Control device for a machine tool and display device for a machine tool

Abstract

A technology is provided that enables an accurate assessment of whether chip comminution is possible during oscillating cutting, even when machining conditions change, and also facilitates the adjustment of machining conditions.A control device 1 for a machine tool comprises: a condition detection unit 11, which detects as preconditions one or two pieces of information from three pieces of information, namely a feed rate F, an oscillation frequency multiplier I and an oscillation amplitude multiplier K; an air cut detection unit 12, which detects a defined air cut, indicating the degree of air cut in an oscillation direction; and a machining control unit 13, which, based on the preconditions, determines the piece(s) of information from the three pieces of information not detected by the condition detection unit 11, such that an air cut based on a quantity between n rotations and the rotation following the nth rotation corresponds to a defined air cut, and which performs machining control.

Description

Technical field

[0001] The present disclosure relates to a control device for a machine tool and a display device for a machine tool. State of the art

[0002] Chips are continuously generated during machining. It is known to perform machining while a cutting tool and workpiece are relatively oscillating to avoid a situation where chip entanglement with the workpiece and cutting tool, or similar chip behavior, leads to machining errors, machine failures, and the like.

[0003] In this type of oscillating machining, a setting is made so that a tool path, i.e., a trajectory of the tool, partially overlaps with the previous tool path. This causes the tool to move idly while separated from the workpiece surface, which is called air cutting, and the chips are crushed (see, for example, Patent Documents 1 and 2). Citation listPatent document Patent Document 1: Unexamined Japanese Patent Application, Publication No. 2018-094690 Patent Document 2: Unexamined Japanese Patent Application, Publication No. 2020-009248 Disclosure of the invention Problems to be solved by the invention

[0004] Cutting operation settings are often determined based on an amplitude multiplication factor, which is a ratio of an amplitude to a tool feed rate per rotation of a spindle. To ensure that the tool performs the air cutting operation, the amplitude multiplication factor is set to a value with a small margin, rather than the limit of a range in which the tool performs the air cutting. For example, even in a case where the cutting tool theoretically performs air cutting with an amplitude multiplication factor of 1.0, machining was usually performed with an amplitude multiplication factor of 1.2, which has a margin.

[0005] However, when using the amplitude multiplication factor method to determine the oscillation amplitude, a difference in feed rate will either enable or disable chip crushing even with the same amplitude multiplication factor. In taper machining, in a case where the feed rate is constant but the taper angle is large, chip crushing is either possible or impossible because the feed rate in one oscillation direction is low. Therefore, it is difficult to adjust the machining conditions.

[0006] First, since a value of the amplitude multiplication factor necessary for enabling chip reduction depends on a value set as a frequency multiplication factor and indicates the number of oscillations per rotation of the spindle, the method for setting the amplitude multiplication factor itself is difficult to understand when it comes to whether chip reduction is possible or not, which complicates the adjustment of machining conditions.

[0007] The present disclosure has been achieved in view of the above-described disadvantages, and an object of the present disclosure is to provide an oscillatory cutting method that enables accurate determination of whether chip reduction is possible or not and facilitates adjustment of a machining condition. Means for solving the problems

[0008] The present disclosure relates to a control device for a machine tool that performs machining while a cutting tool and a workpiece oscillate relative to each other, the control device comprising: a condition detection unit configured to detect, as a precondition, one or two pieces of information from among three pieces of information including information regarding a feed amount per relative rotation of the cutting tool and the workpiece, information regarding a number of oscillations per relative rotation of the cutting tool and the workpiece, and information regarding an oscillation amplitude related to the feed amount per relative rotation of the cutting tool and the workpiece; an air cutting amount detection unit configured to detect a predetermined air cutting amount indicating a degree of air cutting in an oscillation direction;and a machining control unit configured to determine, based on the precondition, the information among the three pieces of information not detected by the condition detecting unit so that an air intersection amount based on an interval between a pass in an n-th rotation and a pass in a rotation after the n-th rotation corresponds to the set air intersection amount, the machining control unit being configured to perform machining control;

