Protective glass cleaning system and protective glass cleaning method

Abstract

The purpose of the present invention is to provide a protective glass cleaning system and a protective glass cleaning method with which it is possible to sufficiently ensure the quality of a fabricated article. A protective glass cleaning system (10A) is provided to an additive manufacturing device for fabricating a fabricated object by irradiating a powder with laser light to melt and bond the powder. The protective glass cleaning system (10A) comprises: a cleaning mechanism that cleans protective glass (2) for protecting a condensing lens which condenses the laser light from fouling; and a control unit that controls the cleaning mechanism. The control unit controls the cleaning mechanism so as to clean the protective glass (2) at a prescribed timing during fabrication of a fabricated object.

Description

Protective glass cleaning system and protective glass cleaning method

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

[0002] Additive manufacturing techniques have been known for some time. Additive manufacturing (AM) is a process in which an object is created from a numerical representation of a three-dimensional shape by depositing material, as opposed to subtractive manufacturing. Additive manufacturing, also known as "3D printing" or "additive manufacturing," is often achieved by building up multiple layers.

[0003] In powder bed additive manufacturing, a laid powder is irradiated with a laser beam or the like to melt and solidify it, and this process is repeated multiple times to form a three-dimensional shape. Here, if a large amount of fumes (metal vapor) generated during the manufacturing process adheres to the protective glass of the additive manufacturing device, the laser light can be absorbed or scattered by the fumes, resulting in defects such as incomplete fusion. Therefore, it has been necessary to take measures to prevent fume adhesion to the protective glass. Conventional techniques for preventing fume adhesion to protective glass are known, for example, from Patent Documents 1 and 2 listed below.

[0004] International Publication No. WO 2018 / 225334 International Publication No. WO 2023 / 063063

[0005] One method for preventing fume adhesion to the protective glass is to flow gas into the manufacturing chamber and exhaust it to reduce fume scattering near the protective glass. However, it is not possible to completely prevent fume adhesion to the protective glass, which could lead to a decrease in manufacturing quality. Furthermore, in Patent Document 1, fumes are physically removed using a shielding plate when laying powder, but fumes generated during manufacturing scatter near the protective glass, so this is not effective in preventing fume adhesion to the protective glass. Furthermore, Patent Document 2 is a method for measuring the degree of fumes adhering to the protective glass, which is not effective in preventing fume adhesion to the protective glass.

[0006] As described above, the techniques reported so far have not yet been able to effectively prevent fume adhesion to the protective glass, and have had the problem of not being able to fully ensure the quality of the molded product.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a protective glass cleaning system and a protective glass cleaning method that can sufficiently ensure the quality of the molded product.

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

[0009] The protective glass cleaning method disclosed herein includes a manufacturing process in which an additive manufacturing device irradiates a powder with laser light to melt and bond the powder to form a molded object, and during the manufacturing process, cleaning is performed on the protective glass that protects the focusing lens that focuses the laser light from dirt at a predetermined timing during the manufacturing of the molded object.

[0010] In the protective glass cleaning system and protective glass cleaning method disclosed herein, the protective glass is cleaned during the printing process, not at the start or end of printing, and this prevents a large amount of fumes from adhering to the protective glass during printing, which can cause defects such as poor fusion. This allows the cleanliness of the protective glass to be maintained during printing, and the quality of the printed product to be sufficiently ensured.

[0011] 7A . FIG. 7B is a flowchart showing a protective glass cleaning method according to a first embodiment of the present disclosure. FIG. 7C is a graph showing the relationship between laser light output and the amount of dirt increase. FIG. 7D is a graph showing the relationship between the amount of focus shift and the amount of dirt increase. FIG. 7E is a graph showing the relationship between the amount of dirt increase and "fume mass concentration near the protective glass × modeling time". FIG. 7F is a diagram showing the configuration of a control unit according to a first embodiment of the present disclosure. FIG. 7G is a diagram showing the protective glass cleaning system according to the first embodiment of the present disclosure as viewed from the cover side. FIG. 7H is a top view showing a schematic configuration of a protective glass cleaning system according to a second embodiment of the present disclosure. FIG. 7G is a diagram showing a state in which rotation of the installation member is started from the state of FIG. 7A . FIG. 7H is a diagram showing a state in which rotation of the installation member is completed from the state of FIG. 7A . FIG. 7H is a top view showing a protective glass container member included in a protective glass cleaning system according to a third embodiment of the present disclosure. FIG. 7I is a side cross-sectional view showing a protective glass container member included in a protective glass cleaning system according to a third embodiment of the present disclosure. FIG. 7I is a top view showing a state in which sliding of the protective glass is started from the state of FIG. 8A . FIG. 7I is a side cross-sectional view showing a state in which sliding of the protective glass is started from the state of FIG. 8B . FIG. 7I is a top view showing a state in which sliding of the protective glass is completed from the state of FIG. 8A . FIG. 7I is a side cross-sectional view showing a state in which sliding of the protective glass is completed from the state of FIG. 8B .

