Method and device for producing an object by additive manufacturing

Abstract

The method for producing an object by additive manufacturing comprises the following steps: - determining a characteristic of a beam of electromagnetic radiation at a first position of the beam of electromagnetic radiation by a first determination unit and, preferably, simultaneously determining said characteristic of the beam of electromagnetic radiation at a second position by a second determination unit; - calibrating said second determination unit by said control unit taking into account said characteristic of the beam of electromagnetic radiation determined by said first determination unit. Apparatus for producing an object by additive manufacturing.

Description

Technical Field

[0001] According to a first aspect, the present disclosure relates to a method for producing an object by additive manufacturing using an apparatus.

[0002] According to a second aspect, the present disclosure relates to an apparatus for manufacturing an object by additive manufacturing. Background Art

[0003] 3D printing or additive manufacturing refers to any of a number of different processes for making three-dimensional objects, in which materials are combined or solidified under computer control to create a three-dimensional object, usually by adding materials together layer by layer. Traditional techniques such as injection molding may be cheaper for making, for example, large quantities of polymer products, but 3D printing or additive manufacturing can be faster, more flexible, and cheaper when producing relatively small quantities of three-dimensional objects.

[0004] Three-dimensional objects can be produced by selectively solidifying powdered materials in a layered manner to produce three-dimensional (3D) objects. In particular, computer-controlled additive manufacturing equipment can be used, which sequentially sinter multiple layers to build the desired object in a layer-by-layer manner. Additive processes are mainly used, in which successive layers of material are laid down under computer control. These objects can be of almost any shape or geometry and are generated from 3D models or other electronic data sources.

[0005] For example, to print a three-dimensional object, a printable model is created by a computer design package or by a 3D scanner. Typically, the input is a 3D CAD file, such as an STL file, a STEP file, or an IGS file. Before the object is printed from the CAD file, the file is processed by software that converts the model into a series of thin sequential layers. In addition, device settings and vectors are generated to control the creation of each layer of the sequential layers.

[0006] The curing device (preferably a laser) included in the computer-controlled additive manufacturing equipment follows these settings and vectors to cure successive layers of material to build a 3D object from a series of cross sections. These layers corresponding to the virtual cross sections from the CAD model are simultaneously combined or fused during this process to create the final 3D object.

[0007] Known systems for printing three-dimensional objects include:

[0008] a processing chamber for receiving a molten pool of powdered material capable of being solidified by exposure to electromagnetic radiation;

[0009] a support for horizontally positioning the object relative to a surface of a melt pool of powdered material;

[0010] curing means arranged to emit a beam of electromagnetic radiation on said horizontal surface for curing selective portions of said powder material; and

[0011] A control unit is used to control the device.

[0012] One of the challenges of known systems, in particular for producing metal objects by additive manufacturing, is how to further improve the quality of the manufactured objects while achieving a relatively large manufacturing output. Summary of the invention

[0013] The object of the present disclosure is to provide an apparatus and a method for producing an object by additive manufacturing, which apparatus and method allow improving the quality of the manufactured object while achieving a relatively large manufacturing output.

[0014] This object is achieved by using a device according to the method of the present disclosure, the device comprising:

[0015] a first determining unit for determining a characteristic of the beam of electromagnetic radiation at a first position of the beam of electromagnetic radiation;

[0016] A second determination unit, the second determination unit is used to determine the characteristics of the beam of electromagnetic radiation at a second position, wherein the second position is relative to the first position and is related to a position shifted along the beam of electromagnetic radiation toward the curing device during use, or wherein the second position is along another beam of electromagnetic radiation, wherein the other beam of electromagnetic radiation is separated from the beam of electromagnetic radiation.

[0017] By setting a first determination unit, the characteristics of the beam of electromagnetic radiation can be determined at a first position. For this purpose, the first determination unit is arranged and positioned to determine the characteristics of the beam of electromagnetic radiation at the first position of the beam of electromagnetic radiation. In other words, the first determination unit is arranged and positioned so that the characteristics of the beam of electromagnetic radiation at the first position of the beam of electromagnetic radiation are determinable. The first position can, for example, be positioned at a position related to the horizontal surface of the molten pool of the powder material. The first position can, for example, be set at the same height as the height of the horizontal surface of the molten pool of the powder material in the processing chamber. Such a first position is conducive to obtaining information about the beam of electromagnetic radiation, wherein the characteristics at the first position can be equal to or at least very similar to the characteristics of the beam of electromagnetic radiation at the position of solidifying the powder material during the actual process of solidifying the powder material when producing the object.

