Apparatus, system and method for correcting a laser device

Abstract

According to the present invention, an apparatus (1) for calibrating a laser device is proposed, the apparatus being designed to freely position a working laser beam within a predetermined working area. The apparatus comprises: a sensor plate (3) having one or more sensor fields (5) arranged within the working area; an orifice gauge (4) having one or more calibration channel openings (6), wherein at least one or more calibration channel openings (6) are respectively arranged within the areas of at least one or more sensor fields (5); and a laser guiding device for providing a guiding laser beam along the beam path of the working laser beam to calibrate the laser device.

Description

Technical Field

[0001] The present invention relates to apparatus, systems and methods for calibrating laser devices designed to freely position a working laser beam within a predetermined working area. Background Technology

[0002] 3D printing can produce a variety of three-dimensional components with complex geometries. The 3D workpiece is built layer by layer. This construction is carried out in a computer-controlled manner using one or more liquid or solid materials according to a pre-defined size and shape (CAD). During construction, physical or chemical hardening or melting processes occur. Typical materials for 3D printing include plastics, synthetic resins, ceramics, and metals.

[0003] 3D printing is a generative or additive manufacturing method. The most important 3D printing technologies are selective laser melting (SLM) and electron beam melting (EBM) for metals, and selective laser sintering (SLS) for polymers, ceramics, and metals.

[0004] Another generation method is selective melting and solidification. In this type of method, metal powder or wire is melted and solidified layer by layer, allowing the generation of three-dimensional components. Because energy is introduced locally and in a confined manner using a laser beam, the resulting molten pool is small. This makes it possible to create complex structures. The corresponding processes are commercially available as Laser Engineering Net Shaping (LENS), Direct Metal Deposition (DMD), Laser Additive Manufacturing (LAM), Selective Laser Melting (SLM), or Laser Metal Deposition (LMD).

[0005] In selective laser sintering (SLS / LMF), a layer of powder material is coated onto the work surface (build platform). The loose powder is selectively melted by a laser beam. Depending on the material used, the powder particles are bonded within the layer and to the underlying layer. Two basic development directions can be distinguished for the production of metal parts. Besides using laser radiation to directly solidify metal powder materials (direct laser metal sintering), a combination of SLS-coated metal powder and subsequent heat treatment (IMLS) was established in the early stages for producing metal components.

[0006] Direct metal laser sintering (DMLS) uses single-component or multi-component metallic materials. In particular, it uses DMLS multi-component powders composed of different alloying elements. The low-melting-point components in the powder are melted by the laser beam and flow around the high-melting-point components used as structural agents.

[0007] In electron beam melting (EBM), the process flow essentially corresponds to that of laser-based methods. Loose metal powder is melted at specific points in a powder bed, either via a nozzle or a filament, and subsequently solidified into the desired profile. The energy required for this is introduced via an electron beam. This method is typically carried out in a negative pressure chamber filled with inert gas.

[0008] In electron beam melting, similar to selective laser melting (SLM), high energy is applied to melt building materials. The energy is not supplied via a high-performance laser, but rather via a powerful electron beam, which is deflected and positioned by a strong magnetic coil. The electron beam melting process must be carried out under high vacuum. This significantly limits the construction space required for equipment operating using selective electron beam melting.

[0009] In recent years, methods for improving the processing of single-component metallic materials have been developed. One such method is commercially available, for example, under the name Selective Laser Melting (SLM).

[0010] In contrast to selective laser sintering (SLS), selective laser melting (SLM) uses a laser beam to introduce significantly more energy into the powder bed, resulting in true material melting in the affected areas. Therefore, this produces more homogeneous objects with higher density compared to the SLS method.

[0011] Laser cladding is a type of cladding that applies a surface to a workpiece by melting and simultaneously applying virtually any material. This can be done in powder form, such as metal powder, or using welding wire or ribbon. In laser cladding, the heat source is a high-power laser, primarily a diode laser or fiber laser; earlier examples included CO2 lasers and Nd:YAG lasers.

[0012] In laser cladding using powder, a laser typically heats the workpiece in a defocused manner, causing it to locally melt. Simultaneously, an inert gas mixed with fine metal powder is supplied. At the heated site, the metal powder melts and bonds with the metal of the workpiece. Besides metal powder, ceramic powder materials, especially hard materials, can also be used. Laser cladding using wire or strip works similarly to the powder method, however, using wire or strip as an additional material.

