Nozzle adapter for laser cutting head

Abstract

A device for connecting a nozzle (120) to a laser cutting head (30), wherein the laser cutting head (30) has a sensor arrangement (60) for capacitive scanning, an opening (36) for connection to a laser process and an opening (35) for connection to a purge gas (P), the device comprising: - a conductive adapter (110) having a first and a second end (114, 116) and a first passage (64) for connection to the laser method from the opening (36), wherein the first end (114) is attached to the sensor assembly (60), the second end (116) is attached to the nozzle (120), the conductive adapter (110) having a collar (115) arranged around it, the collar (115) defining one or more second passages (118) through it; and - a cover (130) configured to be positioned between the head (30) and the collar (115) and configured to enclose a space (95) that directs the purge gas (P) from the opening (35) to the one or more second passages (118) of the collar (115).

Description

Field of invention

[0001] The subject matter of the present invention relates to a device for connecting a nozzle to a laser cutting head and to a laser cutting head which has such a device. Brief description of the state of the art

[0002] Laser cutting heads use a laser beam to cut sheets of various materials (typically different types of metals and metal alloys). The laser cutting process requires precise control of the cutting head, and in particular, control of the gap between the nozzle tip of the cutting head (where the laser beam exits) and the surface of the material being cut (sometimes referred to as the "workpiece"). For this purpose, the laser cutting head uses optics and sensors to control the cutting process.

[0003] In general terms, a laser cutting head converts the energy of a high-power laser source (usually a CO2 or YAG laser) into a laser beam capable of precisely and controllably cutting (severing) a sheet of metal. The cutting head can guide the beam through a series of lenses and use optical fibers to transmit the beam. The cutting head focuses the beam to a spot size required for the process, and the focused beam is directed through a nozzle on the cutting head onto the sheet of metal to be cut.

[0004] Along with the laser beam, an accompanying gas (usually nitrogen or oxygen, sometimes also called cutting or process gas) can be directed onto the surface of the sheet metal. The gas serves either to assist the melting process (e.g., "oxyfuel cutting") or to blow the molten material away from the workpiece. Although the cutting gas used during the laser process can blow the material concentrically outwards from the nozzle, the nozzle must be positioned at a specific distance from the workpiece to achieve proper cutting and to prevent molten material from contaminating the nozzle and cutting head.

[0005] A wide variety of laser cutting heads are manufactured for different purposes. Each type of cutting head requires the ability to adjust, control, and monitor the gap between the nozzle tip and the workpiece surface. A typical system for monitoring (and controlling) this gap is based on a measured capacitance between the nozzle tip and the workpiece (with the air gap between the two acting as the dielectric for the capacitor). To function correctly, both the nozzle tip and the workpiece must be conductive and connected to a voltage source of a measuring system.

[0006] Numerous types of nozzles are used on laser cutting heads. These nozzles are typically made of metal, such as copper, and have a passage for the focused laser beam and the cutting gas. The nozzles can contain one or more component layers. The external shape of the nozzle, as well as any internal passage profiles, can vary from nozzle to nozzle, depending on the implementation and its application.

[0007] Under normal use, the nozzle can become worn and dirty, requiring replacement. When bevel cutting at acute angles, nozzle characteristics can interfere with sensor measurements used to monitor the distance or gap between the nozzle and the workpiece. At very acute angles, the existing nozzle and adapter configuration cannot prevent contaminants from affecting the optics and sensors of the laser cutting head.

[0008] The published Chinese utility model CN ​​204053247 U discloses a laser cutting head front section with a capacitor focus tracking function and relates to the technical field of laser processing equipment. The front end of the laser cutting head comprises a housing and a copper flow guide tube. The housing has a hollow structure. An upper insulating ring is pressed onto the upper end of the copper flow guide tube and attached to the housing. The lower end of the copper flow guide tube penetrates the bottom of the housing, and a nozzle seals the penetration section. A lower insulating ring is positioned between the section of the copper flow guide tube located within the housing and the housing itself, and is situated beneath the upper insulating ring. An annular groove is formed between the housing and the lower insulating ring. A circle of heat-dissipating holes is formed below the annular groove.An external sensor is permanently attached to the housing. Corresponding through-holes are formed in the side wall of the housing and in the side wall of the lower insulating ring. A insertion pin is inserted into these through-holes. One end of the insertion pin is connected to the sensor, and the other end is connected to the copper flow guide tube. An insulating sleeve encloses the insertion pin. Thanks to the laser-cut head on the front, capacitor tracking is precise, the sensor is easy to remove, and inspection and maintenance are simplified.

