JP2020026577A - Method for manufacturing three-dimensional molding and three-dimensional molding device - Google Patents

Abstract

To solve the problem that a powder laminate melting method occasionally generates a projection part when a three-dimensional molding is formed, and a detection technique which surely detects the projection part and does not damage a mechanism for flattening a powder layer has been desired.SOLUTION: A three-dimensional molding device includes a powder layer formation part for forming a powder layer in a predetermined region, an energy beam source which irradiates the powder layer formed by the powder layer formation part with an energy beam, melts or sinters the powder layer, and forms a solidification layer, and a contact detection sensor including a plate-like probe; and detects presence/absence of a projection on a surface of the solidification layer with the use of the contact detection sensor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a three-dimensional structure using a so-called powder lamination melting method, and a three-dimensional forming device used for the method.

In recent years, so-called 3D printers have been actively developed, and various methods have been tried. For example, various systems such as a hot melt lamination molding method, an optical molding method using a photocurable resin, a powder lamination melting method, and the like are known.
The powder lamination melting method includes a step of laying the raw material powder in layers and a step of sintering and solidifying by irradiating an energy beam such as a laser beam to selectively melt and solidify a part of the powder layer. This is a method of forming a three-dimensional structure by repeating the process. Nylon resin, ceramics, etc. are used for the raw material powder. In recent years, as a method for manufacturing articles requiring high mechanical strength and good thermal conductivity, a powder lamination melting method using a metal powder as a raw material has been used. It is starting to be used.
For example, Patent Document 1 proposes a manufacturing method in which a raw material powder such as a metal is spread in a layer using a squeezing blade, and then irradiated with laser light to manufacture a three-dimensional structure.

  Incidentally, when the powder layer is irradiated with an energy beam to be selectively melt-solidified or sintered-solidified, an unintended projection (projection-like solidified portion) may be formed. For example, a portion of the melted material may be scattered and adhere to the surface of a normally formed solidified layer, or a protrusion may be formed without the melt being melted into a lower layer already solidified. . Such an unintended projection may have a size of several tens of μm to about 300 μm and may protrude from the outermost layer.

  In recent years, in order to increase the shape accuracy and density of a three-dimensional structure, the thickness of each powder layer is set to about several tens of μm. The height of the projection may be larger than the upper surface of the powder layer. Then, the next time the powder layer is formed, the flattening mechanism for leveling the surface of the powder layer will mechanically interfere with the projection. In that case, the flattening mechanism is caught on the protrusion, and the step of forming the powder layer is stopped, the blade of the flattening mechanism is worn out by contact, or the shape accuracy of the three-dimensional structure is reduced. Will be. Furthermore, when the load increases due to friction and the flattening mechanism stops or the impact is large, the molded object may be broken.

  Patent Literature 2 describes a method of detecting the presence of a protrusion by a change in load of a driving motor of a flattening mechanism and a method of optically detecting the protrusion. Then, when the protrusion is detected, the powder layer is formed after removing the protrusion.

International Publication No. 2012/160811 JP-A-2004-277881

However, the method for detecting a protrusion disclosed in Patent Document 2 is not always a reliable method.
First, the method of detecting a protrusion by changing the load of the driving motor is a detection method on the premise that the flattening mechanism contacts the protrusion, so that the blade of the flattening mechanism may be worn by the contact. There is. The powder layer formed by the flawed blade has a swell corresponding to the flaw, and the portion causes insufficient melting of the powder layer, thereby reducing the shape accuracy of the three-dimensional structure.

In addition, the projection may take various shapes instead of a fixed shape, but the optical detection method using the imaging device described in Patent Document 2 may not be able to exhibit sufficient detection sensitivity depending on the shape of the projection. It is possible.
For this reason, there has been a demand for a detection technique capable of reliably detecting the protruding portion and not causing abrasion to the flattening mechanism.

  The present invention relates to a powder layer forming section for forming a powder layer in a predetermined region, and an energy beam source for irradiating the powder layer formed by the powder layer forming section with an energy beam to melt or sinter to form a solidified layer. And a contact detection sensor having a plate-shaped probe, wherein the presence or absence of a protrusion on the surface of the solidified layer is detected using the contact detection sensor.

  Further, the present invention provides a powder layer forming step of forming a powder layer of a predetermined thickness in a predetermined region using a powder layer forming unit and flattening the powder layer, and the powder layer flattened in the powder layer forming step. A solidifying step of irradiating an energy beam to form a solidified layer, and using a contact detection sensor provided with a plate-like probe, the powder layer forming portion is formed on the solidified layer formed in the solidifying step by the predetermined method. A step of detecting whether or not a projection having a height that interferes with the powder layer forming portion when forming a powder layer having a thickness is present in the solidified layer; and This is a method for manufacturing a molded article.

  ADVANTAGE OF THE INVENTION According to this invention, since the unintended projection part which generate | occur | produced by modeling can be detected reliably and the detection technique which does not give a wear to a flattening mechanism can be provided, the manufacture of a three-dimensional molded object with high shape precision is manufactured A method and a three-dimensional printing apparatus used for the method can be realized.

FIG. 2 is a front view of the three-dimensional printing apparatus according to the first embodiment as seen through the inside of the apparatus. (A) A perspective view of a projection detector provided with the plate-shaped probe of the first embodiment. (B) The figure explaining arrangement | positioning of the comb-shaped leaf spring. (C) Side view of the protrusion detector. (A) A perspective view of a projection detector provided with the plate-shaped probe of the second embodiment. (B) The figure explaining arrangement | positioning of a leaf spring pair. (C) Side view of the protrusion detector. (A)-(j) The figure which shows typically each stage in the middle after solidifying a part of powder layer until the next powder layer is laminated | stacked. FIG. 2 is a plan view of the three-dimensional printing apparatus according to the first embodiment. (A)-(h) The figure which shows typically the difference of the interference state by the difference in the relative position of a projection part detector and a projection part. FIG. 10 is a front view of the three-dimensional printing apparatus according to the third embodiment as seen through the inside of the apparatus. FIG. 10 is a plan view of the three-dimensional printing apparatus according to the third embodiment. FIG. 10 is a front view of the three-dimensional printing apparatus according to the fourth embodiment as seen through the inside of the apparatus. FIG. 13 is a front view of the three-dimensional printing apparatus according to the fifth embodiment as seen through the inside of the apparatus. (A)-(h) The figure which illustrates each process in Embodiment 2 typically. FIG. 4 is a diagram illustrating a difference in power density due to focusing of laser light.

[Embodiment 1]
Hereinafter, a method for manufacturing a three-dimensional structure and a three-dimensional structure apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front view schematically showing the inside of the three-dimensional printing apparatus to show the configuration of the three-dimensional printing apparatus according to the first embodiment.

