JP2018030239A - Three-dimensional shaping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a three-dimensional shaping device capable of suppressing deposition of material powder to discharge heads.SOLUTION: The three-dimensional shaping device proposed herein comprises a shaping table, a plurality of discharge heads, a moving mechanism, a movement control part and a discharge control part. At least a discharge head that discharges a hardening liquid for hardening material powder is included in the plurality of discharge heads. The moving mechanism includes a holding part that holds the plurality of discharge heads, and the movement control part controls the moving mechanism so as to feed the discharge heads defined in advance among the plurality of discharge heads in order to a shaping position defined in advance on the shaping table. The discharge control part sets a discharge condition of the first discharge head discharging to the shaping position first, out of the discharge heads to be fed to the shaping position in order, to a discharge condition with which the material powder is not easily scattered than a discharge condition of the second discharge head discharging second.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a three-dimensional modeling apparatus.

  In a 3D modeling apparatus that forms a 3D model by discharging a curing liquid or the like to a material powder and curing it, the material powder is scattered by the discharge of the liquid, and the material powder adheres to the discharge head that discharges the liquid. Occur. When the material powder adheres to the discharge head, the liquid is not normally discharged from the discharge port, which may affect the quality of the object to be modeled. Patent Document 1 discloses a three-dimensional modeling apparatus characterized by how to move an ejection head that is less likely to impair the quality of an object to be modeled even if an ejection head that has suffered an ejection failure appears.

JP2011-212862

  An object of the present invention is to suppress adhesion of material powder to a discharge head in a three-dimensional modeling apparatus that forms a three-dimensional model by discharging a curing liquid or the like to a material powder and curing it.

  The proposed 3D modeling apparatus includes a modeling table, a plurality of ejection heads, a movement mechanism, a movement control unit, and a ejection control unit. Material powder is placed on the modeling table. Among the plurality of discharge heads, at least a discharge head that discharges a curable liquid that hardens the material powder is included. The moving mechanism includes a holding unit that holds a plurality of ejection heads, and moves the plurality of ejection heads with respect to the modeling table. The movement control unit controls the movement mechanism so as to sequentially send a predetermined ejection head among the plurality of ejection heads to a predetermined modeling position on the modeling table. The discharge control unit is configured such that, out of the discharge heads that are sequentially sent to the modeling position, the discharge condition of the first discharge head that discharges first to the modeling position is set to be higher than the discharge condition of the discharge head that discharges second to the modeling position. The discharge conditions are set so that the material powder placed on the table is less likely to be scattered.

  In the above-described three-dimensional modeling apparatus, first, the first discharge head wets the material powder at the modeling position so that the material powder is hardly scattered. Thereby, scattering of the material powder is suppressed when the discharge heads after the second discharge head discharge, and adhesion of the material powder to the discharge heads after the second discharge head is suppressed. Further, since it is less necessary to consider the scattering of the material powder when discharging the discharge heads after the second discharge head, the productivity is hardly affected. Since the discharge conditions of the first discharge head are set to discharge conditions that make it difficult for the material powder to scatter, adhesion of the material powder to the first discharge head can also be suppressed.

It is sectional drawing which represented typically the three-dimensional modeling apparatus in one Embodiment. It is the top view which looked at the three-dimensional modeling apparatus of FIG. 1 from upper direction. It is the schematic diagram which looked at the holding | maintenance part periphery from the front. 6 is a flowchart of processing performed by the ejection control unit during one scan in the main scanning direction in an embodiment. It is the top view which represented typically the modeling table top at the time of the precoat start of a 1st discharge head. It is the top view which represented typically the modeling table at the time of the discharge start of a 2nd discharge head. It is the top view which represented typically the modeling table at the time of the completion | finish of the precoat of a 1st discharge head. It is the top view which represented typically the modeling table at the time of completion | finish of discharge of a 6th discharge head. FIG. 5 is a plan view schematically showing a modeling table on the first scanning in the embodiment in which the first ejection head is arranged in front of the sub-scanning direction. FIG. 10 is a plan view schematically showing a modeling table on the second scanning in the embodiment in which the first ejection head is arranged in front of the sub-scanning direction. It is an arrangement example of the ejection head in the case of bidirectional modeling. It is an example of arrangement of an ejection head different from FIG. 11 in the case of bidirectional modeling.

  Hereinafter, embodiments of the present invention will be described. The embodiments described herein are, of course, not intended to limit the present invention. Further, members / parts having the same action are denoted by the same reference numerals, and redundant description is omitted or simplified.

  FIG. 1 is a cross-sectional view schematically showing a three-dimensional modeling apparatus 10 according to an embodiment. Here, the left side of FIG. 1 is the left side L of the 3D modeling apparatus 10, the right side of FIG. 1 is the right side R of the 3D modeling apparatus 10, the upper side of FIG. 1 is the upper side U of the apparatus, and the lower side of FIG. Let D be the lower part of the apparatus. FIG. 2 is a plan view of the three-dimensional modeling apparatus 10 of FIG. 1 as viewed from above. 1 is a cross-sectional view taken along the line II in FIG. Therefore, the left side of FIG. 2 is the left side L of the 3D modeling apparatus 10, the right side of FIG. 2 is the right side R of the 3D modeling apparatus 10, the lower side of FIG. 2 is the front F of the apparatus, and the upper side of FIG. It is the rear Rr of the original modeling apparatus. Hereinafter, in the description of the embodiment, when the direction is described, the above direction is meant. However, these are only directions for convenience of explanation, and do not limit the installation mode of the three-dimensional modeling apparatus 10.

  As shown in FIGS. 1 and 2, according to the present embodiment, the three-dimensional modeling apparatus 10 includes ejection heads 20 a to 20 f, tanks 30 a to 30 f, a modeling table 40, a modeling tank 42, and a first lifting / lowering. The mechanism 44, the material tank 46, the 2nd raising / lowering mechanism 48, the roller 50, the moving mechanism 52, the movement control part 70, and the discharge control part 72 are provided.

