Laser welding device and method for operating a laser welding device

Abstract

The invention provides a laser welding device (100), comprising: a laser hand welding gun (110; 210) with an electrically conductive tip (111) and an electrically insulating tip housing (119), wherein the tip housing (119) is made of a glass and / or ceramic material, can be mounted on the laser hand welding gun (110; 210), and insulates the tip (111) except for a contact section (118) of the tip (111) for contact of the tip (111) with a workpiece (1); a current clamp (120) for clamping to the workpiece to be welded; and a safety device (140) which is designed to check safety conditions and to only allow welding with the laser hand welding gun (110; 210) if all safety conditions are met; wherein the safety conditions include at least that a closed circuit must be present between the current terminal (120) and the contact section (118) of the tip (111) of the laser hand welding gun (110; 210) or between the current terminal (120) and a welding filler wire (50) held by any filler wire holder (250) of the laser hand welding gun (110; 210).

Description

Field of the invention

[0001] The invention relates to a laser welding device with increased safety in use and a method for operating a laser welding device. Technical background

[0002] Manual laser welding is a versatile welding technique. To ensure the workpiece—and any filler wire—is sufficiently melted, the laser beam emitted by the manual laser welding gun must have sufficient power. This raises safety concerns, as the laser beam could potentially be directed at other targets or even people.

[0003] A fuse known in the state of the art is in the Fig. 6 to 8. They show a workpiece 1 that is to be welded with a laser welding gun 2. The laser light for the welding laser is generated in a laser light source 3 and guided to the laser welding gun 2 by means of a light guide 6.

[0004] To supposedly ensure that the laser beam can only be directed onto the workpiece 1, a first power line 7, which is electrically connected to the electrically conductive tip 5 of the laser welding gun, and a second power line 8, which is connected to a power terminal 4, are provided. The first and second power lines 7, 8 are both connected to the laser light source 3, which is configured to check whether a closed circuit exists between the power terminal 4 and the tip.

[0005] This is intended to ensure proper use in accordance with Fig. 7 must be ensured: the current clamp 4 should be clamped to the workpiece 1. If the tip 5 is now pressed against the workpiece 1 for laser manual welding, the circuit (see the arrows in Fig. 7) is closed, and the laser light source 3 generates the welding laser or releases it for welding. However, if the tip is not pressed against the workpiece, and the laser beam is thus potentially freely accessible, the circuit is not closed and welding is not enabled.

[0006] An example of such a security measure is described in CN 214291401 U.

[0007] However, the security measure mentioned, which is known in the state of the art, can be undesirably circumvented: as in Fig. As shown in Figure 8, the current terminal 4 could be electrically connected directly to the tip 5. Thus, the circuit would always be closed from the perspective of the laser light source 3, and the laser beam 9 could - as in Fig. 8 - be freely accessible, which may pose a security risk.

[0008] US 2023 / 0 158 601 A1 and US 2003 / 0 213 786 A1 are also known from the prior art. US 2023 / 0 158 601 A1 discloses a laser welding system with a handheld laser welding torch comprising a nozzle with an electrically insulating outer surface, a pressure sensor that measures the pressure exerted on the nozzle, and a proximity sensor. Based on the measured values ​​of the two sensors, signals are transmitted to a control unit, which activates a laser light for welding.

[0009] US 2003 / 0 213 786 A1 describes a portable, handheld, powder-fed laser welding torch comprising a housing, a handle, and a nozzle assembly. The nozzle has a central opening through which a laser light can be directed, and a cover configured to allow gas to flow between the nozzle and the cover. The laser welding torch further includes a proximity sensor protruding from the nozzle to detect the presence of a workpiece to be welded. When the proximity sensor contacts the workpiece, the laser light is activated for welding. Summary of the invention

[0010] In view of the foregoing, it is therefore an object of the present invention to provide a laser welding device with improved safety, as well as to provide a safer method for operating a laser welding device.

[0011] This object is achieved according to the invention by the features of the independent patent claims.

[0012] The invention thus provides a laser welding device comprising: a laser welding gun with an electrically conductive tip and an electrically insulating tip housing, wherein the tip housing consists at least partially of a glass and / or ceramic material, wherein the tip housing is mounted or mountable on the laser hand welding gun, and, when mounted, the tip housing insulates the tip except for a contact portion for contact of the tip with a workpiece to be welded; a current clamp for clamping to the workpiece to be welded; and a safety device designed to check at least one safety condition and to only authorise welding with the laser welding gun if all safety conditions are met; wherein the at least one safety condition comprises at least a first safety condition according to which a closed circuit must be present between the current clamp and the contact portion of the tip of the laser welding gun or the current clamp and a welding filler wire held by any (i.e., optional) filler wire holder of the laser welding gun, The tip housing is designed to be exchangeable and wherein the at least one safety condition comprises at least one additional safety condition which checks whether the replaceable tip housing is actually correctly mounted on the laser welding gun.

[0013] The contact section, which, according to its designation, is intended to come into contact with the workpiece to be welded, is preferably so small and / or shaped (e.g., curved) that it is impossible to connect a current clamp. Particularly preferably, the contact section is just large enough to enable manual laser welding, and during welding, it can only be brought into contact with the workpiece and is inaccessible from the outside. In other words, the tip housing shields the tip so that it can only come into contact with the workpiece (at the contact section).

[0014] The security device may be implemented partly in hardware and partly in software. It may comprise a microprocessor or another type of digital processing unit, such as a central processing unit (CPU), a graphics processing unit (GPU), a field-programmable logic controller (FPGA), an application-specific integrated circuit (ASIC), and / or a combination thereof. The security device may also include a memory operatively coupled to the at least one processor unit, and a non-volatile memory operatively coupled to the at least one processor unit and the memory.

[0015] The laser welding gun can be designed with or without a filler wire holder.