[0013] Therefore, additive manufacturing methods utilize powder beds, powder conveying devices, or wire conveying devices, wherein the starting material is then melted by means of a laser beam, electron beam, plasma / electric arc, and then solidified. Furthermore, inert or reactive gases are used as process gases in additive manufacturing methods.

[0014] The goal of the above-mentioned manufacturing method is to ensure the most efficient energy introduction possible, so as to achieve a safe manufacturing process and high component quality.

[0015] In the method described, attempts are made to reduce the critical effects and processes during energy introduction through appropriate measures. The use of a substrate with an inherently tight structure, process control under an inert gas atmosphere, or novel scanning strategies for exposing powders using laser energy are known herein.

[0016] DE 10 2011 006 553 A1 discloses a method for determining the focal position or beam profile of a light beam by means of an orifice plate and a downstream detector. Instead of a single orifice plate, an orifice plate having multiple orifices, each defining a measurement point, can also be used.

[0017] DE 10 2009 016 585 A1 describes a method and apparatus for calibrating an irradiation device, particularly for generating manufactured components, wherein an image conversion plate is provided, which is locally irradiated by means of energetic radiation. The image conversion plate converts the radiant energy into detectable light, which is detected by a detector.

[0018] DE 10 2020 122 670 A1 describes another device for calibrating irradiation equipment, particularly 3D printing equipment, wherein a probe element is positioned outside the working area to calibrate the position of the beam. The probe element may have an opening, behind which an optical sensor for probing the beam is arranged. DE 10 2020100 217A1 describes a method for automatically positioning a laser beam relative to the nozzle of a laser processing head. Summary of the Invention

[0019] The object of the present invention is to provide an apparatus and method for calibrating a laser device, suitable for freely positioning a working laser beam in a predetermined working area so as to arrange the working laser beam in the working area with a predetermined accuracy.

[0020] Another object of the present invention is to provide an apparatus and method for calibrating laser devices that achieves high reproducibility.

[0021] In addition, an object of the present invention is to provide improved equipment and methods for additive manufacturing, so as to provide components more easily, faster and / or with higher quality.

[0022] Another object of the present invention is to provide an alternative method for additive manufacturing.

[0023] One or more of the stated objectives are achieved through the features of the independent patent claims. Advantageous design solutions are described in the dependent claims.

[0024] According to the present invention, an apparatus for calibrating a laser device is provided, the apparatus being configured to: freely position a working laser beam within a predetermined working area. The apparatus includes a sensor plate having one or more sensor fields, the sensor plate being arranged within the working area;

[0025] An orifice gauge with multiple calibration channel openings, each of which is arranged in a corresponding region of the sensor field;

[0026] A control device is used to determine the relative position of the sensor fields with respect to each other after the sensor fields have been exposed through the calibration channel opening of the orifice gauge.

[0027] A guiding laser device is provided to provide a guiding laser beam along the path of the working laser beam, so as to calibrate the laser device by means of a sensor field scanning of the guiding laser beam.

[0028] When calibrating a laser device using sensor fields, where the relative positions of the sensor fields are determined, an orifice gauge can be arranged on or removed from the sensor plate. Since the relative positions of the sensor fields are determined, the relative positions of a guide laser beam aligned with one of the sensor fields can be determined relative to other positions of guide laser beams aligned with the same or another sensor field.

[0029] The laser device is preferably a laser device used in additive manufacturing components. However, alternatively, within the scope of the invention, other laser devices, such as those used for laser cutting, laser drilling, etc., can also be calibrated using the device according to the invention. A common feature of these devices is that the working laser beam of the laser device can travel along a working area to perform a predetermined work process there. The working area is preferably a build platform of an additive manufacturing device.

[0030] Within the scope of this invention, the laser device is preferably understood as a processing head connected to a laser or a means for providing a laser beam in order to transmit the laser beam, or the processing head having its own laser or a means for emitting a laser beam in order to transmit the laser beam. Within the scope of this invention, unless otherwise stated, the laser beam is understood as a segment of the laser beam output from the processing head in the direction of the processing area.

