JP6653590B2 - Cooling optimization device and cooling optimization method - Google Patents

Description

  The present invention relates to a cooling optimization device and a cooling optimization method.

  In recent years, in order to produce prototypes or products of various kinds in small quantities, a powder bed fusion bonding method in which solidified layers corresponding to the shape of a thin layer when the article is cut into slices are sequentially laminated to produce a shaped article of the article. Is attracting attention.

  In the powder bed fusion method, the temperature of the powder material is maintained at a temperature slightly lower than the melting point of the powder material by preheating, and the thin layer forming container is also maintained at a temperature slightly lower than the melting point of the powder material.

  Next, the surface of the powder material is leveled while the powder material is carried into the thin layer forming container by the transport member, and a thin layer of the powder material is formed on the elevating table.

  Next, the specific region is selectively heated based on the slice data by a laser beam, thereby sintering or melting and solidifying to form a bonding layer.

  Thereafter, the above operation is repeated while lowering the elevating table, and several hundred layers or thousands of layers are stacked to form a three-dimensional structure.

  After forming the model, the preliminary heating is stopped, and the model and the surrounding powder material are left in a thin layer forming container in a nitrogen atmosphere, and are cooled. In this cooling, since the heat capacity of the thin layer forming container, the modeled object, and the powder material around the container is large, it takes a very long time to cool.

  Then, after the temperature has been lowered to a level that can be handled by human hands, the modeled object is taken out of the thin layer forming container. Even though the surface temperature is low, the internal temperature of the shaped article taken out in this way has not yet fallen and is high, so that it is naturally cooled in the atmosphere.

JP 2004-306612 A JP 2006-312310 A

  As described above, the cooling in the powder-bed fusion bonding apparatus after the formation of the shaped article requires a very long time, and thus there is a problem that the apparatus cannot be operated for a long time.

  Also, even if the molded object is taken out early, warping occurs due to the temperature difference between the inside and the surroundings during resolidification, and the molded object is oxidized while performing natural cooling in the atmosphere. is there.

  The present invention has been made in view of the above-described problems, and provides a cooling optimization device and a cooling optimization method that can improve the operation rate while preventing warpage and oxidation of a modeled object. It is.

  In order to solve the above problems, according to one aspect, a container for cooling a thin layer forming container containing a formed object manufactured by powder bed fusion bonding, and a gas for the container for introducing an inert gas are provided. A cooling optimization device comprising: an inlet, a gas outlet of the container for discharging the inert gas, and gas flow rate adjusting means for adjusting a flow rate of the inert gas to be introduced into the container. Is provided.

  Further, according to another aspect, a step of selectively heating a powder material by powder bed fusion bonding in a thin layer forming container to produce a molded article, and the step of forming the thin layer in which the heated molded article is stored A step of accommodating the forming container in the container, introducing an inert gas into the container at a controlled flow rate, and cooling the shaped object heated by the inert gas while cooling the inert gas. Draining out of the container.

  According to the present invention, there is provided a container for accommodating and cooling a thin-layer forming container accommodating a shaped object produced by powder bed fusion bonding.

  Therefore, without having to wait until the temperature of the shaped object has dropped to near room temperature after completing the formation of the shaped object in the thin layer forming container, remove the thin layer forming container from the powder bed fusion bonding apparatus, store the container in the container, and cool. be able to.

  With this, while the shaped object is being cooled, another empty thin layer forming container can be attached to the powder bed fusion bonding apparatus, and the next powder bed fusion bonding can be performed. Can be improved.

  Further, the temperature of the object is reduced by forcibly removing heat of the object using an inert gas. In this case, by appropriately adjusting the flow rate of the inert gas to such an extent that the formed object does not warp, the cooling time can be reduced while preventing the formed object from warping or oxidizing.

(A) is a perspective view showing an external appearance of a container of the cooling optimization device according to the first embodiment of the present invention, and (b) is a gas flow regulator to a gas inlet of the container and a nitrogen gas generator. FIG. 3 is a diagram showing a connection relationship of FIG. It is the perspective view which saw through the inside of the container of the cooling optimization device concerning a 1st embodiment of the present invention. (A) is a top view which shows the powder bed fusion bonding apparatus which has the thin layer forming container which concerns on 1st Embodiment of this invention, (b) is a powder bed fusion bonding apparatus which follows the II line of (a). FIG. (A) is a perspective view showing the thin layer forming container according to the first embodiment of the present invention, and (b) is a bottom view showing the outside of the bottom of the thin layer forming container. (A)-(c) is sectional drawing (the 1) which shows the powder-bed fusion bonding method which concerns on 1st Embodiment of this invention. (A)-(c) is sectional drawing (the 2) which shows the powder-bed fusion bonding method which concerns on 1st Embodiment of this invention. (A)-(c) is a figure (the 1) which shows the cooling optimization method of the modeled object manufactured by the powder bed fusion bonding concerning a 1st embodiment of the present invention. (A)-(b) is a figure (the 2) which shows the cooling optimization method of the modeled object manufactured by the powder bed fusion bonding concerning a 1st embodiment of the present invention. (A)-(b) is the figure (the 3) which shows the cooling optimization method of the modeled object manufactured by the powder bed fusion bonding concerning a 1st embodiment of the present invention. (A)-(b) is a figure (the 1) which shows the method of preparing for the following powder bed fusion bonding during cooling of the modeled object shown in Drawing 9 (b). (A)-(c) is a figure (the 2) which shows the method of preparing for the following powder bed fusion bonding during cooling of the modeled object shown in Drawing 9 (b). (A)-(b) is a perspective view (the 1) explaining a pressing member which constitutes a cooling optimization device concerning a 2nd embodiment of the present invention, and a cooling optimization method. (A)-(b) is a perspective view (the 2) explaining the pressing member which comprises the cooling optimization apparatus which concerns on 2nd Embodiment of this invention, and the cooling optimization method. It is the perspective view which saw through the inside of the container of the cooling optimization device concerning a 3rd embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(1st Embodiment)
(1) Description of the cooling optimization device according to the first embodiment of the present invention As described above, after a shaped object having a desired shape is produced by powder bed fusion bonding, in order to remove the shaped object from the thin layer forming container. In addition, it is necessary to cool the shaped object in the thin layer forming container together with the powder material remaining around it.