[0009] The published German patent DE 10 2009 024 957 B3 relates to a modular system for laser cladding of internal surfaces of workpieces. A coating can be applied to internal surfaces using powdered filler material. The object of the invention is to provide methods for laser cladding or coating of internal surfaces of workpieces with variable immersion depth, increased flexibility, and independence from the direction of processing. A system according to the invention includes a feed for powdered filler material, as well as separate feeds for shielding gas and coolant. It comprises a coupling module for the laser beam, at least one beam guidance module for the laser beam, and a processing module, all of which can be connected to one another.In this process, a collimated laser beam is directed via the coupling module and through the beam guidance module(s) onto an optical element that focuses the laser beam onto the surface of the workpiece to be processed. The processing module includes a nozzle with an outlet opening for the laser beam and the shielding gas, as well as at least one channel with an outlet opening for powdered filler material.

[0010] Published US patent application US 2019 / 0366483 A1 discloses a unified adapter for attaching a cutting nozzle to a laser cutting head, comprising an inner ceramic cylinder, a conductive shield sintered to the outer side wall of the ceramic cylinder, a conductive threaded holder (for receiving the cutting nozzle) mounted in an opening at one end of the ceramic cylinder, and a coaxial connector (for connecting to external measuring equipment) mounted at the opposite end of the ceramic cylinder. A pair of wires is shaped to be embedded in the ceramic material and provide separate electrical connections between the coaxial connector and the threaded holder, and between the measuring device and the threaded holder.The various components are permanently bonded to the ceramic body by sintering, creating a uniform structure that is less susceptible to the high accelerations and high temperatures encountered during laser cutting.

[0011] The published Japanese patent application JP H11-314 187 A discloses a machining head that can be used in both dry and humid atmospheres and that controls the clearance against a workpiece during machining. It also cools the workpiece by dissipating heat generated during machining and stabilizing the temperature. The machining head is designed such that, within a protective electrode serving as a sensor head located in the lower part of the machining head body, an inner nozzle is screwed onto a nozzle nut secured by an outer and an inner nozzle nut holder. An outer nozzle is installed on the outside of this inner nozzle. Inside the sensor head 9, a coolant channel with an outer and an inner lining is formed; and within this channel, a coolant supply channel is provided through which a coolant flows into the channel from the tangential direction.This allows the sensor to be used in both dry and humid atmospheres, thereby improving the profiling function.

[0012] The published German patent DE 42 01 640 C1 discloses a nozzle for machining a workpiece, comprising a nozzle body, a sensor element arranged at the tip of the nozzle body for non-contact measurement, a signal line connection, a further line connection and a first line via which the sensor element is in contact with the signal line connection, wherein the sensor element is in contact with a second line at a distance from the first line and the second line is connected to the further line connection via a resistor.

[0013] The subject of this disclosure is aimed at overcoming or at least reducing the effects of one or more of the problems mentioned above. Summary of the invention

[0014] A device according to this disclosure is used to connect a nozzle to a laser cutting head. The head has a sensor array for capacitive scanning, an opening for transmitting a laser process, and an opening for transmitting a purge gas. The device includes a conductive adapter and a cover. The conductive adapter has a first and a second end and features a first passage for communicating with the laser process from the opening. The first end can be attached to the sensor array and the second end to the nozzle. The conductive adapter has a collar that defines one or more second passages through it. The cover is designed to be positioned between the head and the collar and encloses a space that directs the purge gas from the opening to the one or more second passages of the collar.

