Additive Manufacturing of Microstructures

Abstract

The present invention relates to a method for additively manufacturing microstructures for the selective transmission of X-ray or gamma-ray radiation. The method includes depositing a layer of powder on a build plate or on a layer from at least one previous manufacturing step on a build plate, wherein the powder layer comprises a powder of a high-Z material. The method further includes selectively melting and solidifying the powder by scanning an electron beam in a spot array over the powder layer so that the electron beam spots sequentially strike multiple spots on the powder layer to form a barrier structure. The electron beam spot size is up to 150 μm in diameter, preferably up to 75 μm in diameter, and more preferably up to 50 μm in diameter. The powder of high-Z material comprises a high-Z material with an atomic number Z of at least 40, and preferably at least 70. The present invention also relates to a microstructure for the selective transmission of X-ray or gamma-ray radiation obtained by the method, and to an imaging component having such a microstructure. The present invention also relates to a method for manufacturing an imaging component.

Description

[Technical Field]

[0001] The present invention relates to a method for additive manufacturing, more particularly to a method for additively manufacturing microstructures for the selective transmission of X-ray or gamma-ray radiation. The invention also relates to microstructures obtained by said method for the selective transmission of X-ray or gamma-ray radiation, and to imaging components having such microstructures. The invention also relates to a method for manufacturing an imaging component. [Background technology]

[0002] For example, additive manufacturing techniques such as direct metal laser sintering (DMLS) or laser powder bed fusion (LPBF) show great promise for the fabrication of microstructures selective for X-ray and gamma-ray transmission, such as anti-scatter devices, 2D anti-scatter grids, etc. In some cases, other manufacturing techniques may be required, for example, for microstructures with higher density, higher purity, and / or fewer microcracks.

[0003] US 2021 / 0039322 A1 describes a method for providing a control command set for an additive manufacturing device, the method comprising the steps of: providing a parameter set consisting of a plurality of parameters and drawing rules suitable for geometrically depicting at least one portion of an object according to said parameter set as a plurality of linear or flat elements in space, generating, for each layer, a computer-based layer model of the portion of this object by determining the position and cross-sectional shape of the portion of the object within this layer, and generating, based on the layer model, a control command set for an additive manufacturing device by which the manufacturing of the portion of the object is performed.

[0004] WO 2022 / 248519 A1 provides a method and apparatus for making an anti-scatter grid recognizable for a radiological imaging device, the method comprising the steps of forming, by an additive manufacturing process, a grid pattern in accordance with product specifications for the anti-scatter grid to be provided, and forming, by the additive manufacturing process, a number of structural modifications in or within the grid pattern in a manner that makes the structural modifications image-based recognizable when the anti-scatter grid is viewed in accordance with its intended use in a viewing direction from a radiation source of the radiological imaging device.

[0005] Electron beam powder bed fusion (E-PBF) uses an electron beam to selectively melt metal powder into a solid material in a vacuum chamber. E-PBF reduces residual material stresses and reduces cracking due to the high build temperatures. E-PBF is commonly used to build microstructures in materials such as titanium-aluminum alloys, cobalt-chromium alloys, or nickel-based alloys.

[0006] Research Disclosure #697065 suggests the feasibility of using E-PBF to additively manufacture metal parts with refractory metals such as tungsten and its alloys.

[0007] US 2015 / 0017013 A1 discloses a method for manufacturing a turbomachine impeller including a hub and a plurality of blades using powder material in an additive manufacturing process. The method includes applying energy to the powder material using a high-energy source and solidifying the powder material. At least one thick portion of the hub is irradiated, and the powder material solidifies into a lattice structure surrounded by a solid skin structure that encases the lattice structure.

