DE102013214551B4 - Wire nozzle and method for laser joining with filler wire with tactile wire guide - Google Patents

Abstract

Wire nozzle, set up for feeding an additional wire in a laser joining process with tactile wire guidance, with: - a nozzle body (12) with a longitudinal axis (14), - a channel (100; 100A) which is in the nozzle body (12) along the longitudinal axis (14 ) is formed, - wherein the channel (100; 100A) has at least a first conically tapered section (142; 142A) in the direction of a wire passage (20), which ends in a central region of the channel (100; 100A), - wherein the Channel (100; 100A) has a wire guide area (150) which is arranged behind the first conically tapered area (142; 142A) in the wire travel direction (20).

Description

The present invention relates to a wire nozzle and a method for laser joining with filler wire with tactile wire guidance. In laser joining processes, such as laser welding processes or laser soldering processes, it is often desirable or necessary to add an additional material. This can be supplied to the joint, for example in the form of an additional wire, such as a welding wire or solder wire.

For this purpose, for example, a wire feed system is used that unwinds the wire and guides it to the desired location. The wire feed system can, for example, have at least one wire conveyor, a feed device, such as a hose or a tube, and a wire guide head and can be, for example, a push-push system. The wire guide head also has a wire nozzle through which the wire is guided. The wire emerges from the front of the wire nozzle to be fed to the joint.

Furthermore, the wire guide head can have a gas nozzle. This can, for example, be arranged on the outside of the wire nozzle and serve to allow a protective gas to flow out around the additional wire. This allows the melting point to be completely covered with protective gas.

Fumes and spatters arise at the melting point during the joining process. During operation, the fumes can lead to deposits on the wire nozzle and make it unusable. Likewise, the feed of the wire through the nozzle causes abrasion that can become lodged in the nozzle. This can lead to flow disruptions and thus to process errors or system downtimes. The time that a wire nozzle can be used before it needs to be replaced is also known as its service life. Short service lives of the wire nozzles mean both high material costs and high process costs, since the joining process has to be interrupted to replace the wire nozzles.

The publication JP 2000-351 090 A shows a wire nozzle used in a laser spray process.

The publication JP H07 - 314 163 A , JP 2005- 224 837 A and DE 10 2011 002 931 A1 show wire nozzles that are used in laser joining processes.

The printed matter WO 2013 / 068 665 A1 , DE 602 06 184 T2 , DE 689 06 429 T2 show nozzles that are designed for use in a laser cutting process.

From the publications DE 10 2010 005 896 A1 and DE 10 2010 051 941 A1 Other laser welding processes are known.

It is therefore the object of the invention to provide a wire nozzle which has the longest possible service life and at the same time is simple and inexpensive to produce and which can be assembled quickly and with little effort. Furthermore, a reliable and cost-effective method for feeding a filler wire to a laser joining process should be specified.

For this purpose, the invention provides a wire nozzle according to claim 1 and a method according to claim 11.

With regard to the device, the object of the invention is achieved by a wire nozzle with a nozzle body with a longitudinal axis. A channel is formed in the nozzle body along the longitudinal axis. The channel has at least a first conically tapered section in the direction of a wire passage, which ends in a central region of the channel.

This is based on the idea that laser joining processes only require guiding the wire, but not electrical contacting of the wire. Due to the special design of the channel, in particular due to the conical taper arranged in the middle area of the channel, the contact area between the wire and the channel wall is minimized, whereby the abrasion in the channel can be significantly reduced while the positionability of the wire is maintained. This makes it possible to provide wire nozzles with a long service life. There are fewer wire running problems, which increases system availability and reduces the number of errors. The channel geometry is also easy to implement and thus enables inexpensive production of the wire nozzle. In particular, the channel geometry makes it possible to produce wire nozzles that have the same external dimensions as conventional wire nozzles and are therefore compatible with a variety of wire feed systems.

