JP7800928B2 - machine tool equipment - Google Patents

Description

The present invention relates to a machine tool device.

Conventionally, 3D printers are known that build up layers of material to create a workpiece based on 3D data created using 3D (Three-Dimensional)-CAD (Computer-Aided Design) or 3DCG (Computer Graphics). 3D printers use a variety of modeling methods. For example, there are fused deposition modeling (FDM) 3D printers that build up workpieces by layering thermally fused material. FDM 3D printers have a spindle that moves a discharge part that discharges molten resin or other material in three dimensions (or two dimensions), and a control unit that controls the spindle moves the spindle in three dimensions to create the workpiece.

There is also known a 3D printer in which a modeling device that dispenses material is moved in three dimensions by a robot arm. Patent Document 1 discloses a robot arm that changes at least one of the position, posture, and orientation of the modeling device, and a robot arm that changes at least one of the position, posture, and orientation of the workpiece holder.

Japanese Patent Application Laid-Open No. 2021-187076

However, in 3D printers that move a modeling device in three dimensions to create a model, if the weight of the modeling device increases in inertia, the modeling device may vibrate as it moves, reducing the positioning accuracy of the modeling device and potentially reducing the modeling accuracy of the created object.

Furthermore, in order to increase the rigidity of the robot arm that moves the modeling device, it is necessary to increase the rigidity of the parts that make up the robot arm, which requires the robot arm to be made larger or heavier, which can result in an increase in the size of the 3D printer and an increase in device costs.

The present invention was made in consideration of the above circumstances, and one of its objectives is to provide a machine tool device that can improve the molding accuracy of objects while reducing equipment costs.

To solve the above problems, the machine tool device of the embodiment includes a modeling device that discharges material from a discharge nozzle to form a model, a mounting unit that mounts the modeling device and whose position is fixed in three-dimensional space, a mounting table that places an object to be formed by receiving the material discharged from the modeling device, a moving device that moves the mounting table in the space in accordance with a modeling program for forming the object, and a control unit that executes the modeling program.

According to one embodiment of the present invention, a machine tool device includes a modeling device that discharges material from a discharge nozzle to form a shape; a mounting unit that mounts the modeling device and whose position is fixed in three-dimensional space; a mounting table that places an object to be formed by receiving the material discharged from the modeling device; a moving device that moves the mounting table in space in accordance with a modeling program for forming the object; and a control unit that executes the modeling program. By doing so, it is possible to improve the modeling accuracy of the object and reduce the cost of the device.

1 is a diagram illustrating an example of an external appearance of a machine tool device according to an embodiment. 1A is a diagram illustrating an example of a state where a tool is attached to a spindle, and FIG. 1B is a diagram illustrating an example of a state where a molding device is attached to a spindle in an embodiment. FIG. 2 is a diagram illustrating an example of a gripping device that grips the molding device in the embodiment. FIG. 2 is a diagram illustrating an example of a production area according to an embodiment. 10A and 10B are diagrams illustrating an example of a method for calculating a weight change and a center of gravity change in an embodiment. FIG. 10 is a diagram illustrating an example of a method for purging a material according to an embodiment. FIG. 10 is a diagram illustrating an example of a method for disposing of a purge material in an embodiment. 5A to 5C are diagrams illustrating an example of a method for cleaning a discharge nozzle in an embodiment. 10 is a flowchart illustrating an example of a replacement operation of the molding apparatus according to the embodiment. 10 is a flowchart illustrating an example of a material purging operation according to an embodiment. 10 is a flowchart illustrating an example of a cleaning operation of a discharge nozzle in the embodiment. 10 is a flowchart illustrating an example of a modeling operation in the embodiment. 10 is a flowchart illustrating an example of a forming control process according to an embodiment. 10 is a flowchart illustrating an example of a horizontal correction operation of the mounting table in the embodiment.

The machine tool device according to one embodiment of the present invention will be described in detail below with reference to the drawings. Note that identical components in each drawing will be assigned the same reference numerals, and their description may be omitted.

Figure 1 is a diagram showing an example of the external appearance of a machine tool device in an embodiment. In Figure 1, the machine tool device 1 has a spindle 11, a clamping mechanism 111, a material supply unit 112, a tool storage area 12, a modeling device storage area 13, a production area 14, a tool shutter 15, a modeling device shutter 16, and a butler device 7.

In this embodiment, the machine tool device 1 is a device that ejects material into a three-dimensional space defined by mutually perpendicular x-, y-, and z-axes to form a shape, such as a 3D printer. In Figure 1, the x-axis is the left-right direction on the drawing, the y-axis is a direction perpendicular to the plane of the drawing (not shown), and the z-axis is the up-down direction on the drawing. In other words, Figure 1 is a plan view on the x-z plane. Details of the forming method using the Butler device 7 will be described later.

The machine tool device 1 has a spindle 11. The spindle 11 has a clamping mechanism 111 and a material supply unit 112.

The clamping mechanism 111 has a clamping function for automatically changing tools. "Clamping" refers to grasping or clamping. The clamping function is a function (device structure) used, for example, in automatic tool changers (ATCs) used in machine tools such as machining centers. The clamping mechanism 111 automatically changes (attaches) (detaches) tools from the spindle 11 by clamping or unclamping a tool to be used for machining from among multiple tools. The shape of the clamping mechanism 111 is determined, for example, by industrial standards for ATC tapered shanks, such as the MAS standard (Japan Machine Tool Builders' Association standard), the DIN standard (Deutsche Industrie Norm), or the ANS standard (American National Standards Institute standard). The clamping mechanism 111 can clamp, for example, using an HSK type (ISO 12164-1:2001 or ISO 12164-3:2008, ISO: International Organization for Standardization) that restrains two surfaces of the tool 2.