[0008] The June 5, 2016 publication "State of the arts of additive manufacturing by selective electron beam melting" by Mladenov Georgi et al. reviews the applications of electron beam additive manufacturing systems. Summary of the Invention [Problem to be solved by the invention]

[0009] The E-PBF techniques known in the literature are not suitable for the production of X-ray and gamma-ray transmission-selective microstructures, such as anti-scatter grids, since this type of transmission-selective microstructure has the advantage of high surface quality, high resolution, high septum density, etc. Therefore, there is a need to improve the production of these microstructures. [Means for solving the problem]

[0010] It is an object of the present invention to provide improved fabrication of microstructures for the selective transmission of X-ray or gamma-ray radiation.

[0011] The invention is defined by the independent claims. Advantageous embodiments are defined in the dependent claims.

[0012] According to a first aspect of the present invention, there is provided a method for additively manufacturing microstructures for the selective transmission of X-ray or gamma-ray radiation, the method comprising: depositing a layer of powder onto a build plate or onto a layer from at least one previous manufacturing step on the build plate, the layer of powder comprising powder of a high-Z material; selectively melting and solidifying the powder by scanning an electron beam in a spot array over the layer of powder so that the electron beam spot sequentially strikes a plurality of spots on the layer of powder to form a barrier structure, the size of the electron beam spot being at most 150 μm in diameter, preferably at most 75 μm in diameter, and more preferably at most 50 μm in diameter; It has.

[0013] The proposed manufacturing method enables high productivity of microstructures with high-density barriers for selective transmission of X-ray or gamma-ray radiation. These structures can be constructed without support structures and have excellent surface properties with little or no microcracks compared to previously known manufacturing techniques. It is generally known that high electron beam densities for powder bed spot melting can cause melting problems, such as charging and smoking events. However, the inventors surprisingly discovered that, when combined with high-Z material powders, it is advantageous to use very small electron beam spot sizes, and therefore, for a given electron beam power, very high beam energy densities for spot melting of barrier structures. The combination of the very high material density of the high-Z material and the small electron beam spot size allows the method to produce microstructures with high resolution. This allows the method to achieve desired local to global functional properties of microstructures for selective transmission of X-ray or gamma radiation, such as anti-scatter grids. The current of the electron beam may be, for example, 10-100 mA and the scanning speed may be, for example, up to 2 m / s or higher.

[0014] A high-Z material is a material (element) with a high atomic number Z. The high-Z material is preferably a metal. The high-Z material may preferably be tungsten (Wolfram, atomic number 74). Other high-Z materials, such as, but not limited to, molybdenum (Mo, atomic number 42), tantalum (Ta, atomic number 73), niobium (Nb, atomic number 41), lead (Pb, atomic number 82), bismuth (Bi, atomic number 83), rhenium (Re, atomic number 75), silver (Ag, atomic number 47), or gold (Au, atomic number 79), may alternatively, additionally, or in combination be used. Thus, in the context of the present disclosure, a high-Z material has an atomic number Z of at least 40, preferably at least 70. The powder of high-Z material may alternatively, additionally, or in combination comprise an alloy containing at least one high-Z material.

[0015] According to one embodiment of the present invention, the powder of high-Z material has a particle size distribution with a median diameter of at most 50 μm, preferably at most 25 μm, most preferably at most 20 μm. It has been found that optimal results are obtained with powders having a narrow particle size distribution, despite the very high energy density of the beam.

[0016] According to an embodiment of the present invention, the deposited powder layer has a layer thickness of 10 μm to 50 μm, i.e., the 10 μm to 50 μm boundary is included in the claimed scope. For example, the thin layer of powder combined with the small particle size and narrow electron beam allows for the production of high-density partition walls with high resolution.

[0017] According to one embodiment of the present invention, the method further comprises selectively preheating powder spots by scanning the electron beam over the layer of powder in a spot pre-sintering array, where the spot pre-sintering array is performed before the spot array. Preheating or pre-sintering the powder spots with the electron beam can improve subsequent melting of the powder in the spot array.

[0018] According to one embodiment of the present invention, the scanning direction and the spot arrangement of the pre-sintering array are the same as the scanning direction and the spot arrangement of the spot arrangement for all spots, or the scanning direction and the spot arrangement of the pre-sintering array are the same as the scanning direction and the spot arrangement of the spot arrangement for a plurality of spots. Pre-heating and melting the powder according to the same or partially the same pattern is advantageous for forming high-density partition walls.

