JP7542891B1 - 3D modeling data generation program and 3D modeling method - Google Patents

Abstract

[Problem] To provide a technology for suppressing wobbling or tipping over of an object to be molded.
[Solution] The data generation program for three-dimensional modeling determines a path for forming a through passage TH inside a support SP supporting a three-dimensional object OB to be modeled, with an inlet HI facing upward and an outlet HO on a surface facing the three-dimensional object OB, and adds a command for pouring material into the through passage TH after the modeling of the layer LT, which includes the upper end of the through passage TH. When modeling is performed using the data generated in this way, the material poured after the modeling of the layer LT fills the through passage TH and overflows from the outlet HO and adheres to the three-dimensional object OB. Since the layer to which the material adheres is modeled at roughly the same time as the layer forming the lower part of the through passage TH, it is sufficiently cooled at the time the material adheres, so that the attached material is unlikely to be integrated with the three-dimensional object OB even if it solidifies. Therefore, the support SP can suppress the wobbling and tipping of the three-dimensional object OB during modeling, and the support SP can be easily removed after modeling.
[Selected figure] Figure 8

Description

The present invention relates to a program for generating data for three-dimensional modeling used in modeling by a three-dimensional modeling device such as a 3D printer, and a method for manufacturing a three-dimensional object.

As a method for creating three-dimensional objects, fused filament fabrication (hereinafter referred to as the "FFF method") is known, in which layers of material melted by heat are stacked to create a shape (see, for example, Patent Document 1). When creating objects using the FFF method, there is a risk that the object will wobble or fall over during the creation process when creating objects with a high center of gravity or long lengths in the stacking direction, such as pencils, chimneys, and towers.

As a countermeasure to such problems, a well-known method has been to mold multiple objects (hereafter referred to as "disposable objects") whose sole purpose is to support the object to be printed, with a gap between them, together with the object to be printed (each layer of both is molded one after the other by molding a layer at the same height of the object to be printed and the disposable objects, and then molding the next layer of the object to be printed and the disposable objects), and in some layers, the ends of the disposable objects are attached to the sides of the object to be printed, so that the object to be printed is supported by the disposable objects during printing, and the disposable objects are removed from the object to be printed after printing.

Special Publication No. 2000-500709

In the above-mentioned method, a layer of a sacrificial object whose ends adhere to the side of the layer to be printed is printed immediately after the layer of the object to be printed. Since the temperature difference between the two is small, the ends of the sacrificial object tend to become integrated with the side of the object to be printed. As a result, it becomes difficult to remove the sacrificial object after printing, and attempting to remove it forcibly may affect the finished object to be printed, and in the worst case, the object to be printed may be damaged, so removing the sacrificial object is time-consuming and laborious. On the other hand, if the distance between the two is increased to prevent the sacrificial object from becoming integrated, the prevention of wobbling and tipping becomes weak. Therefore, a countermeasure is required that can prevent the object to be printed from wobbling and tipping without affecting the finished object to be printed.

Therefore, the present invention aims to provide a technology that prevents the object being shaped from wobbling or falling over.

In order to solve the above problems, the present invention provides the following program for generating data for three-dimensional modeling and a method for manufacturing a three-dimensional object. Note that the following words in parentheses are merely examples, and the present invention is not limited thereto.

In other words, the three-dimensional modeling data generation program of the present invention is a three-dimensional modeling data generation program that generates data used by a device that forms a three-dimensional object by stacking model materials, and causes a computer to execute a command generation step of generating data that commands the computer to form the shape of the three-dimensional object to be formed and the shape of a support that supports the three-dimensional object, the support having an internal through passage with an entrance facing upward and an exit facing the three-dimensional object at a lower position than the entrance, along a determined path for each layer that is divided into a plurality of layers, and to pour a predetermined amount of model material into the through passage after forming the layer that forms the entrance.

When modeling is performed according to data generated by this type of three-dimensional modeling data generation program, after the layer that forms the entrance to the through passage (the layer that includes the upper end of the through passage) is modeled, a predetermined amount of model material is poured into the through passage, so that the model material mostly fills the through passage and then overflows from the exit and adheres to part of the three-dimensional object, cooling and solidifying over time. Here, the layer to which the model material is attached is modeled at roughly the same time as the layer that forms the exit of the through passage, and therefore is cooled when the model material is poured into the through passage, so even if the attached model material solidifies, it is difficult for it to become integrated with these layers that form the three-dimensional object.

Therefore, according to this aspect of the 3D modeling data generation program, the 3D object can be supported on a support connected via the model material protruding from the outlet during modeling, preventing the 3D object from wobbling or tipping over, and after modeling, the support can be easily removed from the 3D object.

Preferably, in the data generation program for three-dimensional modeling of the above aspect, the following steps are executed prior to the command generation step: a support shape determination step for determining the shape and position of the support based on the shape of the three-dimensional object; a temperature prediction step for calculating the time required to model each layer obtained by dividing the shape of the three-dimensional object and the shape of the support into a plurality of layers and predicting the temperature drop of each layer during modeling; and a through passage shape determination step for determining the shape of the through passage based on the prediction result in the temperature prediction step so that the temperature difference between the layer forming the entrance and the layer forming the exit at the time when the model material is poured into the through passage is equal to or greater than a predetermined threshold value.

According to this aspect of the program for generating data for three-dimensional modeling, the shape of the through passage is determined based on the predicted temperature drop of each layer during modeling, so that the temperature difference between the layer forming the inlet and the layer forming the outlet at the time the model material is poured in is equal to or greater than a predetermined threshold. During modeling, the layer of the three-dimensional object at the same height as the layer forming the outlet of the through passage cools sufficiently before the model material is poured in. This reliably prevents the model material poured into the through passage from integrating with the three-dimensional object to which it is attached, and makes it possible to easily remove the support after modeling.