[0009] Furthermore, the present disclosure is directed to a display device for a machine tool that performs machining while a cutting tool and a workpiece oscillate relative to each other, the display device comprising: a condition input unit configured to receive, as a precondition, an input of one or two items of information from among three items of information including information regarding a feed amount per relative rotation of the cutting tool and the workpiece, information regarding a number of oscillations per relative rotation of the cutting tool and the workpiece, and information regarding an oscillation amplitude related to the feed amount per relative rotation of the cutting tool and the workpiece;an air intersection amount input unit configured to receive an input of a set air intersection amount indicating a degree of air cutting in an oscillation direction; an information calculation unit configured to calculate, based on the precondition, the information among the three pieces of information not received from the condition input unit so that an air intersection amount based on an interval between a pass in an n-th rotation and a pass in a rotation after the rotation following the n-th rotation corresponds to the set air intersection amount; and a display unit configured to display the information calculated by the information calculation unit. Effects of the invention

[0010] The present disclosure can provide a technique for oscillating cutting that makes it possible to accurately determine whether chip crushing is possible or not and facilitates adjustment of machining conditions. Short description of the drawings Fig. 1 is a diagram explaining oscillating cutting; Fig. 2 is a functional block diagram of a control device for a machine tool according to a first embodiment; Fig. 3 is a block diagram showing the conditions detected by a condition detecting unit according to the first embodiment; Fig. 4 shows an example of a machining program; Fig. 5 is a diagram schematically illustrating a positional relationship between a workpiece and a cutting tool; Fig. 6 is a block diagram illustrating the conditions detected by a condition detection unit according to a second embodiment; Fig. 7 is a diagram schematically illustrating a positional relationship between a workpiece and a cutting tool when a taper angle is small; Fig. 8 is a diagram schematically illustrating a positional relationship between a workpiece and a cutting tool when a taper angle is large; Fig. 9 is a block diagram showing the conditions detected by a condition detection unit according to a third embodiment; and Fig. 10 is a functional block diagram of a display device for a machine tool according to a modification. Preferred manner of carrying out the invention

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. [First embodiment]

[0012] A control device 1 for a machine tool according to a first embodiment of the present invention is suitable for performing oscillating cutting (turning) in which a cutting tool cuts a workpiece while the cutting tool and the workpiece oscillate relative to each other. First, the oscillating cutting will be described with reference to Fig. 1 described.

[0013] Fig. 1 is a diagram explaining oscillating cutting. In the Fig. In the 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 shaft that moves the cutting tool T relative to the workpiece W are operated so that cutting is performed while the cutting tool T and the workpiece W oscillate relative to each other in a feed direction simultaneously with the relative rotation of the cutting tool T and the workpiece W. At this time, the tool path, that is, the trajectory of the cutting tool T, is set so that the current path partially overlaps with the previous path. Since a portion machined in the previous path is partially included in the current path, the cutting edge of the cutting tool T is caused to idly move while being separated from the surface of the workpiece W, which is called air cutting, thereby crushing chips.

[0014] It should be noted that the workpiece for oscillating cutting in the present embodiment is not limited to a specific shape. Specifically, the oscillating cutting according to the present embodiment is applicable to a case where multiple feed axes (a Z axis and an X axis) are required to machine a workpiece having a tapered portion or an arcuate portion on a surface to be machined, and a case where a specific single feed axis (a Z axis) is sufficient to machine a workpiece having a circular columnar shape or a cylindrical shape.

[0015] A configuration of the control device 1 for a machine tool is described below. Fig. 2 is a functional block diagram of the machine tool control device 1 according to the present embodiment. The machine tool control device 1 is composed of, for example, a computer including memories such as a read-only memory (ROM) and a random access memory (RAM), a central processing unit (CPU), and a communication control unit connected to each other via a bus. The functions and operations of the functional units are realized through the cooperation between the CPU and the memories built into the computer and the control programs stored in the memories. The machine tool control device 1 can be constituted by a computer numerical control (CNC), a programmable logic controller (PLC), or the like.Alternatively, the machine tool control device 1 may be connected to a host computer that outputs machining conditions such as a rotational speed and the like in addition to a machining program. For simplicity, . Fig. 2 only one motor 3 is shown, which drives a feed shaft.

[0016] As in Fig. 2, the control device 1 for a machine tool includes a condition detection unit 11, an air intersection amount detection unit 12, a machining control unit 13, a storage unit 14, an input unit 15, and a display unit 16.

