Machine tool control device

Abstract

A machine tool control device for controlling thread cutting is provided, the device being capable of automatically setting the thread amount to achieve thread cutting as desired by an operator. A machine tool control device 1 is provided with: a machining condition acquisition unit 11 that acquires machining conditions for thread cutting; a machining determination unit 12 that determines the type of machining from the machining conditions; a thread amount rule setting unit 13 that determines setting rules based on a determination result of the machining determination unit 12, which is a method for setting the thread amount of thread cutting; and a thread amount determination unit 20 that determines the thread amount for machining based on the machining conditions and the setting rules.

Description

Technical area

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

[0002] In order to prevent the chips continuously generated during machining from being caught on a workpiece or a cutting tool and causing abnormal cutting or machine failure, oscillation cutting in which a tool and a workpiece are vibrated relative to each other is usually performed on machine tools (see, for example, Patent Document 1).

[0003] In oscillating cutting of this type, a toolpath, which represents a path of a tool, is set to partially overlap with a previous toolpath to enable a non-contact motion known as air cutting, in which the tool detaches from a surface of a workpiece to thereby break up chips. Citation listPatent document

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-66169 Disclosure of the inventionProblems to be solved by the invention

[0005] In oscillating threading, the operator often specifies a thread amount (a position on the X-axis) that is similar or identical to that used in normal threading, which does not involve oscillation. However, there have been cases where the specified thread amount was not suitable for actual oscillating threading.

[0006] For example, compared to thread cutting without oscillation, oscillation thread cutting results in an increase in the number of machining operations, which, due to the oscillation principle, leads to an increase in cycle time. Although oscillation thread cutting, which allows cooling of the machining heat on the cutting tool during air cutting, has the potential to shorten cycle time by increasing the amount of cutting per operation, such a measure has not been implemented to date. Otherwise, reducing the amount of threading can be advantageous in oscillation thread cutting to reduce the load on the cutting tool, compared to normal thread cutting without oscillation.

[0007] In view of the situations described above, an object of the present disclosure is to provide a technique for automatically setting a thread amount for achieving the thread cutting desired by an operator in a control unit for a machine tool that controls thread cutting. Means to solve the problems

[0008] The present disclosure is a control device for a machine tool that performs thread cutting on a workpiece using a cutting tool, the control device for the machine tool including: a machining condition acquisition unit that acquires machining conditions for thread cutting; a machining determination unit that determines a type of machining from the machining conditions; a thread amount rule setting unit that determines a setting rule, which is a method for setting a thread amount for thread cutting, based on a result of determination by the machining determination unit; and a thread amount determination unit that determines a thread amount used during machining based on the machining conditions and the setting rule. Effects of the invention

[0009] According to the present disclosure, it is possible to provide a technique for automatically setting a thread amount for achieving the thread cutting desired by an operator in a control unit for a machine tool that controls thread cutting. Short description of the figures Fig. 1 is a functional block diagram of a control device for a machine tool according to a first embodiment of the present invention; Fig. 2 is a view showing an example of a machining program in the first embodiment in which oscillation cutting is not performed; Fig. 3 is a diagram showing the position of a workpiece and a cutting tool without oscillation cutting in the first embodiment; Fig. 4 is a view showing an example of a machining program in oscillation cutting in the first embodiment; Fig. 5 is a diagram showing the position of the workpiece and the cutting tool when a first setting rule is applied and the thread amount is changed; Fig. 6 is a diagram showing the position of the workpiece and the cutting tool in oscillation cutting when the first setting rule is applied; Fig. 7 is a diagram illustrating a positional relationship between the workpiece and the cutting tool when a second setting rule is applied and a thread amount is changed; Fig. 8 is a diagram illustrating the position of the workpiece and the cutting tool during oscillation cutting when the second setting rule is applied; Fig. 9 is a flowchart showing an example of generation of a thread cutting command by the machine tool control device; Fig. 10 is a diagram showing the position of the workpiece and the cutting tool when applying a setting rule and setting a thread amount in a second embodiment; Fig. 11 is a functional block diagram of a control device for a machine tool according to a third embodiment; and Fig. 12 is a functional block diagram of a control device for a machine tool according to a fourth embodiment. Preferred mode for carrying out the invention

[0010] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that in the following descriptions, for a second embodiment and later embodiments, like reference numerals denote identical or corresponding configurations to those in a first embodiment, and their descriptions are therefore conveniently omitted. [First embodiment]

