Construction methods

Abstract

This provides a 3D printing method for forming structures that allows for improvement of the uneven surface shape on the sides of structures and enables the creation of structures with complex shapes. [Solution] The method comprises a lamination step in which a lamination material 15 is laminated in the lamination direction Z by an extrusion device 10 equipped with an extrusion nozzle 11 that can move relative to the structure 50, and a correction step in which droplets of correction material 25 are sprayed at multiple locations in the direction Z that are different, toward recesses C4 formed on the side surface 55 of the structure 50 in the lamination step, by an injection device 20 equipped with a plurality of injection nozzles 21a to 21g that can move relative to the structure 50, and the lamination step and the correction step are repeated multiple times to form the structure 50.

Description

Technical Field

[0001] The present invention relates to a method for forming a structure.

Background Art

[0002] In recent years, the applications of 3D printers have been rapidly expanding, and their deployment in construction applications using the material extrusion method has attracted attention. The material extrusion method has advantages such as enabling the shaping of large structures, but conventionally, there has been a problem that concave and convex shapes are formed on the side surfaces of structures. In contrast, for example, Patent Document 1 proposes a method for forming a structure to improve such concave and convex shapes.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above-described method for forming a structure may be difficult to apply to structures with complex shapes. An object of the present invention is to provide a method for forming a structure by a 3D printer that can improve the concave and convex shapes on the side surfaces of a structure and enable the formation of a structure with a complex shape.

Means for Solving the Problems

[0005] The present invention relates to a method for forming a structure, comprising: a lamination step of forming a structure by laminating a lamination material in the lamination direction using an extrusion device equipped with an extrusion nozzle that can move relative to the structure; and a correction step of spraying droplets of a correction material at multiple locations in the lamination direction that are different in position towards recesses formed on the side surface of the structure in the lamination step using a spraying device equipped with a plurality of spray nozzles that can move relative to the structure together with the extrusion nozzle; wherein the lamination step and the correction step are repeated multiple times. [Effects of the Invention]

[0006] According to an aspect of the present invention, a method for forming structures using a 3D printer is provided that allows for improvement of the uneven shape of the side surface of a structure and enables the formation of structures with complex shapes. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing the structure formation method of the first embodiment. [Figure 2] This is a top view showing a method for forming a structure according to the first embodiment. [Figure 3] This is a front view showing the structure formation method of the first embodiment. [Figure 4] This is a front view (enlarged view of Figure 3) showing the structure formation method of the first embodiment. [Figure 5] This is a side view showing the structure formation method of the first embodiment. [Figure 6] This is a side view (enlarged view of Figure 5) showing the structure formation method of the first embodiment. [Figure 7] This is a front view (an enlarged view corresponding to Figure 4) showing the structure formation method of the first embodiment. [Figure 8] This is a side view of a structure formed by the structure formation method of the first embodiment. [Figure 9] This is a side view showing the state of formation of a complex-shaped structure using the structure formation method of the first embodiment. [Figure 10] This is a top view showing the state of formation of a complex-shaped structure using the structure formation method of the first embodiment. [Figure 11] This is a perspective view showing the method for forming a structure according to the second embodiment. [Figure 12] This is a block diagram that functionally illustrates the configuration related to the method for forming a structure according to the second embodiment. [Modes for carrying out the invention]

[0008] [First Embodiment] The method for forming a structure according to the first embodiment of the present invention will be described below with reference to Figures 1 to 8.

[0009] Figure 1 is a perspective view showing a method for forming a structure.

[0010] As shown in Figure 1, the structure 50 consists of layers L1, L2, and L3. The extrusion nozzle 11 of the extrusion device 10 is movable relative to the structure 50 by a positioning means (not shown). The extrusion device 10 is a device that constitutes a material extrusion type 3D printer, and the positioning means may be a robot arm type or a gantry type. The extrusion nozzle 11 moves along the X direction from a position spaced apart in the Z direction from the layer L3, and continuously extrudes the lamination material 15 onto the layer L3. The lamination material 15 extruded onto the layer L3 becomes one with the layer L3 to form layer L4, which becomes part of the structure 50. Layers L1, L2, and L3 are stacked sequentially along the stacking direction Z, following a process similar to that for layer L4. The number of such layers is not limited to four (layers L1 to L4), but can be any number of layers.