In FIG. 1, reference numeral 1 denotes a galvano scanner for scanning a laser beam input from a laser light source (not shown) via, for example, a fiber, and 2 denotes a laser beam output from the galvano scanner at a predetermined height on a modeling stage. This is an f-θ lens for focusing light. Reference numeral 3 denotes a chamber for maintaining a space for forming a three-dimensional object in an inert gas-rich environment. Reference numeral 4 denotes a supply stage for supplying a powder material. Reference numeral 5 denotes a drive mechanism for the supply stage. Reference numeral 6 denotes a supply stage. Powder material. Reference numeral 7 denotes a molding stage serving as a base for supporting the molded object.
In order to form a model on the modeling stage 7, a powder material is spread on the modeling stage 7 so as to have a predetermined thickness, and a laser is irradiated at a predetermined position to melt and solidify the powder material. Thereafter, the position of the modeling stage 7 is lowered by a predetermined thickness, the powder material is spread again, and the laser irradiation is repeated to melt and solidify.

  Reference numeral 8 denotes a drive mechanism of the modeling stage. Reference numeral 9 denotes a recovery mechanism for recovering the remainder of the powder material transported from the supply stage to the molding stage. Reference numeral 10 denotes a roller as a flattening mechanism for leveling the surface of the powder material layer. The flattening mechanism 10 as a powder layer forming unit has a role of transporting the powder material of the supply stage to the modeling stage and a role of leveling the surface of the powder layer on the modeling stage. Reference numeral 11 denotes a positioning mechanism for controlling the height of the protrusion detector 12, which is mounted together with rollers on a carriage (not shown). When the carriage moves, the roller and the positioning mechanism 11 move integrally. Reference numeral 12 denotes a protrusion detector mounted on the positioning mechanism, and reference numeral 13 denotes a molded object obtained by melting and solidifying a powder material by laser irradiation. The protrusion detector 12 is disposed downstream of the flattening mechanism 10 as the powder layer forming unit in the moving direction of the carriage when forming the powder layer.

  As the protrusion detector 12, a method of mechanically bringing a plate-shaped probe into contact with a protrusion to detect the protrusion has high practical reliability, and specifically, a method using an elastic body such as a leaf spring. A detection sensor is preferably used.

  With reference to FIGS. 2A to 2C, as a first embodiment of the plate probe, a protrusion detector 12 using a plate spring group in which rectangular plate springs are connected in a comb-tooth shape will be described. I do. FIG. 2A is an external perspective view showing the configuration of the protrusion detector 12, FIG. 2B is an exploded view for explaining the positional relationship in the Y direction between two leaf spring groups, and FIG. FIG. 3 is a side view illustrating the configuration of the protrusion detector 12. In the present embodiment, a comb-tooth-shaped leaf spring group is used so that not only the presence or absence of the protrusion but also the position of the protrusion can be specified.

  14a and 14b are a group of leaf springs in which rectangular leaf springs are connected in a comb-teeth shape, and at positions where the phases are changed so as to interpolate the gap between the teeth in the Y direction as shown in FIG. 2 (b). It is piled up.

The leaf spring constituting each tooth of the comb tooth shape is made of a material having excellent spring properties such as phosphor bronze, and has a width in the Y direction of 5 mm and an aspect ratio (length in the Y direction: length in the Z direction) of 1 for example. : 4 to 1: 8. If the width in the Y direction is reduced, the resolution for detecting the position of the protrusion in the Y direction can be increased, but if it is too small, processing and handling are not easy. In addition, if the aspect ratio is increased, the teeth are easily deformed when they come into contact with the projections, so that the detection sensitivity can be increased. However, if the aspect ratio is too large, processing and handling are not easy. Therefore, the above-described shape is preferably used.
The comb teeth are arranged in the Y direction over a length of, for example, 300 mm so that the flattening mechanism 10 can cover the entire area of the powder layer formed in the predetermined area.

  A line sensor 16 is fixed at a position facing the leaf spring band 14 via a fixing member 15. The line sensor 16 is an optical sensor including a linear light source and a light receiving element group arranged in a line. When the leaf spring is not deformed, much of the light from the light source is reflected by the leaf spring and enters the light receiving element. However, when the leaf spring comes into contact with the protrusion and deforms, the reflection direction changes. The amount of light received by the light receiving element at the position facing the leaf spring changes greatly. This makes it possible to detect that the leaf spring has come into contact with the projection. By analyzing which light receiving element has changed the amount of received light, the position of the protrusion in the width direction of the leaf spring group can be detected.

Next, a projection detector 12 having a plurality of leaf spring pairs, which is a second embodiment of the plate probe, will be described with reference to FIGS. 3A to 3C.
FIG. 3A is an external perspective view showing the configuration of the protrusion detector 12, FIG. 3B is a cross-sectional view for explaining the positional relationship between the leaf spring pair in the Y direction, and FIG. FIG. 2 is a cross-sectional view illustrating a configuration of a detector 12.

  Reference numeral 17 denotes a pair of leaf springs in which a pair of leaf springs 17a and 17b of the same shape are arranged facing each other at a predetermined interval, and reference numeral 18 denotes a pair of leaf springs 18a and 18b of the same shape. It is a pair of leaf springs that are arranged at intervals.

  As shown in FIGS. 3A and 3B, the plurality of leaf spring pairs 17 are arranged in a predetermined direction (Y direction) at intervals equal to the width of the leaf spring. Similarly, the plurality of leaf spring pairs 18 are arranged along the Y direction at intervals equal to the width of the leaf spring. When viewed from the X direction, the leaf spring pair 17 and the leaf spring pair 18 are configured to be located between the opposing leaf spring pairs so as not to overlap with each other.

The fixing members 19 for fixing and supporting the leaf springs 17a, 17b, 18a and 18b are made of a non-conductive material. Wiring (not shown) is connected to each leaf spring, and a conduction sensor that detects electrical conduction between the leaf springs of each leaf spring pair is connected.
The leaf spring pairs are arranged in the Y direction over a length of, for example, 300 mm so that the flattening mechanism 10 can cover the entire region of the powder layer formed in the predetermined region.

When the leaf spring is not deformed, the leaf spring 17a and the leaf spring 17b are not in mechanical contact with each other, and thus are electrically insulated. The same applies to the leaf springs 18a and 18b. However, if the leaf spring comes into contact with the projection and is deformed during the movement of the projection detector 12, the leaf spring pair comes into contact with the pair of leaf springs and becomes electrically conductive. Therefore, the contact with the protrusion can be detected by the conduction sensor. By examining which leaf spring pair has generated electrical continuity, the position of the protrusion in the Y direction can be detected.
Here, setting of the height of the lower end of the leaf spring and detection of contact will be described in detail. If the lower end of the leaf spring and the tip of the projection are at the same height, the leaf spring and the projection can interfere with each other by moving the carriage in the X direction, even if the leaf spring can contact the projection. The leaf spring is not deformed. On the other hand, when the height of the protrusion is higher than the lower end of the leaf spring, the leaf spring is deformed by the movement of the carriage in the X direction according to the length of the interfering portion.

  Since the leaf spring pairs 17 and 18 have the same operation mechanism, here, the leaf spring pair 18 will be described with reference to FIGS. 6 (a) to 6 (h). In each of the drawings, reference numeral 13 denotes a molded object that has been solidified into a normal shape by laser irradiation, and reference numeral 200 denotes an abnormal projection formed along with the molded object 13. The leaf springs 18a and 18b are held by a fixing member 19. Here, as an example, a case will be described in which the length from the fixing member 19 to the tip of each leaf spring is 20 mm, and the distance between the leaf springs 18a and 18b is 0.5 mm. . The projection detector including these leaf springs is mounted on a carriage (not shown) and is moved in the X direction in the drawing.

