WO2024069951A1

WO2024069951A1 - Machine tool control device and machine tool display device

Info

Publication number: WO2024069951A1
Application number: PCT/JP2022/036751
Authority: WO
Inventors: 将司安田
Original assignee: ファナック株式会社
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2024-04-04
Also published as: JP7252426B1

Abstract

Provided is the technology that enables accurate assessment as to whether chip shredding is possible in oscillation cutting, even if machining conditions change, and that also facilitates adjustment of the machining conditions. A machine tool control device 1 comprises: a condition acquisition unit 11 that acquires, as preconditions, one or two items of information from among three items of information that are a feed amount F, an oscillation frequency multiplier I, and an oscillation amplitude multiplier K; an air cut amount acquisition unit 12 that acquires a designated air cut amount that indicates the degree of air cutting in a direction of oscillation; and a machining control unit 13 that, on the basis of the preconditions, determines the item(s) of information among the three items of information not acquired by the condition acquisition unit 11 so that an air cut amount based on an amount between n rotation passes and rotation passes subsequent to n rotations will be a designated air cut amount and performs machining control.

Description

Machine tool control device and machine tool display device

This disclosure relates to a control device for a machine tool and a display device for a machine tool.

　Conventionally, the workpiece is machined by oscillating the tool and workpiece relative to each other to prevent chips that are continuously generated during machining from becoming entangled in the workpiece or cutting tool, which can lead to machining defects or machine failures.

In this type of oscillating machining, a technique is known in which the tool path, which is the trajectory of the tool, is set to overlap partially with the previous tool path, causing the tool to leave the surface of the workpiece, creating an air cut and shredding the chips (see, for example, Patent Documents 1 and 2).

JP 2018-094690 A JP 2020-009248 A

In cutting, the amplitude magnification is often determined by the ratio of the amplitude to the feed rate of the tool per revolution of the spindle. In setting the amplitude magnification, in order to ensure that air cuts occur, a value with a small margin is used rather than being set to the limit at which air cuts occur. For example, even if an air cut would theoretically occur at an amplitude magnification of 1.0, machining was performed with a margin set at an amplitude magnification of 1.2.

However, in the method of determining the oscillation amplitude based on the amplitude magnification, even with the same amplitude magnification, differences in the feed speed affect whether chips can be shredded. Also, in taper machining, even if the feed speed is constant, if the taper angle is large, the feed speed in the oscillation direction becomes slower, which affects whether chips can be shredded or not, making it difficult to adjust the machining conditions.

Also, the amplitude multiplier value required to achieve chip shredding changes depending on the frequency multiplier setting, which is the number of oscillations per rotation of the spindle. This makes it difficult to understand how to set the amplitude multiplier in relation to whether chip shredding is possible, and makes it difficult to adjust the processing conditions.

This disclosure has been made in consideration of the above problems, and aims to provide technology that can accurately determine whether chip shredding is possible even when processing conditions change during oscillating cutting, and also makes it easy to adjust processing conditions.

The present disclosure relates to a control device for a machine tool that performs machining while oscillating a cutting tool and a workpiece relative to one another, the control device for a machine tool including: a condition acquisition unit that acquires, as a precondition, one or two pieces of information out of three pieces of information: information on the relative feed amount per rotation between the cutting tool and the workpiece; information on the relative number of oscillations per rotation between the cutting tool and the workpiece; and information on the oscillation amplitude for the relative feed amount per rotation between the cutting tool and the workpiece; an air cut amount acquisition unit that acquires a designated air cut amount that indicates the degree of air cut in the oscillation direction; and a machining control unit that determines, based on the precondition, the information out of the three pieces of information that has not been acquired by the condition acquisition unit, so that the air cut amount based on the gap between a pass of n rotations and a pass of a rotation later than n rotations becomes the designated air cut amount, and performs machining control.