[0015] A laser cutting head shown here uses a nozzle to perform a laser process. The head comprises a housing, a conductive adapter, and a cover. The housing has a sensor array for capacitive scanning, an orifice for transmitting the laser process, and an orifice for conveying purge gas. The conductive adapter has a first and a second end and features a first orifice for communicating with the laser beam at the orifice. The first end is attached to the sensor array, and the second end is attached to the nozzle. The conductive adapter has a collar that defines one or more second orifices through it. The cover is positioned between the end of the housing and the collar and encloses a space that directs the purge gas from the orifice to the one or more second orifices.

[0016] The foregoing summary is not intended to summarize every possible embodiment or aspect of the present disclosure. Brief description of the characters Fig. Figure 1A shows a perspective view of a laser cutting head according to the present disclosure. Fig. Figure 1B illustrates a laser cutting system with a robot arm and a laser cutting head according to the present disclosure. Fig. Figure 2A shows a perspective view of a nozzle attachment of the present disclosure. Fig. Figure 2B shows a top view of the nozzle attachment of the present disclosure when cutting at an acute angle with a laser cutting head. Fig. Figure 2C shows a perspective view of the nozzle attachment, which features an alternative nozzle. Fig. 2D shows a part without nozzle and adapter in an exposed view of a laser cutting head. Fig. Figure 3A shows a cross-sectional view of a nozzle attachment of the present disclosure on a laser cutting head. Fig. Figure 3B shows a schematic representation of the laser beam, the process gas, and the purge gas in relation to the components of the nozzle attachment. Fig. 3A. Fig. Figure 4A shows a cross-sectional view of the nozzle attachment of the present disclosure, which has a different nozzle. Fig. Figure 4B shows a schematic representation of the laser beam, the process gas, and the purge gas in relation to the components of the nozzle attachment. Fig. 4A. Fig. Figure 5 shows a cross-sectional view of another nozzle attachment of the present disclosure on a laser cutting head. Detailed description of the invention

[0017] The technical problem of the invention is solved by the features of the independent claims. Further embodiments are specified in the dependent claims.

[0018] Fig. Figure 1A shows a perspective view of a laser cutting head 30 according to the present disclosure. The laser cutting head 30 comprises a housing 32 that accommodates various internal optics. A port at one end of the housing 32 can be connected to a laser cable 40, which conducts the laser energy into the laser cutting head 30. An output assembly or nozzle attachment 50 at the other end of the housing 30 has a nozzle 120 from which a laser beam is directed for cutting. The nozzle attachment 50 enables the focused laser beam to be emitted from the housing 32 to achieve the purpose of the laser process, such as welding, additive manufacturing, cutting, etc. The nozzle attachment 50 also includes sensor components (not shown) for monitoring the distance of the nozzle 120 to a workpiece, as disclosed below.

[0019] To protect the internal optics inside the housing 32, the laser cutting head 30 can include a cover slide cartridge 34 containing a replaceable cover slide. This cover slide acts as a transparent window between the interior of the housing 32 (which contains the internal optics) and the external environment (which is exposed to the laser process). The cartridge 34 can be removed and replaced through an access door on the side of the head 30. The nozzle attachment 50 protects the laser cutting head 30 in a manner disclosed below.

[0020] In general, the laser cutting head 30 can be used with a gantry arrangement, a robot arm or other device so that the laser cutting head 30 can be moved relative to a workpiece. Fig. Figure 1B shows, for example, a laser cutting system 10 in which the laser cutting head 30 is connected to a robot arm 20, which can manipulate the laser cutting head 30 relative to a workpiece WP that is subjected to the laser process of this disclosure. The wiring 22 transmits the control and measurement data as well as the energy to the laser cutting head 30. The wiring 22 also transmits the flow of the gases used in the laser cutting process described herein. The laser cable 40 supplies the laser energy to the head.

[0021] 30, which directs the laser beam from the nozzle attachment 50 at the end of the head 30.

[0022] In general, the laser cutting system 10 includes a control system 12 that controls the operation of the various components, namely the robot arm 20, the laser cutting head 30, etc. The laser cutting system 10 also includes a measuring system 14, which in the present example is used together with the control system 12 to measure the distance or gap between the cutting nozzle 120 and the workpiece WP in order to facilitate the cutting process.