More preferably, in the three-dimensional modeling data generation program of the above aspect, in the through passage shape determination step, the above-mentioned predetermined amount is determined based on the shape of the through passage.

If there is not enough model material poured into the passage, the model material that protrudes from the exit cannot be sufficiently attached to the three-dimensional object, and there is a risk that the support body will not adequately support the three-dimensional object. On the other hand, if there is too much model material, a more than necessary amount of model material will adhere to the three-dimensional object, causing the support body to apply unnecessary force to the three-dimensional object, which may affect subsequent modeling. In contrast, with this type of three-dimensional modeling data generation program, the amount of model material to be poured into the passage is determined based on the shape of the passage, so that an appropriate amount of model material, neither too much nor too little, can be poured into the passage, and as a result, the support body can stably support the three-dimensional object.

More preferably, in the three-dimensional modeling data generation program of any of the above aspects, in the through passage shape determination step, the position of the through passage in the support is determined taking into account factors that affect the stable standing of the three-dimensional object.

According to this aspect of the 3D modeling data generation program, the position of the through passage is determined based on factors that affect the stable standing of the solid (e.g., the position of the center of gravity of the solid), so by supporting the solid on a support body having such a through passage, the standing of the solid can be made more stable and wobbling and tipping can be more effectively prevented.

The present invention makes it possible to prevent the object to be molded from wobbling or falling over.

FIG. 1 is a diagram illustrating an example of an environment in which a three-dimensional modeling apparatus operates. FIG. 2 is a diagram illustrating an example of an environment in which a three-dimensional modeling data generation program runs. 11 is a schematic diagram showing a method of managing positions in a three-dimensional modeling apparatus. FIG. FIG. 13 is a diagram showing the state immediately after a tensile test piece is modeled using data generated by a 3D modeling data generation program. FIG. 2 is a functional block diagram showing an example of the configuration of a three-dimensional modeling data generation program. 11 is a flowchart showing an example of a procedure for a three-dimensional modeling data generation process. 11 is a flowchart showing an example of a procedure for a layer-modeling data generation process. 10A and 10B are diagrams illustrating through passages formed inside a support body. 13A and 13B are diagrams showing modified examples of the shape of the through passage. FIG. 13 is a diagram explaining how to use the upper end of the through passage in a countersunk shape. FIG. 13 is a diagram showing an example in which a through passage is formed inside a general support region. 1A to 1C are diagrams showing various examples of the positions and numbers of supports to be installed on a shaped object. 13A to 13C are diagrams showing modified examples of the positions of through passages formed in the support body. 13A to 13C are diagrams illustrating further examples of use of the support body.

The following describes an embodiment of the present invention with reference to the drawings. Note that the following embodiment is a preferred example, and the present invention is not limited to this example.

[Operating environment of 3D modeling device]
FIG. 1 is a diagram showing an example of an environment in which a 3D modeling apparatus 40 operates, which models a 3D object using 3D modeling data generated by a 3D modeling data generation program according to an embodiment.

The terminal 10 is a computer that uses the 3D modeling device 40 and has a 3D modeling data generation program implemented therein. The 3D modeling device 40 is connected to the printer server 30 via a USB port, a serial port, etc., and is capable of sending and receiving data to and from the printer server 30. The printer server 30 is a computer that manages/controls print jobs for the 3D modeling device 40, similar to a typical printer server, and is connected to a wired or wireless network 20. When modeling a three-dimensional object, the terminal 10 transmits 3D modeling data used for modeling together with a print request (modeling request) to the printer server 30 via the network 20.

When the printer server 30 receives a print request from the terminal 10, it inserts it into the queue as one print job and receives the 3D modeling data. When the print job is started by the 3D modeling device 40, the printer server 30 transmits the 3D modeling data to the 3D modeling device 40 in small amounts. At this time, the amount of data transmitted to the 3D modeling device 40 is appropriately adjusted by a control program implemented inside the printer server 30. When all the 3D modeling data for one print job has been sent to the 3D modeling device 40 and the 3D modeling device 40 has completed its operations using this data, the 3D modeling device 40 ends printing (modeling).

In FIG. 1, the configuration is described as an example in which the terminal 10 uses the 3D modeling device 40 via the printer server 30. However, it is also possible to connect the 3D modeling device 40 directly to the terminal 10 without using the printer server 30, or to insert a storage medium such as a USB memory or an SD card that stores data for 3D modeling and use the 3D modeling device 40 independently (disconnected from the terminal 10).

[Operating environment for the 3D modeling data generation program]
2 is a diagram showing an example of an environment in which the 3D modeling data generation program according to an embodiment operates. The 3D modeling data generation program is installed in the terminal 10 as described above.

The terminal 10 is a computer equipped with the functions of a general computer, and includes, as hardware, a CPU 11, a RAM 12, a network interface (I/F) 13, a HDD 14, an input device 15 such as a mouse, a keyboard or a touch panel, and a display device 16 such as a liquid crystal display. As software, the terminal 10 is installed with 3D modeling software 17 that outputs polygon data (e.g., data in STL format) consisting of a collection of polygons that represent a three-dimensional shape, a three-dimensional modeling data generation software 100 that generates three-dimensional modeling data based on the polygon data output from the 3D modeling software 17, a printer driver 18 that is necessary for the terminal 10 to use the three-dimensional modeling device 40, and the like. Here, the three-dimensional modeling data generation software 100 is a so-called "slicer (slicing software)" and is implemented by a three-dimensional modeling data generation program of one embodiment.