  The ejection head is a mechanism that ejects liquid onto the material powder 100. There are a plurality of discharge heads, at least one of which is a discharge head that discharges a curable liquid that hardens the material powder 100. In the embodiment shown in FIGS. 1 and 2, there are six ejection heads 20a to 20f, which are held in a line along the left-right direction by a holding portion 52a. The discharge heads 20a to 20f are connected to the tanks 30a to 30f, respectively, and discharge the discharge liquid stored in the tanks connected thereto. According to the example shown in FIG. 2, the discharge head 20a uses a precoat liquid 110P, which will be described later, the discharge head 20b uses a cyan color liquid 110C, the discharge head 20c uses a magenta color liquid 110M, and the discharge head 20d uses a yellow color liquid 110Y. The discharge head 20e is connected to the tank so as to discharge the black color liquid 110K, and the discharge head 20f discharges the curable liquid 110B. In this example, the selection and arrangement of the discharge liquids in the discharge heads 20a to 20f are as described above. Of course, this is an example. The ejection heads 20a to 20f are controlled to perform ejection when scanned in the Y1 direction. The Y1 direction coincides with the left L of the three-dimensional modeling apparatus 10. For example, a piezo drive system is adopted as the drive system of the ejection head. A piezo drive type discharge head includes a pressure chamber filled with a liquid to be discharged. A fine nozzle hole is formed in the pressure chamber. A piezoelectric element (piezo element) is in contact with the outer wall of the pressure chamber. When a voltage is applied to the piezo element, the variation of the piezo element due to the voltage application is transmitted to the pressure chamber. As a result, the volume of the pressure chamber is reduced, and the reduced volume is ejected as droplets. The nozzle holes are arranged side by side in the X direction on the ejection surface of the ejection head. The X direction is a direction orthogonal to the Y direction and coincides with the front-rear direction of the three-dimensional modeling apparatus 10. The density of the nozzle holes determines the density of the droplets in the X direction. The density of droplets is usually expressed in dots per inch (dpi). For example, if 200 nozzle holes are arranged side by side in the X direction, the dot density in the X direction is 200 dpi. The discharge heads 20 a to 20 f are held with the discharge surface facing downward D so that the liquid can be discharged toward the material powder 100 on the modeling table 40.

  A material powder 100 is placed on the modeling table 40. The modeling table 40 is a member on which modeling is performed, and each time modeling proceeds, a new layer is stacked on the part of the modeling target 200 that has been modeled so far. Therefore, on the modeling table 40, a part of the modeling target 200 that has been modeled so far is placed. The modeling table 40 is installed inside the modeling tank 42 and can slide up and down. The modeling table 40 is connected to the first lifting mechanism 44 from below in the modeling tank 42. The first lifting mechanism 44 can move the modeling table 40 up and down in the modeling tank 42.

  In this embodiment, the material tank 46 is next to the modeling table 40 and stores the material powder 100. The material tank 46 is one of mechanisms for supplying the material powder 100 onto the modeling table 40. The bottom 46 a of the material tank 46 can slide up and down in the material tank 46. A second lifting mechanism 48 is connected to the lower surface of the bottom 46a. The second elevating mechanism 48 can move the bottom 46 a up and down in the material tank 46. The material powder 100 stored in the material tank 46 is, for example, gypsum, ceramics, metal, plastic, or the like.

  The three-dimensional modeling apparatus 10 according to this embodiment includes a roller 50. As shown in FIG. 1, the roller 50 is installed such that the lower surface is at the same height as the uppermost surface of deposition on the modeling table 40 (hereinafter referred to as a modeling surface Ly). As shown in FIG. 2, the length of the roller 50 in the front-rear direction is longer than the width of the modeling tank 42 and the material tank 46 in the front-rear direction. The roller 50 is horizontally moved in the left-right direction by a drive unit (not shown).

  The moving mechanism 52 is a mechanism that holds the discharge heads 20 a to 20 f and moves the modeling table 40. The moving mechanism 52 includes a holding unit 52a that holds the ejection heads 20a to 20f. A predetermined interval of, for example, about 2 mm is provided between the ejection surfaces of the ejection heads 20a to 20f held by the holding unit 52a and the modeling surface Ly on the modeling table 40. According to the embodiment shown in FIGS. 1 and 2, the moving mechanism 52 moves the ejection heads 20 a to 20 f in the Y direction and the X direction. The Y1 direction is determined to coincide with the left L of the three-dimensional modeling apparatus 10, and is the main scanning direction in which the ejection heads 20a to 20f are scanned while ejecting. Further, the direction in which the ejection heads 20a to 20f are scanned between the ejection and the ejection intersecting with the Y direction is the sub-scanning direction X1. In the present embodiment, the sub-scanning direction X1 is orthogonal to the main scanning direction Y1 and coincides with the front F of the three-dimensional modeling apparatus 10. In this example, the X direction and the Y direction are orthogonal, but this intersection is not limited to orthogonal. The moving mechanism 52 includes a main scanning unit 52y that moves the ejection heads 20a to 20f in the Y direction and a sub-scanning unit 52x that moves the ejection heads 20a to 20f in the X direction. The main scanning unit 52y is connected to the holding unit 52a and moves the holding unit 52a in the Y direction along the main scanning unit guide rail 52yg. The sub-scanning unit 52x is connected to the main scanning unit 52y and moves the main scanning unit 52y in the X direction along the sub-scanning unit guide rail 52xg. In the embodiment shown here, the modeling table 40 is stationary, and the ejection heads 20a to 20f are moved by the moving mechanism 52. However, this movement may be relative, and the modeling table 40 is It may be moved in either the Y direction or the X direction, or both. In the embodiment shown here, the moving mechanism 52 moves the ejection heads 20a to 20f in both the Y direction and the X direction, but may move only in the Y direction. In that case, the holding part 52a usually takes a so-called line head type structure in which a large number of ejection heads are arranged so as to cover the entire width of the modeling region in the X direction.

