Measurement device and additive manufacturing device

Abstract

A measurement device according to the present disclosure comprises a projection unit, an imaging unit, and an information processing unit. The projection unit has: a light source that emits light toward a measurement reference surface; a mask that allows transmission therethrough of light emitted from the light source and that generates a fringe pattern; and an actuator that moves the mask. The projection unit changes the phase of the fringe pattern by moving the mask. The imaging unit has an imager that acquires the amount of reflected light at each point on a projection surface on which the fringe pattern is projected from among the measurement reference surface and a surface of a measurement object. The information processing unit has: on the basis of the amount of the reflected light that is acquired a plurality of times by changing the phase of the fringe pattern, a reflected light-amount change measurement unit that measures, at each point on the projection surface, reflected light-amount change that occurs at each point on the projection surface in association with the phase change of the fringe pattern; and a height measurement unit that measures the height of each point on the surface of the object to be measured with respect to the measurement reference surface, on the basis of the reflected light-amount change at each said point on the projection surface.

Description

Measuring equipment and additive manufacturing equipment

[0001] This application claims priority to Japanese Patent Application No. 2024-004160, filed on January 15, 2024, the contents of which are incorporated herein by reference.

[0002] Three-dimensional additive manufacturing (3DAM) technology is known, which produces three-dimensional objects by irradiating a layer of powder with a beam such as a light beam or an electron beam to perform additive manufacturing. This type of additive manufacturing technology can cause deformation of the object due to the heat of the beam. Furthermore, spatter generated during the manufacturing process can remain, reducing the accuracy of the shape of the object. Furthermore, hollow defects can also occur inside the object.

[0003] Patent Literature 1 discloses an additive manufacturing device that detects these abnormalities that occur during a manufacturing operation. This additive manufacturing device has a projector that projects a fringe pattern onto a model. The additive manufacturing device detects irregularities in the model based on data acquired by capturing an image of the fringe pattern projected onto the model.

[0004] Japanese Patent Application Laid-Open No. 2019-173103

[0005] However, with conventional projectors, the resolution of the fringe pattern is low, making it sometimes impossible to measure the shape of a molded object with high accuracy. Furthermore, for one measurement point, it is necessary to capture the fringe pattern multiple times by changing the phase of the fringe pattern, but switching the phase of the fringe pattern takes time with a projector. This results in a lack of captured data, making it difficult to ensure the required measurement accuracy.

[0006] The present disclosure has been made to solve the above-described problems, and aims to provide a measuring device and an additive manufacturing device that can improve measurement accuracy.

[0007] In order to solve the above problems, a measurement device according to the present disclosure includes a projection unit that projects a fringe pattern onto a measurement reference surface and a surface of an object to be measured on the measurement reference surface, an imaging unit that images the fringe pattern projected onto the measurement reference surface and the surface of the object to be measured, and an information processing unit that processes information of the fringe pattern imaged by the imaging unit and measures the shape of the object to be measured, wherein the projection unit has a light source that irradiates light towards the measurement reference surface, a mask that transmits the light irradiated from the light source and generates the fringe pattern, and an actuator that moves the mask, The phase of the fringe pattern is changed by moving a mask, and the imaging unit has an imager that acquires the amount of reflected light at each point on the measurement reference surface and a projection surface on the surface of the object to be measured, onto which the fringe pattern is projected, and the information processing unit has a reflected light amount change measuring unit that measures the change in the amount of reflected light at each point on the projection surface due to the phase change of the fringe pattern based on the reflected light amount acquired multiple times at each point on the projection surface by changing the phase of the fringe pattern, and a height measuring unit that measures the height of each point on the surface of the object to be measured relative to the measurement reference surface based on the change in the amount of reflected light at each point on the projection surface.

[0008] The additive manufacturing apparatus according to the present disclosure comprises the above-mentioned measuring device, a stage having a manufacturing surface on which an object is additively manufactured, a powder supply unit that supplies powder onto the manufacturing surface, a coater that flattens the powder on the manufacturing surface to form a powder bed, and a head that irradiates a beam onto the powder bed on the manufacturing surface to sinter it, wherein the object and the powder bed are the objects to be measured, the manufacturing surface is the measurement reference surface, and the projection unit further has a projection lens arranged between the mask and the measurement reference surface, and the mask and the projection lens are arranged parallel to the measurement reference surface.

[0009] According to the measuring device and additive manufacturing device of the present disclosure, it is possible to improve measurement accuracy.

[0010] FIG. 1 is a configuration diagram of an additive manufacturing apparatus according to a first embodiment of the present disclosure. FIG. 2 is a functional block diagram of a manufacturing control unit according to a first embodiment of the present disclosure. FIG. 3 is a configuration diagram of a projection unit according to a first embodiment of the present disclosure. FIG. 4 is a schematic diagram of a fringe pattern according to a first embodiment of the present disclosure. FIG. 5 is a configuration diagram of an imaging unit according to a first embodiment of the present disclosure. FIG. 6 is a schematic diagram showing a measurement method according to a first embodiment of the present disclosure. FIG. 7 is a functional block diagram of an information processing unit according to a first embodiment of the present disclosure. FIG. 8 is a flowchart showing a procedure for additive manufacturing of one layer according to a first embodiment of the present disclosure. FIG. 9 is a flowchart showing a procedure for a measurement method according to a first embodiment of the present disclosure. FIG. 10 is a flowchart showing a procedure for measuring the height of a measurement object according to a first embodiment of the present disclosure. FIG. 11 is a diagram showing a change in the amount of reflected light at one measurement point according to the first embodiment of the present disclosure. FIG. 12 is a diagram showing a fringe pattern projected on a measurement reference surface according to a comparative example. FIG. 13 is a diagram showing a fringe pattern projected on a measurement reference surface according to the first embodiment of the present disclosure. FIG. 14 is a diagram showing a measurement reference surface imaged by an imaging unit according to a comparative example. FIG. 15 is a diagram showing a measurement reference surface imaged by an imaging unit according to a first embodiment of the present disclosure. FIG. 16 is a diagram showing a configuration diagram of an imaging unit according to a modified example of the present disclosure. FIG. 17 is a functional block diagram of an information processing unit according to a second embodiment of the present disclosure. FIG. 18 is a flowchart showing a procedure for a measurement method according to a second embodiment of the present disclosure. FIG. 10 is a diagram for explaining the movement of a measurement reference plane when creating a reflected light amount change table according to a second embodiment of the present disclosure. FIG. 11 is a diagram showing a reflected light amount change table for each height at a certain pixel according to a second embodiment of the present disclosure. FIG. 12 is a flowchart showing a procedure for measuring the height at one measurement point on a measurement object according to a second embodiment of the present disclosure. FIG. 13 is a schematic diagram showing a change in reflected light amount at one measurement point on a measurement object according to a second embodiment of the present disclosure. FIG. 14 is a diagram showing a hardware configuration according to an embodiment of the present disclosure.