  First, a cooling optimization device according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1A is a perspective view illustrating an appearance of a container of the cooling optimization device according to the first embodiment of the present invention.

  FIG. 1B is a diagram showing a connection relationship between a gas flow controller to a gas inlet of a container and a device for generating a nitrogen gas for cooling.

  FIG. 2 is a perspective view in which the door 1f of the container of FIG. 1A is removed and the inside of the container 1 is seen through.

  The cooling optimization device 101 has a cooling container (container) 1 having an external appearance as shown in FIG.

  The container 1 is a cubic space that becomes the storage chamber 2 that stores the thin layer forming container, or around a rectangular parallelepiped space, partition walls 1a to 1e that are open on one side only and are surrounded by a heat insulating member, And a door 1f having a heat insulating member as a main component, which can be opened and closed on one side.

  As shown in FIG. 2, a through hole (gas introduction port) 3a is formed in the partition wall 1a at the upper part of the storage chamber 2, and a nitrogen gas for cooling (an inert gas for cooling; A gas introduction pipe 4a for introducing nitrogen gas (also referred to as an inert gas) into the storage chamber 2 is provided. In addition, through holes (gas outlets) 3b and 3c are formed in the floor (lower partition wall or bottom of the container) 1b of the accommodation room 2 at the front left and the rear right, and the through holes 3b and 3c are formed in these holes. Exhaust pipes 4b and 4c for guiding the nitrogen gas introduced into the storage chamber 2 to the outside from the storage chamber 2 are respectively mounted.

  A gas flow controller (gas flow control means) 7 shown in FIG. 1B, for example, a needle valve, and a nitrogen gas temperature controller 8 are provided in the gas introduction pipe 4a for guiding the nitrogen gas into the storage chamber 2. A supply source 9 of an inert gas, for example, a nitrogen gas generator, is connected via the apparatus. The inert gas supply source 9 may alternatively use a cylinder into which argon gas is press-fitted.

  On the floor 1b surface of the accommodation room 2, two rows of guide rails 5 and 6 for guiding the thin layer forming container into the accommodation room 2 are attached in parallel at intervals.

  In each of the guide rails 5, 6, a pair of elongated rectangular members 5a / 5b, 6a / 6b are arranged in parallel with narrow gaps (recesses) 5c, 6c. A convex guide attached to the outer surface of the bottom of the thin layer forming container described later is fitted into the gaps 5c and 6c, so that the thin layer forming container can move along the guide rails 5 and 6. ing.

  Although not shown, the cooling optimization device includes a visual confirmation lamp for displaying whether the device is operating or stopped, a temperature detector for detecting the internal temperature of the object, and a temperature detector. A solenoid valve for automatically stopping the introduction of nitrogen gas when the temperature of the molded article falls to a predetermined temperature in response to a signal from the controller, and a timer for measuring time from the start of introduction of nitrogen gas.

  In addition, the temperature detector that detects the internal temperature of the modeled object is a device that is inserted in the vicinity of the modeled object 15c in the powder material in the thin layer forming container 12 housed in the container 1 and measures the temperature.

(2) Description of the powder bed fusion bonding apparatus according to the first embodiment of the present invention Next, regarding the powder bed fusion bonding apparatus according to the embodiment of the present invention, FIGS. 3 (a) and 3 (b) and FIG. ) And (b).

FIG. 3A is a top view showing a powder bed fusion bonding apparatus according to the first embodiment of the present invention,
FIG. 3B is a cross-sectional view of the powder bed fusion-bonding apparatus taken along the line II of FIG. 3A.

  FIG. 4A is a perspective view showing a thin layer forming container constituting the powder bed fusion bonding apparatus according to the first embodiment of the present invention, and FIG. 4B is an outer side of the bottom of the thin layer forming container. FIG.