Note that while Figure 1 shows tool 2 clamped to clamping mechanism 111, it is possible to clamp a modeling device instead of tool 2 to clamp mechanism 111. Clamping mechanism 111 can fix the position of the modeling device in a three-dimensional space made up of mutually orthogonal x-, y-, and z-axes (hereinafter sometimes referred to as the x-axis, etc.). In other words, while the modeling device is modeling, the modeling device is fixed in 3D space.

The material supply unit 112 supplies the modeling material used by the modeling device when the modeling device is clamped by the clamping mechanism 111. Details of the modeling device and the material supply unit 112 will be described later.

The tool storage area 12 is an area for storing tools 2 clamped by the clamping mechanism 111. The tool storage area 12 includes an automatic tool change (ATC) mechanism (not shown) for tool automatic change. The tools 2 stored in the tool storage area 12 are attached to the spindle 11 by, for example, the ATC mechanism.

The modeling device storage area 13 is an area for storing modeling devices (described below) that are clamped by the clamping mechanism 111. The modeling devices are placed at predetermined positions in the modeling device storage area 13. The clamping mechanism 111 is attached via the spindle 11 of the machine tool device 1. The modeling device storage area 13 includes a holding mechanism (not shown) for holding the modeling devices. The modeling devices stored in the modeling device storage area 13 are moved and attached to the spindle 11 by the butler device 7 (described below).

The production area 14 is a space for producing workpieces by machining using tools or by molding using a molding device. The spindle 11 has an internal rotation mechanism (not shown) for rotating tools in the production area 14 or for discharging material from the molding device. The start and stop of the rotation mechanism, as well as the rotation speed of the rotation mechanism, are controlled by a control unit described below. In this embodiment, the spindle 11 includes a casing with an internal rotation mechanism. Note that the rotation of the rotation mechanism inside the spindle 11 may sometimes be referred to simply as the rotation of the spindle 11.

The tool shutter 15 is a shutter that separates the tool storage area 12 from the production area 14. The modeling device shutter 16 is a shutter that separates the modeling device storage area 13 from the production area 14. The tool shutter 15 and modeling device shutter 16 have opening and closing mechanisms that are controlled to open and close in response to the attachment and detachment of the tool 2 and the attachment and detachment of the modeling device.

Note that if the modeling device described below is a printer head that performs FDM modeling, the modeling device can become a heat source because the material is melted by applying heat or pressure to the solid material. Meanwhile, the machining accuracy of mechanical parts such as the spindle 11 of the machine tool device 1, or the workpiece, may decrease due to thermal expansion caused by temperature changes. The modeling device shutter 16 thermally isolates the modeling device, which is a heat source, from the production area 14, thereby preventing heat transfer to the production area 14. Furthermore, the tool shutter 15 and modeling device shutter 16 prevent contamination of the tool storage area 12 and modeling device storage area 13, respectively, due to cutting dust and other particles generated in the production area 14.

Next, the attachment of a tool or a modeling device to the spindle will be described using Figure 2. Figure 2 shows an example of (A) attaching a tool to the spindle 11, and (B) attaching a modeling device to the spindle 11 in an embodiment. Figures 2(A) and 2(B) show details of the machine tool 1 in Figure 1, mainly the spindle 11. Here, Figure 2(A) shows the tool 2 clamped to the clamping mechanism 111. Also, Figure 2(B) shows the modeling device 3 clamped to the clamping mechanism 111.

In Figure 2(A), the spindle 11 has a clamping mechanism 111, a material supply unit 112, and a power supply unit 113A.

The clamping mechanism 111 is attached to the lower end of the spindle 11. Therefore, by fixing the position of the spindle 11 in three-dimensional space, the position of the clamping mechanism 111 is also fixed. The spindle 11 rotates the tool 2 clamped by the clamping mechanism 111 using a rotation mechanism (not shown) provided on the spindle 11. The rotation of the spindle 11 (the rotation of the clamped tool 2) is controlled by a control program executed by the control unit, which will be described later. The control program includes, for example, control commands for instructing the start or stop of rotation of the spindle 11, or control commands for specifying the rotation speed of the spindle 11. The control program can be, for example, an NC (numerical control) program.

The material supply unit 112 and the power supply unit 113A are attached to the spindle 11. The material supply unit 112 is a supply mechanism for supplying material for modeling when the modeling device 3 is clamped by the clamping mechanism 111. Therefore, when the modeling device 3 is not clamped, no material is supplied from the material supply unit 112. The power supply unit 113A supplies power to the modeling device 3 when the modeling device 3 is clamped by the clamping mechanism 111. Details of the material supply unit 112 and the power supply unit 113A will be explained in Figure 2 (B).

The butler device 7 has an XY movement device 71, a robot arm 72, and a mounting table 73. The butler device 7 mounts and moves in three dimensions the workpiece to be machined by the tool 2 or the object to be molded by the molding device 3.

In Figure 2 (B), a clamping mechanism 111 attached to the lower end of the spindle 11 clamps the molding device 3. The tool 2 and molding device 3 can be automatically exchanged by the clamping mechanism 111. By automatically exchanging the tool 2 and molding device 3, it becomes possible to continuously process materials and mold them in the same production area 14. Therefore, compared to performing processing and molding using separate devices, it is possible to reduce equipment costs, reduce the number of steps required for setting up the workpiece, improve equipment availability, and reduce costs by sharing the programs used for machining.

The molding device 3 has a power receiving unit 113B, a discharge nozzle 31, a storage unit 32, a tilting unit 321, a heating unit 322, a heat retention unit 33, a melting unit 34, and a transfer unit 35.