The present disclosure also provides a display device for a machine tool that performs machining while oscillating a cutting tool and a workpiece relative to one another, the display device for the machine tool including: a condition input unit that accepts input of one or two pieces of information as preconditions out of three pieces of information: information on the relative feed rate per rotation between the cutting tool and the workpiece; information on the relative number of oscillations per rotation between the cutting tool and the workpiece; and information on the oscillation amplitude for the relative feed rate per rotation between the cutting tool and the workpiece; an air cut amount input unit that accepts input of a designated air cut amount that indicates the degree of air cut in the oscillation direction; an information calculation unit that calculates, based on the preconditions, the information out of the three pieces of information that has not been acquired by the condition acquisition unit so that the air cut amount based on the gap between the pass of n rotations and the pass of a rotation later than n rotations becomes the designated air cut amount; and a display unit that displays the information calculated by the information calculation unit.

This disclosure provides technology that can accurately determine whether chip shredding is possible even when processing conditions change during oscillating cutting, and also makes it easy to adjust processing conditions.

FIG. 13 is a diagram for explaining swing cutting. FIG. 2 is a functional block diagram of the control device for the machine tool according to the first embodiment. 3 is a block diagram showing conditions acquired by a condition acquisition unit in the first embodiment; FIG. FIG. 4 is a diagram showing an example of a machining program. FIG. 2 is a diagram illustrating a schematic positional relationship between a workpiece and a cutting tool. FIG. 11 is a block diagram showing conditions acquired by a condition acquisition unit according to the second embodiment. FIG. 13 is a diagram illustrating a schematic positional relationship between a workpiece and a cutting tool when the taper angle is small. FIG. 13 is a diagram illustrating a schematic positional relationship between a workpiece and a cutting tool when the taper angle is large. FIG. 13 is a block diagram showing conditions acquired by a condition acquisition unit according to the third embodiment. FIG. 11 is a functional block diagram of a display device of a machine tool according to a modified example.

The following describes in detail the embodiments of the present disclosure with reference to the drawings.

[First embodiment]
A control device 1 for a machine tool according to a first embodiment of the present invention is for performing swing cutting, which cuts (turns) a workpiece while swinging a cutting tool and the workpiece relatively. First, swing cutting will be described with reference to FIG.

FIG. 1 is a diagram for explaining oscillating cutting. In one example of oscillating cutting shown in FIG. 1, at least one spindle S that rotates the cutting tool T and the workpiece W relative to each other and at least one feed axis (not shown) that moves the cutting tool T relative to the workpiece W are operated to rotate the cutting tool T and the workpiece W relative to each other and to perform cutting while oscillating the cutting tool T and the workpiece W relative to each other in the feed direction. At this time, the tool path, which is the trajectory of the cutting tool T, is set so that the current path partially overlaps with the previous path. In other words, the current path partially includes the part that has been machined in the previous path, generating an air cut called an air cut, in which the cutting edge of the cutting tool T separates from the surface of the workpiece W, and the cutting chips are chopped up.

In addition, the shape of the workpiece is not limited in the oscillating cutting performed in this embodiment. In other words, it can be applied even when the workpiece has a tapered portion or an arc-shaped portion on the machining surface, requiring multiple feed axes (Z axis and X axis), or when the workpiece is cylindrical or cylindrical and only one specific feed axis (Z axis) is sufficient.

Next, the configuration of the machine tool control device 1 will be described. FIG. 2 is a functional block diagram of the machine tool control device 1 according to one embodiment of the present invention. The machine tool control device 1 of this embodiment is configured using a computer equipped with memories such as a ROM (read only memory) and a RAM (random access memory), a CPU (control processing unit), and a communication control unit, which are connected to each other via a bus. The functions and operations of each of the above functional units are achieved by the cooperation of the CPU, memory, and control programs stored in the memory mounted on the computer. The machine tool control device 1 may also be configured with a CNC (Computer Numerical Controller) or a PLC (Programmable Logic Controller), or may be connected to a higher-level computer that outputs machining conditions such as rotation speed in addition to machining programs. For convenience, FIG. 2 shows only a motor 3 that drives one feed axis.