  In the powder bed fusion bonding apparatus according to the present embodiment, as shown in FIGS. 3A and 3B, the energy beam emitting unit 102 and the thin layer 15a of the powder material are formed, and the energy beam 21 is melt-bonded by the energy beam 21. The apparatus includes a thin layer forming unit 103 that performs shaping, a recoater (transporting member) 10 that moves on the upper surface of the thin layer forming unit 103 and conveys a powder material, and a control unit (not shown) that controls the shaping. Resin, metal, ceramic, and the like can be used as the powder material.

  In the thin layer forming unit 103, as shown in FIGS. 3A and 3B, a base 11, a thin layer forming container 12 held on the base 11, and left and right sides of the thin layer forming container 12. And first and second powder material storage containers 13a and 13b held on the base 11.

  The base 11 is provided with first to third openings 14a to 14c from the left. The powder material is taken out of the first powder material storage container 13a through the first opening 14a, and the taken out powder material 15 is carried into the thin layer forming container 12 through the second opening 14b, and the powder material thin layer 15a is formed. Is formed, and the powder material 15 remaining after the formation of the thin layer is stored in the second powder material storage container 13b through the third opening 14c.

  The powder material 15 is taken out of the second powder material storage container 13b through the third opening 14c, and the powder material 15 remaining after forming the thin layer 15a is stored in the first powder material storage container 13a through the first opening 14a. In some cases.

  The thin layer forming container 12 and the first and second powder material storage containers 13a, 13b are provided with grooves 16a, 16b, 16c provided on left and right edges of the first to third openings 14a to 14c of the base 11. Then, the left and right upper edges of the containers 13a, 12 and 13b are inserted from the front of the base 11, and the containers 13a, 12 and 13b are mounted on the base 11. When removing the containers 13a, 12 and 13b from the base 11, the reverse is performed.

  The upper surface of the base 11 is flush with the entire thin layer forming portion 103. The recoater 10 such as a blade or a roller can move over the entire upper surface of the base 11.

  Further, as shown in FIG. 3B, inside the first and second powder material storage containers 13a, 13b and the thin layer forming container 12, the first portions serving as the bottoms of the containers 13a, 13b, 12 are respectively provided. In addition, the third lifting tables 18a, 18b, and 17 are provided. The first to third elevating tables 18a, 18b, 17 are connected to supporting shafts 20a, 20b, 19, respectively, which are connected to a driving device (not shown), so that they can move up and down.

4A and 4B show a detailed structure of the thin layer forming container 12. FIG. At the bottom of the container 12, a hole 12a through which the support shaft 19 passes is provided. The hole 12a is provided at the center of the bottom of the container 12 and smaller than the size of the third lift 17.
On the outer surface of the bottom of the thin layer forming container 12 on both left and right sides of the hole 12a, elongated rectangular members are arranged in parallel as the above-mentioned guides 23a and 23b with the hole 12a interposed therebetween.

  Further, rollers 24a / 24b and 24c / 24d are attached to the front and rear of the outer surface of the bottom of the container 12 outside the guides 23a and 23b, respectively. The rollers 24a / 24b, 24c / 24d are grounded on the installation floor when the thin layer forming container 12 is attached to and detached from the base 11, and are accommodated in the accommodation room 2 of the container 1 of the cooling optimization device. The floor 1b of the chamber 2 is grounded to facilitate movement of the thin layer forming container 12.

  As shown in FIGS. 3A and 3B, the recoater 10 reciprocates between the left and right first and second powder material storage containers 13a and 13b, so that the first and second powder material storage containers 13a and 13b. With respect to 13b, the supply side and storage side of the powder material 15 are switched every time one thin layer 15a is formed. In the first or second powder material storage container 13a or 13b on the supply side, the powder material 15 is placed on the first or second lift 18a or 18b and raised to supply the powder material 15. In the second or first powder material storage container 13b or 13a on the storage side, the second or first lifting table 18b or 18a is lowered, and the powder material 15 remaining after forming the thin layer 15a is removed from the second or first lifting table. Store on 18b or 18a.

  In the thin layer forming container 12, each time one bonding layer 15b is formed, the third lift 17 is lowered to sequentially stack new bonding layers 15b.

  Above the thin-layer forming container 12, irradiation means 102 for the energy beam 21 is arranged.

  As the energy beam 21, for example, an energy particle beam such as a laser beam or an electron beam can be used.

  Examples of usable laser light include a carbon dioxide laser, a YAG laser, an excimer laser, a He-Cd laser, and a semiconductor-excited solid laser.

 Further, in order to pre-heat the powder material 15 and its thin layer 15a, the thin layer forming container 12 is provided with a heater on the partition wall and the third elevating platform 17, and heaters 22a, 22b and infrared rays are also provided around the thin layer forming container 12. Lamps are located.

(3) Description of the powder bed fusion bonding method according to the first embodiment of the present invention Next, referring to FIGS. A method of performing the powder bed fusion bonding will be described.

  The control unit controls the movement of the recoater 10, the operation of each of the elevators 18a, 18b, and 17, and the operation of the powder bed fusion bonding apparatus such as the irradiation of the energy beam 21.

  In the thin layer forming step, the inside and the periphery of the thin layer forming container 12 and the first and second powder material storage containers 13a and 13b are preliminarily heated by heaters 22a and 22b and an infrared lamp shown in FIG. Good.