[0011] Fig. 1 is a functional block diagram of a control device 1 for a machine tool according to the first embodiment of the present invention. Fig. The control device 1 for the machine tool shown in Figure 1 is a thread cutting device with a cutting tool that oscillates in the diameter direction with respect to a workpiece. Note that in Fig. 1, for the sake of simplicity, only one motor 3 is shown driving one feed shaft. Furthermore, in the machining according to the present embodiment, the workpieces are not limited in shape. That is, applicable cases also include a case where a workpiece has a conical part or an arcuate part on its machining surface and a plurality of feed shafts (on a Z-axis and an X-axis) are required, and a case where a workpiece has a circular columnar shape or a cylindrical shape and a specific one feed shaft (on the Z-axis) is required.

[0012] The machine tool control device 1 according to the present embodiment includes, for example, a computer including a memory including a read-only memory (ROM) and a random access memory (RAM), a central processing unit (CPU), and a communication control unit, which are coupled to each other via a bus. The function and operation of each functional unit described later are achieved by the cooperation of the CPU and the memory mounted in the computer described above, and the control programs stored in the memory. Furthermore, the machine tool control device 1 may include, for example, a computer numerical control (CNC) or a programmable logic controller (PLC), or be coupled to a host computer that outputs machining conditions, including a rotational speed, in addition to a machining program.

[0013] As in Fig. 1, the machine tool control device 1 includes a machining condition detection unit 11, a machining determination unit 12, a thread amount control setting unit 13, a thread amount determination unit 20, a machining control unit 21, a storage unit 14, an input unit 15, and a display unit 16.

[0014] The machining condition acquisition unit 11 acquires the machining conditions and oscillation conditions for subjecting a workpiece to oscillation cutting. The machining conditions and oscillation conditions acquired by the machining condition acquisition unit 11 can be, for example, those stored in the storage unit 14 or those output from an external computer.

[0015] Example machining conditions include information about the thread form and the cutting conditions with respect to a workpiece. Example information about a thread form includes a thread pitch (mm), a thread diameter (mm), and a thread ridge angle (°). Example cutting conditions with respect to a workpiece include a rotational speed S (1 / min) of a main shaft, a finishing allowance (mm), a number of machining operations (number), and a thread position (mm). Example thread positions include, but are not particularly limited to, reference positions such as a position of one end (e.g., a position of a lower end) and a position of another end (a position of an upper end) in vibration directions. In addition, a thread position may be information with which it is possible to identify a thread position containing, for example, a cutting area.As described above, a thread amount can be a length, an area, or information to identify a position.

[0016] In addition, exemplary oscillation conditions include information related to a number of oscillations in the diameter directions of a workpiece and information related to an oscillation amplitude in the diameter directions of the workpiece. An example of information related to the number of oscillations in the diameter directions of the workpiece is an oscillation frequency multiplication factor I (multiplication), which indicates an oscillation frequency per revolution of the main shaft. An example of information related to an oscillation amplitude in the diameter directions of the workpiece, which is related to the cutting tool and the workpiece, is an oscillation amplitude multiplication factor K (multiplication), which indicates the magnitude of an oscillation amplitude with respect to a thread amount in the diameter directions of the workpiece in which threading takes place.

[0017] The machining determination unit 12 determines a type of machining to be performed based on the machining conditions detected by the machining condition detection unit 11. The machining determination unit 12 according to the first embodiment determines whether the machining to be performed is oscillation thread cutting or non-oscillation thread cutting based on the machining conditions.

[0018] The thread amount rule setting unit 13 sets a setting rule for determining a thread amount based on a determination result by the machining determination unit 12. For example, setting rules are set in advance to correspond to each machining type determined by the machining determination unit 12. The setting rules may be stored in the storage unit 14 or output from an external computer.

[0019] In a setting rule in the first embodiment, although the set thread amount is not changed in normal thread cutting without oscillation, the set thread amount is changed in oscillation cutting. A setting rule will be described later.

[0020] The thread amount determining unit 20 determines a thread amount used during actual machining based on a set thread amount included in the machining conditions and the setting rule that the thread amount rule setting unit 13 sets.

[0021] The machining control unit 21 generates an operation command based on the threading amount determined by the machining determination unit 20, and executes operation control based on the operation command. Under the operation control, for example, the motor 3 is driven, the workpiece and the cutting tool move, and thread cutting is performed.