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

[0013] First Embodiment A first embodiment of the present disclosure will now be described with reference to Figures 1 to 6. As shown in Figure 6, a protective glass cleaning system 10A of this embodiment includes a circular cover 11 that covers one side of a circular protective glass 2. That is, the outer diameter of the cover 11 is equal to or greater than the outer diameter of the protective glass 2. A circular opening 12 is formed in the cover 11. The opening 12 exposes a portion of one side of the protective glass 2. Note that the shapes of the protective glass 2, the cover 11, and the opening 12 are not limited to circular.

[0014] A rotation shaft 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 shaft 13) by a movement mechanism (rotation mechanism) not shown so that the position of the opening 12 corresponding to one surface of the protective glass 2 moves relatively. Note that the movement mechanism is not limited to a rotation mechanism, and may be a movement mechanism that moves linearly. Furthermore, a mechanism may be used that moves the cover 11 instead of the protective glass 2, or a mechanism that moves both.

[0015] The protective glass cleaning system 10A of this embodiment also includes a cleaning mechanism (not shown). The cleaning mechanism cleans the protective glass 2 at a predetermined timing during the formation 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 adopted.

[0016] FIG. 5 is a diagram showing the configuration of a control unit 50 according to this embodiment. As shown in FIG. 5, the control unit 50 includes a determination unit 51. The control unit 50 is configured, for example, with a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program, for example. The CPU reads the program into the RAM or the like and executes information processing and arithmetic operations to realize various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0017] The determination unit 51 determines the predetermined timing. As an example, the determination unit 51 can determine the predetermined timing according to a dirt index of the protective glass 2. Examples of the dirt index include the amount of dirt increase and saturation obtained from image recognition of the protective glass. Furthermore, the determination unit 51 can determine 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 device. 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 modeling time.

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

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

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

[0021] Fume mass concentration can be measured using known methods specified in JIS and other standards. Specifically, fumes are physically sucked in using a pump or other device and then collected on a filter (filter paper). After collection, the mass of the fumes collected on the filter is measured, and the amount of gas sucked in is also measured. The fume mass concentration can be calculated based on the measured mass of the fumes and the amount of gas sucked in. Regarding the position where fumes are sucked in near the protective glass 2, in a typical additive manufacturing device, an inert gas (argon gas, nitrogen gas, etc.) is flowed inside the chamber. The flow of fumes changes depending on the gas flow inside the chamber. Therefore, an intake port is provided near the protective glass 2 along the direction of fume flow (a position where fumes can be easily collected relative to the gas flow), and fumes are sucked in.

[0022] As shown in Figure 2, it can be seen that the output of the laser light decreases as the amount of dirt on the protective glass 2 increases. Also, as shown in Figure 3, it can be seen that the focus of the laser light shifts as the amount of dirt on the protective glass 2 increases. These graphs show that the quality of the laser light decreases in accordance with the increase in dirt on the protective glass 2.

[0023] Furthermore, as shown in FIG. 4 , it has been found that the increase in contamination on the protective glass 2 is also correlated with the value of “fume mass concentration near the protective glass × printing time.” Therefore, by confirming the correlation between the change in laser light quality caused by the value of “fume mass concentration near the protective glass × printing time,” it is possible to determine an appropriate value of “fume mass concentration near the protective glass × printing time” as a criterion. The criterion value is a value below which fumes adhering to the protective glass 2 do not significantly affect printing quality. The fume mass concentration is measured in advance during a trial run using the above-mentioned measurement method. Based on the determined criteria and the measured fume mass concentration, the printing time (cumulative printing time) during which stable printing is possible can be calculated. The cumulative printing time may be the sum of continuous printing time or intermittent printing time.

