JP2024157479A - MEASURING APPARATUS, MEASURING METHOD, THREE-DIMENSIONAL PRODUCTION SYSTEM, AND CONTROL METHOD - Google Patents

Abstract

A device for accurately measuring the position of a nozzle is provided.
[Solution] A measurement device (90) for a 3D printer (1) equipped with a nozzle (41) that ejects material includes a touch panel (91) that detects the vertical height of the tip of the nozzle, and a scanner (92) that detects the position of the tip in a horizontal plane.
[Selected Figure] Figure 1

Description

The present invention relates to a measurement device for a three-dimensional modeling device and a three-dimensional modeling system using the same.

3D printers (three-dimensional modeling devices) that use the fused deposition modeling method, in which a resin filament is heated and melted and ejected from a nozzle in the head, are widely used as devices for creating three-dimensional objects (solid objects). In fused deposition modeling 3D printers, it is common to slice the modeling data in a horizontal plane (horizontal slice) and then stack them vertically.

Here, in horizontal slicing, if there is no layer below the object, the ejected material will fall vertically downward. For this reason, if the model of the object to be printed is hollow, it is known that it is necessary to layer support material below the object.

In recent years, non-planar slicing, which slices and stacks on free-form surfaces rather than horizontal planes, has been attracting attention. With non-planar slicing, because it is possible to stack on free-form surfaces, it is possible to print without using support materials even for models that do not have a modeled object vertically below. For non-planar slicing, it is common to use a 5-axis 3D printer such as that shown in Non-Patent Document 1.

Freddie Hong, SteCe Hodges, Connor Myant, DaCid Boyle, Open5x: Accessible 5-axis 3D printing and conformal slicing, arXiC:2022.11426C2, TBe, 29 Mar 2022 16:06:20 BTC, https://arxiC.org/abs /2202.11426

In Non-Patent Document 1, in addition to the three axes of X/Y/Z, which are typical positions, two axes are added to rotate and tilt the object to control the attitude of the object. The mechanism compatible with non-planar slicing is not limited to the configuration in Non-Patent Document 1, and may be, for example, a six-axis parallel link mechanism.
However, when a six-axis parallel link mechanism is employed to control the attitude in addition to the position, it is difficult to control the nozzle that ejects the material to the desired position and attitude due to various factors.

The object of the present invention is to realize a device that can accurately measure the position of a nozzle.

To solve the above problems, a measurement device according to one embodiment of the present invention is a measurement device for a three-dimensional modeling device equipped with a nozzle that ejects material, and includes a tip height detection unit that detects the vertical height of the tip of the nozzle, and a horizontal position measurement unit that detects the position of the tip in a horizontal plane.

In order to solve the above problems, a measurement method according to one aspect of the present invention is a measurement method for a three-dimensional modeling device equipped with a nozzle that ejects material, and includes a tip height detection step for detecting the vertical height of the tip of the nozzle, and a horizontal position measurement step for measuring the position of the tip in a horizontal plane.

The above configuration makes it possible to measure the vertical height and horizontal position of the nozzle tip. This value can then be used to correct the position and orientation of the nozzle tip.

The horizontal position measurement unit may measure the position optically. With the above configuration, the position in the horizontal plane can be measured with high accuracy.

The tip height detection unit may detect contact of the tip with a specific plane. With the above configuration, the height on the specific plane can be measured, and correction can be made based on the height relative to this plane.

The tip height detection unit may be a touch panel or a touch switch, and the horizontal position measurement unit may be a scanner or a camera.

The device may further include a posture detection unit that measures the posture of the nozzle. With the above configuration, it is possible to measure the posture of the nozzle, and even correct the posture of the nozzle.

In order to solve the above problems, a three-dimensional printing system according to one aspect of the present invention is a three-dimensional printing system including the three-dimensional printing device and a measurement device, and includes a memory unit that stores the vertical height and the horizontal position of the nozzle at multiple command positions and command attitudes, a calculation unit that calculates a control command position and a control command attitude from the desired vertical height and the desired horizontal position based on the memory unit, and a control unit that controls the three-dimensional printing device to the control command position and the control command attitude.