[0023] Depending on the shape of the workpiece WP and the cuts to be made, the laser cutting head 30 can be manipulated by the robot arm 20 at various angles and orientations relative to the workpiece WP. During the process, the components of the nozzle attachment 50 can measure the distance between the nozzle 120 and the workpiece WP. This is done via the capacitance between the nozzle 120 and the workpiece WP, with the air gap between them acting as the dielectric. Using this measured capacitance, the positioning of the head 30 relative to the workpiece WP can be controlled to achieve the desired laser effect.

[0024] As expected, the nozzle 120 is damaged during use by the heat generated by the process. Furthermore, the process can produce deposits, abrasion, splashes, recoil, etc., which can damage the nozzle 120 and impair the capacitive sensing of the head 30. The features of the nozzle attachment 50 of this disclosure can help to reduce damage to the nozzle 120 and protect the capacitive sensor.

[0025] Fig. Figure 2A shows a perspective view of the nozzle attachment 50 according to the present disclosure. The nozzle attachment 50 includes a cap 52, which is mounted on the laser cutting head 30. An adapter 110 is connected to internal components, and the nozzle 120 is attached to the adapter 110. A cover 130 is located between the adapter 110 and the cap 52. To cool the nozzle 120 and to provide additional protection against foreign matter, the adapter 110 directs a purge gas through the openings 118 directly adjacent to the nozzle 120.

[0026] For very acute head angles 30, as in Fig. As shown in Figure 2B, the components of the nozzle attachment 50 can be positioned close to the workpiece WP and are therefore more exposed to contamination and interference. To protect the components while still allowing the head 30 to be used at an acute angle, the nozzle attachment 50 includes the cover 130 or the belt, which encloses part of the adapter 110 for the nozzle 120. As described in more detail below, the cover 130 also encloses parts of the head housing, which includes sensor elements and an opening for purge gas flow. The cover 130 can have a metal body with an electrically insulating shield, such as a ceramic coating. In other embodiments, the cover 130 can be made of plastic or ceramic.

[0027] Depending on the laser process, different nozzles can be used on the nozzle attachment 50. Fig. Figure 2C, for example, shows the nozzle attachment 50, which has a different, larger nozzle 120' attached to the adapter 110 than the one shown previously. The advantage of the nozzle attachment 50 in cooling the larger nozzle 120' and creating additional shielding with purge gas can also be achieved with such a larger nozzle 120', in addition to the protection of the sensor elements provided by the cover 130, the adapter 110, and the like. Further details will be described later.

[0028] Fig. Figure 2D briefly shows the nozzle attachment 50, which includes the nozzle 120, the adapter 110, and the cover 130, all of which have been removed to expose the internal components. The elements of the sensor unit 60 shown include a ceramic body 62 containing a conductive holder 66. The adapter 110 is screwed into this conductive holder 66. The ceramic body 62 is surrounded by a shield 72, which defines an annular gap 54 with the lip of the cap 52 of the attachment. This annular gap 54 serves as an opening for the purge gas, as described below. It is evident that the features of the nozzle attachment 50 shown here can protect these internal elements of the sensor unit 60 from contamination and the like during the laser process.

[0029] With further reference to details, it shows Fig. Figure 3A shows a cross-sectional view of a nozzle attachment 50 of the present disclosure on a laser cutting head 30. As already mentioned, the laser cutting head 30 is usable for laser processing with a nozzle 120. During laser processing, a laser beam (B) and a process gas (G) are emitted from the laser cutting head 30 and from the nozzle 120 at the nozzle attachment 50. In addition, a purge gas (P) is also directed from the laser cutting head 30 and from the nozzle attachment 50 next to the nozzle 120. This purge gas (P) fulfills the purpose disclosed here of (i) contributing to the cooling of the nozzle 120 and (ii) creating additional shielding around the active processing area beyond the nozzle 120.