 Before the irradiation with the energy beam 21, the temperature of the thin layer 15 a of the powder material is kept at a temperature lower than the softening point of the powder material and 5 to 100 ° C. lower than the melting point by preheating, so that the energy beam 21 The fusion bonding can be easily performed. In this case, the temperature is more preferably 5 to 50 ° C lower than the melting point, and further preferably 5 to 30 ° C lower than the melting point.

  Next, as shown in FIG. 5B, first, the first lift 18a is raised, and the second and third lifts 18b, 17 are lowered.

  Next, as shown in FIGS. 5 (c) to 6 (a), the recoater 10 is moved to the right, and the powder material 15 is carried out from the first powder material storage container 13a by the recoater 10 to the thin layer forming container 12. Carry.

  Then, the recoater 10 is moved to the right, and the surface of the powder material 15 is leveled while the powder material 15 is carried on the third elevating table 17 in the thin layer forming container 12, thereby forming a thin layer 15a having a uniform thickness.

  By using a blade, a roller, or the like as the recoater 10, a thin layer 15a having a uniform thickness and a low porosity can be formed with good reproducibility.

  The thickness of the thin layer 15a of the powder material is preferably from 0.01 to 0.3 mm, and is preferably from 0.01 to 0.1 mm in order to obtain a more precise molded product.

  After forming the thin layer 15a, the recoater 10 is further moved to the right, and the remaining powder material 15 is stored in the second powder material storage container 13b.

  Next, in the bonding layer forming step, as shown in FIG. 6B, the thin layer 15a formed in the thin layer forming step is irradiated with the energy beam 21 based on the slice data of the shaping object, and the powder material is removed. By melting and bonding, a bonding layer 15b is formed.

  The atmosphere in which the thin layer 15a of the powder material is irradiated with the energy beam 21 is not particularly limited, but may be, for example, an inert gas atmosphere such as helium, argon, or nitrogen. The use of an inert gas atmosphere is preferable because oxidation and corrosion of the powder material 15 can be prevented. Further, the irradiation can be performed in the atmosphere.

  Subsequently, as shown in FIGS. 6 (c) to 7 (a), the powder bed fusion bonding device is operated according to FIGS. 5 (b) to 6 (b), and the recoater 10 is moved to the left. A second bonding layer 15b is formed.

  Thereafter, the above-described operation is sequentially repeated by the necessary number of layers of the bonding layer 15b to complete the modeled object 15c.

(4) Description of the method for optimizing the cooling of the shaped object 15c produced by the powder bed fusion bonding according to the first embodiment of the present invention (i) Removing the thin layer forming container from the thin layer forming section As described above, the shaping After the object 15c is completed, in order to cool the completed model 15c, in the present embodiment, the completed model 15c together with the thin layer forming container 12 is taken out from the thin layer forming unit 103.

  The method will be described with reference to FIGS. 7 (a) to 8 (b).

  Immediately after completing the modeled object 15c shown in FIG. 7A, the temperature of the modeled object 15c and the surrounding powder material is still at or near the melting temperature of the powdered material, and the modeled object still has fluidity. It is difficult to take it out immediately because there is strong heat.

  Therefore, immediately after completion of the shaped object 15c, it is attached to the powder bed fusion bonding apparatus for a while as it is, and the temperature of the shaped object 15c and the surrounding powder material is reduced to at least the temperature at which the powder material is completely solidified. Then, the modeling object 15c together with the thin layer forming container 12 is taken out as follows.

  That is, as shown in FIG. 7B, the lift 17 on which the completed model 15c and the surrounding powder material 15a are placed is lowered to the bottom of the thin layer forming container 12. Thereby, the hole 12a at the bottom of the thin-layer forming container 12 is closed.

  Next, as shown in FIG. 7C, the support shaft 19 is removed from the lift 17.

  Thereafter, as shown in FIG. 8A, the thin-layer forming container 12 mounted on the base 11 is pulled out to the front and removed from the base 11. At this time, as shown in FIG. 8 (b), in the thin layer forming container 12, the completed modeled object 15c and the powder material 15a remaining around it are stored.

(Ii) Storage of the thin-layer forming container in the container of the cooling optimization device As described above, after removing the thin-layer forming container 12 from the base 11, in this embodiment, the completed modeling together with the thin-layer forming container 12 The object 15c is stored in the cooling container (container) 1.

  The method will be described with reference to FIGS.

  In FIGS. 9A and 9B, the guide rails 5 and 6 provided on the floor 1b surface in the storage room 2 of the container 1 are shown by solid lines, and the inner wall surface (floor surface) of the storage room 2 of the container 1 is shown. ) Are indicated by dotted lines. Other parts of the container 1 are omitted.

  Open the door 1f of the container 1. Then, in order to house the thin layer forming container 12 in which the modeled object 15c is stored in the storage chamber 2 from the rear of the thin layer forming container 12, the guides 23a and 23b of the thin layer forming container 12 are guided by the guide rails 5 and 5 of the container 1. 6, the thin-layer forming container 12 is moved and pushed into the storage chamber 2 of the container 1.