  The movement control unit 70 controls the movement mechanism 52 so that the ejection heads 20a to 20f are sequentially sent to a modeling position predetermined on the modeling table 40. Further, the movement control unit 70 controls the movement mechanism 52 so as to move the ejection heads 20a to 20f at a predetermined scanning speed. The movement control unit 70 controls the main scanning unit 52y in the Y-direction scanning, and controls the sub-scanning unit 52x in the X-direction scanning.

  The discharge controller 72 controls the discharge heads 20a to 20f. The ejection control unit 72 causes the ejection heads 20a to 20f to eject liquid at a predetermined timing when the ejection heads 20a to 20f are scanned in the main scanning direction Y1. The discharge timing is based on information such as drawing data of the object 200. It is desirable that the discharge conditions can be set individually for each discharge head.

  The movement control unit 70 and the discharge control unit 72 are not limited to a single device (for example, a unit incorporated in the main body of the three-dimensional modeling apparatus 10). For example, some or all of the functions may be performed by an external computer or the like connected to the main body. An external computer or the like includes an interface (I / F) for transmitting and receiving data and the like, a central processing unit (CPU), a ROM for storing a calculation program executed by the CPU, and a RAM used as a working area for developing the program And a storage device for storing various data.

  The three-dimensional modeling apparatus 10 models the object 200 by the following process. That is, the three-dimensional modeling apparatus 10 models the workpiece 200 by laminating layers having a predetermined thickness of about 0.1 mm, for example, one after another. The shape of the layer formed at a certain height in the vertical direction is the cross-sectional shape of the object 200 at that height. When one layer of modeling is completed, the modeling table 40 is moved downward D in the modeling tank 42 by the first lifting mechanism 44. The amount of movement at this time is the thickness of one layer at the time of modeling. Next, the bottom 46 a of the material tank 46 is moved upward U in the material tank 46 by the second lifting mechanism 48. Therefore, a part of the material powder 100 in the material tank 46 is raised and stacked above the upper end of the material tank 46 (the same surface as the modeling surface Ly). The material powder 100 swelled and stacked is moved in the direction of the modeling tank 42 by the horizontal movement of the roller 50 in the R direction, and the modeling table 40 is formed such that the upper surface forms a layer having the height of the modeling surface Ly. Leveled up. Excess material powder 100 is removed as it is by the roller 50 and collected in a material collection tank (not shown). Thus, a layer of the material powder 100 having the modeling surface Ly as the upper surface and having a predetermined thickness is formed on the modeling table 40. However, this is one embodiment, and the supply method of the material powder 100 is not limited to the above-described method.

  Subsequently, the discharge heads 20a to 20f discharge the curable liquid 110B and other liquids onto the material powder 100 formed in the layer. Thereby, modeling and coloring of the object 200 are performed. The ejection heads 20a to 20f are scanned by the main scanning unit 52y in the main scanning direction Y1 while being held by the holding unit 52a. The movement of the main scanning unit 52y is controlled by the movement control unit 70. During scanning in the Y1 direction, the ejection heads 20a to 20f eject liquids stored in the tanks 30a to 30f connected to the ejection heads 20a to 20f, respectively, at a predetermined timing and ejection conditions according to the control of the ejection control unit 72. When the ejection operation is completed at one position in the X direction, the ejection heads 20a to 20f are returned to the Y2 direction by the main scanning unit 52y, and then moved in the sub scanning direction X1 by the sub scanning unit 52x. Even at the X position after the movement, the ejection heads 20a to 20f perform the modeling / coloring operation while being scanned in the main scanning direction Y1. In this way, when the ejection heads 20a to 20f are scanned over the entire modeling area, one layer of modeling is completed. By repeating this one-layer modeling process, the three-dimensional modeling apparatus 10 models the three-dimensional shape of the workpiece 200.

  Incidentally, as already described, in the three-dimensional modeling apparatus that discharges a liquid to a material powder, there has been a problem that the material powder adheres to the discharge head when the liquid is discharged by the discharge head. The inventor of the present invention has obtained the following knowledge (1) and (2) while studying the adhesion problem.

(1) Scattering of the material powder can be suppressed by adjusting the liquid discharge conditions from the discharge head. Specifically, the scattering of the material powder can be suppressed by suppressing the discharge amount per unit time discharged to the modeling position. However, if the discharge amount per unit time is suppressed, the discharge density becomes rough. In order to maintain the discharge density, the scanning speed must be slowed down, and the productivity is lowered.

  (2) At the modeling position where the ejection has been performed once, the adhesion of the material powder to the ejection head is suppressed. That is, the material powder once wetted by discharge is not easily scattered. At this time, the liquid discharged by the first discharge may be a curable liquid or a liquid that is not a curable liquid. According to the experimental results, the effect was the same whether it was a curable liquid or a liquid that was almost water.

  In the three-dimensional modeling apparatus 10 proposed here, the ejection control unit 72 sets the ejection condition of the first ejection head that is first ejected to the modeling position among the ejection heads that are sequentially sent to the modeling position to the modeling position. The discharge conditions are set such that the material powder 100 placed on the modeling table 40 is less likely to be scattered than the discharge conditions of the discharge head that discharges the liquid.

