Protective glass cleaning system and protective glass cleaning method

Abstract

The objective is to provide a protective glass cleaning system and protective glass cleaning method that can adequately ensure the quality of molded products. [Solution] The protective glass cleaning system 10A is installed in an additive manufacturing apparatus that irradiates powder with laser light to melt and fuse the powder and create a molded object. It comprises a cleaning mechanism that cleans a protective glass 2 that protects a focusing lens that focuses the laser light from dirt, and a control unit that controls the cleaning mechanism. The control unit controls the cleaning mechanism to clean the protective glass 2 at a predetermined timing during the molding of the molded object.

Description

Technical Field

[0001] The present disclosure relates to a protective glass cleaning system and a protective glass cleaning method.

Background Art

[0002] Conventionally, additive manufacturing technology has been known. Additive Manufacturing (AM) is a process of creating an object from a numerical representation of a three-dimensional shape by depositing materials, which is in contrast to subtractive manufacturing. Additive manufacturing is also called "3D printer" or "layered manufacturing" and is often realized by stacking multiple layers.

[0003] In powder bed additive manufacturing technology, a laser beam or the like is irradiated onto the laid powder to melt and solidify it, and three-dimensional shaping is performed by repeating this process for multiple layers. Here, if a large amount of fumes (metal vapor) generated during shaping adheres to the protective glass of the additive manufacturing apparatus, defects such as poor fusion may occur because the laser beam is absorbed by the fumes or scattered by the fumes. Therefore, it has been necessary to take measures against the adhesion of fumes to the protective glass. As conventional techniques for preventing the adhesion of fumes to the protective glass, for example, Patent Documents 1 and 2 below are known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] One possible method to prevent fume adhesion to protective glass is to reduce fume scattering near the protective glass by circulating and exhausting gas within the build chamber. However, this method cannot completely suppress fume adhesion to the protective glass and carries the risk of degrading build quality. Furthermore, while Patent Document 1 physically removes fumes with a shielding plate during powder laying, fumes generated during build scattering near the protective glass are not effective in preventing fume adhesion to the protective glass. Patent Document 2 describes a method for measuring the degree of fume adhesion to the protective glass and is not effective in preventing fume adhesion to the protective glass.

[0006] Thus, the technologies reported to date have not yet been able to effectively prevent fume adhesion to the protective glass, and have therefore been unable to adequately ensure the quality of the molded products.

[0007] This disclosure is made in view of these circumstances and aims to provide a protective glass cleaning system and protective glass cleaning method that can adequately ensure the quality of molded products. [Means for solving the problem]

[0008] To solve the above problems, the protective glass cleaning system of the present disclosure is provided in an additive manufacturing apparatus that irradiates powder with laser light to melt and bond the powder and create a molded object, and comprises a cleaning mechanism that cleans protective glass that protects a focusing lens that focuses the laser light from dirt, and a control unit that controls the cleaning mechanism, the control unit controlling the cleaning mechanism to clean the protective glass at a predetermined timing during the molding of the molded object.

[0009] The protective glass cleaning method of this disclosure comprises a molding step in which a powder is irradiated with laser light using an additive manufacturing apparatus to melt and bond the powder and form a molded object, and in the molding step, at a predetermined timing during the molding of the molded object, the protective glass that protects the focusing lens that focuses the laser light from dirt is cleaned. [Effects of the Invention]

[0010] The protective glass cleaning system and method disclosed herein perform cleaning of the protective glass during the printing process, rather than at the start or end of the printing process. This prevents large amounts of fumes from adhering to the protective glass during printing, which can lead to defects such as poor fusion. As a result, the cleanliness of the protective glass can be maintained during printing, ensuring sufficient quality of the printed product. [Brief explanation of the drawing]

[0011] [Figure 1] This is a flowchart showing a protective glass cleaning method according to a first embodiment of the present disclosure. [Figure 2] This graph shows the relationship between laser light output and the amount of dirt buildup. [Figure 3] This graph shows the relationship between the amount of focus shift and the amount of dirt accumulation. [Figure 4] This graph shows the relationship between the increase in contamination and "fume mass concentration near the protective glass × molding time". [Figure 5] This figure shows the configuration of the control unit according to the first embodiment of this disclosure. [Figure 6] This is a view of the protective glass cleaning system according to the first embodiment of this disclosure, as seen from the cover side. [Figure 7A] This is a top view showing a schematic configuration of a protective glass cleaning system according to a second embodiment of this disclosure. [Figure 7B] This figure shows the state in which the installation member begins to rotate, starting from the state shown in Figure 7A. [Figure 7C] This figure shows the state after the rotation of the installation member has been completed, compared to the state shown in Figure 7A. [Figure 8A] This is a top view showing a protective glass housing member included in a protective glass cleaning system according to a third embodiment of this disclosure. [Figure 8B] This is a side cross-sectional view showing a protective glass housing member included in a protective glass cleaning system according to a third embodiment of this disclosure. [Figure 9A]It is a top view showing a state where the sliding of the protective glass starts from the state of FIG. 8A. [Figure 9B] It is a side sectional view showing a state where the sliding of the protective glass starts from the state of FIG. 8B. [Figure 10A] It is a top view showing a state where the sliding of the protective glass is completed from the state of FIG. 8A. [Figure 10B] It is a side sectional view showing a state where the sliding of the protective glass is completed from the state of FIG. 8B.