[0030] The laser cutting head 30 has a housing 32, one end of which may include an end plate 38 from which the laser beam (B), the process or cutting gas (G), and the purge gas (P) can exit. The laser beam (B) and the process gas (G) exit from inside the housing 32 through an opening 36 and then through the sensor assembly 60, while the purge gas (P) can exit from another location in the housing 32 through a passage or another opening 35, which is shown only schematically. The components of the sensor assembly 60 are attached to the end of the housing 30, and the cap or holder 52 covers the assembly 60 at the end of the housing 30. The conductive adapter 110 is attached to the sensor assembly 60, and the cover or belt 130 is positioned between the sensor assembly 60 and the conductive adapter 110. Finally, the nozzle 120 is attached to the conductive adapter 110.

[0031] The cap 52 acts as an external protective element for the sensor assembly 60. It protects the assembly 60 from contact with other manufacturing / production elements that could damage the assembly 60 or otherwise interfere with its function. As shown in detail, the cap 52, which may be conical, has a large circumferential end that can be screwed onto the end plate 38 and fits against a retaining ring 70 used between the sensor assembly 60 and the base plate 38. A variety of seals can be used to seal the assembly against external influences and prevent the ingress of purge gas (P).

[0032] The nozzle attachment 50 has an opening 54 from which a portion of the purge gas (P) escapes. For example, an annular space 54 is provided between a lip of the cap 52 and the outer edge of the sensor unit 60. The purge gas (P) can escape from this annular space 54 towards the end of the adapter 110 and the nozzle 120 for the purposes disclosed here.

[0033] The sensor assembly 60 comprises a ceramic body 62 and a conductive holder 66. The ceramic body 62 has a first opening 64 through which the laser beam (B) and any process gas (G) can pass. The conductive holder 66 is located in the first opening 64. The sensor assembly 60 may also include a conductive grounding shield 72 arranged around the ceramic body 62. As explained in more detail below, the conductive holder 66 and the conductive grounding shield 72 are electrically connected to a voltage and to ground, respectively.

[0034] The conductive adapter 110 has a first and a second end 114, 116 with a second passage 112 through which the laser beam (B) and any process gas (G) can flow. The first end 114 is configured to be attached to the conductive holder 66, while the second end 116 defines a receiving vessel in which the nozzle 120 can be attached. The first end 114 can, for example, include an external thread that screws into the conductive holder 66. The receiving vessel 116 can define an internal thread into which the nozzle 120 can be screwed. The nozzle 120, in turn, defines a passage 122 extending from end 126 to end 124 to allow the laser beam (B) and the process gas (P) to pass through.

[0035] The conductive adapter 110 has a collar 115 arranged around it, and the cover 130 is arranged between the sensor assembly 60 and the collar 115. As shown, the cover 130 can have a conical shape with a large circumferential rim designed to engage with the cap 52 and a small circumferential rim designed to engage with the collar 115 of the conductive adapter 110. The conductive adapter 110 can include a seal 117 arranged around the collar 115 to seal the cover 130.

[0036] The collar 115 defines one or more gas passages 118 from one side to the other for the passage of a portion of the purge gas (P), as described herein. In this way, the cover 130 encloses an interior space 55 that directs the purge gas (P) from the opening 54 to the one or more passages 118 of the collar 115. One or more outlets of the one or more passages 118 in the collar 115 are preferably arranged directly next to the nozzle 120, which can increase the cooling of the nozzle 120 and extend its service life.

[0037] It is evident that the adapter 110, with its flow channels 118, can assist in the expulsion of the purge gas (P), thereby effectively preventing contaminants from reaching the components of the head 30 and the nozzle attachment 50. The adapter 110, with its flow channels 118, also controls the diffusion area and the size of the purge gas flow, which can be adjusted to the cutting operation being performed.

[0038] It is evident that the cutting nozzle 120 can assist in the discharge of the cutting or process gas (G) used during cutting. The size of the nozzle opening 124 can be selected based on the thickness of the material to be cut. The nozzle 120 prevents molten material from flowing back from the workpiece into the laser head 30, thus protecting the internal components of the laser cutting head 30. The nozzle 120 also provides a capacitance signal that is used by the laser head 30's adjustment system to maintain stable laser operation.