[0022] The storage unit 14 stores various types of information for controlling and executing machining with the machine tool. In the present embodiment, the storage unit 14 stores the machining conditions and the oscillation conditions. Machining conditions and oscillation conditions are, for example, those that the operator has entered into a machining program or those that have been set as parameters for a machine tool. Note that the storage unit 14 does not have to be provided in the control device 1, but can also be arranged outside the control device.

[0023] The input unit 15 inputs, for example, machining information in accordance with an operator input via an input device (not shown) such as a keyboard or panel. The machining information input via the input unit 15 is stored, for example, in the storage unit 14 or input into each component of the control device 1.

[0024] The display unit 16 displays various types of information related to the machine tool, the control device 1, and the machining process. The display unit 16 includes, for example, a display.

[0025] A complete configuration of the control device 1 has already been described above. Next, a machining program for thread cutting without oscillation cutting will be described.

[0026] Fig. Figure 2 shows an example of a machining program in the first embodiment in which no oscillation cutting is performed. For example, the operator sets the Fig. 2 shown machining program.

[0027] In Fig. 2, "G76" represents the command of a block in the machining program and a code for generating a motion block during thread cutting that is executed multiple times. In addition, "Q" represents a code that specifies a thread amount for a first time, "P" represents a code that specifies the height of the thread burr, and "R" represents a code that specifies the angle of the thread burr. As thread cutting conditions (a thread pitch, a thread burr angle, and a specified thread amount), "G76 X9.0 Z10.0 F2.0" and "Q10.0 R60.0" are registered in the machining program. In this example, a thread amount X for the first thread cutting = 10.0 mm and a thread amount X for the second thread cutting = 9.0 mm are registered as the specified thread amounts.

[0028] Fig. Fig. 3 is a diagram showing a positional relationship between a workpiece and a cutting tool T when no oscillation cutting is performed in the first embodiment. When the Fig. 2 is executed, a work command is issued as shown in the Fig. 3. In this example, thread cutting without oscillation is performed twice, with thread amount X = 10.0 mm and thread amount X = 9.0 mm (fixed thread amounts) as thread amounts.

[0029] Next, a machining program is described that provides for oscillation thread cutting. Fig. Fig. 4 is a view showing an example of a machining program in oscillation cutting in the first embodiment. For example, the operator sets the Fig. 4 shown machining program.

[0030] In the Fig. 4, “G8.5 P3 I5.0 K2.0” is described, in addition to the machining programs described in Fig. 2. In the machining program, "G8.5 P3" indicates that a thread cutting oscillation mode is enabled. Furthermore, "I5.0 K2.0" following "G8.5 P3" specifies the oscillation conditions, including, for example, an oscillation frequency and an oscillation amplitude. In this example, an oscillation frequency of 5.0 [Hz] and an oscillation amplitude of 2.0 [mm] serve as the oscillation conditions.

[0031] In the first embodiment, when the machining conditions indicate that oscillation should be performed, similar or identical to that shown in Fig. 4, processing for resetting a thread amount is executed based on a previously set setting rule. Setting rules are previously set in the control device 1 based on priority. A first setting rule and a second setting rule that differ from each other in priority will be described here.

[0032] The first determination rule will now be explained with reference to the Fig. 5 and Fig. 6 described. Fig. 5 is a diagram showing the position of the workpiece and the cutting tool T when the first setting rule is applied and the thread amount is changed. Fig. Figure 6 is a diagram showing the position of the workpiece and the cutting tool T in oscillation cutting when the first setting rule is applied.

[0033] The first setting rule represents a rule to prioritize reducing the number of operations to shorten the cycle time and, in the case of oscillating tapping, to set a thread amount to achieve a lower number of executions than in normal tapping.

[0034] In the Fig. In the example shown in Figure 5, specified thread positions are recorded from a machining program, which state that a thread burr position is 11.0 mm, a specified thread position is 10.0 mm and a thread position that serves as the end position is 9.0 mm.

[0035] Next, the thread amount determination unit 20 acquires the number of positions to be deleted from the setting rule set by the thread amount rule setting unit 13 and a deletion method. In this example, it is assumed that a rule for deleting the even number of threads applies. The thread amount determination unit 20 deletes the thread amounts for the even-numbered positions counted from the thread land position according to the setting rule. That is, among the set thread amounts during thread cutting to be executed twice when there is no oscillation, the thread amount X = 10 mm is omitted the first time. As shown in Fig. As shown in Figure 6, the oscillation thread cutting and the thread cutting without oscillation the second time are based only on the thread amount X = 9.0 mm.