When the polygon data output by the 3D modeling software 17 is input to the 3D modeling data generation software 100, the 3D modeling data generation software 100 repeatedly slices (horizontally cuts) the 3D shape formed by the polygon data into flat plates in the stacking direction (height direction), determines the path for forming each layer resulting from this, and generates command data one after another for discharging material along the determined path. Then, when the command data for forming all layers that make up the 3D shape are generated, the 3D modeling data generation software 100 outputs a collection of these command data as 3D modeling data (for example, data in G-Code format). When forming a 3D shape, the terminal 10 transmits a print request and 3D modeling data to the printer server 30 via the printer driver 18 and the network interface 13.

Note that in FIG. 2, an example of a configuration in which 3D modeling software 17 is installed on the terminal 10 that uses the 3D modeling device 40 has been described, but the 3D modeling software 17 does not necessarily have to be installed on the terminal 10, and it is sufficient if the configuration allows polygon data to be input to the 3D modeling data generation software 100. In addition, the terminal 10 may be equipped with other software, external devices, etc. as necessary.

As described above, the 3D modeling data generation software 100 is in essence a 3D modeling data generation program of one embodiment, so in the following description, the 3D modeling data generation software 100 will be referred to as the 3D modeling data generation program 100.

Figure 3 is a schematic diagram showing a method for managing positions in the three-dimensional modeling device 40.

The three-dimensional modeling device 40 has the components necessary to model a three-dimensional object in the internal space of the housing 41. First, a flat modeling table 42 is provided at the bottom of the internal space. Material MM is dispensed onto the modeling table 42, and multiple layers that make up the three-dimensional object are formed in order from the bottom up, with the upper layers being stacked on top of the lower layers in succession to form the three-dimensional object OB.

The material MM is discharged downward from the discharge nozzle 44. Before being supplied to the discharge nozzle 44, the material MM is in the form of a solid filament in the form of a string, but is heated to a high temperature by a heater installed inside the discharge nozzle 44, melted, and discharged in a fluidized state before being discharged from the discharge nozzle 44. The discharge nozzle 44 is supported by the support arm 43, and is configured to be movable within the internal space as the support arm 43 moves in the horizontal direction (X-axis and Y-axis directions in the figure) and the height direction (Z-axis direction in the figure). Note that the support arm 43 may be configured to be movable only in the horizontal direction, and the modeling table 42 may be configured to be movable in the height direction. Alternatively, the modeling table 42 may be configured to be movable in the horizontal direction as well, and the discharge position of the material MM may be changed by moving the modeling table 42 and the support arm 43.

The position in the internal space is managed by three-dimensional coordinates. The 3D modeling data used in modeling lists a large number of commands required for drawing the lines that discharge the material MM to form (fill in) each layer, specifically, commands that specify the coordinates of the destination and movement speed of the discharge nozzle 44, the amount of material MM discharged, the discharge pressure, and the discharge temperature. In FIG. 3, the modeling table 42 is shown with grid lines to make it easier to visualize the coordinates, but the actual modeling table 42 does not have such lines. In addition, the 3D modeling device 40 may be of a type in which the discharge nozzle 44 is supported by three movable parts of a pair of axes arranged in a delta shape (a so-called "delta type 3D printer").

[Shape of the three-dimensional object]
4 is a diagram showing a state immediately after a tensile test piece is modeled using data generated by the three-dimensional modeling data generation program 100. Note that in order to facilitate understanding of the invention, the objects shown in the drawings are exaggerated in size in the subsequent drawings, and the shapes and sizes of the objects, the sizes of the gaps between the objects, the size ratios between the objects and the gaps, and the like do not necessarily correspond to the actual ones.

Figure 4 (A): A perspective view showing the state of a three-dimensional object OB immediately after it is formed. The three-dimensional object OB shown in the figure is a dumbbell-shaped tensile test piece defined in the ASTM D638 standard, and is formed by layering material in the tensile direction of the test piece. In addition, two supports SP are formed at positions slightly away from the three-dimensional object OB, sandwiching it from both sides in the thickness direction. In the figure, part of the three-dimensional object OB is hidden by the supports SP, so the overall shape cannot be confirmed, but the three-dimensional object OB has a shape that is symmetrical from top to bottom, and the wide parts at the upper and lower ends correspond to the parts that are gripped in the tensile test.

Figure 4 (B): Plan view showing the state of the three-dimensional object OB immediately after it is formed. The three-dimensional object OB and the support body SP are formed together, and inside each support body SP, one or more through passages TH are formed, with the entrance facing upward and the exit facing sideways. The exit of the through passage TH is provided on the surface facing the three-dimensional object OB, and when the layer forming the entrance of the through passage TH, i.e., the layer including the upper end of the through passage TH (hereinafter sometimes referred to as the "upstream layer of the through passage"), is formed, the material MM is poured into the through passage TH, and the material MM overflows from the exit and adheres to the side of the three-dimensional object OB. The three-dimensional object OB is supported from the side by the support body SP connected through this part, which increases the stability of the upright object and reduces wobbling and tipping over.

Here, the layer with the entrance of the through passage TH is modeled after the layer with the exit, so when the material MM is poured into the through passage TH, a temperature difference occurs between the layer with the entrance and the layer with the exit, and the material MM poured from the through passage does not easily become integrated with the three-dimensional object OB. Therefore, after modeling, the support body OB can be easily removed from the three-dimensional object. When the two supports SP are removed from the three-dimensional object OB in the illustrated state, the three-dimensional object OB is completed.