As shown in FIG. 2, the machine tool control device 1 includes a condition acquisition unit 11, an air cut amount acquisition unit 12, a machining control unit 13, a memory unit 14, an input unit 15, and a display unit 16.

The condition acquisition unit 11 acquires the machining conditions and the oscillation conditions for oscillating the workpiece W. The machining conditions and the oscillation conditions may be, for example, those stored in the memory unit 14, or may be those output from an external computer.

The machining conditions include at least information regarding the relative feed rate per revolution between the cutting tool and the workpiece, and information regarding the shape of the cutting tool cutting edge, as well as information regarding, for example, the spindle rotation speed S (1/min), the feed rate of the cutting tool (mm/min), the workpiece diameter (mm), the clearance angle of the cutting tool (°), etc. Examples of information regarding the relative feed rate per revolution between the cutting tool and the workpiece include the feed rate per revolution F (mm/rev) and a combination of the spindle rotation speed S (1/min) and the feed rate of the cutting tool (mm/min), and examples of information regarding the shape of the cutting tool cutting edge include the radius of the cutting edge (mm).

The oscillation conditions include information on the relative oscillation number per revolution between the cutting tool and the workpiece, and information on the oscillation amplitude relative to the feed amount per revolution between the cutting tool and the workpiece. Information on the relative oscillation number per revolution between the cutting tool and the workpiece includes an oscillation frequency magnification I (times), which indicates the oscillation frequency per revolution of the spindle. Information on the oscillation amplitude relative to the relative feed amount per revolution between the cutting tool and the workpiece includes an oscillation amplitude magnification K (times), which indicates the magnitude of the oscillation amplitude relative to the magnitude of the feed amount per revolution of the spindle. The oscillation frequency magnification I (times) may be specified directly, or may be calculated from the oscillation frequency (Hz) and the spindle rotation speed S (1/min) after specifying the oscillation frequency (Hz). Similarly, the oscillation amplitude magnification K (times) may be specified directly, or may be calculated from the oscillation amplitude (mm), the feed rate (mm/min), and the spindle rotation speed S (1/min) after specifying the oscillation amplitude (mm).

The air cut amount acquisition unit 12 acquires a specified air cut amount that is specified in advance by an operator or the like. The air cut amount may be, for example, stored in the memory unit 14, may be acquired from an external computer, or may be input via the input unit 15.

The air cut amount referred to here is the amount of air cut between the pass at the nth rotation and the pass at a rotation later than the nth rotation (n+1 or later rotations). In this embodiment, the amount of air cut between the pass at the nth rotation and the pass at the n+1th rotation is used to determine the machining conditions, but this is not limited to this. For example, the amount of air cut between the pass at the nth rotation and the pass at the n+2th rotation may be used to determine the machining conditions.

In this embodiment, the air cut amount is the distance in the oscillation direction. In this embodiment, the feed axis oscillates in the feed direction, so the air cut amount is a numerical value that indicates the degree of air cut in the feed direction. The air cut amount only needs to be an index that indicates the magnitude of the air cut, and may be expressed as the distance in the oscillation direction, an area including the oscillation direction, a level linked to the air cut amount previously determined in a table, or a multiplication factor relative to an arbitrary reference value (for example, the workpiece diameter or the feed amount).

The machining control unit 13 controls machining based on the conditions acquired by the condition acquisition unit 11 so that the air cut amount after machining starts becomes the designated air cut amount. Details of machining control by the machining control unit 13 will be described later.

The memory unit 14 stores various information for controlling and machining the machine tool. In this embodiment, the memory unit 14 stores the machining conditions, oscillation conditions, and air cut amount specified by the operator. The machining conditions, oscillation conditions, and air cut amount are, for example, input by the operator into the machining program or specified as machine tool parameters. Note that the memory unit 14 may be configured to be located outside the control device 1 instead of inside it.

The input unit 15 inputs information related to processing in response to an operator's input operation on an input means (not shown), such as a keyboard or a touch panel. The information related to processing input by the input unit 15 is stored in the memory unit 10, etc., or input to each part of the control device 1.