[0031] This invention is based on the understanding that in a laser apparatus with multiple processing heads (each of which outputs a laser beam), the relative positioning of the processing heads to each other must be set very precisely, while the absolute positioning of all the processing heads in the working area is less important. In equipment for additive manufacturing components, what is irrelevant to the component is whether it is manufactured at a predetermined position in the working area or slightly offset in this respect. However, it is very important that the individual segments of the component are precisely positioned relative to each other. Therefore, it is feasible to calibrate the laser apparatus using sensor plates and orifice gauges designed independently of the laser apparatus. During calibration, the sensor plates and orifice gauges are first inserted into the laser apparatus to pre-calibrate the sensor plates so that the relative positions of the sensor fields to each other are known. The orifice gauges can then be removed. During the calibration process, the sensor plates should maintain their precise position in the laser apparatus; however, how the sensor plates are positioned relative to the laser apparatus is secondary. Only the retention of the sensor plates' position during the calibration process is important so that the individual working heads can be precisely calibrated relative to each other.

[0032] The combination of a sensor plate with multiple sensor fields and an orifice gauge forms a very precise calibration device in a simple manner. The sensor plate with multiple sensor fields is typically a printed circuit board on which multiple area scanning cameras are arranged, each forming a sensor field. Due to the material, this printed circuit board is slightly warped. The deformation is primarily dependent on temperature. Therefore, the relative positioning of the sensor fields is not always very precise. By placing or positioning an orifice gauge with multiple calibration channels, only the areas of the sensor are initially used to calibrate the laser device, these areas being precisely aligned with each other in a precise location relationship due to the precise alignment of the calibration channels of the orifice gauge, wherein each calibration channel is arranged in one of the sensor fields. Therefore, by means of the orifice gauge, only the areas of the sensor fields that are precisely located relative to each other are initially accessible, allowing the relative positions of the sensor fields to be determined based on the location relationships known through the orifice gauge.

[0033] Because pre-calibration first determines the position of the sensor fields relative to each other, unlike the methods and devices described above in the prior art, laser beam calibration can be performed with the resolution provided by the sensor fields and is not bound to the diameter of the calibration opening. Since the sensor fields have pixels that are typically significantly smaller than the calibration opening, a resolution defined by the size of the pixels in the sensor field can be achieved. Therefore, the device can be used to accurately measure the location of the corresponding guide laser beam and the area of ​​the guide laser beam incident on the corresponding sensor field. This area can optimize the focusing of the guide laser beam.

[0034] If the laser device's working heads are thus calibrated using the sensor field area defined by the orifice gauge, then the working heads can be positioned precisely relative to each other. In other words, this means that the combination of the sensor plate and the orifice gauge forms a common, unified coordinate system to which all working heads are calibrated. Therefore, the coordinate system defined by the sensor plate and the orifice gauge can be referred to as the common principal coordinate system.

[0035] Specifically, it can be proposed that the diameter of the guiding laser beam is smaller than the corresponding correction opening. Since the location reference of the sensor field is known, the position of the guiding laser beam can be confirmed with a higher resolution than that determined by the diameter of the correction opening. Thus, the resolution is limited only by the size of the pixels in the sensor field, which is significantly smaller than the size of the correction channel opening in conventional camera chips (i.e., CMOS or CCD sensors). Therefore, the typical size of the pixels in the sensor field is no greater than 2μm × 2μm, and preferably no greater than 1.5μm × 1.5μm. The diameter of the correction opening is preferably at least 2mm, particularly at least 3mm or at least 5mm. Therefore, the area of ​​the correction opening includes a large number of pixels in the sensor field.

[0036] The sensor board is designed to be subjected to the same deformation as the building platform and / or components generated on the building platform due to the thermal effects of the working laser beam.

[0037] The orifice plate can be made of extremely stable or high-mechanical-strength materials, ensuring that the orifices do not change position even under thermal stress and are arranged precisely to achieve high accuracy. The calibration openings are mapped onto the sensor field of the sensor plate.

[0038] Therefore, according to the present invention, a guide laser beam is proposed for calibrating a working laser beam. A sensor plate is arranged on the working area of ​​the laser device, particularly on the build platform of an additive manufacturing apparatus. A perforated gauge is then arranged on the sensor plate. The sensor field of the sensor plate is then exposed via a calibration opening in the perforated gauge to determine the relative positions of the sensor fields. The guide laser beam is then positioned on the sensor field by means of the laser device based on control information through the calibration opening in the perforated gauge. Thus, the guide laser beam is directed onto the sensor field through multiple calibration openings, where the control information forms a target value. Now, multiple actual values ​​of the location information of the guide laser beam are detected by means of the sensor field. These actual values ​​are then compared with the corresponding target values ​​of the location information of different locations or positions of the guide laser beam, and the corresponding deviations are determined.