In this way, by forming a support body SP having a through passage TH as described above together with the three-dimensional object OB (together, simultaneously), it is possible to achieve both reliable support of the three-dimensional object OB by the support body SP during the formation and easy removal of the support body SP after formation.

Next, we will explain the configuration and main processing of the 3D modeling data generation program 100, which generates data for such modeling.

[Configuration of the program for generating data for 3D modeling]
5 is a functional block diagram showing an example of the configuration of the 3D modeling data generation program 100. The 3D modeling data generation program 100 includes, for example, a various setting unit 110, a 3D shape input unit 120, a 3D shape analysis unit 130, a support shape determination unit 140, a shape cutting unit 150, a temperature prediction unit 160, a cross-sectional shape analysis unit 170, a path determination unit 180, and a generated data output unit 190.

The various setting unit 110 presets various thresholds and parameter values (e.g., the range of width (thickness, amount of material discharged), various temperatures (temperature inside the chamber, temperature of the modeling table 42, internal temperature of the discharge nozzle 44), patterns of shapes to be drawn, etc.) required for the 3D modeling data generation program to function. The various setting unit 110 also provides a setting screen for the user, and stores the contents set by the user via the setting screen in the internal memory area (HDD 14) of the terminal 10.

The three-dimensional shape input unit 120 inputs polygon data that forms a three-dimensional shape. More specifically, the three-dimensional shape input unit 120 reads polygon data output by 3D modeling software such as 3D-CAD. The polygon data is stored in a storage area accessible from the terminal 10 (for example, the HDD 14 or a separately connected external storage medium, etc.).

The three-dimensional shape analysis unit 130 analyzes the shape of a three-dimensional object formed by the polygon data input to the three-dimensional shape input unit 120.

Based on the analysis results by the three-dimensional shape analysis unit 130, the support shape determination unit 140 determines the shape and position of the support to be formed to support the three-dimensional object to be formed, and the shape, position, number, etc. of the through passages to be formed inside the support. In addition, the support shape determination unit 140 receives feedback from the temperature prediction unit 160 (described later) and adjusts the shape, etc. of the through passages as necessary.

The shape cutting unit 150 cuts the overall three-dimensional shape, which is a combination of the shape of the three-dimensional object formed by the polygon data input to the three-dimensional shape input unit 120 and the shape of the support body determined by the support shape determination unit 140, into multiple flat plate shapes (horizontally at multiple positions of different heights) and divides it into multiple layers stacked in the stacking direction (height direction).

The temperature prediction unit 160 estimates the molding time of each layer that includes a through passage (constitutes a through passage) from the shapes of each of the multiple layers divided by the shape cutting unit 150, and predicts the temperature drop of each layer over time. More specifically, the temperature prediction unit 160 predicts the temperature difference between the layer that forms the exit of the through passage during molding of the most upstream layer of the through passage (hereinafter referred to as the "most downstream layer of the through passage") based on the estimated molding time and various temperatures related to molding, determines whether the predicted temperature difference is sufficient, and feeds back the result to the support shape determination unit 140.

The cross-sectional shape analysis unit 170 analyzes the shape of each cross section cut by the shape cutting unit 150, in other words, the shape of each layer of the divided three-dimensional object and support.

Based on the results of the analysis by the cross-sectional shape analysis unit 170, the path determination unit 180 determines the path for discharging the material to form each layer, the order, direction, and speed of following the path, the width and amount of material to be discharged, and other details regarding the path (hereinafter, these are collectively referred to as "paths"), and generates command data according to the determined path. The path determination unit 180 also generates command data to pour material into the through passage after the uppermost layer of the through passage has been formed.

The generated data output unit 190 outputs a collection of command data generated by the path determination unit 180, i.e., data for three-dimensional modeling.

In the above example, the temperature prediction unit 160 estimates the modeling time for each layer that includes the through passage. Alternatively, the path determination unit 180 may more accurately calculate the modeling time for each layer, and based on this, the temperature prediction unit 160 may predict the temperature difference between the most upstream layer of the through passage and the most downstream layer of the through passage when modeling the most upstream layer of the through passage. In such a configuration, when the support shape determination unit 140 adjusts the shape of the through passage according to the predicted temperature difference, the path determination unit 180 must re-determine (correct) the path of the layer that includes the through passage. However, it is possible to more accurately predict the temperature difference between the most upstream layer and the most downstream layer of the through passage when modeling the most upstream layer of the through passage, and more reliably prevent the material poured into the through passage from being integrated with the three-dimensional object.

[3D modeling data generation process]
6 is a flowchart showing an example of a procedure of the 3D modeling data generation process. The 3D modeling data generation process is a process for generating 3D modeling data required when forming a 3D object using the 3D modeling device 40.

The steps shown in the flowchart are executed by the 3D modeling data generation program 100, but the main body that operates the 3D modeling data generation program 100 is the CPU 11 of the terminal 10, and strictly speaking, the CPU 11 causes each of the functional units 110 to 190 that make up the 3D modeling data generation program 100 to execute each step. An example procedure will be described below.

Step S10: The CPU 11 causes the three-dimensional shape input unit 120 to execute a three-dimensional shape input process. In this process, the three-dimensional shape input unit 120 reads polygon data that forms the shape of the three-dimensional object to be modeled.

Step S20: The CPU 11 causes the three-dimensional shape analysis unit 130 to execute a three-dimensional shape analysis process. In this process, the three-dimensional shape analysis unit 130 analyzes the shape of the three-dimensional object formed by the polygon data loaded in step S10, and determines factors that may affect the stable standing of the three-dimensional object (for example, the position of the center of gravity of the three-dimensional object, the position of the center of gravity of a protruding part, or the position of the center of the volume of the three-dimensional object, etc.).