  First, the case where the lower end of the leaf spring and the tip of the protrusion are at the same height will be described with reference to FIGS. 6 (a) to 6 (d). FIG. 6A shows a state in which the leaf spring 18a approaches the protrusion 200 formed on the modeled object 13 while the carriage is moving in the X direction. The dotted line is the lower end of the leaf springs 18a, 18b, and represents the height of the tip of the projection 200, and they match. Next, FIG. 6B shows a state in which the carriage slightly moves, and the leaf spring 18a comes directly above the protrusion 200. In FIG. 6B, the leaf spring 18a and the protrusion 200 are in contact with each other but do not interfere with each other, so that the leaf spring 18a is not deformed. When the carriage further moves in the X direction, as shown in FIGS. 6C and 6D, the leaf spring 18a moves away from the protruding portion 200 while being straight, and as a result, conduction by the leaf springs 18a and 18b does not appear.

  Next, a case where the projection and the leaf spring interfere with each other by 10 μm in height will be described with reference to FIGS. 6 (e) to 6 (h). FIG. 6E illustrates a state in which the leaf spring 18a approaches the protrusion 200 formed on the modeled object 13 while the carriage is moving in the X direction. The two dotted lines represent the heights of the lower ends of the leaf springs 18a and 18b and the tip of the projection 200, and the interval between the two is 10 μm. FIG. 6F shows a state in which the carriage is moved in the X direction from FIG. 6E and the leaf spring 18a comes directly above the protrusion 200. The leaf spring 18a interferes with the protruding portion 200 and causes bending. Further, when the carriage moves in the X direction, the leaf springs 18a and 18b come into contact as shown in FIG. When the carriage is further advanced in the X direction, the interference between the lower end of the leaf spring 18a and the projection 200 is released, the leaf spring 18a returns to the original straight state, and the contact between the leaf springs 18a and 18b disappears. Thereafter, although there is interference between the leaf spring 18b and the protrusion 200 in FIG. 6 (h), the leaf springs 18a and 18b do not contact each other.

When the leaf spring 18a this time is 20 mm and the length of the portion that interferes with the protrusion is 10 μm in the Z direction, when calculated by trigonometry, the amount of movement of the carriage in the X direction from the position in contact with the protrusion is 0. It interferes with the projection and deforms until it reaches about 63 mm. Since the distance between the leaf springs 18a and 18b is set at 0.5 mm, the leaf springs 18a and 18b come into contact with each other and can be detected.
Generally, the molding stage 7 and the flattening mechanism 10 (roller) are manufactured with extremely high rigidity in the Z direction in order to make the powder spread smooth and have a uniform thickness. There is a possibility. In other words, when the tip of the leaf spring of the roller and the projection detector is set to the same height, the projection (the lower end of the leaf spring and the tip of the projection that cannot be detected by the projection detector) have the same height. The projections) may damage the rollers during the spreading. In order to detect such a protrusion, it is necessary to set the tip of the leaf spring of the protrusion detector below the lower end of the roller.

  Next, of a series of modeling operations performed by the three-dimensional modeling apparatus of the present embodiment illustrated in FIG. 1, a powder layer forming operation will be described. 4 (a) to 4 (j) show that a part of the powder layer on the modeling stage 7 is irradiated with a laser beam to melt or sinter a part of the powder layer, and then the next powder layer is laminated. FIG. 7 is a diagram schematically showing each stage in the course of the operation. A modeling plate (not shown) may be provided on the modeling stage 7 and a powder layer may be formed thereon. In the present specification, a part of a powder layer that has been melted and then solidified or that has been baked and hardened (sintered) is referred to as a solidified layer. Further, in the present embodiment, an example in which the material is melted and solidified will be described as an example, but the same applies to a sintered material.

  First, FIG. 4A shows a state after a part of the powder layer on the modeling stage 7 is irradiated with laser light and the part of the powder layer is melted and solidified. From this state, by continuously forming the next powder layer and irradiating the layer with a laser beam, the solidified layer is superimposed to produce a model. FIG. 4A shows a state in which a projection is formed on a part of the modeled object 13 when the powder material is solidified by laser light irradiation.

  FIG. 4B shows a state in which the height of the modeling stage 7 has been reduced by one thickness t (arbitrary unit) as a stage prior to forming the next powder layer. Then, the carriage is moved to the molding stage side, and the height of the lower end of the leaf spring of the projection detector 12 is adjusted by the positioning mechanism 11 to be the measured height on the molding stage. The measurement height of the protrusion detector 12 is adjusted such that the lowermost end of the pair of leaf springs 18 of the protrusion detector 12 is, for example, 10 μm below the lowermost end of the roller of the flattening mechanism. By adjusting to this height, an unintended projection having a height that can interfere with the roller can be reliably detected. When the projection detector 12 shown in FIG. 3 is used, the presence or absence of an unintended projection is determined based on the presence or absence of electrical continuity between the pair of leaf springs 18. The leaf springs 18a and 18b are, for example, a pair of springs each having a width of 5 mm and an effective length of 20 mm. Therefore, in this case, the resolution of the protrusion detection position in the Y direction is 5 mm.

  Next, as shown in FIG. 4C, the presence / absence of a protrusion is determined while moving the protrusion detector 12 provided with the plate probe in the X direction. When the plate-shaped probe of the first aspect is used, if there is a projection, the comb-shaped leaf spring band is deformed by contact with the projection, and the deformation is detected by a line sensor to detect the projection. Judge that there is. Regarding the position of the protruding portion, the X coordinate is specified based on how far the carriage has been moved, that is, the scanning position of the plate probe, and the Y coordinate is specified based on which leaf spring (teeth) deformation has been detected.

  When a protrusion is detected, the height of the modeling stage 7 is further reduced by a certain amount (t) in order to grasp the height of the protrusion, and in that state, the protrusion detector 12 is again scanned in the X direction. Meanwhile, the presence or absence and location of the protrusion may be specified. If no protrusion is detected at the position where the protrusion was detected last time, the height of the protrusion is not less than t and less than 2 × t with respect to the surface of the powder layer at the time of the previous laser irradiation. It can be derived that there is. Further, if the projection is detected at the position where the projection was detected last time, the height of the modeling stage 7 is further reduced by a certain amount (t), and the scanning of the projection detector 12 is performed by the projection of the leaf spring pair 18. Repeat until there is no deformation detection due to contact with The height of the protrusion is derived between the integrated value of the amount of movement of the molding stage 7 in the Z direction until the detection of the deformation of the leaf spring pair 18 and the value obtained by subtracting a fixed amount (t) from the integrated value. .