[0018] The present disclosure relies at least in part on the insight that determining the characteristics of a beam of electromagnetic radiation at a processing position where a powder material is solidified during a process of manufacturing the object can be advantageous for achieving a relatively high product quality. Taking into account the characteristics determined by a first determination unit, for example, a curing device can be actively controlled to correct for changes in the characteristics of the beam of electromagnetic radiation detected during the manufacturing process. However, this first position may not be conducive to achieving a relatively large manufacturing output. For example, the first position may require moving the beam of electromagnetic radiation away from the processing position and thereby interrupting the interaction of the beam of electromagnetic radiation with the powder material, thereby increasing processing time and potentially having a negative impact on product quality.

[0019] By setting a second determination unit, the characteristic of the beam of electromagnetic radiation can be determined at a second position of the beam of electromagnetic radiation. For this purpose, the second determination unit is arranged and positioned to determine the characteristic of the beam of electromagnetic radiation at the second position of the beam of electromagnetic radiation. In other words, the second determination unit is arranged and positioned so that the characteristic of the beam of electromagnetic radiation at the second position of the beam of electromagnetic radiation is determinable. The second position can be related to a position shifted toward the curing device along the beam of electromagnetic radiation in use, or to a position along another beam of electromagnetic radiation relative to the first position, wherein the other beam of electromagnetic radiation is separated from the beam of electromagnetic radiation. In this way, the characteristic can be determined during the manufacturing process of the material without interrupting the manufacturing process. The second determination unit is conducive to allowing a relatively large manufacturing output while determining the characteristic of the beam of electromagnetic radiation.

[0020] A disadvantage of determining the characteristic of the beam of electromagnetic radiation at the second position is that the value of the characteristic determined, for example, by the second determination unit, may be different from the values ​​of the characteristic, for example, at the first position and at the processing position. The method according to the first aspect of the present disclosure overcomes this disadvantage in that the method comprises the following steps:

[0021] a step of determining, by means of said first determining unit, said characteristic of said beam of electromagnetic radiation at said first position of said beam of electromagnetic radiation and, preferably, simultaneously, by means of said second determining unit, said characteristic at said second position;

[0022] A calibration step of calibrating, by means of the control unit, the second determination unit taking into account the characteristic of the beam of electromagnetic radiation determined by the first determination unit.

[0023] By determining the characteristic of the beam of electromagnetic radiation at the first position and the second position and calibrating the second determination unit taking into account the characteristic of the beam of electromagnetic radiation determined by the first determination unit, a relatively high quality of the manufactured object can be obtained while achieving a large manufacturing output. By calibrating the second determination unit using the measurement results of the first determination unit, a value of the characteristic can be obtained by the second determination unit, which value correlates relatively well with the value of the characteristic at the first position.

[0024] Preferably, the control unit is communicatively coupled to the first determination unit and to the second determination unit for said calibration.

[0025] Preferably, the first determining unit and the second determining unit determine the characteristic of the beam of electromagnetic radiation simultaneously. This is advantageous for achieving a relatively high correlation factor between, for example, the value of the characteristic determined by the first determining unit and the value of the characteristic determined by the second determining unit.

[0026] In an embodiment, the characteristic is at least one of power, caustics and focus position of the beam of electromagnetic radiation.

[0027] Advantageously, the method further comprises the following steps:

[0028] A shifting step, before performing said determining step, shifting said beam of electromagnetic radiation relative to said first determining unit by means of a shifting unit.

[0029] Displacing the beam of electromagnetic radiation advantageously allows determining the characteristic at a relatively practical position inside the apparatus. For example, the first position may be selected such that the first determination unit is not affected by, or is affected only to a limited extent by, environmental conditions present in the process chamber. For example, the first determination unit may be maintained in a position wherein the temperature is controlled to a level that is advantageous for the first determination unit.