[0011] First Embodiment An additive manufacturing apparatus 1 according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 15. Hereinafter, one horizontal direction will be referred to as the X direction, and the horizontal direction perpendicular to the X direction will be referred to as the Y direction. The up-down direction will be referred to as the Z direction. The Z direction is perpendicular to the X and Y directions.

[0012] 1 manufactures an object 2 by additive manufacturing (AM) technology. The additive manufacturing apparatus 1 includes a chamber 3, a cylinder 4, a stage 5, a powder supply unit 6, a coater 7, a head 8, a manufacturing control unit 20, and a measuring device 9.

[0013] (Chamber) The chamber 3 has a housing 3a, a beam window 3b, a projection window 3c, and an imaging window 3d. The housing 3a houses a cylinder 4, a stage 5, a powder supply unit 6, and a coater 7 inside. The beam window 3b is provided in the center of the top of the housing 3a. The projection window 3c and the imaging window 3d are provided in the top of the housing 3a. The projection window 3c and the imaging window 3d face each other in the horizontal direction, with the beam window 3b in between.

[0014] (Cylinder) The cylinder 4 is formed in a cylindrical shape that extends in the vertical direction. The stage 5 is housed inside the cylinder 4.

[0015] (Stage) The stage 5 is formed in the shape of a flat plate extending horizontally. The stage 5 has a modeling surface 5a on its upper surface. The modeling surface 5a extends horizontally. The model 2 is layer-by-layer manufactured on the modeling surface 5a. The stage 5 is provided so as to be movable in the up and down direction along the cylinder 4. In other words, the height of the modeling surface 5a can be changed.

[0016] (Powder Supply Unit) The powder supply unit 6 supplies powder 6a onto the modeling surface 5a.

[0017] (Coater) The coater 7 moves horizontally to flatten the powder 6a supplied onto the modeling surface 5a, thereby laying a powder bed 6b on the modeling surface 5a.

[0018] (Head) The head 8 is located outside the chamber 3. The head 8 is located directly above the center of the build surface 5a, with the beam window 3b in between. The head 8 irradiates a beam 8a, such as a light beam or an electron beam, onto the powder bed 6b on the build surface 5a. This beam 8a passes through the beam window 3b and is irradiated onto the powder bed 6b. The powder bed 6b irradiated with the beam 8a is sintered. As a result, the object 2 is built on the build surface 5a.

[0019] (Modeling Control Unit) As shown in FIG. 2, the modeling control unit 20 has the functions of a stage control unit 21, a powder supply control unit 22, a coater control unit 23, and a head control unit 24. The stage control unit 21 controls the stage 5 and sets the height of the modeling surface 5a. The powder supply control unit 22 controls the powder supply unit 6 and causes the powder supply unit 6 to supply powder 6a onto the modeling surface 5a. The coater control unit 23 controls the coater 7 and causes the coater 7 to level the powder 6a on the modeling surface 5a and lay a powder bed 6b. The head control unit 24 controls the head 8 and causes the head 8 to irradiate the beam 8a onto the powder bed 6b on the modeling surface 5a.

[0020] (Measuring Device) The measuring device 9 is a device that measures the surface shapes of the object 2 and the powder bed 6b by the fringe projection method, using the object-to-be-formed surface 5a as a measurement reference surface 10. Hereinafter, the object to be measured by the measuring device 9 will be referred to as the object to be measured 11. The object to be measured 11 is, for example, the object 2 or the powder bed 6b immediately after being laid. The measuring device 9 has a projection unit 30, an imaging unit 40, and an information processing unit 50.

[0021] (Projection Unit) The projection unit 30 is located outside the chamber 3. The projection unit 30 is located above the measurement reference surface 10, with a projection window 3c in between. The projection unit 30 is also located at an angle with respect to the measurement reference surface 10, at a position shifted from directly above the measurement reference surface 10 so as not to interfere with the head 8. The projection unit 30 projects a fringe pattern 36 (see FIG. 4 ) onto the measurement reference surface 10 and onto the surface of the object to be measured 11 on the measurement reference surface 10. In the following description, the surface of the measurement reference surface 10 or the surface of the object to be measured 11 onto which the fringe pattern 36 is projected may be referred to as the projection surface 12.

[0022] As shown in FIG. 3, the projection unit 30 includes a light source 32, a mask 33, an actuator 34, and a projection lens 35.

[0023] (Light Source) The light source 32 emits radial light toward the measurement reference surface 10. Here, a straight line connecting the center of the light source 32 and the center of a projection lens 35 (described later) is the optical axis O1 of the light source 32. This optical axis O1 passes through the center 10a of the measurement reference surface 10.

[0024] (Mask) The mask 33 is disposed on the optical axis O1 of the light source 32, between the light source 32 and the measurement reference surface 10. The mask 33 is formed by drawing a plurality of striped patterns 33b on a transparent substrate 33a made of a light-transmitting material, such as glass. The striped patterns 33b extend in one direction (e.g., the X direction). As shown in FIG. 4 , a striped fringe pattern 36 is generated when light emitted from the light source 32 passes through the mask 33. The fringe pattern 36 is a so-called sinusoidal pattern, and the amount of reflected light of the fringe pattern 36 changes sinusoidally depending on the measurement position (phase).

[0025] (Actuator) The actuator 34 moves the mask 33 in one direction (for example, the Y direction). The projection unit 30 changes the phase of the fringe pattern 36 by moving the mask 33 using the actuator 34.

[0026] (Projection Lens) The projection lens 35 is disposed on the optical axis O1 of the light source 32 and between the mask 33 and the measurement reference surface 10 .

[0027] (Arrangement of Mask and Projection Lens) The mask 33 is inclined with respect to the optical axis O1 of the light source 32. That is, the mask 33 is arranged so as to intersect with a plane perpendicular to the optical axis O1 of the light source 32. In this embodiment, the mask 33 and the projection lens 35 are arranged parallel to the measurement reference surface 10 so as to form a shift lens optical system.

[0028] (Imaging Unit) The imaging unit 40 is disposed outside the chamber 3. The imaging unit 40 is disposed above the build surface 5a (measurement reference surface 10) across the imaging window 3d. To prevent the imaging unit 40 from interfering with the head 8, the projection unit 30 is disposed at an angle relative to the measurement reference surface 10, offset from directly above the measurement reference surface 10. The imaging unit 40 is disposed horizontally opposite the projection unit 30 across the head 8. The imaging unit 40 captures images of the fringe pattern 36 projected onto the measurement reference surface 10 and the surface of the object 11 through the imaging window 3d. In this embodiment, the imaging unit 40 continuously captures images of the fringe pattern 36 while the mask 33 is moving. As shown in FIG. 5 , the imaging unit 40 includes a camera 41 and a light-receiving lens 42.

[0029] (Camera) The camera 41 has an imager 44 .