  First, the first ejection head and the ejection heads after the second ejection head will be described. By definition, the first discharge head is the first discharge head that discharges to a modeling position that is predetermined on the modeling table 40. The second discharge head is the second discharge head that discharges to the modeling position. The modeling position refers to each point on the modeling area where the discharge head discharges, and when viewed at one modeling position, the discharge head is sequentially moved upward while discharging. Hereinafter, the third ejection head, the fourth ejection head, the fifth ejection head, and the sixth ejection head follow in the order of ejection to the modeling position. In this example, the six ejection heads 20a to 20f are arranged in a line along the main scanning direction Y1 with 20a at the head. Therefore, if the holding portion 52a is moved in the main scanning direction Y1, the ejection head is scanned at the modeling position in the order of 20a, 20b, 20c, 20d, 20e, and 20f. Therefore, in this example, 20a is the first ejection head, 20b is the second ejection head, 20c is the third ejection head, 20d is the fourth ejection head, 20e is the fifth ejection head, and 20f is the sixth ejection head. Discharge head. If the ejection heads are arranged in this way, the arrangement order of the ejection heads becomes the ejection order as it is. Note that the concepts of the first ejection head, the second ejection head, and the like are solely based on the order of ejection, and are not related to the type, performance, or the like of the ejection head itself. The discharge head can be the same. Further, this order does not limit the arrangement of the ejection heads on the holding unit 52a, and does not mean that all the ejection heads are used.

  In each of the ejection heads 20 a to 20 f, ejection conditions are set by the ejection control unit 72. In the first discharge head 20a, discharge conditions are set such that the material powder 100 is less likely to be scattered than the discharge conditions of the second discharge head 20b. The purpose of discharging the liquid by the first discharge head 20a is not modeling and coloring, but is to wet the material powder 100 so that the material powder 100 does not scatter when the discharge head 20b discharges. Therefore, the discharge conditions set for the first discharge head 20a are required to wet the material powder 100 to such an extent that scattering is suppressed even when the second discharge head 20b performs discharge, The material powder 100 is less likely to adhere to the first ejection head 20a itself due to the ejection. Hereinafter, the discharge for wetting the material powder 100 is referred to as a precoat. According to the knowledge of the inventor of the present application, by suppressing the discharge amount of the liquid per unit time, it is possible to realize a discharge condition in which the material powder 100 is hardly scattered. For example, the discharge amount per unit time of the first discharge head 20a may be 50% of the discharge amount per unit time of the second discharge head 20b. In the discharge heads up to and including the second discharge head 20b and the sixth discharge head 20f, discharge conditions determined from the modeling quality and productivity of the article 200 are set. FIG. 3 is a schematic view of the periphery of the holding portion 52a as viewed from the front F. FIG. Pr in FIG. 3 represents a region that has already been wetted by the precoat. As shown in FIG. 3, when the second discharge head 20b discharges, since the material powder 100 is already wetted by the precoat, it is difficult to scatter even if liquid is discharged under the discharge conditions for modeling. It is in a state. In the following, a liquid discharged in the pre-coating is referred to as a pre-coating liquid, but what is used as the pre-coating liquid 110P is not limited. That is, the precoat liquid 110P does not indicate the type of liquid, but means all liquids used for precoating. The precoat liquid 110P may be water, for example.

  FIG. 4 is a flowchart of processing performed by the ejection control unit 72 in one scan in the main scanning direction Y1. At the START time point in the flowchart, the ejection heads 20a to 20f are scanned in the main scanning direction Y1. Then, when the first discharge head 20a reaches the modeling area where modeling is planned to be performed in the layer, the process enters step S01. In other words, the process enters a step of performing a process for starting the pre-coating on the first ejection head 20a. FIG. 5 is a plan view schematically showing the modeling table 40 at the start of the pre-coating. An area represented by 120 in FIG. 5 is a modeling area. In addition, of the modeling area 120, an already modeled area is 120a. Modeling has already been completed in the modeling region on the X2 side of the X-direction position of the ejection head shown in FIG. Modeling at this X-direction position has not yet started and is about to start. Next, when the second ejection head 20b reaches the modeling area 120, the processing flow enters step S02b. That is, the discharge of the cyan color liquid 110C by the discharge head 20b is started. FIG. 6 is a plan view schematically showing the modeling table 40 at the time when the discharge by the discharge head 20b is started. In FIG. 6, an area indicated by 120 b is an area where pre-coating is finished and modeling and coloring are not yet performed. As shown in FIG. 6, along the main scanning direction Y1, the front of the second ejection head 20b is a pre-coated region 120b. Since the discharge head 20b discharges while proceeding in the Y1 direction, the area where the discharge head 20b discharges is the pre-coated area 120b. Even if the modeling proceeds as it is, the modeling area 120 in front of the ejection head 20b is always pre-coated by the first ejection head 20a. Thus, the ejection head 20b can perform ejection without worrying about the scattering of the material powder 100. Hereinafter, the same applies from the time when the discharge head 20c reaches the modeling area 120 and enters the step S02c where the discharge of the magenta color liquid 110M starts and the time when the discharge head 20f starts the step S02f where the discharge of the curable liquid 110B starts. In the flowchart of FIG. 4, steps S02c to S02f are omitted. And if modeling further advances, the 1st discharge head 20a will pass through modeling area 120, and will enter Step S03. In step S03, the ejection control unit 72 performs a process of finishing precoating on the first ejection head 20a. FIG. 7 is a plan view schematically showing the modeling table 40 at the end of the precoat. The area indicated by 120c in FIG. 7 is an area in the middle of modeling where all the liquid has not yet been discharged. In this example, the order of steps S02b to S02f and step S03 is all first in steps S02b to S02f, but may be partially reversed depending on the cross-sectional shape of the object 200. And if the 2nd discharge head 20b passes the modeling area | region 120, the process which the discharge control part 72 performs will enter step S04b. In step S04b, a process for causing the ejection head 20b to terminate ejection is performed. Hereinafter, every time the ejection heads 20c to 20f pass through the modeling region 120, steps S04c to S04f are performed, and the ejection of the liquid by the ejection heads 20c to 20f is completed. Since steps S04b to S04f are similar processing, steps S04c to S04e are omitted in the flowchart of FIG. FIG. 8 is a plan view schematically showing the modeling table 40 at the time when the sixth discharge head 20f finishes discharging. At the time of FIG. 8, the modeling at the position in the X direction has been completed. Thereafter, the ejection heads 20a to 20f are returned to the Y2 direction by the main scanning unit 52y. Further, the ejection heads 20a to 20f are moved in the X1 direction by the sub-scanning part 52x. Thereafter, modeling and coloring proceed in the same manner.

