Numerical Control Device

Abstract

To provide a numerical control device capable of easily and surely performing a trial run in which a tool does not interfere with a work.SOLUTION: The numerical control device according to one aspect of the present disclosure is a numerical control device that controls a machine tool for machining a work with a tool according to a machining program, including: an offset setting unit that determines, for each tool, an offset direction and an offset amount based on the orientation of the tool; a trial run path calculation unit for calculating a moving path for trial run of the tool that is offset by the offset amount in the offset direction from a moving path for machining the tool specified by the machining program; and an operation mode selection unit for selecting either a machining operation mode in which the tool is moved along the moving path for machining or a test run mode in which the tool is moved along the moving path for trial run.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a numerical control device. [Background technology]

[0002] Machining systems that include a machine tool for machining a workpiece and a numerical control device for controlling the machine tool according to a machining program are widely used. In such machining systems, before actually machining a workpiece, the machine tool may be operated on a trial basis to check whether the machining program is appropriate, by moving the tool to a position where it will not act on (contact) the workpiece.

[0003] Generally, by temporarily changing the tool length setting (the distance between the chuck and the cutting edge), the tool can be moved back from the position specified by the machining program to prevent interference with the workpiece. However, depending on the type of tool, the cutting direction of the tool differs from the direction connecting the chuck and the cutting edge, so changing the tool length setting may not prevent the tool from interfering with the workpiece. Furthermore, after changing the tool length setting and performing a test run, it is necessary to return the tool length setting to the appropriate value. However, forgetting to do this or setting the tool length setting to an incorrect value may result in inappropriate machining.

[0004] In order to facilitate test runs of machine tools, a numerical control device has been proposed which includes a movement amount calculation means for calculating a movement amount, which is the difference between a movement start position and a movement end position, for each of one or more cutting operations performed in accordance with cutting instructions in a machining program, and an offset amount determination means for determining the largest movement amount among the movement amounts calculated by the movement amount calculation means as the offset amount (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4867876 Summary of the Invention [Problem to be solved by the invention]

[0006] In the method described in Patent Document 1, the longest distance among the Z-axis movement amounts is used as the tool offset amount (the amount of back movement from the position according to the machining program). However, with this method, there is a risk that it will not be possible to appropriately avoid interference of the tool with the workpiece in machine tools that perform complex operations, such as five-axis machining centers. For this reason, there is a demand for a numerical control device that can easily and reliably perform test runs that do not cause the tool to interfere with the workpiece. [Means for solving the problem]

[0007] A numerical control device according to one aspect of the present disclosure is a numerical control device that controls a machine tool that machines a workpiece with a tool in accordance with a machining program, and includes: an offset setting unit that determines, for each tool, an offset direction and offset amount based on the orientation of the tool; a trial run path calculation unit that calculates a trial run movement path of the tool that is offset in the offset direction by the offset amount from the machining movement path of the tool specified by the machining program; and an operation mode selection unit that selects either a machining operation mode in which the tool is moved along the machining movement path, or a trial run mode in which the tool is moved along the trial run movement path. [Effects of the Invention]

[0008] According to the numerical control device of the present disclosure, a test run can be easily and reliably performed without causing the tool to interfere with the workpiece. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating a configuration of a machining system including a numerical control device according to an embodiment of the present disclosure. [Figure 2]2 is a schematic diagram showing offsets when a tool is a ball end mill in the machining system of FIG. 1. FIG. [Figure 3] 2 is a schematic diagram showing offsets when the tool in the machining system of FIG. 1 is a side milling cutter. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present disclosure will be described below with reference to the accompanying drawings, in which: Fig. 1 is a schematic diagram showing the configuration of a machining system 100 including a machine tool 1 and a numerical control device 2 according to an embodiment of the present disclosure.

[0011] Machine tool 1 is a device that cuts workpiece W by applying tool T, which is rotated by spindle Am, to workpiece W. Machine tool 1 can be, for example, a device that cuts workpiece W held on table B using tool T held in machining head H, and has multiple drive axes that can move tool T (machining head H) relative to workpiece W (table B). The specific axis configuration of machine tool 1 is not particularly limited, but as an example, machine tool 1 can be a five-axis machine that has, as multiple drive axes, linear axes Ax, Ay, and Az in orthogonal x, y, and z directions, a rotational axis Ab parallel to linear axis Ay, and a rotational axis Ac parallel to linear axis Az.