[0036] The second determination rule will now be explained with reference to the Fig. 7 and Fig. 8 described. Fig. 7 is a diagram showing the position of the workpiece and the cutting tool T when the second setting rule is applied and the thread amount is changed. Fig. 8 is a diagram showing the position between the workpiece and the cutting tool T in oscillation cutting when the second setting rule is applied.

[0037] The second setting rule represents a rule to prioritize reducing the load on the workpiece and the cutting tool T per operation and, in the case of oscillating thread cutting, to set a thread amount to achieve a higher number of executions than in normal thread cutting.

[0038] Also in the Fig. In the example shown in Figure 7, specified thread positions are acquired from a machining program, indicating that a thread burr position is 11.0 mm, a specified thread position is 10.0 mm, and a thread position serving as an end position is 9.0 mm.

[0039] Next, the thread amount determination unit 20 acquires the number of thread positions to be added based on the determination rule determined by the thread amount rule determination unit 13, and a method for adding the thread positions. In this example, it is a determination rule for adding the thread positions at intermediate positions between the acquired thread positions. A thread amount X = 10.5 mm is added between the thread burr position of 11.0 mm and the thread amount X = 10 mm, and a thread amount X = 9.5 mm is added between the thread amount X = 10 mm and the thread amount 9.0 mm. That is, a total of four thread amounts are determined: the first added thread amount X = 10.5 mm, the second added thread amount X = 10.0 mm, the third added thread amount X = 9.5 mm, and the fourth added thread amount X = 9.0 mm.As described above, in oscillation tapping, the thread amounts for two times are further added to the specified thread amounts so that thread cutting can be performed twice even without oscillation. As shown in . Fig. As shown in Figure 8, the oscillation thread cutting and the thread cutting without oscillation are then carried out for the thread amount X = 10.5 mm, the thread amount X = 10.0 mm, the thread amount X = 9.5 mm and the thread amount X = 9.0 mm, respectively.

[0040] Note that although the second setting rule stipulates that the thread amounts are added according to the positions of the set thread amounts, the present disclosure is not limited to this manner, and a thread amount may be set in accordance with a predetermined index. For example, instead of a position of a set thread amount, a thread position may be added to enable a constant maximum cutting amount in each thread. It is possible to calculate the thread amount from the maximum cutting amount using a known method. In this example, oscillation tapping and non-oscillation tapping are performed for the first time with a thread amount added X = 10.4 mm, the second time with a thread amount added X = 10.0 mm, the third time with a thread amount added X = 9.4 mm, and the fourth time with a thread amount added X = 9.0 mm.

[0041] Furthermore, under the second setting rule, a thread position can be added for each thread amount according to a predetermined maximum cutting amount, which is set for each thread cutting. In this example, instead of the predetermined thread amount, a predetermined maximum cutting range is set in the control device 1. The maximum cutting range referred to here is a cutting range at which a thread position has reached a lowest position during oscillation. Within the setting rule, a known method is used to calculate a predetermined thread amount for achieving a maximum cutting range, and a thread position is added between the thread positions.

[0042] Next, a flow of processing for generating a thread cutting command will now be described with reference to Fig. 9 described. Fig. 9 is a flowchart showing an example of generation of a thread cutting command by the machine tool control device.

[0043] As in Fig. As shown in Figure 9, the machining condition acquisition unit 11 acquires the thread cutting conditions for thread cutting when the operator instructs the start of machining (step S10). The thread conditions include, for example, a thread pitch and oscillation conditions as described above. Furthermore, the thread conditions are acquired, as described above, from, for example, a machining program stored in the storage unit 14 or parameters set for the machine tool.

[0044] Next, in step S11, the machining determination unit 12 determines whether a specific machining mode (oscillation thread cutting) is present based on the machining conditions (step S11). In the first embodiment, if oscillation thread cutting is present (step S11; Yes), the machining determination unit 12 causes machining to proceed to step S12, and if non-oscillation thread cutting is present (step S11; No), the machining to proceed to step S20.

[0045] The following describes a case where oscillation thread cutting is determined. In step S12, the thread amount rule setting unit 13 sets a setting rule based on a result of the determination by the machining determination unit 12, and the thread amount determination unit 20 newly sets a thread amount for oscillation thread cutting based on a set thread amount and the setting rule (see Fig. 5 and Fig. 7).