[0039] To control the laser device, the working laser beam is positioned within the working area using control information, wherein the deviation determined according to the invention is used as a correction value to determine the control information. A correction function can be generated based on a comparison of the actual and target values ​​of the location information of the working laser beam, so as to interpolate the determined value within the working area.

[0040] Furthermore, it can be proposed that all sensor fields are covered by orifice gauges, so that calibration openings are arranged in the region of each sensor field.

[0041] Therefore, a hole or a single hole plate gauge is provided for all sensor fields of a sensor plate or sensor device.

[0042] The sensor field can be arranged in the edge area of ​​the sensor board.

[0043] During use, the greatest deformation occurs in the working area or edge region of the build platform of the additive manufacturing equipment due to the heat energy introduced by the laser device. Therefore, it is sufficient to determine only the corresponding location in the edge region of the working area. This makes the equipment cost-effective.

[0044] Here, the corresponding sensor device in the sensor field can preferably detect the position with an accuracy of a few μ or even one μ.

[0045] Preferably, approximately 10 to 50 or 15 to 40, and particularly 20 to 30, sensor fields can be arranged on the sensor plate.

[0046] In addition, a laser device can be provided to provide the working laser beam.

[0047] The laser device may be, for example, a fiber laser. The laser may output laser power of at least 200 watts or at least 300 watts up to 400 watts or up to 600 watts or up to 800 watts or up to 1000 watts or up to 1200 watts.

[0048] The laser guiding device can be a component of the laser device or can be designed as a separate laser guiding device.

[0049] For example, a laser from IPG Photonics (commercially available as part number P21-010106, YLR series SLED3.0) can be used as a laser device. This laser beam can output a working laser beam and a guide laser beam.

[0050] The guiding laser beam is preferably designed as a focused laser beam and can have a power of approximately 0.1 watts.

[0051] For example, a guided laser beam can be formed by coupling a small amount of light into the laser generating device of the laser device, and / or by using a beam splitter, polarizing filter, beam blocker, deflector, or by providing a laser with an adjustable pump stage whose pump stage can be turned off.

[0052] Therefore, both the working laser beam and the guide laser beam can use the same optical fiber as the fiber laser.

[0053] Furthermore, the laser device has multiple processing heads connected to a common laser to transmit laser beams in a multiplexing manner. Alternatively, the laser device may also have multiple processing heads, each with its own laser (single positioning point). These two types of embodiments of laser devices with multiple processing heads for transmitting laser beams are referred to as multi-laser devices within the scope of this invention.

[0054] In this multi-laser setup, the lasers in each processing head are first referenced to their own coordinate systems in the X / Y plane; that is, each processing head is assigned a separate coordinate system. This means that each laser in the processing head has its own coordinate system.

[0055] By using the device according to the invention to correct the position or location of the lasers in the processing head, all lasers in the processing head can be referenced relative to a common principal coordinate system, such that the lasers are subsequently corrected relative to the common principal coordinate system in the working area.

[0056] During calibration, each processing head moves its laser beam to at least one, preferably multiple, points within its own reference coordinate system. These points are mapped to corresponding points in a unified principal coordinate system defined by the calibration device, thereby calibrating multiple lasers of a multi-laser device or multi-laser unit to the unified principal coordinate system. In this way, all lasers of the processing head can be aligned relative to the unified principal coordinate system.

[0057] Furthermore, the processing head can be aligned or configured such that each optical axis of the corresponding laser beam of the processing head extends perpendicularly to the working area or processing surface of the building platform. Because of the perpendicular laser beams, correction can be performed independently of the plane, allowing the distance between the processing head and the corresponding laser beam spacing to vary.

[0058] All optical axes of the multiple laser beams can be aligned perpendicular to the surface of the construction platform. This means that when the distance of the laser device from the sensor plate in the vertical direction (Z coordinate) changes, the position of the laser beam on the corresponding sensor field of the sensor plate or construction platform changes.

[0059] Additionally, a measuring device with a corresponding sensor for measuring the diameter of the laser beam can be provided. The diameter of the laser beam can be, for example, at least 30 μm, particularly at least 50 μm or at least 100 μm. Preferably, the diameter of the laser beam is no greater than 2 mm, particularly no greater than 1 mm or no greater than 500 μm.

[0060] It can not only calibrate one laser in the processing head of the laser device, but also calibrate and align multiple lasers in the laser device relative to each other.