The modeling device 3 is, for example, the head portion of an FDM printer, which melts the supplied material and ejects the molten material from the ejection nozzle 31. In the following example, the material modeling method will be described as an FDM modeling method, but the modeling device 3 may also use other methods used in 3D printers, such as a photolithography method in which ejected liquid material is hardened with ultraviolet light or the like, or a powder fixing method in which powder and binder are ejected and solidified.

The discharge nozzle 31 discharges molten material for forming the workpiece. The storage unit 32 stores the material supplied from the material supply unit 112. The heating unit 322 heats and melts the material stored in the storage unit 32. The inclined unit 321 collects the material melted by the heating unit 322 by gravity and supplies it inside the heat retention unit 33. The heat retention unit 33 keeps the molten material warm. The melting unit 34 reheats or adjusts the temperature of the molten material. The transfer unit 35 transfers the molten material stored in the heat retention unit 33 and discharges it from the discharge nozzle 31.

When the modeling device 3 is clamped by the clamping mechanism 111, the material supply unit 112 faces the storage unit 32 and supplies material to the storage unit 32. By facing the material supply unit 112 and the storage unit 32 when the modeling device 3 is clamped, it becomes possible to automatically supply material continuously to the modeling device 3. This makes it possible to improve the operating rate of the machine tool 1 compared to, for example, manually supplying material each time material runs out.

The material supply unit 112 has a hollow structure and supplies material to the storage unit 32 by moving the material through the hollow structure (e.g., a flexible hose, etc.). When supplying material to the storage unit 32, the material supply unit 112 may use, for example, compressed air or a transfer pump. To supply material using compressed air, for example, the material can be moved inside the material supply unit 112 using the pressure of the compressed air. To supply material using a transfer pump, for example, the material can be moved inside the material supply unit 112 using a rotary positive displacement uniaxial eccentric screw pump.

The supply of material may be controlled, for example, to maintain a constant amount of material stored in the storage unit 32. For example, a sensor (not shown) attached to the storage unit 32 may detect when the amount of material stored is low, and the material may be automatically supplied. By automatically maintaining a constant amount of stored material, the supply of material can be automated.

A heating unit 322 is attached to the inclined portion 321 and heats the material stored in the storage unit 32. The heating unit 322 has a heater (shown by the dashed line) positioned diagonally upward inside the storage unit 32. This increases the area of contact between the heater and the material, making it easier to melt the material. The heating unit 322 may be configured to heat (preheat) the material to approximately the melting temperature at which it melts. Materials with high heat capacity are difficult to cool once their temperature rises, making temperature control by cooling difficult. Preheating the material in the heating unit 322 facilitates temperature control in the melting unit 34 and reduces the heating load in the melting unit 34, making it possible to miniaturize the melting unit 34. Alternatively, the heating unit 322 may heat the material to the temperature required for discharge, thereby eliminating the need to heat the material in the melting unit 34.

When the modeling device 3 is clamped by the clamping mechanism 111, the power receiving unit 113B faces the power supply unit 113A and receives the power supplied from the power supply unit 113A. The combination of the power supply unit 113A and the power receiving unit 113B forms the power supply mechanism 113. The power supplied by the power supply mechanism 113 is used by the heating unit 322 or the melting unit 34. Note that the power supply unit 113A that faces the power receiving unit 113B and supplies power is sometimes referred to as the power supply mechanism. For example, even when the modeling device 3 is not clamped by the clamping mechanism 111, the machine tool device 1 is considered to have a power supply mechanism (power supply unit 113A).

The power supply mechanism 113 supplies power by contacting the contacts of the power supply unit 113A and the contacts of the power receiving unit 113B when the modeling device 3 is clamped by the clamping mechanism 111. This makes it possible to supply power to the modeling device 3 clamped by the clamping mechanism 111. A contact connector mechanism can be used for the power supply mechanism 113. Using a contact connector mechanism simplifies the structure and makes it possible to supply power at low cost. Furthermore, by gold-plating the contacts, for example, it is possible to stabilize the electrical resistance caused by the contacts.

The power supply mechanism 113 may also use a non-contact (wireless) power supply system in which the power supply unit of the power supply unit 113A and the power receiving unit of the power receiving unit 113B come into close proximity when the modeling device 3 is clamped by the clamping mechanism 111 to supply power. For example, the power supply unit of the power supply unit 113A may be provided with a power supply coil, and the power receiving unit of the power receiving unit 113B may be provided with a power receiving coil, and power may be supplied by receiving electromagnetic waves generated from the power supply coil with the power receiving coil. By using a non-contact power supply system in the power supply mechanism 113, it is possible to prevent power supply problems caused by poor contact at the contact points.

Power may also be supplied to the modeling apparatus 3 using a power generating device (not shown) provided in the modeling apparatus 3. The power generating device may be, for example, a generator whose rotor rotates when the main shaft 11 is rotated. For example, the generator may be one whose rotor rotates in conjunction with the rotation of the conveying mechanism that discharges the material. The generator may also be one whose rotor rotates by switching between the rotation of the conveying mechanism that discharges the material and the transmission of rotational force. By using a power generating device provided in the modeling apparatus 3 to supply power to the modeling apparatus 3, it is possible to omit the power supply mechanism in the main shaft 11. The power supply mechanism 113 may generate power by rotating the rotor of the generator provided inside the power receiving unit 113B by joining the rotation mechanism of the power supply unit 113A and the rotation mechanism of the power receiving unit 113B so that rotational force can be transmitted when the modeling apparatus 3 is clamped by the clamping mechanism 111. For example, the rotation mechanism of power supply unit 113A may be rotated by a control command, which in turn rotates the rotation mechanism of power receiving unit 113B, thereby rotating the rotor of the generator. By generating electricity using a generator built into power receiving unit 113B, it is possible to omit the electrical connection between power supply unit 113A and power receiving unit 113B.