In this example, the thickness t of one powder layer and the movement amount per molding stage for detecting the protrusion are made the same, but it is possible to operate with increasing or decreasing as appropriate.
Further, the roller and the protrusion detector serving as the flattening mechanism are mounted and operated on the same carriage, but may be mounted on separate carriages. In this case, since there is no need to move the roller when detecting the protrusion, there is an advantage that the risk of collision between the protrusion and the roller is eliminated. However, when mounted on separate carriages, controlling the height of the roller and the protrusion detector in the Z direction in the order of μm over the entire operation range is very costly for guides and the like. The position may change over time due to the rigidity of the parts. Therefore, it is advantageous to mount the flattening mechanism 10 and the protrusion detector 12 on the same carriage, since the relative positions of the roller and the protrusion detector can be easily controlled, and the apparatus configuration can be simplified.

When the protrusion is detected, as shown in FIG. 4D, the flattening mechanism 10 and the protrusion detector 12 are temporarily retracted, and the protrusion whose position is specified is removed. Alternatively, the powder layer is formed so that the surface of the powder layer is equal to or higher than the height of the protrusion. The removal of the projection is preferably performed by laser light irradiation, but a method in which a cutting tool is mounted on the apparatus and the cutting tool is used may be used.
FIG. 4E shows a state in which the protruding portion is melted by using a laser beam, and a portion having a height that can interfere with the roller of the flattening mechanism 10 is removed.

  After the irradiation of the laser beam, as shown in FIG. 4F, the projection detector 12 is set again, and the carriage is scanned to search for another projection. When another protrusion is detected, the operation of FIGS. 4C to 4F is performed to remove the protrusion having a height that can interfere with the roller.

Then, as shown in FIG. 4 (g), when the scanning can be performed without detecting the protrusion to the coordinates on the opposite side of the modeling stage, it is determined that there is no protrusion having a height that can interfere with the roller. Move on to the powder layer forming step.
When it is confirmed that there is no protrusion, as shown in FIG. 4H, the flattening mechanism 10 is returned to a position beyond the supply stage 4 by the carriage, and the supply stage 4 is raised by a certain amount to push up the powder material.

Thereafter, as shown in FIG. 4 (i), the flattening mechanism 10 is moved in the direction of the molding stage, and the powder material is moved to the molding stage 7. Further, as the rollers of the flattening mechanism 10 pass over the modeling stage, the conveyed powder material is stacked on the modeling stage.
Since the powder material is leveled by the rollers, the upper surface of the powder material transported to the molding stage is flattened as shown in FIG. 4 (j), and a powder layer having a flat upper surface is formed.

  Through the series of operations described above, the detection and removal of the protrusion and the formation of the powder layer are performed. In this embodiment, since the protrusion detector 12 shown in FIG. 2 or FIG. 3 is used, the position of the protrusion on the modeling stage can be detected, so that the removing operation can be performed efficiently.

With reference to FIG. 5, a method of obtaining the position of the protrusion on the modeling stage will be described in detail.
FIG. 5 is a plan view of the three-dimensional printing apparatus of the present embodiment as viewed from above. A flattening mechanism 10, a protrusion detector 12, a carriage 20 for scanning these, a supply stage 4, and a modeling stage 7 are shown. Further, 21 is a motor for rotating the rollers of the flattening mechanism 10, 22 is a driving means for the positioning mechanism 11 for adjusting the height of the projection detector 12, and 23 is a restraint on the movement of the carriage 20 in the Y and Z directions. It is a guide. Numeral 24 denotes a driving means for controlling the carriage in the X direction, which has a position control function. Reference numeral 25 denotes a projection formed on the modeling stage.

  As described with reference to FIG. 2 or FIG. 3, the protruding portion detector 12 has a plate-shaped probe having a predetermined width, that is, a plate spring, arranged along the Y direction. A required number of leaf springs are arranged so that the entire width of the modeling stage 7 in the Y direction can be inspected. The resolution in the Y direction when detecting an abnormality detection object is determined by the width of each leaf spring in the Y direction.

  When the carriage is driven in the X direction and the protrusion detector 12 reaches the end of the modeling stage 7, the height of the lower end of the leaf spring of the protrusion detector 12 is adjusted. That is, the height is adjusted so that the powder layer formed by the flattening mechanism 10 and the three-dimensional structure having a normal shape formed by melting and solidifying the powder layer do not come into contact with the protruding portion. Is done.

  Then, the carriage is driven, and the projection detector 12 scans the modeling stage. If the protrusion 25 is detected, the position in the X direction can be determined by the position of the carriage at the time of detection, and the position in the Y direction can be determined by the detection of the leaf spring.

  If it is found from the position detection resolution of the projection detector 12 that a projection exists in the area indicated by 27 in FIG. 5, the laser light or the cutting tool is operated in this area to efficiently operate the projection. Parts can be removed. When removing with a cutting tool, it is necessary to set the height in the Z direction. However, regarding the height of the cutting tool, What is necessary is just to be the same as height. When the protrusion detector 12 detects the protrusion, focusing only on the position in the X direction, the obtained X coordinate, that is, the line indicated by 26 in FIG. The removal operation may be performed by operating only the laser beam or the cutting tool.

Next, the removal of the protrusion using laser light will be described more specifically.
For example, the following description will be made on the assumption that a SUS316 having a center particle diameter of 20 μm is formed, and a protrusion having a height of 30 μm or more and less than 60 μm is detected at coordinates (X1, Y1).
Scanning irradiation is performed with a laser on the region including the protrusion. In the Y direction, the resolution is set to be about three times the range when the resolution is, for example, 5 mm, that is, 15 mm or less including both leaf springs. The X direction is set within a range of, for example, 3 mm or more and 15 mm or less, depending on the detection accuracy.
Then, the above-defined region is irradiated under a condition where the energy density is higher than the laser power at the time of forming the formed object (for example, laser power (60 W) under the forming condition when the powder thickness is 60 μm). The laser is irradiated at a scanning speed of, for example, 250 mm / s in the X direction and at a pitch of, for example, 50 μm in the Y direction.

Next, the protrusion detector is scanned to check whether the protrusion has been removed.
Here, in order to remove the protrusions, laser irradiation under conditions of high energy density is performed at a portion where the powder has already been melted and solidified. This is to ensure. In addition, the reason why the molten region is enlarged more than the region including the protrusion is to melt the surface of the protrusion that has already been melted and solidified to melt the protrusion. When only the projections are melted, the projections are melted and become spherical due to surface tension, and then often solidify and remain.

If the protrusion is still detected after the above laser irradiation, the shaping condition of the thicker powder layer (the condition with higher energy density) is appropriately changed in the same area or in the X direction until the protrusion is removed. Laser irradiation is performed on the enlarged area.
When the protrusion is detected, it is also possible to remove the protrusion by irradiating the laser to the entire region that has been melted and solidified by laser irradiation immediately before. However, laser scanning irradiation locally using the detected projection position as the center reduces the irradiation time, and also has advantages in both cost and function that the number of heated parts is small and distortion is suppressed. There is.
Further, when removing the protrusion, it is preferable to reduce the width of the leaf spring and increase the resolution in the Y direction in order to reduce the irradiation area. In addition, it is preferable to reduce the scanning speed when searching for a protrusion to increase the resolution in the X direction.