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

[0025] At a predetermined timing during the modeling, the portion 21 of the protective glass 2 is present at a position (first position P1) corresponding to the opening 12 of the cover 11, and a large amount of fumes 101 adheres to the surface of the portion 21 of the protective glass 2. If the modeling continues in this state, there is a possibility that the quality of the modeled object will be affected.

[0026] Here, a moving mechanism (rotating mechanism) (not shown) rotates the protective glass 2 around the rotation axis 13. This causes the portion 21 of the protective glass 2 to move sequentially from the second position P2 to the third position P3 and the fourth position P4. During this movement, the surface of the portion 21 of the protective glass 2 is cleaned by the cleaning mechanism, and fumes 101 are removed from the surface. Therefore, as the portion 21 of the protective glass 2 moves sequentially from the second position P2 to the third position P3 and the fourth position P4, the amount of fumes 101 adhering to the portion 21 of the protective glass 2 gradually decreases. Meanwhile, other portions of the surface of the protective glass 2 other than the portion 21 of the protective glass 2 sequentially move to the position (first position P1) corresponding to the opening 12 of the cover 11. Therefore, even while the portion 21 of the protective glass 2 is being cleaned, shaping can continue by irradiating the surface of other portions of the protective glass 2 other than the portion 21 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 portion 21 of protective glass 2 that has moved to fourth position P4 has been sufficiently cleaned during the movement up to that point, and is therefore sufficiently clean. Therefore, even if portion 21 of protective glass 2 is moved from fourth position P4 to first position P1 and irradiated with laser light, it is possible to prevent defects from occurring in the shaped object due to scattering of the laser light, etc.

[0028] The timing at which the 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 may be configured so that each of these movements occurs at a predetermined timing, for example.

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

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

[0031] In step S102, the modeling time during which stable modeling is possible is calculated based on the criteria. The method for calculating the modeling time during which stable modeling is possible is as described above.

[0032] In this way, the preparations before modeling are performed in Steps S101 and S102. Then, when the preparations before modeling are completed, modeling starts (Step S103).

[0033] Once modeling begins, step S104 is performed after each layer is modeled to check whether the modeling time is within the stable modeling time. If the stable modeling time is within the stable modeling time (YES in S104), the process proceeds to step S105. If the stable modeling time is exceeded (NO in S104), the process proceeds 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). Note that instead of cleaning by the cleaning mechanism, manual cleaning may be performed. A conceivable manual cleaning method is to physically remove the residue using a solvent and a rag. Once cleaning of the protective glass 2 is complete, the process proceeds to step S105.

[0035] In step S105, since it is determined that the next modeling is possible, modeling of the next layer is proceeded by, for example, laying down the next layer of powder.

[0036] The above steps S104 to S106 are repeated to form the object. In particular, step S104 is performed after each layer is formed.

[0037] Steps S104 to S106 are repeated until the formation of the object is completed, at which point the formation ends (step S107). In other words, the period from when the formation of the first layer of the object starts until the formation of all layers is completed corresponds to "during formation."

[0038] After the molding is completed, the protective glass 2 is cleaned (step S108). After the cleaning is completed, the molding of the next batch is started (step S109).

[0039] The above-described configuration of this embodiment provides the following advantageous effects. When a laser beam is irradiated onto a powder to form a molded portion, fumes (metal vapor) 101 are generated. If a large amount of fumes 101 adheres to the protective glass 2, the laser beam may be absorbed or scattered by the fumes 101, resulting in 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 of the molded object. In particular, in this embodiment, the cleaning of the protective glass 2 is performed during the molding, rather than at the start or end of the molding. This prevents a large amount of fumes 101 from adhering to the protective glass 2 during the molding, which can result in defects such as poor fusion caused by the adhered fumes 101. This allows the cleanliness of the protective glass 2 to be maintained during the molding, thereby ensuring the quality of the molded object.

[0040] If the timing for cleaning the protective glass 2 is determined in accordance with the contamination index of the protective glass 2, the protective glass 2 can be cleaned at a timing when the protective glass 2 is contaminated to an extent that it affects the laser light (when fumes 101 are attached). Furthermore, it is possible to prevent the protective glass 2 from being cleaned multiple times in a situation where not many fumes are attached to the protective glass 2. This allows the protective glass 2 to be cleaned at an appropriate and effective timing, which can more sufficiently ensure the quality of the molded product and further improve the molding efficiency.