[0017] The condition acquisition unit 11 acquires a machining condition and an oscillation condition for performing oscillating machining of the workpiece W. The machining condition and the oscillation condition may be stored in the storage unit 14 or output from an external computer.

[0018] Here, the machining condition includes at least information about a feed amount per relative rotation of the cutting tool and the workpiece and information about a shape of a cutting edge of the cutting tool. In addition, the machining condition includes, for example, information about a rotational speed S (rpm) of a spindle, a feed rate (mm / min) for the cutting tool, a workpiece radius (mm), a clearance angle (°) of the cutting tool, and the like. Examples of information regarding a feed amount per relative rotation of the cutting tool and the workpiece include a feed amount F per rotation (mm / rev), a combination of a rotational speed S (rpm) of the spindle and a feed rate (mm / min) of the cutting tool, and the like. An example of information about the shape of the cutting edge of the cutting tool is the cutting edge R (mm).

[0019] The oscillation condition includes information about the number of oscillations per relative rotation of the cutting tool and the workpiece, as well as information regarding an oscillation amplitude related to the feed rate per relative rotation of the cutting tool and the workpiece. An example of the information regarding the number of oscillations per relative rotation of the cutting tool and the workpiece is an oscillation frequency multiplication factor I (times), which indicates an oscillation frequency per rotation of the spindle. An example of the information about the oscillation amplitude related to the feed rate per relative rotation of the cutting tool and the workpiece is an oscillation amplitude multiplication factor K (times), which indicates the magnitude of an oscillation amplitude related to the magnitude of a feed rate per rotation of the spindle.The oscillation frequency multiplication factor I (times) can be specified directly or calculated from a previously specified oscillation frequency (Hz) and a spindle speed S (rpm). Similarly, the oscillation amplitude multiplication factor K (times) can be specified directly or calculated from a previously specified oscillation amplitude (mm), a feed rate (mm / min), and a spindle speed S (rpm).

[0020] The air intersection detection unit 12 detects a predetermined air intersection set in advance by an operator or the like. The air intersection may, for example, be stored in the storage unit 14, retrieved from an external computer, or input via the input unit 15.

[0021] The air intersection amount used here refers to an air intersection amount in the interval between a pass in an nth rotation and a pass in a rotation after the nth rotation (the (n+1)th or subsequent rotation). In the present embodiment, the air intersection amount in the interval between the pass in the nth rotation and the pass in the (n+1)th rotation is used to determine the machining condition, but the present invention is not limited to this. For example, an air intersection amount in the interval between the pass in the nth rotation and the pass in the (n+2)th rotation can be used to determine the machining condition.

[0022] In the present embodiment, a distance in an oscillation direction is used as the air cutting amount. In the present embodiment, oscillation occurs in the feed direction of the feed shaft, and accordingly, the air cutting amount is a numerical value indicating the degree of air cutting in the feed direction. It is convenient for the air cutting amount to be an indicator of the extent of air cutting, and the air cutting amount may be a distance in the oscillation direction. Alternatively, the air cutting amount may be expressed by an area including the oscillation direction, a plane or dimension associated with an air cutting amount set in advance in a table, or a multiplication factor with respect to any reference value (e.g., a workpiece radius, a feed amount, etc.).

[0023] The machining control unit 13 performs machining control based on the condition detected by the condition detection unit 11 so that the air cutting amount after machining starts corresponds to the set air cutting amount. The details of the machining control by the machining control unit 13 will be described later.

[0024] The storage unit 14 stores various types of information for controlling the machine tool and performing machining. In the present embodiment, the storage unit 14 stores the machining condition, the oscillation condition, and the air cutting amount set by the operator. The machining condition, the oscillation condition, and the air cutting amount are, for example, input by the operator into a machining program or set as parameters of the machine tool. The storage unit 14 may be arranged outside the control device 1 instead of being arranged in the control device 1.

[0025] The input unit 15 inputs machining information when the operator inputs it through an input device (not shown), such as a keyboard or a touch panel. The machining information input by the input unit 15 is stored in the storage unit 14 and the like, or input to each unit of the control device 1.

[0026] The display unit 16 displays various types of information regarding the machine tool, the control device 1 and the machining.