Step S30: The CPU 11 causes the support shape determination unit 140 to execute a support shape determination process. In this process, the support shape determination unit 140 determines the shape and position of the support, the shape of the through passage to be formed inside the support and the elevation difference of its entrance and exit, the volume (amount) of material to be poured into the through passage, the number of through passages to be formed and their positions in the height direction, etc., based on the elements determined in step S20. The amount of material to be poured into the through passage is determined to be a necessary and sufficient amount to connect the three-dimensional object and the support, based on the volume of the through passage as well as the size of the gap between the exit of the through passage and the three-dimensional object facing it.

In step S30, the support shape determination unit 140 may select and apply one of a number of pre-patterned through-path shapes as the shape of the through-path to be formed inside the support. In this case, the volume of material poured into the through-path is a fixed amount according to the selected pattern.

Step S40: The CPU 11 causes the shape cutting unit 150 to execute a shape cutting process. In this process, the shape cutting unit 150 repeats the process of cutting the overall three-dimensional shape, which is a combination of the shape of the three-dimensional object formed by the polygon data read in step S10 and the shape of the support body determined in step S30, into a flat plate (horizontally) in the stacking direction (height direction).

Step S50: The CPU 11 causes the temperature prediction unit 160 and the support shape determination unit 140 to execute a through passage shape adjustment process. In this process, the temperature prediction unit 160 first estimates the modeling time for each layer containing a through passage from the shape of each layer generated by cutting in step S40, and then predicts the extent to which the temperature of the downstream layer of the through passage will drop when the upstream layer of the through passage is modeled (the temperature difference between the downstream layer and the upstream layer of the through passage) based on the internal temperature of the three-dimensional modeling device 40 and the internal temperature of the discharge nozzle 44 (the temperature of the heater that warms the material), and then compares the predicted temperature difference with a preset threshold value for the temperature difference to determine whether the temperature difference is sufficient, and feeds back the result to the support shape determination unit 140.

Next, if the temperature prediction unit 160 determines that the temperature difference is insufficient, i.e., if it is determined that the downstream layer of the through passage is not sufficiently cooled when the upstream layer of the through passage is being modeled, the support shape determination unit 140 adjusts the shape of the through passage (particularly the height (number of layers) between the upstream and downstream layers of the through passage), etc., and adjusts other parameters related to the through passage accordingly (e.g., the volume of material to be poured, etc.). By making such adjustments, it becomes possible to pour material into a through passage whose downstream layer has been sufficiently cooled during modeling.

Step S60: The CPU 11 causes the cross-sectional shape analysis unit 170 to update the layer to be processed. Specifically, the cross-sectional shape analysis unit 170 sets the multiple layers resulting from cutting the three-dimensional shape in step S40, one by one from the bottom up, as the target for subsequent processing (step S70). Therefore, when step S60 is executed for the first time, the bottommost layer of the three-dimensional shape is set as the target for processing.

Step S70: The CPU 11 causes the cross-sectional shape analysis unit 170 and the path determination unit 180 to execute a layer modeling data generation process. In this process, the cross-sectional shape analysis unit 170 analyzes the shape of the layer set as the target in step S60 (hereinafter referred to as the "target layer"), and the path determination unit 180 generates command data optimized for modeling the target layer. Details of the layer modeling data generation process will be described further below using another drawing.

Step S80: The CPU 11 causes the cross-sectional shape analysis unit 170 to check whether any unprocessed layers remain, i.e., whether any layers have not yet been subjected to the layer modeling data generation process (step S70). If any unprocessed layers remain (step S80: Yes), the CPU 11 returns to step S60 and repeats the subsequent steps. On the other hand, if no unprocessed layers remain (step S80: No), the CPU 11 proceeds to step S90.

Step S90: The CPU 11 causes the generated data output unit 190 to execute a generated data output process. In this process, the generated data output unit 190 outputs, as data for 3D modeling, a collection of command data generated by executing step S70 for all layers that make up the 3D shape.

When the above steps are completed, the CPU 11 ends the generation of data for the three-dimensional modeling of the three-dimensional object to be modeled and the support that supports it.

Note that the above procedure is merely an example and is not limited to this. For example, in the above procedure, in addition to the shape and position of the support, the support shape determination process (step S30) also determines the through passage to be formed inside the support, and the through passage shape adjustment process (step S50) predicts the temperature difference between the most upstream and most downstream layers of the through passage based on the shape of each layer cut in the shape cutting process (step S40) and adjusts the shape of the through passage as necessary. Alternatively, the shape of the through passage may not be determined in the support shape determination process (step S30), and the through passage shape adjustment process (step S50) may determine the shape of the through passage so that the lower part of the through passage is located in a sufficiently cooled position based on the temperature prediction result.

[Data generation process for layered modeling]
7 is a flowchart showing an example of the procedure of the layer-modeling data generation process. The layer-modeling data generation process is executed during the 3D modeling data generation process (step S70 in FIG. 6). The procedure will be described below along with the example.

Step S71: The CPU 11 causes the cross-sectional shape analysis unit 170 to analyze the cross-sectional shape. More specifically, the cross-sectional shape analysis unit 170 analyzes the shapes of the three-dimensional object and the support in the target layer.

Step S72: The CPU 11 causes the path determination unit 180 to determine a path. More specifically, the path determination unit 180 determines the path for forming the target layer, i.e., the path (the movement path of the discharge nozzle 44), the amount of material discharged on that path (layer pitch), the movement speed, the order in which lines are drawn along the path (the order in which the discharge nozzle 44 moves along each path), etc., based on the shape of the target layer analyzed in step S71.