The nozzle body of the wire nozzle is preferably an elongated body which is completely penetrated by the channel along its longitudinal axis, that is to say the channel extends from an inlet opening at the rear end of the nozzle body, where the additional wire is inserted during operation, to an outlet opening at the front end of the Nozzle body where the wire leaves the wire nozzle. The Nozzle body can be made of different materials, for example it can consist of a metal or a metal alloy, a ceramic material or a plastic. Typical metallic materials include hard metals, copper or copper alloys. The nozzle body can alternatively also consist of a composite material, for example a core made of a copper alloy with a hardness of 165 +/- 10 HV1 and a jacket surrounding the core of a further copper alloy with a hardness of 115 +/- 10 HV1.

The wire is guided through the channel of the wire nozzle and positioned over the joint using the wire nozzle. The channel preferably has a circular cross section. The channel can be arranged rotationally symmetrically to the longitudinal axis. The channel is designed as a closed channel, i.e. the channel is surrounded by a channel wall transversely to the longitudinal axis. The channel is divided into two areas: the wire inlet area, which is adjacent to the inlet opening, and the wire guide area, which is adjacent to the outlet opening. The total length of the channel results from the distance between the inlet opening and the outlet opening. The wire preferably runs directly through the channel, i.e. no further devices are provided between the channel wall and the wire in either the wire guide area or the wire inlet area. In particular, there is no forced contact between the wire and the channel wall.

The wire inlet area is used to receive the wire from a wire feed device. The wire inlet area has a diameter in the area of the inlet opening, for example, which is a multiple of the diameter of the wire to be used, for example three times or more. The wire inlet area extends into a central area of the channel or the wire nozzle. The middle area is defined as an area that - viewed in the longitudinal direction of the channel - makes up the middle 50 percent (%) of the channel, i.e. the area of the channel that covers both 25% of the total length of the channel from the inlet opening and from the outlet opening is removed.

The wire inlet area can preferably extend over at least 30 percent (%) of the total length L of the channel, or for example over at least 35% or at least 40% of the total channel length. In addition, the wire inlet area can, for example, extend over a maximum of 50% of the total channel length. The length of the wire inlet area can preferably be at least 8.5 mm, for example.

The first tapered section of the channel forms the end of the wire inlet area. This is immediately followed by the wire guide area and extends to the front end of the wire nozzle. The conical taper is designed in the direction of the wire passage, i.e. the diameter of the channel tapers conically to a diameter in the wire guide area.

In an embodiment with particularly good positioning accuracy of the wire, the wire guide area has a length between 50 percent and 75 percent of the total length of the channel. This configuration enables precise positioning of the wire without significantly impairing the service life of the nozzle.

The wire guide area is used to guide and position the wire. In order to enable sufficiently precise positioning of the wire, the cross section of the channel in the wire guide area is smaller than at the inlet opening, e.g. the diameter of the channel is a maximum of 1.5 times or a maximum of 1.2 times the diameter of the wire to be guided . In the wire guide area, the channel has a substantially constant cross section, i.e. the diameter of the channel changes in the wire guide area by, for example, less than 30% or less than 20%. In addition, however, the channel at the outlet opening can have a funnel-shaped cross-sectional expansion, for example due to deburring.

In one embodiment, the first conically tapered section adjoins the inlet opening, i.e. the first conically tapered section extends over the entire wire inlet area of the channel, i.e. from the wire guide area to the inlet opening. As a result, the channel wall forms the shape of an insertion funnel, which enables the wire to be fed in with particularly low abrasion. It is also possible to create such a wire inlet area in just one step.

In a further embodiment, the channel further has at least a second conically tapered section, which is arranged in front of the first conically tapered section in the direction of wire passage, and at least a first cylindrical section which connects the first conically tapered section with the second conically tapered section. The taper of the channel cross section in the wire inlet area therefore takes place in at least two sections, between which a cylindrical channel section is formed. The resulting abrasion can easily collect in the cylindrical channel section without impairing the functionality of the nozzle. For this purpose, the first cylindrical section can preferably, for example a length of at least 2.5 mm. Alternatively, the first cylindrical section can also have a length of at least 3 mm.