[0030] (Imager) The imager 44 acquires the amount of reflected light at each point on the projection surface 12 onto which the fringe pattern 36 is projected. As shown in Fig. 6, the imager 44 has a plurality of pixels 45. Each of the plurality of pixels 45 acquires the amount of reflected light at one point on the projection surface 12.

[0031] (Light-Receiving Lens) The light-receiving lens 42 is disposed on an optical axis O2 connecting the center 44b of the imager 44 and the center of the measurement reference surface 10, between the imager 44 and the measurement reference surface 10.

[0032] (Arrangement of Imager and Light-Receiving Lens) In this embodiment, the imager 44 and the light-receiving lens 42 are arranged parallel to the measurement reference surface 10 so as to form a shift lens optical system.

[0033] (Information Processing Section) The information processing section 50 processes information on the fringe pattern 36 captured by the imaging section 40, and measures the shape of the measurement object 11. As shown in Fig. 7 , the information processing section 50 has the functions of a projection control section 51, an imaging control section 52, a memory section 53, a reflected light amount change measurement section 54, a phase measurement section 55, a height measurement section 56, and a surface shape measurement section 57.

[0034] (Projection Control Unit) The projection control unit 51 controls the projection unit 30 to project the fringe pattern 36 onto the measurement reference surface 10. Furthermore, the projection control unit 51 moves the mask 33 using the actuator 34 to change the phase of the fringe pattern 36.

[0035] (Image Capture Control Unit) The image capture control unit 52 controls the image capture unit 40 to cause the image capture unit 40 to capture an image of the fringe pattern 36 projected onto the projection surface 12 .

[0036] (Memory unit) The memory unit 53 stores information such as the image of the fringe pattern 36 captured by the imaging unit 40, the phase of the fringe pattern 36 at each point on the projection surface 12 acquired by the phase measurement unit 55 described later, and the height of the surface of the object to be measured 11 acquired by the height measurement unit 56 described later.

[0037] (Reflected light amount change measuring unit) The reflected light amount change measuring unit 54 measures the change in the reflected light amount at each point on the projection surface 12 due to the phase change of the fringe pattern 36, based on the reflected light amount obtained multiple times at each point on the projection surface 12 by changing the phase of the fringe pattern 36.

[0038] (Phase Measurement Unit) The phase measurement unit 55 measures the phase of the fringe pattern 36 at each point on the projection surface 12 based on the change in the amount of reflected light measured by the reflected light amount change measurement unit 54 .

[0039] (Height Measuring Unit) The height measuring unit 56 measures the height of each point on the surface of the object to be measured 11 relative to the measurement reference plane 10, based on a change in the amount of reflected light at each point on the projection plane 12. In this embodiment, the height measuring unit 56 further performs arithmetic processing on the phase measured by the phase measuring unit 55 based on the change in the amount of reflected light, and measures the height of each point on the surface of the object to be measured 11.

[0040] (Surface Shape Measurement Unit) The surface shape measurement unit 57 measures the surface shape of the object 2 by collecting the heights of each point on the surface of the measurement object 11. For example, the surface shape measurement unit 57 specifies the surface shape of the measurement object 11 by plotting each point on the surface of the measurement object 11 in a virtual space. The surface shape of the measurement object 11 here refers to the shape of the surface of the measurement object 11 that is not in contact with the measurement reference surface 10 and is exposed upward.

[0041] (Additive Manufacturing Procedure) The additive manufacturing procedure will be described below with reference to the flow chart in FIG. 8 . First, the stage control unit 21 moves the stage 5 in the −Z direction (step S11). This adjusts the build surface 5a to an appropriate height. After step S11, the powder supply control unit 22 controls the powder supply unit 6 to supply powder 6a to the build surface 5a (step S12). After step S12, the coater control unit 23 controls the coater 7 to level the powder 6a on the build surface 5a and lay a powder bed 6b (step S13). After step S13, the head control unit 24 controls the head 8 to irradiate the powder bed 6b on the build surface 5a with a beam 8a (step S14). This sinters the powder bed 6b, forming a sintered layer. By repeating steps S11 to S13, multiple sintered layers are stacked in the Z direction on the build surface 5a. In this way, the object 2 is layer-by-layer manufactured on the manufacturing surface 5a.

[0042] (Procedure of Measurement Method) Hereinafter, the procedure of the method for measuring the shape of the object to be measured 11 (e.g., the molded object 2) using the measurement device 9 will be described with reference to the flow in Fig. 9. In this embodiment, the measurement device 9 measures the shape of the object to be measured 11 using a phase shift method. First, the measurement device 9 measures the height of each point on the object to be measured 11 (step S21). Hereinafter, the procedure of step S21 will be described in detail with reference to the flow in Fig. 10.

[0043] As shown in Figure 6, the procedure of step S21 will be described using an example in which the height of one measurement point P1 on the surface of the measurement object 11 is measured. Figure 6 illustrates the camera base point PA that constitutes the imaging unit 40, and the projection base point PB of the fringe pattern 36 projected by the projection unit 30. The line connecting the camera base point PA and the projection base point PB is defined as the base line L1. The line passing through the camera base point PA and the measurement point P1 is defined as the camera line of sight L2. The intersection of the camera line of sight L2 and the measurement reference surface 10 is defined as the reference point PO. In addition, the camera line of sight L2 passes through the imager 44. Of the multiple pixels 45 that constitute the imager 44, the pixel 45 that the camera line of sight L2 passes through is defined as the corresponding pixel 45a.

[0044] First, the projection control unit 51 causes the projection unit 30 to project a fringe pattern 36 onto the measurement reference surface 10 and the surface (projection surface 12) of the object to be measured 11 (step S31). This fringe pattern 36 is a sine wave pattern in which the amount of reflected light varies sinusoidally depending on the phase. In step S31, the phase of the reference point PO in the fringe pattern 36 irradiated onto the measurement point P1 is set to 0.

[0045] Thereafter, the imaging control unit 52 causes the imaging unit 40 to capture an image of the fringe pattern 36 projected onto the projection surface 12 (step S32). In step S32, the amount of reflected light at measurement point P1 is acquired by the corresponding pixel 45a. In step S32, the projection control unit 51 drives the actuator 34 to move the mask 33. This changes the phase of the fringe pattern 36, and the amount of reflected light at measurement point P1 changes in accordance with the phase change of the fringe pattern 36. At this time, the imaging unit 40 continuously captures images of the fringe pattern 36 while the mask 33 is moving. This causes the amount of reflected light at measurement point P1 at each time to be acquired by the corresponding pixel 45a. The amount of reflected light at measurement point P1 is acquired at least four times. The multiple measurement values ​​of the amount of reflected light at measurement point P1 acquired by the corresponding pixel 45a are stored in the memory unit 53.