For layers that include through passages, the path may be determined so that the filling rate of the lines that form the through passages and their surroundings is 100%, while the filling rate of the other lines is reduced (for example, the lines are drawn in a crisscross pattern, leaving some gaps). This ensures that the area around the through passage is completely filled with material during modeling, leaving no gaps, and it is possible to prevent the material poured into the through passage from leaking out through the gaps. Also, for each layer that includes through passages, the path may be determined so that the lines that form the through passages are drawn before the other lines. This makes it possible to reduce the temperature of the material that forms the through passages more quickly during modeling.

Step S73: The CPU 11 causes the path determination unit 180 to check whether the target layer corresponds to the most upstream layer of the through passage formed inside the support. If the target layer corresponds to the most upstream layer of the through passage (step S73: Yes), the CPU 11 proceeds to step S74. On the other hand, if the target layer does not correspond to the most upstream layer of the through passage (step S73: No), the CPU 11 proceeds to S75.

Step S74: The CPU 11 adds a command to pour material into the through passage after completing the modeling of the most upstream layer of the through passage. In this command, the volume of material to be poured into the through passage is the volume determined in advance by the support shape determination unit 140, specifically, the volume determined or adjusted in steps S30 and 50 in FIG. 6.

Step S75: The CPU 11 causes the path determination unit 180 to execute a command data generation process. In this process, the path determination unit 180 generates command data corresponding to the path determined in step S72 and the command added in step S74.

When the above steps are completed, the CPU 11 ends the generation of command data for one layer (target layer). This procedure is then repeated for all layers.

[Design of the passageway]
FIG. 8 is a diagram illustrating the through passage TH formed inside the support body SP.

8A: A vertical cross-sectional view showing the shape of the through passage TH in the extension direction (cross-sectional view taken along VIII _A -VIII _A in FIG. 4). Inside the support SP, a through passage TH is formed that penetrates in a substantially L-shape from an inlet HI facing upward to an outlet HO facing sideways. The overall height L _T of the L-shaped through passage TH is set to, for example, about 2 to 2.5 times (2 times in the illustrated example) the height L _H of the outlet HO. The height L _T of the through passage TH is not limited to this, and may be variously different dimensions depending on the shape of the through passage TH.

FIG. 8B: A vertical cross-sectional view (cross-sectional view taken along VIII _B -VIII _B in FIG. 4) showing the radial shape of the through passage TH (hereinafter referred to as the "cross-sectional shape"). For example, when the cross-sectional shape of the through passage TH is substantially circular as shown in FIG. 4B, the cross-sectional shape is formed to be substantially circular by gradually shifting the drawn line from the line drawn in the layer immediately below or gradually overhanging it at an inclination of 45 degrees or less when forming the layer including the through passage. In the illustrated example, the through passage is formed at a layer pitch of 0.1 mm using a discharge nozzle with a substantially circular cross section and an inner diameter of 0.4 mm. The height _LH of the cross section of the through passage TH, i.e., the height _LH of the outlet HO, and the width _LW of the cross section are set to, for example, about 0.4 to 0.6 mm.

The cross-sectional shape and thickness of the through passage TH do not need to be constant, and may vary depending on the position of the through passage TH. In addition, the cross-sectional shape of the through passage TH is not limited to being approximately circular, and can be changed as appropriate depending on the situation, for example, to be approximately rectangular, approximately triangular, approximately elliptical, etc.

8C: The three-dimensional object OB to be molded, the support SP for supporting it, and the discharge nozzle 44 are cut in the same direction as in FIG. 8A, and the material MM is poured into the through passage TH. The distance _LS between the three-dimensional object OB and the support SP is set to a value (e.g., about 0.3 mm) that exceeds the dimensional error that may occur during molding by the FFF method.

The three-dimensional object OB and the support body SP are molded together, and when the molding of the most upstream layer LT, which includes the upper end of the through passage TH formed inside the support body SP, is completed, the nozzle 44 moves so that the nozzle hole 46 is aligned with the center of the inlet HI while blocking the inlet HI with its tip. Then, the material MM is forcefully ejected from the nozzle hole 46 with the internal pressure higher than when the layer was molded, so that the material MM fills the through passage TH mostly, then overflows from the outlet HO, and adheres to the side of the three-dimensional object OB while connected to the through passage TH, where it cools and solidifies over time.

At this time, the layer of the three-dimensional object OB to which the material MM is attached is formed at roughly the same time as the layer forming the lower part of the through passage TH, and therefore is already sufficiently cooled by the time the material MM is poured into the through passage TH, so that the attached material MM does not easily become integrated with these layers of the three-dimensional object OB even when it solidifies. Therefore, during modeling, the support body SP can support the three-dimensional object OB and prevent it from wobbling or tipping over, and after modeling, the support body SP can be easily removed from the three-dimensional object OB.

FIG. 9 is a diagram showing various modified examples of the shape of the through passage TH.
Although the through passage TH described above has a substantially L-shape in the extension direction, the shape of the through passage TH is not limited to this. The through passage TH only needs to have at least an inlet for the material MM at a position higher than an outlet, and an outlet at a position facing the three-dimensional object.

For example, as shown in FIG. 9A, the bent portion of the through passage TH may be formed to be inclined instead of right-angled, or as shown in FIG. 9B, the through passage TH may be formed to be linearly penetrating from above to the side. Also, as shown in FIG. 9C, when the three-dimensional object OB has a shape that inclines downward, the support body SP may be formed to be inclined upward so as to face it, and a roughly J-shaped through passage TH may be formed inside it, and the material MM may be applied to the side of the three-dimensional object OB from below. Although not shown in the figure, the through passage TH may be branched into two or more branches along the way. In addition, in any shape of the through passage TH, the cross-sectional shape (thickness) may not be constant.