By arranging a second cylindrical section in front of and adjacent to the second tapered section, a further channel section is provided for collecting debris.

In further embodiments, a plurality of conically tapered and cylindrical sections can be provided alternately in the wire inlet area, for example three or four conically tapered or cylindrical sections each.

The wire nozzle is preferably formed in one piece. This reduces production costs and assembly time compared to a multi-part wire nozzle.

The channel wall of the wire nozzle is inclined in the first conically tapered section at an angle α relative to the longitudinal axis of the wire nozzle. In one embodiment, the angle α is preferably in the range of 6 to 25 degrees and can, for example, be in the range of 6 to 20 degrees or 6 to 15 degrees. By developing the conical taper in this angular range, the abrasion of the wire can be further reduced and at the same time the removal of the abrasion from the place of origin can be ensured.

In a particularly advantageous embodiment, the wire nozzle has a first and a second conically tapered section and a first and second cylindrical section - as described above - in the wire inlet area, the channel wall in the area of the first conically tapered section being at an angle in the range of 15 degrees is inclined up to 25 degrees relative to the longitudinal axis and the wire guide section has a length in the range of 16 mm to 21 mm. In this embodiment, it was surprisingly possible to achieve an unexpectedly large extension of the service life of the wire nozzle by a factor of 3.6.

The wire is guided particularly well if the wire guide section has a length of at least 16 mm.

In one embodiment, the channel, viewed in the direction of wire passage, has a minimum diameter at the end of the first conically tapered section and the diameter of the channel behind the first conically tapered section increases along the longitudinal axis in the direction of wire passage. The channel therefore has the minimum diameter at the boundary between the wire inlet area and the wire guide area. For example, the cross section of the channel in the wire guide area widens conically along the wire guide direction. In this configuration, the abrasion occurs mainly at the beginning of the wire guide area. Thus, less abrasion enters the wire guide area, but instead collects in the conical tapered section immediately in front of the wire guide area.

With regard to the method, the object of the invention is achieved in that the additional wire is guided through a wire nozzle described above and fed to a joining point. The process benefits from the technical effects and advantages of the device, including the reduced abrasion of the wire with simultaneous good positioning, as well as the reduced costs due to a wire nozzle that is inexpensive to produce and replace.

The wire nozzle according to the invention can be used for laser welding and soldering processes, especially with cold wire feeding. The wire nozzle is particularly suitable for laser joining of steel materials or aluminum, for example. The wire nozzle according to the invention is designed to be used in laser joining processes with tactile wire guidance.

In one embodiment, a process gas is passed through the channel of the wire nozzle during the joining process. The process gas can be a protective gas, such as argon or helium, or mixed gases with, for example, argon and/or helium content. Alternatively, air can also be passed through the nozzle channel. By passing wire and process gas through the channel at the same time, abrasion is further reduced because the process gas lies like an air cushion between the channel wall and the wire. In addition, the resulting abrasion is blown out of the channel together with the process gas. Furthermore, vapors and splashes generated during the joining process are kept away from the nozzle.

The characteristics, features and advantages of this invention described above and the manner in which they are achieved will be more clearly and clearly understood in connection with the following description of the exemplary embodiments. If the term “can” is used in this application, it refers to both the technical possibility and the actual technical implementation.

• 1: einen Längsschnitt durch eine Drahtdüse gemäß einem ersten Ausführungsbeispiel der vorliegenden Erfindung
• 2: eine Rückansicht der Drahtdüse entlang der Längsachse gemäß dem ersten Ausführungsbeispiel
• 3: einen Längsschnitt durch eine Drahtdüse gemäß einem zweiten Ausführungsbeispiel der vorliegenden Erfindung

Examples of embodiments are explained below using the accompanying drawings. Show in it:

• 1 : a longitudinal section through a wire nozzle according to a first embodiment of the present invention
• 2 : a rear view of the wire nozzle along the longitudinal axis according to the first exemplary embodiment
• 3 : a longitudinal section through a wire nozzle according to a second embodiment of the present invention

1 shows a sectional view of a wire nozzle 10 according to a first embodiment of the present invention. A channel 100 is formed in a nozzle body 12 along a longitudinal axis 14 of the wire nozzle 10. The channel 100 extends from an inlet opening 110 at the rear end 16 of the nozzle body 12 to an outlet opening 120 at the front end 18 of the nozzle body 12. The channel 100 is delimited in the radial direction by a channel wall 130 and has a round cross section transversely to the longitudinal axis 14 , as in 2 is shown.