[0019] According to one embodiment of the present invention, the microstructured partition structure comprises first wall structures each having a respective length axis parallel to a first direction and second wall structures each having a respective length axis parallel to a second direction, wherein the second direction is at an angle to the first direction. When the partitions are in two different directions, such as, but not limited to, at angles of 90 degrees, 60 degrees, or 45 degrees, it is possible to advantageously fabricate grid microstructures, such as, for example, radiation anti-scatter grids.

[0020] According to one embodiment of the present invention, a spot array for sequentially applying an electron beam spot to a plurality of spots on a powder layer includes a first array followed by a second array, wherein the first array includes scanning the electron beam spot to sequentially apply the electron beam spot to a plurality of spots on the length axis parallel to a first direction, and the second array includes scanning the electron beam spot to sequentially apply the electron beam spot to a plurality of spots on the length axis parallel to a second direction.

[0021] This specialized spot melting strategy, relative to the length axis of the formed septum, reduces the amount of powder sintered within a pixel of the grid, allowing for high resolution. Furthermore, this strategy can be used to achieve a desired grain structure for each septum.

[0022] According to one embodiment of the present invention, the first array includes scanning an electron beam spot along a path of a plurality of first partitions whose respective length axes are parallel to a first direction, and the second array includes scanning an electron beam spot along a path of a plurality of second partitions whose respective length axes are parallel to a second direction. By first scanning the electron beam spot along the path of the partitions corresponding to the first direction and then scanning it along the path of the partitions corresponding to the second direction, it is possible to advantageously manufacture partitions in each direction. In this context, scanning along the path of the partitions means that the electron beam spot sequentially hits adjacent spots on the path, and thus the electron beam spot moves along this path. It should be noted that the movement of the spot along the path of the first partitions can be either parallel or anti-parallel to the first direction. Similarly, the movement of the spot along the path of the second partitions can be either parallel or anti-parallel to the second direction.

[0023] According to one embodiment of the present invention, the partition structure has a wall thickness of at most 200 μm, preferably at most 100 μm, more preferably at most 70 μm.

[0024] According to one embodiment of the present invention, the septum structure has a height-to-thickness aspect ratio of at least 100, preferably at least 200, and more preferably at least 400. Fabricating a microstructure of thin septum walls, such as, but not limited to, septum walls having a thickness of up to 100 μm, and particularly septum walls having a very large height-to-thickness ratio, such as, but not limited to, thin septum walls having a height of at least 40 mm, allows for precise control of the transmission of X-ray or gamma-ray radiation, including, but not limited to, a microstructure that efficiently reduces radiation scattering while keeping radiation intensity loss due to the wall thickness low.

[0025] According to a second aspect of the present invention there is provided a microstructure for the selective transmission of X-ray or gamma-ray radiation, which is obtained by a method according to the first aspect or any embodiment thereof.

[0026] According to a third aspect of the present invention there is provided an imaging component having the microstructure described above.

[0027] According to one embodiment of the present invention, the imaging component comprises a plurality of stacked microstructures. Stacking multiple microstructures to form the imaging component is advantageous for improving ease of manufacturing.

[0028] According to one embodiment of the present invention, the imaging component comprises: X-ray or gamma ray filters, X-ray or gamma-ray collimators, X-ray or gamma ray scatter removal equipment, and X-ray or gamma-ray diffraction grating The present invention has one or more of the following:

[0029] According to a fourth aspect of the present invention, there is provided a method of manufacturing an imaging component, the method comprising manufacturing at least one microstructure according to the first aspect or any embodiment of the first aspect, and forming an imaging component from the at least one microstructure. Forming the imaging component from the at least one microstructure can include steps such as adjusting a form factor, adding connections, adding layers or other components, modifying a surface, or incorporating the microstructure into a holder or frame or similar structure. The manufactured imaging component is suitable for use in an imaging system.