The heat retention unit 33 keeps the material supplied from the inclined unit 321 warm. The heat retention unit 33 has an insulating layer, like a thermos, to prevent the temperature of the material from being transferred outside the modeling device 3. By keeping the material warm, for example, when the material is melted in the heating unit 322, the temperature of the material can be maintained, and viscosity changes due to temperature changes in the material can be reduced.

The transfer unit 35 transfers and pressurizes the molten material stored in the heat retention unit 33 and discharges it from the discharge nozzle 31. The transfer unit 35, for example, has an internal screw and can transfer the material by rotating the screw. The rotation of the screw can be controlled by the rotation of the spindle 11. In other words, when the molding device 3 is clamped by the clamping mechanism 111, the screw of the transfer unit 35 rotates instead of the tool 2, making it possible to control the rotation of the screw by controlling the rotation of the spindle 11. For example, the machine tool device 1 can control the rotation of the screw based on a control command to start or stop the rotation of the tool 2. This allows the start or stop of material discharge to be controlled by the same control command as the rotation of the tool. The control command can be, for example, an M-code of an NC program. An M-code is a control command that defines auxiliary functions for machining in an NC program. M-codes are specified, for example, in the JIS (Japanese Industrial Standards) standard. For example, "M03" is a command to rotate the tool (spindle) forward, and "M05" is a command to stop the rotation of the tool. The "M03" command starts the discharge of material, and the "M05" command stops the discharge of material. By rotating the screw of the transfer unit 35 with the rotation of the spindle 11, it is possible to control the start or stop of material discharge without adding a new command to control the modeling device 3, making it possible to reduce the number of manufacturing steps.

The machine tool device 1 also controls the amount of material discharged by controlling the rotational speed of the transfer mechanism of the molding device 3 based on a control command for specifying the rotational speed of the tool. The control command for specifying the rotational speed of the tool can be implemented, for example, in the S code of an NC program. The S code is a control command for setting the rotational speed of the tool. For example, "S2000" is a command for rotating the tool at 2,000 rpm. The S code is used together with the M code described above. By controlling the rotational speed of the transfer mechanism in the S code, it is possible to control the amount of material discharged without adding a new command for controlling the molding device 3, making it possible to reduce production man-hours.

In the butler device 7, the XY moving device 71 is a movement mechanism that moves the robot arm 72 and mounting table 73 on the XY plane. For example, by combining slide guides or ball splines on the x and y axes and driving them with a motor, positioning on the XY plane is possible. Note that either the XY moving device 71 or the robot arm 72, or both the XY moving device 71 and the robot arm 72, may be referred to as the "moving device" in this embodiment, as they move the mounting table 73.

The robot arm 72 can move on the XY plane using the XY movement device 71, and can grasp the mounting table 73 and move it three-dimensionally along the x-, y-, and z-axes. The robot arm 72 can also change the inclination of the mounting table 73 it grasps. The inclination of the mounting table 73 refers to the inclination of the mounting surface of the mounting table 73 on which the object to be molded is placed. For example, the robot arm 72 can keep the inclination of the mounting surface at 0, i.e., horizontal, while molding the object. The robot arm 72 can also make the mounting surface vertical during the material purging operation or the discharge nozzle 31 cleaning operation, which will be described later. The robot arm 72 is, for example, a multi-axis (multi-joint) robot.

The robot arm 72 requires a certain output (output torque for each axis) to move or hold the mounting platform 73 it holds at a fixed position in three-dimensional space. When controlling the position of the robot arm 72, feedback control is performed to correct any discrepancies between the target position and the current position. Feedback control repeats the following steps: 1: A position discrepancy (error) occurs with respect to the target position → 2: The error is detected → 3: The position is corrected. This results in minute vibrations during feedback control. Adjusting the time constant in the control system is effective in reducing vibrations during feedback control. For example, a load torque corresponding to the weight of the mounting platform 73 is applied to each axis of the robot arm 72. If the weight of the mounting platform 73 (load torque for each axis) is known in advance, gain adjustment can be performed by applying a bias torque corresponding to the weight of the mounting platform 73 to each axis of the robot arm 72 in advance, thereby reducing vibrations of the mounting platform 73 during feedback control.

The mounting table 73 mounts the workpiece to be machined by the tool 2 or the object to be molded by the molding device 3. In this embodiment, the mounting table 73 is moved to mount (receive) the material dispensed from the molding device 3, which is fixed in position. Therefore, the molding method using the Butler device 7 is referred to as the Butler method, and the molding system using the Butler device 7 is referred to as the Butler system. In the Butler system, the molding device 3 is fixed, so even if the molding device 3 becomes heavy, vibrations of the molding device 3 caused by movement of the molding device 3 do not occur, thereby improving the molding accuracy of the object and reducing the cost of the device.

Next, we will explain how to replace the modeling device 3 in the Butler system using Figure 3. Figure 3 is a diagram showing an example of a gripping device that grips the modeling device in this embodiment.

In FIG. 3, the butler device 7 has a gripping device 74. The gripping device 74 is moved by the moving device to a gripping position where it grips the modeling device 3, and can grip the modeling device 3. The gripping device 74 grips the modeling device 3 and unclamps the clamping mechanism 111, allowing the modeling device 3 to be removed from the clamping mechanism 111. The removed modeling device 3 is moved by the moving device to the above-mentioned modeling device storage area 13 and stored therein. Note that the modeling device storage area 13 can store multiple modeling devices 3. The butler device 7 can replace the modeling device 3 by gripping a unique modeling device 3 stored in the modeling device storage area 13.

In addition, the gripping device 74 can exchange the tool 2 with the molding device 3 by gripping the tool 2 in the tool storage area 12.