In addition, about the mechanical removal of a protrusion, the removal by cutting can also be applied. The removal by the laser can be performed by an energy beam such as a laser which is an essential requirement for the three-dimensional printing apparatus, but a mechanical removal requires a separate apparatus. In addition, although removal by an energy beam causes distortion due to heat history, there is no mechanical collision at the time of processing, so that it is particularly suitable for a material having poor ductility such as ceramics.
On the other hand, in mechanical removal, protrusions can be reliably removed along the trajectory of the tool, so there is no need to perform a process to confirm whether protrusions have been removed, as with the removal with an energy beam. This is advantageous in terms of reliability.
Even when mechanical removal by cutting or the like is performed, the position of the protrusion can be specified by the protrusion detector, so that there is an advantage that tool access and removal can be performed at high speed.

  As described above, the protrusion detector provided with the plate-like probe is provided, and the presence or absence of the protrusion is checked before the powder layer is formed. By using a plate-like probe, a protrusion can be detected with high reliability, and positional information of the protrusion can be obtained. When a protrusion is detected, the powder layer is formed after removing the protrusion, thereby avoiding contact between the flattening mechanism and the protrusion, preventing stop of the flattening and damage to the flattening mechanism, It is possible to stabilize the original molding work and improve the shape accuracy of the molded object.

[Embodiment 2]
In the first embodiment, the method of removing the protrusion when the protrusion is detected has been described. However, in the second embodiment, when the protrusion is detected, the surface of the powder layer to be spread next has the protrusion. A method of forming a sheet by spreading the powder so that the height is equal to or higher than the height will be described. Further, in the present embodiment, an example in which a powder material is melted and solidified will be described as an example, but the same applies to a sintered material.
When a protrusion having a height equal to or greater than the thickness of one powder layer is detected, in order for the flattening mechanism to be formed without colliding with the protrusion, the powder must be formed so that the surface of the powder layer is at least the height of the protrusion. It can be laid and shaped. A method for that will be described with reference to FIGS. 11 (a) to 11 (h).
11 (a) to 11 (h) are diagrams schematically showing each stage after a part of the powder layer is melted and solidified, and portions common to the first embodiment are denoted by the same reference numerals. Is shown.

First, laser irradiation conditions that enable high-quality modeling according to the thickness of the powder layer are determined in advance. The requirements for creating a shaped object are that the powder layer is melted and the already solidified part under the melting powder layer is melted to some extent and melted and solidified with the newly melted layer. is there.
Since the energy input to a certain irradiation position is proportional to the laser power and inversely proportional to the scanning speed, it is proportional to the energy density defined by laser power (W) / scanning speed (mm / sec). Therefore, by appropriately setting the power of the laser beam and the scanning speed, it is possible to control the melting and solidification including the powder layer and the already solidified portion under the powder layer.

  Further, in laser irradiation, the power density (irradiation power per unit area) differs depending on the position of the irradiation position in the beam diameter. Specifically, the center of the irradiation beam is strongest and generally maintained after passing through an f-θ lens according to a Gaussian distribution. As the power density increases, the temperature of the irradiating section increases according to the power density. However, if the power density is too high, the temperature of the irradiating portion rises due to the scanning speed of the apparatus and the limit of heat radiation due to heat conduction, and the volatilization and skipping of the material increase, so that high-quality modeling cannot be performed. Therefore, if the peak power density of the irradiation beam can be reduced without changing the power itself, the melting and solidification of a deeper surface or a larger area can be controlled without increasing the volatilization and skipping of the material. can do.

  One such technique is defocus. Defocusing refers to shifting the position of the powder layer in the Z direction (shifting to the defocus position) from the focus position where the irradiation beam diameter is most narrowed by the f-θ lens. An outline of defocus will be described with reference to FIG. The vertical axis represents the power density, the horizontal axis represents the spatial position, and the center of the beam diameter coincides with the position on the vertical axis. The solid line curve two-dimensionally represents the spatial distribution of the power density at the focus position where the beam diameter is most narrowed, and the power density at the time of defocusing with the dotted line. When defocused, the spatial region (horizontal axis) with power density is expanded, and the peak power density is reduced.

  In this state, the total amount of power is the same and the amount of heat applied is the same. Therefore, when material volatilization or powder jump occurs due to excessive peak power, shaping may be improved by defocusing. By lowering the peak power density at the same laser power by defocusing, or by using it together with increasing the laser power, it is possible to enlarge the melting region at the time of irradiation. Therefore, when the thickness of the powder layer is large, defocusing may be advantageous. However, defocusing also has a disadvantage that the fineness of modeling is deteriorated because the irradiation beam diameter increases.

  In consideration of these factors, laser irradiation conditions that enable high-quality modeling are determined in advance by experiments and the like. Basically, as the thickness increases, the amount of powder to be melted increases, so that the input energy per unit area and per unit time increases. In order to perform modeling, the already solidified portion immediately below the powder layer also needs to be melted. Therefore, the input energy required for modeling is not proportional to the thickness of the powder layer.

  Next, of a series of modeling operations performed by the three-dimensional modeling apparatus of the present embodiment, a powder layer forming operation will be described. 11 (a) to 11 (h) show the process of irradiating a part of the powder layer on the modeling stage 7 with a laser beam to melt and solidify a part of the powder layer, and then stacking the next powder layer. It is a figure which shows each stage in the middle typically. A modeling plate 109 may be provided on the modeling stage 7 and a powder layer may be formed thereon. In the present embodiment, an example in which a powder layer is formed on the modeling plate 109 will be described.

  First, FIG. 11A shows a state after a part of the powder layer on the modeling plate 109 is irradiated with laser light and the part of the powder layer is melted and solidified. From this state, by continuously forming the next powder layer and irradiating the layer with a laser beam, the solidified layer is superimposed to produce a model. FIG. 11A shows a state in which the projection 25 is formed along with the modeled object 13 when the powder material is solidified after being melted by laser light irradiation.

  FIG. 11B shows a state in which the height of the modeling stage 7 has been reduced by one thickness t (arbitrary unit) as a stage before forming the next powder layer. Then, the carriage is moved to the molding stage side, and the height of the lower end of the leaf spring of the projection detector 12 is adjusted by the positioning mechanism 11 to be the measured height on the molding stage. The measurement height of the protrusion detector 12 is adjusted such that the lowermost end of the pair of leaf springs 18 of the protrusion detector 12 is, for example, 10 μm below the lowermost end of the roller of the flattening mechanism. By adjusting to this height, an unintended projection having a height that can interfere with the roller can be reliably detected. When the projection detector 12 shown in FIG. 3 is used, the presence or absence of an unintended projection is determined based on the presence or absence of electrical continuity between the pair of leaf springs 18. The leaf springs 18a and 18b are, for example, a pair of springs each having a width of 5 mm and an effective length of 20 mm. Therefore, in this case, the resolution of the protrusion detection position in the Y direction is 5 mm.

  Next, as shown in FIG. 11C, the presence or absence of a protrusion is determined while moving the protrusion detector 12 provided with the plate probe in the X direction. When the plate-shaped probe of the first aspect is used, if there is a projection, the comb-shaped leaf spring band is deformed by contact with the projection, and the deformation is detected by a line sensor to detect the projection. Judge that there is. Regarding the position of the protruding portion, the X coordinate is specified based on how far the carriage has been moved, that is, the scanning position of the plate probe, and the Y coordinate is specified based on which leaf spring (teeth) deformation has been detected.