[0041] The amount of fumes 101 generated varies depending on the material of the powder used in the manufacturing process and the laser light irradiation conditions. Furthermore, the mass concentration of the fumes 101 scattered near the protective glass 2 varies depending on the type of additive manufacturing device. Therefore, in this embodiment, a trial run is performed before the manufacturing of a molded object, the fumes 101 near the protective glass are measured, and the predetermined timing is determined based on at least one of these conditions. Therefore, even if the material of the powder, the laser light irradiation conditions, or the type of additive manufacturing device changes, the timing for cleaning the protective glass 2 can be optimized. This makes it possible to more reliably ensure the quality of the molded product and further improve the manufacturing efficiency.

[0042] The contamination index of the protective glass 2 is correlated with the product of the mass concentration of fumes 101 scattered in the vicinity of the protective glass 2 and the manufacturing time. In other words, if the condition is below this product, the fumes 101 adhering to the protective glass 2 do not significantly affect the manufacturing quality. Therefore, if the predetermined timing is determined using the product of the mass concentration of fumes 101 scattered in the vicinity of the protective glass 2 and the manufacturing time as a criterion, it is possible to calculate the manufacturing time (cumulative manufacturing time) that allows stable manufacturing depending on the powder material, the laser light irradiation conditions, and the type of additive manufacturing device. This makes it possible to more reliably ensure the quality of the manufactured product and further improve the manufacturing efficiency.

[0043] The protective glass cleaning system 10A of this embodiment includes a cover 11 that covers one side (front side) of the protective glass 2 and has an opening 12 formed therein that exposes a portion of the one side of the protective glass 2. Therefore, a portion 21 of the protective glass 2 that corresponds to the opening 12 of the cover 11 is exposed by the opening 12, and fumes 101 adhere to the surface during modeling. On the other hand, a portion that is 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 movement mechanism that moves the protective glass 2 and / or the cover 11 so that the position of the opening 12 corresponding to one side of the protective glass 2 moves relative to the protective glass 2. Therefore, the protective glass 2 and / or the 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 heavily soiled portion can be quickly switched to a portion with high cleanliness. This further improves the shaping efficiency. At the same time, the portion 21 of the protective glass 2 corresponding to the opening 12 of the cover can be moved to a position covered by the cover 11. Because the laser light is not irradiated onto the portion covered by the cover 11, this position does not participate in shaping. Therefore, the portion with fumes 101 attached can be cleaned after the movement, thereby maintaining the cleanliness of the protective glass 2.

[0045] Second Embodiment A second embodiment of the present disclosure will be described below with reference to Figures 7A and 7B. In this embodiment, only the differences from the first embodiment will be described, and descriptions of other overlapping parts will be omitted. In addition, the same components as those in the first embodiment will be assigned the same reference numerals, and overlapping descriptions will be omitted.

[0046] The protective glass cleaning system 10B of this embodiment includes a plate-shaped installation member 31 and a circular support portion 32 that supports the installation member 31. The installation member 31 is formed with two protective glass installation portions 33 that can install two protective glasses 2 individually. The outer shape of the protective glasses 2 is smaller than in the first embodiment. The shape of each protective glass installation portion 33 is circular to correspond 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. The number of protective glass installation portions 33 is also not limited to two, and 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 glasses 2 installed in the two protective glass installation units 33. In this embodiment, a cover (not shown) is provided on the second position P2′ side.

[0048] A rotation shaft 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 shaft 13) by a movement mechanism (rotation mechanism) (not shown) so that the position of the cover corresponding to one surface of the installation member 31 moves relatively. Note that the movement mechanism is not limited to a rotation mechanism, and may be a movement mechanism that moves linearly. Also, a mechanism may be used that moves the cover instead of the installation member 31, or a mechanism that moves both. Furthermore, in this embodiment, the 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 protective glass cleaning method using the protective glass cleaning system 10B of this embodiment will be described with reference to the drawings. Here, a case where a large amount of fumes 101 adheres to the protective glass 2 located at the first position P1′ at a predetermined timing during modeling will be described as an example.