[0030] According to one embodiment of the present invention, fabricating the imaging component comprises stacking a plurality of microstructures. Stacking a plurality of microstructures to form the imaging component is advantageous for improving ease of manufacturing.

[0031] According to one embodiment of the present invention, the imaging component comprises: X-ray or gamma ray filters, X-ray or gamma-ray collimators, X-ray or gamma ray scatter removal equipment, and X-ray or gamma-ray diffraction grating The present invention has one or more of the following:

[0032] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 illustrates a schematic of a method for additively manufacturing microstructures for the selective transmission of X-ray or gamma-ray radiation, according to one embodiment of the present invention. [Figure 2] FIG. 2 illustrates a schematic of a method for additively manufacturing microstructures for selective transmission of X-ray or gamma-ray radiation, including selective pre-heating, according to one embodiment of the present invention. [Figure 3a] FIG. 3a shows a schematic representation of a microstructure for the selective transmission of X-ray or gamma-ray radiation, according to one embodiment of the present invention. [Figure 3b] FIG. 3b shows a schematic representation of a microstructure for selective transmission of X-ray or gamma-ray radiation, according to one embodiment of the present invention. [Figure 4a] FIG. 4a shows a schematic diagram of a spot array for additively manufacturing microstructures for the selective transmission of X-ray or gamma-ray radiation, according to one embodiment of the present invention. [Figure 4b] FIG. 4b shows a schematic diagram of a spot array for additively manufacturing microstructures for the selective transmission of X-ray or gamma-ray radiation, according to one embodiment of the present invention. [Figure 5] FIG. 5 shows an optical surface image of a partition wall made by an additive manufacturing method, according to one embodiment of the present invention. [Figure 6] FIG. 6 shows an image of an individual septum made by an additive manufacturing method, according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 1 illustrates, in a flowchart, a method for additively manufacturing a microstructure 10 for selective transmission of X-ray or gamma-ray radiation according to an embodiment of the present invention. The method of FIG. 1 includes depositing a layer of powder (110) on a build plate or on at least one layer from a previous manufacturing step on the build plate, where the layer of powder comprises a powder of a high-Z material. The high-Z material may include, for example, tungsten, molybdenum, tantalum, niobium, lead, bismuth, rhenium, silver, or gold. Combinations of high-Z materials and / or alloys containing at least one high-Z material may also be used. By way of non-limiting example, high-purity high-Z material powders can be used in conjunction with the method. In this way, it is possible to achieve very high-purity diaphragms. It is particularly advantageous to use high-Z material powders with a purity of more than 99% (by weight of the high-Z material), preferably more than 99.9%. Such powders include, for example, high-purity tungsten powders with a purity of more than 99%, preferably more than 99.9%. The powder of high-Z material may have a particle size distribution with a median diameter of up to 50 μm, preferably up to 25 μm, and most preferably up to 20 μm. It has been found that optimal results are obtained with powders having a narrow particle size distribution, despite the very high energy density of the beam, for example, but not limited to, electron beams with beam currents of up to 100 mA or greater. The deposited layer of powder can advantageously have a layer thickness of 10 μm to 50 μm.

[0035] In the next step 120 of the method shown in FIG. 1, the layer of powder is selectively melted and solidified to form the barrier structure 20. This is achieved by scanning an electron beam over the layer of powder in a spot array, sequentially striking multiple spots 40 on the layer of powder, such as those shown in FIG. 4a. For best results, the electron beam spot size can be preferably up to 150 μm in diameter, more preferably up to 75 μm in diameter, and even more preferably up to 50 μm in diameter. The method can enable high productivity of microstructures 10 with dense barrier ribs 20 for selective transmission of X-ray or gamma-ray radiation. The structures can be constructed without support structures and have excellent surface properties with little or no microcrack formation compared to previously known manufacturing techniques. Due to the very high material density (high-Z material), combined with the small electron beam spot size, the method allows for high-resolution fabrication of microstructures. The thin layer of powder, combined with, for example, small grain size, also allows for high-resolution fabrication of dense barrier ribs 20.