  As described above, the discharge control unit 72 discharges the discharge conditions of the first discharge head 20a that discharges first to the modeling position among the discharge heads that are sequentially sent to the modeling position to the second position. The discharge conditions are set so that the material powder 100 placed on the modeling table 40 is less likely to be scattered than the discharge conditions of 20b. The material powder 100 at the modeling position is wetted by the discharge of the first discharge head 20a and becomes difficult to be scattered, so that the discharge of the material powder 100 is suppressed when the discharge heads after the second discharge head 20b are discharged. The Thereby, adhesion of the material powder 100 to the ejection heads 20b to 20f is suppressed. In addition, since it is not necessary to consider the scattering of the material powder 100 when discharging from the discharge heads below the second discharge head 20b, productivity is hardly affected. Since the discharge conditions of the first discharge head 20a are set to the discharge conditions that make it difficult for the material powder 100 to scatter, adhesion of the material powder 100 to the first discharge head 20a is also suppressed.

  Pre-coating can also be performed when performing bidirectional modeling. Bidirectional modeling is a method in which modeling is performed not only when the ejection head is scanned in the Y1 direction but also when it is scanned in the Y2 direction. In bidirectional modeling, the main scanning direction may be Y1 or Y2, and changes depending on the progression direction of modeling. Therefore, in the case of bidirectional modeling, it is preferable that the role of the ejection head changes between when the main scanning direction is Y1 and when the main scanning direction is Y2. In the example of FIG. 3, when modeling in the Y1 direction, the first ejection head is 20a. The second ejection head is 20b. Therefore, the discharge controller 72 sets discharge conditions in the discharge head 20a that make it difficult for the material powder 100 to scatter more than the discharge head 20b. On the other hand, when modeling in the Y2 direction, the first ejection head is 20f, and the second ejection head is 20e. The ejection control unit 72 sets ejection conditions in the ejection head 20f such that the material powder 100 is less likely to be scattered than the ejection head 20e. In this way, pre-coating can be performed even in the case of bidirectional modeling. The processing flow performed by the discharge control unit 72 during modeling in the Y1 direction is the same as in the case of FIG. The processing flow performed by the discharge control unit 72 during modeling in the Y2 direction is the same as that in the modeling in the Y1 direction except that the order of the ejection heads is reversed.

  The precoat can also be applied to a so-called line head type three-dimensional modeling apparatus. The line head method is a method in which scanning is performed only in the main scanning direction and no sub-scanning direction, and instead of scanning in the sub-scanning direction, the entire formation area width in the direction intersecting the main scanning direction is covered. In this way, a large number of ejection head groups are arranged. In the line head system, the holding unit 52a holds a number of ejection head groups arranged along the Y direction along the X direction. One ejection head group includes a first ejection head, a second ejection head and the following ejection heads necessary for pre-coating and modeling along the main scanning direction Y1. In the line head method, pre-coating and modeling for one layer are performed by one scan. Therefore, the manufacturing cost of the apparatus tends to be high, but the productivity is high. Moreover, even if it is not a complete line head system, the three-dimensional modeling apparatus 10 may include a plurality of ejection head groups. By having a plurality of discharge head groups, productivity can be improved.

  When the moving mechanism 52 includes a main scanning unit 52y that moves the ejection heads 20a to 20f in the main scanning direction Y1 and a sub-scanning unit 52x that moves the ejection heads 20a to 20f in the sub-scanning direction X1, the first ejection head 20a The second discharge head 20b may be held forward along the sub-scanning direction X1.

  In an embodiment that involves scanning in the sub-scanning direction X1, the first discharge head 20a is held in front of the second discharge head 20b along the sub-scanning direction X1 than the second discharge head 20b. The modeling position can be scanned before the second ejection head 20b. By taking such an arrangement of the ejection heads, the scanning order and the ejection order between the first ejection head 20a and the second ejection head 20b can be easily matched. Further, according to this embodiment, there is a time interval of one scan or more from the discharge of the first discharge head 20a to the discharge of the second discharge head 20b. With this time, the pre-coated liquid permeates the material powder 100, and the scattering of the material powder 100 can be more reliably suppressed.