The display unit 16 displays various information related to the machine tool, the control device 1, and processing.

Next, the conditions acquired by the condition acquisition unit 11 and the processing control by the processing control unit 13 will be described with reference to FIG. 3. FIG. 3 is a block diagram showing the conditions acquired by the condition acquisition unit 11 in the first embodiment.

As shown in FIG. 3, the condition acquisition unit 11 includes a frequency multiplication factor acquisition unit 21 and a feed amount acquisition unit 22. The frequency multiplication factor acquisition unit 21 is an oscillation number acquisition unit that acquires information regarding the relative oscillation number per rotation between the cutting tool and the workpiece, and acquires the oscillation frequency multiplication factor I (times) as information regarding the oscillation number. The feed amount acquisition unit 22 acquires the spindle feed amount F (mm/rev) per rotation as information regarding the relative feed amount per rotation between the cutting tool and the workpiece.

4 is a diagram showing an example of a machining program, which is generated by an operator specifying various information via the input unit 15 or the like.
In the machining program of Figure 4, the block "S2000 M03" is a description that indicates that the spindle is to rotate in the forward direction. The block "G8.5 P2 I0.5 L0.02" describes "I0.5" that indicates the frequency multiplication factor and "L0.02" that indicates the specified air cut amount. "F0.1" in the block "G01 Z20.F0.1" is a description that indicates the feed amount.

When machining operation is started, the condition acquisition unit 11 of the control device 1 acquires the frequency multiplier and feed amount from the machining program, and the air cut amount acquisition unit 12 acquires the specified air cut amount. In the example of Figure 4, the condition acquisition unit 11 acquires the frequency multiplier of 0.5 [times] from "I0.5" and the feed amount per revolution of 0.1 [mm/rev] from "F0.1". In addition, the air cut amount acquisition unit 12 acquires the specified air cut amount of 0.02 [mm] from "L0.02".

The machining control unit 13 determines the oscillation amplitude for performing the oscillation cutting process using the following formula based on the frequency multiplier and feed amount, which are the conditions acquired by the condition acquisition unit 11, and the specified air cut amount acquired by the air cut amount acquisition unit 12. In this example, the frequency multiplier 0.5 [times], the feed amount per revolution 0.1 [mm/rev], and the specified air cut amount = 0.02 [mm] are substituted.

In formula (1), I represents the frequency multiplication factor [times], F represents the feed rate per revolution [mm/rev], L represents the specified air cut amount [mm], A represents the oscillation amplitude [mm], and θ represents the phase of the workpiece [°] at which the air cut amount becomes L.

FIG. 5 is a diagram showing a schematic diagram of the positional relationship between the workpiece W and the cutting tool T. As shown in FIG. 5, the machining control unit 13 performs oscillating cutting based on the oscillating amplitude A calculated using formula (1) so that the air cut amount between the previous pass, which is the nth cutting pass, and the current pass, which is the (n+1)th cutting pass, becomes the specified air cut amount.

The processing control unit 13 outputs information indicating the calculated oscillation amplitude to the display unit 16. The display unit 16 communicates the oscillation amplitude to the operator by text information, graphic information, or a combination thereof indicating the oscillation amplitude.

The control device 1 for a machine tool that performs machining while oscillating the cutting tool T and the workpiece W relative to one another according to the first embodiment described above provides the following effects.

The control device 1 of the machine tool according to this embodiment includes a condition acquisition unit 11 that acquires one or two pieces of information as preconditions out of three pieces of information: information on the relative feed rate per revolution between the cutting tool T and the workpiece W (e.g., feed rate F), information on the relative number of oscillations per revolution between the cutting tool T and the workpiece W (e.g., oscillation frequency magnification I), and information on the oscillation amplitude for the relative feed rate per revolution between the cutting tool T and the workpiece (e.g., oscillation amplitude magnification K); an air cut amount acquisition unit 12 that acquires a designated air cut amount indicating the degree of air cut in the oscillation direction; and a machining control unit 13 that determines the information among the three pieces of information that the condition acquisition unit 11 has not acquired based on preconditions so that the air cut amount based on the gap between the n-rotation pass and the rotation pass after the n-rotation becomes the designated air cut amount, and performs machining control. As a result, since the target designated air cut amount is set, even if the machining conditions change in the oscillation cutting process, it is possible to accurately determine whether chip shredding is possible, and it is also easy to adjust the machining conditions.