[0016] The filler wire holder advantageously has a holder housing which encloses the elements of the filler wire holder which guide the filler wire in such a way that the filler wire can only be electrically contacted from the outside by contact with the workpiece to be welded. Analogously, the holder housing is electrically insulating and consists at least partially of a glass and / or ceramic material, for example of the same glass and / or ceramic material as the tip housing. In particular, any elements of the filler wire holder which are fixedly arranged with respect to the laser welding gun and which are in electrical contact with the filler wire can advantageously be enclosed by the holder housing in such a way that they can no longer be electrically contacted from the outside. The welding wire itself cannot be used for bridging because it is melted during laser welding and is constantly moving.

[0017] If the laser welding gun is designed without a filler wire holder, the first safety condition is that there must be a closed circuit between the current terminal and the contact section of the tip of the laser welding gun.

[0018] If the laser welding gun is designed with a filler wire holder (especially an integrated one), the first safety condition can be one of the following: - there must be a closed circuit between the current terminal and the contact section of the tip of the laser welding gun; - there must be a closed circuit between the current terminal and a welding filler wire held by a filler wire holder of the laser welding gun; - there must be closed circuits both between the current terminal and the contact section of the tip of the laser welding gun, and between the current terminal and a welding filler wire held by a filler wire holder of the laser welding gun.

[0019] Further safety conditions are described below, each of which can be optionally added. The designation of the described safety conditions as "first safety condition", "second safety condition", and so on is intended only to distinguish them and does not imply that, for example, the "third safety condition" can only be provided if the "second safety condition" has also been provided beforehand, or anything similar. Rather, it is understood that for each specific embodiment of the laser welding device, a suitable selection of safety conditions can be made, regardless of their designation. Some safety conditions are listed without a specific designation, but this should not be interpreted as less preferred or less useful.The same applies to the numbering of visual safety criteria, limit switches, electrical contacts or other numbering of the type mentioned.

[0020] According to some preferred embodiments, variants, or refinements of embodiments, the tip housing consists of at least one glass and / or ceramic material. Glass and / or ceramic materials are not only electrically insulating but also highly heat-resistant and thus insensitive to the temperatures encountered during manual laser welding. The same advantageously also applies to the holder housing.

[0021] According to the invention, the tip housing is designed to be replaceable. The tip housing can become contaminated or damaged by welding spatter or other stresses; if it is designed to be replaceable, it can be replaced at any time. According to the invention, the at least one safety condition includes at least one additional safety condition that checks whether the replaceable tip housing is actually correctly mounted on the laser welding gun (i.e., such that the tip is enclosed in an insulating housing except for the contact section of the tip).

[0022] It is understood that, correspondingly and with the same advantages, the holder housing can also be designed to be interchangeable, and that the at least one safety condition can include at least one additional safety condition according to which the interchangeable holder housing must actually be correctly mounted on the additional wire holder.

[0023] According to some preferred embodiments, variants, or refinements of embodiments, the laser welding gun has at least one limit switch, which is necessarily actuated when the tip housing is correctly mounted on the laser welding gun. The at least one safety condition advantageously includes a second safety condition, according to which the at least one limit switch of the laser welding gun must be actuated. In this way, it is checked whether the tip housing is correctly mounted on the laser welding gun, i.e., for example, whether it actually encloses the tip in such a way that it can only be electrically contacted from the outside by contact with the workpiece to be welded.

[0024] Similarly, the support housing can also have at least one such limit switch, which is necessarily actuated when the support housing is correctly mounted on the additional wire support. The at least one safety condition advantageously includes a further safety condition according to which the at least one limit switch of the additional wire support must be actuated.

[0025] According to some preferred embodiments, variants, or refinements of embodiments, the laser welding gun further comprises a first electrical contact and a second electrical contact insulated therefrom (i.e., from the first electrical contact), which are configured and arranged such that the first electrical contact and the second electrical contact would be electrically connected by a mounted, electrically conductive tip housing. The at least one safety condition may include a third safety condition, according to which no electrical connection may exist between the first electrical contact and the second electrical contact.In this way, it is possible to check with simple means whether the intended electrically insulating tip housing has been - improperly - replaced by an electrically conductive tip housing, which could possibly allow direct contact between the current terminal and the tip of the laser welding gun, i.e., could allow improper circumvention of the first safety condition.

[0026] According to some preferred embodiments, variants, or refinements of embodiments, the first and / or second electrical contact is / are integrated into a respective limit switch of the at least one limit switch. This further simplifies the design of the laser welding gun. This results in, for example, the following variants: a) a first end contact with integrated first electrical contact, and a second electrical contact; b) a first end contact with an integrated first electrical contact and a second end contact with an integrated second electrical contact; c) one end contact (or several end contacts) and additionally a first and a second electrical contact.

[0027] It is understood that the same additional measures relating to the at least one end contact and / or to the electrical contacts, as well as the corresponding additional safety conditions, can alternatively or additionally also be arranged on the optionally provided additional wire holder and provided with respect to it.

[0028] According to some preferred embodiments, variants or refinements of embodiments, at least one limit switch is designed as an optical limit switch, as a capacitive limit switch, or as a mechanical limit switch, in particular a spring-loaded mechanical limit switch.

[0029] According to some preferred embodiments, variants, or refinements of embodiments, the safety device comprises an image input interface and an image processing module. The image input interface is configured to receive an image of the laser welding gun. The image processing module is configured to check whether the laser welding gun depicted in the received image meets at least one predefined visual safety criterion. The at least one safety condition may include a fourth safety condition, according to which the laser welding gun depicted in the received image must meet the at least one predefined visual safety criterion.

[0030] The image processing module can also be configured to check whether the filler wire holder of the laser welding gun in the received image meets at least one predetermined visual safety criterion.