  A three-dimensional modeling apparatus 10 in which the first ejection head is disposed in front of the sub-scanning direction will be described with reference to FIGS. FIG. 9 is a plan view schematically showing the modeling table 40 during the first scan in the embodiment in which the first ejection head is arranged in the front in the sub-scanning direction. 5 to 8, 120 indicates a modeling area, 120 b indicates an area where only pre-coating is completed in the modeling area 120, and 120 c indicates an area where pre-coating is completed in the modeling area 120 but is in the middle of modeling. Yes. As shown in FIG. 9, the first ejection head 20a is held forward along the sub-scanning direction X1 than the second ejection head 20b. In FIG. 9, the holding unit 52a is subjected to the first scan in which only pre-coating is performed by the first ejection head 20a. By this first scanning, the region on the most X2 side of the modeling region 120 is precoated in a strip shape over the width L1. L1 is the width of the first ejection head 20a in the X direction. Subsequently, in FIG. 10, the holding unit 52a is scanned in the X1 direction by L1 and is scanned in the Y1 direction at the X position. A region where the ejection heads up to the second ejection head 20b and below 20e are scanned in this scanning is a region 120b which has been pre-coated by the first scanning. Thereafter, the third and subsequent scans continue while moving by L1 in the X1 direction. As described above, in the case of modeling with scanning in the sub-scanning direction, pre-coating can also be performed by disposing a pre-coating discharge head in front of the sub-scanning direction X1. Here, the front side in the sub-scanning direction X1 is not limited to the front front side along the sub-scanning direction X1, and refers to a region on the X1 side with respect to the second ejection head 20b. Compared with the embodiment in which the precoat ejection head is disposed in front of the main scanning direction Y1, the first embodiment in which the precoat ejection head is disposed in front of the sub-scanning direction X1 is performed in the first time. Although the number of scans is increased by the amount corresponding to the scan, a time of one scan or more is ensured between the precoat and modeling. In this time, the pre-coated liquid can permeate into the material powder 100, and there is an advantage that the effect of the pre-coating appears more reliably. Of course, bidirectional modeling is also possible in this embodiment. Further, it is also possible to arrange a single discharge head for pre-coating on the X1 side and arrange a plurality of discharge head groups for modeling on the X2 side.

  The plurality of ejection heads provided in the three-dimensional modeling apparatus 10 disclosed herein may include an ejection head that ejects the curable liquid 110B in an ejection head other than the first ejection head 20a.

  The discharge head that is included in the discharge heads other than the first discharge head 20a and discharges the curable liquid 110B discharges the curable liquid 110B onto the material powder 100 that has already been wetted. Therefore, there is little need to consider the scattering of the material powder 100 as the discharge condition, and the user can select a discharge condition that can cure the material powder 100 more reliably.

  The discharge controller 72 may set the discharge amount per unit time that the first discharge head discharges to the modeling position smaller than the discharge amount per unit time that the second discharge head discharges to the modeling position. .

  The discharge amount per unit time of the first discharge head described above may be set to 20% or more and less than 90% of the discharge amount per unit time of the second discharge head.

  By setting a small discharge amount per unit time that the first discharge head discharges to the modeling position, the three-dimensional modeling apparatus 10 can suppress scattering of the material powder 100 during pre-coating, and the first discharge head The adhesion of the material powder 100 to the surface can be suppressed.

  According to the knowledge of the inventor of the present application, by setting the discharge amount of the liquid per unit time that the discharge head discharges to the material powder 100 to be small, adhesion of the material powder 100 to the discharge head can be suppressed. As a result of the inventor of the present application adjusting the discharge amount of the liquid per unit time and visually confirming the adhesion of the material powder 100 to the discharge head, 20% to 90% of the discharge amount per unit time under the previous discharge conditions When adjusted to%, a clear difference from the case of the previous discharge conditions was observed. If the discharge amount per unit time is too small, the material powder 100 will be insufficiently wetted. Therefore, the discharge amount per unit time is more preferably set to 30% or more of the conventional case. In addition, when the discharge amount per unit time is too large, the material powder 100 is scattered. Therefore, it is more preferable to set the liquid discharge amount per unit time to less than 70% of the conventional case. The discharge amount per unit time can be adjusted by several methods. For example, one method is adjustment of the number of ejections per unit time. If the mass of one droplet is fixed, the discharge amount per unit time can be suppressed by suppressing the number of discharges per unit time. On the contrary, the discharge amount per unit time can be adjusted by adjusting the mass of one droplet. Of course, it is also possible to combine the two.

  Examples of the method for adjusting the number of ejections per unit time and the size of the droplet include the following methods. For example, when a piezo drive system is employed as the drive system of the discharge head, the number of discharges per unit time is determined by the drive frequency applied to the piezo element and the power. The driving frequency determines the maximum value of the number of ejections per unit time. This drive frequency is usually a design parameter and is fixed after the three-dimensional modeling apparatus 10 is manufactured. Therefore, the user adjusts the number of ejections per unit time by changing the power multiplied by the drive frequency in accordance with the specification of the object 200 to be modeled. For example, when the driving frequency is 1000 Hz, if the work rate is set to 40%, the thinning discharge is performed only four times out of ten times, and the work is equivalent to 400 Hz. As for the size of the droplet, the minimum droplet size is determined, and the size of the droplet is determined by the number of droplets that are instantaneously shot at the same position. Therefore, in order to reduce the size of the droplets, the number of droplets to be ejected at the same position may be reduced.

  The discharge control unit 72 may set the discharge amount per unit area that the first discharge head discharges to the modeling position to be smaller than the discharge amount per unit area that the second discharge head discharges to the modeling position. .

  The discharge amount per unit area of the first discharge head described above may be set to 20% or more and less than 90% of the discharge amount per unit area of the second discharge head.

  The discharge amount per unit area is the discharge amount of the discharge liquid discharged per unit area of the modeling area, that is, the discharge density to the modeling area. Also by adjusting the discharge amount per unit area, scattering of the material powder 100 during pre-coating can be suppressed. Since both the first ejection head 20a and the second ejection head 20b are held by the holding unit 52a and have the same scanning speed, in the comparison between the first ejection head 20a and the second ejection head 20b, per unit area The discharge amount per unit time and the discharge amount per unit time have the same meaning.

  The first ejection head may eject either the curable liquid 110B or a liquid that is not the curable liquid 110B.

  When the curable liquid 110B is used as the precoat liquid, it is not necessary to prepare the liquid separately, which is advantageous in terms of compatibility. In the case of bidirectional modeling, the use of the curable liquid 110B as the precoat liquid has an advantage that the number of ejection heads can be saved as compared with the case where a liquid other than the curable liquid 110B is used. Moreover, when using the liquid which is not the hardening liquid 110B as a precoat liquid, the liquid can be selected according to the purpose. For example, a cheaper precoat liquid is selected, or a precoat liquid that dries faster is selected.