FIG. 10 is a diagram for explaining a method of using the through passage TH when the upper end portion thereof is formed in a countersunk shape.
10A, when a countersink CB is formed at the upper end of the through passage TH, the material MM is poured into the through passage TH after the modeling of the layer including the countersink CB is completed. By forming the through passage TH in this manner, the internal pressure of the discharge nozzle 44 can be adjusted using the countersink CB during modeling.

Specifically, first, as shown in FIG. 10B, with the tip of the discharge nozzle 44 blocking the inlet HI, the internal pressure is increased from that during the formation of the layer and the material MM is forcefully discharged from the discharge hole 46, filling the through passage TH with the material MM. After that, the discharge nozzle 44 is moved slightly upward, and as shown in FIG. 10C, the material MM is discharged while decreasing the internal pressure so as to fill the countersunk hole CB, making it possible to return the internal pressure of the discharge nozzle 44 to an internal pressure suitable for forming the layer before starting to form the next layer.

Figure 11 shows an example in which a support SP is a so-called general support area that serves as a base for supporting a part suspended in air when modeling the part, and a through passage TH is formed inside such a support SP. For visibility, the three-dimensional object OB is shown shaded in Figure 11.

For example, as shown in FIG. 11 (A), when forming a three-dimensional object OB having an arm-like portion extending to the right from the middle of a columnar portion extending upward, in other words a roughly U-shaped object, a support body SP is usually formed to support the arm-like portion from below. In such a support body SP, as shown in FIG. 11 (B), a through passage TH is formed inside, and after forming the uppermost layer LT including the upper end of the through passage TH, material MM is poured into the through passage TH, so that the material MM overflows from the outlet of the through passage TH and adheres to the side of the columnar portion of the three-dimensional object OB and solidifies. This allows the support body SP to support the columnar portion extending upward from the side while the columnar portion is being formed, stabilizing the standing of the portion and preventing it from wobbling or falling over.

Figure 12 shows various examples of the positions and number of supports SP to be installed on a three-dimensional object OB. Of these, (A-1), (B-1), and (C-1) are perspective views showing examples of the shape of a three-dimensional object OB, and (A-2), (B-2), and (C-2) are plan views showing the state of the three-dimensional object OB shown immediately before immediately after it has been formed.

In the example of Figure 4 described above, since the three-dimensional object OB is a thin plate-like test piece that is long in the stacking direction, two supports SP are placed to sandwich it from both sides in the thickness direction so that it can be stably supported. In contrast, if the three-dimensional object OB has an axisymmetric shape as shown in (A-1) in Figure 12, for example, as shown in (A-2) in Figure 12, the supports SP can be placed one by one at positions that are three-fold symmetric about the central axis, and the three-dimensional object OB can be supported from three directions. Note that this is not limited to three-fold symmetry, and the supports SP can be placed one by one at positions that are rotationally symmetric about the central axis.

As shown in FIG. 12 (B-1), if the three-dimensional object OB is a rectangular parallelepiped extending upward, then, for example, as shown in FIG. 12 (B-2), supports SP can be installed at positions facing each of the four sides to support the three-dimensional object OB from four directions. Also, as shown in FIG. 12 (C-1), for example, if the three-dimensional object OB has a stable shape at the bottom but has a part at the top that extends high on only one side, and the shape of this part may cause the center of gravity to shift to one side, making it unstable to stand up, then, as shown in FIG. 12 (C-2), supports SP can be installed at positions facing the part that causes this to happen, to support this part, thereby preventing the three-dimensional object OB from wobbling or falling over.

Figure 13 shows modified positions of the through passage TH (exit HO) formed inside the support body SP. As described above, one or more through passages TH are formed inside the support body SP, and the exits HO are provided on the surface of the support body SP facing the three-dimensional object OB (hereinafter referred to as the "facing surface"). However, the formation position of the through passage TH, and thus the installation position of the exit HO, can be modified in various ways.

For example, as shown in FIG. 13A, multiple through passages TH may be formed at positions that are approximately equally spaced in the height direction along the approximate center of the width direction on the opposing surface. Also, as shown in FIG. 13B, two through passages TH may be formed at the same height on the opposing surface, one through passage TH may be formed at a position above this position at a predetermined distance, and two through passages TH may be formed at a position above this position at a predetermined distance, in this manner, the number of through passages TH may be alternatingly changed from 2 to 1 to 2 to 1 to ... at positions that are approximately equally spaced in the height direction. Alternatively, as shown in FIG. 13C, through passages TH may be formed one by one in a zigzag pattern at positions that are approximately equally spaced in the height direction on the opposing surface.

Although not shown in the figure, it is also possible to determine the formation position of the through passage TH based on the position of the center of gravity of the three-dimensional object OB. For example, the position of the center of gravity of the three-dimensional object OB alone is calculated, and the through passage TH is formed at a position below that height. During modeling, the three-dimensional object OB is supported by the support body SP via the material poured into the through passage TH. Therefore, when forming multiple through passages TH, next, the position of the center of gravity of the three-dimensional object OB in a state where it is supported using the first through passage TH is calculated, and the second through passage TH is formed at a position below that height. In this way, the position of the center of gravity of the three-dimensional object OB may be calculated, and one or more through passages TH may be formed at a position according to the result. Note that the position of the center of gravity of the three-dimensional object OB is calculated by the above-mentioned three-dimensional shape analysis unit 130, and the formation position of the through passage TH according to it is determined by the above-mentioned support shape determination unit 140.