[0031] According to some preferred embodiments, variants or refinements of embodiments, the at least one predetermined visual safety criterion comprises a first visual safety criterion according to which the laser welding gun must be visible with the tip housing correctly mounted on the laser welding gun and / or with the tip housing intact and / or with the tip housing unmodified and / or a second visual safety criterion according to which the filler wire holder must be visible with the holder housing correctly mounted on the filler wire holder and / or with the holder housing intact and / or with the holder housing unmodified.

[0032] According to some preferred embodiments, variants, or refinements of embodiments, the tip housing has a code element. The laser welding gun can comprise a code reading device configured to read the code element when the tip housing is correctly mounted on the laser welding gun (and preferably only then). The at least one safety condition can comprise a fifth safety condition, according to which the code element must be read by the code reading device. This can occur once (e.g., when starting laser generation), regularly, or continuously.

[0033] The code element may comprise an RFID code, and the code reading device may comprise an RFID reader. Alternatively or additionally, the code element may comprise an optical code, and the code reading device may comprise an optical reader.

[0034] According to some preferred embodiments, variants, or refinements of embodiments, the laser welding gun is configured such that the tip housing, when correctly mounted on the laser welding gun, opens a mechanical shutter, which releases a laser beam from the laser welding gun for laser welding. Alternatively or additionally, enabling welding by the safety device can also include opening the mechanical shutter, while if the safety device fails to enable the shutter, it remains closed.

[0035] According to some preferred embodiments, variants, or refinements of embodiments, the tip housing has a section made of a ceramic-coated metal, or is made entirely of a ceramic-coated metal. Such a tip housing is lighter and less expensive to manufacture than a tip housing made entirely of ceramic and / or glass material, but offers the same advantages of external electrical insulation and heat resistance during welding. In connection with the described variants with electrical contacts and the third safety condition, the coating must be designed to prevent electrical contact with the metal of the tip housing at at least one of the electrical contact positions.

[0036] According to some preferred embodiments, variants or refinements of embodiments, the safety device is integrated into the laser hand welding gun.

[0037] According to some preferred embodiments, variants, or refinements of embodiments, the laser welding device also comprises a laser light source configured to provide a laser beam for the laser welding gun. In this case, the safety device can be integrated into the laser light source. It is also possible for the safety device to be partially integrated into the laser welding gun and partially into the laser light source. It is also conceivable for the safety device to be partially or completely implemented elsewhere, for example, via a cloud computing platform. The safety device can, for example, comprise a machine learning model (MLM), for example as part of the image processing module.

[0038] According to some preferred embodiments, variants, or refinements of embodiments, the handheld laser welding gun comprises at least one temperature sensor configured to detect a temperature of the tip housing. In this case, the safety device can also be configured to generate and output control signals for shutting off the laser light source, or, if the laser welding device comprises a laser light source, to shut off the laser light source. Shutdown preferably occurs when (and as long as) a temperature measured by the temperature sensor exceeds a predetermined (or variable, for example, depending on a setting of the laser welding device) temperature threshold.

[0039] In this way, the risk of burns for a user of the laser welding device, in particular the handheld laser welding gun, can be prevented or prevented. Excessive heat generation (i.e., exceeding the temperature threshold) can occur, for example, due to incorrect operation, such as when welding a material with excessively high reflective properties, using an incorrect angle of attack, or using an unsuitable workpiece geometry. Furthermore, excessive heat generation can also be caused by an unsuitable (or impermissible, unsuitable, or similar) tip housing, for example, when using a tip housing made of plastic, which is impermissible.

[0040] If a temperature sensor is provided, the at least one safety condition may include the further safety condition that a temperature measured by the (at least one) temperature sensor must be less than or equal to the temperature threshold. A further safety condition may be that a temperature sensor must be present at all, i.e., that temperature signals from a temperature sensor are received at the safety device.

[0041] Another safety condition may be that the temperature must rise (at least briefly) after the start of a welding process. This allows plausibility to be verified that the received temperature signal actually originates from the laser welding gun, which is checked by the safety device. For this purpose, the safety device can be connected to the laser light source, a control system of the laser welding gun or the laser welding device, or something similar to receive information about when a welding process begins.

[0042] The temperature sensor is advantageously located either at the interface between the tip housing and the rest of the laser welding gun, or in or on the tip housing itself. If the tip housing is replaceable, a data interface can be provided between the tip housing and the rest of the laser welding gun, which is operable at least when the tip housing is correctly mounted on the laser welding gun.

[0043] If, as described above, the laser welding gun is equipped with a combination of code element and code reading unit, it can be provided that information which enables the setting of a suitable temperature threshold value (such as the temperature threshold value itself or information which enables the reading of the temperature threshold value from a database of the laser welding device) can be read out from the code element by the code reading unit.

[0044] Everything above about a temperature sensor arranged in or on the tip housing can - additionally or alternatively - also be provided for a holder housing of a filler wire holder.

[0045] According to a further aspect, the invention provides a method for operating a laser welding device, comprising the steps: Automatic testing of safety conditions by means of a safety device on the laser welding device; wherein the safety conditions comprise a first safety condition according to which a closed circuit must be present between a current terminal of the laser welding device and a contact portion of a tip of a laser welding gun or between the current terminal and a welding filler wire held by any filler wire holder of the laser welding gun; and wherein the safety conditions comprise at least a second safety condition, according to which an interchangeable tip housing with predetermined properties and in accordance with predetermined parameters must be mounted on the laser welding gun and / or an interchangeable holder housing with predetermined properties and in accordance with predetermined parameters must be mounted on the filler wire holder, if any; and Allow welding if all safety conditions are met and prevent (or prohibit) welding if at least one of the safety conditions is not met.

[0046] For this purpose, all variants described above and below with reference to the laser welding device according to the invention can be applied to the method according to the invention and vice versa.

[0047] In particular, the predetermined properties of the tip housing may include that the tip housing or the holder housing is electrically insulating, and in particular that it is partially or completely made of a glass and / or ceramic material, that it has a specific shape (at least in sections), and / or the like. Testing the predetermined properties may also include that the tip housing must be undamaged (i.e., intact, not broken, cracked, or the like) and / or unmodified (i.e., not drilled, ground, pierced, sawn off, or the like).