Embodiment for Carrying out the Invention

[0012] Hereinafter, an embodiment of a protective glass cleaning system and a protective glass cleaning method according to the present disclosure will be described with reference to the drawings. The protective glass cleaning system according to the present disclosure can be applied to a known additive manufacturing apparatus that irradiates powder with a laser beam to melt and bond the powder to form a shaped object. Therefore, a detailed description of the overall configuration of the additive manufacturing apparatus will be omitted.

[0013] 〔First Embodiment〕 Hereinafter, the first embodiment of the present disclosure will be described with reference to FIGS. 1 to 6. As shown in FIG. 6, the protective glass cleaning system 10A of the present embodiment includes a circular cover 11 that covers one side of the circular protective glass 2. That is, the outer diameter of the cover 11 is not less than the outer diameter of the protective glass 2. A circular opening 12 is formed in the cover 11. A part of one side of the protective glass 2 is exposed by the opening 12. Note that the shapes of the protective glass 2, the cover 11, and the opening 12 are not limited to circular shapes.

[0014] A rotation axis 13 perpendicular to one surface of the protective glass 2 is connected to the center of the protective glass 2. The protective glass 2 is configured to move (rotate via the rotation axis 13) by a moving mechanism (rotation mechanism) (not shown) such that the position of the opening 12 corresponding to one surface of the protective glass 2 moves relative to it. Note that the moving mechanism is not limited to a rotation mechanism, and may be a moving mechanism that moves linearly. Furthermore, the mechanism may move the cover 11 instead of the protective glass 2, or both.

[0015] Furthermore, the protective glass cleaning system 10A of this embodiment includes a cleaning mechanism (not shown). The cleaning mechanism cleans the protective glass 2 at a predetermined timing during the molding of the object. The cleaning mechanism is controlled by the control unit 50. As the cleaning mechanism, for example, a cleaning mechanism using a brush or a cleaning mechanism that sprays a solvent onto the protective glass can be employed.

[0016] Figure 5 shows the configuration of the control unit 50 according to this embodiment. As shown in Figure 5, the control unit 50 includes a determination unit 51. The control unit 50 is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions are stored in the storage medium in the form of a program, for example. The CPU reads this program into the RAM and performs information processing and calculations to realize the various functions. The program may be pre-installed in the ROM or other storage medium, provided in a state where it is stored in a computer-readable storage medium, or distributed via wired or wireless communication. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memory, etc.

[0017] The determination unit 51 determines a predetermined timing. For example, the determination unit 51 can determine the predetermined timing according to a contamination index of the protective glass 2. Examples of contamination indexes include the amount of contamination increase and the saturation obtained from image recognition of the protective glass. The determination unit 51 can also determine the predetermined timing according to at least one of the following: the material of the powder, the laser irradiation conditions, and the type of additive manufacturing apparatus. Furthermore, the determination unit 51 can determine the predetermined timing based on the product of the mass concentration of fumes scattered near the protective glass 2 and the molding time.

[0018] Here, we will show Figures 2-4 to explain the correlation between the increase in contamination (scattered light intensity) on protective glass 2 and various parameters. Figure 2 is a graph showing the relationship between laser light output and the increase in contamination. Figure 3 is a graph showing the relationship between the amount of focus shift and the increase in contamination. Figure 4 is a graph showing the relationship between the increase in contamination and "fume mass concentration near protective glass × printing time".

[0019] The increase in contamination on protective glass 2 is measured based on the scattered light intensity of the laser light irradiated onto protective glass 2. This measurement can be performed, for example, using a protective glass contamination sensor NMI-300 manufactured by Nishihara Corporation.

[0020] The amount of focus shift is measured by shining laser light onto a profiler, measuring the laser diameter of the laser beam with the profiler, and predicting where the laser is focused. If the protective glass 2 becomes dirty, the focal position will shift due to scattering, etc. The amount of focus shift is measured based on this principle. Note that the amount of focus shift is just one example of a physical quantity measured by the profiler, and the correlation with the dirt index may also be confirmed using other parameters other than the amount of focus shift as physical quantities measured by the profiler.

[0021] The fume mass concentration can be measured using a known method specified in JIS or other standards. Specifically, the fume is physically drawn in using a pump or the like, and the drawn-in fume is collected on a filter (filter paper). After collection, the mass of the fume collected on the filter is measured, and the amount of gas drawn in is also measured. Based on the measured mass of the fume and the amount of gas drawn in, the fume mass concentration can be determined. Regarding the position for drawing in the fume near the protective glass 2, in typical additive manufacturing equipment, an inert gas (such as argon or nitrogen gas) flows inside the chamber. The flow of the fume changes depending on the gas flow inside the chamber. Therefore, a suction port is provided near the protective glass 2 in the direction of the fume flow (a position where the fume can be easily collected relative to the gas flow), and the fume is drawn in.

[0022] As shown in Figure 2, the laser beam output decreases as the amount of dirt on protective glass 2 increases. Furthermore, as shown in Figure 3, the laser beam's focus shifts as the amount of dirt on protective glass 2 increases. These graphs demonstrate that the quality of the laser beam deteriorates in proportion to the increase in dirt on protective glass 2.