[0030] In a very practical embodiment of the method according to the first aspect of the present disclosure, said second determination unit is arranged for detecting said characteristic of said beam of electromagnetic radiation at said second position during said manufacturing of said object,

[0031] Wherein, the method further comprises the following steps:

[0032] a control step of controlling said curing means by said control unit taking into account the detected characteristics of said beam of electromagnetic radiation at said second location during said manufacturing of said object;

[0033] Wherein, the controlling step is performed after the calibrating step.

[0034] During production, controlling the curing device taking into account the detected characteristic is advantageous in that it compensates for changes in the characteristic that may occur during production of the object and thereby achieves a relatively high product quality.

[0035] Preferably, during said controlling step, said curing device is controlled such that said characteristic of said beam of electromagnetic radiation remains substantially constant. This facilitates achieving a relatively constant curing process during manufacture of the object and thereby achieving a relatively high product quality.

[0036] It is advantageous if the device comprises a measuring chamber accommodating the first determination unit. The measuring chamber is advantageous for enabling the first determination unit to be in favorable environmental conditions. The measuring chamber can, for example, be maintained in a predetermined temperature range that is favorable for the first determination unit.

[0037] Preferably, the measuring chamber is separate from the processing chamber. A measuring chamber separate from the processing chamber is advantageous in that the first determination unit is not affected by the environmental conditions existing in the processing chamber or is affected by the environmental conditions existing in the processing chamber only to a limited extent.

[0038] In this respect, it is advantageous if, during the displacement step, the beam of electromagnetic radiation is displaced by the displacement unit displacing the curing device relative to the first determination unit. This advantageously allows the measurement chamber to be arranged at a relatively large distance from the process chamber, thereby achieving that the first determination unit can be exposed to favorable environmental conditions.

[0039] It is advantageous if the first position is such that the value of the characteristic of the beam of electromagnetic radiation determined by the first determination unit is an absolute measure of the characteristic of the beam of electromagnetic radiation at the horizontal surface. This advantageously allows a comparison of the characteristics of beams of electromagnetic radiation from different curing devices of a single apparatus or of beams of electromagnetic radiation from different curing devices of different apparatuses.

[0040] Preferably, the apparatus comprises a plurality of the curing devices and a corresponding plurality of the second determining units, wherein each of the second determining units is associated with a curing device of the plurality of curing devices to determine the characteristic of the beam of electromagnetic radiation emitted from the corresponding curing device in use; wherein the method comprises the following steps:

[0041] for each of the curing devices, determining by means of the first determining unit the characteristic of the beam of electromagnetic radiation at the first position of the beam of electromagnetic radiation and, preferably, simultaneously determining by means of the corresponding second determining unit the characteristic of the beam of electromagnetic radiation at the second position;

[0042] Each of the corresponding second determination units is calibrated by the control unit taking into account the characteristic of the beam of electromagnetic radiation determined by the first determination unit.

[0043] Alternatively, the second determination unit is arranged for determining another characteristic related to the characteristic of the beam of electromagnetic radiation at a second position, wherein the second position is related to a position shifted along the beam of electromagnetic radiation towards the curing device during use relative to the first position, or wherein the second position is along another beam of electromagnetic radiation, wherein the another beam of electromagnetic radiation is separated from the beam of electromagnetic radiation.

[0044] Preferably, said another characteristic is at least one of power, caustics and focus position of said beam of electromagnetic radiation.

[0045] Preferably, the solidification device comprises the second determining unit.

[0046] In another embodiment of the method for producing an object by additive manufacturing using an apparatus according to the first aspect of the present disclosure, the apparatus comprises:

[0047] the processing chamber for receiving a molten pool of the powdered material capable of being solidified by exposure to electromagnetic radiation;

[0048] the support for positioning the object relative to a horizontal surface of a molten pool of the powder material;

[0049] the curing device being arranged for emitting a beam of electromagnetic radiation onto the horizontal surface for curing a selective portion of the powder material; wherein the curing device comprises a second determining unit for determining the characteristic of the beam of electromagnetic radiation at the second position,

[0050] the first determining unit for determining the characteristic of the beam of electromagnetic radiation at the first position of the beam of electromagnetic radiation; and

[0051] The control unit is used to control the device;

[0052] Wherein, the method comprises the following steps:

[0053] a step of determining, by means of said first determining unit, said characteristic of said beam of electromagnetic radiation at said first position of said beam of electromagnetic radiation and, preferably, simultaneously, by means of said second determining unit, said characteristic at said second position;

[0054] A calibration step of calibrating, by means of the control unit, the second determination unit taking into account the characteristic of the beam of electromagnetic radiation determined by the first determination unit.