[0046] After step S32, the reflected light amount change measuring unit 54 measures the measured value I ０ ~I ７ 11, the reflected light amount change measuring unit 54 displays a plurality of measured values ​​of the reflected light amount at the measurement point P1 at each time on a graph with the horizontal axis representing time and the vertical axis representing the reflected light amount (measured value I ０ ~I ７ ) and plot these multiple measured values ​​I ０ ~I ７ This fitted sine wave curve represents the change in the reflected light amount at the measurement point P1. The maximum value of the sine wave curve is the maximum reflected light amount I Ｈ , the minimum value of the sine wave curve is the minimum reflected light amount I Ｌ represents.

[0047] After step S33, the phase measurement unit 55 measures the phase φ of the measurement point P1 relative to the reference point PO based on the change in the amount of reflected light at the measurement point P1 (step S34). The phase measurement unit 55 calculates the phase φ of the measurement point P1 from the amount of deviation on the horizontal axis between the sine wave curve representing the change in the amount of reflected light at the reference point PO and the sine wave curve representing the change in the amount of reflected light at the measurement point P1.

[0048] The reflected light amount change measuring unit 54 plots the measured value I of the reflected light amount at the measurement point P1 for each phase shift amount of the fringe pattern 36 on a graph with the phase shift amount on the horizontal axis and the reflected light amount on the vertical axis (a graph in FIG. 11 with the phase shift on the horizontal axis). ０ ~I ７ and plot these multiple measured values ​​I ０ ~I ７ Alternatively, a sine wave curve passing through the reference point PO may be fitted. In this case, for example, the projection control unit 51 needs to calculate the amount of phase shift from the amount of movement from the actuator. The calculated amount of phase shift is transmitted from the projection control unit 51 to the reflected light amount change measurement unit 54. This allows the reflected light amount change measurement unit 54 to plot the measured value of the reflected light amount at the measurement point P1 for each amount of phase shift. In this case, the phase measurement unit 55 determines the phase difference between the sine wave curve representing the change in the reflected light amount at the reference point PO and the sine wave curve representing the change in the reflected light amount at the measurement point P1 as the phase φ of the measurement point P1.

[0049] Although the method of determining the phase of a measurement point by performing sine wave fitting has been described, the present invention is not limited to this. This method is merely one example of a method of determining the phase of a measurement point. Another method of determining the phase of a measurement point is to calculate the initial phase using arithmetic operations.

[0050] After step S34, the height measurement unit 56 calculates the height of the measurement point P1 relative to the measurement reference surface 10 based on the phase φ of the measurement point P1 (step S35). In step S35, the height measurement unit 56 performs calculations using the principle of triangulation based on the length d1 of the base line L1, the angle θA of the measurement point P1 as viewed from the camera base point PA (the angle θA between the base line L1 and the line connecting the camera base point PA and the measurement point P1), the angle θB of the measurement point P1 as viewed from the projection base point PB (the angle θB between the base line L1 and the line connecting the projection base point PB and the measurement point P1), and the phase φ of the measurement point P1, to determine the perpendicular distance d2 between the measurement point P1 and the base line L1. Here, "perpendicular distance" refers to the shortest distance between a point and a line. The height measurement unit 56 then measures the height of the measurement point P1 relative to the measurement reference surface 10 based on the perpendicular distance d2 between the measurement point P1 and the base line L1. Through the above procedure, measurement of the height of one measurement point P1 of the object to be measured 11 is completed.

[0051] The above-described procedures of steps S31 to S35 are performed for each point on the surface of the measurement object 11. This measures the height of each point on the surface of the measurement object 11. The height of each point on the surface of the measurement object 11 is stored in the storage unit 53. With the above procedures, height measurement at each point on the surface of the measurement object 11 is completed (step S21).

[0052] After step S21, the surface shape measurement unit 57 aggregates the heights of each point on the surface of the object 11 measured in step S21 to measure the surface shape of the object 11 (step S22). For example, the surface shape measurement unit 57 specifies the surface shape of the object 11 by plotting each point on the surface of the object 11 in a virtual space. The above procedure completes the measurement of the shape of the object 11. Note that the surface shape of the powder bed 6b before being irradiated with the beam 8a can be measured using a similar procedure.

[0053] (Effects) The measuring device 9 and additive manufacturing device 1 of this embodiment provide the following effects. This embodiment includes a projection unit 30, an imaging unit 40, and an information processing unit 50. The projection unit 30 projects a fringe pattern 36 onto the measurement reference surface 10 and the surface of the object to be measured 11 on the measurement reference surface 10. The imaging unit 40 images the fringe pattern 36 projected onto the measurement reference surface 10 and the surface of the object to be measured 11. The information processing unit 50 processes information on the fringe pattern 36 imaged by the imaging unit 40 and measures the shape of the object to be measured 11. The projection unit 30 includes a light source 32, a mask 33, and an actuator 34. The light source 32 irradiates light toward the measurement reference surface 10. The mask 33 transmits the light irradiated from the light source 32 to generate the fringe pattern 36. The actuator 34 moves the mask 33. The projection unit 30 changes the phase of the fringe pattern 36 by moving the mask 33. The imaging unit 40 has an imager 44 that acquires the amount of reflected light at each point on the projection surface 12, which is one of the measurement reference surface 10 and the surface of the object to be measured 11 and onto which the fringe pattern 36 is projected. The information processing unit 50 has a reflected light amount change measurement unit 54 and a height measurement unit 56. The reflected light amount change measurement unit 54 measures the change in the amount of reflected light at each point on the projection surface 12 that accompanies the phase change of the fringe pattern 36, based on the amount of reflected light acquired multiple times at each point on the projection surface 12 while changing the phase of the fringe pattern 36. The height measurement unit 56 measures the height of each point on the surface of the object to be measured 11 relative to the measurement reference surface 10, based on the change in the amount of reflected light at each point on the projection surface 12.

[0054] With the above configuration, the projection unit 30 can change the phase of the fringe pattern 36 simply by moving the mask 33. This reduces the time required to change the phase of the fringe pattern 36. This increases the number of times the amount of reflected light is measured at each point on the projection surface 12 per unit time. In this embodiment, the measurement device 9 measures the height of each point on the surface of the object 11 based on changes in the amount of reflected light, thereby enabling accurate measurement of the shape of the object 11. Furthermore, as described above, the reduction in the time required to change the phase of the fringe pattern 36 reduces the time required to measure the shape of the object 11. Furthermore, in this embodiment, the projection unit 30 can change the phase of the fringe pattern 36 with a simple configuration including the light source 32, the mask 33, and the actuator 34, thereby enabling the projection unit 30 to be miniaturized.

[0055] In this embodiment, the image capturing section 40 continuously captures images of the fringe pattern 36 while the mask 33 is moving.

[0056] This reduces the time required to measure the change in the amount of reflected light compared to, for example, a conventional case in which a projector projects a fringe pattern while changing the projection screen, and thus further reduces the time required to measure the shape of the measurement object 11 (in this embodiment, the model 2 or the powder bed 6b).