In order to solve the above problems, a control method according to one aspect of the present invention is a control method for a three-dimensional printing system including the three-dimensional printing device and a measurement device, and includes a storage step of storing the vertical height and the horizontal position of the nozzle at a plurality of command positions and command attitudes, a calculation step of calculating a desired command position and command attitude from the desired vertical height and the desired horizontal position based on the storage unit, and a control step of controlling the three-dimensional printing device to the desired command position and command attitude.

According to the above configuration, by using a measuring device for the 3D printing device, the accuracy of the position and orientation of the 3D printing device can be improved.

According to one aspect of the present invention, it is possible to realize a device that can accurately measure the nozzle position.

FIG. 1 is a block diagram showing a configuration of a main part of a three-dimensional printing system according to an embodiment. FIG. 1 is a perspective view showing a configuration of a 3D printer according to an embodiment. FIG. 2 is a schematic diagram showing a certain attitude of a nozzle. 11A and 11B are schematic diagrams illustrating different attitudes of the nozzle. FIG. 13 is a schematic diagram showing yet another attitude of the nozzle. FIG. 1 is a top view of a 3D printer according to an embodiment. 11 is a flowchart showing a method for acquiring calibration data. FIG. 13 is a diagram showing positions in a horizontal plane where measurements were taken in the calibration data. FIG. 2 is a diagram showing positions in a horizontal plane acquired by a scanner. 13 is a flowchart showing a correction method performed by a calculation unit. 4 is an example of a projection relationship for calculating a control command position and a control command attitude.

[Embodiment]
Fig. 1 is a block diagram showing the configuration of the main parts of a three-dimensional modeling system 100 according to an embodiment. The three-dimensional modeling system 100 includes a 3D printer 1 (three-dimensional modeling device) and a measurement device 90. First, the configuration and operation method of the 3D printer 1, which is the target for measuring the position of the nozzle that ejects material in this embodiment, will be described with reference to Figs.

(Configuration of 3D printer 1)
2 is a perspective view showing the configuration of the 3D printer 1 according to embodiment 1. The 3D printer 1 includes a set of frames 10, six linear drive shafts 20, six first ball joints 30, one head 40, six second ball joints 50, six links 60, one modeling stage 70, and a control unit 80.

The frame 10 is a member that secures the main parts of the 3D printer 1. The frame 10 is mainly divided into an upper frame 11 and a lower frame 12.

The linear drive shaft 20 is an actuator that performs linear motion and connects the upper frame 11 and the lower frame 12. The linear drive shaft 20 can take any drive form, such as a linear motor, a ball screw, or a timing belt. In this embodiment, a stepping motor (not shown) and a timing belt (not shown) are used, but the type of motor used is not limited.

In the embodiment, the linear drive shaft 20 also functions as a frame that connects the upper frame 11 and the lower frame 12 and as a linear guide, but a separate vertical frame and linear guide may also be provided. The six linear drive shafts extend vertically and are installed parallel to one another. When distinguishing between the linear drive shafts 20, they are referred to as linear drive shafts 20a to 20f.

The first ball joint 30 is a ball joint driven by the linear drive shaft 20. The first ball joint 30 may be any mechanism that rotates and oscillates, for example a universal joint. When distinguishing between the first ball joints 30, they are referred to as first ball joints 30a to 30f. The linear drive shaft 20 drives the first ball joints 30 with the corresponding suffixes "a" to "f". In other words, the linear drive shaft 20a drives the first ball joint 30a.

The head 40 melts the material supplied from the extruder (not shown) and ejects it from the nozzle 41. In the 3D printer 1, the position and attitude of the tip 41a of the nozzle 41 is controlled by rotating and/or tilting the head 40.

The second ball joint 50 is a ball joint that is connected to the head 40. The second ball joint 50 may be any mechanism that rotates and swings, for example a universal joint. When distinguishing between the second ball joints 50, they are referred to as second ball joints 50a to 50f.

The link 60 is a link that connects the first ball joint 30 and the second ball joint 50. The link 60 extends along a straight line that passes through the center of oscillation of the first ball joint 30 and the center of oscillation of the second ball joint 50. The link 60 may also be a rod. When distinguishing between the links 60, they are referred to as links 60a to 60f. The links 60 connect the first ball joint 30 and the second ball joint 50 of the corresponding subscripts "a" to "f". In other words, the link 60a connects the first ball joint 30a and the second ball joint 50a. In addition, the lengths of the links 60a to 60f are all equal, that is, the distances from the first ball joint 30 to the second ball joint 50 are all equal.