[0055] According to a second aspect, the present disclosure relates to an apparatus for manufacturing an object by additive manufacturing, the apparatus comprising:

[0056] a processing chamber for receiving a molten pool of powdered material capable of being solidified by exposure to electromagnetic radiation;

[0057] a support for positioning the object relative to a horizontal surface of a molten pool of powdered material;

[0058] a curing device arranged to emit a beam of electromagnetic radiation onto the horizontal surface for curing a selective portion of the powder material;

[0059] a first determining unit for determining, in use, a characteristic of the beam of electromagnetic radiation at a first position of the beam of electromagnetic radiation;

[0060] a second determining unit for determining, in use, said characteristic of said beam of electromagnetic radiation at a second position, wherein said second position is displaced relative to said first position, in use, along said beam of electromagnetic radiation towards said curing device, or wherein said second position is along another beam of electromagnetic radiation, wherein said another beam of electromagnetic radiation is separated from said beam of electromagnetic radiation; and

[0061] A control unit is arranged to calibrate the second determining unit taking into account the characteristic of the beam of electromagnetic radiation determined in use by the first determining unit.

[0062] Embodiments of the device according to the second aspect correspond to embodiments of the method according to the first aspect of the disclosure. The advantages of the device according to the second aspect correspond to the previously presented advantages of the method according to the first aspect of the disclosure.

[0063] Preferably, the first determining unit and / or the second determining unit is arranged to determine at least one of the following:

[0064] The power, caustics and focus position of the beam of electromagnetic radiation.

[0065] Preferably, the first determination unit is arranged and positioned for determining a characteristic of the beam of electromagnetic radiation at the first position of the beam of electromagnetic radiation. In other words, the first determination unit is arranged and positioned such that a characteristic of the beam of electromagnetic radiation at the first position of the beam of electromagnetic radiation is determinable.

[0066] Preferably, the second determination unit is arranged and positioned for determining a characteristic of the beam of electromagnetic radiation at the second position of the beam of electromagnetic radiation. In other words, the second determination unit is arranged and positioned such that a characteristic of the beam of electromagnetic radiation at the second position of the beam of electromagnetic radiation is determinable.

[0067] It is advantageous if the device comprises a displacement unit arranged for displacing the beam of electromagnetic radiation relative to the first determination unit. Providing a displacement unit facilitates displacing the beam of electromagnetic radiation relative to the first determination unit and thereby allows determining the characteristic at a relatively practical position inside the device. For example, the first position may be chosen such that the first determination unit is not affected by environmental conditions present in the process chamber, or is affected only to a limited extent by environmental conditions present in the process chamber. For example, the first determination unit may be maintained in a position wherein the temperature is controlled to a level that is advantageous for the first determination unit.

[0068] Preferably, the device comprises a measuring chamber accommodating the first determination unit. This is advantageous in that the first determination unit can be placed in favorable environmental conditions. The measuring chamber can, for example, be maintained within a predetermined temperature range favorable to the first determination unit.

[0069] In this regard, it is advantageous if the measuring chamber is separate from the process chamber. A measuring chamber separate from the process chamber facilitates the realization that the first determination unit is not influenced or is influenced only to a limited extent by the ambient conditions prevailing in the process chamber.

[0070] In this regard, it is advantageous if the displacement unit is arranged to displace the curing device relative to the first determination unit. This advantageously allows the measurement chamber to be arranged at a relatively large distance from the process chamber, thereby enabling the first determination unit to be exposed to favorable environmental conditions.