Next, we will explain the production area using Figure 4. Figure 4 is a diagram showing an example of a production area in an embodiment.

In Figure 4, the machine tool device 1 has a control unit 10, a spindle 11, a clamping mechanism 111, a tool storage area 12, a modeling device storage area 13, a production area 14, a tool shutter 15, a modeling device shutter 16, and a discharge area 17.

The control unit 10 has a modeling control unit 101 and a modeling device exchange control unit 102. The control unit 10 is, for example, a computer that controls the machine tool device 1, and controls, for example, the NC program described above. The modeling control unit 101 and the modeling device exchange control unit 102 can be implemented in a program that runs on the control unit 10. In other words, the modeling control unit 101 and the modeling device exchange control unit 102 can be implemented as functional units that function using software. However, at least one of the modeling control unit 101 and the modeling device exchange control unit 102 may be implemented on a computer independent of the control unit 10, or may be implemented using hardware.

The modeling control unit 101 controls modeling using the modeling device 3 by controlling the clamping operation of the clamping mechanism 111, controlling the rotation of the spindle 11 (rotation/stop and rotation speed control), controlling the supply of material by the material supply unit 112, controlling the opening and closing of the tool shutter 15 and modeling device shutter 16, controlling the heating of the heating unit 322 and melting unit 34, controlling the movement of the XY moving device 71, controlling the movement of the robot arm 72, and controlling the gripping of the gripping device 74.

The modeling control unit 101 also calculates the amount of change in the weight of the model, as described below, calculates the amount of change in the center of gravity of the model, controls the purging operation of the material, or controls the cleaning operation of the discharge nozzle 31.

The discharge area 17 is an area for discharging the formed object. The mounting table 73 on which the formed object is placed is moved to the discharge area 17 by a moving device. In the discharge area 17, an operator can remove the formed object from the mounting table 73. In the Butler system, the mounting table 73 can be moved to the discharge area 17, making it easier for an operator to remove the formed object. Furthermore, by installing a device such as a conveyor for discharging the formed object in the discharge area 17, the Butler system enables automatic discharge of the formed object. Note that the discharge area 17 may also be provided with a shutter, similar to the modeling device storage area 13, etc.

Next, a method for calculating weight changes and center of gravity changes during the modeling process will be described using Figure 5. Figure 5 is a diagram showing an example of a method for calculating weight changes and center of gravity changes in an embodiment.

In Figure 5, the mounting table 73 has a mounting surface 730. Material mt ejected from an ejection nozzle 31 (not shown) is placed on the mounting surface 730. Figure 5 shows a case where the mounting surface 730 is horizontal to the xy plane. In this embodiment, the mounting table 73 has a constant thickness, and the mounting surface 730 is square. Before modeling, the center of gravity of the mounting table 73 is the center of the mounting surface 730, which is the center of gravity point C00.

As described above, a load torque corresponding to the weight of the mounting table 73 is applied to each axis of the robot arm 72 (not shown). Before modeling, the weight of the mounting table 73 is constant, so the bias output can be kept constant. On the other hand, after modeling begins, a load corresponding to the dispensed material is added to the mounting table 73. Here, the load torque applied to each axis of the robot arm 72 can be calculated from the weight of the material dispensed onto the mounting surface 730 and the dispensed position of the material on the mounting surface 730.

Here, after the start of modeling, the material mt is discharged onto the mounting surface 730 over a length L1. If the material discharged from the discharge nozzle 31 (not shown) has a diameter D1 and a specific gravity (specific weight) of the material is γ, the control unit 10 (not shown) can calculate the weight G1 of the material mt as G1 = γ * (D1/2) ² * L1. The control unit 10 can use the discharge amount calculated from the rotation amount of the main shaft 11 of the modeling device 3 as the volume of the material (D1/2) ² * L1. The control unit 10 may also calculate the volume D1 * L1 by regarding the gap between the discharge nozzle 31 and the mounting surface 730 as the diameter D1. If the weight of the mounting table is G0, the load weight on the robot arm 72 is G0 + G1. Note that the length L1 is a value based on the center of the material mt set in the modeling program, and therefore may have some discrepancy with the actual weight.

The center of gravity of the material mt over length L1 is center of gravity C1, which is the midpoint of length L1. The control unit 10 can calculate the center of gravity on the mounting surface 730 after the material mt has been dispensed over length L1 to be center of gravity C01, which is the combination of center of gravity C0 and center of gravity C1. When the robot arm 72 grasps the mounting table 73 at center of gravity C00, no load torque is required to keep the mounting surface 730 horizontal to the xy plane before modeling. On the other hand, after the material mt has been dispensed over length L1, a load torque is generated depending on the distance between center of gravity C00 and center of gravity C01. The control unit 10 can prevent vibration of the mounting table 73 by applying a bias torque depending on the load torque generated as the center of gravity moves.

Next, the material mt is discharged onto the placement surface 730 over a length L2 perpendicular to L1. The control unit 10 can calculate the weight G2 of the material mt over the length L2 as G2 = γ * D1 * L2. The cumulative load weight on the robot arm 72 is G0 + G1 + G2.

The center of gravity of the material mt over length L2 is center of gravity C2, which is the midpoint of length L2. The control unit 10 can calculate the center of gravity on the placement surface 730 after the material mt has been dispensed over length L2 as center of gravity C02, which is the combination of center of gravity C01 and center of gravity C2. After the material mt has been dispensed over length L2, a load torque is generated according to the distance between center of gravity C00 and center of gravity C02. The control unit 10 can prevent vibration of the placement table 73 by applying a bias torque according to the load torque generated as the center of gravity moves.

Next, a method for purging material before modeling will be described using Figure 6. Figure 6 shows an example of a method for purging material in an embodiment.