[0023] Furthermore, as shown in Figure 4, it has been found that the increase in contamination of protective glass 2 is correlated with the value of "fume mass concentration near protective glass × printing time". Therefore, by confirming the correlation between the value of "fume mass concentration near protective glass × printing time" and how much the quality of the laser beam changes, an appropriate value for "fume mass concentration near protective glass × printing time" can be determined as a criterion. The criterion value is set so that if it is below the criterion, the fumes adhering to protective glass 2 do not significantly affect the printing quality. The fume mass concentration should be measured in a trial run in accordance with the measurement method described above. Based on the determined criterion and the measured fume mass concentration, the printing time (cumulative printing time) at which stable printing is possible can be calculated. The cumulative printing time may be the sum of continuous printing times or intermittent printing times.

[0024] Next, a method for cleaning protective glass using the protective glass cleaning system 10A of this embodiment will be described with reference to the drawings. Here, the explanation will focus on the portion 21 of the protective glass 2 that is located at the first position P1 at a predetermined timing during molding.

[0025] At a predetermined point during the printing process, portion 21 of the protective glass 2 is located at a position corresponding to the opening 12 of the cover 11 (first position P1), and a large amount of fume 101 is adhering to the surface of portion 21 of the protective glass 2. If printing continues in this state, it may affect the quality of the printed object.

[0026] Here, a moving mechanism (rotating mechanism) (not shown) rotates the protective glass 2 around the rotation axis 13. This moves portion 21 of the protective glass 2 sequentially to the second position P2, the third position P3, and the fourth position P4. During movement, the surface of portion 21 of the protective glass 2 is cleaned by the cleaning mechanism, and the fume 101 is removed from the surface. Therefore, as portion 21 of the protective glass 2 moves to the second position P2, the third position P3, and the fourth position P4, the amount of fume 101 adhering to portion 21 of the protective glass 2 is progressively reduced. Meanwhile, the surface of another portion of the protective glass 2, other than portion 21, sequentially moves to the position corresponding to the opening 12 of the cover 11 (first position P1). Therefore, even while portion 21 of the protective glass 2 is being cleaned, molding can continue by irradiating the surface of another portion of the protective glass 2 with laser light. The moving mechanism may be controlled manually or by the control unit 50.

[0027] The surface of the portion 21 of the protective glass 2 that has moved to the fourth position P4 has been thoroughly cleaned during the previous movement and therefore has a sufficient degree of cleanliness. Consequently, even when the portion 21 of the protective glass 2 is moved from the fourth position P4 to the first position P1 and laser light is irradiated, it is possible to suppress the occurrence of defects in the fabricated object due to laser light scattering, etc.

[0028] The timing at which portion 21 of the protective glass 2 moves from the first position P1 to the second position P2, from the second position P2 to the third position P3, from the third position P3 to the fourth position P4, and from the fourth position P4 to the first position P1 can be configured such that each movement occurs at predetermined intervals.

[0029] Next, an example of a protective glass cleaning method by the control unit 50 described above will be explained with reference to Figure 1. Figure 1 is a flowchart of the protective glass cleaning method of this embodiment.

[0030] In step S101, the protective glass cleaning system 10A measures the fume mass concentration near the protective glass 2 in the target material and target device. The specific method for measuring the fume mass concentration is as described above.

[0031] In step S102, the build time required for stable printing is calculated based on the criteria. The method for calculating the build time required for stable printing is as described above.

[0032] In this way, preparations for printing are carried out in steps S101 and S102. Once the preparations for printing are complete, printing is started (step S103).

[0033] Once printing begins, step S104 is performed after each layer is printed to check if the printing time is within the stable printing time limit. If it is within the stable printing time limit (YES in S104), proceed to step S105. If it exceeds the stable printing time limit (NO in S104), proceed to step S106.

[0034] In step S106, the protective glass 2 is cleaned. In this embodiment, the protective glass 2 is cleaned by a cleaning mechanism (not shown). Alternatively, manual cleaning may be performed instead of cleaning by the cleaning mechanism. A possible manual cleaning method is to physically remove the material using a solvent and a cloth. Once the cleaning of the protective glass 2 is complete, proceed to step S105.

[0035] In step S105, it is determined that the next layer can be fabricated, so the fabrication of the next layer proceeds by laying the next layer of powder, etc.

[0036] The above steps S104 to S106 are repeated to proceed with the fabrication of the object. In particular, step S104 is performed after each layer has been fabricated.

[0037] Steps S104 to S106 are repeated until the fabrication of the object is complete, at which point the fabrication process is terminated (step S107). In other words, the period from the start of fabrication of the first layer of the object until the fabrication of all layers is completed corresponds to the "fabrication in progress" stage.

[0038] Once the printing process is complete, clean the protective glass 2 (step S108). After cleaning is complete, proceed to printing the next batch (step S109).

[0039] As described above, this embodiment provides the following effects and advantages. When a laser beam is irradiated onto powder to create a molded part, fumes (metal vapors) 101 are generated. If a large amount of fumes 101 adhere to the protective glass 2, the laser beam may be absorbed by the fumes 101 or scattered by the fumes 101, which can cause defects such as poor fusion. Therefore, in the protective glass cleaning system 10A of this embodiment, the control unit 50 controls the cleaning mechanism to clean the protective glass 2 at a predetermined timing during the molding process. In particular, in this embodiment, the protective glass 2 is cleaned during the molding process, rather than at the start or end of the process. This prevents a large amount of fumes 101 from adhering to the protective glass 2 during the process, which can cause defects such as poor fusion. As a result, the cleanliness of the protective glass 2 during the molding process can be maintained, and the quality of the molded product can be sufficiently ensured.

