Numerical control devices and machine tools

Abstract

A numerical control device that controls, in accordance with a machining program, a machine tool that is equipped with a plurality of drive axes including a rotational positioning axis that rotationally positions a workpiece and a relative positioning axis that determines the relative position of the workpiece and a tool, and a clamping mechanism that clamps the rotational positioning axis, the numerical control device comprising: a priority axis memory unit that stores a correspondence relationship between the rotational positioning axis and a priority axis that is set as a drive axis that should be prioritized among the plurality of drive axes with respect to the rotational positioning axis; and a waiting control unit that, when a command to drive the rotational positioning axis and a command to drive the priority axis are given simultaneously, waits for the operation of the priority axis to be completed and then causes the clamping mechanism to clamp the rotational positioning axis.

Description

[Technical Field]

[0001] The present disclosure relates to a numerical control device and a machine tool. [Background technology]

[0002] Machine tools equipped with a rotary table device that rotates a table on which a workpiece is fixed are currently in use. The rotary table device rotates the table using a servo motor or the like to perform rotational positioning (indexing) of the table and the workpiece. Rotary table devices often include a clamping mechanism that clamps (holds in) a drive shaft (hereinafter referred to as the rotational positioning shaft) that maintains the indexed position of the table (see, for example, Patent Document 1).

[0003] Machine tools can be controlled according to a machining program. In some machining programs, the drive command for the rotary positioning axis and the clamping and unclamping commands for the clamping mechanism are written separately. However, in order to facilitate the creation of machining programs, many machine tools are configured so that, when a machining program contains a command to drive the rotary positioning axis, the numerical control device controls the rotary positioning axis and the clamping mechanism so that the clamping device releases (unclamps) the clamp before driving the rotary positioning axis, and the clamping device clamps the rotary positioning axis after the rotary positioning axis reaches the target rotation position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-168692 Summary of the Invention [Problem to be solved by the invention]

[0005] When a command to drive an axis that determines the relative position of the tool and workpiece and a command to drive an axis that rotationally positions the workpiece are simultaneously issued, i.e., when a rotational positioning command and a relative positioning command are written on the same line of a machining program, the unclamping, driving, and clamping of the rotational positioning axis and the driving of the relative positioning axis may occur simultaneously. However, the operation of the relative positioning axis may generate inertial forces that act as a force to rotate the rotational positioning axis due to, for example, a deviation of the workpiece's center of gravity from the rotational positioning axis. Therefore, if the rotational positioning axis is clamped without considering the operation of the relative positioning axis, the rotational position of the workpiece may be fixed at a position with a small error. Therefore, a technology that can accurately rotationally position a workpiece is desired. [Means for solving the problem]

[0006] A numerical control device according to one aspect of the present disclosure is a numerical control device that controls a machine tool according to a machining program, the machine tool having a rotational positioning axis that rotationally positions a workpiece, a relative positioning axis that determines the relative position of the workpiece and a tool, and a clamping mechanism that clamps the rotational positioning axis, and the clamping mechanism has a waiting control unit that, when a command to drive the rotational positioning axis and a command to drive a specified priority axis among the relative positioning axes are given simultaneously, waits for the operation of the priority axis to be completed before clamping the rotational positioning axis. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a machine tool according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of a machine tool 1 according to an embodiment of the present disclosure.

[0009] The machine tool 1 includes a rotational positioning axis Ab that rotationally positions a table 11 that holds a workpiece W, multiple relative positioning axes (X-axis Ax, Y-axis Ay, and Z-axis Az) that determine the relative positions of the workpiece W and tool T, and multiple drive axes including a spindle Ac that rotates and drives the tool T, a clamping mechanism 12 that clamps the rotational positioning axis Ab, and a numerical control device 20 that controls the rotational positioning axis Ab, the relative positioning axes Ax, Ay, and Az, spindle Ac, and clamping mechanism 12 in accordance with a machining program. The X-axis Ax is configured to move the rotational positioning axis Ab in a direction perpendicular to the axial direction of the rotational positioning axis Ab. The Y-axis Ay is configured to move the rotational positioning axis Ab in the axial direction of the rotational positioning axis Ab. The Z-axis Az is configured to move the spindle Ac in the axial direction of the spindle Ac. Although the machine tool 1 of this embodiment is configured to rotationally position the workpiece W (table 11) only by a single rotational positioning axis Ab, the machine tool according to the present disclosure may be configured to have multiple rotational positioning axes that rotationally position the table holding the workpiece around different axes.