[0061] Therefore, with the help of the present invention, not only can a laser device with one laser be calibrated in the processing area, but also multiple lasers of multiple processing heads can be calibrated in the corresponding processing area, so that multiple lasers of multiple processing heads of multiple laser devices can be calibrated relative to each other in the processing area.

[0062] The sensor device may include a printed circuit board and a CMOS sensor, and preferably an electronic network connection.

[0063] The edge of the orifice gauge's calibration channel opening limit can be sharp and / or tapered, such that the perforated plate is thin, at least in the region of the calibration channel opening.

[0064] This method can avoid parallax error.

[0065] The diameter of the calibration aperture can be approximately 4 to 5 mm smaller than the area of ​​the corresponding sensor field of the CMOS sensor.

[0066] The area of ​​the calibration channel opening can be smaller than the area of ​​the corresponding sensor field of the sensor device.

[0067] Specifically, the correction channel openings can be arranged in a grid or array with a spacing between 50 mm and 500 mm.

[0068] Since the area of ​​the calibration channel opening is smaller than the area of ​​the corresponding sensor field, the orifice gauge can be easily positioned.

[0069] The sensor plate and / or orifice gauge may have a centering device for centering the arrangement in the working area.

[0070] The working area is preferably a build platform for an additive manufacturing apparatus. Therefore, it is possible to propose that the sensor plate be centered and aligned on this build platform by means of a first centering device.

[0071] Then, the orifice plate can be calibrated onto the sensor plate using a second centering device.

[0072] A tube septum pointing in the direction of the laser device can be arranged on each of the calibration openings. This tube septum can be used to generate uniform diffuse light (dark field light) in the sensor field area.

[0073] Furthermore, according to the present invention, a system for calibrating a laser device is proposed, the system comprising, as shown above, an apparatus for calibrating the laser device and an apparatus for additive manufacturing, the apparatus having a plurality of processing heads for transmitting laser beams.

[0074] Within the scope of this invention, equipment for additive manufacturing is understood as equipment that uses a powder bed, powder conveying device, or wire conveying device to build a three-dimensional structure layer by layer, the powder bed, powder conveying device, or wire conveying device being used as a starting material and melted by means of a laser beam or also an electron beam or also by means of plasma or an electric arc. Therefore, equipment for additive manufacturing includes the generative manufacturing methods mentioned in the introduction of this specification (3D printing: melting and solidification (laser engineered net forming (LENS), direct metal deposition (DMD), or laser additive manufacturing (LAM)), local sintering or melting, (laser sintering (SLS)) metal laser sintering (DMLS), metal laser sintering (IMLS), electron beam melting (EBM), powder bed-based laser beam melting, laser powder bed fusion (LPBF), or laser deposition welding).

[0075] Furthermore, according to the present invention, a method for calibrating a laser device is proposed, which is suitable for freely positioning a working laser beam within a predetermined working area. The method can be used with the apparatus shown above to calibrate the laser device and includes the following steps:

[0076] Sensor boards are arranged on the working area, each containing multiple sensor fields.

[0077] An orifice gauge is arranged on a sensor plate, wherein the orifice gauge has a plurality of calibration holes arranged in a predetermined manner and respectively located in the region of the sensor field.

[0078] The sensor field of the sensor plate is exposed through the calibration opening of the orifice gauge in order to determine the relative positions of the sensor fields.

[0079] By using a laser device to position a guide laser beam onto a sensor field based on control information, the guide laser beam is directed onto multiple sensor fields. The control information used to position the guide laser beam forms a target value.

[0080] Multiple actual values ​​of location information guiding the laser beam are detected by a sensor field.

[0081] The actual value is compared with the corresponding target value based on location information of different locations or positions of the guiding laser beam, and

[0082] Determine the corresponding deviation.

[0083] The advantages of the method according to the invention are similar to those described above regarding the apparatus for calibrating a laser device. When calibrating a laser device, an orifice gauge can be arranged on a sensor plate. The sensor field is then freely accessible only in the area of ​​the calibration channel opening and can be used to calibrate the laser. However, it is preferable to remove the orifice gauge to calibrate the laser device, so that the entire sensor field is available for calibrating the laser device.

[0084] The sensor area can be exposed using a guided laser beam or other light source with a perforated gauge. A suitable light source is preferred, especially one that outputs diffuse light, such as a dark-field light source.

[0085] Specifically, it can be proposed that this method is designed for multiple lasers in a multi-laser processing head, wherein the following steps are performed:

[0086] Using a laser device, a guide laser beam is positioned onto the sensor field through the calibration opening of an orifice gauge based on control information, thus orienting the guide laser beam onto the sensor field. The control information forms the target value.