During operation, an additional wire is guided through the channel 100, entering the wire nozzle 10 at the inlet opening 110 and leaving it at the outlet opening 120. The direction of wire passage is indicated by an arrow 20. The wire is transported to the wire nozzle via a wire feed device (not shown). An external thread 22 is provided at the rear end 16 of the wire nozzle 10. This allows the wire nozzle 10 to be attached, for example, to a wire guide head or a wire feed device. The external thread is preferably a metric thread, e.g. an M6, M8 or M10 thread. For assembly, the wire nozzle 10 has two wrench surfaces 24 on the outer surface of the nozzle body 12. These wrench surfaces are flats in the outer profile of the wire nozzle and preferably run parallel to the longitudinal axis 14. The wrench surfaces 24 serve as attachment surfaces of a tool for mounting the wire nozzle in the wire guide head or on the wire feed device. The outer surface of the nozzle body 12 tapers conically towards the front end 18. This results in better gas guidance if a process gas is to be guided past the outer surface of the wire nozzle.

As in 1 shown, the channel 100 has a wire inlet area 140 and a wire guide area 150. In the wire inlet area 140, the channel 100 has a first conically tapered section 142, adjacent thereto a first cylindrical section 144, and adjacent thereto a second conically tapered section 146. A second cylindrical section 148 adjoins this.

The second cylindrical section 148 borders, for example, directly on the inlet opening 110. Alternatively, a (not shown) cross-section-expanding bevel of the channel wall can be provided between the cylindrical section 148 and the inlet opening 110, which is caused, for example, by deburring in terms of production technology. In the second cylindrical section 148, the channel 100 has a first diameter D1. The diameter of the channel 100 reduces in the second conically tapered section 146 to a second diameter D2 of the first cylindrical section 144. In the first conically tapered section 142, the diameter of the channel 100 reduces to a wire guide diameter D3. The wire guide diameter D3 is preferably the smallest diameter of the channel 100 of the wire nozzle 10.

Viewed in the wire guide direction, the wire guide section 150 of the channel 100, which extends to the outlet opening 120, is directly adjacent to the first conically tapered section 142. The wire guide section 150 has the wire guide diameter D3 adjacent to the first tapered section 142. The first conically tapered section 142 thus reduces the diameter of the channel 100 to the diameter intended for wire guidance. The wire guide section 150 can have the wire guide diameter D3 over its entire length. In this case, the channel 100 in the wire guide section 150 is cylindrical. Alternatively, the diameter of the channel 100 in the wire guide section 150 can be as shown in 1 shown, increase along the wire guide direction from the wire guide diameter D3 to a larger diameter D4 at the outlet opening 120. In this case, the diameter in the wire guide section 150 changes, for example, continuously over the entire wire guide section, ie without a sudden change in diameter. Alternatively, the channel wall 130 in the wire guide section 150 can preferably be conical. At the outlet opening 120, an additional cross-section-expanding bevel of the channel wall (not shown) can be provided, which is caused, for example, by deburring in terms of production technology.

The dimensions of the wire nozzle 10 depend on the wire diameters used and system requirements and can vary accordingly.

The wire inlet area 140 can, for example, extend over at least 30 percent (%) of the total length L of the channel 100, or, for example, over at least 35% or at least 40% of the total channel length. In addition, the wire inlet area 140 can extend, for example, over a maximum of 50% of the total channel length L. The length of the Wire inlet area can preferably be at least 8.5 mm, for example.