  Whether the precoat liquid is the curable liquid 110B or a liquid that is not the curable liquid 110B, there is almost no difference in effect. A preferable characteristic as the characteristic of the precoat liquid is, for example, transparency. It is preferable that the precoat liquid is transparent and does not color the shaped object. The precoat liquid preferably has a surface tension within a range of surface tension suitable for discharging from the discharge head. Furthermore, the precoat liquid is preferably within a viscosity range suitable for discharging from the discharge head. Another desirable characteristic is that it has moderate volatility. For liquids that are highly volatile at room temperature, the ejection head dries. Moreover, the liquid which does not volatilize easily even if heated takes time for the drying process after modeling. Therefore, it is desirable to have moderate volatility between the two. The precoat liquid may be selected in consideration of the above characteristics, cost, availability, and the like.

  In the case of bidirectional modeling, the use of the curable liquid 110B as the precoat liquid has the advantage that the number of ejection heads can be saved as compared with the case where a liquid other than the curable liquid 110B is used. FIG. 11 shows one arrangement example of the ejection head in the case of bidirectional modeling. FIG. 12 is an arrangement example of the ejection head different from FIG. 11 in the case of bidirectional modeling. In the example of FIG. 11, the liquids required for modeling and coloring are the curable liquid 110B, the cyan color liquid 110C, the magenta color liquid 110M, the yellow color liquid 110Y, and the black color liquid 110K. In FIG. 11, the precoat liquid is a precoat liquid 110P that is not the curable liquid 110B, and in FIG. 12, the precoat liquid is the curable liquid 110B. In the case of FIG. 11, the required discharge heads are seven, 20a to 20g. The precoat liquid 110P is discharged from the first discharge head 20a in modeling in the Y1 direction and the first discharge head 20g in modeling in the Y2 direction. On the other hand, as shown in FIG. 12, if the curable liquid 110B is used as the precoat liquid, bidirectional modeling can be achieved even if the discharge head 20g is eliminated and the number of discharge heads is six. In the example of FIG. 12, the precoat liquid discharged from the first discharge head 20a in the Y1 direction modeling and the first discharge head 20f in the Y2 direction modeling is the curable liquid 110B. When modeling in the Y1 direction, the ejection head 20a performs pre-coating, and the ejection head 20f performs curing. Conversely, when modeling in the Y2 direction, the ejection head 20f pre-coats and the ejection head 20a cures. In this way, by discharging the curable liquid 110B to the ejection heads at both ends, it is possible to save one ejection head per one ejection head group. Since the present embodiment has one row, the number of discharge heads that can be saved is one. For example, in the case of the line head method, the number of rows can be reduced by the number of rows, and the manufacturing cost of the apparatus can be further reduced. Is expected.

  The liquid that is not the curable liquid 110B used as the precoat liquid may be water.

  If the precoat solution is made into water, it is inexpensive and easily available.

  The precoat liquid may be water. Here, water includes water in which some additives are added to adjust the physical properties. The additive is, for example, a surfactant for adjusting the surface tension, a preservative for preventing corrosion of water, and the like. The amount added is, for example, about 0.1 to 3 wt%.

  As described above, the discharge condition of the first discharge head that discharges first to the modeling position causes the material powder 100 placed on the modeling table 40 to scatter more than the discharge condition of the discharge head that discharges second to the modeling position. If the discharge conditions are set to be difficult, the adhesion of the material powder 100 to the discharge head is suppressed, and the degree of freedom of the discharge conditions of the discharge heads after the second discharge head is increased.

Further, the first ejection head is held in front of the second ejection head along the main scanning direction Y1, so that the scanning order and ejection order between the first ejection head and the second ejection head are increased. Can be easily matched. Further, in that case, the ejection heads may be held in a line along the main scanning direction Y1. By adopting such an arrangement, it is possible to easily match the scanning order of the ejection heads with the ejection order. Such a one-row arrangement is also useful for arranging the discharge heads in a compact manner.

  When the moving mechanism 52 includes a sub-scanning unit 52x that moves the ejection head in the sub-scanning direction X1 in addition to the main scanning unit 52y that moves the ejection head in the main scanning direction Y1, the first ejection head You may hold | maintain ahead along the subscanning direction X1 rather than the discharge head. By taking such an arrangement of the ejection heads, the scanning order and the ejection order between the first ejection head and the second ejection head can be easily matched. Furthermore, according to this embodiment, it is possible to take time for the pre-coated liquid to soak into the material powder 100, and to more reliably suppress scattering of the material powder 100.

  The discharge amount per unit time of the first discharge head is preferably 20% or more and less than 90% of the discharge amount per unit time of the second discharge head, and moreover, per unit area of the first discharge head. The discharge amount is preferably 20% or more and less than 90% of the discharge amount per unit area of the second discharge head. The precoat liquid 110P may be a curable liquid 110B or a liquid that is not the curable liquid 110B. The precoat liquid 110P may be water.

  The three-dimensional modeling apparatus described above is based on the following three-dimensional model manufacturing method. That is, in the manufacturing method of the three-dimensional structure, the material is placed on the plurality of discharge heads while moving a plurality of discharge heads including at least a discharge head for discharging a curable liquid with respect to a modeling table on which material powder is placed. A method for manufacturing a three-dimensional structure in which liquid is discharged onto powder, and the discharge condition of a discharge head that discharges first to a predetermined modeling position on the modeling table is second to the modeling position It is a manufacturing method of a three-dimensional structure characterized by being set to discharge conditions in which material powder is less likely to be scattered than the discharge conditions of the discharge head.

  In the method for manufacturing a three-dimensional structure, the discharge amount per unit time of the discharge head that discharges first to the modeling position is 20% of the discharge amount per unit time of the discharge head that discharges second to the modeling position. It may be set to less than 90%.