[0010] The numerical control device 20 itself is one embodiment of the numerical control device according to the present disclosure. The numerical control device 20 may be realized by one or more computer devices having, for example, a memory, a processor, an input / output interface, etc., and executing an appropriate control program. The numerical control device 20 includes a priority axis storage unit 21, a priority axis setting unit 22, a waiting control unit 23, and a setting recommendation unit 24. Note that these components of the numerical control device 20 categorize the functions of the numerical control device 20 and do not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0011] The priority axis storage unit 21 stores the correspondence between a rotational positioning axis and a priority axis that is set as a drive axis that should be prioritized among multiple drive axes for that rotational positioning axis. For example, the priority axis storage unit 21 can store data as a matrix (table) that defines whether all drive axes are priority axes for each rotational positioning axis.

[0012] The priority axis is preferably a relative positioning axis that moves the driven rotational positioning axis in a direction different from the axial direction of the rotational positioning axis. In the machine tool 1 of this embodiment, when the X-axis Ax is driven, a positioning error of the rotational positioning axis Ab may occur due to inertial force caused by eccentricity of the center of gravity of the workpiece W with respect to the rotational positioning axis Ab. Therefore, it is preferable to set at least the X-axis Ax as the priority axis with respect to the rotational positioning axis Ab. Furthermore, when there are multiple rotational positioning axes, the other rotational positioning axes may be set as priority axes with respect to each rotational positioning axis.

[0013] The priority axis setting unit 22 provides a user interface that allows the user to store the priority axis in the priority axis memory unit. Whether or not a positioning error occurs in the rotational positioning axis Ab due to the influence of the other drive axes Ax, Ay, and Az depends on the shape and mass of the workpiece W, etc., so by allowing the user to set a priority axis as needed, it is possible to prevent positioning errors in the workpiece W while suppressing increases in machining time. The priority axis setting unit 22 may be configured so that the user selects a priority axis from among preset candidates. By excluding drive axes that are unlikely to cause rotational positioning errors in advance, it is possible to suppress setting errors. For this reason, the priority axis memory unit 21 may store information on whether or not each drive axis can be set as a priority axis.

[0014] When a command to drive the rotational positioning axis Ab and a command to drive the priority axis Ax are given simultaneously, the queuing control unit 23 waits for the operation of the priority axis Ax to be completed before causing the clamping mechanism 12 to clamp the rotational positioning axis Ab. In other words, if rotational positioning by the rotational positioning axis Ab is completed before the operation of the corresponding priority axis Ax is completed, the rotational positioning axis Ab is servo-driven to maintain the target rotational position until the operation of the priority axis Ax is completed, and the servo driving ends after clamping by the clamping mechanism 12. Naturally, if rotational positioning by the rotational positioning axis Ab is completed after the operation of the corresponding priority axis Ax is completed, clamping by the clamping mechanism 12 is performed immediately after completion of rotational positioning.

[0015] If an error equal to or greater than a predetermined standard occurs in the rotational positioning axis Ab when a command to drive the rotational positioning axis Ab and commands to drive the other drive axes Ax, Ay, and Az are simultaneously executed, the setting recommendation unit 24 issues a notification recommending setting one of the other drive axes Ax, Ay, and Az as the priority axis. Whether a positioning error occurs in the rotational positioning axis Ab due to the influence of the other drive axes Ax, Ay, and Az varies depending on the workpiece W, and it is not easy to appropriately determine in advance whether or not a priority axis needs to be set. For this reason, the numerical control device 20 determines whether or not a priority axis needs to be set based on feedback from the rotational positioning axis Ab and recommends setting a priority axis to the user as necessary, thereby reducing the burden on the user of determining whether or not the priority axis setting is appropriate.

[0016] As described above, when a command to drive the rotational positioning axis Ab and a command to drive the priority axis Ax are given simultaneously, the machine tool 1 is equipped with a waiting control unit 23 that waits for the operation of the priority axis Ax to be completed and then causes the clamping mechanism 12 to clamp the rotational positioning axis Ab, thereby enabling the workpiece W to be rotationally positioned relatively accurately.