[0036] FIG. 2 illustrates a method similar to that of FIG. 1, with the additional step 210 of selectively preheating powder spots in the spot array before selectively melting and solidifying the powder (120). In this example, powder spots 40 are selectively preheated (210) by scanning an electron beam over the powder layer in a spot preheating array. Thus, the spot preheating array is performed before the spot array. Selectively and precisely preheating or presintering powder spots 40 using the electron beam can improve subsequent melting of the powder by the spot array. The scanning direction and spot arrangement of the presintering array can be the same for all spots 40 or for multiple spots 40 as the scanning direction and spot arrangement of the spot array.

[0037] 3a and 3b schematically illustrate a microstructure 10 fabricated by a method according to an embodiment of the present invention. The microstructure 10 allows selective transmission of X-ray or gamma-ray radiation and can therefore be advantageously used in imaging components such as, for example, X-ray or gamma-ray filters, X-ray or gamma-ray collimators, X-ray or gamma-ray anti-scatter devices, and / or X-ray or gamma-ray diffraction gratings. The microstructure 10 has a partition structure 20 in one or more directions. In the example of FIGS. 3a and 3b, the microstructure 10 is a grid-like structure having partitions 20 in a first direction d1 and a second direction d2. Such a structure can be used, for example, for a two-dimensional anti-scatter grid. In the example of FIGS. 3a and 3b, the angle between the partitions 20 in the first direction d1 and the partitions 20 in the second direction d2 is approximately 90 degrees. However, other structures having different angles between the partitions are also contemplated, such as, but not limited to, honeycomb-like structures. Figure 3a shows a side view of an exemplary microstructure 10. In this case, the partitions 20 seen from the side view of Figure 3a have a length in a first direction d1 and a height h. Figure 3b illustrates the same microstructure 10 seen from above. As can be seen, the microstructure 10 has partitions 20 in the direction d1 and, in this case, perpendicular direction d2.

[0038] The partition walls have a thickness w. In FIG. 3b, all the partition walls have the same thickness w, but various partition walls may have different thicknesses. The partition walls 20 are dense structures that can efficiently absorb or reflect radiation. The spaces between the partition walls form transparent portions 30 that allow radiation to pass through. Using a manufacturing method according to an embodiment of the present invention, dense and thin partition walls 20 can be manufactured. The partition walls can have a wall thickness w of up to 200 μm, preferably up to 100 μm, or more preferably up to 70 μm. Each partition wall 20 has a height h and a thickness w. The partition walls 20 may have an aspect ratio of the height h to the thickness w of at least 100, preferably at least 200, and more preferably at least 400. For example, partition walls 20 for anti-scatter grids advantageously have a thickness w of 70 to 100 μm and a height h of 40 to 50 mm. Such microstructures 10, with their large ratio of height h to thickness w, allow for precise control of the transmission of X-ray or gamma-ray radiation through the transparent portion 30, while minimizing the loss of radiation intensity due to the thickness w of the wall 20. To manufacture imaging components comprising such microstructures 10, multiple microstructures 10 can be stacked and / or tiled on top of each other to achieve the desired specifications of the component, such as overall height, area, etc.