[0011] The lamination material 15 is a material such as mortar, concrete, or geopolymer, which is fluid when extruded from the extrusion nozzle 11, but hardens over time after extrusion.

[0012] The above process corresponds to the lamination process.

[0013] FIG. 2 is a top view showing a method of forming a structure (a partial cross-sectional view along the interface between layer L3 and layer L4).

[0014] As shown in FIGS. 1 and 2, the injection device 20 includes a total of seven injection nozzles 21a, 21b, 21c, 21d, 21e, 21f, and 21g. The injection nozzles 21a to 21g are connected to the extrusion nozzle 11 by a connecting member 70. Thus, when the extrusion nozzle 11 moves along the direction X, the injection nozzles 21a to 21g also move along the direction X together with it. The number of the injection nozzles is not limited to seven of the injection nozzles 21a to 21g, and any number may be used as long as there are a plurality of them.

[0015] FIG. 3 is a front view showing a method of forming a structure, and FIG. 4 is an enlarged view of region A in FIG. 3.

[0016] As shown in FIGS. 3 and 4, the injection nozzles 21a to 21g are linearly arranged along a direction R which is a direction inclined with respect to the direction Z. Therefore, as shown in FIG. 4, the interval N in the direction Z of adjacent injection nozzles among the injection nozzles 21a to 21g is smaller than the interval M in the direction R of adjacent injection nozzles among the injection nozzles 21a to 21g.

[0017] The injection device 20 is a device that constitutes a 3D printer of a material injection type, and a valve type inkjet head capable of injecting a liquid with a relatively high viscosity (a method of constantly pressurizing the liquid and opening and closing the nozzle by an electromagnetic valve, a piezoelectric element, etc. as needed to inject droplets) is suitable, but a piezo type inkjet head (a method of pressurizing the liquid by a piezoelectric element as needed and injecting droplets from a nozzle that is constantly open) etc. may also be used.

[0018] FIG. 5 is a side view showing a method of forming a structure, and FIG. 6 is an enlarged view of region B in FIG. 5.

[0019] As shown in Figures 5 and 6, in the lamination process described above, the extrusion nozzle 11 continuously discharges the lamination material 15 onto layer L3, and when the lamination material 15 becomes layer L4, a streak-like recess C4 is formed at the boundary between layer L3 and layer L4 on the side surface 55 of the structure 50. This corresponds to the uneven shape of the side surface 55 of the structure 50.

[0020] As shown in Figures 1 to 6, in order to improve the recess C4, droplets of the correction material 25 are sprayed from the required spray nozzles 21a to 21g toward the recess C4, and the droplets land on the recess C4.

[0021] As shown in Figures 4 and 6, as an example, we will describe the case where the droplets ejected from nozzles 21b, 21c, 21d, 21e, and 21f land within the position of recess C4 (within the range of width T), the droplet ejected from nozzle 21a land at a position opposite to the position of recess C4 in the direction Z, and the droplet ejected from nozzle 21g land at a position off in the direction Z from the position of recess C4.

[0022] As shown in Figures 1 to 6, in the above case, droplets 25b, 25c, 25d, 25e, and 25f are ejected from nozzles 21b, 21c, 21d, 21e, and 21f, respectively, and droplet ejection from nozzles 21a and 21g is not required. (In the figures, droplets 25b to 25f that landed within a unit time are shown by dashed lines.)