[0087] Multiple actual values ​​of location information guiding the laser beam are detected by a sensor field.

[0088] The actual value is compared with the corresponding target value for location information of different locations or positions of the guiding laser beam, and

[0089] Determine the corresponding deviations of each laser beam in the processing head, and

[0090] Multiple laser beams from a multi-laser head are aligned relative to each other in the processing area.

[0091] Furthermore, according to the present invention, a method for manipulating a laser beam is provided for the above-described system, wherein the working laser beam is positioned in a working area by means of control information. The method is characterized in that the control information is determined using the deviation determined above as a correction value.

[0092] Here, a correction function can be generated by comparing the actual value and the target value of the location information of the working laser beam, so that the determined correction value can be interpolated over the working area. Attached Figure Description

[0093] The invention will now be described in more detail with reference to the embodiments shown in the accompanying drawings. The drawings illustrate:

[0094] Figure 1 An exploded perspective view of a device for calibrating a laser apparatus according to the present invention is shown.

[0095] Figure 2 shows a schematic side view of the calibration opening of the orifice gauge of the device;

[0096] Figure 3 shows a schematic perspective view of the tube baffle for the calibration opening of the orifice gauge used in this device. Detailed Implementation

[0097] The apparatus 1 for calibrating a laser device according to the present invention will now be described in more detail. Figure 1 (See Figure 3). Device 1 is designed to freely position the working laser beam within a predetermined working area. The working area is preferably a build platform 2 of an additive manufacturing device (not shown).

[0098] Equipment 1 includes sensor plate 3 and orifice gauge 4.

[0099] Furthermore, device 1 includes a guiding laser device (not shown) for providing a guiding laser beam along the beam path of the working laser beam to calibrate the laser device. Preferably, the guiding laser device is an integral part of the laser device of the additive manufacturing device (not shown), or such laser device is designed to provide a guiding laser beam. Alternatively, the guiding laser device may also be a stand-alone laser device.

[0100] The sensor plate 3 has an approximately rectangular shape. In the current embodiment, twelve sensor devices with corresponding sensor fields 5 are arranged around the edge region of the sensor plate 3.

[0101] The sensor plate 3 is made of a material having a deformation that is substantially similar to the building platform of the equipment used for additive manufacturing, such as the corresponding additively manufactured part.

[0102] According to the design embodiment described, sensor fields 5 are arranged in the edge region of the sensor plate. Alternatively, other suitable numbers of sensor fields 5 or sensor devices can be used. For example, at least four, six, eight, ten, twelve, 14, 16, 18, 20, 22, 24, 26, 28, or 30 sensor fields can be provided, and a maximum of 32, 34, 36, 38, 40, 42, 44, 46, 48, or 50 sensor fields 5 can be provided. Alternatively, the individual sensor fields 5 can also be arranged in a grid or array with approximately the same spacing between them.

[0103] The sensor board 3 is composed of a printed circuit board, wherein the sensor device or sensor field 5 is composed of a CMOS sensor.

[0104] In addition, sensor board 3 has a network connection (not shown) for connecting to a corresponding data network.

[0105] The sensor plate 3 has a centering device (not shown), such as by means of pins, to center the sensor plate on the working area or the construction platform 2. This secures the sensor plate to the laser device during the calibration process.

[0106] The orifice gauge 4 also has a generally rectangular shape. Furthermore, calibration openings 6 are formed in the orifice gauge 4, the number of which corresponds to the number of sensor fields 5 on the sensor plate 3. Therefore, the calibration openings 6 are arranged in the orifice gauge 4 corresponding to the positions of the sensor fields 5 on the sensor plate 3.

[0107] The orifice gauge 4 is made of a material with high inherent rigidity or a very stable material, and further, a material with high mechanical strength, so that the orifice gauge 4 does not deform or hardly deforms when heat is applied. This is very advantageous because the correction opening 6 is then always arranged in the same location or position relative to the construction platform.

[0108] In use, the corresponding calibration opening 6 of the orifice gauge 4 is mapped onto the sensor field 5 of the sensor plate 3.

[0109] Each of the sensor fields 5 is assigned at least one calibration opening 6 of the orifice gauge 4, such that the calibration opening 6 is arranged in the region of each sensor field 5.

[0110] The edge or boundary of the calibration opening 6 of the orifice gauge 4 is sharp or thin, so that parallax error can be avoided.