[0057] In this embodiment, the mask 33 is inclined with respect to the optical axis O1 of the light source 32 so as to intersect with a plane perpendicular to the optical axis O1 of the light source 32.

[0058] For example, even if the optical axis O1 of the light source 32 is positioned at an angle relative to the normal to the measurement reference surface 10 in order to leave space above the measurement reference surface 10, the distortion of the fringe pattern 36 projected onto the projection surface 12 can be reduced by adjusting the angle of inclination of the mask 33 relative to the optical axis O1 of the light source 32.

[0059] In this embodiment, the additive manufacturing apparatus 1 includes a measuring device 9, a stage 5 having a manufacturing surface 5a on which the object 2 is additively manufactured, a powder supply unit 6 that supplies powder 6a onto the manufacturing surface 5a, a coater 7 that flattenes the powder 6a on the manufacturing surface 5a to form a powder bed 6b, and a head 8 that irradiates a beam 8a onto the powder bed 6b on the manufacturing surface 5a to sinter it. In this embodiment, the object 2 and the powder bed 6b are the object to be measured 11, and the manufacturing surface 5a is the measurement reference surface 10. The projection unit 30 further includes a projection lens 35 that is arranged between a mask 33 and the measurement reference surface 10. The mask 33 and the projection lens 35 are arranged parallel to the measurement reference surface 10.

[0060] To prevent the projection unit 30 from interfering with the head 8, the projection unit 30 is positioned at a position offset from directly above the build surface 5a (measurement reference surface 10) and tilted with respect to the measurement reference surface 10. In this case, if, for example, the mask 33 and projection lens 35 intersect perpendicularly with the optical axis O1 and are tilted with respect to the measurement reference surface 10, distortion will occur in the fringe pattern 36 projected onto the measurement reference surface 10, as shown in FIG. 12 . In contrast, in this embodiment, by positioning the mask 33 and projection lens 35 parallel to the measurement reference surface 10, distortion of the fringe pattern 36 projected onto the measurement reference surface 10 is reduced, as shown in FIG. 13 . This makes the fringe pattern 36 uniform across the entire surface of the measurement reference surface 10, further improving measurement accuracy.

[0061] In this embodiment, the imaging unit 40 further includes a light-receiving lens 42 disposed between the imager 44 and the measurement reference surface 10. The imager 44 and the light-receiving lens 42 are disposed parallel to the measurement reference surface 10.

[0062] In order to prevent the projection unit 30 from interfering with the head 8, the projection unit 30 is positioned at a position shifted from directly above the printing surface 5a (measurement reference surface 10) and tilted with respect to the measurement reference surface 10. In this case, for example, if the imager 44 and the light-receiving lens 42 are tilted with respect to the measurement reference surface 10, distortion will occur in the image 13 of the measurement reference surface 10 acquired by the imaging unit 40, as shown in FIG. 14. In contrast, in this embodiment, the imager 44 and the light-receiving lens 42 are positioned parallel to the measurement reference surface 10, so that the imaging unit 40 can image the measurement reference surface 10 without distortion, as shown in FIG. 15. This further improves measurement accuracy.

[0063] 16, the imager 44, the light-receiving lens 42, and the measurement reference surface 10 may be arranged to form a so-called tilt lens optical system. In this case, the imager 44, the light-receiving lens 42, and the measurement reference surface 10 are arranged along three reference lines L3 extending radially from a predetermined point. Furthermore, the center 42a of the light-receiving lens 42 is arranged on a straight line (optical axis O2) connecting the center 44b of the imager 44 and the center 10a of the measurement reference surface 10.

[0064] In a shift lens optical system, if the image circle of the light-receiving lens 42 is small, it is necessary to tilt the entire imaging unit 40 and shift the image circle within an allowable range. Tilting the imaging unit 40 changes the vertical distance from the imaging center to the object plane. In this case, if the depth of field of the imaging unit 40 is narrow, the imaging unit 40 cannot focus on the entire area to be imaged. The depth of field can be widened by narrowing the iris of the imaging unit 40, but narrowing the iris darkens the image captured by the imaging unit 40, reducing measurement accuracy. In contrast, by arranging the components of the imaging unit 40 as described above, it is possible to focus on the entire field of view of the imaging unit 40 without narrowing the iris. This improves measurement accuracy.

[0065] Second Embodiment An additive manufacturing apparatus 1 according to a second embodiment of the present disclosure will be described below with reference to Figures 17 to 24. Of the configurations of the second embodiment, configurations that are common to the above-described embodiments will be given the same names and reference numerals, and descriptions thereof will be omitted as appropriate.

[0066] 17 , the information processing unit 50 has the functions of the above-mentioned projection control unit 51, imaging control unit 52, storage unit 53, reflected light amount change measurement unit 54, height measurement unit 56, and surface shape measurement unit 57. Furthermore, the information processing unit 50 has the function of a reflected light amount change table creation unit 58.

[0067] (Reflected light intensity change table creation unit) The reflected light intensity change table creation unit 58 creates a reflected light intensity change table that records the change in reflected light intensity at multiple height positions on the measurement reference surface 10 for each pixel 45 when the object to be measured 11 is not placed on the measurement reference surface 10.

[0068] (Height measurement unit) The height measurement unit 56 of this embodiment identifies, for a single measurement point on the surface of the object to be measured 11, a specific change in the amount of reflected light that is closest to the change in the amount of reflected light acquired by the reflected light amount change measurement unit 54 based on the amount of reflected light acquired at a single pixel 45 corresponding to that single measurement point, from the multiple changes in the amount of reflected light recorded in the reflected light amount change table for that single pixel 45, and determines the height corresponding to the specific change in the amount of reflected light as the height of that single measurement point on the surface of the object to be measured 11.

[0069] (Procedure of Measurement Method) Below, with reference to the flow in Fig. 18, the procedure of the method for measuring the shape of the measurement object 11 (e.g., the molded object 2) using the measurement device 9 will be described. First, a reflected light amount change table is created (step S41). The reflected light amount change table records the change in the reflected light amount for each pixel 45 when the height of the measurement reference surface 10 is changed. Below, with reference to the flow in Fig. 19, the procedure of step S41 will be described in detail.

[0070] First, as shown in FIG. 20 , without the object 11 being placed on the measurement reference surface 10 (printing surface 5a), the stage 5 is moved to a predetermined position to set the height of the measurement reference surface 10 (step S51). Then, a fringe pattern 36 is projected onto the measurement reference surface 10 (step S52). The imaging unit 40 then captures an image of the fringe pattern 36 projected onto the measurement reference surface 10 (step S53). In step S53, the projection control unit 51 drives the actuator 34 to move the mask 33. After step S53, the change in the amount of reflected light is measured for each pixel 45 (step S54). In steps S52 to S54, the change in the amount of reflected light is measured for each pixel 45 using the same procedure as steps S31 to S33 in the first embodiment. The change in the amount of reflected light for each pixel 45 measured in step S54 is stored in the storage unit 53 (step S55).