[0023] As the spray nozzles 21a to 21g move along direction X, spraying droplets 25b to 25f, each droplet 25b to 25f that lands on the recess C4 is aligned along direction X. Furthermore, since each of the spray nozzles 21a to 21g is in a different position in direction Z, each droplet 25b to 25f is aligned at a position offset from direction Z. As a result, at least a portion of the recess C4 is efficiently covered by droplets 25b to 25f, and the recess C4 is improved into a modified portion D4. Modified sections D2 and D3 are improved from recesses C2 (Figure 5) and C3 (Figure 5), respectively, through the same process as described for modified section D4. The number of such modified sections is not limited to the three sections D2 to D4, but can be any number.

[0024] The repair material 25 is a material such as cement mortar or polymer cement mortar, which is liquid when sprayed from the spray nozzles 21a to 21g, but hardens over time after spraying.

[0025] If the correction material 25 is a material that causes nozzle clogging when droplets are not ejected from the injection nozzles 21a and 21g for an extended period of time, droplets may be ejected from the injection nozzles 21a and 21g at a low frequency.

[0026] The shape of the recess C4 may vary due to fluctuations in the extrusion speed of the lamination material 15 from the extrusion nozzle 11, changes in temperature and humidity of the construction environment, and consequently, the width T of the recess C4 may vary. To address this, the arrangement width S of the injection nozzles 21a to 21g in direction Z may be made larger than the average value of the width T of the recess C4.

[0027] As shown in Figure 6, the depth 53d of the recess C4 corresponding to the impact position of the droplet ejected from the injection nozzle 21d may be defined as the average value of the depth of the recess C4 in the range from position P, which is N / 2 away in the direction opposite to Z with respect to the impact position R of the droplet ejected from the injection nozzle 21d, to position Q, which is N / 2 away in the direction Z with respect to the impact position R. The same applies to the depths 53b, 53c, 53e, and 53f of the recess C4 corresponding to the impact positions of the droplets ejected from the injection nozzles 21b, 21c, 21e, and 21f, respectively.

[0028] In the above case, the depth 53d of recess C4 is greater than the depths 53c and 53e of recess C4, and the depths 53c and 53e of recess C4 are greater than the depths 53b and 53f of recess C4.

[0029] The volume per unit time of each droplet 25b to 25f may be varied depending on the relative depths of the recess C4, from 53b to 53f. In this case, the larger the depth of the recess C4 (53b to 53f), the larger the volume of the droplets 25b to 25f per unit time may be. For example, the volume of droplet 25d per unit time may be greater than the volume of droplets 25c and 25e per unit time. Also, the volume of droplets 25c and 25e per unit time may be greater than the volume of droplets 25b and 25f per unit time.

[0030] As shown in Figure 4, the volume of each droplet 25b to 25f per unit time can be changed by varying the number of droplets 25b to 25f per unit time. For example, the number of droplets 25d per unit time (19 droplets) may be greater than the number of droplets 25c and 25e per unit time (9 droplets). Also, the number of droplets 25c and 25e per unit time (9 droplets) may be greater than the number of droplets 25b and 25f per unit time (2 droplets).

[0031] Figure 7 is a front view (an enlarged view corresponding to Figure 4) showing the method of forming the structure.

[0032] As shown in Figure 7, in the above case, the volume per unit time of each of the droplets 25b to 25f may be changed by changing the volume of one droplet of each of the droplets 25b to 25f. For example, the volume of one large droplet of droplet 25d may be greater than the volume of one medium droplet of droplets 25c and 25e. Also, the volume of one medium droplet of droplets 25c and 25e may be greater than the volume of one small droplet of droplets 25b and 25f.

[0033] The above steps correspond to the correction process.

[0034] Figure 8 is a side view showing a structure formed by the structure formation method. Figure 8(a) shows the structure 50 without the above modification step, and Figures 8(b) and 8(c) show the structure 50 when the recesses C2 to C4 on the side surface 55 are modified in the above modification step.