[0046] After step S12, the machining control unit 21 generates a thread cutting command for the oscillation cutting based on the thread amount determined by the thread amount determination unit 20 (step S13), and the oscillation thread cutting is executed (step S14).

[0047] Next, a case where non-oscillation thread cutting is determined will be described. In step S20, the thread amount rule setting unit 13 sets a setting rule based on a result of the determination by the machining determination unit 12, and the thread amount determination unit 20 sets a specified thread amount as the thread amount for normal non-oscillation cutting.

[0048] Next, the machining control unit 21 generates a normal thread cutting command based on the thread amount determined by the thread amount determining unit 20 (step S21), and the normal thread cutting without oscillation is executed (step S22).

[0049] With the machine tool control device 1 according to the first embodiment, which performs thread cutting on the workpiece with the cutting tool T as described above, the effects described below are achieved.

[0050] The machine tool control device 1 according to the present embodiment includes: the machining condition acquisition unit 11 that acquires the machining conditions for thread cutting; the machining determination unit 12 that determines a machining type from the machining conditions; the rule setting unit 13 that determines a setting rule, which is a method for setting a thread amount for thread cutting, based on a determination result by the machining determination unit 12; and the thread amount determination unit 20 that determines a thread amount used during machining based on the machining conditions and the setting rule. This automatically sets a thread amount that reflects the operator's priority, and thread cutting is performed according to the current situation.For example, when a cycle time is to be shortened, setting a setting rule for adjusting a thread amount to reduce the number of machining times enables a shortened cycle time because it is possible to cool the machining heat at the cutting tool T when air cutting is performed (which is described in the . Fig. 5 and Fig. 6). If the load on the cutting tool T during machining is to be reduced, by setting a setting rule for setting a thread amount to increase the number of machining operations, the load on the cutting tool T can be reduced (which is shown in the Fig. 7 and Fig. 8 examples shown).

[0051] Furthermore, according to the present embodiment, the machining determination unit 12 determines, based on the machining conditions, machining in which oscillation cutting should be performed or machining in which oscillation cutting should not be performed, and the thread amount rule setting unit 13 determines a setting rule according to whether oscillation should be performed. This identifies oscillation cutting, which has a great influence on the cycle time and the cutting tool T, so that it is possible to perform thread cutting based on a thread amount suitable for oscillation tapping.

[0052] Furthermore, according to the present embodiment, the machining determination detection unit 11 detects a predetermined thread amount, and the thread amount determination unit 20 determines a thread amount used during machining based on the predetermined thread amount and the determination rule. Thus, even if a thread amount has been predetermined, it is automatically adjusted to a thread amount that reflects the operator's priority, making highly productive and safe thread cutting easy.

[0053] Furthermore, according to the present embodiment, in a case where oscillation cutting is determined, the thread amount rule setting unit 13 sets a setting rule for adding a thread position between a plurality of thread positions that the machining condition acquisition unit 11 acquires from the machining conditions. Based on the setting rule, the thread amount determination unit 20 sets a set thread amount or a thread amount corresponding to the maximum cutting amount to keep a thread cutting interval or a maximum thread cutting amount constant. This automatically sets a work command that prioritizes reducing the load on the workpiece or the cutting tool T per machining operation, so that machining that meets the operator's requirements is easily possible.

[0054] Furthermore, the thread amount rule setting unit 13 according to the present embodiment determines a setting rule to delete at least one of a plurality of thread positions indicated by the set thread amount. This automatically sets a work command that prioritizes reducing the number of machining operations to shorten the cycle time, so that machining that meets the operator's requirements is easily possible.

[0055] Although the control device 1 for the machine tool according to the first embodiment has been described above, the present disclosure is not limited to the configuration of the above-described embodiment. For example, a setting rule is not limited in content to those described in the above-described embodiment, and it is possible to change a method for setting a thread amount according to each of various conditions. Embodiments different from the above-described embodiment will be described below. [Second embodiment]

[0056] Next, a control device 1 according to a second embodiment will be described. Note that a basic configuration of the control device 1 according to the second embodiment is the same as that shown in Fig. 1 shown configuration.

[0057] In the second embodiment, instead of a machining program, a threading amount per unit time is preset in the control device 1. The threading amount is stored, for example, in the storage unit 14 as a parameter set in the control device 1 for the machine tool. In the present embodiment, a predetermined threading amount is set to 0.7 mm.