The modeling stage 70 is a stage that stacks the material ejected from the nozzle 41 and holds the model. The modeling stage 70 may be heatable. The modeling stage 70 is fixed to the frame 10. The modeling stage 70 is also installed on a horizontal plane.

The control unit 80 controls the linear drive shaft 20 to place the head 40 and nozzle 41 in the desired position and/or posture. In addition, the load cell 42 detects when the nozzle 41 comes into contact with the modeling stage 70. In other words, the control unit 80 comprehensively controls each part of the 3D printer 1. Details will be described later.

(Definition of position and orientation of 3D printer 1)
The position and orientation of the head 40 can be defined by the position and orientation of the nozzle 41, which are the position Pn (xn, yn, zn) of the tip 41a of the nozzle 41 and the orientation (φ, θ) of the nozzle 41. The position (xn, yn, zn) has the center of the modeling stage 70 as its origin.

The attitude (φ, θ) can be defined as a direction vector that moves in accordance with the attitude of the nozzle 41, where φ is the angle between the direction vector and the Z axis, and θ is the angle of the X/Y components of the direction vector. In other words, φ is the tilt angle, and θ is the rotation angle.

For example, the orientation of the nozzle 41 when φ=0° is as shown in FIG. 3, which is perpendicular (vertical) to the modeling stage 70. The orientation of the nozzle 41 when θ=0° and φ>0° is as shown in FIG. 4. Moreover, the orientation of the nozzle 41 when θ≠0° and φ>0° is as shown in FIG. 5.

(Operation of 3D printer 1)
Next, the operation of the 3D printer 1 will be described. Fig. 6 is a top view of the 3D printer 1 according to the first embodiment. As shown in Fig. 6, it can be seen that the linear drive shafts 20 of the 3D printer 1 are arranged in pairs at each of the vertices of a substantially equilateral triangle. In other words, it can be seen that the first ball joints 30 each move linearly (vertically) in the vicinity of each of the vertices of the above-mentioned substantially equilateral triangle. As a result, the X/Y coordinates of the first ball joints 30 do not change, and only the Z coordinate changes.

The head 40 also has two second ball joints 50 arranged at each vertex of a roughly equilateral triangle that faces in the opposite direction to the roughly equilateral triangle described above. In other words, the second ball joints 50 are fixed relative to each other.

Since the distance between the first ball joint 30 and the second ball joint 50 is constant due to the link 60, the position of the second ball joint 50 can be controlled by controlling the position of the first ball joint 30 with the linear drive shaft 20, and as a result, the position and/or attitude of the head 40 and nozzle 41 can be controlled.

(Measuring Device 90)
The measuring device 90 includes a touch panel 91 (tip height detection unit), a scanner 92 (horizontal position measurement unit), and an acceleration sensor 93 (attitude detection unit). The measuring device 90 is not fixed to the 3D printer 1, and may be configured to be able to be placed on the 3D printer 1 when necessary. In this embodiment, the scanner 92 is placed on the modeling stage 70, and the touch panel 91 is further placed on top of the scanner 92. Also, the acceleration sensor 93 is fixed to the head 40.

(Touch panel 91)
The touch panel 91 is a resistive touch panel, and detects when the tip 41a of the nozzle 41 comes into contact with the touch panel 91. Furthermore, when the touch panel 91 detects the contact of the tip 41a of the nozzle 41 with the touch panel 91, it outputs a signal to the control unit 80 to notify the control unit 80 that the contact has been detected. Note that when the control unit 80 receives this signal, it ends the probe operation being performed (the operation of moving the nozzle vertically downward) and detects the vertical height at that point in time.

Note that the touch panel 91 is not limited to a touch panel, and may be a transparent touch switch or a laser-type area sensor. In other words, the touch panel 91 may be a sensor that detects when the vertical height of the tip 41a of the nozzle 41 reaches (comes into contact with) a specific plane.

(Scanner 92)
The scanner 92 is a device that acquires a two-dimensional image by moving a line camera in a direction perpendicular to the extension direction of the line camera, and is a so-called scanner. In this embodiment, the glass that is the top surface of the scanner 92 is a touch panel 91. The focal length of the scanner 92 generally matches the glass on the top surface. Therefore, the tip 41a of the nozzle 41 that comes into contact with the touch panel 91 matches the focal length of the scanner 92, and a good image can be acquired.