[0027] Hereinafter, the conditions detected by the condition detection unit 11 and the machining control performed by the machining control unit 13 will be described with reference to Fig. 3 described. Fig. 3 is a block diagram showing the conditions detected by the condition detection unit 11 according to the first embodiment.

[0028] As in Fig. 3, the condition detection unit 11 includes a frequency multiplication factor detection unit 21 and a feed rate detection unit 22. The frequency multiplication factor detection unit 21 is an oscillation number detection unit for detecting information regarding the number of oscillations per relative rotation of the cutting tool and the workpiece, and detects the oscillation frequency multiplication factor I (times) as information regarding the number of oscillations. The feed rate detection unit 22 detects the feed rate F (mm / rev) per spindle rotation as information regarding the feed rate per relative rotation of the cutting tool and the workpiece.

[0029] Fig. 4 shows an example of a machining program. Fig. 4 contains various types of information that are specified by the operator via the input unit 15 or the like. In the Fig. In the machining program shown in Figure 4, the "S2000 M03" block is a description indicating that the spindle should be rotated forward. The "G8.5 P2 I0.5 L0.02" block contains "I0.5," which indicates a frequency multiplication factor, and "L0.02," which indicates a specified air cutting amount. In the "G01 Z20.0 F0.1" block, "F0.1" is a description indicating a feed rate.

[0030] When a machining operation is started, the condition detection unit 11 of the control device 1 detects a frequency multiplication factor and a feed rate from the machining program, and the air intersection detection unit 12 detects a specified air intersection. Fig. In the example shown in FIG. 4, the condition detection unit 11 detects a frequency multiplication factor of 0.5 [times] from "I0.5" and detects a feed amount per revolution of 0.1 [mm / U] from "F0.1". The air gap amount detection unit 12 detects a specified air gap amount of 0.02 [mm] from "L0.02".

[0031] Based on the frequency multiplication factor and the feed amount detected by the condition detection unit 11, and the specified air gap amount detected by the air gap amount detection unit 12, the processing control unit 13 determines an oscillation amplitude for performing oscillatory cutting according to the following equation. In this example, a frequency multiplication factor of 0.5 [times], a feed amount per revolution of 0.1 [mm / U], and a specified air gap amount of 0.02 [mm] are substituted into the equation. (F(θ−2π2π)+(A⋅(cos(I(θ−2π))−1)))−(F(θ2π)+(A⋅(cos(Iθ)−1)))=L[mm]

[0032] In equation (1), I stands for the frequency multiplication factor [times], F stands for the feed rate per rotation [mm / rev], L stands for the specified air intersection amount [mm], A stands for the oscillation amplitude [mm] and θ stands for a workpiece phase [°] in which the air intersection amount L is reached.

[0033] Fig. 5 is a diagram schematically illustrating a positional relationship between the workpiece W and the cutting tool T. As in Fig. 5, the machining control unit 13 performs the oscillating cutting based on the oscillation amplitude A calculated according to equation (1) so that the air cutting amount in the interval between the previous pass, which is the n-th cutting pass, and the current pass, which is the (n+1)-th cutting pass, corresponds to the set air cutting amount.

[0034] The machining control unit 13 outputs information about the calculated oscillation amplitude to the display unit 16. The display unit 16 transmits the oscillation amplitude to the operator by means of character information indicating the oscillation amplitude, by graphic information specifying the oscillation amplitude, by a combination thereof, or the like.

[0035] According to the first embodiment described above, the control device 1 for a machine tool that performs machining while a cutting tool T and a workpiece W oscillate relative to each other has the following effects.

[0036] The control device 1 for a machine tool according to the present embodiment includes: a condition acquisition unit 11 that acquires, as a precondition, one or two pieces of information from among three pieces of information including information regarding a feed amount per relative rotation of the cutting tool T and the workpiece W (e.g., a feed amount F), information regarding the number of oscillations per relative rotation of the cutting tool T and the workpiece W (e.g., an oscillation frequency multiplication factor I), and information regarding an oscillation amplitude related to the feed amount per relative rotation of the cutting tool T and the workpiece W (e.g.,, an oscillation amplitude multiplication factor K); an air cutting amount detection unit 12 that detects a set air cutting amount indicating a degree of air cutting in an oscillation direction; and a machining control unit 13 that determines, based on the precondition, the information not detected by the condition detection unit 11 such that an air cutting amount based on an interval between a pass in an n-th rotation and a pass in a rotation after the n-th rotation is equal to the set air cutting amount, wherein the machining control unit 13 is configured to perform machining control.Due to this feature, since the specified air cutting amount is set as a target value, it is possible to accurately determine whether chip crushing is possible or not even if the machining condition is changed during oscillating cutting, and the setting of the machining condition can be facilitated.