[0048] The predetermined parameters according to which the tip housing or the holder housing must be mounted may, for example, be that the tip housing or the holder housing is correctly mounted, for example in such a way that any limit switches provided for this purpose on the laser welding gun are actuated and / or in such a way that the tip is actually enclosed in an inaccessible manner except for the contact section.

[0049] Further preferred embodiments, variants and developments of embodiments emerge from the subclaims and from the description with reference to the figures.

[0050] Brief description of the figures. The invention is explained in more detail below using exemplary embodiments in the figures of the drawings. The partially schematic representation shows: Fig. 1 is a schematic diagram of a laser welding apparatus according to an embodiment of the present invention; Fig. 2 a schematic representation of a variant of the laser hand welding gun of the laser welding device from Fig. 1 in a condition in which welding is not permitted; Fig. 3 a schematic representation of the laser welding device from Fig. 2 in a state in which welding is permitted; Fig. 4 a schematic representation of a laser hand welding gun according to a variant of the laser welding device from Fig. 1 in a state in which welding is permitted; Fig. 5 is a schematic flowchart for explaining a method according to another embodiment of the present invention; Fig. 6 is a schematic diagram of the basic arrangement of a prior art laser welding apparatus; Fig. 7 a schematic representation of a permissible welding process with the laser welding device from Fig. 6; and Fig. 8 a schematic representation of an inadmissible welding process with the laser welding device from Fig. 6 and Fig. 7.

[0051] In all figures, identical or functionally identical elements and devices are provided with the same reference numerals, unless otherwise indicated. Detailed description of the characters

[0052] Fig. 1 shows a schematic representation of a laser welding apparatus 100 according to an embodiment of the present invention.

[0053] The laser welding device 100 comprises a laser welding gun 110 for manual laser welding. For this purpose, the laser welding gun 110 is advantageously designed with a handle 115.

[0054] The laser beam (or welding laser) is generated by a laser light source 130, which can be part of the laser welding device 100 or provided separately. The laser beam (or laser power) is guided to the laser handheld welding gun 110 via a light guide 131.

[0055] The laser beam is emitted by the laser welding gun 110 at a tip 111 of the laser welding gun 110, more precisely, at a contact section 118. The contact section 118 is so named because, during proper, intended use of the laser welding device 100, the contact section 118 should be in contact with the workpiece to be welded so that the laser beam only impinges on the workpiece and does not cause any hazard.

[0056] For this purpose, the tip 111, including the contact section 118, is electrically conductive (in particular made of a metal) and is electrically connected to a first power line 141. A second power line 142 is connected to a power terminal 120 of the laser welding device 100, which is configured and designed to be electrically connected to the workpiece to be welded, in particular to be clamped to the workpiece.

[0057] The laser welding device 100 also has a safety device 140, which is configured to check at least one safety condition and to only authorize welding with the laser welding gun 110 if all safety conditions are met. If the authorization is not given, i.e., if at least one safety condition is not met, the generation of the laser beam can be prevented, for example, or the laser beam itself can be mechanically blocked.

[0058] In the embodiment in Fig. 1, the safety device 140 is integrated into the laser light source 130. Alternatively, the safety device 140 can also be integrated into the laser welding gun 110, distributed across multiple devices, or arranged in a separate housing.

[0059] The at least one safety condition checked by the safety device 140 comprises at least a first safety condition, according to which a closed circuit must be present between the current terminal 120 and the contact section 118 of the tip 111 of the laser welding gun 110. For this purpose, the first power line 141 and the second power line 142 are advantageously electrically connected to the safety device 140, which can thus easily check for the presence of a closed circuit. If this is present, welding is enabled; if it is not present, the enable signal is not given. It can be provided that, if the enable signal is not given by the safety device 140, a mechanical trigger for the laser beam on the laser welding gun 110 is mechanically blocked, controlled by the safety device 140.

[0060] To prevent the simulation of a closed circuit without the involvement of the workpiece to be welded (by clamping the current clamp 120 directly to the tip 111), the invention provides an electrically insulating tip housing 119, which can be mounted (or is mounted) on the laser welding gun 110. The tip housing 119 consists at least partially (or entirely) of a glass and / or ceramic material. For example, it can be made of a ceramic-coated metal, although manufacturing entirely of glass and / or ceramic material is preferred.

[0061] The laser welding gun 110, in particular the tip 111 and the tip housing 119, are shaped such that, when the tip housing 119 is mounted on the laser welding gun 110, the tip housing 119 completely and electrically insulates the tip except for the contact section 118. Thus, although the current clamp 120 could be clamped to the tip housing 119, due to its electrically insulating properties, no closed circuit would be established between the tip 111 (or, analogously, the contact section 118, which is typically part of the integrally formed, metallic tip 111).

[0062] Even in this variant, the laser welding device 100 according to the invention represents a significant improvement in safety compared to conventional laser hand welding guns. Further measures can be taken in addition, for example as already explained above or explained in more detail below.

[0063] An optional possibility for further improving safety is to equip the safety device 140 with an image input interface 148 and an image processing module 149. The image input interface 148 is configured to receive at least one image (or video) of the laser welding gun 110, for example, via an app on a smartphone, a tablet, or a dedicated device.

[0064] The image processing module 149 is configured to check whether the laser welding gun 110 depicted in the received at least one image meets at least one predefined visual safety criterion. The at least one safety condition checked by the safety device 140 to enable welding can thus include a further safety condition according to which the laser welding gun depicted in the at least one received image must meet the at least one predefined visual safety criterion.

[0065] The at least one visual safety criterion may, for example, include a safety criterion that the laser welding gun 110 must be visible with the tip housing 119 correctly mounted on the laser welding gun 110.