  At this time, the thin layer forming container 1 is correctly guided into the storage chamber 2 by the guide rails 5 and 6 of the container 1, and the thin layer forming container 12 is controlled by the rollers 24a / 24b and 24c / 24d of the thin layer forming container 12. Is easier to move.

(Iii) Method for optimizing the cooling of the shaped object in the accommodation room of the container of the cooling optimization device Next, after the thin layer forming container 12 in which the object 15c is accommodated is accommodated in the accommodation room 2 of the container 1, A method of cooling the modeled object 15c together with the layer forming container 12 under an optimal environment will be described.

  A nitrogen gas for cooling (cooling inert gas; sometimes simply referred to as nitrogen gas (inert gas)) is introduced into the storage chamber 2 of the container 1 from the gas introduction port 3a through the gas introduction pipe 4a.

  At this time, the temperature of the nitrogen gas can be appropriately adjusted by the temperature controller 8 in a range from room temperature to the temperature of the modeled object 15c. For example, the temperature may be constant from the beginning to the end of the cooling, or may be constant at the temperature at which the molded object is taken out of the thin-layer forming container, or may be lowered over time according to the temperature of the molded object 15c that gradually decreases. May be changed. Thereby, generation of thermal strain can be further suppressed.

  The nitrogen gas introduced into the storage chamber 2 circulates around the storage chamber 2 and transfers the heat of the heated modeling object 15c from the gas outlets 3b, 3c to the outside of the storage chamber 2 through the exhaust pipes 4b, 4c. Carry it out. By continuing this, the temperature of the modeled object 15c can be reduced.

  At this time, if the flow rate of the nitrogen gas is increased, the cooling rate of the modeled object 15c is increased, but if it is too fast, the temperature difference between the modeled object 15c and its surroundings increases, which may cause thermal distortion and warpage. is there. For this reason, the flow rate of the nitrogen gas needs to be appropriately set so that the molded object 15c does not warp.

  When this state is maintained for a predetermined time, it can be handled by hand, and when the internal molded object 15c is completely re-solidified and cooled to a sufficiently cooled temperature, for example, about 50 ° C., the thin layer forming container 12 is taken out. .

  As described above, in the present cooling optimization method, the modeling is performed by forcibly removing the heat of the modeling object 15c together with the thin layer forming container 12 under the environment of the nitrogen gas at an appropriate flow rate such that the modeling object 15c does not warp. The temperature of the object is decreasing. This makes it possible to reduce the cooling time while preventing warpage or oxidation of the modeled object 15c.

(5) Description of the method for preparing for the next powder bed fusion bonding during cooling of the shaped article according to the first embodiment of the present invention (i) Mounting another thin layer forming container to the thin layer forming section As described above, the method of mounting another thin-layer forming container 12b to the thin-layer forming portion 103 after removing the thin-layer forming container 12 from the base 11 will be described with reference to FIGS. 10 (a) to 10 (b). It will be described with reference to FIG.

  Another empty thin layer forming container 12b shown in FIG. 10 (a) is prepared, and the thin layer forming container shown in FIG. 10 (b) is prepared in the reverse order to the order shown in FIG. 8 (a). Attach 12b to the base 11.

  At this time, an elevating table 17a is placed on the bottom surface of the thin-layer forming container 12b so as to close the bottom hole (12c in FIG. 11A).

(Ii) Preparation of Next Powder Bed Melt Bonding As described above, the method of preparing for the next powder bed melt bonding after mounting the empty thin layer forming container 12b on the base 11 will be described with reference to FIG. This will be described with reference to FIGS.

  As shown in FIG. 11A, a thin-layer forming container 12b having a lifting platform 17a placed on the bottom surface is mounted on the base 11. At this time, if the powder material 15 is not sufficiently left in the first and second powder material storage containers 13a and 13b, the powder material 15 is removed from the base 11, and the powder material 15 is added.

  Next, as shown in FIG. 11B, the support shaft 19 is attached to the back surface of the lift 17a through the hole 12c at the bottom of the thin layer forming container 12b.

  After that, as shown in FIG. 11C, the lift 17a is raised via the support shaft 19 so that the upper surface of the lift 17a is flush with the upper surface of the base 11. From this state, new modeling can be started as shown in FIG.

As described above, during the cooling of the modeled object 15c, another empty thin layer forming container 12b is mounted on the base 11, and the next powder bed fusion bonding can be performed. Operation rate can be improved (Second Embodiment)
Next, FIGS. 12 (a), (b), 13 (a), and 13 (b) show a cooling optimization device provided with a pressing member and a method of cooling a molded article according to a second embodiment of the present invention. It will be described with reference to FIG.

  FIGS. 12A, 12B, 13A, and 13B are perspective views illustrating the pressing member 25 and a method of cooling the modeled object 15c.

  In the cooling optimizing apparatus of this embodiment, as shown in FIG. 12A, a shaped object 15c in a thin layer forming container 12 housed in a container 1 and a powder material 15a remaining around the formed object 15c are pressed from above. The pressing member 25 is provided.