[0037] The condition detection unit 11 of the present embodiment detects, as a precondition, the information regarding the feed amount and the information regarding the number of oscillations from the three pieces of information, and the machining control unit 13 determines the information regarding the oscillation amplitude based on the information regarding the feed amount and the information regarding the number of oscillations, so that the air cutting amount corresponds to the specified air cutting amount based on the interval between the pass in the n-th rotation and the pass in the rotation after the n-th rotation ((n+1)-th rotation). When adopting the method of determining an oscillation amplitude by setting an oscillation amplitude multiplication factor as in the prior art, a difference in the feed rate enables or prohibits chip cutting even if the amplitude multiplication factor is the same.For example, when the frequency multiplication factor is 0.5 [times], the amplitude multiplication factor is 1.2 [times], and the feed rate is 0.04 [mm / rev], the theoretical air cutting amount is 8.0 [µm]. On the other hand, although the frequency multiplication factor is 0.5 [times] and the amplitude multiplication factor is 1.2 [times], the theoretical air cutting amount is 2.0 [µm] when the feed rate is 0.01 [mm / rev]. In this regard, the control device 1 of the present embodiment calculates the oscillation amplitude based on the set air cutting amount even when the feed rate changes, thereby making it possible to avoid a situation where the chip cutting determination result varies due to a change in the feed rate.

[0038] The control device 1 of the present embodiment further includes a display unit 16 that outputs the information acquired by the machining control unit 13. This function allows an operator to easily check safety and a manufacturing plan based on the calculation result of the control unit 13, such as the oscillation amplitude.

[0039] Next, embodiments different from the first embodiment will be described. In the following description, the same components as those in the above-described embodiment are denoted by the same reference numerals, and a detailed description thereof may be omitted as appropriate. [Second embodiment]

[0040] Fig. FIG. 6 is a block diagram showing the conditions detected by a condition detection unit 11a of a second embodiment. The control device 1 according to the second embodiment is the same as the control device 1 for a machine tool according to the first embodiment, except for the conditions detected by the condition detection unit 11a and the control procedure executed by a machining control unit 13a.

[0041] As shown in Fig. FIG. 6, the condition detection unit 11a includes a frequency multiplication factor detection unit 21, a feed amount detection unit 22, and a taper information detection unit 23.

[0042] The taper information acquisition unit 23 acquires taper information regarding a taper of a workpiece W from a storage unit 14. The taper information includes, for example, information about taper machining, such as a moving direction of a cutting tool T and a taper angle, which is a moving angle of the cutting tool T. The taper angle is, for example, an angle formed by a central axis and a surface of the workpiece W. The taper information may be described in a machining program according to designation by an operator or stored as parameters of the machine tool.

[0043] When performing taper machining, the machining control unit 13a of the second embodiment changes the calculation of a vibration amplitude in consideration of the size of the taper angle. More specifically, the machining control unit 13a calculates the vibration amplitude based on Fz, a speed component of a feed amount F in the Z-axis direction. The influence of the taper angle depends on how large or small the angle is. The following describes the calculation of Fz, the speed component of the feed amount F in the Z-axis direction, both for the case where the taper angle is small and for the case where the taper angle is large.

[0044] Fig. 7 is a diagram schematically showing a positional relationship between the workpiece and the cutting tool when the taper angle θ1 is small. In the Fig. In the example shown in Figure 7, since the cone angle θ1 is small, even if Fz, the speed component of the feed amount F in the Z-axis direction, is calculated by geometric calculation, the speed component Fz of the feed amount F in the Z-axis direction is substantially the same as the feed amount F because F ≈ Fz is satisfied. For example, even if F = a feed amount of 0.1 [mm / rev], Fz can be set to 0.1 [mm / rev]. In this case, Fz = 0.1 is substituted as F in Equation (1) to calculate the oscillation amplitude A.