[0071] Preferably, the first position is such that a value of the characteristic of the beam of electromagnetic radiation determined by the first determination unit in use of the device is an absolute measure of the characteristic of the beam of electromagnetic radiation at the horizontal surface.

[0072] In an embodiment of the device according to the second aspect, the second position is such that the characteristic of the beam of electromagnetic radiation is determinable at the second position during the manufacture of the object. Determining the characteristic at the second position during manufacture is advantageous for allowing: during manufacture of the object, taking into account the detected characteristic, controlling the curing device in order to compensate for changes in the characteristic that may occur during manufacture of the object and thereby achieving a relatively high product quality

[0073] Preferably, the solidification device comprises the second determining unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Next, the device and method according to the present disclosure will be explained by means of the accompanying drawings. In the drawings:

[0075] Figure 1 : shows a schematic overview of an apparatus according to the second aspect of the present disclosure.

[0076] Figure 2 : shows a schematic overview of another system according to the second aspect of the present disclosure.

[0077] Figure 3 : shows a schematic overview of the method according to the first aspect of the present disclosure;

[0078] Figure 4 : shows a schematic overview of another method according to the first aspect of the present disclosure. DETAILED DESCRIPTION

[0079] Figure 1 An overview of an apparatus 1 for producing an object 2 by additive manufacturing is shown. The apparatus 1 consists of a plurality of frame parts 11, 12, 13. The apparatus comprises a processing chamber 3 for receiving a bath of a material 4 capable of being solidified. In the lower frame part 11 an axis is formed, in which a support 5 is arranged for positioning an object 2 (or even a plurality of objects) relative to a horizontal surface L of the bath of the material 4. The support 5 is movably arranged in the axis so that after solidification of a layer, the support 5 can be lowered and another layer of material can be solidified on top of an already formed part of the object 2. In the top part 13 of the apparatus 1 a solidification device 7 is arranged for solidifying a selective part of the material 4. In the embodiment shown, the solidification device 7 is a laser device arranged for generating electromagnetic radiation in the form of a laser to melt a powder material 4 provided on the support 5, which then forms a solidified part of the object 2 to be produced after cooling. However, the invention is not limited to this type of solidification device. It can be seen that the electromagnetic radiation 9 emitted by the laser device 7 is deflected by means of a displacement unit comprising a deflector unit 15 which uses a rotatable optical element 17 to direct the emitted radiation 9 towards the surface L of the layer of material 4. Depending on the position of the deflector unit 15, radiation can be emitted according to rays 19, 21, for example.

[0080] The device 1 further comprises a first determination unit 23, a second determination unit 25 and a control unit 31. The first determination unit 23 may, for example, comprise a detector for detecting the power, the caustics and / or the focus position of the beam of electromagnetic radiation 9 at a first position. The first position corresponds to the height of the horizontal surface L. The first determination unit 23 is arranged in a measuring chamber 33. The measuring chamber 33 is arranged close to the process chamber 3 and preferably the measuring chamber 33 is at least partially thermally decoupled from the process chamber 3. Instead of or in addition to the thermal decoupling, the measuring chamber 33 may be coupled to a regulating device (not shown) for regulating the receiving space of the measuring chamber 33, thereby maintaining the first determination unit 23 in a conditioned environment. Maintaining the first determination unit 23 in a conditioned environment is advantageous for reducing measurement errors caused by the first determination unit 23 when determining the characteristics of the beam of electromagnetic radiation 9.

[0081] The second determination unit 25 is arranged at a second position. The second position is displaced relative to the first position in use along the beam of electromagnetic radiation 9 towards the curing device 7. The second determination unit 25 may for example comprise a detector for detecting the power, caustics and / or focus position of the beam of electromagnetic radiation 9. Alternatively, the curing device 7 may comprise the second determination unit 25.

[0082] The control unit 31 is communicatively coupled to the first determination unit 23, the second determination unit 25 and the curing device 7. Communicatively coupling both the first determination unit 23 and the second determination unit 25 to the control unit 31 facilitates calibrating the second determination unit 25 by the control unit 31 taking into account the characteristics of the beam of electromagnetic radiation 9 determined by the first determination unit 23.