[0111] Additionally and / or alternatively, the calibration opening 6 of the orifice gauge 4, or the edge of the calibration opening 6, may be tapered in the direction toward the sensor field 5 in order to similarly avoid parallax error (Figure 2).

[0112] The area of ​​the calibration opening 6 is smaller than the area of ​​the corresponding sensor field 5 so that it is completely covered by the corresponding sensor field 5. In this way, the calibration opening 6 can be easily positioned or aligned according to the sensor field 5 of the sensor plate 3.

[0113] Additionally, a tube septum 7 pointing towards the laser device can be arranged on each of the correction openings 6 (Fig. 3). With the aid of the tube septum 7, uniform diffuse light (dark field light) can be generated in the region of the sensor field 5.

[0114] The system for calibrating a laser device (not shown) according to the present invention includes the apparatus 1 for calibrating the laser device shown above and an apparatus for additive manufacturing. The additive manufacturing apparatus may be a corresponding apparatus to one of the additive manufacturing methods indicated above. Such an apparatus includes a plurality of processing heads for transmitting laser beams, respectively.

[0115] Furthermore, according to the present invention, a method for calibrating a laser device designed to freely position a working laser beam within a predetermined working area is provided. This method uses the aforementioned device 1 to calibrate the laser device.

[0116] The method includes the following steps:

[0117] First, the sensor plate 3 is placed on the work area, specifically on the build platform 2 of the additive manufacturing equipment (S1). The sensor plate is aligned and centered on the build platform using a centering device.

[0118] Then, the orifice gauge 4 is arranged on the sensor plate 3, wherein the orifice gauge 4 has a plurality of calibration openings 6, which are arranged relative to each other in a predetermined arrangement (S2).

[0119] Now, the sensor field 5 is exposed. The exposure is performed via the calibration opening 6 of the orifice gauge 4 to determine the relative position of the sensor fields 5 relative to each other (S3). Here, the complete calibration opening 6 is mapped onto the corresponding sensor field 5.

[0120] Then, using a laser device based on control information, the guide laser beam is positioned on the sensor field through the calibration opening 6 of the orifice gauge 4 (S4). In this way, the guide laser beam is directed onto the sensor field through multiple calibration channel openings 6. The corresponding control information forms the target value.

[0121] Then, sensor field 5 is used to detect multiple actual values ​​of the location information guiding the laser beam (S5).

[0122] Finally, the actual value is compared with the target value corresponding to the location information of different locations or positions of the guiding laser beam (S6).

[0123] Based on the value, the corresponding deviation between the target value and the actual value can be determined (S7).

[0124] Furthermore, this invention proposes a method for controlling a laser beam using the system described above, wherein the working laser beam is positioned in the working area using control information. To determine the control information, a deviation determined by a method for correcting the laser device is used as a correction value.

[0125] A correction function is generated by comparing the actual and target values ​​of the working laser beam's location information. The correction function can then interpolate the calculated values ​​over the working area.

[0126] Instead of equipment used for additive manufacturing, the equipment according to the invention can also be configured, for example, to correct the laser beam used in laser cutting equipment, etc.

[0127] The key components of laser cutting equipment or laser beam cutting machines are the laser beam source, the laser beam guide, and the processing head (focusing optics) including the cutting nozzle. The laser beam exiting the laser beam source can be guided at the processing location via an optical cable in the near-infrared (Nd:YAG laser, fiber laser, disk laser) or via a deflector relative to the focusing optics in the case of a CO2 laser. The focusing optics concentrate the laser beam at a focal point, thereby producing the intensity required for cutting.

[0128] Systems with CO2 lasers typically consist of a fixed laser beam source and so-called flying optics. A reflecting telescope, positioned over the entire processing area, ensures a constant original beam diameter on the focusing lens. This is necessary because the beam emitted from the laser has a fixed divergence. Different beam lengths at different processing locations, without compensation via the reflecting telescope, will alter the original beam diameter on the lens. This will result in variations in the number and intensity of apertures.

[0129] If needed, beam guidance between the optical resonator (laser beam source) and the focusing optics is achieved via a water-cooled mirror. The mirror is coated with gold or molybdenum and constructed of single-crystal silicon or pure copper. On the other hand, laser radiation with wavelengths in the range of approximately 1 μm (Nd:YAG lasers, fiber lasers, disk lasers) can also be guided over long distances using optical cables.