[0045] Fig. Figure 8 is a diagram schematically showing a positional relationship between the workpiece and the cutting tool when the taper angle is small. Fig. In the example shown in Figure 8, the cone angle θ2 is large, so F ≈ Fz cannot be satisfied even if Fz is calculated using geometric calculation. For example, if F = a feed rate of 0.1 [mm / rev], Fz is 0.01 [mm / rev]. In this case, Fz = 0.01 is substituted as F in Equation (1) to calculate the oscillation amplitude A.

[0046] According to the second embodiment described above, the control device 1 for a machine tool that performs machining while a cutting tool T and a workpiece W oscillate relative to each other exerts the following effects.

[0047] According to the second embodiment, a condition detection unit 11a detects taper information regarding a moving direction and a moving angle of the cutting tool T, and a machining control unit 13a detects a feed amount (feed amount F) in an oscillation direction based on the taper information and the information regarding the feed amount, and determines information not detected by the condition detection unit 11a (an oscillation amplitude A) using the feed amount in the oscillation direction. According to the prior art, in the two Fig. 6 and Fig. In the cases shown in Figure 7, no air cutting amount is set, and therefore, even if the feed rate is set to be constant, the feed rate in the Z-axis direction changes, and the chip crushing determination result varies. In this regard, the control device 1 of the second embodiment calculates the oscillation amplitude based on a set air cutting amount, and therefore, it is possible to avoid a situation in which the chip crushing determination result varies due to a difference in the cone angle, even if a cone angle is large and the speed component in the Z-axis direction is significantly different. [Third Embodiment]

[0048] Fig. 9 is a block diagram illustrating the conditions detected by a condition detection unit 11b of a third embodiment. The control device 1 according to the third embodiment is the same as the control device 1 for a machine tool according to the first embodiment, except for the conditions detected by the condition detection unit 11b and the control method executed by a machining control unit 13b.

[0049] As in Fig. 9, the condition detection unit 11b includes a feed amount detection unit 22 and an identification information detection unit 24.

[0050] The identification information acquisition unit 24 acquires, from a storage unit 14, identification information for the machining control unit 13b to identify information regarding the number of oscillations per relative rotation of a cutting tool T and a workpiece W (oscillation frequency multiplication factor I) and an oscillation amplitude with respect to a feed amount per relative rotation of the cutting tool T and the workpiece (oscillation amplitude multiplication factor K). When one of the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K is uniquely determined, the other can be calculated according to Equation (1).

[0051] The following describes examples of the identification information acquired by the acquisition unit 24. The identification information may be a set chip length indicating a chip length set by an operator. By setting the set chip length, the oscillation frequency multiplication factor I can be uniquely determined. Alternatively, the identification information may also be an upper frequency limit value. For example, a configuration may be adopted in which the oscillation frequency is set to always be close to the upper frequency limit value, the number of oscillations per spindle rotation is set to 0.5 as long as the upper frequency limit value is not exceeded, and in a case where the oscillation frequency exceeds the upper frequency limit value, the number of oscillations per spindle rotation is reduced until the oscillation frequency drops to the upper frequency limit value or less.With this configuration, the oscillation frequency multiplication factor I can be determined. Alternatively, the identification information may be a recommended value for the oscillation frequency, and a setting may be made so that the operation is performed with the recommended value, thereby uniquely identifying the oscillation frequency multiplication factor I.

[0052] Alternatively, the identification information may be an upper limit of the oscillation amplitude, and the oscillation amplitude may always be set to the upper limit, thereby uniquely identifying the oscillation amplitude multiplication factor K. Alternatively, in a case where the oscillation amplitude multiplication factor K is set as the identification information and there are a plurality of options of the oscillation frequency multiplication factor I, setting may be made so that an oscillation frequency multiplication factor I with a small value is selected, thereby uniquely identifying the oscillation frequency multiplication factor I for performing machining control.Alternatively, the identification information may be a lower limit value of the oscillation amplitude, and setting may be made such that when the upper amplitude limit is reached while the oscillation frequency multiplication factor I is 1.0 or 0.99, the oscillation frequency multiplication factor I is shifted to decrease it, whereby the oscillation frequency multiplication factor I can be uniquely identified. Alternatively, a set upper speed limit, a set upper acceleration limit, a set upper jerk limit, or the like may be set as the identification information. Alternatively, control may be performed so that the acceleration becomes the lowest. Furthermore, two or more of the above-described examples of the identification information may be combined.As described above, the identification information is a set of rules for the machine tool and may be any information as long as it enables the machining control unit 13 to identify the information.