[0040] If the timing for cleaning the protective glass 2 is determined according to the contamination level of the protective glass 2, cleaning can be performed when the protective glass 2 is contaminated to a degree that affects the laser beam (fumes 101 are attached). Furthermore, it is possible to prevent repeated cleaning of the protective glass 2 when there is not much fume attached. This allows for cleaning of the protective glass 2 at an appropriate and effective time, thereby ensuring better quality of the printed product and improving printing efficiency.

[0041] The amount of fume 101 generated varies depending on the material of the powder used for molding and the laser irradiation conditions. Furthermore, the mass concentration of fume 101 scattered near the protective glass 2 differs depending on the type of additive manufacturing equipment. Therefore, in this embodiment, a trial run is performed before molding the object, and the amount of fume 101 near the protective glass is measured. A predetermined timing is then determined based on at least one of these conditions. Consequently, the timing of cleaning the protective glass 2 can be optimized even if the powder material, laser irradiation conditions, or type of additive manufacturing equipment changes. This ensures more reliable quality of the molded product and further improves molding efficiency.

[0042] The contamination index of the protective glass 2 is correlated with the product of the mass concentration of fumes 101 scattered near the protective glass 2 and the printing time. That is, under conditions below this product, the fumes 101 adhering to the protective glass 2 do not significantly affect the printing quality. Therefore, by determining a predetermined timing using the product of the mass concentration of fumes 101 scattered near the protective glass 2 and the printing time as a criterion, it is possible to calculate a stable printing time (cumulative printing time) according to the powder material, laser irradiation conditions, and type of additive manufacturing equipment. This makes it possible to more reliably ensure the quality of the printed product and to further improve printing efficiency.

[0043] The protective glass cleaning system 10A of this embodiment includes a cover 11 that covers one side (surface) of the protective glass 2, while having an opening 12 that exposes a portion of that side. Therefore, with respect to the protective glass 2, the portion 21 at the position corresponding to the opening 12 of the cover 11 is exposed by the opening 12, and thus fumes 101 adhere to the surface during molding. On the other hand, the portion covered by the cover 11 is not exposed and is therefore protected from the adhesion of fumes 101.

[0044] Furthermore, the protective glass cleaning system 10A of this embodiment is equipped with a moving mechanism that moves the protective glass 2 and / or cover 11 so that the position of the opening 12 corresponding to one side of the protective glass 2 moves relative to it. Therefore, the protective glass 2 and / or cover 11 can be moved when cleaning of the protective glass 2 becomes necessary. This allows the portion of the protective glass 2 covered by the cover 11 to be moved to a position corresponding to the opening 12. In other words, a portion with a large amount of dirt can be quickly switched to a portion with a high degree of cleanliness. Therefore, the molding efficiency can be further improved. At the same time, the portion 21 of the protective glass 2 that is at the position corresponding to the opening 12 of the cover can be moved to a position covered by the cover 11. Since laser light is not irradiated to the position covered by the cover 11, this position is not involved in molding. Therefore, since the portion to which fume 101 has adhered can be cleaned after the move, the cleanliness of the protective glass 2 can be maintained.

[0045] [Second Embodiment] A second embodiment of this disclosure will be described below with reference to Figures 7A and 7B. In this embodiment, only the parts that differ from the first embodiment will be described, and other overlapping parts will not be described. Also, components that are the same as those in the first embodiment will be denoted by the same reference numerals, and their redundant descriptions will be omitted.

[0046] The protective glass cleaning system 10B of this embodiment comprises a plate-shaped installation member 31 and a circular support portion 32 that supports the installation member 31. The installation member 31 has two protective glass installation portions 33 formed therein, each capable of individually installing two protective glass pieces 2. The outer shape of the protective glass 2 is smaller than that of the first embodiment. The shape of each protective glass installation portion 33 is circular, corresponding to the shape of the protective glass 2 to be installed. The shapes of the installation member 31, the support portion 32, and the protective glass installation portions 33 are not limited to these. Furthermore, the number of protective glass installation portions 33 is not limited to two, but may be three or more.

[0047] The protective glass cleaning system 10B includes a cover (not shown) that covers one side of one of the multiple protective glass panes 2 installed in the two protective glass installation sections 33. In this embodiment, the cover (not shown) is provided on the second position P2' side.

[0048] A rotation axis 13 perpendicular to one surface of the installation member 31 is connected to the center of the installation member 31 and the support portion 32. The installation member 31 is configured to move (rotate via the rotation axis 13) by a moving mechanism (rotation mechanism) (not shown) such that the position of the cover corresponding to one surface of the installation member 31 moves relative to it. Note that the moving mechanism is not limited to a rotation mechanism and may be a moving mechanism that moves linearly. Also, the mechanism may move the cover instead of the installation member 31, or both. Furthermore, in this embodiment, a support portion 32 is provided to support the rotation of the installation member 31, but the support portion 32 may not be provided.

[0049] Next, a method for cleaning protective glass using the protective glass cleaning system 10B of this embodiment will be described with reference to the drawings. Here, as an example, we will describe the case in which a large amount of fume 101 adheres to the protective glass 2 located at the first position P1' at a predetermined timing during molding.

