Device for cleaning a welding wire

Abstract

Device (12) for cleaning a welding wire (14) by separating magnetic particles from the welding wire (14), with - a housing (10) whose housing wall (32, 34) has a housing inlet (24) and a housing outlet (16) for guiding the welding wire (14) through, and - at least one magnetic unit (38) arranged in the housing (10) for depositing magnetic particles, characterized in that a sensor (40) for detecting deposited magnetic particles on the magnetic unit (38) is arranged in the housing (10).

Description

[0001] The invention relates to a device for cleaning a welding wire.

[0002] Welding robots often feed welding wire as a continuous wire. During the conveying process, unwanted foreign matter such as particles or dust is often transported along with the welding wire to a wire feed station or to the welding point.

[0003] In this context, JP H05-177 356 A discloses a welding wire cleaning device comprising a substantially cylindrical demagnetization coil through which a welding wire to be cleaned is passed. The demagnetization achieved by appropriately applying current to the coil allows the separation of ferromagnetic particles from the welding wire, whereby the separated particles can be blown out of the coil area by means of a compressed air jet.

[0004] Furthermore, US 5 981 904 A discloses an arrangement for cleaning a welding wire, in which an electrically generated field is set in rotary motion by means of a magnetic field for the circumferential removal of contaminants adhering to the welding wire.

[0005] The object of the present invention is to clean the welding wire as efficiently as possible while it is being conveyed to a welding point.

[0006] This object is achieved according to the features of independent patent claims 1 and 11.

[0007] According to patent claim 1, a device for cleaning a welding wire is provided. The cleaning involves separating or capturing magnetic particles or magnetic dust originating from the welding wire. The device can therefore also be referred to as a separation device. The device has a housing, the housing wall of which has a housing inlet and a housing outlet for the passage of the welding wire. At least one magnet unit for separating or capturing magnetic particles is arranged in the housing. Each magnet unit contains at least one magnet. The at least one magnet unit attracts magnetic particles from the welding wire, which is guided into the housing inlet and out of the housing through the housing outlet, passing the at least one magnet unit.In addition, the at least one magnet unit can attract magnetic particles present in the area of ​​the housing inlet, e.g., inside a wire guide connected to the housing inlet. Magnetic abrasion from the welding wire may also be present there.

[0008] Furthermore, a sensor or sensor unit for detecting separated or captured magnetic particles is arranged in the housing. This sensor system offers a cost-effective option for integrated monitoring of the device's condition with respect to a measure (e.g., concentration, quantity, volume) of the magnetic particles captured by the magnetic unit. In the case of multiple magnetic units, each of the magnetic units can be assigned its own sensor.

[0009] Advantageously, a sensor signal from the sensor unit can be used to trigger a process for removing or disposing of the magnetic dust or magnetic particles captured by the magnetic unit. For example, a detected actual sensor signal is compared with a defined threshold value, and if the comparison result is appropriate (e.g., the threshold value is exceeded or exceeded), disposal of the magnetic particles captured or separated by the magnetic unit is triggered.

[0010] The device reduces the amount of foreign matter, particularly magnetic dust and particles, that reaches the weld point. For example, the wire feed unit and the conveyor rollers that feed or transport the welding wire to the weld point are significantly reduced or even eliminated from the buildup of metallic dust. This allows the welding wire to be fed more easily and at a constant speed. This promotes more consistent welding quality. Furthermore, the tensile force required to feed or advance the welding wire is reduced. Furthermore, fewer foreign matter enters the molten metal of the weld seam with the welding wire. Fewer foreign matter in the weld metal area results in fewer inclusions, cavities, and welding defects at the weld point. Accordingly, the quality of the welding process is significantly improved.

[0011] The housing can be made of a plastic. In particular, it is made at least partially of aluminum. It can be manufactured in one piece or assembled from several parts. The welding wire is preferably designed as a continuous wire.

[0012] The magnet unit contains at least one magnet, which is designed in particular as a permanent magnet.

[0013] The device comprises at least one magnet unit, preferably two magnet units. They can be distributed on the housing in such a way that the welding wire is flanked by a magnet unit at various positions along its sheath circumference.

[0014] To facilitate assembly and handling of the magnet unit, it preferably has a magnet support element that passes through a magnet connection opening in the housing wall. The magnet support element serves to secure the magnet unit and thus the at least one magnet of this magnet unit. The magnet support element is made of plastic, for example. Furthermore, the magnet support element has, in particular, a sleeve-like design that can surround or enclose the magnet(s) and thus protect them against any damage or other wear.

[0015] Preferably, the magnet carrier element has an external thread similar to a screw, which corresponds to an internal thread of the magnet connection opening. This supports stable positioning of the magnet unit in the housing.

[0016] In a preferred embodiment, the sensor system comprises a conductivity sensor for detecting or sensing an electrical conductivity. The conductivity sensor is particularly suitable because it can detect captured magnetic particles and, at the same time, its sensor signals are not influenced by the magnet unit itself. The sensor preferably contains two electrically conductive sensor wires, each of which is arranged with a wire section in the housing. These sensor wire sections flank an associated magnet unit at a suitable distance. This technically simple and space-saving design of the sensor system enables its use even in particularly small sizes or confined spaces in the housing of the device. Space-saving handling of the sensor system on the housing is also supported by the fact that evaluation electronics for evaluating the sensor signals can be arranged away from the measuring point in the housing, e.g.in a control cabinet.