[0083] The device 101 mainly differs from the device 1 in that the second position is along the further beam of electromagnetic radiation 10, wherein the further beam of electromagnetic radiation 10 is separated from the beam of electromagnetic radiation 9. Positioning the second position along the further beam of electromagnetic radiation 10 allows detecting the characteristics of the beam of electromagnetic radiation at the second position during the manufacturing of the object 2, while reducing or at least minimizing any disturbance caused by the second determination unit 25 on the beam of electromagnetic radiation 9. Elements of the device 101 that are similar to elements of the device 1 are provided with the same reference numerals as the elements in the device 1.

[0084] The method 201 comprises a shifting step 207 of shifting the beam of electromagnetic radiation 9 relative to the first determination unit 23 by means of the shifting unit 15. During this shifting step 207, the beam of electromagnetic radiation 9 is deflected towards the first determination unit 23 by means of the deflector unit 15 so that the beam of electromagnetic radiation 9 impinges on the first determination unit 23 for determining the characteristic of the beam of electromagnetic radiation 9.

[0085] The method 201 further comprises a determination step 203 of determining, by the first determination unit 23, the characteristic of the beam of electromagnetic radiation 9 at the first position of the beam of electromagnetic radiation 9. During the determination step 203, the second determination unit 25 also determines the characteristic at the second position.

[0086] After determining said characteristics of said beam of electromagnetic radiation 9 at said first position and said second position, a calibration step 205 is performed by said control unit 31. During said calibration step 205, said second determination unit 25 is calibrated taking into account said characteristics of said beam of electromagnetic radiation 9 determined by said first determination unit 23. In other words, the output of said second determination unit 25 is converted into the output of said first determination unit 23.

[0087] During the manufacturing of the object 2, the calibrated second determination unit 25 may be used during a control step 209. During the control step 209, the curing device 7 is controlled by the control unit 31 taking into account the detected characteristic of the beam of electromagnetic radiation 9 at the second position. Preferably, during the control step 209, the curing device 7 is controlled such that the characteristic of the beam of electromagnetic radiation 9 remains substantially constant.

[0088] The method 301 differs from the method 201 mainly in that the characteristic of the beam of electromagnetic radiation 9 is determined by the second determination unit 25 during a further determination step 211. The characteristic at the first position and the characteristic at the second position are determined during two different steps 203 and 211. Steps of the method 301 that are similar to steps of the method 201 are provided with the same reference numerals as the steps in the method 201.

Claims

1. A method (201, 301) for producing an object (2) by additive manufacturing using an apparatus (1, 101), the apparatus (1, 101) comprising: a processing chamber (3) for receiving a molten pool of powdered material (4) capable of being solidified by exposure to electromagnetic radiation; a support (5) for positioning the object (2) relative to a horizontal surface (L) of a molten pool of the powder material (4); a curing device (7) arranged to emit a beam of electromagnetic radiation (9) onto the horizontal surface (L) for curing a selective portion of the powder material (4); a first determination unit (23) arranged and positioned for determining a characteristic of the beam of electromagnetic radiation (9) at a first position of the beam of electromagnetic radiation (9); a second determination unit (25) arranged and positioned for determining a characteristic of the beam of electromagnetic radiation (9) at a second position, the second determination unit being arranged for detecting the characteristic of the beam of electromagnetic radiation at the second position during manufacture of the object, wherein the second position is related to a position displaced in use along the beam of electromagnetic radiation (9) towards the curing device (7) relative to the first position, or wherein the second position is along another beam of electromagnetic radiation, wherein the another beam of electromagnetic radiation is separated from the beam of electromagnetic radiation (9), the curing device comprising the second determination unit; and A control unit (31), the control unit (31) being used to control the device (1, 101); The method (201, 301) comprises the following steps: a determination step (203), determining the characteristic of the beam of electromagnetic radiation (9) at the first position of the beam of electromagnetic radiation (9) by means of the first determination unit (23), and determining the characteristic at the second position by means of the second determination unit (25); a calibration step (205) of calibrating the second determination unit (25) by means of the control unit (31) taking into account the characteristics of the beam of electromagnetic radiation (9) determined by the first determination unit (23), A control step (209) of controlling the curing device by means of the control unit taking into account the detected properties of the beam of electromagnetic radiation at the second position during the manufacture of the object, wherein the control step is performed after the calibration step.