[0066] The at least one visual safety criterion may, for example, also include a safety criterion according to which the tip housing 119 must be undamaged (ie intact).

[0067] The at least one visual safety criterion may, for example, also include a visual safety criterion requiring the tip housing 119 to be unmodified. This includes the tip housing 119 having predetermined properties, for example, the expected shape. In other words, this visual safety criterion may include the tip housing 119 being of a permitted (or expected, or approved) type, in particular a permitted (or expected, or approved) shape. Permitted shapes may, for example, in particular be those in which the tip housing encloses the tip 111 except for the contact section 118.

[0068] The at least one visual safety criterion may also include a visual safety criterion that the tip housing must enclose the tip 111 except for the contact portion 118.

[0069] Additional security conditions may be provided (ie, checked by the security device 140) that relate to the received images. The security device 140 may be configured to check properties of the received images as additional security conditions that must be met for the image to be considered admissible, ie, for the image to represent a valid basis for additional security conditions or visual security criteria based on the image.

[0070] For example, the at least one security condition may include a further security condition, according to which an image received by the image input interface must not exceed a predetermined age (e.g., one second, thirty seconds, five minutes, or the like). A further security condition may be that the image must be captured with a predetermined app installed on a smartphone or tablet, in particular using a camera of the smartphone or tablet without access to an image data storage device. Thus, an existing image captured in the past cannot be output as the current image; instead, a new, current image must be captured.

[0071] The laser welding device 100 can thus also provide such an application ("app"), which can be installed on a smartphone or tablet. The app can be a control app for the laser welding device 100, allowing various parameters to be adjusted using the app, for example. Alternatively, the app can also be installed on a dedicated remote control for the laser welding device 100, which preferably has a camera for capturing the required images.

[0072] The at least one image used to check the at least one visual safety criterion can be a sequence of images, in particular a video. Accordingly, everything stated with regard to the at least one image can also apply to such a video. One advantage of requiring a video and using it as the basis for the at least one visual safety criterion or further safety conditions is that to create an image, simply rephotograph a static image of a laser welding gun, whereas the same is more difficult to do for a video. In addition, a video also has the advantage that it can require a view of the laser welding gun from several different angles, or a three-dimensional check of the laser welding gun can be carried out.A visual safety criterion can thus include, for example, that the camera must be, or have been, moved around the laser welding gun once, or the like.

[0073] The at least one image can also be a live video stream. Preferably, the safety device can request the recording of the video stream in the app and, during the video stream, cause a visual change in the laser welding gun 110 (e.g., turning an LED on or off or the like) to verify that the laser welding gun 110 shown in the video stream is actually the laser welding gun 110 that is coupled to the safety device 140.

[0074] Fig. 2 shows a schematic representation of a variant of the laser hand welding gun 110 of the laser welding device from Fig. 1 in a state in which welding is not permitted (crossed-out lightning symbol in Fig. 2). In the variant shown, the tip housing 119 is designed to be replaceable, meaning it can be replaced with a similar tip housing 119, e.g., if the original tip housing 119 becomes damaged, dirty, or lost. A replaceable tip housing 119 means a removable tip housing 119 (as opposed to a non-replaceable tip housing 119 permanently mounted on the laser welding gun 110—which is also possible). This would potentially provide the possibility of overcoming safety measures by removing the tip housing 119 and clamping the current clamp 120 to the tip 111, which is then exposed again.

[0075] The laser welding gun 110 in Fig. 2 has, in order to counteract this, two limit switches 112-1, 112-2 (hereinafter also referred to collectively as 112-i), which are arranged and designed on the laser welding gun 110 in such a way that they are necessarily actuated when the tip housing 119 is correctly mounted on the laser welding gun 110.

[0076] Furthermore, third power lines 143 are provided, which carry electrical signals indicating information C2 indicating whether both limit switches 112-i are currently actuated. Accordingly, the safety device 140 can be configured to check, as a further safety condition, whether both limit switches 112-i are currently actuated and to enable welding (at most) if this is the case (a necessary condition). The third power lines 143 can accordingly be connected to the safety device 140.

[0077] In Fig. 2 shows the situation that the limit switches 112-i are not actuated, the corresponding safety condition is therefore not fulfilled, and welding is therefore not released by the safety device 140 (crossed-out lightning bolt top left in Fig. 2).

[0078] Fig. 3 shows the laser welding gun 110 from Fig. 2, with the difference that there the tip housing 119 is correctly mounted on the laser welding gun 110, the corresponding safety condition is therefore fulfilled, and thus welding is released by the safety device 140 (flash top left in Fig. 3).

[0079] At the Fig. 2 and Fig. In the variant of the laser welding gun 110 shown in Figure 3, both limit switches 112-1, 112-2 are also designed as electrical contacts 113-1, 113-2 (hereinafter also referred to collectively as 113-i), each of which is contacted by a fourth power line 144. The laser welding gun 110 is designed such that the two electrical contacts 113-i are electrically insulated from one another and remain electrically insulated from one another when a tip housing 119 according to the invention is correctly mounted on the laser welding gun 110.

[0080] The laser hand welding gun 110 designed in this way counteracts the further circumvention possibility that instead of the tip housing 119 according to the invention, an electrically conductive tip housing is mounted, which actuates the limit switches 112-i and electrically contacts the tip 111, so that the current terminal could in turn be clamped to the electrically conductive tip housing 119 to deceive the safety device 140.

[0081] To prevent this, the safety device 140 can be configured to check, in a further safety condition, whether the electrical contacts 113-1, 113-2 are electrically isolated from one another. If this is not the case, it means that an electrically conductive tip housing has been used, which is undesirable. Accordingly, the safety device 140 is configured to enable welding only when the electrical contacts 113-i are electrically insulated from one another, i.e., are not electrically connected to one another. For example, the fourth power lines 144 can be connected to the safety device 140, and the safety device 140 can check whether a closed circuit exists via the fourth power lines 144. In this way, the fourth power lines 144 can indicate information C3 as to whether the two electrical contacts 113-1, 113-2 are electrically connected to one another.