[0039] 4a and 4b schematically illustrate spot arrays for additively manufacturing microstructures for selective transmission of X-ray or gamma-ray radiation, according to one embodiment of the present invention. In each spot array, multiple spots 40 on a layer of powder of high-Z material are sequentially struck with an electron beam to melt and solidify the powder during the process of forming a barrier structure 20. FIG. 4a illustrates a spot array in direction d1, and FIG. 4b illustrates a spot array in direction d2. The exemplary microstructure 10 of FIGS. 4a and 4b has three barrier ribs 20 parallel to direction d1 and three barrier ribs parallel to direction d2. In this particular example, d1 is orthogonal to d2, although angles other than 90° between these directions are possible depending on the specifications of the microstructure 10 at hand. The total spot array for melting and solidifying (fully or partially) the powder to build each layer of the 3×3 barrier ribs 20 in FIGS. 4a and 4b may include three arrays parallel to the direction d1 and three arrays parallel to the direction d2. For example, the array starts with three paths along the three barrier ribs 20 in the direction d1, such as from A to B, C to D, and E to F in FIG. 4a, followed by three series of paths parallel to the direction d2, such as from G to H, I to J, and K to L in FIG. 4b. For each path, the electron beam sequentially strikes multiple spots 40. The electron beam current is, for example, 10 to 100 mA, and the scanning speed is, for example, up to 2 m / s or more. This spot array strategy allows achieving the desired grain structure (equiaxed / columnar structure) of the manufactured barrier ribs 20. In addition, the amount of sintered powder in the transparent portions (pixels) 30 of the microstructure 10 can be reduced.

[0040] Other spot arrangement options are possible. For example, in FIG. 4a, the individual paths may be arranged from right to left or left to right. Similarly, in FIG. 4b, the individual paths may be arranged from top to bottom or bottom to top. For illustrative purposes, non-limiting examples of arrangements in direction d1 are A to B, D to C and E to F, or F to E, C to D and B to A, or E to F, C to D and A to B, etc. Similarly, different top-to-bottom or bottom-to-top variations of the paths in FIG. 4b are also possible. This specialized spot melting strategy can reduce the amount of sintered powder within a pixel of the grid, enabling high resolution. Furthermore, this strategy can be used to achieve a desired grain structure in each of the partition walls 20.

[0041] 4a and 4b may be alternated, with one sequence in the d1 direction followed by one sequence in the d2 direction, such as, but not limited to, A to B followed by G to H, C to D followed by I to J, and E to F followed by K to L. Again, many variations in the direction and / or order of the sequences are possible.

[0042] 4a and 4b are merely schematic representations. Any sequence in the d1 or d2 direction may be shorter or longer than illustrated in the figures. By way of non-limiting example, the sequence in the d1 or d2 direction may be shortened and / or skip spots 40, e.g., to avoid repeated melting at spots 40 melted in the respective d2 or d1 direction.

[0043] For example, in one example of a method including the additional step 210 of selectively preheating powder spots 40 before the powder is selectively melted and solidified (120) in a spot array, it is advantageous for the scanning direction and spot arrangement of the pre-sintering array to be the same or similar to the scanning direction and spot arrangement of the spot array. That is, with reference to the example of FIGS. 4a and 4b, the selective pre-heating of powder spots 40 follows the same scanning sequence as described above. This may be true for all spots 40, or the scanning direction and spot arrangement of the pre-sintering array may be the same or similar to the scanning direction and spot arrangement of a spot array of multiple spots 40. Pre-heating and melting powder according to the same or partially the same pattern is advantageous for forming high-density partition walls 20. To achieve high-density partition walls 20, such fabrication is particularly advantageous for the fabrication of microstructures 10 for selectively transmitting X-ray or gamma-ray radiation, such as those included in a 2D anti-scatter grid.

[0044] Figure 5 shows an optical surface image of a partition wall made by an additive manufacturing method according to one embodiment of the present invention. The left and right sides of the image show the same portion of the surface under different lighting conditions in an optical microscope. The image clearly shows the pattern of individually applied spots 40 as part of a spot melting strategy.

[0045] 6 shows an image of an individual partition wall produced by an additive manufacturing method according to one embodiment of the present invention, where multiple walls are produced in a first direction, e.g., d1.

[0046] It should be noted that the above-described embodiments illustrate the present invention rather than limit it, and that those skilled in the art can design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The absence of a plurality of elements does not exclude the presence of a plurality of such elements. "Maximum" means "less than or equal to," and "at least" means "equal to or greater than." The present invention may be implemented by means of hardware comprising several distinct elements, and / or by means of a suitably programmed processor. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. Measures recited in mutually different dependent claims may be advantageously combined.