In Figure 6, a tray 731 is attached to the side of the mounting table 73. The tray 731 receives the material purged from the discharge nozzle 31. Purging material is the operation of discharging material that has accumulated inside the molding device 3, and is sometimes referred to as the purging operation. The component of the machine tool device 1 that performs the purging operation is sometimes referred to as the purging means.

For example, the temperature of the material melted by the heating unit 322 of the above-mentioned modeling device 3 decreases over time, and it may change (solidify, oxidize, etc.) inside the discharge nozzle 31. Since the changed material cannot be used for modeling, it must be purged before modeling. The control unit 10 can purge the material by, for example, rotating the main shaft 11.

The control unit 10 causes the robot arm 72 to raise the mounting table 73 upright and move the tray 731 to the vicinity (below) of the discharge nozzle 31. The tray 731 can be moved, for example, by setting a new TCP (Tool Center Point) for the robot arm 72. The TCP is a coordinate system set according to the tool held by the robot arm 72. In this embodiment, by setting the destination of the tray 731 to the TCP, the purging operation can be performed in a coordinate system separate from the coordinate system related to the modeling, making it easier to program the operation of the robot arm 72. The control unit 10 then discharges (purges) a predetermined amount of material from the discharge nozzle 31. The purged material is stored in the tray 731.

By attaching the tray 731 to the mounting table 73, the robot arm 72 can perform the purging operation while holding the mounting table 73, thereby reducing the amount of work required to change the tool being held.

Figure 7 illustrates a method for disposing of purged material. Figure 7 shows an example of a method for disposing of purged material in an embodiment.

In Figure 7, the mounting table 73 is inverted from the state shown in Figure 6 so that the receiving tray 731 faces downward. The mounting table 73 is inverted by a robot arm 72 (not shown). The material purged into the receiving tray 731 falls downward and is collected in the waste tray 75. If the material collected in the receiving tray 731 does not fall easily, for example, the receiving tray 731 and the waste tray 75 may be brought into contact with each other to shake out the material. By collecting the purged material in the waste tray 75, it is possible to prevent the weight of the mounting table 73 from increasing and the center of gravity from shifting due to the purged material.

Next, a method for cleaning the discharge nozzle 31 will be described using Figure 8. Figure 8 is a diagram showing an example of a method for cleaning the discharge nozzle in this embodiment.

In Figure 8, a wiping portion 732 is attached to the side of the mounting table 73. The wiping portion 732 is a member for wiping off material that has spilled over from the discharge nozzle 31 and adhered to the discharge nozzle 31. The wiping portion 732 can be made of a material that easily transfers material that has adhered to the discharge nozzle 31, such as felt, sponge, or cloth.

The modeling device 3 described in Figure 2 ejects material that has been heated and melted in the heating unit 322 (and melting unit 34) from the discharge nozzle 31 by rotating the main shaft 11. However, material that has melted and reduced in viscosity may drip from the discharge nozzle 31 even without rotating the main shaft 11. Dripping material before modeling begins may adhere to the discharge nozzle 31 and clog the discharge nozzle 31. Dripping material may also adhere to the modeled object and form burrs, which may adversely affect the shape of the modeled object. In this embodiment, before modeling is performed in the modeling device 3, the wiping unit 732 is brought into contact with the discharge nozzle 31 to clean the material adhering to the discharge nozzle 31.

The wiping unit 732 is attached to the mounting base 73, and moves in the v direction while remaining in contact with the discharge nozzle 31 as the robot arm 72 moves the mounting base 73. The wiping unit 732 comes into contact with the discharge nozzle 31 when the robot arm 72 is in force mode. Force mode is a mode in which the robot arm 72 can press with a predetermined force in a predetermined direction. In force mode, the wiping unit 732 can be pressed against the discharge nozzle 31 with a constant force F regardless of the gap (positional relationship) between the wiping unit 732 and the discharge nozzle 31. By moving the mounting base 73 in the v direction, which is perpendicular to the direction of force F, the robot arm 72 can clean the discharge nozzle 31 while pressing the wiping unit 732 against the discharge nozzle 31 with force F. This allows material adhering to the discharge nozzle 31 to be transferred to a wide area of the wiping unit 732.

Next, the replacement operation of the modeling device 3 will be described using Figure 9. Figure 9 is a flowchart showing an example of the modeling device replacement operation in this embodiment. Note that in the flowcharts from Figure 9 onwards, the operation is described as being performed by the control unit 10, but it may also be performed by a configuration other than the control unit 10 (e.g., another control unit), for example.

In FIG. 9, the control unit 10 determines whether or not to replace the modeling device 3 (step S11). Replacing the modeling device 3 includes replacing the modeling device 3 with the tool 2, and replacing the modeling device 3 with another modeling device 3. If it is determined that the modeling device 3 will not be replaced (step S11: NO), the control unit 10 ends the operations shown in the flowchart and waits for the modeling device 3 to be replaced.

On the other hand, if it is determined that the modeling device 3 should be replaced (step S11: YES), the control unit 10 replaces the modeling device 3 using the Butler system described above (step S12). By replacing the modeling device 3 using the Butler system, the modeling device 3, which is fixed in position, can be replaced automatically, reducing the man-hours required for replacing the modeling device 3.

Next, the material purging operation before the modeling operation will be described using Figure 10. Figure 10 is a flowchart showing an example of the material purging operation in this embodiment.

In FIG. 10, the control unit 10 determines whether or not to perform a purge operation (step S21). Whether or not to perform a purge operation may be determined based on, for example, the elapsed time since the end of the previous modeling operation, whether or not the material used for modeling has been changed, the temperature of the molten material, or the number or time of modeling. If it is determined not to perform a purge operation (step S21: NO), the control unit 10 terminates the operation shown in the flowchart.