  The pressing member 25 is a plate-like member having a size substantially the same as or slightly smaller than the opening of the thin-layer forming container 12. The member may be made of, for example, stainless steel, and the weight may be appropriately used depending on the size of the thin-layer forming container, for example, 3 kg for a medium-sized container and 8 kg for a large-sized container. Note that the other reference numeral 25a is a handle for holding the pressing member 25 by hand.

  In the cooling method using this cooling optimizing device, as shown in FIG. 12A, a thin plate containing a molded object 15c immediately after fabrication and a powder material 15a remaining therearound is stored from a base of a powder bed fusion bonding device. After the layer forming container 12 is pulled out, a pressing member 25 to be placed on the shaped object 15c immediately after fabrication and the powder material 15a remaining around the shaped object 15c is prepared.

  Next, as shown in FIG. 12B, the pressing member 25 is placed on the shaped object 15c immediately after fabrication and the powder material 15a remaining around the shaped object 15c.

  Next, as shown in FIG. 13A, the thin layer forming container 12 is transported to a place where the cooling optimization device is installed.

  Next, as shown in FIG. 13B, the guides 23a and 23b at the bottom of the thin layer forming container 12 are fitted into the recesses 5c and 6c of the guide rails 5 and 6 provided on the floor 1b of the storage chamber 2 of the container 1. Then, the thin layer forming container 12 is pushed into the storage chamber 2 according to the guide rails 5 and 6. At this time, the temperature in the storage chamber 2 is substantially the temperature of the atmosphere, and therefore, the temperature difference from the modeled object 15c is large.

  Thereafter, after closing the door 1f, nitrogen gas whose flow rate is appropriately adjusted is introduced into the storage chamber 2 to lower the temperature of the modeled object 15c.

  At this time, the temperature difference between the thin layer forming container 12 and its surroundings is large, and warpage of the modeled object 15c is likely to occur due to thermal strain, but since the upper part of the modeled object 15c is pressed by the pressing member 25. In addition, it is possible to prevent the molded article 15c from warping due to the annealing effect. Accordingly, the flow rate of the cooling nitrogen gas can be set larger than in the first embodiment, or the temperature of the nitrogen gas can be set to room temperature.

  As described above, according to the second embodiment, even when the temperature difference between the modeled object 15c housed in the cooling device and its surroundings is large, or when the temperature of the nitrogen gas is set to room temperature, Even when the flow rate of the nitrogen gas for use is larger than that in the first embodiment, it is possible to prevent the occurrence of warpage of the modeled object 15c.

(Third embodiment)
Next, a cooling optimization device according to a third embodiment of the present invention will be described with reference to FIG.

  FIG. 14 is a perspective view of the inside of a cooling container (container) 1 of the cooling optimizing apparatus, as seen through.

  In this embodiment, a heating means for heating the inside of the storage chamber 2 of the container 1 is provided. This embodiment is optimal when it is not desired to use the pressing member 25 as in the second embodiment or when it is difficult to use it.

  As the heating means, for example, a heated inert gas for heating the inside of the storage chamber 2 is used. For example, nitrogen gas is used as the inert gas.

  As shown in FIG. 14, a gas inlet 26 is provided in the upper partition wall 1a of the container 1 in addition to the gas inlet 3a for nitrogen gas for cooling, and the nitrogen gas ( (Inert gas for heating). The other reference numeral 27 is a gas introduction pipe attached to the gas introduction port 26.

  Alternatively, without providing the gas inlet 26, the cooling nitrogen gas may be heated using the temperature controller 8 connected to the gas inlet 3a and used as the heating inert gas.

  An infrared light source or a resistance heater may be used as another heating means for heating the inside of the accommodation room 2 of the container 1.

  The infrared light source may be provided inside the accommodation room 2 or may be provided outside the container 1. In the latter case, the container 1 may be provided with an infrared transmission window, and the interior of the accommodation room 2 may be heated by irradiating infrared light from the window.

  The resistance heater may be provided in the accommodation room 2 or may be built in the partition wall.

  Next, a cooling optimization method using the container 1 provided with the heating means of FIG. 14 will be described.

  In this cooling optimization method, first, before storing the thin layer forming container storing the shaped object immediately after fabrication into the container 1, a nitrogen gas (heating means) heated from the gas inlet 26 in advance is stored in the storage chamber. The container 2 is introduced into the container 2, and the inside of the storage chamber 2 is heated to the same temperature as that of the model immediately after being taken out of the thin layer forming container.

  In this state, the thin-layer forming container is stored in the storage chamber 2.

  Next, after the temperature in the storage chamber 2 is stabilized, the heating by the heated nitrogen gas is stopped, and nitrogen gas for cooling is introduced into the storage chamber 2 from the gas inlet 3a.

  At this time, the temperature of the nitrogen gas for cooling can be appropriately adjusted by the temperature controller 8 in a range from room temperature to the temperature of the modeled object 15c. For example, the temperature may be constant from the beginning to the end of the cooling, or may be constant at the temperature at which the molded object is taken out of the thin-layer forming container, or may be lowered over time according to the temperature of the molded object 15c that gradually decreases. Change. Note that the flow rate of the nitrogen gas may be appropriately set to such an extent that the shaped article does not warp due to thermal strain.