[0035] As shown in Figure 8(a), if the above modification process is not performed, the recesses C2 to C4 will remain as they are. As shown in Figure 8(b), in the above modification process, the recesses C2 to C4 may be improved to become flat modified sections D2 to D4, respectively. As shown in Figure 8(c), in the above modification process, recesses C2 to C4 may be improved to modified sections E2 to E4, each with a reduced depth compared to recesses C2 to C4. Modified sections E2 to E4 can be formed in the same process as modified sections D2 to D4, but when forming modified sections E2 to E4, the volume of droplets 25b to 25f per unit time may be less than when forming modified sections D2 to D4. Also, droplets may not be ejected from some of the injection nozzles 21b to 21f.

[0036] The effects of the structure formation method according to the first embodiment of the present invention will be described below with reference to Figures 9 to 10.

[0037] The structure formation method of this embodiment includes a lamination step of forming a structure 50 by laminating lamination material 15 in the lamination direction Z using an extrusion device 10 equipped with an extrusion nozzle 11 that can move relative to the structure 50, and a correction step of spraying droplets of correction material 25 at multiple locations in the direction Z that are different, toward the recess C4 formed on the side surface 55 of the structure 50 in the lamination step using a spray device 20 equipped with a plurality of spray nozzles 21a to 21g that can move relative to the structure 50, thereby enabling efficient improvement of the recess C4. Furthermore, by repeating the lamination process and the modification process multiple times, it is possible to improve the recesses C2 to C4 formed on the side surface 55 of the structure 50.

[0038] Figure 9 is a side view showing the state of formation of a complex-shaped structure by the structure formation method of the first embodiment.

[0039] As shown in Figure 9, even when layers L3 and L4 are misaligned when viewed from direction Z, the recess C4 can be improved by spraying droplets onto the recess C4 from the necessary injection nozzles among the injection nozzles 21a to 21g.

[0040] Figure 10 is a top view showing the state of formation of a complex-shaped structure by the structure formation method of the first embodiment.

[0041] As shown in Figure 10, even when the movement direction of the extrusion nozzle 11 and the injection nozzles 21a to 21g is curved and layers L1 to L4 are formed in a curved shape, the recess C4 can be improved by injecting droplets onto the recess C4 from the necessary injection nozzles among the injection nozzles 21a to 21g.

[0042] As described above, the structure formation method of the first embodiment is a non-contact method, and even when forming structures with complex shapes, it is possible to improve the recess C4.

[0043] By not spraying droplets of the correction material 25 from the spray nozzles 21a and 21g, where the droplet landing position is outside the position of the recess C4, it is possible to improve the shape to match that of the recess C4.

[0044] By spraying droplets of the corrective material 25 at a low frequency from spray nozzles 21a and 21g, where the droplet landing position is outside the recess C4, nozzle clogging by the corrective material 25 is prevented, the adhesion of corrective material 25 droplets to positions outside the recess C4 is made less noticeable, and improvements can be made to match the shape of the recess C4.

[0045] By making the array width S of the injection nozzles 21a to 21g in direction Z larger than the average value of the width T of the recess C4, the risk of the width T fluctuating and becoming larger than the array width S, resulting in insufficient improvement of the recess C4, can be reduced.

[0046] By varying the volume of droplets 25b to 25f per unit time depending on the depth of recess C4 (53b to 53f), improvements can be made to match the shape of recess C4. The greater the depth of the recess C4 (53b-53f), the more improvements can be made to match the shape of the recess C4 by increasing the volume of the droplets (25b-25f) per unit time. The volume of droplets 25b to 25f per unit time can be improved to match the shape of the recess C4 whether it is changed by varying the number of droplets 25b to 25f per unit time, or by varying the volume of each individual droplet 25b to 25f.

[0047] By arranging the injection nozzles 21a to 21g along a straight line in direction R that is inclined with respect to direction Z, the spacing N between the injection nozzles 21a to 21g in direction Z becomes smaller than the spacing M between the injection nozzles 21a to 21g in direction R, allowing the injection nozzles 21a to 21g to be densely arranged in direction Z. This increases the total amount of correction material 25 used to correct the recess C4, making it possible to improve the recess C4 even when the recess C4 is deep.