[0082] Although in Fig. 2 and Fig. 3, the electrical contacts 113-i are shown as integrated into the limit switches 112-i, it is understood that the limit switches 112-i and the electrical contacts 113-i can also be designed separately from one another. Likewise, more than two limit switches 112-i and / or electrical contacts 113-i can be provided.

[0083] As an additional safety measure to determine that an approved tip housing 119 according to the invention is mounted on the laser welding gun 110, the tip housing 119 can have a code element, and the laser welding gun 110 can include an associated code reading device configured to read the code element when the tip housing is correctly mounted on the laser welding gun. The at least one safety condition checked by the safety device 140 can include a further safety condition according to which the code element must be read by the code reading device.

[0084] For example, the code element can comprise an RFID code (RFID stands for "radio frequency identification"), and the code reading device can comprise an RFID reader. Alternatively or additionally, the code element can comprise an optical code, and the code reading device can comprise an optical reader. Other possibilities are also conceivable.

[0085] The code element can contain an activation code, which is checked by the code reading device or the security device 140 to determine whether it is a valid activation code. Welding is only permitted if the activation code is valid. The code element can also contain a specific identification code (e.g., an individual identification code such as a serial number) of the tip housing 119, which is checked by the code reading device or the security device 140 to determine whether it is a valid identification code. The validity of the identification code can be verified, for example, using symmetric or asymmetric cryptographic decoding methods and / or methods for verifying the authenticity of a signature.

[0086] Alternatively or additionally, the safety device 140 can also have access to a database of valid identification codes and use this database to distinguish between valid and invalid identification codes. It is also possible for the safety device 140 to receive both a device identification code of the laser welding gun 110 (e.g., via a data interface between the laser welding gun 110 and the safety device 140 or laser light source 130) and the identification code of the tip housing 119 read by the code reading device. The database to which the safety device 140 has access (e.g., an online database to which the safety device 140 has access via the Internet) can contain information about which combinations of identification codes are valid.

[0087] Fig. 4 shows a further laser hand welding gun 210 according to a further variant, which is also connected to the laser welding device 100 from Fig. 1 can be used. In contrast to the laser welding gun 110, the handheld laser welding gun 210 is additionally equipped with a filler wire holder 250, by means of which a welding filler wire 50 can be held and optionally also fed. Such filler wires can, on the one hand, provide additional material to the weld (e.g., for filling a fillet weld) and, on the other hand, also contain useful additional chemical elements that result in an improved chemical composition of the weld.

[0088] The basic test of the safety condition as to whether a closed circuit exists between the current terminal 120 and the tip 111 can thus be supplemented or replaced in the laser welding gun 210 by the test of the safety condition as to whether a closed circuit exists between the current terminal 120 and the welding filler wire 50.

[0089] As in Fig. 4, additional safety conditions can also be linked to conditions of the filler wire holder 250, and the filler wire holder 250 can accordingly also be provided with additional safety measures, as already described above with reference to the laser welding gun 110.

[0090] In this variant, electrical elements permanently connected to the laser welding gun 210 (i.e., those to which the current clamp 120 could potentially be clamped to undesirably bridge the circuit with the workpiece) are enclosed by a holder housing 259, i.e., shielded in such a way that the current clamp 120 cannot be clamped to it. The holder housing 259 can be made of the same material(s) as the tip housing 119, but is in any case electrically insulating and comprises a glass and / or ceramic material.

[0091] In particular, the holder housing 259 can also be designed to be exchangeable, and corresponding limit switches 252-1, 252-2 (hereinafter also referred to collectively as 252-i) and / or electrical contacts 253-1, 253-2 (hereinafter also referred to collectively as 253-i) can be provided in the additional wire holder 250, with some or all of them - as in Fig. 4 - the electrical contacts 253-i can also be integrated into a respective limit switch 252-i.

[0092] Accordingly, fifth power lines 245 can be connected to the electrical contacts 253-i and to the safety device 140, and the safety device 140 can check whether a closed circuit exists via the fifth power lines 245. In this way, the fifth power lines 144 can display (dynamic, i.e., real-time) information C4 as to whether the two electrical contacts 253-1, 253-2 are (currently) electrically connected to each other. A further safety condition can thus be that none of the electrical contacts 253-i may be electrically connected to any of the other electrical contacts 253-i.

[0093] Furthermore, sixth power lines 246 can be connected to one or more limit switches 252-i and to the safety device 140, by means of which the safety device 140 can check whether all limit switches 252-i are actually actuated. As with the laser welding gun 110, the filler wire holder 250 is designed such that, when a correct holder housing 259 is correctly installed, all limit switches 252-i are actuated. For example, the safety device 140 can apply a voltage to the sixth power lines 246 on one side, whereby each limit switch 252-i interrupts a circuit formed by the sixth power lines 246, and the circuit of the sixth power lines 246 is thus closed only when all limit switches 252-i are actuated.A further safety condition may thus be that all limit switches 252-i of the additional wire holder 250 must be actuated, or, specifically in the aforementioned variant, that the sixth power lines 246 must form a closed circuit. It is understood that it could also be provided that the sixth power lines 246 form a separate circuit for each limit switch 252-i, and based on the open / closed state of the respective circuit, the safety device 140 can then determine whether the respective limit switch 252-i has been actuated or not.

[0094] The possible safety conditions described above, which are associated with the image input interface 148 and / or the image processing module 149, can also be extended to the filler wire holder 250. This means that all tests described above for the tip housing 119 and the laser welding gun 110 can also be performed alternatively or additionally for the holder housing 259 and the filler wire holder 250 of the laser welding gun 210.

[0095] In particular, a further visual safety criterion may be that the image received by the image input interface 148 must show the auxiliary wire holder 250 with the holder housing 259 correctly mounted and / or undamaged and / or unmodified and / or that the holder housing 259 shown in the image must be intact and / or the like.