[0058] The machining condition acquisition unit 11 acquires information indicating a thread position from the machining conditions. For example, the machining condition acquisition unit 11 acquires a thread burr position of 11.0 mm and a final position (a target position) of 9.0 mm as information indicating the thread position.

[0059] Also in the second embodiment, when the machining conditions indicate that oscillation should be performed, the control device 1 performs processing for re-setting a thread amount based on a previously set setting rule.

[0060] A setting rule according to the second embodiment will now be described with reference to Fig. 10 described. Fig. 10 is a diagram showing the position between the workpiece and the cutting tool T when applying a setting rule and setting a thread amount in the second embodiment. Within the setting rule, a thread amount is set based on a thread position, which is a thread position detected by the machining conditions, a final position, and a predetermined thread amount.

[0061] In the Fig. In the example shown in Figure 10, a thread amount for oscillation cutting is specified by subtracting the predetermined thread amount from the thread land position of 11.0 mm to the end position (target position) of 9.0 mm. In this example, 10.3 mm, which is obtained by subtracting the predetermined thread amount of 0.7 from the thread land position of 11.0 mm, is set as the thread amount for the first thread cutting. Next, 9.6 mm, which is obtained by subtracting the predetermined thread amount of 0.7 from 10.3 mm, is set as the thread amount for the second thread cutting. Since subtracting the predetermined thread amount of 0.7 from 9.6 mm is 8.9 and thus exceeds the target position of 9.0 mm, the target position of 9.0 mm is set as the thread position for the third thread cutting.Then, the oscillation thread cutting and the non-oscillation thread cutting are performed for the specified thread amount of 10.3 mm, the specified thread amount of 9.6 mm and the specified thread amount of 9.0 mm, respectively.

[0062] Note that in the second embodiment, a thread amount was specified according to a predetermined thread amount. However, the present disclosure is not limited to this embodiment, and a thread amount may be determined according to a predetermined index. For example, such a means as described below may be used. Instead of the predetermined thread amount, a predetermined maximum cutting range is set in the control device 1. The maximum cutting range referred to here is a cutting range at which a thread position has reached a lowest position during oscillation. As a setting rule, a known method for calculating a predetermined thread amount is used to achieve a maximum cutting range. A method for setting a thread amount for oscillation cutting is similar to or identical to the method described above.Also in this example, oscillation thread cutting and non-oscillation thread cutting are performed for the specified thread amount of 10.3 mm, the specified thread amount of 9.6 mm and the specified thread amount of 9.0 mm, respectively.

[0063] With the machine tool control device 1 according to the second embodiment, which performs thread cutting on the workpiece with the cutting tool T as described above, the effects described below are achieved.

[0064] In the present embodiment, for machining operations that the machining determination unit 12 determines as specific machining operations, a setting rule for setting the thread amount is set according to a predetermined thread amount or a predetermined maximum cutting area. Therefore, even if a predetermined thread amount or a predetermined maximum cutting area has been set, an operation command corresponding to an operator's request is automatically set. [Third Embodiment]

[0065] Next, a control device 1a according to a third embodiment will now be described with reference to Fig. 11 described. Fig. Figure 11 is a functional block diagram of the control device 1a for the machine tool according to the third embodiment. In the third embodiment, the control device 1a differs from the above-described embodiments in that it includes a sensor 30 that measures, for example, the temperature of the cutting tool T for threading or a drive motor, and other components are common to those of the above-described embodiments.

[0066] In the control device 1a according to the third embodiment, a setting rule similar to or identical to the first setting rule according to the first embodiment is set. Within the setting rule, the sensor 30 detects a current machining state (a current temperature) at a time when the cutting tool T is positioned at a starting point. In a thread amount determining unit according to the third embodiment, when a result of detection by the sensor 30 indicates that there is no margin in the machining state, such as a completely low temperature, processing for canceling a thread position for machining for a next time and later is performed. For example, when the temperature is below a certain value, a process for deleting a thread position is executed.As described above, such a configuration can be made so that a setting rule is changed according to the state of processing. [Fourth Embodiment]

[0067] Next, a control device 1b according to a fourth embodiment will now be described with reference to Fig. 12 described. Fig. 12 is a functional block diagram of the control device 1b for the machine tool according to the fourth embodiment. In the fourth embodiment, the control device 1b differs from the above-described embodiments in that it includes an upper limit value detection unit 31, and other components are common to those of the above-described embodiments.