In addition, the condition acquisition unit 11 of this embodiment acquires the information on the feed amount and the information on the oscillation number as preconditions among the three pieces of information, and the processing control unit 13 determines the information on the oscillation amplitude based on the information on the feed amount and the information on the oscillation number so that the air cut amount based on the gap between the pass of n rotations and the pass of the rotation (n+1 rotations) after the n rotations becomes the specified air cut amount. In the method of determining the oscillation amplitude by setting the oscillation amplitude magnification as in the conventional technology, even with the same amplitude magnification, the possibility of chip shredding changes depending on the feed speed. For example, when the frequency magnification is 0.5 [times], the amplitude magnification is 1.2 [times], and the feed amount is 0.04 [mm/rev], the theoretical air cut amount is 8.0 [μm]. On the other hand, even if the frequency magnification is 0.5 [times] and the amplitude magnification is 1.2 [times], when the feed amount is 0.01 [mm/rev], the theoretical air cut amount is 2.0 [μm]. In this regard, the control device 1 of this embodiment calculates the oscillation amplitude based on the specified air cut amount even if the feed rate changes, so it is possible to avoid a situation in which the results of the chip shredding judgment differ due to a change in the feed rate.

The control device 1 of this embodiment further includes a display unit 16 that outputs information determined by the processing control unit 13. This allows the operator to easily check safety and production plans based on the calculation results of the processing control unit 13, such as the oscillation amplitude.

Next, an embodiment different from the first embodiment will be described. Note that in the following description, configurations common to the above embodiment will be given the same reference numerals and detailed descriptions thereof may be omitted.

[Second embodiment]
6 is a block diagram showing the conditions acquired by the condition acquisition unit 11a of the second embodiment. The control device 1 according to the second embodiment is different from the control device 1 for a machine tool according to the first embodiment in the conditions acquired by the condition acquisition unit 11a and the control method of the machining control unit 13a, but the other configurations are the same as those of the first embodiment.

As shown in FIG. 6, the condition acquisition unit 11a includes a frequency multiplication factor acquisition unit 21, a feed amount acquisition unit 22, and a taper information acquisition unit 23.

The taper information acquisition unit 23 acquires taper information on the taper of the workpiece W from the memory unit 14. The taper information includes information on taper machining, such as the taper angle, which is the movement direction and movement angle of the cutting tool T. The taper angle is, for example, the angle between the central axis and the surface of the workpiece W. The taper information may be specified by the operator and written in the machining program, or may be held as a parameter of the machine tool.

When performing taper machining, the machining control unit 13a of the second embodiment changes the calculation of the oscillation amplitude by taking into account the magnitude of the taper angle. More specifically, the oscillation amplitude is calculated based on Fz, which is the speed component in the Z-axis direction of the feed amount F. The effect of the taper angle differs depending on the degree of the angle. Below, the calculation of Fz, which is the speed component in the Z-axis direction of the feed amount F, is explained separately for the cases when the taper angle is small and large.

FIG. 7 is a diagram showing a schematic diagram of the positional relationship between the workpiece and the cutting tool when the taper angle θ1 is small. In the example shown in FIG. 7, since the taper angle θ1 is small, even if geometric calculations are used to calculate Fz, which is the speed component in the Z-axis direction of the feed amount F, Fz will be approximately equal to F because F ≒ Fz holds. For example, even if F = feed amount 0.1 [mm/rev], Fz = 0.1 [mm/rev] can be used. In this case, Fz = 0.1 is substituted into formula (1) as F to calculate the oscillation amplitude A.