[0050] At a predetermined timing during modeling, a large amount of fumes 101 adheres to the protective glass 2 located at the first position P1′. If modeling continues in this state, there is a possibility that the quality of the modeled object will be affected.

[0051] Here, as shown in FIG. 7B , a moving mechanism (rotating mechanism) (not shown) rotates the installation member 31 (and the support portion 32) around the rotation axis 13. By continuing the rotation of the installation member 31, as shown in FIG. 7C , the protective glass 2 located at the first position P1′ is moved to the second position P2′, and the protective glass 2 located at the second position P2′ is moved to the first position P1′. That is, the protective glass 2 located at the first position P1′ and the protective glass 2 located at the second position P2′ are swapped. In FIG. 7C , a cover is provided on the second position P2′ side, so the protective glass 2 located at the second position P2′ is not exposed. Therefore, by cleaning the protective glass 2 located at the second position P2′ with a cleaning mechanism, the fumes 101 adhering to the protective glass 2 can be removed. On the other hand, since the protective glass 2 located at the second position P2′ is clean as shown in FIG. 7A , it can be immediately irradiated with laser light and used for modeling when it is moved to the first position P1′ as shown in FIG. 7C .

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

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

[0054] Furthermore, this embodiment includes a moving mechanism that moves the installation member 31 and / or the cover so that the position of the cover corresponding to one side of the installation member 31 moves relative to the installation member 31. Therefore, by moving the installation member 31 and / or the cover when cleaning of the protective glass 2 becomes necessary, the covered protective glass 2 can be moved to a position where it is not covered. This allows a highly soiled protective glass 2 to be quickly replaced with a highly clean protective glass 2. This further improves the shaping efficiency. At the same time, the protective glass 2 located in a position where it is not covered can be moved to a position where it is covered. Since the laser light is not irradiated onto the protective glass 2 located in a position where it is covered, this protective glass 2 does not participate in shaping. Therefore, the protective glass 2 with fumes 101 attached thereto can be cleaned after movement, thereby maintaining the cleanliness of the protective glass 2.

[0055] 8A to 10B, a third embodiment of the present disclosure will be described. In this embodiment, only the differences from the first embodiment will be described, and descriptions of other overlapping parts will be omitted. Furthermore, the same components as those in the first embodiment will be assigned the same reference numerals, and overlapping descriptions will be omitted.

[0056] 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 therein that can individually house two protective glasses 2. The number of protective glass housing sections 42 is not limited to two, and may be three or more.

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

[0058] An opening 44 is provided on the other side of the protective glass housing member 41, penetrating from one side to the other side of the protective glass housing member 41 so as to pass through the two protective glass housing sections 42. That is, each of the two protective glass housing sections 42 is provided with an exposure 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 slide mechanism (not shown) that slides the protective glass 2 housed in the two protective glass housing portions 42 between the covered position P11 and the exposed position P12.

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

[0061] At a predetermined timing during modeling, a large amount of fumes adheres to the protective glass 2 located at the exposed position P12. If modeling continues in this state, there is a possibility that the quality of the modeled object will be affected.

[0062] Here, as shown in FIGS. 9A and 9B , a sliding mechanism (not shown) slides the protective glass 2 (lower row in FIG. 9B ) located at the exposed position P12 and the protective glass 2 (upper row in FIG. 9B ) located at the covered position P11, respectively, to replace each other. When the sliding is complete, as shown in FIGS. 10A and 10B , the protective glass 2 (lower row in FIG. 8B ) located at the exposed position P12 moves to the covered position P11, and the protective glass 2 (upper row in FIG. 8B ) located at the covered position P11 moves to the exposed position P12. The protective glass 2 (lower row in FIG. 10B ) moved to the covered position P11 is not exposed because the covering portion 43 is formed on it. Therefore, by cleaning the protective glass 2 at the covered position P11 with a cleaning mechanism, fumes adhering to the protective glass 2 can be removed. Meanwhile, the protective glass 2 located at the covered position P11 is clean, so when it is moved to the exposed position P12 as shown in FIGS. 10A and 10B , it can be immediately irradiated with laser light and used for modeling.

[0063] The timing at which the protective glass 2 is slid 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 being built (Figures 8A and 8B) and the N+1th layer being built (Figures 10A and 10B). The sliding mechanism may be controlled manually or by the control unit 50.