Accordingly, the wire guide area can extend over at least 50% of the total channel length L. Preferably, the wire guide area has, for example, a length L2 of at least 16 mm, alternatively, the wire guide area can also, for example, have a length in the range of 16 mm to 21 mm.

In the first conically tapered section 142 adjacent to the wire guide area 150, the channel wall runs at an angle α relative to the longitudinal axis 14 of the wire nozzle 10. The angle α is therefore a measure of the taper of the diameter - the smaller α is, the flatter the inclination of the first conically tapered section 142 towards the longitudinal axis 14. The angle α in the first conically tapered section 142 can, for example, have a value in the range of 6 degrees to 25 degrees. For example, the angle α can also have a value in the range from 6 degrees to 20 degrees or 6 degrees to 15 degrees.

The first cylindrical portion 144 can preferably extend by a distance L1 along the longitudinal axis 14, where L1 can have a value in the range of 2.1 mm to 5 mm or 3 mm to 5 mm, for example. Alternatively, L1 can also be greater than 5 mm.

For example, the wire nozzle can have the following dimensions: The length L of the channel 100 or the wire nozzle 10 can be, for example, 20 mm to 32 mm. The first diameter D1 can be, for example, 3.5 mm to 5 mm, the second diameter D2, for example, 1.6 mm to 3 mm, the wire guide diameter D3, for example, 0.9 mm to 1.6 mm and the fourth diameter D4, for example, 1.0 up to 1.7 mm. These diameters are particularly suitable for additional wires with a diameter of 0.8 mm to 1.4 mm. In a preferred embodiment, a wire nozzle designed for a wire diameter of 1.2 mm has the following dimensions: L=28 mm, L1=3 mm, D1=4.3 mm, D2=2 mm, D3=1, 3 mm, D4=1.5 mm, each with a manufacturing tolerance of +/- 0.5 mm and α=19 degrees +/-1 degrees.

However, alternatively, wires with other diameters can also be used and/or other dimensions of the wire nozzle can be provided.

2 shows a top view of the wire nozzle 10 according to the first exemplary embodiment. Here it can be clearly seen that the channel 100 with the first and second conically tapered sections 142 and 146, the first and second cylindrical sections 144 and 148 and the wire guide area 150 is arranged concentrically around the longitudinal axis 14 of the wire nozzle 10.

3 shows a sectional view of a wire nozzle 10A according to a second embodiment of the present invention. The wire nozzle 10A of the second embodiment differs only in the design of the channel 100A from the wire nozzle 10 according to the first embodiment. In this respect, the same reference numerals are used for the same parts or sections as in 1 The statements made there also apply to the 3 shown identical parts or sections, which is why a repeated description is omitted.

In contrast to that in 1 In the exemplary embodiment shown, the channel 100A according to the second exemplary embodiment has only one conically tapered section 142A and only one cylindrical section 144A in the wire inlet area 140A.

The cylindrical section 144A borders directly on the inlet opening 110, for example. Alternatively, an additional cross-section-expanding bevel of the channel wall (not shown) can be provided between the cylindrical section 144A and the inlet opening 110, which is caused, for example, by deburring in terms of production technology. In the cylindrical section 144A, the channel 100A has the first diameter D1. The following applies to this diameter 1 statements made. The diameter of the channel 100A reduces to the wire guide diameter D3 in the tapered section 142A. The wire guide diameter D3 is preferably the smallest diameter of the channel 100A of the wire nozzle 10A.

Viewed in the wire guide direction 20, the wire guide section 150 of the channel 100A is directly adjacent to the conically tapered section 142A.

The wire entry area 140A may extend over at least 30 percent (%) of the total length L of the channel 100A, or, for example, over at least 35% or at least 40% of the total channel length. In addition, the wire inlet area 140A can extend, for example, over a maximum of 50% of the total channel length L. The length of the wire inlet area can preferably be at least 8.5 mm, for example. Accordingly, the wire guide area 150 can extend over at least 50% of the total channel length L or too 1 have the dimensions explained.