[0039] In some configurations, the internal shape of the laser head nozzle 120 can control the flow and pressure of the process gas (G). A single-layer nozzle 120 can be used for melt cutting, with nitrogen as the auxiliary gas for cutting stainless steel and aluminum sheet. A two-layer nozzle 120 can be used with oxygen as the auxiliary gas for cutting carbon steel. The nozzle 120 typically has a conical shape and can have a single layer or multiple layers. A two-layer nozzle, for example, can have an inner core to increase the velocity of the process gas (G), which offers several advantages. The nozzle orifice 124 and the nozzle thickness are configured for the present implementation.

[0040] Referring further to the details of the sensor arrangement 60, which is used to detect the distance of the nozzle 120 from a workpiece, the cylindrical ceramic body 62 is used as the base element of the sensor arrangement 60. The ceramic material of the body 62 is insulating. The electrical connections between the nozzle of the laser cutting head 120 and an external measuring system (14) can be sintered onto (or embedded in) the outside of the cylindrical ceramic body 62. In this way, the electrical connections are permanently fixed and cannot move (even under high pressure conditions) and are able to function properly at high temperatures.

[0041] These electrical connections can include the following: a pair of electrical conductors (wires) 82, 86, the conductive holder 66, the outer cylindrical shield 72 (also conductive), and a connector 65. The conductive adapter 110 and the nozzle 120 engage with the conductive holder 68. Together, they direct the laser beam (B) and any process gas (G) from the cutting head 30 onto the workpiece.

[0042] The socket connector 65 can be a coaxial cable connector comprising a central conductor and an outer ground conductor (with insulating material in between). A wire 86 is used to conduct an electrical signal (voltage) along the central conductor to the conductive holder 66, which is itself made of a conductive material (e.g., stainless steel). During assembly of the laser cutting head 30, the adapter 110 is screwed into the conductive holder 66 (specifically through the matching threads), and the nozzle 120 is screwed into the adapter 110. Consequently, the nozzle 120 becomes electrified due to the connections established by the wire 86 and the threaded holder 66.

[0043] The other wire 82 is positioned inside the ceramic body 62 to provide the conduction path for the outer ground or shield 72. This outer shield 72 is in the form of a sleeve configured to slide over and contact the outer surface of the cylindrical ceramic body 62. The shield 72 is permanently attached around the ceramic body 62 and is preferably made of stainless steel.

[0044] The combination of the conductive holder 66, the ceramic body 62, and the shield 72 provides the connection arrangement for exciting the connected nozzle 120 and minimizes problems with internal interference and parasitic induction that would otherwise affect the capacitive measurements of the associated measuring system 14. In addition to the cap 52, the cover 130, in conjunction with the collar 115 and the seal 117 of the adapter 110, protects these components of the measuring arrangement 60 during operation and simultaneously allows the head 30 to be used at small acute angles, as described here.

[0045] As already mentioned, the conical cap 52, for example, has a large circumferential end that is attached to the end 38 of the housing 30, and a small circumferential end that defines the annular gap 54 around the ceramic body 62 for the passage of the purge gas (P). One circumference of the collar 115 of the conductive adapter 110 lies within a conical angle (A) extending from a tip of the nozzle 120 to the large circumferential end of the conical cap 52. This configuration makes it possible to position the laser cutting head 30 at small acute angles relative to a workpiece during laser cutting, as already described in Fig. 2B mentioned.

[0046] As can be seen, molten deposits or similar contaminants that enter the annular gap 54 can obstruct the flow of purge gas (P) from the laser cutting head 30. Furthermore, molten debris or other contaminants that enter the sensor assembly 60 can disrupt its detection function. To this end, the cover 130, the collar 115 of the adapter 110, the seal 117, and other features protect the gap 54 and the sensor assembly 60. In addition, the supplied purge gas (P) can actively cool the nozzle 120, preventing overheating and wear. The purge gas (P) can also act as a curtain (shield) for the cutting gas flow (G).