On the other hand, if it is determined that a purge operation should be performed (step S21: YES), the control unit 10 moves the tray 731 to the vicinity of the discharge nozzle 31 (step S22). After performing the process of step S22, the control unit 10 purges the material remaining inside the modeling device 3 and stores it in the tray 731 (step S23). After performing the process of step S23, the control unit 10 stores the purged material stored in the tray 731 in the waste tray 75 (step S24). After performing the process of step S24, the control unit 10 returns the mounting table 73 to the origin (step S25). The origin of the mounting table 73 in this embodiment can be set, for example, by TCP.

Next, the cleaning operation of the discharge nozzle 31 before modeling will be described using Figure 11. Figure 11 is a flowchart showing an example of the cleaning operation of the discharge nozzle in this embodiment.

In FIG. 11, the control unit 10 determines whether or not to perform a cleaning operation (step S31). Whether or not to perform a cleaning operation may be determined based on, for example, the state of the discharge nozzle 31, the time elapsed since the previous modeling operation ended, whether or not a purging operation has been performed, etc. If it is determined that a cleaning operation will not be performed (step S31: NO), the control unit 10 ends the operation shown in the flowchart.

On the other hand, if it is determined that a cleaning operation should be performed (step S31: YES), the control unit 10 brings the wiping unit 732 into contact with the discharge nozzle 31 in force mode (step S32). After performing the process of step S32, the control unit 10 moves the wiping unit 732 in a direction perpendicular to the force mode (step S33). After performing the process of step S33, the control unit 10 returns the mounting table 73 to the origin (step S34). The origin of the mounting table 73 in this embodiment can be set, for example, by TCP.

Next, the modeling operation will be described using Figures 12 and 13. Figure 12 is a flowchart showing an example of the modeling operation in this embodiment. Figure 13 is a flowchart showing an example of modeling control in this embodiment.

In FIG. 12, the control unit 10 determines whether or not to start a workpiece molding operation using a material (step S41). The molding operation is the molding of a material using the molding device 3, and refers to operating the machine tool device 1 as a so-called 3D printer. If it is determined not to start the molding operation (step S41: NO), the control unit 10 ends the operation shown in the flowchart.

On the other hand, if it is determined that the modeling operation should be started (step S41: YES), the control unit 10 starts modeling control (step S42). In modeling control, the Butler system models the material, thereby improving the modeling accuracy of the modeled object. Details of the modeling control in step S42 will be explained using Figure 13.

In FIG. 13, the control unit 10 starts the modeling operation of discharging material from the discharge nozzle 31 (step S421). The control unit 10 calculates the node weight (step S422). A node refers to a portion of the discharged material. A node is expressed, for example, as the length of the discharged material on the placement surface 730. The nodes described in FIG. 5 were described as straight lines with lengths L1 and L2. Nodes may be set, for example, for each unit length (e.g., 1 cm). The node weight is the weight of each node and is calculated as the specific gravity γ of the material * the volume V of the node.

After executing the process of step S422, the control unit 10 calculates the node center of gravity (step S423). The node center of gravity is the center of gravity of each node and can be calculated based on the node shape. After executing the process of step S423, the control unit 10 calculates the cumulative value of the node weight and the cumulative value of the node center of gravity, and corrects the output of the robot arm 72 based on the calculated cumulative value of the node weight and the cumulative value of the node center of gravity (step S424). By correcting the output of the robot arm 72, the control system of the robot arm 72 can be stabilized and vibration of the mounting table 73 can be reduced, thereby improving the molding accuracy of the object.

After executing the processing of step S424, the control unit 10 determines whether the formation of all nodes has been completed (step S425). Whether the formation of all nodes has been completed can be determined, for example, by whether the formation of one formation device 3 has been completed. If it is determined that the formation of all nodes has not been completed (step S425: NO), the control unit 10 repeats the processing of steps S422 to S425. On the other hand, if it is determined that the formation of all nodes has been completed (step S425: YES), the control unit 10 ends the formation control operation.

Returning to FIG. 12, after executing the process of step S42, the control unit 10 determines whether or not to end the modeling (step S43). End of modeling refers to a state in which the modeled object can be discharged. For example, if additional modeling processing is to be performed, it can be determined not to end the modeling. If it is determined not to end the modeling (step S43: NO), the control unit 10 returns to step S42 and waits for the modeling to end.

On the other hand, if it is determined that the modeling should be completed (step S43: YES), the control unit 10 discharges the modeled object in the Butler system (step S44). After executing the process of step S44, the control unit 10 ends the operation shown in the flowchart.

Next, the horizontal correction operation of the mounting base 73 will be described using Figure 14. Figure 14 is a flowchart showing an example of the horizontal correction operation of the mounting base 73 in this embodiment.

In FIG. 14 , the control unit 10 determines whether to perform a horizontal correction operation for the mounting table 73 (step S51). The mounting table 73 is held by the robot arm 72 as described above. The position (rotation angle) of each axis of the robot arm 72 is feedback-controlled, making it less likely for errors to occur over time. However, the mounting table 73 is simply held by the robot arm, and no feedback control is performed to detect its horizontality (tilt of the mounting table 73). For this reason, the horizontality of the mounting table 73 may become misaligned due to a printing operation, etc. If the horizontality of the mounting table 73 becomes misaligned, the entire model may tilt, resulting in a decrease in the modeling accuracy of the model. Whether to perform a horizontal correction operation may be determined based on, for example, the past printing time, the number of times printing has been performed, or the weight of the model. If it is determined not to perform a horizontal correction operation (step S51: NO), the control unit 10 terminates the operation shown in the flowchart.