[0012] The numerical control device 2 controls the spindle Am and drive axes Ax, Ay, Az, Ab, and Ac of the machine tool 1 in accordance with a machining program. This numerical control device 2 can be realized by causing a computer device having, for example, a CPU, memory, an input / output interface, etc. to execute an appropriate control program. The numerical control device 2 may be configured to communicate with a management server that manages multiple machining systems 100.

[0013] The numerical control device 2 includes a program storage unit 21, a coordinate system storage unit 22, a tool data storage unit 23, a machining path calculation unit 24, an offset setting unit 25, a test operation path calculation unit 26, an operation mode selection unit 27, and an operation control unit 28. Note that these components are functionally distinct, and do not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0014] The program storage unit 21 stores a machining program. The program storage unit 21 may be configured to store a plurality of machining programs and select a machining program instructed by a user or a management server from the plurality of stored machining programs. The configuration of the program storage unit 21 may be the same as that of a conventional numerical control device.

[0015] The coordinate system storage unit 22 stores the coordinate system of the workpiece W. This enables the numerical control device 2 to convert between the coordinate system of the machine tool 1 and the coordinate system of the workpiece W. The configuration of the coordinate system storage unit 22 can be the same as that of a conventional numerical control device.

[0016] The tool data storage unit 23 stores information about the tool T necessary for machining the workpiece W, such as the type of tool T, blade length, and appropriate cutting speed range. The tool data storage unit 23 may store numerical values ​​of the offset direction and offset amount that are directly adopted in the offset setting unit 25 described later. Specifically, the tool data storage unit 23 can be configured to store a table that associates the numbers or IDs of multiple tools T with multiple pieces of information necessary for machining.

[0017] The machining path calculation unit 24 calculates a movement path of the tool T in accordance with the machining program stored in the program storage unit 21. Specifically, the machining path calculation unit 24 analyzes the machining program and calculates the position and posture of the tool T at each time specified by the machining program, and further calculates the positions of the drive axes Ax, Ay, Az, Ab, and Ac at each time to realize the position and posture.

[0018] The offset setting unit 25 has an offset direction determination unit 251 that determines, for each tool T, an offset direction Dd, which is the direction in which the tool T is retracted from the machining movement path during a trial run, based on the orientation of the tool T (in this embodiment, the orientation of the rotation axis that coincides with the spindle Am), and an offset amount determination unit 252 that determines an offset amount Da, which is the distance in which the tool T is retracted from the machining movement path.

[0019] The offset direction determination unit 251 sets the offset direction stored in the tool data storage unit 23 for the currently used tool T as the offset direction of that tool T. Furthermore, if no offset direction is stored in the tool data storage unit 23, the offset direction may be set to the rotation axis direction of the tool T (the direction of the spindle Am). Since offsetting in the rotation axis direction is appropriate for many tools T, if the offset direction is the rotation axis direction, the input can be omitted, thereby improving user convenience.

[0020] The offset direction determination unit 251 may determine the offset direction Dd of the tool T depending on the type of the tool T. In other words, the offset direction determination unit 251 may be configured to determine the offset direction Dd of the tool T depending on the type of the tool T stored in the tool data storage unit 23. For this reason, the offset direction determination unit 251 may store a table indicating the relationship between the type of the tool T and the offset direction Dd.

[0021] As a specific example, when the tool T is a ball end mill as shown in Fig. 2, the offset direction determination unit 251 preferably sets the offset direction Dd to the direction of the rotation axis (i.e., the main axis Am) of the tool T. In particular, when the machine tool 1 is a five-axis machining center and the tool T is a ball end mill, there is a risk that the tool T will interfere with the workpiece W even if the tool T is offset in the z direction along the vertical linear axis Az, as shown on the left side of the figure. Therefore, by offsetting the tool T in the direction of the rotation axis (Am) of the tool T, as shown on the right side of the figure, it is possible to prevent the tool T from interfering with the workpiece W.

[0022] 3, when the tool T is a face mill, the offset direction determination unit 251 preferably sets the offset direction Dd to a direction perpendicular to the rotation axis (Am) of the tool T. When the tool T is a face mill, as shown on the left side of the figure, there is a risk that the tool T will interfere with the workpiece even if the tool T is offset in the direction of the rotation axis (Am) of the tool T. Therefore, as shown on the right side of the figure, by offsetting the tool T in a direction perpendicular to the rotation axis (Am) of the tool T, it is possible to prevent the tool T from interfering with the workpiece W.