[0047] Fig. Figure 3B, for example, shows a schematic view of the laser beam (B), the process gas (G) and the purge gas (P) in relation to the components of the nozzle attachment 50. Fig. 3A. Both gas streams (P, G) are independently adjustable with respect to flow rate, pressure, and gas type. This allows the operator to create an inert gas curtain from the purge gas (P) around any oxygen-based or other process gas (G). Furthermore, the angle of the purge gas stream (P) can be adjusted to the requirements of the cutting process. For example, the purge gas stream (P) can be directed at a specific angle onto the surface of the workpiece / material so that the purge gas (P) can act as a process jet, cooling / deflecting the process emissions from the laser cutting head 30 and the gantry 20. The separately supplied purge gas (P) is intended to protect the sensor measurement system from process-related contaminants such as splashes, vapors, and general dirt. Finally, the targeted supply of the purge gas (P) to the process can be used as an active cooling medium for the nozzle 120 and / or as an additional process jet.

[0048] Fig. Figure 4A shows a cross-sectional view of the nozzle attachment 50, which, as mentioned previously, has a larger nozzle 120'. Similar components to those in the other configurations have the same reference numerals and are not described again, but their details are included here.

[0049] As shown, the nozzle 120' projects beyond the collar 115 of the adapter 110. To allow the purge gas (P) to flow out of the flow channels 118, lateral chamfers 119 can be provided on the side of the collar 115. The purge gas (P) from the flow channels 118 can escape outside the sides of the adapter 110 and still fulfills the purpose of cooling the nozzle 120' and creating additional shielding.

[0050] Fig. Figure 4B, for example, shows a schematic view of the laser beam (B), the process gas (G) and the purge gas (P) in relation to the components of the nozzle attachment 50. Fig. 3B. The nozzle adapter 110 cools the nozzle 120' by directing the purge gas (P) flow to the nozzle 120'. The purge gas (P) can also act as a sheath around the process gas (G). This function depends on the design of the nozzle 120' and the nozzle adapter 110. Here, the nozzle adapter 110 can create a horizontal cross-jet of the purge gas (P) to prevent contamination. Nevertheless, the purge gas (P) is still able to cool the nozzle 120'.

[0051] An alternative configuration of the nozzle attachment 50 is in Fig. 5 shown. Similar components to those in the other configuration have the same reference numerals, but their details are included here. In this arrangement, the separate features of the conical cap and the cover are shown in the Fig.3A & 4A are integrated into a uniform cover 90 which encloses a space 95 and defines the opening 94 for the purge gas (P) so that it reaches the openings 118 in the collar 115 of the adapter.

[0052] As revealed here, the nozzle attachment 50 can mitigate problems that may occur during bevel cutting operations. The nozzle attachment 50 prevents contaminants from entering the sensor assembly 60 and, together with the purge gas (P), can generate a cooling effect to cool the nozzle 120. The adapter 110 and the cover 130 are configured so as not to interfere with the capacitive sensor assembly 60 and the system (14) of the cutting head 30. Furthermore, the attachment 50 has a modular design, allowing it to be used with a variety of different nozzle types.