Figure 8 is a schematic diagram showing the positional relationship between the workpiece and the cutting tool when the taper angle is small. In the example shown in Figure 7, because the taper angle θ2 is large, it cannot be said that F ≒ Fz holds even if Fz is calculated using geometric calculations. For example, when F = feed rate 0.1 [mm/rev], Fz = 0.01 [mm/rev]. In this case, Fz = 0.01 is substituted as F into formula (1) to calculate the oscillation amplitude A.

The control device 1 for a machine tool that performs machining while oscillating the cutting tool T and the workpiece W relative to one another according to the second embodiment described above provides the following effects.

The condition acquisition unit 11a of the second embodiment acquires taper information related to the movement direction and movement angle of the cutting tool T, and the machining control unit 13a acquires the feed amount in the oscillation direction (feed amount Fz) based on the taper information and information related to the feed amount, and uses the feed amount in the oscillation direction to determine information (oscillation amplitude A) that the condition acquisition unit 11 has not acquired. In the conventional technology, in either case of FIG. 6 or FIG. 7, the specified air cut amount is not specified, so even if the feed rate is constant, the feed rate in the Z-axis direction changes, and the chip shredding judgment result changes. In this regard, in the control device 1 of the second embodiment, even if the taper angle is large and the speed component in the Z-axis direction differs greatly, the oscillation amplitude is calculated based on the specified air cut amount, so that it is possible to avoid a situation in which the chip shredding judgment result differs due to differences in taper angle.

[Third embodiment]
9 is a block diagram showing conditions acquired by a condition acquisition unit 11b of the third embodiment. The control device 1 according to the third embodiment is different from the control device 1 for a machine tool according to the first embodiment in the conditions acquired by the condition acquisition unit 11b and the control method of the machining control unit 13b, but the other configurations are the same as those of the first embodiment.

As shown in FIG. 9, the condition acquisition unit 11b includes a feed amount acquisition unit 22 and a specific information acquisition unit 24.

The specific information acquisition unit 24 acquires specific information from the storage unit 14 for the machining control unit 13b to identify information on the relative number of oscillations per rotation between the cutting tool T and the workpiece W (oscillation frequency magnification I) and the oscillation amplitude for the relative feed amount per rotation between the cutting tool T and the workpiece (oscillation amplitude magnification K). If it is possible to uniquely determine either the oscillation frequency magnification I or the oscillation amplitude magnification K, it becomes possible to calculate the other using formula (1).

An example of the specific information acquired by the specific information acquisition unit 24 will be described. The specific information may be a specified chip length indicating the chip length specified by the operator. By setting the specified chip length, the oscillation frequency multiplier I can be uniquely determined. The specific information can also be an upper limit value of the frequency. For example, it is possible to configure the oscillation frequency to be set close to the frequency upper limit value, and the oscillation number per one rotation of the spindle is fixed at 0.5 if the frequency upper limit value is not exceeded, and to reduce the oscillation number per one rotation of the spindle until it becomes equal to or less than the upper limit value if the upper limit value is exceeded. In this way, the oscillation frequency multiplier I can be specified. The specific information can also be a recommended value of the oscillation frequency, and the oscillation frequency multiplier I can be uniquely determined even if the setting is such that operation is performed at the recommended value.

Furthermore, if the specific information is set as the upper limit value of the oscillation amplitude and the oscillation amplitude is always set to the upper limit value, the oscillation amplitude magnification K can be uniquely specified. Furthermore, after specifying the oscillation amplitude magnification K as the specific information, if there are multiple options for the oscillation frequency magnification I, the oscillation frequency magnification I for performing processing control can be uniquely specified by selecting the oscillation frequency magnification I with the smaller value. Furthermore, the specific information is set as the lower limit value of the oscillation amplitude, and if the oscillation frequency magnification I is 1.0 or I is 0.99 and is caught by the amplitude upper limit value, the oscillation frequency magnification I can be uniquely specified by shifting the oscillation frequency magnification I in the smaller direction. Furthermore, the specified speed upper limit value, acceleration upper limit value, jerk upper limit value, etc. may be used as the specific information. Alternatively, the acceleration may be controlled to be the minimum. Furthermore, a plurality of these exemplified specific information may be combined. In this way, the specific information is a rule set in the machine tool, and may be information that the processing control unit 13 can specify.