[0071] After step S55, if measurement of the change in the amount of reflected light has not been completed at all heights (step S56; NO), the process returns to step S51, the height of the measurement reference surface 10 is changed, and the procedures from step S52 to step S55 are repeated.

[0072] After step S55, if the measurement of the change in the amount of reflected light has been completed at all heights (step S56; YES), the reflected light amount change table creation unit 58 creates a reflected light amount change table (step S57). With the above procedure, step S41 is completed.

[0073] In step S41 described above, a reflected light amount change table such as that shown in FIG. 21 is created. FIG. 21 is a reflected light amount change table for each height of one pixel 45b among the multiple pixels 45. In the example of FIG. 21, for that one pixel 45b, the change in reflected light amount at each height position (z) when the measurement reference surface 10 is moved upward and downward on the order of μm relative to a reference height z=0 is recorded. Note that this reference height (z=0) is the height position of the measurement reference surface 10 when the height of the measurement object 11 is measured in the subsequent step S42, and is set in advance before step S41.

[0074] After step S41, the height of each point on the measurement object 11 is measured (step S42). The procedure of step S42 will be described in detail below with reference to the flow of FIG.

[0075] As shown in Figure 23, the procedure of step S42 will be explained using an example in which the height of the measurement reference surface 10 is set to reference height z = 0, one pixel 45b acquires the amount of reflected light from one measurement point P2 on the surface of the object to be measured 11, and measures the height of the measurement point P2.

[0076] First, the projection control unit 51 causes the projection unit 30 to project the fringe pattern 36 onto the measurement reference surface 10 and the surface (projection surface 12) of the object 11 (step S61). Then, the imaging control unit 52 causes the imaging unit 40 to capture the fringe pattern 36 projected onto the projection surface 12 (step S62). In step S62, the amount of reflected light at measurement point P2 is measured multiple times at one pixel 45b corresponding to measurement point P2 by changing the phase of the fringe pattern 36. After step S62, the reflected light amount change measurement unit 54 measures the change in the amount of reflected light at each pixel 45 based on the multiple measurement values ​​measured in step S62 (step S63). These steps S61 to S63 are performed in the same procedure as steps S31 to S33 in the first embodiment described above, and data on the change in the amount of reflected light as shown in FIG. 24 is obtained for the pixel 45b from which the amount of reflected light at measurement point P2 was acquired.

[0077] Then, the reflected light amount change table created in step S41 is compared with the data of the reflected light amount change measured in step S63 to measure the height of measurement point P2 (step S64). Specifically, in step S64, the height measurement unit 56 identifies, from the multiple reflected light amount changes recorded in the reflected light amount change table shown in FIG. 21, a specific reflected light amount change A that is closest to the reflected light amount change (see FIG. 24) measured based on the reflected light amount at measurement point P2 acquired by one pixel 45b. The height measurement unit 56 then determines the height corresponding to the specific reflected light amount change A as the height at measurement point P2 on the surface of the measurement object 11. In the illustrated example, the reflected light amount change at z = +20 μm recorded in the reflected light amount change table (see FIG. 21) is the specific reflected light amount change A that is closest to the reflected light amount change at measurement point P2 (see FIG. 24). That is, the height of measurement point P2 is identified as z = +20 μm. Through the above procedure, measurement of the height of one measurement point P2 of the object to be measured 11 is completed.

[0078] The above-described procedures of steps S61 to S64 are performed for each point on the surface of the object to be measured 11. This measures the height of each point on the surface of the object to be measured 11. The height of each point on the surface of the object to be measured 11 is stored in the storage unit 53. With the above procedures, height measurement at each point on the surface of the object to be measured 11 is completed (step S42).

[0079] After step S42, the surface shape measurement unit 57 aggregates the heights of each point on the surface of the object 11 measured in step S42 and measures the surface shape of the object 11 (step S43). For example, the surface shape measurement unit 57 specifies the surface shape of the object 11 by plotting each point on the surface of the object 11 in a virtual space. The above procedure completes the measurement of the shape of the object 11. Note that the surface shape of the powder bed 6b before being irradiated with the beam 8a can be measured using a similar procedure.

[0080] (Effects) The measurement device 9 of this embodiment has the following effects. In this embodiment, the imager 44 has a plurality of pixels 45, each of which acquires the amount of reflected light at a point on the projection surface 12. The information processing unit 50 further has a reflected light amount change table creation unit 58 that creates, for each pixel 45, a reflected light amount change table that records changes in the amount of reflected light at a plurality of height positions on the measurement reference surface 10, when the object to be measured 11 is not placed on the measurement reference surface 10. The height measurement unit 56 identifies, for a single measurement point on the surface of the object to be measured 11, a specific reflected light amount change A that is closest to the reflected light amount change acquired by the reflected light amount change measurement unit 54 based on the reflected light amount acquired at a pixel 45 corresponding to the single measurement point, from the multiple reflected light amount changes recorded in the reflected light amount change table for the single pixel 45, and determines the height corresponding to the specific reflected light amount change A as the height of the single measurement point on the surface of the object to be measured 11.

[0081] The measurement device 9 of this embodiment can measure the height of the surface of the object 11 by simply comparing the change in the amount of reflected light in a previously acquired reflected light change table with the change in the amount of reflected light on the surface of the object 11. Therefore, the measurement device 9 can measure the height of each point on the surface of the object 11 without performing any further calculations on the measured change in the amount of reflected light. This allows the height of each point on the surface of the object 11 to be measured with high accuracy, regardless of the shape of the fringe pattern 36, even if the fringe pattern 36 is distorted. Furthermore, for example, if the actuator 34 is driven trapezoidally, the amount of movement of the actuator 34 becomes non-uniform during the acceleration and deceleration periods of the actuator 34. Even if the fringe pattern 36 is distorted due to such non-uniformity in the amount of movement of the actuator 34, this embodiment makes it possible to accurately measure the height of each point on the surface of the object 11.

[0082] (Hardware Configuration) The forming control unit 20 and the information processing unit 50 in the above-described embodiments and modifications are implemented in a computer 1100 shown in Fig. 25. Fig. 25 is a schematic block diagram showing the configuration of a computer according to each embodiment. The computer 1100 includes a processor 1110, a main memory 1120, a storage 1130, and an interface 1140.

[0083] The operations of the above-mentioned functional units of the forming control unit 20 and the information processing unit 50 are stored in the form of a program in the storage 1130. The processor 1110 reads the program from the storage 1130, loads it into the main memory 1120, and executes the above-mentioned processing in accordance with the program. The processor 1110 also allocates a storage area in the main memory 1120 in accordance with the program.