[0050] At a predetermined point during the printing process, a large amount of fume 101 adheres to the protective glass 2 located at the first position P1'. If printing continues in this state, it may affect the quality of the printed object.

[0051] Here, a moving mechanism (rotating mechanism), not shown in Figure 7B, rotates the mounting member 31 (and support part 32) around the rotation axis 13. By rotating the mounting member 31, the protective glass 2 that was located in the first position P1' is moved to the second position P2', and the protective glass 2 that was located in the second position P2' is moved to the first position P1', as shown in Figure 7C. In other words, the protective glass 2 that was located in the first position P1' and the protective glass 2 that was located in the second position P2' are swapped. In Figure 7C, a cover is provided on the second position P2' side, so the protective glass 2 at the second position P2' is not exposed. Therefore, by cleaning the protective glass 2 at the second position P2' with the cleaning mechanism, the fume 101 adhering to the protective glass 2 can be removed. On the other hand, as shown in Figure 7A, the protective glass 2 that was located in the second position P2' is clean, so when it is moved to the first position P1' as shown in Figure 7C, it can be immediately irradiated with laser light and used for molding.

[0052] The timing for rotating the installation member 31 by the rotation mechanism may be the predetermined timing determined in the first embodiment. For example, the installation member 31 may be rotated as shown in Figure 7B during the powder laying process between the Nth layer molding (Figure 7A) and the N+1th layer molding (Figure 7C). The moving mechanism may be controlled manually or by the control unit 50.

[0053] As described above, this embodiment provides the following effects and advantages. The protective glass cleaning system 10B of this embodiment includes an installation member 31 having a plurality of protective glass installation sections 33 on which protective glass 2 can be individually installed, and a cover that covers at least one side of the plurality of protective glass 2 installed in the plurality of protective glass installation sections 33. Protective glass 2 in positions not covered by the cover are exposed, and therefore fumes 101 adhere to their surfaces during molding. On the other hand, protective glass 2 covered by the cover are not exposed and are therefore protected from the adhesion of fumes 101.

[0054] Furthermore, in this embodiment, the mounting member 31 and / or cover are provided with a moving mechanism that moves the mounting member 31 and / or cover so that the position of the cover corresponding to one side of the mounting member 31 moves relative to the mounting member 31. Therefore, by moving the mounting member 31 and / or cover when cleaning of the protective glass 2 becomes necessary, the protective glass 2 that is covered by the cover can be moved to a position where it is not covered by the cover. This makes it possible to quickly switch from a protective glass 2 with a large amount of dirt to a protective glass 2 with a high degree of cleanliness. Therefore, the molding efficiency can be further improved. At the same time, the protective glass 2 that is in a position not covered by the cover can be moved to a position covered by the cover. Since the laser light is not irradiated onto the protective glass 2 in a position covered by the cover, this protective glass 2 does not participate in the molding process. Therefore, since the protective glass 2 to which fume 101 has adhered can be cleaned after the move, the cleanliness of the protective glass 2 can be maintained.

[0055] [Third Embodiment] A third embodiment of this disclosure will be described below with reference to Figures 8A to 8B. In this embodiment, only the parts that differ from the first embodiment will be described, and other overlapping parts will not be described. Also, components that are the same as those in the first embodiment will be denoted by the same reference numerals, and their redundant descriptions will be omitted.

[0056] As shown in Figures 8A and 8B, the protective glass cleaning system 10C of this embodiment includes a protective glass housing member 41 having two protective glass housing sections 42 formed inside, each capable of individually housing two protective glass pieces 2. The number of protective glass housing sections 42 is not limited to two; there may be three or more.

[0057] A covering portion 43 is formed on one side of the protective glass housing member 41, covering one side of the protective glass 2 housed in the protective glass housing portion 42. That is, the two protective glass housing portions 42 are provided with a covering position P11 where one side of the protective glass 2 housed in the protective glass housing portion 42 is covered by the covering portion 43.

[0058] On the other side of the protective glass housing member 41, an opening 44 is provided that penetrates from one side to the other side of the protective glass housing member 41, passing through the two protective glass housing sections 42. That is, the two protective glass housing sections 42 are provided with an exposed position P12 that exposes one side of the protective glass 2 housed in the protective glass housing section 42.

[0059] The protective glass cleaning system 10C further includes a sliding mechanism (not shown) that slides the protective glass 2, which is housed in two protective glass housings 42, between a covered position P11 and an exposed position P12.

[0060] Next, a method for cleaning protective glass using the protective glass cleaning system 10C of this embodiment will be described with reference to the drawings. Here, a case will be described as an example in which a large amount of fume (not shown in this embodiment) adheres to the protective glass 2 located at the exposed position P12 at a predetermined timing during molding.

[0061] At a predetermined point during the printing process, a large amount of fume adheres to the protective glass 2 located at the exposed position P12. Continuing the printing process in this state may affect the quality of the printed object.