In the conically tapered section 142A, the channel wall runs, as for the first outlet example described, inclined at an angle α to the longitudinal axis.

The cylindrical portion 146A may preferably extend a distance L1 along the longitudinal axis 14, where L1 may, for example, have a value in the range of 2.5 mm to 5 mm.

In alternative exemplary embodiments, not shown, the channel can also have more than two conically tapered sections in the wire inlet area, for example three or four sections, each of which is connected to one another by a cylindrical section. Alternatively, the wire inlet area can also consist of a conically tapered section, i.e. the wire inlet area can be designed without a cylindrical section.

The wire nozzles 10 and 10A can be formed from a solid metal body, for example by machining manufacturing processes. For example, the outer contour of the wire nozzle can be shaped using turning and milling processes. The channel can be formed, for example, using several holes. Alternatively, the wire nozzles can also be made from plastics or ceramic materials, for example ceramic composite materials. Other shaping manufacturing processes, such as injection molding, can also be used.

Reference symbol list

10, 10A

Wire nozzle

12

Nozzle body

14

Longitudinal axis

16

rear end

18

front end

20

Wire feed direction

22

External thread

24

key surface

100, 100A

channel

110

Entry opening

120

Outlet opening

130

Canal wall

140, 140A

Wire inlet area

142, 142A, 146

conically tapered section

144, 144A, 148

cylindrical section

150

Wire guide area

A

angle

L, L1, L2

length

D1, D2, D3, D4

diameter

Claims (12)

Wire nozzle, set up for feeding a filler wire in a laser joining process with tactile wire guidance, with: - a nozzle body (12) with a longitudinal axis (14), - a channel (100; 100A) which is formed in the nozzle body (12) along the longitudinal axis (14), - wherein the channel (100; 100A) has at least a first conically tapered section (142; 142A) in the direction of a wire passage (20), which ends in a central region of the channel (100; 100A), - wherein the channel (100; 100A) has a wire guide area (150) which is arranged behind the first conically tapered area (142; 142A) in the direction of wire passage (20). wire nozzle Patent claim 1 , wherein the first conically tapered section (142A) adjoins an inlet opening (110) of the channel (100A) at a rear end (16) of the nozzle body (12). wire nozzle Patent claim 1 , wherein the channel (100) further comprises: - at least a second conically tapered section (146), which is arranged in front of the first conically tapered section (142) in the direction of wire passage (20) and - at least a first cylindrical section (144), which connects the first tapered section (142) to the second tapered section (146). Wire nozzle after Patent claim 3 , wherein the channel (100) has a second cylindrical portion (148) which is arranged in front of the second conically tapered portion (146) in the wire passage direction (20) and adjoins the latter. wire nozzle Patent claim 3 or 4 , wherein the first cylindrical section (144) has a length (L1) of at least 2.5 mm. Wire nozzle according to one of the preceding claims, wherein the wire nozzle (10; 10A) is formed in one piece. Wire nozzle according to one of the preceding claims, wherein a channel wall (130) of the channel (100; 100A) in the first conically tapered section (142; 142A) is at an angle (α) in the range of 6 degrees to 25 degrees relative to the longitudinal axis (14 ) of the wire nozzle (10; 10A) is inclined. Wire nozzle according to one of the preceding claims, wherein the wire guide area (150) has a length between 50 percent and 75 percent of a total length (L) of the channel (100; 100A). wire nozzle Patent claim 8 , wherein the wire guide area (150) has a length of at least 16 mm. Wire nozzle according to one of the preceding claims, wherein the channel (100; 100A) at the end of the first tapered section (142; 142A) has a minimum diameter (D3) and the diameter of the channel (100; 100A) tapers behind the first Section (142; 142A) enlarged along the longitudinal axis (14) in the direction of wire passage (20). Method for laser joining with additional wire with tactile wire guidance, wherein an additional wire is guided through a wire nozzle (10; 10A) according to one of the preceding claims and fed to a joining point. Procedure according to Claim 11 , wherein a process gas is passed through the channel (100; 100A) of the wire nozzle (10; 10A).

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