[0017] To facilitate assembly, the sensor wire sections are preferably arranged or fixed to a sensor support element of the sensor system. The sensor support element passes through a sensor connection opening in the housing wall. The sensor support element is made of plastic, for example. Furthermore, the sensor support element has, in particular, a sleeve-like design, which can encompass or enclose a sensor wire section and thus protect it against any damage or other wear.

[0018] Preferably, the sensor support element has an external thread similar to a screw, which corresponds to an internal thread of the sensor connection opening. This supports stable positioning of the sensor in the housing.

[0019] The aforementioned process for removing or disposing of the magnetic dust or magnetic particles captured by the magnet unit is carried out in particular using compressed air. The housing wall preferably has at least one line connection opening for connecting a compressed air line to blow the captured magnetic particles away from the magnet unit. To easily dispose of the particles blown away in this way, the housing wall preferably has at least one discharge opening for discharging separated or captured magnetic particles from the housing. This allows for cleaning of the magnet units arranged in the housing when they become clogged with magnetic particles with minimal technical effort.

[0020] The aforementioned object is further achieved with an arrangement according to patent claim 11. This arrangement comprises a welding robot, a wire feed unit for transporting or feeding the welding wire (preferably designed as a continuous wire) to the welding robot, and a device for separating magnetic particles from the welding wire. The advantages mentioned in patent claim 1 apply equally to the entire arrangement.

[0021] The device is preferably arranged upstream of the wire feed unit in the transport direction of the welding wire. The device can thus be arranged or mounted directly upstream of the wire feed unit. Magnetic particles transported to the wire feed unit by the welding wire are therefore intercepted before entering the wire feed unit. Magnetic abrasion therefore prevents at least some of it from entering the wire feed unit in the first place. As already mentioned, this supports a stable welding process and a high-quality weld seam.

[0022] In a preferred embodiment, the housing inlet of the device is connected to a wire guide line. This allows for a mechanically simple "intermediate connection" of the device between a conventional wire feed unit and a wire guide line conventionally connected to this wire feed unit.

[0023] The device according to the invention is explained in more detail below with reference to the accompanying drawings. Components that are identical or comparable in terms of their function are designated by the same reference numerals. They show: Fig. 1 a first perspective view of a housing of the device, Fig. 2 a second perspective view of the housing according to Fig. 1, Fig. 3 a top view of the housing in the direction of view III according to Fig. 1, and Fig. 4 a schematic representation of an arrangement with a welding robot and a device according to the invention.

[0024] Fig. 1 shows a housing 10 of the Fig. 4 schematically illustrated device 12 for separating magnetic particles of a welding wire 14, which in Fig. 4 is designed as an endless wire. The housing 10 according to Fig. 1 has a housing outlet 16 for guiding the welding wire 14 out of the device 12 along a transport direction 18 to a wire feed unit 20 ( Fig. 4). Opposite the housing outlet 16 in the longitudinal direction or axial direction 22, the housing 10 has a housing inlet 24 for introducing the welding wire 14. The housing outlet 16 and the housing inlet 24 are arranged on the two axially opposite end faces 32, 34 of the housing 10. Together with a housing shell 28 arranged therebetween, they form a housing wall of the housing 10. This housing wall delimits a cavity 62 of the housing 10. The housing shell 28 has a plurality of through holes, some of which have different dimensions.

[0025] Among the aforementioned through-holes in the housing shell 28 are two magnet connection openings 30. Each magnet connection opening 30 serves to accommodate a magnet unit 38 and is flanked by two sensor connection openings 36 in the housing shell 28. The sensor connection openings 36 serve to accommodate a sensor in the form of a conductivity sensor 40. Furthermore, the housing shell 28 is perforated by several line connection openings 42 for the inlet of compressed air in order to blow compressed air into the cavity 62 of the housing to clean the magnet units 38 of any accumulated magnetic dust. In addition, the housing shell 28 is penetrated by several outlet openings 44. The magnetic particles collected on the magnet units 38 can be discharged from the housing 10 and disposed of by means of the compressed air blown into the cavity 62 of the housing 10. Furthermore, the housing shell 28 is penetrated by fixing holes 46.These fixing holes 46 can be used, in a manner not described in detail here, to fix specific elements to the housing 10 and / or to fix the housing 10 in a position.

[0026] In Fig. 3 clearly shows the arrangement of the various through-holes on the housing shell 28. Two magnet connection openings 30 are arranged along a circumferential direction 48 of the housing 10 at a circumferential angle of 90° to each other. Diametrically opposite each of the magnet connection openings 30 is a line connection opening 42 for the aforementioned compressed air inlet. A total of four outlet openings 44 penetrate the housing shell 28. They are evenly distributed in the circumferential direction 48, with one outlet opening 44 located between the two magnet connection openings 30.