2. The method (201, 301) according to claim 1, wherein: The characteristic is at least one of power, caustics and focus position of the beam of electromagnetic radiation.

3. The method (201, 301) according to claim 1 or 2, wherein: The method (201, 301) further comprises the following steps: A shifting step (207) of shifting the beam of electromagnetic radiation (9) relative to the first determining unit (23) by means of a shifting unit (15) before performing the determining step.

4. The method (201, 301) according to claim 1, wherein: During the controlling step, the curing device is controlled such that the characteristic of the beam of electromagnetic radiation remains substantially constant.

5. The method (201, 301) according to claim 1 or 2, wherein: The device comprises a measuring chamber (33) accommodating the first determination unit (23).

6. The method (201, 301) according to claim 5, wherein: The measuring chamber (33) is separated from the processing chamber (3).

7. The method (201, 301) according to claim 1 or 2, wherein: The first position is such that the value of the characteristic of the beam of electromagnetic radiation determined by the first determination unit is an absolute measure of the characteristic of the beam of electromagnetic radiation at the horizontal surface.

8. The method (201, 301) according to claim 1 or 2, wherein: The apparatus comprises a plurality of said curing devices and a corresponding plurality of said second determining units, wherein each of said second determining units is associated with a curing device of said plurality of curing devices for determining said characteristic of said beam of electromagnetic radiation emitted from the corresponding said curing device in use; Wherein, the method comprises the following steps: for each of the curing devices, determining the characteristic of the beam of electromagnetic radiation at the first position of the beam of electromagnetic radiation by the first determining unit and determining the characteristic at the second position by the corresponding second determining unit; Each of the corresponding second determination units is calibrated by the control unit taking into account the characteristic of the beam of electromagnetic radiation determined by the first determination unit.

9. A device (1, 101) for manufacturing an object (2) by additive manufacturing, the device (1, 101) comprising: a processing chamber (3) for receiving a molten pool of powdered material (4) capable of being solidified by exposure to electromagnetic radiation; a support (5) for positioning the object (2) relative to a horizontal surface (L) of a molten pool of the powder material (4); a curing device (7) arranged to emit a beam of electromagnetic radiation (9) onto the horizontal surface (L) for curing a selective portion of the powder material (4); a first determining unit (23) arranged and positioned for determining, in use, a characteristic of the beam of electromagnetic radiation (9) at a first position of the beam of electromagnetic radiation (9); a second determination unit (25) arranged and positioned for determining, in use, a characteristic of the beam of electromagnetic radiation (9) at a second position, wherein the second position is displaced relative to the first position, in use, along the beam of electromagnetic radiation (9) towards the curing device (7), or wherein the second position is along another beam of electromagnetic radiation, wherein the another beam of electromagnetic radiation is separated from the beam of electromagnetic radiation (9), the curing device comprising the second determination unit; and A control unit (31) is arranged to calibrate the second determination unit (25) taking into account the characteristic of the beam of electromagnetic radiation (9) determined in use by the first determination unit (23).

10. The device (1, 101) according to claim 9, wherein The first determining unit and / or the second determining unit is arranged to determine at least one of the following: The power, caustics and focus position of the beam of electromagnetic radiation.

11. The device (1, 101) according to claim 9 or 10, wherein: The device comprises a shifting unit arranged to shift the beam of electromagnetic radiation relative to the first determining unit.

12. The device (1, 101) according to claim 9 or 10, wherein The device comprises a measuring chamber accommodating the first determination unit.

13. The device (1, 101) according to claim 12, wherein The measuring chamber is separated from the processing chamber.

14. The device (1, 101) according to claim 9 or 10, wherein The first position is such that a value of the characteristic of the beam of electromagnetic radiation determined by the first determination unit in use of the device is an absolute measure of the characteristic of the beam of electromagnetic radiation at the horizontal surface.

15. The device (1, 101) according to claim 9 or 10, wherein The second position enables determination of the characteristic of the beam of electromagnetic radiation at the second position during the manufacturing of the object.

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