[0048] [Second Embodiment] The method for forming a structure according to the second embodiment of the present invention will be described below with reference to Figures 11 and 12. However, components having the same configuration as those in the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0049] Figure 11 is a perspective view showing a method for forming a structure. Figure 12 is a block diagram that functionally shows the components related to the method for forming the structure.

[0050] As shown in Figure 11, a shape measuring means 80 is provided in the X direction between the extrusion nozzle 11 of the extrusion device 10 and the injection nozzles 21a to 21g of the injection device 20. The shape measuring means 80 is connected to the extrusion nozzle 11 and the injection nozzles 21a to 21g by connecting members 70 and 71. As a result, the shape measuring means 80 moves along the X direction as the extrusion nozzle 11 and the injection nozzles 21a to 21g move along the X direction.

[0051] The shape measuring means 80 is a reflective laser displacement sensor, a stereo vision sensor, or the like, capable of measuring the shape of the recess C4 along the direction Z.

[0052] As shown in Figure 12, the configuration related to the structure formation method includes a shape measuring means 80, a droplet volume determination means 23, and an injection device control unit 22 equipped with an injection device control means 24, and an injection device 20 equipped with injection nozzles 21a to 21g.

[0053] After the above lamination process, the depth of the recess C4 at a position in direction Z corresponding to the landing position of the droplets ejected from each of the injection nozzles 21a to 21g is measured by the shape measuring means 80. This process corresponds to the shape measuring process.

[0054] Based on the results of the above measurements, the droplet volume determination means 23 determines the volume of droplets per unit time ejected from each of the injection nozzles 21a to 21g. The volume of droplets per unit time includes the presence or absence of droplets, the number of droplets per unit time, the volume of a single droplet, etc. This step corresponds to the droplet volume determination step.

[0055] Based on the above decision, the injection device control means 24 controls each of the injection nozzles 21a to 21g of the injection device 20, and performs a correction process in which each of the injection nozzles 21a to 21g sprays droplets of the required volume per unit time.

[0056] The effects of the structure formation method according to the second embodiment of the present invention will be described below.

[0057] The shape of the recess C4 is measured by the shape measuring means 80, and the volume of droplets sprayed per unit time from the spray nozzles 21a to 21g is adjusted according to the result, thereby reducing the amount of work required to improve the recess C4. Furthermore, even if the shape of the recess C4 changes while one layer (L4) is being formed, the shape of the recess C4 can be measured at predetermined intervals using the shape measuring means 80, and the volume of droplets sprayed per unit time from the spray nozzles 21a to 21g can be adjusted accordingly to improve the shape of the recess C4.

[0058] [Variation] Next, modified examples of each of the above embodiments will be described.

[0059] In the first embodiment, the extrusion nozzle 11 and the injection nozzles 21a to 21g may be fixed, and the structure 50 may move. In the second embodiment, the extrusion nozzle 11, injection nozzles 21a to 21g and shape measuring means 80 may be fixed, while the structure 50 moves.

[0060] In the first embodiment, direction R does not have to be inclined with direction Z, but may be parallel to direction Z. In the first embodiment, the injection nozzles 21a to 21g may not be arranged in a straight line, but may be arranged in a curved or matrix-like manner, or other similar arrangements.

[0061] In the first embodiment, the positional relationship between the injection nozzles 21a to 21g and the recess C4 is not limited to the above example. The selection of whether or not droplets are ejected from each of the injection nozzles 21a to 21g, the selection of droplet ejection at a low frequency, the volume of droplets per unit time, the number of droplets per unit time, and the volume of a single droplet are not limited to the above example.

[0062] In the first embodiment, the definition of the depth of the recess C4 is not limited to the above example. The depth of the recess C4 may be defined as the maximum value of the depth of the recess C4 within the above range, etc.