[0068] In the fourth embodiment, the upper limit detection unit 31 detects an upper limit value related to cutting. The upper limit value may be, for example, an upper limit value for the threading amount, an upper limit value for a cutting amount, or an allowable load during cutting. The upper limit value is set taking into account an instantaneous maximum value when performing oscillation. The upper limit value is stored in the storage unit 14 as a parameter for a machining program or the control device 1 for the machine tool. Note that the upper limit value may also be stored in an external device.

[0069] A thread amount determination unit 20b according to the fourth embodiment determines a thread amount for actual thread cutting, taking into account the upper limit value detected by the upper limit value detection unit 31. That is, if the upper limit value of any of the thread amount, the cutting amount, or the allowable load during cutting has been exceeded, a correction is performed as a result of the setting rule so that the thread amount is equal to or less than the upper limit value.Otherwise, no setting rule for setting a thread amount according to a predetermined thread amount or a predetermined maximum cutting range may be set, and a setting rule for setting a thread amount may be provided to perform machining with an upper limit of a thread amount, a cutting amount, and an allowable load during cutting per thread.

[0070] With the machine tool control device 1b according to the fourth embodiment, which performs thread cutting on the workpiece with the cutting tool T as described above, the effects described below are achieved.

[0071] The control device 1b according to the present embodiment further includes the upper limit value detection unit 31 that detects an upper limit value related to cutting, and the thread amount detection unit that determines a thread amount reflecting the upper limit value in addition to the machining conditions and the setting rule. Therefore, even if the thread amount changes, similar to or identical to oscillation tapping, an upper limit value is automatically incorporated into a work command, enabling highly reliable thread cutting without requiring separate setting by an operator. Otherwise, it is possible to perform machining with an upper limit value per thread, enabling highly efficient thread cutting.

[0072] Note that, although in the above-described embodiments and modification examples, the examples have been introduced in which, as a format for a machining program, a code for generating a motion block in thread cutting to be repeated a plurality of times with a command of a block in a machining program, such as “G76”, is used, the present technique is also applicable to a case in which, for example, the Fig.3 is programmed twice using a code "G92" to generate one operation in one cycle (starting point, X-axis positioning, thread cutting, and returning to the starting point) of thread cutting, and a case where such an operation is programmed by combining a positioning code "G00" and a thread cutting code "G32" and executing one cycle of thread cutting twice. In this case, a thread amount used during machining may be determined according to a predetermined thread position detected by a machining program, or, similarly or identically to the second embodiment, a thread burr position and an end position may be detected to determine a thread amount used during machining.

[0073] Although the above-described embodiments and modification examples described the example in which the machining determination unit 12 determines oscillation thread cutting or non-oscillation thread cutting as the specific machining, the present disclosure is not limited to this configuration. For example, a configuration in which ultrasonic machining is identified as a specific function may be adopted. Furthermore, a configuration in which machining with a specific tool having higher wear resistance is identified, and a determination rule that takes wear resistance into account is applied to the machining may be adopted.

[0074] Although in the embodiments described above, a command for alternately repeating oscillation tapping and non-oscillation tapping is automatically generated, the present disclosure is not limited to these embodiments. For example, it may be configured so that after oscillation tapping is performed multiple times, non-oscillation tapping is performed at least once. In this case, it is advantageous to control the machining so that the oscillation conditions are set so that the top and bottom of the continuous oscillation tapping can overlap. For example, the machining control unit 21 performs machining to shift the phase of an oscillation condition by 180 degrees so that the top and bottom of the oscillation tapping can overlap.

[0075] Although the present disclosure has been described in detail, the present disclosure is not limited to each of the above-described embodiments. Various additions, replacements, changes, and partial deletions can be made in the embodiments without departing from the gist of the present disclosure or the scope of the present disclosure, which is understood from the contents described in the claims and their equivalents. Furthermore, it is possible to implement the embodiments in a combined manner. For example, in the above-described embodiments, the order of operations and the order of processing steps are given merely as examples, and the present disclosure is not limited to the embodiments.The same applies to cases where a numerical value or a numerical expression is used to describe the embodiments described above.