  By maintaining this state for a predetermined period of time, the heat of the shaped object that has been heated by the nitrogen gas is sequentially carried out of the accommodation room 2 through the exhaust ports 3b and 3c, and the temperature of the shaped object is reduced at an appropriate temperature decreasing rate. Can be.

  As described above, in the present embodiment, the heating unit previously heats the inside of the storage chamber 2 to the same temperature as that of the shaped object immediately after production, and then places the thin layer forming container in the storage chamber 2. After housing, and then stopping the heating by the heating means, nitrogen gas is introduced into the housing chamber 2 to lower the temperature of the modeled object.

  Therefore, the temperature difference between the modeled object and its surroundings is small even immediately after the modeled object is stored in the storage chamber 2.

  Therefore, when nitrogen gas is introduced into the storage chamber 2 to lower the temperature of the object, the temperature of the object can be lowered while keeping the temperature difference between the object and its surroundings small.

  Thereby, generation | occurrence | production of a heat distortion can be suppressed more reliably in a molded object.

  Note that the present cooling method can be similarly performed even when an infrared light source or a resistance heater is used as the heating means.

  As described above, the present invention has been described in detail by the embodiment. However, the scope of the present invention is not limited to the example specifically shown in the above embodiment, and the scope of the present invention is not limited to the scope of the present invention. Modifications of the form are included in the scope of the present invention.

  For example, in FIG. 2, a gas inlet 3a is opened in an upper partition wall 1a of the accommodation room 2, and a gas outlet 3b is provided in the floor (lower partition wall) 1b of the accommodation room 2 in front left and back right. 3c, the inlet 3a is provided on the partition wall 1b, 1c on the side of the storage chamber 2, and the gas discharge port 3b, 3c is provided on the floor (lower partition wall) 1b of the gas storage chamber 2. It may be provided at the center.

  In FIG. 2, two rows of guide rails 5 and 6 for guiding the thin layer forming container 12 into the storage chamber 2 are provided on the floor 1b surface of the storage chamber 2; Another pair of guide rails may be provided inside the guide rails 5 and 6 so as to correspond to a thin layer forming container for small and medium-sized machines smaller than that.

  4A and 4B, the bottom of the thin layer forming container 12 is provided with a hole 12a through which the support shaft 19 passes, but the size and shape are not limited. The hole is provided to be smaller than the size of the third lift 17 and is large enough to allow the entire periphery of the third lift 17 to be placed on the bottom member of the thin layer forming container 12 around the hole. That's fine.

 In this case, the hole is relatively large, a heater plate having a large area capable of passing through the hole is placed on the support shaft 19, and the thin layer forming container 12 is further placed on the heater plate. it can. Thereby, the inside of the thin layer forming container 12 can be heated through a relatively wide portion at the bottom of the thin layer forming container 12.

  Finally, the inventions described in the above embodiments are summarized as additional notes below.

(Appendix 1)
A container for accommodating a thin-layer forming container in which a model formed by powder bed fusion bonding is stored, and a container for cooling,
A gas inlet of the container for introducing an inert gas,
A gas outlet of the container for discharging the inert gas,
Gas cooling means for adjusting the flow rate of the inert gas introduced into the container.

(Appendix 2)
2. The cooling optimization device according to claim 1, wherein, in addition to the shaped object, an unmelted powder material is stored around the shaped object in the thin layer forming container.

(Appendix 3)
The cooling optimization device according to claim 1, further comprising a pressing unit configured to press the formed object in the thin layer forming container.

(Appendix 4)
The cooling optimization device according to claim 1, wherein the gas flow rate adjusting means adjusts a flow rate of the inert gas introduced into the container according to a temperature of the modeled object.

(Appendix 5)
The cooling optimization device according to claim 1, wherein the gas flow rate adjusting means adjusts the flow rate of the inert gas introduced into the container to such an extent that the shaped object does not warp due to thermal strain.

(Appendix 6)
2. The cooling optimization device according to claim 1, further comprising heating means for raising the temperature in the container.

(Appendix 7)
The thin layer forming container has a convex or concave guide on the outside of the bottom portion, and the container has a concave or convex shape at the bottom portion that fits the guide and guides the thin layer forming container into the container. 2. The cooling optimization device according to claim 1, further comprising: a guide rail.

(Appendix 8)
2. The cooling optimization device according to claim 1, wherein the thin layer forming container includes a lifting platform, and the modeled object is placed on the lifting platform.

(Appendix 9)
The cooling apparatus according to claim 1, wherein the thin layer forming container has a preheating means for operating before the powder bed is melt-bonded to preheat the powder material placed on the elevator. Optimizer.

(Appendix 10)
2. The cooling optimization device according to claim 1, wherein the inert gas is a nitrogen gas, and further includes a nitrogen gas generation device.

(Appendix 11)
A step of selectively heating the powder material by powder bed fusion bonding in a thin layer forming container to produce a shaped article,
A step of accommodating the thin layer forming container in which the shaped object having the increased temperature is accommodated in a container,
A step of introducing an inert gas into the container at a controlled flow rate, and discharging the inert gas out of the container while cooling the shaped object heated by the inert gas. A cooling optimization method characterized by the following.