[0023] The offset amount determination unit 252 may analyze the machining program to calculate the cutting amount and set the offset amount Da of the tool T to a value equal to or greater than the cutting amount, or may determine the offset amount Da of the tool T according to the blade length of the tool T. Specifically, the offset amount determination unit 252 can set the offset amount Da to the blade length of the tool T or a value obtained by multiplying the blade length by a predetermined coefficient (safety factor). In machining with a single cutting pass, such as finish machining, the cutting amount of the tool T cannot be set to be greater than or equal to the blade length, so the cutting amount of the tool T is set to be less than or equal to the blade length of the tool T in the machining program. For this reason, if the offset amount is set to be greater than or equal to the blade length of the tool T, it is possible to prevent the tool T from interfering with the workpiece W.

[0024] The trial operation path calculation unit 26 calculates a trial operation movement path of the tool T that is offset from the machining movement path calculated by the machining path calculation unit 24 in the offset direction Dd determined by the offset setting unit 25 by the offset amount Da determined by the offset setting unit 25. The trial operation path calculation unit 26 determines the offset direction Dd of the machining movement path for each time based on the posture of the tool T for each time specified by the machining path calculation unit 24. This allows the optimal offset direction Dd to be selected depending on the posture of the tool T, making it possible to reliably prevent interference of the tool T with the workpiece W during the trial operation.

[0025] The operation mode selection unit 27 selects either a machining operation mode in which the tool T is moved along the machining movement path calculated by the machining path calculation unit 24 to machine the workpiece W, or a trial operation mode in which the tool T is moved along the trial operation movement path calculated by the trial operation path calculation unit 26 so as not to come into contact with the workpiece W. This makes it possible to easily switch between a trial operation in which the tool T is moved with an offset so as not to come into contact with the workpiece W, and a machining operation in which the tool T cuts the workpiece W, without performing work such as changing setting values.

[0026] The operation control unit 28 generates a command signal to be input to the machine tool 1 so as to move the tool T along the machining movement path calculated by the machining path calculation unit 24 to machine the workpiece W, or to perform a trial run in which the tool T is moved along the trial run movement path calculated by the trial run path calculation unit 26 without coming into contact with the workpiece W. The configuration of the operation control unit 28 can be the same as that of a conventional numerical control device.

[0027] In the numerical control device 2, the offset setting unit 25 determines the offset direction Dd for each tool T based on the orientation of the tool T, so that a test run can be performed while appropriately preventing interference of the tool T with the workpiece W. Furthermore, since the offset setting unit 25 determines the offset amount Da according to the tool T, the offset amount Da for the tool T can be set to the minimum necessary size, so that the suitability of the machining program can be more easily confirmed.

[0028] Although the embodiments of the numerical control device according to the present disclosure have been described above, the numerical control device according to the present disclosure is not limited to the above-described embodiments. Furthermore, the effects described in the above-described embodiments are merely a list of the most favorable effects that can be obtained from the numerical control device according to the present disclosure, and the effects of the numerical control device according to the present disclosure are not limited to those described in the above-described embodiments.

[0029] The numerical control device according to the present disclosure may be configured such that the machining path calculation unit and the trial operation path calculation unit are connected in series, and the operation mode selection unit enables or disables the function of the trial operation path calculation unit, thereby allowing the trial operation path calculation unit to select whether to output a trial operation movement path that is an offset from the machining movement path calculated by the machining path calculation unit, or whether the trial operation path calculation unit outputs the machining movement path calculated by the machining path calculation unit as is.

[0030] The numerical control device according to the present disclosure may be used to control a machine tool that performs machining other than milling, such as turning. [Explanation of symbols]

[0031] 1. Numerical control device 21 Program memory section 22 Coordinate system storage section 23 Tool data storage unit 24 Machining path calculation unit 25 Offset setting section 26 Test run route calculation section 27 Operation mode selection section 28 Operation control unit 251 Offset direction determination unit 252 offset amount determination unit 100 Processing System T-tool double work

Claims

1. A numerical control device that controls a machine tool that processes a workpiece using a tool in accordance with a processing program, an offset setting unit that determines an offset direction and an offset amount based on the orientation of the tool for each of the tools; a test run path calculation unit that calculates a test run movement path of the tool that is offset by the offset amount in the offset direction from the machining movement path of the tool specified by the machining program; an operation mode selection unit that selects either a machining operation mode in which the tool is moved along the machining movement path or a trial operation mode in which the tool is moved along the trial operation movement path; Equipped with The offset setting unit is a numerical control device that determines the offset direction depending on the type of the tool.

2. The numerical control device according to claim 1 , wherein the offset setting unit determines the offset amount in accordance with a cutting edge length of the tool.

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