  In the above three-dimensional structure manufacturing method, the discharge amount per unit area of the discharge head that discharges first to the modeling position is 20% of the discharge amount per unit area of the discharge head that discharges second to the modeling position. It may be set to less than 90%.

  According to this method of manufacturing a three-dimensional structure, the discharge head that discharges first wets the material powder at the modeling position, making it difficult for the material powder to scatter. Thereby, scattering of the material powder is suppressed at the time of discharge of the discharge head that discharges the second or later, and adhesion of the material powder to the discharge head can be suppressed. In addition, when discharging from the second and subsequent discharge heads, there is little need to consider the scattering of the material powder, and the productivity is hardly affected. Since the discharge conditions of the first discharge head are set to the discharge conditions that make it difficult for the material powder to scatter, adhesion of the material powder to the first discharge head can also be suppressed.

  This manufacturing method of a three-dimensional structure is applicable to other than the three-dimensional structure forming apparatus disclosed herein. In this method, since the temporal order in which the ejection heads eject the liquid is a problem, it is not always necessary that the ejection heads be arranged in the ejection order along the scanning direction. For example, the position of the ejection head for performing the pre-coating is arbitrary, and a method of performing the pre-coating on the entire modeling area first is also possible.

  The embodiment of the three-dimensional modeling apparatus that suppresses the adhesion of the material powder to the discharge head has been described above. Of course, the three-dimensional modeling apparatus disclosed here is not limited to the form described above.

DESCRIPTION OF SYMBOLS 10 Three-dimensional modeling apparatus 20a-20f Discharge head 30a-30f Tank 40 Modeling table 42 Modeling tank 44 1st raising / lowering mechanism 46 Material tank 48 2nd raising / lowering mechanism 50 Roller 52 Movement mechanism 52a Holding part 70 Movement control part 72 Discharge control part 100 Material powder 110B Hardening liquid 200 Model object

Claims (14)

A modeling table on which material powder is placed,
A plurality of discharge heads including at least a discharge head for discharging a curable liquid for curing the material powder;
A holding mechanism that holds the plurality of discharge heads, and a moving mechanism that moves the plurality of discharge heads held by the holding unit with respect to the modeling table;
A movement control unit that controls the movement mechanism so as to sequentially send a predetermined ejection head among the plurality of ejection heads to a predetermined modeling position on the modeling table;
Among the discharge heads that are sequentially sent to the modeling position, the discharge condition of the first discharge head that discharges first to the modeling position is higher than the discharge condition of the second discharge head that discharges second to the modeling position. A discharge control unit for setting the discharge conditions such that the material powder placed on the modeling table is less likely to be scattered,
With
3D modeling equipment. The moving mechanism includes a main scanning unit that moves the plurality of ejection heads along a predetermined main scanning direction with respect to the modeling table,
The first ejection head is held in front of the second ejection head along the main scanning direction.
The three-dimensional modeling apparatus according to claim 1. The plurality of ejection heads are held in a line along the main scanning direction.
The three-dimensional modeling apparatus according to claim 2. The moving mechanism includes a main scanning unit that moves the plurality of ejection heads along a predetermined main scanning direction with respect to the modeling table, and the plurality of ejections along a sub-scanning direction that intersects the main scanning direction. A sub-scanning unit for moving the head,
The first ejection head is held in front of the second ejection head in the sub-scanning direction;
The three-dimensional modeling apparatus according to claim 1. The plurality of ejection heads include an ejection head that ejects the curable liquid among ejection heads other than the first ejection head.
The three-dimensional modeling apparatus according to any one of claims 1 to 4. The discharge control unit sets a discharge amount per unit time that the first discharge head discharges to the modeling position smaller than a discharge amount per unit time that the second discharge head discharges to the modeling position. To
The three-dimensional modeling apparatus according to any one of claims 1 to 5. The discharge control unit is configured such that a discharge amount per unit time that the first discharge head discharges to the modeling position is 20% or more of a discharge amount per unit time that the second discharge head discharges to the modeling position. Set to less than 90%,
The three-dimensional modeling apparatus according to claim 6. The discharge control unit sets a discharge amount per unit area that the first discharge head discharges to the modeling position smaller than a discharge amount per unit area that the second discharge head discharges to the modeling position. To
The three-dimensional modeling apparatus according to any one of claims 1 to 5. The discharge control unit is configured such that a discharge amount per unit area discharged from the first discharge head to the modeling position is 20% or more of a discharge amount per unit area discharged from the second discharge head to the modeling position. Set to less than 90%,
The three-dimensional modeling apparatus according to claim 8. The first discharge head discharges either the curable liquid or a liquid that is not the curable liquid.
The three-dimensional modeling apparatus according to any one of claims 1 to 9. The liquid that is not the curable liquid is water.
The three-dimensional modeling apparatus according to claim 10. Moving a plurality of discharge heads including at least a discharge head for discharging a curable liquid for curing the material powder with respect to the modeling table on which the material powder is placed;
A method of manufacturing a three-dimensional structure, wherein the plurality of ejection heads eject liquid to the material powder while moving the plurality of ejection heads,
The material powder placed on the modeling table has a discharge condition of a discharge head that first discharges to a predetermined modeling position on the modeling table, rather than a discharge condition of a discharge head that discharges second to the modeling position. It is set to discharge conditions that make it difficult to scatter,
A manufacturing method of a three-dimensional structure. The discharge amount per unit time of the discharge head that discharges first to the modeling position is set to 20% or more and less than 90% of the discharge amount per unit time of the discharge head that discharges second to the modeling position.
The manufacturing method of the three-dimensional structure according to claim 12. The discharge amount per unit area of the discharge head that discharges first to the modeling position is set to 20% or more and less than 90% of the discharge amount per unit area of the discharge head that discharges second to the modeling position.
The manufacturing method of the three-dimensional structure according to claim 12.

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