[0076] Further, additional remarks are disclosed in relation to the above-described embodiments and modification examples, which will be described below. (Additional Note 1)

[0077] The control device (1, 1a, 1b) for the machine tool that performs thread cutting on a workpiece using the cutting tool (T), includes: a machining condition acquisition unit (11) that acquires machining conditions for thread cutting; a machining determination unit (12) that determines a type of machining from the machining conditions; a thread amount rule setting unit (13) that determines a setting rule, which is a method for setting a thread amount for thread cutting, based on a result of determination by the machining determination unit; and a thread amount determination unit (20, 20a, 20b) that determines a thread amount used during machining based on the machining conditions and the setting rule. (Additional Note 2)

[0078] In the above-described machine tool control device (1, 1a, 1b), the machining determination unit (12) determines whether machining in which oscillation cutting is to be performed or machining in which oscillation cutting is not to be performed based on the machining conditions, and the thread amount rule setting unit (13) determines the setting rule according to whether oscillation cutting is to be performed or not. (Additional Note 3)

[0079] In the above-described machine tool control device (1, 1a, 1b), the machining condition detecting unit (11) detects a predetermined thread amount, and the thread amount determining unit (20, 20a, 20b) determines the thread amount used during machining based on the predetermined thread amount and the determination rule. (Additional Note 4)

[0080] In the above-described machine tool control device (1, 1a, 1b), in a case where it is determined that oscillation is performed, the thread amount rule setting unit (13) sets a setting rule for adding a thread position between a plurality of thread positions detected by the machining condition detecting unit (11), and the thread amount determining unit (20, 20a, 20b) sets, to make a predetermined index constant, a thread amount in accordance with the predetermined index based on the setting rule. (Additional Note 5)

[0081] In the above-described machine tool control device (1, 1a, 1b), the thread amount rule setting unit (13) determines a setting rule for deleting at least one of a plurality of thread positions indicated by the set thread amount. (Additional Note 6)

[0082] In the above-described machine tool control device (1, 1a, 1b), for the machining which the machining determination unit (12) determines as a specific machining, a setting rule for setting each thread amount according to a predetermined index is set, and the thread amount is determined. (Additional Note 7)

[0083] In the above-described machine tool control device (1b), an upper limit value detecting unit (31) is further included which detects an upper limit value related to machining, wherein the thread amount determining unit (20b) determines a thread amount in which the upper limit value is reflected in addition to the machining conditions and the setting rule. Explanation of reference symbols 1, 1a, 1b Control device for machine tool 11 Machining condition acquisition unit 12 Processing determination unit 13 Thread amount control setting unit 20, 20a, 20b Thread amount determination unit 31 Upper limit value recording unit T cutting tool 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 2020-66169

[0004]

Claims

[1] A control device for a machine tool that performs thread cutting on a workpiece using a cutting tool, the control device for the machine tool comprising: a machining condition acquisition unit that acquires machining conditions for thread cutting; a processing determination unit that determines a type of processing from the processing conditions; a thread amount rule setting unit that determines a setting rule based on a result of the determination by the machining determination unit, which is a method for setting a thread amount for thread cutting; and a thread amount setting unit that determines a thread amount used during machining based on the machining conditions and the setting rule. [2] The control device for a machine tool according to claim 1, wherein the machining determination unit determines, from the machining conditions, the machining in which oscillation cutting is to be performed or the machining in which oscillation cutting is not to be performed, and the thread amount rule setting unit sets the setting rule in accordance with whether or not oscillation is to be performed. [3] The control device for a machine tool according to claim 1 or 2, wherein the machining condition detecting unit detects a predetermined thread amount, and the thread amount determining unit determines the thread amount used during machining based on the predetermined thread amount and the determination rule. [4] The control device for a machine tool according to claim 3, wherein, in a case where it is determined that oscillation is performed, the thread amount rule setting unit sets a setting rule for adding a thread position between a plurality of thread positions that the machining condition detecting unit detects from the machining conditions, and the thread amount determining unit for allowing a predetermined index to be constant sets a thread amount in accordance with the predetermined index based on the setting rule. [5] The control device for a machine tool according to claim 3, wherein the thread amount rule setting unit determines a setting rule to cancel at least one of a plurality of thread positions indicated by the set thread amount. [6] The control device for a machine tool according to claim 1 or 2, wherein, for machining which the machining determination unit determines as a specific machining, a setting rule for setting the thread amount is determined for each thread amount in accordance with a predetermined index. [7] The control device for a machine tool according to any one of claims 1 to 6, further comprising an upper limit value detecting unit that detects an upper limit value related to cutting, wherein the thread amount determining unit determines a thread amount into which the upper limit value is incorporated in addition to the machining conditions and the setting rule.

Images