On the other hand, if it is determined that a horizontal correction operation should be performed (step S51: YES), the control unit 10 raises the mounting base 73 to bring it into contact with the discharge nozzle 31, measures the gap between the discharge nozzle 31 and the mounting base 73, and confirms the horizontality of the mounting base 73 from the measured gap. The control unit 10 confirms the horizontality of the mounting base 73 by bringing the discharge nozzle 31 into contact with the mounting base 73 at at least three points on the plane of the mounting base 73 (step S52). Note that when bringing the discharge nozzle 31 into contact with the mounting base 73, the control unit 10 can use the force mode of the robot arm 72. Using the force mode can prevent damage to the discharge nozzle 31, mounting base 73, etc. due to contact.

After executing the process of step S52, the control unit 10 corrects the horizontality of the mounting table 73 (step S53). The horizontality of the mounting table 73 is corrected by adjusting the posture of the robot arm 72 so that the multiple measured gaps between the discharge nozzle 31 and the mounting table 73 are consistent. Note that if there is a large difference in the multiple gaps, there may be a problem with the way the robot arm 72 is gripping the mounting table 73. In this case, instead of performing the correction operation of step S53, the operation may be stopped and an error notification or other operation may be performed. After executing the process of step S53, the control unit 10 returns the mounting table 73 to the origin (step S54). In this embodiment, the origin of the mounting table 73 can be set, for example, by TCP.

The above describes an embodiment of the present invention with reference to the drawings, but the specific configuration is not limited to this embodiment and various modifications are also possible within the scope of the present invention.

1 Machine tool device 10 Control unit 101 Forming control unit 102 Forming device exchange control unit 11 Spindle 111 Clamping mechanism 112 Material supply unit 113 Power supply mechanism 113A Power supply unit 113B Power receiving unit 12 Tool storage area 13 Forming device storage area 14 Production area 15 Tool shutter 16 Forming device shutter 17 Discharge area 2 Tool 3 Forming device 31 Discharge nozzle 32 Storage unit 321 Inclined unit 322 Heating unit 33 Heat retention unit 34 Melting unit 35 Transfer unit 36 Local cooling/heating unit 51 Valve array 52 Cooling pipe 7 Butler device 71 XY moving device 72 Robot arm 73 Placement table 730 Placement surface 731 Receptacle 732 Wiping unit 74 Grip device 75 Disposal tray

Claims (9)

a modeling device that discharges a material from a discharge nozzle to form a shape;
a mounting portion to which the modeling device is attached, the mounting portion being fixed in position in three-dimensional space;
a mounting table on which a model to be formed by receiving the material dispensed from the modeling device is placed;
a moving device that moves the mounting table in the space in accordance with a modeling program for forming the object;
a control unit that executes the modeling program,
The control unit
calculating a change in weight of the object during the modeling process based on the weight of the material discharged from the modeling device;
Sequentially correcting the load value of the stage in the moving device based on the calculated change in weight;
the control unit further calculates a change in the center of gravity of the object during the modeling process, based on a discharge position on the placement table where the material is discharged from the modeling device and a weight of the material discharged at the discharge position; and
The machine tool device successively corrects the load value and center of gravity position of the mounting table in the moving device based on the calculated amount of change in weight and amount of change in center of gravity. The control unit
The machine tool apparatus according to claim 1 , wherein the weight is calculated based on a volume of the material discharged from the molding apparatus and a specific gravity of one material selected from a plurality of materials registered in advance. a purging means for purging the material remaining inside the modeling apparatus from the discharge nozzle;
a tray for receiving the material purged by the purging means;
The machine tool device according to claim 1, wherein the control unit, before performing modeling in the modeling device, moves the tray to the vicinity of the discharge nozzle using the moving device and performs an operation of receiving the material purged by the purging means in the tray. The tray is attached so as to be movable by the moving device,
4. The machine tool device according to claim 3, wherein the control unit moves the moving device to move the tray to the vicinity of the discharge nozzle, and further causes the material purged into the tray by the purging means to fall to a predetermined position. The machine tool device described in claim 4, wherein the tray is attached to the table and is moved by the moving device moving the table. a modeling device that discharges a material from a discharge nozzle to form a shape;
a mounting portion to which the modeling device is attached, the mounting portion being fixed in position in three-dimensional space;
a mounting table on which a model to be formed by receiving the material dispensed from the modeling device is placed;
a moving device that moves the mounting table in the space in accordance with a modeling program for forming the object;
a control unit that executes the modeling program,
Further provided is a wiping unit that wipes off the material adhering to the discharge nozzle,
the control unit causes the wiping unit to contact the discharge nozzle and executes a cleaning operation of the discharge nozzle before performing modeling in the modeling apparatus;
The wiping unit is attached so as to be movable by the moving device,
The control unit performs the cleaning operation by bringing the wiping unit into contact with the discharge nozzle with a force determined in the force mode of the moving device and moving the wiping unit in a direction different from the direction of the force. The machine tool device described in claim 6, wherein the wiping unit is attached to the stage and is moved by the moving device moving the stage. a modeling device that discharges a material from a discharge nozzle to form a shape;
a mounting portion to which the modeling device is attached, the mounting portion being fixed in position in three-dimensional space;
a mounting table on which a model to be formed by receiving the material dispensed from the modeling device is placed;
a moving device that moves the mounting table in the space in accordance with a modeling program for forming the object;
a control unit that executes the modeling program,
the control unit measures a gap between the discharge nozzle and the stage by bringing the discharge nozzle into contact with the stage in a manner that allows the discharge nozzle to be pressed against the stage with a determined force in a predetermined direction, before performing modeling in the modeling device;
The machine tool device corrects the horizontality of the mounting table based on the measured gap. The machine tool device described in claim 8, wherein the control unit checks the level of the stage by contacting the discharge nozzle with the stage at at least three points on the plane of the stage.