  When a protrusion is detected, as shown in FIG. 11D, the height of the molding stage 7 is further reduced by a certain amount (t) in order to grasp the height of the protrusion. The presence / absence and location of the protrusion may be specified while scanning the protrusion detector 12 in the X direction. If no protrusion is detected at the position where the protrusion was detected last time, the height of the protrusion is not less than t and less than 2 × t with respect to the surface of the powder layer at the time of the previous laser irradiation. It can be derived that there is. Further, if the projection is detected at the position where the projection was detected last time, the height of the modeling stage 7 is further reduced by a certain amount (t), and the scanning of the projection detector 12 is performed by the projection of the leaf spring pair 18. Repeat until there is no deformation detection due to contact with The height of the protrusion is derived between the integrated value of the amount of movement of the molding stage 7 in the Z direction until the deformation of the leaf spring pair 18 is no longer detected and a value obtained by subtracting a fixed amount (t) from the integrated value. .

In this example, the thickness of one layer of the powder layer and the movement amount per molding stage for detecting the protrusion are set to be the same, but the operation can be appropriately increased or decreased.
Further, the roller and the protrusion detector serving as the flattening mechanism are mounted and operated on the same carriage, but may be mounted on separate carriages. In this case, since there is no need to move the roller when detecting the protrusion, there is an advantage that the risk of collision between the protrusion and the roller is eliminated. However, when mounted on separate carriages, controlling the height of the roller and the protrusion detector in the Z direction in the order of μm over the entire operation range is very costly for guides and the like. The position may change over time due to the rigidity of the parts. Therefore, it is advantageous to mount the flattening mechanism 10 and the protrusion detector 12 on the same carriage, since the relative positions of the roller and the protrusion detector can be easily controlled, and the apparatus configuration can be simplified.

FIG. 11E shows a state where the protrusion is no longer detected. Next, as shown in FIG. 11 (f), the protrusion detector 12 is raised to a position where the powder spread is not hindered, and the flattening mechanism 10 (roller) is returned to a position beyond the supply stage 4 by the carriage, and the supply stage 4. Raise 4 to push up the powder material.
Thereafter, as shown in FIG. 11 (g), the flattening mechanism 10 (roller) is moved in the direction of the forming stage, and the powder material is moved to the forming plate 109. Further, as the flattening mechanism 10 (roller) passes over the modeling stage, the conveyed powder material is stacked on the modeling stage 7 and the modeled product 13 already formed. Since the powder material is leveled by the rollers, a powder layer is formed on the upper surface of the powder material conveyed to the molding stage, with the powder layer covering all the protrusions. The thickness of the powder layer at this time is the amount of movement of the modeling stage lowered until protrusions are no longer detected. For example, when the powder stage is lowered twice, the thickness becomes two layers (2 × t).
Thereafter, as shown in FIG. 11 (h), by irradiating the laser 121 under laser irradiation conditions suitable for the thickness of the powder layer determined in advance, it is possible to proceed with modeling without bumps hitting the rollers of the flattening mechanism. Can be.

(Example)
As an example, laser irradiation conditions when the thickness of the powder layer is changed will be specifically described.
In this example, Table 1 shows the results of experimentally determining the conditions under which the SUS316 powder having a center particle diameter of 20 μm can be formed by increasing the thickness of the powder layer every 30 μm. Modeling was possible up to a thickness of 150 μm of the powder layer, and modeling was impossible at 180 μm. In addition, it turned out that the conditions which can shape have a range with respect to each thickness. Those ranges are described in parentheses. Furthermore, it was found that the temperature was different because the way of heat dissipation was different depending on the shape of the model, the heat capacity of the model plate, and the distance from the model plate. Whether molding is possible or not is greatly affected by the temperature, and thus it is preferable to experimentally determine the value under each condition.

Table 1 shows parameters (SUS316, powder having a diameter of 20 μm) that enable high-quality modeling.

  As described above, by a series of steps described above, even when the conventional apparatus interferes with the powder spreading mechanism due to the occurrence of an unintended protrusion and causes a molding failure, a powder layer having an appropriate thickness equal to or larger than the protrusion is formed. By doing so, modeling can proceed.

[Embodiment 3]
Embodiment 3 A method for manufacturing a three-dimensional structure and a three-dimensional structure apparatus according to a third embodiment of the present invention will be described with reference to FIGS. 7 and 8. In the first embodiment, the flattening mechanism 10 and the protrusion detector 12 are integrated and mounted on the same carriage. However, in the third embodiment, they can be mounted on separate carriages and moved independently. It is configured to be.

  FIG. 7 is a front view schematically showing the inside of the three-dimensional printing apparatus in order to show the configuration of the three-dimensional printing apparatus of Embodiment 3, and FIG. 8 is a plan view of the three-dimensional printing apparatus as viewed from above. Portions common to the first embodiment are denoted by the same reference numerals.

  Two carriages 32 and a carriage 33 are arranged with respect to the guide 23, and a driving unit 34 and a driving unit 35 are arranged respectively. The flattening mechanism 10 and the positioning mechanism 36 are mounted on the carriage 32, and the protrusion detector 12 and the positioning mechanism 11 are mounted on the carriage 33. The structure is such that the flattening mechanism 10 and the protrusion detector 12 can scan on the modeling stage 7 independently. The present embodiment employing such a configuration has the following features as compared with the first embodiment shown in FIGS.

  In the first embodiment, since the flattening mechanism 10 and the protrusion detector 12 are mounted on one carriage 20, it can be constituted by a single carriage. However, after the first protrusion is detected by the protrusion detector 12, further scanning cannot be performed until the detected object is removed. This is because, if the scanning is continued without being removed, the first projection may come into contact with the flattening mechanism 10. Therefore, when the carriage is scanned and a protrusion is detected by the protrusion detector 12, first, the detected protrusion is removed, and then the presence or absence of the subsequent protrusion is searched. When a plurality of protrusions are formed on the modeling stage, such a procedure is repeated to detect and remove the entire area of the modeling stage, and thereafter, a process of forming a powder layer is performed.

  On the other hand, in the present embodiment, the protrusion detector 12 is mounted on a carriage different from the carriage of the flattening mechanism 10. Therefore, when the carriage 33 on which the projection detector 12 is mounted is scanned to detect the projection, its coordinates can be recorded and the subsequent scanning can be continued. For example, when the projections 37 and 38 exist on the modeling stage 7 as shown in FIG. 8, the projection detector 12 first scans the modeling stage 7 to detect the projections 37. When the coordinates are obtained, the projection detector 12 is continuously scanned without removing the projection 37, that is, without retracting the projection detector 12. Then, since the protrusion 38 is detected, the coordinates are obtained in the same manner. The scanning is continued without removing the protrusion 38, and it is confirmed that the scanning reaches the end of the modeling stage 7, and the scanning is terminated. In this manner, the entire area of the modeling stage is continuously scanned by the projection detector 12, and all coordinates of all the projections formed on the modeling stage 7 can be recorded. Therefore, even if a plurality of protrusions are generated, the detection operation is completed in a shorter time than in the first embodiment. Thereafter, a step of removing the detected protrusion may be performed.