In the above example, out of the three pieces of information, feed amount, oscillation frequency magnification I, and oscillation amplitude magnification K, information on the feed amount is obtained, and the oscillation frequency magnification I and oscillation amplitude magnification K are determined based on the specified air cut amount and specific information. However, a configuration in which information on the oscillation frequency magnification I or oscillation amplitude magnification K is obtained instead of the feed amount, and the remaining two are determined based on the specified air cut amount and specific information is also possible.

In that case, the specific information can uniquely identify the feed rate using an index related to the cycle time and an index related to the surface roughness.

The machining control unit 13b in the third embodiment determines the oscillation frequency magnification I and the oscillation amplitude magnification K based on the feed amount, the specified air cut amount, and the specific information.

The control device 1 for a machine tool that performs machining while oscillating the cutting tool T and the workpiece W relative to one another according to the third embodiment described above provides the following effects.

The condition acquisition unit 11b in the third embodiment acquires, of the three pieces of information, information on the feed amount as a prerequisite, and acquires specific information indicating a condition for identifying information on the oscillation number or information on the oscillation amplitude, and the machining control unit 13b determines information on the oscillation number and information on the oscillation amplitude based on the information on the feed amount and the specific information so that the air cut amount based on the gap between the pass of n rotations and the pass of a rotation later than n rotations becomes the specified air cut amount. As a result, in a configuration in which the condition acquisition unit 11b acquires the feed amount, the oscillation frequency magnification I and the oscillation amplitude magnification K can be easily identified by utilizing the specific information.

In addition, the configuration of the control device 1 in the above embodiment can be modified as appropriate depending on the circumstances, such as omitting some functions or adding other functions.

In the above embodiment, the

machining control units

13, 13a, and 13b all calculate the oscillation amplitude, but they may be configured to determine the amplitude magnification instead of the oscillation amplitude. In this case, in the control stage, the amplitude is determined from the feed amount per spindle revolution and the amplitude magnification, and control is performed using that amplitude.

The machining control unit may be configured to determine information different from the information on the oscillation amplitude depending on the conditions acquired by the condition acquisition unit. For example, the condition acquisition unit may acquire information on the oscillation number and information on the oscillation amplitude, and the machining control unit may determine information on the feed amount based on the information on the oscillation number and the information on the oscillation amplitude. The condition acquisition unit may acquire information on the oscillation number, information on the feed amount set in the machine tool, and specific information that identifies the information on the oscillation amplitude, and the machining control unit may determine information on the feed amount and information on the oscillation amplitude based on the information on the oscillation number and the specific information. The condition acquisition unit may acquire information on the oscillation amplitude, and specific information that identifies the information on the feed amount set in the machine tool and the information on the oscillation number, and the machining control unit may determine information on the feed amount and information on the oscillation number based on the information on the oscillation amplitude and the specific information. Specific numerical values can be calculated using formula (1).

The above-mentioned determination method and calculation method are merely examples, and the information required for processing control may be calculated using a method other than the method using the above-mentioned formula.

Note that this disclosure is not limited to the above-described embodiments, and any modifications or improvements that achieve the objectives of this disclosure are included in this disclosure.

In the above embodiment, the present disclosure is applied to a control device for a machine tool, but is not limited to this. The present disclosure may also be applied to a display device for a machine tool.

Here, FIG. 10 is a functional block diagram of the display device 9 of the machine tool according to the modified example. As shown in FIG. 10, the display device 9 of the machine tool includes a condition input unit 91, an air cut amount input unit 92, an information calculation unit 93, and a display unit 96.

The condition input unit 91 corresponds to the

condition acquisition units

11, 11a, and 11b in the above embodiment. That is, the condition input unit 91 accepts input of one or two pieces of information as prerequisites out of three pieces of information: information on the relative feed amount per revolution between the cutting tool and the workpiece, information on the relative number of oscillations per revolution between the cutting tool and the workpiece, and information on the oscillation amplitude for the relative feed amount per revolution between the cutting tool and the workpiece.