[0063] In the first embodiment, the volume of droplets ejected per unit time from each of the injection nozzles 21b to 21f may be a constant value. This allows for easy modification of the recess C4.

[0064] In the first and second embodiments, multiple injection devices 20 may be provided along the direction X. This increases the total amount of correction material 25 used to correct the recess C4, and makes it possible to improve the recess C4 even when the depth of the recess C4 is large.

[0065] In the first embodiment, the extrusion nozzle 11 and the injection nozzles 21a to 21g are not connected, and the extrusion nozzle 11 and the injection nozzles 21a to 21g may move separately relative to the structure 50. In the second embodiment, the shape measuring means 80 and the injection nozzles 21a to 21g are not coupled, and the shape measuring means 80 and the injection nozzles 21a to 21g may move separately relative to the structure 50. In the second embodiment, the shape measuring means 80 may be a TOF sensor or the like, and the shape measuring means 80 may be fixed to the structure 50 when taking measurements.

[0066] The present invention is not limited to the above embodiments and modifications, and various modifications are possible. [Explanation of Symbols]

[0067] 10 Extruder 11 Extrusion nozzle 15 Lamination Materials 20 Injector 21a, 21b, 21c, 21d, 21e, 21f, 21g spray nozzles 25 Correction materials 25b, 25c, 25d, 25e, 25f droplets 50 Structures 55 Side view 70 Connecting member C2, C3, C4 recesses D2, D3, D4 Correction Section L1, L2, L3, L4 layers X direction of movement Z stacking direction

Claims

1. A lamination process in which lamination materials are stacked in the lamination direction by an extrusion apparatus equipped with an extrusion nozzle that can move relative to the structure, A correction step comprising: spraying droplets of correction material at multiple locations at different positions in the lamination direction toward recesses formed on the side surface of the structure during the lamination process, using a spraying device equipped with multiple spraying nozzles that can move relative to the structure; Equipped with, A method for forming a structure, which involves repeating the lamination process and the modification process multiple times.

2. The method for forming a structure according to claim 1, wherein the droplets are not ejected from any of the injection nozzles, the injection nozzle whose droplet landing position is outside the position of the recess.

3. The method for forming a structure according to claim 1, wherein the droplet is ejected at a low frequency from one of the injection nozzles, the injection nozzle whose droplet landing position is located away from the position of the recess.

4. The method for forming a structure according to claim 1, wherein the arrangement width of the injection nozzles in the stacking direction is greater than the average value of the width of the recesses.

5. The method for forming a structure according to claim 1, wherein the volume of the droplet per unit time is changed by the depth of the recess corresponding to the impact position of the droplet.

6. The method for forming a structure according to claim 5, wherein the greater the depth of the recess, the greater the volume of the droplet per unit time.

7. The method for forming a structure according to claim 5, wherein the volume of the droplets per unit time is changed according to the number of droplets per unit time.

8. The method for forming a structure according to claim 5, wherein the volume of the droplets per unit time is changed by the volume of one of the droplets.

9. The method for forming a structure according to claim 1, wherein the injection nozzles are arranged along a straight line in a direction inclined with respect to the stacking direction.

10. The method for forming a structure according to claim 1, wherein the injection device is a valve-type inkjet head.

11. The method for forming a structure according to claim 1, wherein the extrusion nozzle and the injection nozzle are connected.

12. The method for forming a structure according to claim 1, wherein a plurality of the injection devices are provided along the relative movement direction between the injection device and the structure.

13. Between the lamination process and the modification process, A shape measuring step of measuring the shape of the recess using a shape measuring means, A droplet volume determination step, in which the volume of the droplet per unit time is determined based on the results of the shape measurement step, Equipped with, The method for forming a structure according to claim 1, wherein the droplet is ejected from the injection nozzle based on the result of the droplet volume determination step.

14. The method for forming a structure according to claim 13, wherein the shape measuring means is capable of relative movement with respect to the structure.

15. The method for forming a structure according to claim 14, wherein the shape measuring means and the injection nozzle are connected.

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