor element (13) in a adjacent to the connection region (5) arranged radiation receiving portion (9) of the measuring lance (7) is arranged

L 0 and the sensor signal wirelessly or along a rod-shaped portion (16) of the measuring lance (7), in particular by means of at least one cable, to an evaluation device (15) is guided, or that the sensor element (13) at a distance from the radiation receiving portion (9 ) is arranged and the process radiation (10) guided along the rod portion to the evaluation device (15)

L is 5.

7. Welding arrangement according to claim 6, characterized in that for guiding the process radiation (10) along the rod section (16) 10 at least one optical fiber (17) is provided.

8. Welding arrangement according to one of claims 6 or 7, characterized in that the rod portion (16) for guiding the process radiation (10) along the> 5 rod portion (16) as, in particular internally mirrored, light guide (19), preferably as a solid glass rod or as, in particular metallic or glass, hollow rod is formed.

9. Welding arrangement according to one of claims 6 to 8, characterized in that a radiation deflecting device (22) is arranged in the radiation receiving section (9).

10. Welding arrangement according to one of claims 6 to 9, 35 characterized in that the length of the rod section (16) is greater than 5 cm, preferably greater than 10 cm, particularly preferably greater than 15 cm, more preferably greater than 20 cm.

5 1. Welding arrangement according to one of the preceding claims, characterized in that the power of the energy source (4) in dependence of the means of the sensor (8) detected process radiation (10), in particular the process radiation intensity, is controllable.

L O

12. Welding method, in which an input of heat for welding a first component (2) with at least one second component (3) in a connection region (5) is realized with an energy source (4) and in which the process radiation ( 10) of the welding process is detected,

L 5 characterized

the sensor (8) comprises a measuring lance (7).

10 13. A welding method according to claim 12, characterized in that the first and / or the second component (2, 3) sleeve-shaped, preferably circumferentially closed, is / are formed, and that the measuring lance (7) in the first and / or the second component (2, 3) is introduced to process the process radiation inks.

> 5 sity of the welding process on the inside, in particular on the inner circumference of the first and / or second component (2, 3) to detect.

14. Welding method according to one of claims 12 or 13, characterized

30 that the first and the second component (2, 3) relative to the measuring lance (7) and the

Power source (4) are rotated.

15. Welding method according to one of claims 12 to 14, characterized

35 that the energy output of the energy source (4) depends on the means of the Sensor (8) detected process radiation (10), in particular the process radiation intensity is controlled.