The scanner 92 outputs the acquired two-dimensional image to the control unit 80, and the control unit 80 processes the two-dimensional image and measures the position of the tip 41a of the nozzle 41. In addition, the image processing of the position of the tip 41a of the nozzle 41 may be performed by the control device of the scanner 92 instead of the control unit 80.

The scanner 92 is not limited to a scanner, and may be a camera that moves in a horizontal plane. In this case, the position of the tip 41a of the nozzle 41 is measured using the image of the camera in addition to the position of the camera. In other words, the scanner 92 may be a sensor that detects the position of the tip 41a of the nozzle 41 in the horizontal plane. For example, the position in the horizontal plane may be measured using the touch panel 91. However, from the standpoint of noise and resolution, it is preferable that the scanner 92 optically detects the position in the horizontal plane.

(Acceleration sensor 93)
The acceleration sensor 93 is an acceleration sensor that can detect acceleration in at least three or more axes. The acceleration sensor 93 outputs the detected acceleration to the control unit 80. From the direction of the gravitational acceleration detected by the acceleration sensor 93, the attitude of the head 40, i.e., the attitude of the nozzle 41, can be calculated.

The acceleration sensor 93 is not limited to an acceleration sensor, but may be any sensor that detects any posture, such as a gyro sensor or a system using multiple infrared markers.

(Control unit 80)
The control unit 80 includes an acquisition unit 81, a storage unit 82, a calculation unit 83, and a command unit 84. The acquisition unit 81 acquires the measurement results detected by the measuring device 90. The storage unit 82 stores the measurement results of the measuring device 90 acquired by the acquisition unit 81. The storage unit 82 also stores the conditions (command position and command attitude) under which the measurement was performed by the measuring device 90. These measurement results, command position, and command attitude are collectively referred to as calibration data.

The calculation unit 83 calculates the required control command position and control command attitude from the desired vertical height and the desired position and attitude in the horizontal plane based on multiple calibration data stored in the memory unit. In other words, the calculation unit 83 calculates the required correction values for the control command position and control command attitude from the desired position and attitude. The calculation unit 83 outputs the calculated desired control command position and control command attitude to the command unit 84.

The command unit 84 controls the linear drive shaft 20 so that it assumes the input position and attitude. In other words, the memory unit 82, calculation unit 83, and command unit 84 are used to back-calculate the control command position and control command attitude that result in the input position and attitude, and control is performed using these values, thereby controlling the position and attitude to the desired state.

(How to obtain calibration data)
The following describes a method for acquiring calibration data using the control unit 80 and the measuring device 90. Fig. 7 is a flowchart showing the method for acquiring calibration data.

The command unit 84 controls the 3D printer 1 to a position and posture for acquiring the calibration data. That is, the command unit 84 moves the nozzle 41 to a position in the horizontal plane where the measurement will be performed in the posture for performing the measurement (S11).

Then, the command unit 84 lowers the nozzle 41 vertically downward so that the vertical height decreases while maintaining the position and attitude in the horizontal plane (S12). The touch panel 91 determines whether the nozzle 41 has come into contact with the touch panel 91 (S13). If the nozzle 41 is not in contact with the touch panel 91, the process returns to S12, and the nozzle 41 continues to descend.

On the other hand, when the nozzle 41 touches the touch panel 91, the process transitions to S14. The touch panel 91 outputs a signal to the control unit 80 to stop the descent of the nozzle 41, and upon receiving this signal, the command unit 84 ends the descent of the nozzle 41 (S14). Here, a so-called probe operation is performed, and the vertical height of the tip 41a of the nozzle 41 is measured.

Then, while the tip 41a of the nozzle 41 is on the surface of the touch panel 91, the scanner 92 acquires a two-dimensional image (S15). The scanner 92 outputs the acquired two-dimensional image to the control unit 80, which processes the image and calculates the position of the tip 41a of the nozzle 41 in the horizontal plane (S16). Note that the device that performs the image processing is not limited to the control unit 80.

The memory unit 82 stores the acquired calibration data. That is, the vertical height when the tip 41a of the nozzle 41 contacts the touch panel 91, the position in the horizontal plane of the tip 41a of the nozzle 41 obtained by image processing, the position where the measurement was performed, and the attitude where the measurement was performed are all stored (S17).