The air cut amount input unit 92 corresponds to the air cut amount acquisition unit 12 in the above embodiment. That is, the air cut amount input unit 92 accepts input of a specified air cut amount that indicates the degree of air cut in the swing direction.

The information calculation unit 93 corresponds to a part of the

machining control units

13, 13a, and 13b in the above embodiment. That is, the information calculation unit 93 calculates, based on preconditions, the information among the three pieces of information that is not accepted by the condition input unit, so that the air cut amount based on the gap between the pass of n rotations and the pass of a rotation after n rotations becomes the specified air cut amount.

The display unit 96 corresponds to the display unit 16 in the above embodiment. That is, the display unit 96 displays the information calculated by the information calculation unit 93.

The machine tool display device 9 having the above configuration provides the same effects as the machine tool control device 1 according to the above embodiment.

REFERENCE SIGNS LIST 1 Machine

tool control device

11, 11a, 11b Condition acquisition unit 12 Air cut

amount acquisition unit

13, 13a, 13b Machining control unit 16 Display unit 9 Machine tool display device 91 Condition input unit 92 Air cut amount input unit 93 Information calculation unit 96 Display unit

Claims

A control device for a machine tool that performs machining while relatively swinging a cutting tool and a workpiece,
a condition acquisition unit that acquires, as a precondition, one or two of the following three pieces of information: information on a relative feed amount per rotation between the cutting tool and the workpiece; information on a relative number of oscillations per rotation between the cutting tool and the workpiece; and information on an oscillation amplitude with respect to the relative feed amount per rotation between the cutting tool and the workpiece;
an air cut amount acquisition unit that acquires a designated air cut amount indicating the degree of air cut in the swing direction;
a machining control unit that determines, based on the preconditions, one of three pieces of information that has not been acquired by the condition acquisition unit, and performs machining control so that an air cut amount based on the gap between a path of n rotations and a path of a rotation later than n rotations becomes the specified air cut amount.
the condition acquisition unit acquires, as the precondition, information relating to the feed amount and information relating to the oscillation number among the three pieces of information;
2. The control device for a machine tool according to claim 1, wherein the machining control unit determines information regarding the oscillation amplitude based on information regarding the feed amount and information regarding the oscillation number so that an air cut amount based on an air cut amount between a pass of n rotations and a pass of a rotation later than n rotations becomes the specified air cut amount.
the condition acquisition unit acquires one of the three pieces of information as the prerequisite, and acquires specific information indicating a condition for identifying information on the remaining two pieces of information;
2. The control device for a machine tool according to claim 1, wherein the machining control unit determines the remaining two pieces of information based on any one of the pieces of information and the specific information so that an air cut amount based on an air cut amount between a pass of n rotations and a pass of a rotation later than n rotations becomes the specified air cut amount.
the condition acquisition unit acquires taper information relating to a moving direction and a moving angle of the cutting tool;
The control device for a machine tool according to claim 1 , wherein the machining control unit determines the feed amount by using the taper information.
A display device for a machine tool that performs machining while oscillating a cutting tool and a workpiece relative to each other,
a condition input unit that accepts input of one or two pieces of information as prerequisites out of three pieces of information: information on a relative feed amount per rotation between the cutting tool and the workpiece, information on a relative number of oscillations per rotation between the cutting tool and the workpiece, and information on an oscillation amplitude with respect to the relative feed amount per rotation between the cutting tool and the workpiece;
an air cut amount input unit that receives an input of a designated air cut amount indicating the degree of air cut in the swing direction;
an information calculation unit that calculates, based on the preconditions, information that is not accepted by the condition input unit among the three pieces of information, so that an air cut amount based on a gap between a path of n rotations and a path of a rotation subsequent to the n rotations becomes the designated air cut amount;
and a display unit that displays the information calculated by the information calculation unit.