[0084] The program may be for realizing some of the functions to be performed by the computer 1100. For example, the program may be combined with other programs already stored in the storage 1130 or other programs implemented in other devices to perform the functions. Furthermore, the computer 1100 may include a custom large-scale integrated circuit (LSI) such as a programmable logic device (PLD) in addition to or instead of the above configuration. Examples of PLDs include programmable array logic (PAL), generic array logic (GAL), complex programmable logic device (CPLD), and field programmable gate array (FPGA). In this case, some or all of the functions realized by the processor 1110 may be realized by the integrated circuit.

[0085] Examples of storage 1130 include a magnetic disk, a magneto-optical disk, and a semiconductor memory. Storage 1130 may be an internal medium directly connected to the bus of computer 1100, or an external medium connected to computer 1100 via interface 1140 or a communication line. Furthermore, when this program is distributed to computer 1100 via a communication line, computer 1100 that receives the program may load the program into main memory 1120 and execute the above-mentioned processing. Storage 1130 may also be a non-transitory tangible storage medium.

[0086] The program may also be a program for realizing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in storage 1130.

[0087] (Other Embodiments) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within the scope that does not deviate from the gist of the present disclosure are also included.

[0088] In the above embodiment, the measuring device 9 measures the shapes of the object 2 and the powder bed 6b manufactured by the additive manufacturing apparatus 1, but this is not limiting. For example, the measuring device 9 may be used to measure the shape of an object manufactured by an external device.

[0089] In the above embodiment, the case where the projection unit 30 and the image capture unit 40 are provided outside the chamber 3 has been described, but this is not limiting. The projection unit 30 and the image capture unit 40 may also be provided inside the chamber 3.

[0090] In the above embodiment, the case where one projection lens 35 is provided in the projection unit 30 has been described, but this is not limitative. A plurality of projection lenses 35 may be provided in the projection unit 30.

[0091] In the above embodiment, the case where one light receiving lens 42 is provided in the imaging unit 40 has been described, but this is not limitative. The imaging unit 40 may be provided with a plurality of light receiving lenses 42.

[0092] In the above embodiment, the projection unit 30 projects a sine wave pattern, but this is not limiting. The pattern projected by the projection unit 30 may be any pattern for which the phase can be calculated. For example, the projection unit 30 may project a square wave pattern.

[0093] <Additional Notes> The measuring device 9 and the additive manufacturing device 1 described in each embodiment can be understood, for example, as follows.

[0094] (1) A measurement device 9 according to a first aspect includes a projection unit 30 that projects a fringe pattern 36 onto a measurement reference surface 10 and a surface of an object to be measured 11 on the measurement reference surface 10, an imaging unit 40 that images the fringe pattern 36 projected onto the measurement reference surface 10 and the surface of the object to be measured 11, and an information processing unit 50 that processes information of the fringe pattern 36 imaged by the imaging unit 40 and measures the shape of the object to be measured 11, and the projection unit 30 includes a light source 32 that irradiates light toward the measurement reference surface 10, a mask 33 that transmits the light irradiated from the light source 32 and generates the fringe pattern 36, and an actuator 34 that moves the mask 33, and the projection unit 30 The phase of the fringe pattern 36 is changed by moving the mask 33, and the imaging unit 40 has an imager 44 that acquires the amount of reflected light at each point on the projection surface 12 onto which the fringe pattern 36 is projected, which is one of the measurement reference surface 10 and the surface of the measured object 11, and the information processing unit 50 has a reflected light amount change measuring unit 54 that measures the change in the amount of reflected light at each point on the projection surface 12 due to the phase change of the fringe pattern 36 based on the reflected light amount acquired multiple times at each point on the projection surface 12 by changing the phase of the fringe pattern 36, and a height measuring unit 56 that measures the height of each point on the surface of the measured object 11 relative to the measurement reference surface 10 based on the change in the amount of reflected light at each point on the projection surface 12.

[0095] According to this aspect, the projection unit 30 can change the phase of the fringe pattern 36 simply by moving the mask 33. This reduces the time required to change the phase of the fringe pattern 36. This increases the number of times the amount of reflected light is measured at each point on the projection surface 12 per unit time. In this aspect, the measurement device 9 measures the height of each point on the surface of the object 11 based on changes in the amount of reflected light, making it possible to measure the shape of the object 11 with high accuracy.

[0096] (2) A second aspect of the measuring device 9 is the measuring device 9 of (1), in which the imaging unit 40 may continuously capture images of the fringe pattern 36 while the mask 33 is moving.

[0097] According to this aspect, the time required to measure the change in the amount of reflected light is reduced compared to, for example, the conventional case in which the projector controls the fringe pattern while changing the projection screen.

[0098] (3) The measurement device 9 of the third aspect is the measurement device 9 of (1) or (2), and the mask 33 may be inclined with respect to the optical axis O1 of the light source 32 so as to intersect with a plane perpendicular to the optical axis O1 of the light source 32.

[0099] For example, even if the optical axis O1 of the light source 32 is positioned at an angle relative to the normal to the measurement reference surface 10 in order to leave space above the measurement reference surface 10, the distortion of the fringe pattern 36 projected onto the projection surface 12 can be reduced by adjusting the angle of inclination of the mask 33 relative to the optical axis O1 of the light source 32.

[0100] (4) A fourth aspect of the measuring device 9 is a measuring device 9 of any one of (1) to (3), wherein the imager 44 has a plurality of pixels 45, each of which acquires the amount of reflected light at a point on the projection surface 12, and the information processing unit 50 further has a reflected light amount change table creation unit 58 that creates a reflected light amount change table that records changes in the amount of reflected light at a plurality of height positions on the measurement reference surface 10 for each pixel 45 when the object to be measured 11 is not placed on the measurement reference surface 10, and the height measurement unit 56 identifies, for a single measurement point on the surface of the object to be measured 11, a specific reflected light amount change that is closest to the change in reflected light amount acquired by the reflected light amount change measurement unit 54 based on the reflected light amount acquired at a single pixel 45 corresponding to the single measurement point, from the multiple reflected light amount changes recorded in the reflected light amount change table for the single pixel 45, and the height corresponding to the specific reflected light amount change may be the height of the single measurement point on the surface of the object to be measured 11.

[0101] The measuring device 9 of this embodiment can measure the height of the surface of the object 11 by simply comparing the change in the amount of reflected light in a reflected light amount change table acquired in advance with the change in the amount of reflected light on the surface of the object 11. As a result, even if the fringe pattern 36 is distorted, for example, the height of each point on the surface of the object 11 can be measured with high accuracy, regardless of the shape of the fringe pattern 36. Furthermore, even if the fringe pattern 36 is distorted due to non-uniformity in the amount of movement of the actuator 34, this embodiment makes it possible to measure the height of each point on the surface of the object 11 with high accuracy.