  As described above, also in the present embodiment, the protrusion detector provided with the plate-shaped probe is provided, and the presence or absence of the protrusion is checked before the powder layer is formed. By using a plate-like probe, a protrusion can be detected with high reliability, and positional information of the protrusion can be obtained. When a protrusion is detected, the powder layer is formed after removing the protrusion, thereby avoiding contact between the flattening mechanism and the protrusion, preventing stop of the flattening and damage to the flattening mechanism, It is possible to stabilize the original molding work and improve the shape accuracy of the molded object.

[Embodiment 4]
Fourth Embodiment A method for manufacturing a three-dimensional structure and a three-dimensional structure apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 9 is a front view schematically showing the inside of the three-dimensional printing apparatus according to the fourth embodiment in order to show the configuration thereof, and portions common to the first embodiment are denoted by the same reference numerals. .

  In the three-dimensional printing apparatus according to the fourth embodiment, as in the first embodiment, a flattening mechanism 10, a protrusion detector, and a positioning mechanism 11 are mounted on one carriage. In the three-dimensional modeling apparatus according to the first embodiment, in FIG. 1, the supply stage 4 is provided only on the left side of the modeling stage 7, and the powder material can be transferred to the modeling stage 7 only from the left side. Therefore, after the powder layer is formed, it is necessary to return the carriage to the left side.

  On the other hand, in the three-dimensional printing apparatus according to the fourth embodiment, as shown in FIG. 9, the supply stage 4a, the driving mechanism 5a of the supply stage 4a, and the driving of the supply stage 4b and the supply stage 4b are provided on both sides of the modeling stage 7. The mechanism 5b was arranged. Thus, the powder layer can be formed by scanning the flattening mechanism 10 from either the left or right side of the modeling stage 7.

  Therefore, the projection detector 12a is installed on the left side of the flattening mechanism 10 and the projection detector 12b is installed on the right side of the positioning mechanism 11 so that the projection can be detected in either the left or right scanning direction. It is not always necessary to scan the shaping stage from one direction with the projection detector, and the scanning can be performed from the opposite direction every time a solidified layer is formed.

  When the carriage is on the left side of the modeling stage 7, the modeling stage 7 is lowered, the carriage is moved to the modeling stage 7, and the height of the protrusion detector 12b is adjusted by the positioning mechanism 11 at the end of the modeling stage 7. Thereafter, the protrusion detector 12b is scanned, and when a protrusion is detected, the carriage is retracted to remove the protrusion. Then, the height of the protrusion detector 12b is adjusted again at the end of the modeling stage 7, and scanning is performed again to detect the protrusion.

  When the scanning of the entire area on the modeling stage 7 is completed, the carriage returns to the left side, raises the supply stage 4a, and transports the powder material of the supply stage 4a onto the modeling stage 7 by the flattening mechanism 10 to form a powder layer. Then, the carriage is moved to the collection mechanism 9b on the right side. In this state, a laser beam is irradiated to selectively melt and solidify the powder layer on the modeling stage 7.

When the laser beam irradiation step is completed, the forming stage 7 is lowered to move the carriage on the right side to the forming stage 7 to form the next powder layer, and the protrusion is detected by the positioning mechanism 11 at the end of the forming stage 7. The height of the vessel 12a is adjusted. This time, the protrusion detector 12a is scanned toward the left side to search for and remove the protrusion. When the protrusion detector 12a reaches the end of the modeling stage 7, the carriage is returned to the right end, the supply stage 4b is raised, and the powder material is transported to the modeling stage 7 by the flattening mechanism 10, and a new powder layer is formed. Then, the carriage is moved to the left collecting mechanism 9a. In this state, laser light is selectively irradiated to form a solidified layer.
According to the configuration of the present embodiment, it is not necessary to return the carriage after the powder layer is formed by the flattening mechanism 10, and the time for forming the powder layer can be reduced.

  As described above, also in the present embodiment, the protrusion detector provided with the plate-shaped probe is provided, and the presence or absence of the protrusion is checked before the powder layer is formed. By using a plate-like probe, a protrusion can be detected with high reliability, and positional information of the protrusion can be obtained. When a protrusion is detected, the powder layer is formed after removing the protrusion, thereby avoiding contact between the flattening mechanism and the protrusion, preventing stop of the flattening and damage to the flattening mechanism, It is possible to stabilize the original molding work and improve the shape accuracy of the molded object.

[Embodiment 5]
Embodiment 3 A method for manufacturing a three-dimensional structure and a three-dimensional structure apparatus according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a front view schematically showing the inside of the three-dimensional printing apparatus according to the fifth embodiment in order to show the configuration of the three-dimensional printing apparatus. Portions common to the first embodiment are denoted by the same reference numerals. .

  The three-dimensional printing apparatus according to the fifth embodiment is characterized in that the flattening mechanism 10 and the protrusion detector, which are the features of the third embodiment, can scan the printing stage independently with a separate carriage. It has a configuration that allows both sides to be scanned. Thereby, the time required for forming the powder layer can be reduced compared to the configuration of the third embodiment.

  To this end, as shown in FIG. 10, a positioning mechanism 11a mounted on the carriage and a projection detector 12a are arranged on the left side of the flattening mechanism 10, and a positioning mechanism 11b mounted on the carriage and a projection detector on the right side. 12b is arranged.

  As shown in FIG. 10, when the flattening mechanism 10 is on the left side of the modeling stage 7, the protrusion detector 12b and the positioning mechanism 11b on the right side are moved to the modeling stage 7 by the carriage. The height of the protrusion detector 12b is adjusted by the positioning mechanism 11b, and the molding stage 7 is scanned leftward. When a protrusion is detected, scanning is completed up to the left end of the modeling stage while recording the detected coordinates on the modeling stage. Thereafter, the protrusion detector 12b and the positioning mechanism 11b are returned to the right by the carriage, and the removing operation is performed around the detected coordinates by using a laser beam or a cutting tool. Then, it is confirmed that the protrusion on the modeling stage 7 has been removed by using the protrusion detector 12b, the positioning mechanism 11b, and the carriage.

  When the removal is confirmed, the supply stage 4a is raised, the flattening mechanism 10 is scanned by the carriage, and the powder material of the supply stage 4a is transported onto the modeling stage 7 to form a powder layer on the modeling stage 7. At this time, if the supply stage 4b is lowered, excess powder material when the powder layer is formed on the modeling stage 7 can be collected on the supply stage 4b side, so that the powder material can be used effectively.

  The flattening mechanism 10 that has formed the powder layer on the modeling stage 7 does not return to the left position, but stops on the right collecting mechanism 9b. The powder layer formed on the modeling stage 7 is irradiated with a laser beam to produce a solidified layer. In order to form the next powder layer, after lowering the modeling stage 7, the projection detector 12a and the positioning mechanism 11a are moved, and the projection is detected by scanning the modeling stage 7 from left to right. If a protrusion is detected, a removal confirmation operation is performed after the removal operation. After confirming that there is no protrusion by the protrusion detector 12a and the positioning mechanism 11a, the powder material on the supply stage 4b is conveyed to the molding stage 7 by the flattening mechanism 10, and To form a new powder layer. At this time, if the supply stage 4a is lowered, the surplus powder material can be collected in the supply stage 4a, and the powder material can be used effectively.