(Appendix 12)
The thin-layer forming container includes a lifting platform, and sequentially descends the lifting platform in the thin-layer forming container to form a thin layer of the powdered material on the lifting platform. 12. The cooling optimization method according to claim 11, wherein the bonding layer is formed by selectively heating the substrate to form a molded article including the multilayered bonding layer.

(Appendix 13)
13. The cooling optimization method according to claim 12, wherein, in addition to the shaped object, an unmelted powder material is stored around the shaped object in the thin layer forming container.

(Appendix 14)
12. The cooling optimization method according to claim 11, wherein the thin-layer forming container is accommodated in the container and cooled while the shaped object in the thin-layer forming container is pressed.

(Appendix 15)
12. The cooling optimization method according to claim 11, wherein the flow rate of the inert gas is adjusted to such an extent that the shaped object does not warp due to thermal strain.

(Appendix 16)
Before housing the thin-layer forming container in the container, a heating unit is operated to raise the temperature in the container, and after the thin-layer forming container is housed in the container, 12. The cooling optimization method according to claim 11, wherein the operation of the heating means is stopped before introducing the gas.

(Appendix 17)
12. The cooling optimization method according to claim 11, wherein the powder material is preheated before the powder material is selectively heated.

  1 ・ ・ ・ Cooling container (container), 1a-1e ・ ・ ・ Partition wall, 2 ・ ・ ・ Container room, 3a ・ ・ ・ Gas inlet, 3b, 3c ・ ・ ・ Gas outlet, 4a ・ ・ ・ Gas Inlet pipe, 4b, 4c ... exhaust pipe, 5, 6 ... guide rail, 5a, 5b, 6a, 6b ... elongated rectangular material, 5c, 6c ... gap (recess), 7 ... gas Flow rate controller (gas flow rate control means), 8: temperature controller, 9: supply source of cooling inert gas, 10: recoater (transportation member), 11: base, 12, 12b: thin layer forming container, 12a, 12c: hole, 13a: first powder material storage container, 13b: second powder material storage container, 14a: first opening, 14b. ..Second opening, 14c Third opening, 15 powder material, 15a thin layer (or thin layer) of powder material, 15b bonding layer, 15c shaped object, 16a-16c ... Groove, 17, 17a ... Third elevator, 18a ... First elevator, 18b ... Second elevator, 19, 20a, 2 0b: support shaft, 21: laser beam, 22a, 22b: heater, 23a, 23b: guide, 24a, 24b, 24c, 24d, 24g, 24h: roller, 25: pressing member , 25a: handle, 101: cooling device, 102: laser beam emitting portion, 103: thin layer forming portion.

Claims (10)

A container for accommodating a thin-layer forming container in which a model formed by powder bed fusion bonding is stored, and a container for cooling,
A gas inlet of the container for introducing an inert gas,
A gas outlet of the container for discharging the inert gas,
Gas flow rate adjusting means for adjusting the flow rate of the inert gas introduced into the container,
Pressing means for pressing the shaped object and the powder material remaining around the shaped object in the thin layer forming container,
A cooling optimization device characterized by having:   The cooling optimization device according to claim 1, wherein, in addition to the shaped object, an unmelted powder material is stored around the shaped object in the thin layer forming container.   The cooling optimization device according to claim 1, further comprising a heating unit configured to heat the inside of the container. The thin layer forming container has a convex or concave guide on the outside of the bottom,
The cooling optimization device according to claim 1, wherein the container has a concave or convex guide rail that fits into the guide and guides the thin layer forming container into the container at a bottom portion.   The cooling optimization device according to claim 1, wherein the thin-layer forming container includes a lifting platform, and the modeling object is placed on the lifting platform. A step of selectively heating the powder material by powder bed fusion bonding in a thin layer forming container to produce a shaped article,
A step of accommodating the thin layer forming container in which the shaped object having the increased temperature is accommodated in a container,
An inert gas into the container, introducing by adjusting the flow rate, while cooling the said shaped article according to the heating by the inert gas, the inert gas have a the step of discharging to the outside of the container ,
Cooling optimization , wherein the thin-layer forming container is accommodated in the container while the shaped object in the thin-layer forming container and the powder material remaining around the shaped object are pressed, and cooled. Method. The thin-layer forming container includes a lifting platform, and the lowering platform is sequentially lowered in the thin-layer forming container to form a thin layer of the powdered material on the lifting platform. 7. The cooling optimization method according to claim 6 , wherein the bonding layer is formed by selectively heating the substrate to form a shaped article including a plurality of the bonding layers. 7. The cooling optimization method according to claim 6 , wherein the flow rate of the inert gas is adjusted to such an extent that the shaped article does not warp due to thermal strain. Before accommodating the thin-layer forming container in the container, a heating unit is operated to raise the temperature in the container, and after the thin-layer forming container is accommodated in the container, the inert gas is removed. 7. The cooling optimization method according to claim 6 , wherein the operation of the heating unit is stopped before the introduction. 7. The cooling optimization method according to claim 6 , wherein the powder material is pre-heated before selectively heating the powder material.

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