The calibration data may also include the posture of the head 40 that can be measured by the acceleration sensor 93. In other words, the actual posture may be measured based on the posture at which the measurement was performed, and the memory unit 82 may also store this.

(Calibration data status)
Fig. 8 is a diagram showing positions in a horizontal plane where measurements were taken in the calibration data. Points in Fig. 8 represent positions in a horizontal plane where measurements were taken. Line segments connecting the points are also shown in Fig. 8. As will be described in detail later, the calculation unit 83 performs correction using a triangle defined by these three line segments.

Figure 9 is a diagram showing positions in a horizontal plane acquired by the scanner 92. Each point and triangle in Figure 9 corresponds one-to-one to each point and triangle in Figure 8. In other words, Figures 8 and 9 have a projection relationship that includes errors of the 3D printer 1. While the points are regularly arranged in Figure 8, the points are irregularly arranged in Figure 9. This difference is due to errors in the 3D printer 1.

The causes of this error include mechanical assembly accuracy, component accuracy, and positioning accuracy of the linear drive shaft 20, and adjustment and measurement are difficult because multiple parameters are interrelated. Therefore, from here on, we will explain how to correct this error.

Here, in the 3D printer 1, the position (XY coordinates) and orientation of the head 40 and nozzle 41 in the horizontal plane are determined by the relative difference in the positional relationships of the six first ball joints 30. In contrast, the vertical position (Z coordinate) is determined by the absolute average height of the six first ball joints 30. Therefore, the position and orientation in the horizontal plane do not change with the above-mentioned probe operation.

Therefore, by mapping the correspondence between position and orientation on a single specific plane (e.g., the surface of the touch panel 91), it is possible to accommodate vertical changes that fall within the mapped range. In this embodiment, the calculation unit 83 makes corrections by utilizing this property.

Note that we have given an example of error in the horizontal plane (XY coordinates), but in reality there are also errors in the vertical height (Z coordinate) and attitude (tilt angle φ, rotation angle θ). These will also be corrected together.

(Correction by Calculation Unit 83)
10 is a flowchart showing a correction method by the calculation unit 83. A first list including a desired tilt angle φ is obtained from the calibration data (S21). Since the tilt angle φ is not necessarily measured data, the calculation unit 83 may generate the first list by the following method.

First, consider the case where the tilt angle φ satisfies φ1≦φ<φ2. Here, φ1 and φ2 are both the tilt angles of the posture in which the measurement was performed. In this case, the value of the tilt angle φ may be derived by linearly interpolating the values of the tilt angles φ1 and φ2 at the same horizontal plane position and the same rotation angle in the calibration data, and this value may be used as the first list.

A second list including the desired rotation angle θ is obtained from the first list (S22). Because the rotation angle θ is not necessarily measured data, the calculation unit 83 may generate the second list in the following manner.

First, consider the case where the rotation angle θ satisfies θ1≦φ<θ2. Here, θ1 and θ2 are both rotation angles of the attitude at which the measurement was performed. In this case, the value of the rotation angle θ may be derived by linearly interpolating the values of the rotation angle θ1 and the rotation angle θ2 in the first list, and used as the second list.

A third list including the desired horizontal position (X, Y) is obtained from the second list (S23). The third list may be used to derive each value at the desired horizontal position (X, Y). For example, as the third list, a first triangle α in FIG. 9 that includes the desired horizontal position (X, Y) is identified. A second triangle β in FIG. 8 that corresponds to the first triangle α is identified. The values of each point in the first triangle α and the second triangle β are the third list.

In the third list, a control command position at the desired tilt angle, rotation angle, and position in the horizontal plane is calculated (S24). Furthermore, in the third list, a control command attitude at the desired tilt angle, rotation angle, and position in the horizontal plane is calculated (S25). The method for calculating the control command position and control command attitude may use any projection relationship.

Figure 11 shows an example of a projection relationship for calculating a control command position and a control command attitude. In Figure 11, points ABC in the first triangle α correspond to points DEF in the second triangle β.

Point P in the first triangle α is the desired position in the horizontal plane. Here, vector AP can be decomposed into a resultant vector obtained by multiplying vectors AB and AC by a coefficient. The coefficients of the components of the decomposed vectors at this time are coefficients s and t.