  As described above, by adopting the configuration shown in FIG. 10, when the powder layer is formed, the return operation of the flattening mechanism 10 is not required, so that the time required for forming the powder layer can be reduced. Become.

  Further, according to the present embodiment, a protrusion detector provided with a plate-like probe is provided, and the presence or absence of the protrusion is checked before the powder layer is formed. By using a plate-like probe, a protrusion can be detected with high reliability, and positional information of the protrusion can be obtained. When a protrusion is detected, the powder layer is formed after removing the protrusion, thereby avoiding contact between the flattening mechanism and the protrusion, preventing stop of the flattening and damage to the flattening mechanism, It is possible to stabilize the original molding work and improve the shape accuracy of the molded object.

[Other embodiments]
Embodiments of the present invention are not limited to Embodiments 1 to 5 described above, but can be appropriately changed or combined, and many modifications are possible within the technical idea of the present invention. is there.

  For example, the flattening mechanism 10 is not limited to a roller, and other means capable of flattening the powder layer, such as a squeegee or a blade, may be used.

  The energy beam source for heating the powder layer is not necessarily a laser light source, but may be any light source that can irradiate a desired portion of the powder layer with sufficient heating energy.

DESCRIPTION OF SYMBOLS 1 ... Galvano scanner / 2 ... f-theta lens / 3 ... Chamber / 4, 4a, 4b ... Supply stage / 5, 5a, 5b ... Supply stage drive mechanism / 6 ...・ Powder material / 7 ・ ・ ・ Modeling stage / 8 ・ ・ ・ Model stage driving mechanism / 9, 9a, 9b ・ ・ ・ Recovery mechanism / 10 ・ ・ ・ Roller / 11, 11a, 11b ・ ・ ・ Positioning mechanism / 12 , 12a, 12b ... Projection detector / 13 ... Modeled object / 14a, 14b ... Leaf spring / 15 ... Fixed member / 16 ... Line sensor / 17, 18 ... Leaf spring Pair / 17a, 17b, 18a, 18b ... leaf spring / 19 ... fixing member / 20 ... carriage / 21 ... motor / 109 ... molding plate / 121 ... laser beam / 200 ··protrusion

Claims (19)

A powder layer forming section for forming a powder layer in a predetermined region,
An energy beam source for irradiating the powder layer formed by the powder layer forming unit with an energy beam and melting or sintering to form a solidified layer,
A contact detection sensor having a plate-like probe,
With
The presence or absence of a protrusion on the surface of the solidified layer is detected using the contact detection sensor,
A three-dimensional printing apparatus characterized by the following. The plate probe has a plate spring band in which a plurality of plate springs are arranged in a predetermined direction and connected in a comb shape,
The contact detection sensor includes an optical sensor that detects deformation of the plurality of leaf springs,
The three-dimensional modeling apparatus according to claim 1, wherein: Depending on which leaf spring of the plurality of leaf springs has been deformed, the position of the projection in the predetermined direction is detected.
The three-dimensional printing apparatus according to claim 2, wherein: The plate probe has a plurality of leaf spring pairs in which two leaf springs are arranged facing each other at a predetermined interval, and the contact detection sensor is configured to electrically connect the two leaf springs of each leaf spring pair. A continuity sensor that detects
The three-dimensional modeling apparatus according to claim 1, wherein: A plurality of the leaf spring pairs are arranged along a predetermined direction,
Depending on which of the pair of leaf springs is electrically connected, the position of the protrusion in the predetermined direction is detected.
The three-dimensional printing apparatus according to claim 4, wherein: The contact detection sensor is configured to scan the plate probe along a scanning direction,
By the scanning position of the plate probe when the plate probe detects the protrusion, the position of the protrusion in the scanning direction of the plate probe is detected,
The three-dimensional modeling apparatus according to any one of claims 1 to 5, wherein When the plate-shaped probe detects the protrusion, the powder layer forming unit forms a new powder layer thicker than the height of the protrusion on the solidified layer,
The three-dimensional modeling apparatus according to any one of claims 1 to 6, wherein: When the plate-shaped probe detects the protrusion, the powder layer forming unit forms a new powder layer on the solidified layer after removing the protrusion,
The three-dimensional modeling apparatus according to any one of claims 1 to 6, wherein: The powder layer forming section and the contact detection sensor are mounted on the same carriage,
The three-dimensional modeling apparatus according to any one of claims 1 to 8, wherein The contact detection sensor is disposed downstream of the powder layer forming unit in the moving direction of the carriage when forming the powder layer,
The three-dimensional printing apparatus according to claim 9, wherein: The powder layer forming section and the contact detection sensor are mounted on another carriage that can move independently.
The three-dimensional modeling apparatus according to any one of claims 1 to 8, wherein A powder layer forming step of forming a powder layer of a predetermined thickness in a predetermined region using the powder layer forming unit and flattening the powder layer,
A solidification step of irradiating the powder layer flattened in the powder layer formation step with an energy beam to form a solidified layer,
Using a contact detection sensor provided with a plate-shaped probe, when the powder layer forming section forms the powder layer of the predetermined thickness on the solidified layer formed in the solidifying step, the powder layer forming section And a detecting step of detecting whether or not a protrusion having a height that interferes with the solidified layer exists.
A method for producing a three-dimensional structure, comprising: The plate probe has a plate spring band in which a plurality of plate springs are arranged in a predetermined direction and connected in a comb shape,
The contact detection sensor includes an optical sensor that detects deformation of the plurality of leaf springs,
The method for producing a three-dimensional structure according to claim 12, wherein: The plate probe has a plurality of leaf spring pairs in which two leaf springs are arranged facing each other at a predetermined interval, and the contact detection sensor is configured to electrically connect the two leaf springs of each leaf spring pair. A continuity sensor that detects
The method for producing a three-dimensional structure according to claim 12, wherein: When the protrusion is detected in the detection step, a powder layer having a thickness greater than the predetermined thickness is formed in the predetermined region using the powder layer forming unit, and flattened.
The method for producing a three-dimensional structure according to any one of claims 12 to 14, wherein: When the protrusion is detected in the detection step, a removing step of removing the protrusion is performed, and thereafter, the powder layer having the predetermined thickness is formed in the predetermined region using the powder layer forming unit. And flatten,
The method for producing a three-dimensional structure according to any one of claims 12 to 14, wherein: Performing the detection of the protrusions in the entirety of the predetermined area in the detection step, performing the removal step after the detection step is completed,
The method for producing a three-dimensional structure according to claim 16, wherein: In the detecting step, the predetermined area is scanned by the contact detection sensor from one direction,
The method for manufacturing a three-dimensional structure according to any one of claims 12 to 17, wherein: In the detecting step, the predetermined area is scanned by the contact detection sensor from the opposite direction each time the solidified layer is formed,
The method for manufacturing a three-dimensional structure according to any one of claims 12 to 17, wherein:

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