[0062] Here, a sliding mechanism (not shown) slides the protective glass 2 located at the exposed position P12 (lower part in Figure 9B) and the protective glass 2 located at the covered position P11 (upper part in Figure 9B) to swap places with each other, as shown in Figures 9A and 9B. Once the sliding is complete, as shown in Figures 10A and 10B, the protective glass 2 that was at the exposed position P12 (lower part in Figure 8B) moves to the covered position P11, and the protective glass 2 that was at the covered position P11 (upper part in Figure 8B) moves to the exposed position P12. The protective glass 2 that has moved to the covered position P11 (lower part in Figure 10B) is not exposed because a covering portion 43 has been formed on it. Therefore, by cleaning the protective glass 2 at the covered position P11 with the cleaning mechanism, the fumes adhering to the protective glass 2 can be removed. On the other hand, since the protective glass 2 that was at the covered position P11 is clean, it can be immediately irradiated with laser light and used for molding when it is moved to the exposed position P12 as shown in Figures 10A and 10B.

[0063] The timing for sliding the protective glass 2 by the sliding mechanism may be the predetermined timing determined in the first embodiment. For example, the protective glass 2 may be slid as shown in Figures 9A and 9B during powder laying between the Nth layer molding (Figures 8A and 8B) and the N+1th layer molding (Figures 10A and 10B). The sliding mechanism may be controlled manually or by the control unit 50.

[0064] As described above, this embodiment provides the following effects and advantages. The protective glass cleaning system 10C of this embodiment includes a protective glass housing member 41 having a plurality of protective glass housing sections 42 formed thereon, each capable of individually housing protective glass 2; a covering position P11 provided in the plurality of protective glass housing sections 42, where one side of the protective glass 2 housed in the plurality of protective glass housing sections 42 is covered with a covering section 43; and an exposure position P12 provided in the plurality of protective glass housing sections 42, where one side of the protective glass 2 housed in the plurality of protective glass housing sections 42 is exposed. Since the surface of the protective glass 2 at the exposure position P12 is exposed, fumes adhere to the surface during molding. On the other hand, since the surface of the protective glass 2 at the covering position P11 is not exposed, it is protected from the adhesion of fumes during molding.

[0065] Furthermore, this embodiment includes a sliding mechanism that slides the protective glass 2 housed in multiple protective glass housings 42 between a covered position P11 and an exposed position P12. Therefore, when cleaning of the protective glass 2 becomes necessary, the protective glass 2 located at the covered position P11 and the protective glass 2 located at the exposed position P12 can be slid and swapped using the sliding mechanism. This allows the protective glass 2 located at the covered position P11 to be moved to the exposed position P12. This enables quick replacement of a heavily soiled protective glass 2 with a cleaner protective glass 2. Consequently, the molding efficiency can be further improved. At the same time, the protective glass 2 that was at the exposed position P12 can be moved to the covered position P11. Since the protective glass 2 at the covered position P11 is not irradiated with laser light, this protective glass 2 does not participate in the molding process. Therefore, the protective glass 2 with fume attached can be cleaned after the move, thus maintaining the cleanliness of the protective glass 2. In addition, this method is more space-efficient than using a separate moving mechanism.

[0066] <Note> The protective glass cleaning system and protective glass cleaning method described in the embodiments above can be understood, for example, as follows.

[0067] A protective glass cleaning system (1A) according to a first aspect of the present disclosure is provided in an additive manufacturing apparatus that irradiates powder with laser light to melt and fuse the powder to form a molded object, and comprises a cleaning mechanism for cleaning a protective glass (2) that protects a focusing lens for focusing the laser light from dirt, and a control unit (50) that controls the cleaning mechanism, the control unit controlling the cleaning mechanism to clean the protective glass at a predetermined timing during the formation of the molded object.

[0068] When a laser beam is irradiated onto powder to create a molded part, fumes (metal vapors) (101) are generated. If a large amount of fumes adhere to the protective glass, the laser beam may be absorbed by the fumes or scattered by the fumes, which can cause defects such as poor fusion. Therefore, in the protective glass cleaning system of this disclosure, the control unit controls the cleaning mechanism to clean the protective glass at a predetermined timing during the molding process. In particular, in this disclosure, the protective glass is cleaned during the molding process, rather than at the start or end of the process. This prevents a large amount of fumes from adhering to the protective glass during the process, which can cause defects such as poor fusion. As a result, the cleanliness of the protective glass during the molding process can be maintained, and the quality of the molded product can be sufficiently ensured.

[0069] A protective glass cleaning system according to a second aspect of the present disclosure further comprises, in the first aspect, a determination unit (51) for determining the predetermined timing, the determination unit for determining the predetermined timing according to the dirt index of the protective glass.

[0070] If the timing of cleaning the protective glass is determined according to the degree of contamination on the protective glass, cleaning can be performed when the protective glass is contaminated (fumes have accumulated) to a degree that affects the laser beam. Furthermore, it can prevent repeated cleaning of the protective glass when there is little or no fume accumulation. This allows for cleaning of the protective glass at the appropriate and effective timing, thereby ensuring better quality of the printed product and improving printing efficiency.

[0071] A protective glass cleaning system according to a third aspect of the present disclosure further comprises, in the first or second aspect, a determination unit for determining the predetermined timing, the determination unit for determining the predetermined timing according to at least one of the material of the powder, the irradiation conditions of the laser light, and the type of additive manufacturing apparatus.

[0072] The amount of fume generated varies depending on the material of the powder used in the molding process and the laser irradiation conditions. Furthermore, the mass concentration of fumes scattered near the protective glass differs depending on the type of additive manufacturing equipment. Therefore, in this disclosure, a trial run is performed before molding the object, and the amount of fume near the protective glass is measured. A predetermined timing is then determined based on at least one of these conditions. Consequently, the timing of cleaning the protective glass can be optimized even if the powder material, laser irradiation conditions, or type of additive manufacturing equipment changes. This ensures more reliable quality of the molded product and further improves molding efficiency.