[Application example of a support having a through passage]
FIG. 14 is a diagram for explaining a further example of use of the support SP.

In the examples described so far, a support SP with an internal through passage TH was installed to support a three-dimensional object OB with a shape that is prone to wobbling or tipping over, but a similar support SP can also be used when forming a three-dimensional object OB with a stable shape.

Figure 14 (A): A perspective view showing the state of a three-dimensional object OB immediately after it has been formed. The three-dimensional object OB shown in the figure has a wide and stable shape on the top and bottom, but it is assumed that after formation, it will be necessary to cut some of the wall on the back side to make it smooth. When forming such a three-dimensional object OB, a raft RA is first formed on the forming table 42, and then the three-dimensional object OB and an appropriate number of supports SP to support it are formed on the raft RA. The supports SP are provided at a position opposite the area to be cut, in the illustrated example, at a position facing the front of the three-dimensional object OB. Once formation is complete, the object is transferred to a cutting device together with the raft RA.

Figure 14 (B): Plan view showing the state in which the object has been transferred to the cutting device. The cutting device is not shown. The object is fixed to the cutting device via positioning holes PH provided at the four corners of the raft RA, and then a part of the wall CP on the back side is cut. At this time, the impact from the cutting is usually transmitted to the three-dimensional object OB, causing it to vibrate, which may cause the three-dimensional object OB to peel off from the raft RA, and in that case, there is a risk of damaging parts that are not to be cut. In contrast, if a support body SP is installed to support the three-dimensional object OB, the support of the support body SP can suppress the vibration of the three-dimensional object OB, and as a result, it is possible to prevent the three-dimensional object OB from peeling off from the raft RA.

The present invention is not limited to the above-described embodiment, and can be modified in various ways. The various numerical values given in the embodiment are merely examples, and the present invention is not limited to these numerical values.

In the above-described embodiment, a discharge nozzle 44 having a discharge hole 46 with a substantially circular cross section is used for the shaping, but the cross-sectional shape of the discharge hole 46 is not limited to a substantially circular shape. For example, it may be rectangular or rhombic.

10 Terminal 11 CPU
20 Network 30 Printer server 40 Three-dimensional modeling device 42 Modeling table 44 Discharge nozzle 46 Discharge hole 100 Three-dimensional modeling data generation program

Claims (8)

A three-dimensional modeling data generation program for generating data used by an apparatus for stacking model materials to form a three-dimensional object, comprising:
On the computer,
a command generating step of generating data for generating a three-dimensional modeling data generating program for executing a command generating step of generating data for generating a command to pour a predetermined amount of model material into the through passage after forming the layer forming the entrance, the command generating step generating data for generating a command to pour a predetermined amount of model material into the through passage, the amount being sufficient to connect the three-dimensional object and the support, the command generating step generating data for generating a command to pour a predetermined amount of model material into the through passage, the amount being sufficient to connect the three-dimensional object and the support, the command generating step generating data for generating a command to pour a predetermined amount of model material into the through passage, the command ... 2. The three-dimensional modeling data generation program according to claim 1,
a support shape determination step of determining a shape and a position of the support based on the shape of the solid body;
a temperature prediction step of calculating a time required for modeling each of a plurality of layers obtained by dividing the shape of the three-dimensional object and the shape of the support into the plurality of layers, and predicting a temperature decrease of each layer during modeling;
a through passage shape determination step of determining a shape of the through passage based on the prediction result in the temperature prediction step so that a temperature difference between the layer forming the inlet and the layer forming the outlet at the time when the model material is poured into the through passage is equal to or greater than a predetermined threshold value corresponding to a sufficient temperature difference set in advance ;
A program for generating data for three-dimensional modeling, the program being executed prior to the command generating step. 3. The three-dimensional modeling data generation program according to claim 2,
In the through passage shape determination step,
The predetermined amount is determined based on a shape of the through passage. 4. The three-dimensional modeling data generation program according to claim 2,
In the through passage shape determination step,
A data generation program for three-dimensional modeling, characterized in that a position of the through passage in the support is determined taking into account factors that affect the stable standing of the three-dimensional object. A method for manufacturing a three-dimensional object using an apparatus for forming a three-dimensional object by stacking model materials, comprising the steps of:
a command generation process for generating data for generating commands to generate data for generating a command to generate a command for generating data for generating a command ...
a modeling process for modeling the three-dimensional object and the support by causing the apparatus to model each of the layers according to the data;
and a removing step of removing the shaped support. The method for producing a three-dimensional object according to claim 5 ,
a support shape determination step of determining a shape and a position of the support based on the shape of the solid body;
a temperature prediction step of calculating a time required for modeling each of a plurality of layers obtained by dividing the shape of the three-dimensional object and the shape of the support into a plurality of layers, and predicting a temperature decrease of each layer during modeling;
a through passage shape determination process for determining a shape of the through passage based on a prediction result in the temperature prediction process so that a temperature difference between the layer forming the inlet and the layer forming the outlet at the time when the model material is poured into the through passage is equal to or greater than a predetermined threshold value corresponding to a sufficient temperature difference set in advance ;
The method for manufacturing a three-dimensional object further includes a step before the command generating step. The method for producing a three-dimensional object according to claim 6,
In the through passage shape determination process,
The method for manufacturing a three-dimensional object, comprising determining the predetermined amount based on a shape of the through passage. The method for producing a three-dimensional object according to claim 6 or 7,
In the through passage shape determination process,
A method for manufacturing a three-dimensional object, comprising determining a position of the through passage in the support, taking into account factors that affect the stable standing of the three-dimensional object.

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