[0096] The optional features of the laser welding gun 110 described above regarding a code element (e.g., on the tip housing 119) and a code reading device (e.g., on the rest of the laser welding gun 110) are also applicable, alternatively or additionally, to the holder housing 259 and the filler wire holder 250. For example, a code element can be arranged on the holder housing 259, and a code reading device for reading this code element can be arranged on the filler wire holder 250. A further safety condition can then be that a code element, in particular a valid code element, is read by this code reading device, and the like.The optional database described above can thus also include mutually licensed combinations of laser welding gun 210, tip housing 119 and holder housing 259, whereby it is a safety condition that welding is only enabled if the identification codes of the currently recorded code elements and / or the device identification code of the remaining laser welding gun 210 represent a licensed combination.

[0097] The entire surface of the laser welding gun 110; 210 (possibly including the filler wire holder 250) is advantageously designed to be electrically insulated, with the filler wire 50 and the contact section 118 as necessary exceptions. For this purpose, surface areas that are not exposed to high temperatures, such as the handle 115, can be electrically insulated using plastic coatings or plastic covers. Plastics are generally tough and impact-resistant and are more robust than many ceramic or glass materials. The at least one safety condition can include a safety condition according to which a plastic cover with predetermined properties and according to predetermined parameters (i.e., in particular, correctly, intact, and / or unchanged) must be mounted on the laser welding gun 110; 210.For this purpose, the plastic cover can be manufactured, for example, by injection molding and can be designed with suitable undercuts and / or limit switches already integrated. Alternatively or additionally, the laser welding gun 110; 210 itself can also have additional limit switches, by means of which the safety device 140 can check whether the plastic cover is correctly installed.

[0098] If an image input interface 148 and an image processing module 149 are provided in the safety device 140, it may alternatively or additionally be provided that a visual safety criterion states that the (or each of several) plastic covers must be mounted on the laser welding gun 110; 210 with predetermined properties and / or according to predetermined parameters.

[0099] Fig. 5 shows a schematic flowchart for explaining a method according to a further embodiment of the present invention, namely a method for operating a laser welding device. For further explanation, reference numerals of the laser welding device 100 described above are used in some cases below. The method can be carried out with this laser welding device 100 and adapted according to all variants, options, and refinements described with respect to this laser welding device 100 (or generally a laser welding device according to the present invention), and vice versa. However, the method can also be carried out independently of the described laser welding device 100.

[0100] The method comprises at least one step S100 in which safety conditions are automatically checked by a safety device 140 of the laser welding device 100.

[0101] The safety conditions include a first safety condition, according to which a closed circuit must be present between a current terminal 120 of the laser welding device 100 and a contact section 118 of the tip 111 of the laser hand welding gun 110; 210 (for the contact of the tip 111 with a workpiece 1 to be welded) or between the current terminal 120 and a welding filler wire 50 held by a possible filler wire holder 250 of the laser hand welding gun 110; 210.

[0102] The safety conditions include at least a second safety condition, according to which a tip housing 119 with predetermined properties and according to predetermined parameters must be mounted on the laser welding gun 110; 210 and / or a holder housing 259 with predetermined properties and according to predetermined parameters must be mounted on the optional filler wire holder 250.

[0103] For example, if the laser welding gun 110; 210 is equipped with the electrical limit switches 112-i, 252-i described above, checking S100 of the safety conditions can be implemented by checking whether all of them are actuated. Alternatively, this can also be done as described above with reference to the image receiving interface 148 and the image processing module 149.

[0104] For this purpose, the method may comprise the additional steps: receiving S148 at least one image; automatically checking S149 whether a laser welding gun depicted in the received image meets at least one visual safety criterion. Fulfilling all predefined visual safety criteria may represent a further safety condition. A variety of possible visual safety criteria have already been explained above. For example, a visual safety criterion may include the requirement that a tip housing or a holder housing with a predefined external shape (as an optional predetermined property of the tip housing or the holder housing) must be visible in the at least one image.

[0105] Receiving S148 and / or checking S149 can be carried out in particular as explained above with reference to the image input interface 148 or the image processing module 149, i.e., for example, with associated apps on smartphones or tablets, using videos, checking additional properties of the at least one image, such as its age or its origin, and / or the like.

[0106] The predetermined parameters according to which the tip housing or the holder housing must be mounted may, for example, be whether the tip housing 119 or the holder housing 259 is correctly mounted.

[0107] Checking whether the tip housing 119 or the holder housing 259 is mounted correctly and / or intact and / or unmodified may, for example, when the laser welding gun 110; 210 is equipped with electrical contacts 113-i, 253-i, include or consist of ensuring that the electrical contacts 113-i, 253-i (partially or all) are not electrically connected to one another.

[0108] In addition, one or more visual security criteria can be defined to serve this purpose.

[0109] If the S100 test shows that all safety conditions are met (symbol “+” in Fig. 5), welding with the laser welding gun 110; 210 is automatically released by the safety device 140 in a step S200. If the test S100 shows that at least one of the safety conditions is not met (symbol "-" in Fig.5), welding is not enabled (i.e., inhibited or prevented) in a step S300—for example, by deactivating a laser light source 130, by interrupting a laser beam with a mechanical shutter, and / or the like. The arrows indicate that the checking S100 can be performed automatically at regular intervals, in particular continuously. List of reference symbols 1 workpiece 2 laser welding guns 3 Laser light source 4 current terminal 5 top 6 laser guides 7 Power line 8 power line 9 Laser beam 50 welding filler wire 100 laser welding device 110 laser welding gun 111 lace 112-i limit switch 113-i electrical contacts 115 Handle 118 Contact section 119 tip housing 120 current terminal 130 laser light source 140 Safety device 141 first power line 142 second power line 143 third power lines 144 fourth power lines 148 Image input interface 149 Image processing module 210 laser welding gun 245 fifth power lines 246 sixth power lines 250 additional wire holder 252-i limit switch 253-i electrical contacts 259 bracket housing C2-C5 Information on safety conditions S100..S300 process steps