[0073] A protective glass cleaning system according to a fourth aspect of the present disclosure further comprises a determination unit for determining the predetermined timing in any of the first to third aspects, the determination unit for determining the predetermined timing based on the product of the mass concentration of fumes scattered near the protective glass and the molding time.

[0074] The contamination index of the protective glass is correlated with the product of the mass concentration of fumes scattered near the protective glass and the printing time. In other words, under conditions below this product, the fumes adhering to the protective glass do not significantly affect the printing quality. Therefore, by determining a predetermined timing using the product of the mass concentration of fumes scattered near the protective glass and the printing time as a criterion, it is possible to calculate a stable printing time (cumulative printing time) according to the powder material, laser irradiation conditions, and type of additive manufacturing equipment. This makes it possible to more reliably ensure the quality of the printed product and to further improve printing efficiency.

[0075] A protective glass cleaning system according to a fifth aspect of the present disclosure, in any of the first to fourth aspects, comprises a cover (11) that covers one side of the protective glass and has an opening (12) that exposes a part of the one side of the protective glass, and a moving mechanism that moves the protective glass and / or the cover such that the position of the opening corresponding to one side of the protective glass moves relative to each other.

[0076] The protective glass cleaning system of this disclosure includes a cover that covers one side (surface) of the protective glass, while having an opening that exposes a portion of that side. Therefore, the portion of the protective glass corresponding to the opening in the cover is exposed by the opening, and thus fumes adhere to the surface during molding. On the other hand, the portion covered by the cover is not exposed and is therefore protected from fume adhesion.

[0077] Furthermore, the protective glass cleaning system of this disclosure includes a moving mechanism that moves the protective glass and / or cover such that the position of the opening corresponding to one side of the protective glass moves relative to it. Therefore, the protective glass and / or cover can be moved when cleaning of the protective glass becomes necessary. This allows the portion of the protective glass covered by the cover to be moved to the position corresponding to the opening. In other words, areas with a large amount of dirt can be quickly switched to areas with a high degree of cleanliness. Therefore, the molding efficiency can be further improved. At the same time, the portion of the protective glass that is located at the position corresponding to the opening of the cover can be moved to the position covered by the cover. Since laser light is not irradiated to the position covered by the cover, this position does not participate in the molding process. Therefore, since the portion to which fumes have adhered after the move can be cleaned, the cleanliness of the protective glass can be maintained.

[0078] One example of a moving mechanism is a rotation mechanism that rotates the protective glass around a rotation axis (13) perpendicular to one surface of the protective glass.

[0079] A protective glass cleaning system (1B) according to a sixth aspect of the present disclosure, in any of the first to fourth aspects, comprises: an installation member (31) having a plurality of protective glass installation sections (33) formed thereon, on which a plurality of protective glass can be individually installed; a cover that covers at least one side of the plurality of protective glass installed in the plurality of protective glass installation sections; and a moving mechanism that moves the installation member and / or the cover such that the position of the cover corresponding to one side of the installation member moves relative to it.

[0080] The protective glass cleaning system of this disclosure comprises an installation member having a plurality of protective glass installation sections formed thereon, on which protective glass can be individually installed, and a cover that covers at least one side of the plurality of protective glass installed in the plurality of protective glass installation sections. Protective glass in positions not covered by the cover is exposed, and therefore fumes adhere to its surface during molding. On the other hand, protective glass covered by the cover is not exposed and is therefore protected from fume adhesion.

[0081] Furthermore, this disclosure includes a moving mechanism that moves the mounting member and / or cover such that the position of the cover corresponding to one side of the mounting member moves relative to the mounting member. Therefore, by moving the mounting member and / or cover when cleaning of the protective glass becomes necessary, the protective glass covered by the cover can be moved to a position where it is not covered by the cover. This allows for a quick switch from heavily soiled protective glass to a more clean protective glass. Consequently, the molding efficiency can be further improved. At the same time, protective glass that is not covered by the cover can be moved to a position where it is covered by the cover. Since laser light is not irradiated onto protective glass in the covered position, this protective glass does not participate in the molding process. Therefore, the protective glass to which fumes have adhered can be cleaned after the move, thus maintaining the cleanliness of the protective glass.

[0082] One example of a moving mechanism is a rotation mechanism that rotates the mounting member around a rotation axis perpendicular to one of its surfaces.

[0083] A protective glass cleaning system (1C) according to a seventh aspect of the present disclosure comprises, in any of the first to fourth aspects, a protective glass housing member (41) having a plurality of protective glass housing sections (42) formed thereon capable of individually housing a plurality of protective glass pieces; a covering position (P11) provided in the plurality of protective glass housing sections, covering one side of the protective glass housed in the plurality of protective glass housing sections with a covering section (43); an exposure position (P12) provided in the plurality of protective glass housing sections, exposing one side of the protective glass housed in the plurality of protective glass housing sections; and a sliding mechanism for sliding the protective glass housed in the plurality of protective glass housing sections between the covering position and the exposure position.