Next, the horizontal position Q of the control command position is calculated by applying coefficients s and t to vectors DE and DF of the corresponding second triangle β. Vector DQ is the resultant vector of vector DE multiplied by coefficient s and vector DF multiplied by coefficient t.

Using these coefficients s and t, other values at point Q are calculated. The values to be calculated are the position in the horizontal plane (X, Y), the vertical height Z, the tilt angle φ, and the rotation angle θ at point Q. In this way, the control command position (X, Y, Z) and the control command attitude (φ, θ) are determined. As for the calculation method, when the value of point D is d, the value of point E is e, and the value of point F is f, the value q of point Q is determined by the following formula.
q=s(ed)+t(f-d)+d

(summary)
By controlling the 3D printer 1 using the control command position (X, Y, Z) and the control command attitude (φ, θ), it is possible to correct errors that occur due to the mechanism of the 3D printer 1. For the correction, various values can be measured by the measuring device 90.

(Modification)
The nozzle 41 is adjusted to a height that matches the focal length of the scanner 92 using the touch panel 91, but this is not limiting. For example, the vertical height of the position where the nozzle 41 should be located may be measured with a laser displacement meter, and then the position in the horizontal plane may be measured with a camera that is autofocused to match that height.

Furthermore, there is no particular limitation on the order of calculations performed by the calculation unit 83. For example, the rotation angle may be calculated first, then the tilt angle may be calculated, and finally the position within the horizontal plane may be calculated.
Furthermore, the measuring device 90 is not limited to a measuring device of a three-dimensional modeling device, but may be a measuring device for a parallel link mechanism having a mechanism similar to that of the 3D printer 1. Also, it may be a measuring device for a mechanism in which the nozzle 41 tilts and rotates, similar to that of the 3D printer 1. Furthermore, it is not limited to the nozzle 41, but may be an end effector.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Forms obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

1. 3D printer (3D modeling device)
LIST OF SYMBOLS 10 Frame 11 Upper frame 12 Lower frame 20, 20a to 20f Linear drive shaft 30, 30a to 30f First ball joint 40 Head 41 Nozzle 41a Tip 42 Load cell 50, 50a to 50f, 51 Second ball joint 52 Socket 53 Ball 54 Shaft 55 First rotating part 56 Arm 57 Second rotating part 60, 60a to 60f Link 70 Modeling stage 80 Control unit 81 Acquisition unit 82 Memory unit 83 Calculation unit 84 Command unit 90 Measuring device 91 Touch panel (tip height detection unit)
92 Scanner (horizontal position measurement unit)
93 Acceleration sensor (attitude detection unit)
100 3D modeling system

Claims (8)

A measurement device for a three-dimensional modeling device equipped with a nozzle for discharging a material,
a tip height detection unit that detects a vertical height of a tip of the nozzle;
and a horizontal position measuring unit that detects the position of the tip portion in a horizontal plane. The measurement device according to claim 1, wherein the horizontal position measurement unit measures the position optically. The measurement device according to claim 1, wherein the tip height detector detects contact of the tip with a specific plane. the tip height detection unit is a touch panel or a touch switch,
The measurement device according to claim 1 , wherein the horizontal position measurement unit is a scanner or a camera. The measurement device according to claim 1, further comprising a posture detection unit that measures the posture of the nozzle. A measurement method for a three-dimensional printing apparatus equipped with a nozzle that ejects a material, comprising the steps of:
a tip height detection step of detecting a vertical height of the tip of the nozzle;
and a horizontal position measuring step of measuring a position of the tip portion in a horizontal plane. A three-dimensional printing system including the three-dimensional printing device and the measurement device according to claim 1 ,
a storage unit that stores the vertical height and the position in the horizontal plane of the nozzle at a plurality of command positions and command attitudes;
a calculation unit that calculates a control command position and a control command attitude from the desired vertical height and the desired position in the horizontal plane based on the storage unit;
a control unit that controls the 3D printing device to the control command position and the control command attitude. A control method for a three-dimensional printing system including the three-dimensional printing apparatus and the measurement apparatus according to claim 1 , comprising:
a storing step of storing the vertical height and the horizontal position of the nozzle at a plurality of command positions and command attitudes;
a calculation step of calculating a desired command position and a command attitude from the desired vertical height and the desired position in the horizontal plane based on the storage unit;
and controlling the three-dimensional printing apparatus to the desired command position and command attitude.

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