[0130] To obtain direction-independent cutting quality, a phase rotating mirror is placed between the resonator and the telescope in the case of a linearly polarized laser beam.

[0131] The beam is focused through a so-called cutting nozzle, which is typically made of copper and also deflects the blowing gas or process gas onto the processing area.

[0132] List of reference numerals

[0133] 1 device

[0134] 2. Building a Platform

[0135] 3 sensor board

[0136] 4-hole plate gauge

[0137] 5 sensor field

[0138] 6. Correction opening

[0139] 7-tube baffle.

Claims

1. An apparatus for calibrating a laser device, the apparatus being designed to freely position a working laser beam within a predetermined working area, the apparatus comprising: A sensor board having multiple sensor fields, the sensor board being arranged in a working area; An orifice gauge has multiple calibration openings, each of which is disposed in one of the sensor fields, and the surface of each calibration opening is smaller than the surface of the corresponding sensor field of the sensor plate. A control device is configured to determine the relative position of the sensor fields in a common principal coordinate system after the sensor fields have been exposed through the calibration opening of the orifice gauge. A guiding laser device is provided to provide a guiding laser beam along the path of the working laser beam to calibrate the laser device by scanning the guiding laser beam through the sensor field according to the relative position of the sensor field in the common principal coordinate system.

2. The device according to claim 1, Its features are, All sensor fields are covered by the orifice gauge, such that the calibration opening is provided in the region of each sensor field.

3. The device according to claim 1, Its features are, The sensor field is arranged in the edge region of the sensor plate.

4. The device according to claim 1, Its features are, The laser device is designed to provide the working laser beam.

5. The device according to claim 4, Its features are, The guiding laser device is either a component of the laser device or designed as a separate guiding laser device.

6. The device according to claim 1, Its features are, The sensor board includes at least one of a printed circuit board, a CMOS sensor, and a CCD sensor.

7. The device according to claim 6, Its features are, The sensor board includes electronic network connections.

8. The device according to claim 1, Its features are, The edge of the orifice gauge with the correction opening as its boundary is at least one of a thin angle shape and a tapered shape, such that the orifice gauge is thin in at least one region of the correction opening to avoid parallax error.

9. The device according to claim 1, Its features are, The correction openings are arranged in a grid pattern with a spacing between 50 mm and 500 mm.

10. The device according to claim 1, Its features are, At least one of the sensor plate and the orifice gauge has a centering arrangement device for centering the sensor plate in the working area.

11. The device according to claim 1, Its features are, Each of the correction openings is provided with a tube septum facing the direction of the laser device to generate uniform diffuse light in the region of the sensor field.

12. A system for calibrating a laser device, comprising: The apparatus for calibrating the laser device and the apparatus for manufacturing additive materials, as described in claim 1, The equipment used to manufacture the additive material includes multiple processing heads, each of which emits a respective laser beam.

13. A method for calibrating a laser device, the method being adapted to freely position a working laser beam within a predetermined working area using the apparatus for calibrating a laser device according to claim 1, the method comprising the steps of: A sensor board is arranged on the working area, wherein the sensor board has multiple sensor fields. An orifice gauge is arranged on the sensor plate, wherein the orifice gauge has a plurality of calibration openings, which are respectively arranged in a predetermined arrangement relative to each other in a region of the sensor field. The sensor field of the sensor plate is exposed through the calibration opening of the orifice gauge to determine the relative positions of the sensor fields to each other in a common principal coordinate system. The laser device, based on control information, positions a guide laser beam onto the sensor field, thereby orienting the guide laser beam onto multiple sensor fields. The control information used to position the guide laser beam forms a target value. Multiple actual values ​​of the location information of the guiding laser beam are detected by means of the sensor field based on the relative position of the sensor field in the common principal coordinate system. The actual value is compared with the target value corresponding to the location information of different locations of the guiding laser beam, and Determine the corresponding deviation.

14. The method according to claim 13, Its features are, The determined deviation is used as a correction value to determine the control information used to position the working laser beam.

15. The method according to claim 14, Its features are, A correction function is generated by comparing the actual value and the target value of the location information of the working laser beam, and the determined value is interpolated over the working area.

16. The method according to claim 13, Its features are, The method is designed for multiple laser beams from a processing head using a multi-laser device, wherein the following further steps are performed. Determine each of the deviations of the individual laser beams in the plurality of laser beams of the processing head, and In the processing area, the multiple laser beams of the processing head of the multi-laser device are aligned relative to each other.

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