[0102] (5) A fifth aspect of the additive manufacturing apparatus 1 comprises a measuring device 9 selected from any one of (1) to (4), a stage 5 having a manufacturing surface 5a on which an object 2 is additively manufactured, a powder supply unit 6 that supplies powder 6a onto the manufacturing surface 5a, a coater 7 that flattens the powder 6a on the manufacturing surface 5a to form a powder bed 6b, and a head 8 that irradiates a beam 8a onto the powder bed 6b on the manufacturing surface 5a to sinter it, wherein the object 2 and the powder bed 6b are the object to be measured 11, the manufacturing surface 5a is the measurement reference surface 10, and the projection unit 30 further comprises a projection lens 35 arranged between the mask 33 and the measurement reference surface 10, and the mask 33 and the projection lens 35 are arranged parallel to the measurement reference surface 10.

[0103] According to this embodiment, even if the projection unit 30 is positioned at a position offset from directly above the forming surface 5a (measurement reference surface 10) and tilted relative to the measurement reference surface 10 in order to avoid the projection unit 30 interfering with the head 8, distortion of the fringe pattern 36 projected onto the measurement reference surface 10 is reduced.

[0104] (6) A sixth aspect of the additive manufacturing apparatus 1 is the additive manufacturing apparatus 1 of (5), wherein the imaging unit 40 further has a receiving lens 42 arranged between the imager 44 and the measurement reference surface 10, and the imager 44 and the receiving lens 42 may be arranged parallel to the measurement reference surface 10.

[0105] According to this embodiment, in order to avoid the imaging unit 40 interfering with the head 8, even if the imaging unit 40 is positioned at a position shifted from directly above the forming surface 5a (measurement reference surface 10) and tilted relative to the measurement reference surface 10, the imaging unit 40 can image the measurement reference surface 10 without distortion.

[0106] (7) The seventh aspect of the additive manufacturing apparatus 1 is the additive manufacturing apparatus 1 of (5), wherein the imaging unit 40 further has a light-receiving lens 42 arranged between the imager 44 and the measurement reference surface 10, and the imager 44, the light-receiving lens 42, and the measurement reference surface 10 are arranged along three reference lines L3 extending radially from a predetermined point, and the center 42a of the light-receiving lens 42 may be arranged on a straight line (optical axis O2) connecting the center 44b of the imager 44 and the center 10a of the measurement reference surface 10.

[0107] According to this aspect, it is possible to focus on the entire field of view of the imaging unit 40 without narrowing the iris of the imaging unit 40. This makes it possible to improve measurement accuracy.

[0108] According to the measuring device and additive manufacturing device of the present disclosure, it is possible to improve measurement accuracy.

[0109] REFERENCE SIGNS LIST 1 additive manufacturing device 2 object 3 chamber 3a housing 3b beam window 3c projection window 3d imaging window 4 cylinder 5 stage 5a manufacturing surface 6 powder supply unit 6a powder 6b powder bed 7 coater 8 head 8a beam 9 measurement device 10 measurement reference surface 11 object to be measured 12 projection surface 13 image 20 manufacturing control unit 21 stage control unit 22 powder supply control unit 23 coater control unit 24 head control unit 30 projection unit 32 light source 33 mask 33a substrate 33b stripe pattern 34 actuator 35 projection lens 36 fringe pattern 40 imaging unit 41 camera 42 light receiving lens 44 imager 44b center 45 pixel 45a corresponding pixel 50 Information processing unit 51 Projection control unit 52 Imaging control unit 53 Storage unit 54 Reflected light amount change measurement unit 55 Phase measurement unit 56 Height measurement unit 57 Surface shape measurement unit 58 Reflected light amount change table creation unit O1 Optical axis O2 Optical axis (straight line) P1 Measurement point P2 Measurement point PA Camera base point PB Projection base point L1 Base line L2 Camera line of sight L3 Placement reference line

Claims

1. A measuring device comprising: a measurement reference surface; a projection unit that projects a fringe pattern onto the surface of an object to be measured on the measurement reference surface; an imaging unit that images the fringe pattern projected onto the measurement reference surface and the surface of the object to be measured; and an information processing unit that processes information on the fringe pattern imaged by the imaging unit and measures the shape of the object to be measured. The projection unit includes: a light source that irradiates light toward the measurement reference surface; a mask that transmits the light irradiated from the light source and generates the fringe pattern; and an actuator that moves the mask. The projection unit changes the phase of the fringe pattern by moving the mask. The imaging unit includes an imager that acquires the amount of reflected light at each point on the projection surface where the fringe pattern is projected, among the measurement reference surface and the surface of the object to be measured. The information processing unit includes: a reflected light amount change measurement unit that measures the change in the amount of reflected light at each point on the projection surface accompanying the phase change of the fringe pattern, based on the amount of reflected light acquired a plurality of times with the phase of the fringe pattern changed at each point on the projection surface; and a height measurement unit that measures the height of each point on the surface of the object to be measured with respect to the measurement reference surface, based on the change in the amount of reflected light at each point on the projection surface.

2. The measuring device according to claim 1, wherein the imaging unit continuously images the fringe pattern while the mask is moving.

3. The measuring device according to claim 1 or 2, wherein the mask is inclined with respect to the optical axis of the light source so as to intersect a plane perpendicular to the optical axis of the light source.

4. The imager has a plurality of pixels each for acquiring the amount of reflected light of a point on the projection plane. The information processing unit further has a reflected light amount change table creation unit that creates a reflected light amount change table for recording the change in the amount of reflected light at a plurality of height positions of the measurement reference plane for each pixel in a state where the object to be measured is not disposed on the measurement reference plane. The height measurement unit specifies, for one measurement point on the surface of the object to be measured, the specific reflected light amount change that is closest to the reflected light amount change acquired by the reflected light amount change measurement unit based on the amount of reflected light acquired by one pixel corresponding to the one measurement point, from among the plurality of reflected light amount changes recorded in the reflected light amount change table for the one pixel, and sets the height corresponding to the specific reflected light amount change as the height of the one measurement point on the surface of the object to be measured. The measuring device according to claim 1 or 2.

5. The measuring device according to claim 1 or 2, a stage having a shaping surface on which a shaped object is laminated, a powder supply unit for supplying powder onto the shaping surface, a coater for flattening the powder on the shaping surface to form a powder bed, and a head for irradiating a beam onto the powder bed on the shaping surface to sinter it. The shaped object and the powder bed are the object to be measured, the shaping surface is the measurement reference plane, the projection unit further has a projection lens disposed between the mask and the measurement reference plane, and the mask and the projection lens are disposed parallel to the measurement reference plane. A laminated manufacturing apparatus.

6. The imaging unit further has a light receiving lens disposed between the imager and the measurement reference plane, and the imager and the light receiving lens are disposed parallel to the measurement reference plane. The laminated manufacturing apparatus according to claim 5.

7. The imaging unit further has a light receiving lens disposed between the imager and the measurement reference plane, the imager, the light receiving lens, and the measurement reference plane are disposed along respective ones of three arrangement reference lines radially extending from a predetermined point, and the center of the light receiving lens is disposed on a straight line connecting the center of the imager and the center of the measurement reference plane. The laminated manufacturing apparatus according to claim 5.

Images