Claims

1. 1. A method for additively manufacturing microstructures for selective transmission of x-ray or gamma-ray radiation, said method comprising: depositing a layer of powder onto a build plate or onto a layer from at least one previous manufacturing step on the build plate, the layer of powder comprising a powder of a high-Z material, the powder of the high-Z material comprising a high-Z material having an atomic number Z of at least 40, and preferably at least 70; selectively melting and solidifying the powder by scanning an electron beam in a spot array over the layer of powder so as to sequentially apply a plurality of electron beam spots to the layer of powder to form a barrier structure, wherein the size of the electron beam spots is up to 150 μm in diameter, preferably up to 75 μm in diameter, and more preferably up to 50 μm in diameter; A method comprising:

2. 2. The method of claim 1, wherein the powder of high-Z material comprises tungsten, and / or molybdenum, and / or tantalum, and / or niobium, and / or lead, and / or bismuth, and / or rhenium, and / or silver, and / or gold.

3. 3. The method according to claim 1 or 2, wherein the powder of high-Z material has a particle size distribution with a median diameter of at most 50 μm, preferably at most 25 μm, most preferably at most 20 μm.

4. The method according to claim 1, 2 or 3, wherein the layer of powder deposited has a layer thickness between 10 μm and 50 μm.

5. 5. The method of claim 1, further comprising the step of selectively pre-heating the powder spots by scanning the electron beam over the layer of powder in a spot pre-sintering array, the spot pre-sintering array being performed before the spot arranging.

6. 6. The method of claim 5, wherein the scanning direction and spot arrangement of the pre-sintering array are the same as the scanning direction and spot arrangement of the spot array for all spots, or the scanning direction and spot arrangement of the pre-sintering array are the same as the scanning direction and spot arrangement of the spot array for multiple spots.

7. 7. The method of claim 1, wherein the microstructured partition structures comprise first wall structures each formed with a respective length axis parallel to a first direction and second wall structures each formed with a respective length axis parallel to a second direction, the second direction being at an angle to the first direction.

8. 8. The method of claim 7, wherein the spot array for sequentially applying the electron beam spot to a plurality of spots on the powder layer comprises a first array followed by a second array, the first array comprising scanning the electron beam spot to sequentially apply the electron beam spot to a plurality of spots on the length axis parallel to the first direction, and the second array comprising scanning the electron beam spot to sequentially apply the electron beam spot to a plurality of spots on the length axis parallel to the second direction.

9. 9. The method of claim 8, wherein the first array comprises scanning the electron beam along paths of a plurality of first partitions on respective length axes parallel to the first direction, and the second array comprises scanning the electron beam along paths of a plurality of second partitions on respective length axes parallel to the second direction.

10. 10. The method according to any one of the preceding claims, wherein the partition structure has a wall thickness of at most 200 μm, preferably at most 100 μm, more preferably at most 70 μm.

11. 11. The method of any one of claims 1 to 10, wherein the partition structure has an aspect ratio of thickness to height of at least 100, preferably at least 200, more preferably at least 400.

12. A microstructure for the selective transmission of X-ray or gamma-ray radiation obtained by a method according to any one of claims 1 to 11.

13. An imaging component having the microstructure of claim 12.

14. The imaging component of claim 13 , wherein the imaging component comprises a plurality of stacked microstructures.

15. The imaging component comprises: X-ray or gamma ray filters, X-ray or gamma-ray collimators, X-ray or gamma ray scatter removal equipment, and X-ray or gamma-ray diffraction grating 15. The imaging component of claim 13 or 14, comprising one or more of:

16. Manufacturing at least one microstructure according to the method of any one of claims 1 to 11; forming an imaging component from the at least one microstructure; and A method of manufacturing an imaging component having:

17. The method of claim 16 , wherein forming the imaging component comprises stacking a plurality of the microstructures.

18. The imaging component comprises: X-ray or gamma ray filters, X-ray or gamma-ray collimators, X-ray or gamma ray scatter removal equipment, and X-ray or gamma-ray diffraction grating 18. The method of claim 16 or 17, comprising one or more of:

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