[0064] The above-described configuration of this embodiment provides the following advantageous effects. The protective glass cleaning system 10C of this embodiment includes a protective glass housing member 41 having multiple protective glass housing sections 42 each capable of housing a protective glass 2 individually, covering positions P11 provided in the multiple protective glass housing sections 42 and covering one side of the protective glass 2 housed in the multiple protective glass housing sections 42 with a covering section 43, and exposure positions P12 provided in the multiple protective glass housing sections 42 and exposing one side of the protective glass 2 housed in the multiple protective glass housing sections 42. The protective glass 2 present at the exposure position P12 has an exposed surface, allowing fumes to adhere to the surface during printing. On the other hand, the protective glass 2 present at the covering position P11 has an unexposed surface, allowing fumes to adhere to the surface during printing.

[0065] Furthermore, this embodiment includes a slide mechanism that slides the protective glass 2 accommodated in the multiple protective glass accommodation sections 42 between the covering position P11 and the exposed position P12. Therefore, when cleaning of the protective glass 2 is required, the slide mechanism can slide the protective glass 2 at the covering position P11 and the protective glass 2 at the exposed position P12 to interchange them. This allows the protective glass 2 at the covering position P11 to be moved to the exposed position P12. This allows the protective glass 2 with a high level of contamination to be quickly replaced with a protective glass 2 with a high level of cleanliness. This further improves shaping efficiency. At the same time, the protective glass 2 at the exposed position P12 can be moved to the covering position P11. Because the protective glass 2 at the covering position P11 is not irradiated with laser light, this protective glass 2 does not participate in shaping. Therefore, the protective glass 2 with fumes attached can be cleaned after movement, thereby maintaining the cleanliness of the protective glass 2. This method is also more space-efficient than using a moving mechanism.

[0066] <Additional Notes> The protective glass cleaning system and protective glass cleaning method described in the above-described embodiments 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 device that irradiates a powder with laser light to melt and bond the powder to form a molded object, and includes 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 (50) that controls the cleaning mechanism, and the control unit controls 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 a powder to form a molded part, fumes (metal vapor) (101) are generated. If a large amount of fumes adhere to the protective glass, the laser beam may be absorbed or scattered by the fumes, resulting in defects such as poor fusion. Therefore, in the protective glass cleaning system disclosed herein, the control unit controls the cleaning mechanism to clean the protective glass at a predetermined timing during the molding of the molded object. In particular, in the present disclosure, the protective glass is cleaned during the molding process, rather than at the start or end of the molding process. This prevents a large amount of fumes from adhering to the protective glass during the molding process, which can cause defects such as poor fusion. This allows the cleanliness of the protective glass to be maintained during the molding process, ensuring sufficient quality of the molded product.

[0069] The protective glass cleaning system according to the second aspect of the present disclosure is, in the first aspect, further provided with a determination unit (51) that determines the specified timing, and the determination unit determines the specified timing according to a dirt index of the protective glass.

[0070] If the timing for cleaning the protective glass is determined based on the contamination index of the protective glass, the protective glass can be cleaned at a timing when the protective glass is contaminated (has fumes attached) to an extent that it affects the laser light. Furthermore, it is possible to prevent the protective glass from being cleaned multiple times when there is not much fumes attached to the protective glass. This allows the protective glass to be cleaned at an appropriate and effective timing, thereby more fully ensuring the quality of the molded product and further improving the molding efficiency.

[0071] The protective glass cleaning system according to the third aspect of the present disclosure, in the first or second aspect, further includes a determination unit that determines the predetermined timing, and 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 the additive manufacturing device.

[0072] The amount of fumes generated varies depending on the material of the powder used for modeling and the laser light irradiation conditions. Furthermore, the mass concentration of fumes dispersed near the protective glass varies depending on the type of additive manufacturing device. Therefore, in the present disclosure, a trial run is performed before modeling an object, and fumes near the protective glass are measured. The predetermined timing is determined based on at least one of these conditions. Therefore, even if the powder material, laser light irradiation conditions, or type of additive manufacturing device change, the timing for cleaning the protective glass can be optimized. This makes it possible to more reliably ensure the quality of the modeled product and further improve modeling efficiency.

[0073] The protective glass cleaning system according to the fourth aspect of the present disclosure, in any one of the first to third aspects, further includes a determination unit that determines the specified timing, and the determination unit determines the specified timing based on the product of the mass concentration of fumes scattered in the vicinity of the protective glass and the printing time.