[0053] In the example described above, among the three pieces of information, namely the feed rate, the oscillation frequency multiplication factor I, and the oscillation amplitude multiplication factor K, the information related to the feed rate is acquired, and the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K are determined based on the set air intersection amount and the identification information. However, instead of the feed rate, the oscillation frequency multiplication factor I or the oscillation amplitude multiplication factor K may also be obtained, and the remaining two pieces of information may be determined based on the set air intersection amount and the identification information.

[0054] In this case, the identification information allows a unique identification of the feed rate based on a cycle time indicator or a surface roughness indicator.

[0055] The machining control unit 13b of the third embodiment determines the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K based on the feed amount, the set air cutting amount, and the identification information.

[0056] According to the third embodiment described above, the control device 1 for a machine tool that performs machining while a cutting tool T and a workpiece W oscillate relative to each other exerts the following effects.

[0057] The condition acquisition unit 11b of the third embodiment acquires, as a precondition, information regarding the feed amount from the three pieces of information, and acquires identification information indicating a condition for identifying information regarding the number of oscillations or information regarding an oscillation amplitude. The machining control unit 13b determines the information regarding the number of oscillations and the information regarding the oscillation amplitude based on the information regarding the feed amount and the identification information, so that the air cutting amount corresponds to the specified air cutting amount based on the interval between the pass in the nth rotation and the pass in the rotation after the nth rotation.Due to this feature, in the configuration where the condition detecting unit 11b detects the feed amount, the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K can be easily identified by using the identification information.

[0058] The configuration of the control device 1 of the above-described embodiments can be modified according to the circumstances, for example, by omitting part of the functions or adding another function.

[0059] In the above embodiments, the processing control units 13, 13a, and 13b each calculate the oscillation amplitude, but can be configured to determine an amplitude multiplication factor instead of the oscillation amplitude. In this case, in a control stage, an amplitude is determined from a feed amount per rotation of the spindle and an amplitude multiplication factor, and the control is carried out based on the amplitude.

[0060] The machining control unit may be configured to determine information other than the information regarding the oscillation amplitude depending on the conditions detected by the condition detection unit. For example, the condition detection unit may detect the information regarding the number of oscillations and the information regarding the oscillation amplitude, and the machining control unit may determine the information regarding the feed amount based on the information regarding the number of oscillations and the information regarding the oscillation amplitude.Alternatively, the condition detecting unit may detect the information regarding the number of oscillations and the identification information for identifying the information regarding a feed amount set for the machine tool and the information regarding the oscillation amplitude, and the machining control unit may determine the information regarding the feed amount and the information regarding the oscillation amplitude based on the information regarding the number of oscillations and the identification information.Alternatively, the condition acquisition unit may acquire the oscillation amplitude information and the identification information to identify the information regarding a feed rate set for the machine tool and the information regarding the number of oscillations, and the machining control unit may determine the feed rate information and the information regarding the number of oscillations based on the oscillation amplitude information and the identification information. Specific numerical values ​​can be calculated according to Equation (1).

[0061] The determination method and calculation method described above are examples, and the information required for machining control may be calculated by a method other than the method using the mathematical equation described above.

[0062] It is to be noted that the present disclosure is not limited to the embodiments described above, and modifications and improvements within a range in which the subject matter of the present disclosure can be achieved are encompassed by the present disclosure.

[0063] In the above, the present disclosure is applied to the control device for a machine tool, but the present disclosure is not limited thereto. The present disclosure can also be applied to a display device for a machine tool.

[0064] Fig. 10 is a functional block diagram of a display device 9 for a machine tool according to a modification. As shown in Fig.10, the display device 9 for a machine tool includes a condition input unit 91, an air intersection input unit 92, an information calculation unit 93, and a display unit 96.

[0065] The condition input unit 91 corresponds to the condition acquisition units 11, 11a, and 11b of the above-described embodiments. Specifically, the condition input unit 91 receives, as a precondition, an input of one or two pieces of information from among three pieces of information including information regarding a feed amount per relative rotation of a cutting tool and a workpiece, information regarding the number of oscillations per relative rotation of the cutting tool and the workpiece, and information regarding an oscillation amplitude related to the feed amount per relative rotation of the cutting tool and the workpiece.