[0017] The following additional notes are provided regarding the above-described embodiment and modifications. (Appendix 1) The numerical control device (20) controls, in accordance with a machining program, a machine tool (1) equipped with a plurality of drive axes including a rotational positioning axis (Ab) for rotationally positioning a workpiece (W) and relative positioning axes (Ax, Ay, Az) for determining the relative position of the workpiece (W) and a tool (T), and a clamping mechanism (12) for clamping the rotational positioning axis (Ab). The numerical control device (20) is equipped with a priority axis memory unit (21) for storing the correspondence between the rotational positioning axis (Ab) and a priority axis (Ax) that is set as a drive axis that should have priority among the plurality of drive axes with respect to the rotational positioning axis (Ab), and a waiting control unit (23) that, when a command to drive the rotational positioning axis (Ab) and a command to drive the priority axis (Ax) are given simultaneously, waits for the operation of the priority axis (Ax) to be completed and causes the clamping mechanism (12) to clamp the rotational positioning axis (Ab).

[0018] (Appendix 2) In the numerical control device (20) of Supplementary Note 1, the priority axis (Ax) may be a relative positioning axis that moves the driven rotational positioning axis (Ab) in a direction different from the axial direction of the rotational positioning axis (Ab).

[0019] (Appendix 3) The numerical control device (20) of Supplementary Note 1 or 2 may further include a priority axis setting unit (22) that allows a user to store a priority axis (Ax) in the priority axis storage unit (21).

[0020] (Appendix 4) In the numerical control device (20) of Supplementary Note 3, the priority axis setting unit (22) may be configured so that the user selects the priority axis (Ax) from among preset candidates.

[0021] (Appendix 5) The numerical control device (20) of Supplementary Notes 1 to 4 may further include a setting recommendation unit (24) that, when an error equal to or greater than a predetermined standard occurs in the rotational positioning axis (Ab) when a command to drive the rotational positioning axis (Ab) and a command to drive the other drive axes (Ax, Ay, Az) are executed simultaneously, issues a notification recommending setting one of the other drive axes (Ax, Ay, Az) as the priority axis (Ax).

[0022] (Appendix 6) The machine tool (1) includes a plurality of drive axes including a rotational positioning axis (Ab) that rotates and positions the workpiece (W) and relative positioning axes (Ax, Ay, Az) that determine the relative position of the workpiece (W) and the tool (T), a clamping mechanism (12) that clamps the rotational positioning axis (Ab), and a numerical control device (20) described in appendices 1 to 5 that controls the rotational positioning axis (Ab), the relative positioning axis, and the clamping mechanism (12).

[0023] Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of each operation and each process in the above-described embodiments is shown as an example and is not limited to these. The same applies when numerical values ​​or formulas are used in the description of the above-described embodiments. For example, in the numerical control device according to the present disclosure, the priority axis setting unit and the setting recommendation unit are not essential components. [Explanation of symbols]

[0024] 1 Machine tools 11 tables 12 Clamping mechanism 20 Numerical Control Device 21 Priority axis storage 22 Priority axis setting section 23 Waiting control section 24 Recommended Settings Ab Rotational Positioning Axis Ax, Ay, Az relative positioning axes T Tool double work

Claims

1. A numerical control device that controls a machine tool according to a machining program, the machine tool including a plurality of drive axes including a rotational positioning axis that rotates and positions a workpiece and a relative positioning axis that determines a relative position between the workpiece and a tool, and a clamping mechanism that clamps the rotational positioning axis, a priority axis storage unit that stores a correspondence relationship between the rotational positioning axis and a priority axis that is set as a drive axis that should be prioritized among the plurality of drive axes with respect to the rotational positioning axis; a waiting control unit that, when a command to drive the rotational positioning axis and a command to drive the priority axis are given simultaneously, waits for the operation of the priority axis to be completed before causing the clamp mechanism to clamp the rotational positioning axis; Equipped with The priority axis is the relative positioning axis that moves the driven rotational positioning axis in a direction different from the axial direction of the rotational positioning axis.

2. The numerical control device according to claim 1 , further comprising a priority axis setting unit that allows a user to store the priority axis in the priority axis storage unit.

3. The numerical control device according to claim 2 , wherein the priority axis setting unit is configured so that a user can select the priority axis from among preset candidates.

4. 4. The numerical control device according to claim 1, further comprising a setting recommendation unit that, when an error equal to or greater than a predetermined standard occurs in the rotational positioning axis when a command to drive the rotational positioning axis and a command to drive another of the drive axes are executed simultaneously, issues a notification recommending setting one of the other of the drive axes as the priority axis.

5. a plurality of drive axes including a rotation positioning axis for rotationally positioning a workpiece and a relative positioning axis for determining the relative positions of the workpiece and a tool; a clamping mechanism that clamps the rotation positioning shaft; a numerical control device according to any one of claims 1 to 3, which controls the plurality of drive shafts and the clamping mechanism; A machine tool equipped with:

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