[0074] The contamination index of the protective glass correlates with the product of the mass concentration of fumes dispersed near the protective glass and the printing time. In other words, if the product is below this value, fumes adhering to the protective glass do not significantly affect the printing quality. Therefore, by determining the predetermined timing using the product of the mass concentration of fumes dispersed near the protective glass and the printing time as a criterion, it is possible to calculate the printing time (cumulative printing time) that allows stable printing depending on the powder material, laser light irradiation conditions, and type of additive manufacturing device. This makes it possible to more reliably ensure the quality of the molded product and further improve printing efficiency.

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

[0076] The protective glass cleaning system of the present disclosure includes a cover that covers one side (front side) of the protective glass and has an opening that exposes a portion of the one side of the protective glass. Therefore, the portion of the protective glass that corresponds to the opening in the cover is exposed by the opening, and fumes adhere to the surface during modeling. On the other hand, the portion covered by the cover is not exposed, and is therefore protected from fumes.

[0077] Furthermore, the protective glass cleaning system disclosed herein includes a movement mechanism that moves the protective glass and / or the cover so that the position of the opening corresponding to one side of the protective glass moves relative to the protective glass. Therefore, the protective glass and / or the 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 a position corresponding to the opening. That is, a portion with a high level of contamination can be quickly switched to a portion with a high level of cleanliness. Therefore, the shaping efficiency can be further improved. At the same time, the portion of the protective glass that corresponds to the opening of the cover can be moved to a position covered by the cover. Because the laser light is not irradiated onto the portion covered by the cover, this position does not participate in shaping. Therefore, the portion with fumes attached can be cleaned after the movement, thereby maintaining the cleanliness of the protective glass.

[0078] An example of the movement 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) on which a plurality of the protective glasses can be installed individually, a cover that covers one side of at least one of the plurality of protective glasses installed in the plurality of protective glass installation sections, and a moving mechanism that moves the installation member and / or the cover so that the position of the cover corresponding to one side of the installation member moves relatively.

[0080] The protective glass cleaning system of the present disclosure includes a mounting member having a plurality of protective glass mounting sections on which protective glass can be individually mounted, and a cover that covers one side of at least one of the plurality of protective glass pieces mounted on the plurality of protective glass mounting sections. Protective glass pieces that are not covered by the cover are exposed, and therefore fumes adhere to their surfaces during modeling. On the other hand, protective glass pieces that are covered by the cover are not exposed, and therefore are protected from fumes.

[0081] The present disclosure also includes a moving mechanism that moves the installation member and / or cover so that the position of the cover corresponding to one surface of the installation member moves relative to the installation member. Therefore, by moving the installation 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 not covered by the cover. This allows a highly soiled protective glass to be quickly replaced with a protective glass with a high level of cleanliness. Therefore, the shaping efficiency can be further improved. At the same time, the protective glass located 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 located in a position covered by the cover, this protective glass does not participate in shaping. Therefore, the protective glass with fumes attached can be cleaned after movement, thereby maintaining the cleanliness of the protective glass.

[0082] An example of the movement mechanism is a rotation mechanism that rotates the installation member around a rotation axis that is perpendicular to one surface of the installation member.

[0083] A protective glass cleaning system (1C) according to a seventh aspect of the present disclosure, in any of the first to fourth aspects, comprises a protective glass housing member (41) having a plurality of protective glass housing sections (42) formed therein that can individually house a plurality of the protective glasses, a covering position (P11) provided in the plurality of protective glass housing sections that covers 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 that exposes one side of the protective glass housed in the plurality of protective glass housing sections, and a slide mechanism that slides 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 the present disclosure includes a protective glass housing member having a plurality of protective glass housing sections each capable of housing a protective glass individually, 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 printing. 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 printing.

[0085] The present disclosure also includes a slide mechanism that slides the protective glass accommodated in the multiple protective glass accommodation units between a covered position and an exposed position. Therefore, when cleaning of the protective glass is required, the slide mechanism can be used to slide and exchange the protective glass in the covered position with the protective glass in the exposed position. This allows the protective glass in the covered position to be moved to the exposed position. This allows the protective glass with a high level of contamination to be quickly replaced with a protective glass with a high level of cleanliness. Therefore, the shaping efficiency can be further improved. At the same time, the protective glass in the exposed position can be moved to the covered position. Because the laser light is not irradiated onto the protective glass in the covered position, this protective glass does not participate in shaping. Therefore, the protective glass with fumes attached can be cleaned after movement, thereby maintaining the cleanliness of the protective glass. This is also more space-efficient than using a moving mechanism.