Claims

[1] Laser welding device (100), with: a laser hand welding gun (110; 210) with an electrically conductive tip (111) and an electrically insulating tip housing (119), wherein the tip housing (119) consists at least partially of a glass and / or ceramic material, is mounted or mountable on the laser hand welding gun (110; 210), and, when mounted, insulates the tip (111) except for a contact section (118) of the tip (111) for contact of the tip (111) with a workpiece (1) to be welded; a current clamp (120) for clamping to the workpiece (1) to be welded; and a safety device (140) which is designed to check at least one safety condition and to release welding with the laser welding gun (110; 210) only if all safety conditions are met; wherein the at least one safety condition comprises at least a first safety condition, according to which a closed circuit must be present between the current terminal (120) and the contact section (118) of the tip (111) of the laser hand welding gun (110; 210) or between the current terminal (120) and a welding filler wire (50) held by any filler wire holder (250) of the laser hand welding gun (110; 210), wherein the tip housing (119) is designed to be exchangeable and wherein the at least one safety condition comprises at least one additional safety condition which checks whether the replaceable tip housing (119) is actually correctly mounted on the laser hand welding gun (110; 210). [2] Laser welding device (100) according to claim 1, wherein the tip housing (119) is made of the at least one glass and / or ceramic material. [3] Laser welding device (100) according to one of claims 1 or 2, wherein the laser welding gun (110; 210) has at least one limit switch (112-i) which is necessarily actuated when the tip housing (119) is correctly mounted on the laser welding gun (110; 210), and wherein the at least one safety condition comprises a second safety condition according to which each of the at least one limit switch (112-i) must be actuated. [4] Laser welding device (100) according to one of claims 1 to 3, wherein the laser hand welding gun (110; 210) further comprises a first electrical contact (113-1) and a second electrical contact (113-2) insulated therefrom, which are designed and arranged such that the first electrical contact (113-1) and the second electrical contact (113-2) would be electrically connected by a mounted, electrically conductive imitation tip housing, and wherein the at least one safety condition comprises a third safety condition according to which no electrical connection may exist between the first electrical contact (113-1) and the second electrical contact (113-2). [5] Laser welding device (100) according to claim 3 and claim 4, wherein the first and / or the second electrical contact (113-i) is or are integrated into a respective limit switch (112-i) of the at least one limit switch (112-i). [6] Laser welding device (100) according to one of claims 3 or 5, wherein at least one limit switch (112-i, 252-i) is designed as an optical limit switch, as a capacitive limit switch, or as a mechanical limit switch. [7] Laser welding device (100) according to one of the preceding claims, wherein the security device (140) comprises an image input interface (148) and a image processing module (149), wherein the image input interface (148) is configured to receive at least one image of the laser welding gun (110) and the image processing module (149) is configured to check whether the laser welding gun represented in the received at least one image meets at least one predetermined visual safety criterion, and wherein the at least one safety condition comprises a fourth safety condition according to which the laser welding gun depicted in the at least one received image must satisfy the at least one predetermined visual safety criterion. [8] Laser welding device (100) according to claim 7, wherein the at least one predetermined visual safety criterion comprises a first visual safety criterion according to which the laser welding gun (110; 210) must be visible with the tip housing (119) correctly mounted on the laser welding gun (110; 210) and / or intact and / or unmodified. [9] Laser welding device (100) according to one of the preceding claims, wherein the tip housing (119) has a code element and the laser hand welding gun (110; 210) comprises a code reading device which is configured to read the code element when the tip housing (119) is correctly mounted on the laser hand welding gun (110; 210), and wherein the at least one safety condition comprises a fifth safety condition according to which the code element must be read by the code reading device. [10] Laser welding device (100) according to claim 9, wherein the code element comprises an RFID code and the code reading device comprises an RFID reading device and / or the code element comprises an optical code and the code reading device comprises an optical reading device. [11] Laser welding device (100) according to one of the preceding claims, wherein the laser hand welding gun (110; 210) is designed such that the tip housing (119), when correctly mounted on the laser hand welding gun (110; 210), opens a mechanical shutter which releases a laser beam of the laser hand welding gun (110; 210) for laser welding. [12] The laser welding apparatus (100) of claim 1, wherein the tip housing (119) has a portion made of a ceramic coated metal. [13] Laser welding device (100) according to one of the preceding claims 1 to 12, wherein the safety device (140) is integrated into the laser hand welding gun (110; 210). [14] Laser welding device (100) according to one of the preceding claims 1 to 12, comprising a laser light source (130) which is designed to provide a laser beam for the laser hand welding gun (110; 210), wherein the safety device (140) is integrated into the laser light source (130). [15] Method for operating a laser welding device (100), comprising at least the steps: Automatic testing (S100), by a safety device (140) of the laser welding device (100), of safety conditions; wherein the safety conditions comprise a first safety condition according to which a closed circuit must be present between a current terminal (120) of the laser welding device (100) and a contact section (118) of a tip (111) of a laser hand-held welding gun (110; 210) of the laser welding device (100) or between the current terminal (120) and a welding filler wire (50) held by a possible filler wire holder (250) of the laser hand-held welding gun (110; 210); and wherein the safety conditions comprise at least a second safety condition, according to which a tip housing (119) with predetermined properties and according to predetermined parameters must be mounted on the laser hand welding gun (110; 210) and / or a holder housing (259) with predetermined properties and according to predetermined parameters must be mounted on the possible filler wire holder (250); and Automatic enabling (S200) of welding with the laser hand welding gun (110) if all safety conditions are met, and automatic prevention (S300) of welding with the laser hand welding gun (110) if at least one safety condition is not met.

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