[0084] The protective glass cleaning system of this disclosure comprises a protective glass housing member having a plurality of protective glass housing sections capable of individually housing protective glass, a covering position provided in the plurality of protective glass housing sections and covering one side of the protective glass housed in the plurality of protective glass housing sections with a covering section, and an exposure position provided in the plurality of protective glass housing sections and exposing one side of the protective glass housed in the plurality of protective glass housing sections. Since the surface of the protective glass in the exposure position is exposed, fumes adhere to the surface during molding. On the other hand, since the surface of the protective glass in the covering position is not exposed, it is protected from the adhesion of fumes during molding.

[0085] Furthermore, this disclosure includes a sliding mechanism that slides protective glass housed in multiple protective glass housings between a covered position and an exposed position. Therefore, when cleaning of the protective glass becomes necessary, the protective glass in the covered position and the protective glass in the exposed position can be slid and swapped using the sliding mechanism. This allows the protective glass in the covered position to be moved to the exposed position. This allows for quick replacement of heavily soiled protective glass with a more clean protective glass. Therefore, the manufacturing efficiency can be further improved. At the same time, the protective glass that was in the exposed position can be moved to the covered position. Since the protective glass in the covered position is not irradiated with laser light, this protective glass does not participate in the manufacturing process. Therefore, the protective glass that has accumulated fumes after being moved can be cleaned, thus maintaining the cleanliness of the protective glass. In addition, this method is more space-efficient than using a separate moving mechanism.

[0086] A protective glass cleaning method according to the eighth aspect of this disclosure comprises a molding step in which a powder is irradiated with laser light by an additive manufacturing apparatus to melt and bond the powder and form a molded object, wherein in the molding step, at a predetermined timing during the molding of the molded object, the protective glass that protects the focusing lens that focuses the laser light from dirt is cleaned.

[0087] When a laser beam is irradiated onto powder to create a molded part, fumes (metal vapors) are generated. If a large amount of fumes adhere to the protective glass, the laser beam may be absorbed by or scattered by the fumes, potentially causing defects such as poor fusion. Therefore, in this disclosure, the protective glass is cleaned at a predetermined timing during the molding process. In particular, in this disclosure, the protective glass is cleaned during the molding process, rather than at the start or end of the process. This prevents a large amount of fumes from adhering to the protective glass during the process, which can cause defects such as poor fusion. As a result, the cleanliness of the protective glass during the molding process can be maintained, and the quality of the molded product can be sufficiently ensured. [Explanation of symbols]

[0088] 2. Protective glass 10A, 10B, 10C Protective Glass Cleaning System 11 Cover 12 Openings 13 Rotation axis 21. Protective glass portion 31 Installation components 32 Support part 33 Protective glass installation area 41 Protective glass housing member 42 Protective glass housing 43 Covering part 44 openings 50 Control Unit 51 Decision Section 101 Hume P1,P1' 1st position P2,P2' 2nd position P3 3rd position P4 4th position P11 Covering position P12 Exposure position

Claims

1. An additive manufacturing apparatus that irradiates powder with laser light to melt and fuse the powder and create a molded object is provided with a cleaning mechanism for cleaning a protective glass that protects the focusing lens that focuses the laser light from dirt, A control unit that controls the cleaning mechanism, Equipped with, The control unit controls the cleaning mechanism to clean the protective glass at a predetermined timing during the molding of the molded object, and this is a protective glass cleaning system.

2. The system further comprises a determination unit for determining the predetermined timing, The protective glass cleaning system according to claim 1, wherein the determination unit determines the predetermined timing according to the dirt index of the protective glass.

3. The system further comprises a determination unit for determining the predetermined timing, The protective glass cleaning system according to claim 1, wherein the determination unit determines the predetermined timing according to at least one of the material of the powder, the irradiation conditions of the laser light, and the type of additive manufacturing apparatus.

4. The system further comprises a determination unit for determining the predetermined timing, The protective glass cleaning system according to claim 1, wherein the determination unit determines the predetermined timing based on the product of the mass concentration of fumes scattered near the protective glass and the molding time.

5. A cover that covers one side of the protective glass and has an opening that exposes a part of that side of the protective glass, A moving mechanism for moving the protective glass and / or the cover such that the position of the opening corresponding to one surface of the protective glass moves relative to it, A protective glass cleaning system according to any one of claims 1 to 4, comprising:

6. An installation member having multiple protective glass installation sections formed thereon, which allow multiple protective glass panels to be individually installed, A cover that covers at least one side of the plurality of protective glass pieces installed in the plurality of protective glass installation sections, A moving mechanism for moving the mounting member and / or the cover such that the position of the cover corresponding to one side of the mounting member moves relative to it, A protective glass cleaning system according to any one of claims 1 to 4, comprising:

7. A protective glass housing member having multiple protective glass housing sections formed therein, each capable of individually housing multiple protective glass panels, A covering position provided in the plurality of protective glass housings, which covers one side of the protective glass housed in the plurality of protective glass housings with a covering portion, An exposure position provided in the plurality of protective glass housings, which exposes one side of the protective glass housed in the plurality of protective glass housings, A sliding mechanism for sliding the protective glass housed in the plurality of protective glass housings between the covering position and the exposed position, A protective glass cleaning system according to any one of claims 1 to 4, comprising:

8. The additive manufacturing apparatus has a molding process in which a laser beam is irradiated onto powder to melt and fuse the powder together and create a molded object. A method for cleaning protective glass, which involves cleaning a protective glass that protects the focusing lens for focusing laser light from dirt at a predetermined timing during the molding process of the molded object.

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