[0086] A protective glass cleaning method according to an eighth aspect of the present disclosure includes a modeling process in which an additive manufacturing apparatus irradiates a powder with laser light to melt and bond the powder to form a shaped object, and during the modeling process, cleaning of a protective glass that protects a focusing lens that focuses the laser light from dirt is performed at a predetermined timing during the modeling of the shaped object.

[0087] When a laser beam is irradiated onto a powder to form a part to be formed, fumes (metal vapor) are generated. If a large amount of fumes adhere to the protective glass, the laser beam may be absorbed or scattered by the fumes, resulting in defects such as poor fusion. Therefore, in the present disclosure, the protective glass is cleaned at a predetermined timing during the formation of the object in the forming process. In particular, in the present disclosure, the protective glass is cleaned during the formation process, rather than at the start or end of the formation, thereby preventing a large amount of fumes from adhering to the protective glass during the formation process and causing defects such as poor fusion due to the adhering fumes. This allows the cleanliness of the protective glass to be maintained during the formation process, thereby ensuring the quality of the formed product.

[0088] 2 Protective glass 10A, 10B, 10C Protective glass cleaning system 11 Cover 12 Opening 13 Rotating shaft 21 Protective glass part 31 Installation member 32 Support part 33 Protective glass installation part 41 Protective glass storage member 42 Protective glass storage part 43 Covering part 44 Opening 50 Control part 51 Determination part 101 Fume P1, P1' First position P2, P2' Second position P3 Third position P4 Fourth position P11 Covering position P12 Exposing position

Claims

1. A protective glass cleaning system provided in an additive manufacturing device that irradiates a powder with a laser beam to fuse the powder and form a model, the protective glass cleaning system comprising: a cleaning mechanism that cleans a protective glass that protects a focusing lens that focuses the laser beam from dirt; and a control unit that controls the cleaning mechanism, wherein the control unit controls the cleaning mechanism to clean the protective glass at a predetermined timing during the formation of the model.

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

3. The protective glass cleaning system of claim 1, further comprising a determination unit that determines the predetermined timing, 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 the additive manufacturing device.

4. A protective glass cleaning system as described in claim 1, further comprising a determination unit that determines the specified timing, wherein the determination unit determines the specified timing based on the product of the mass concentration of fumes scattered in the vicinity of the protective glass and the formation time.

5. A protective glass cleaning system as claimed in any one of claims 1 to 4, comprising: a cover that covers one side of the protective glass and has an opening that exposes a portion of the one side of the protective glass; and a movement mechanism that moves the protective glass and / or the cover so that the position of the opening that corresponds to the one side of the protective glass moves relatively.

6. A protective glass cleaning system as described in any one of claims 1 to 4, comprising: an installation member having a plurality of protective glass installation sections formed thereon, on which a plurality of the protective glasses can be installed individually; a cover that covers one side of at least one of the plurality of protective glasses installed on the plurality of protective glass installation sections; and a moving mechanism that moves the installation member and / or the cover so that the position of the cover corresponding to one side of the installation member moves relatively.

7. A protective glass cleaning system as described in any one of claims 1 to 4, comprising: a protective glass storage member formed with a plurality of protective glass storage sections capable of individually storing a plurality of the protective glasses; a covering position provided in the plurality of protective glass storage sections, which covers one side of the protective glasses stored in the plurality of protective glass storage sections with a covering section; an exposing position provided in the plurality of protective glass storage sections, which exposes one side of the protective glasses stored in the plurality of protective glass storage sections; and a sliding mechanism which slides the protective glasses stored in the plurality of protective glass storage sections between the covering position and the exposing position.

8. A protective glass cleaning method comprising a manufacturing process in which a laser beam is irradiated onto powder using an additive manufacturing device to fuse and bond the powder to form a molded object, and in the manufacturing process, cleaning a protective glass that protects a focusing lens that focuses the laser beam from dirt is performed at a predetermined timing during the manufacturing of the molded object.

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