Claims

[1] A device for connecting a nozzle (120) to a laser cutting head (30), wherein the laser cutting head (30) has a sensor arrangement (60) for capacitive scanning, an opening (36) for connection to a laser process and an opening (35) for connection to a purge gas (P), the device comprising: - a conductive adapter (110) having a first and a second end (114, 116) and a first passage (64) for connection to the laser method from the opening (36), wherein the first end (114) is attached to the sensor assembly (60), the second end (116) is attached to the nozzle (120), the conductive adapter (110) having a collar (115) arranged around it, the collar (115) defining one or more second passages (118) through it; and - a cover (130) configured to be positioned between the head (30) and the collar (115) and configured to enclose a space (95) that directs the purge gas (P) from the opening (35) to the one or more second passages (118) of the collar (115). [2] The device according to claim 1, wherein the second end (116) defines a receiving container in which the nozzle (120) can be attached. [3] The device according to claim 2, wherein the receiving container comprises an internal thread configured to be screwed onto the nozzle (120). [4] The device according to claim 1, wherein the first end (114) of the conductive adapter (110) comprises an external thread configured to allow it to be screwed onto the conductive element. [5] The device according to claim 1, wherein the cover (130) is made of plastic, metal or ceramic. [6] The device according to claim 1, wherein the conductive adapter (110) comprises a seal (117) arranged around the collar (115) and designed to engage sealingly in a lip of the cover (130). [7] The device according to claim 1, wherein the cover (130) has one or more cones having a large circumferential edge configured to engage the sensor arrangement (60) and having a small circumferential edge configured to engage the collar (115) of the conductive adapter (110). [8] The device according to claim 7, wherein the one or more cones comprise a cap (52) and a belt (130). [9] The device according to claim 1, wherein one or more outlets of one or more second passages of the collar (118) are arranged directly next to the nozzle (120). [10] The device according to claim 1, wherein the cover (130) is replaceable. [11] A laser cutting head (30) which uses a nozzle (120) to perform a laser process, wherein the head (30) comprises the following: - a housing (30) comprising a sensor arrangement (60) for capacitive scanning, an opening (36) for transmitting the laser process and an opening (35) for transmitting a purge gas (P); - a conductive adapter (110) having a first and a second end (114, 116) and a first passage (64) for connecting to the laser beam of the aperture (36), wherein the first end (114) is attached to the sensor assembly (60) and the second end (116) to the nozzle (120), wherein the conductive adapter (110) has a collar (115) arranged around it, the collar (115) defining one or more second passages (118); and - a cover (130) arranged between the end (38) of the housing (30) and the collar (115) and enclosing a space (95) which directs the purge gas (P) from the opening (35) to the one or more flow passages (118). [12] The laser cutting head (30) according to claim 11, wherein the sensor arrangement (60) comprises: - a ceramic body (62) having the opening (36) for the laser process; and - a conductive holder (66) which is arranged in the opening (36) of the ceramic body (62). [13] The laser cutting head (30) according to claim 12, wherein the sensor arrangement (60) comprises a conductive grounded shield (72) arranged around the ceramic body (62), wherein the conductive adapter (110) and the conductive grounded shield (72) are in electrical communication with a voltage difference. [14] The laser cutting head (30) according to claim 12, wherein the first end (114) of the conductive adapter (110) comprises an external thread configured to allow it to be screwed onto the conductive holder (66). [15] The laser cutting head (30) according to claim 11, wherein the opening (36) is designed to allow a laser beam and a process gas (G) to pass through for the laser process. [16] The laser cutting head (30) according to claim 11, wherein the second end (116) of the conductive adapter (110) defines a receiving container in which the nozzle (120) is mounted. [17] The laser cutting head (30) according to claim 16, wherein the receptacle comprises an internal thread designed to be screwed onto the nozzle (120). [18] The laser cutting head (30) according to claim 11, wherein the cover (130) is made of plastic, metal or ceramic. [19] The laser cutting head (30) according to claim 11, wherein the conductive adapter (110) comprises a seal (117) arranged around the collar (115) and sealingly enclosing the cover (130). [20] The laser cutting head (30) according to claim 11, wherein the cover (130) has a cone having a large circumferential edge designed to engage with the sensor arrangement (60) and a small circumferential edge configured to engage with the collar (115) of the conductive adapter (110). [21] The laser cutting head (30) according to claim 11, wherein one or more outlets of the one or more flow channels of the collar (115) are arranged next to the nozzle (120). [22] The laser cutting head (30) according to claim 11, wherein the sensor arrangement (60) has a conical cap (52) having a large circumferential end that is attached to the end (38) of the housing (30) and a small circumferential end that defines an annular gap (54) around the ceramic body as an opening; and wherein a circumference of the collars (115) of the conductive adapter (110) lies within a conical angle (A) extending from a first circumference to a tip of the nozzle (120) and the large circumferential end of the conical cap (52). [23] The laser cutting head (30) according to claim 11, wherein the cover (130) is replaceable.

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