[0027] The magnet unit 38 has a sleeve-like magnet carrier element 50 - preferably made of plastic - which comprises a magnet 52 and thereby carries ( Fig. 4). The magnet carrier element 50 has a merely indicated external thread 54 on its outer surface, which corresponds to an internal thread 56 of the magnet connection opening 30. Thus, the magnet carrier element 50 is screwed into the magnet connection opening 30 for simple and stable positioning of the magnet unit 38 on the housing 10.

[0028] The conductivity sensor 40 for sensing or detecting an electrical conductivity has two sensor wires 58 or electrical cables, each of which is arranged with a sensor wire section 60 in the cavity 62 of the housing 10 ( Fig. 4). The two sensor wire sections 60 are each enclosed by a sleeve-like sensor support element 64, preferably made of plastic, which has a merely indicated external thread 66. The external thread 66 corresponds to an internal thread 68 of the sensor connection opening 36. Thus, the sensor support elements 64 are screwed into the sensor connection openings 36 for simple and stable positioning of the conductivity sensor 40 on the housing 10.

[0029] In Fig.Figure 4 shows a schematic, not to scale, arrangement 70 comprising a welding robot 72, a wire feed unit 74 with wire feed rollers 76 transporting the welding wire 14, and a wire guide line 78. Along the transport direction 18, the separating device 12 is mechanically interposed between the wire feed unit 74 and the wire guide line 78. The wire feed unit 74 can be mounted on the welding robot 72 in a conventional manner. The wire guide line 78 is connected to the housing inlet 24 and is partially surrounded by a spring element 80 as an anti-kink device. By mechanically interposing the separating device 12 in a conventional arrangement for robot-assisted welding, the welding wire 14 can be cleaned cost-effectively and efficiently, and consequently the welding quality and the welding process can be improved using simple technical means.

[0030] The welding wire 14 is transported in the transport direction 18 toward the welding robot 72 to be used in the usual way for a robot-assisted welding process. During this transport, foreign matter, in particular magnetic dust, can pass through the welding wire 14 into the wire guide line 78 and into the wire feed unit 74. This is avoided with the arrangement 70 in that the separator 12 magnetically attracts magnetic dust or particles from the welding wire 14 and from the wire guide line 78. When a magnet unit 38 is clogged with a certain amount of magnetic dust, the conductivity sensor 40 reacts because its sensor wire sections 60 are in electrical contact with the magnetic dust. The sensor signals of the conductivity sensor 40 are processed by a control unit 82. Depending on the sensor signals, the control unit 82 controls a valve unit 84 (e.g.Solenoid valve) which is connected to a compressed air line 86. Depending on the control unit 82, compressed air (e.g., from a control system of the welding robot) is fed via the compressed air line 86 into one or more line connection openings 42 and thus into the cavity 62 of the housing 10, and from there blown out again. In this way, the magnet units 38 can be automatically cleaned of the collected magnetic dust, as already explained.

Claims

[1] Device (12) for cleaning a welding wire (14) by separating magnetic particles from the welding wire (14), with - a housing (10), the housing wall (32, 34) of which has a housing inlet (24) and a housing outlet (16) for passing the welding wire (14), and - at least one magnet unit (38) arranged in the housing (10) for separating magnetic particles, characterized by that a sensor (40) for detecting separated magnetic particles on the magnet unit (38) is arranged in the housing (10). [2] Device according to claim 1, characterized by that the magnet unit (38) has a magnet carrier element (50) for fixing at least one magnet (52), wherein the magnet carrier element (50) passes through a magnet connection opening (30) in the housing wall (28). [3] Device according to claim 1 or 2, characterized bythat the magnet carrier element (50) has an external thread (54) which corresponds to an internal thread (56) of the magnet connection opening (30). [4] Device according to one of the preceding claims, characterized by that the sensor system has a conductivity sensor (40) for sensing an electrical conductivity. [5] Device according to one of the preceding claims, characterized by that the conductivity sensor (40) has two sensor wires (58), each of which is arranged with a sensor wire section (60) in the housing (10). [6] Device according to one of the preceding claims, characterized by that the conductivity sensor (40) has two sensor carrier elements (64) for fixing a respective sensor wire section (60), wherein the sensor carrier elements (64) each pass through a sensor connection opening (36) in the housing wall (28). [7] Device according to one of the preceding claims, characterized bythat the sensor carrier element (64) has an external thread (66) which corresponds to an internal thread (68) of the sensor connection opening (36). [8] Device according to one of the preceding claims, characterized by that the housing wall (28) has at least one line connection opening (42) for connecting a compressed air line (86). [9] Device according to one of the preceding claims, characterized by that the housing wall (28) has at least one discharge opening (44) for discharging separated magnetic particles. [10] Arrangement (70) with a welding robot (72), a wire feed unit (74) for transporting the welding wire (14) to the welding robot (72) and with a device (12) according to one of the preceding claims. [11] Arrangement according to claim 10, characterized by that the device (12) is arranged in front of the wire feed unit (74) in the transport direction (18) of the welding wire (14). [12] Arrangement according to claim 10 or 11, characterized by that the housing input (24) of the device (12) is connected to a wire guide line (78).

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