[0066] The air intersection input unit 92 corresponds to the air intersection detection unit 12 of the above embodiments. Specifically, the air intersection input unit 92 receives an input of a set air intersection indicating the degree of air cutting in an oscillation direction.

[0067] The information calculation unit 93 corresponds to a part of the machining control units 13, 13a, and 13b of the above embodiments. Specifically, the information calculation unit 93 calculates, based on the precondition, the information among the three pieces of information not received from the condition input unit, so that an air intersection amount based on an interval between a pass in an n-th rotation and a pass in a rotation after the n-th rotation corresponds to the set air intersection amount.

[0068] The display unit 96 corresponds to the display unit 16 of the above-described embodiments. Specifically, the display unit 96 displays the information calculated by the calculation unit 93.

[0069] The display device 9 for a machine tool having the above-described configuration has the same effects as the control device 1 for a machine tool according to the above-described embodiments. Explanation of reference symbols 1 control device for machine tools 11, 11a, 11b Condition detection unit 12 Air flow detection unit 13, 13a, 13b Processing control unit 16 Display unit 9 Display device for machine tools 91 Condition input unit 92 Air intersection input unit 93 Information calculation unit 96 display unit QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2018-094690

[0003] JP 2020-009248

[0003]

Claims

[1] A control device for a machine tool that performs machining while a cutting tool and a workpiece oscillate relative to each other, the control device comprising: a condition detection unit configured to detect, as a precondition, one or two pieces of information from among three pieces of information including information regarding a feed amount per relative rotation of the cutting tool and the workpiece, information regarding a number of oscillations per relative rotation of the cutting tool and the workpiece, and information regarding an oscillation amplitude related to the feed amount per relative rotation of the cutting tool and the workpiece; an air cutting quantity detecting unit configured to detect a predetermined air cutting quantity indicating a degree of air cutting in an oscillation direction; and a machining control unit configured to determine, based on the precondition, the information among the three pieces of information not acquired by the condition acquisition unit so that an air cutting amount based on an interval between a pass in an n-th rotation and a pass in a rotation after the n-th rotation corresponds to the set air cutting amount, wherein the machining control unit is configured to perform machining control. [2] The control device according to claim 1, wherein the condition detection unit detects, as a precondition, the information about the feed amount and the information about the number of oscillations from the three pieces of information, and the machining control unit determines the information regarding the oscillation amplitude based on the information regarding the feed amount and the information regarding the number of oscillations so that the air cutting amount based on the interval between the pass in the n-th rotation and the pass in the rotation after the n-th rotation corresponds to the set air cutting amount. [3] The control device according to claim 1, wherein the condition detection unit detects one of the three pieces of information as the precondition and detects identification information indicating a condition for identifying the remaining two pieces of information of the three pieces of information, and the machining control unit determines the remaining two pieces of information based on the one of the three pieces of information and the identification information so that the air intersection amount corresponds to the set air intersection amount based on the interval between the pass in the n-th rotation and the pass in the rotation after the n-th rotation. [4] The control device according to one of claims 1 to 3, wherein the condition detection unit detects taper information regarding a movement direction and a movement angle of the cutting tool, and the machining control unit determines the feed rate based on the taper information. [5] A display device for a machine tool that performs machining while a cutting tool and a workpiece oscillate relative to each other, the display device comprising: a condition input unit configured to receive, as a precondition, an input of one or two pieces of information from among three pieces of information including information regarding a feed amount per relative rotation of the cutting tool and the workpiece, information regarding a number of oscillations per relative rotation of the cutting tool and the workpiece, and information regarding an oscillation amplitude related to the feed amount per relative rotation of the cutting tool and the workpiece; an air cutting amount input unit configured to receive an input of a set air cutting amount indicating a degree of air cutting in an oscillation direction; an information calculation unit configured to calculate, based on the precondition, the information among the three pieces of information not received from the condition input unit so that an air intersection amount based on an interval between a pass in an n-th rotation and a pass in a rotation after the n-th rotation corresponds to the set air intersection amount; and a display unit configured to display the information calculated by the information calculation unit.

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