Machine tool control device and machine tool display device

Abstract

Provided is a technology capable of reliably carrying out air cutting during oscillation machining for threading regardless of oscillation phase differences. This machine tool control device 1 comprises: a condition acquisition unit 11 for acquiring, as a precondition, one or two pieces of information among three pieces of information, namely, an oscillation phase difference, information regarding a workpiece radial cut depth, and information regarding a radial oscillation amplitude of the workpiece; an air cut amount acquisition unit 12 for acquiring a specified air cut amount indicating the degree of air cut in the oscillation direction; and a machining control unit 13 for determining (a) piece(s) of information not acquired by the condition acquisition unit 11 among the three pieces of information on the basis of the precondition and carrying out machining control such that an air cut amount based on the interval between the n-th threading path and a threading path subsequent to the n-th path matches the specified air cut amount.

Description

[Technical Field]

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

[0002] Conventionally, to prevent chips, which are continuously generated during machining, from becoming entangled in the workpiece or cutting tool, which can cause machining defects or machine failure, workpieces are machined by swinging the tool and workpiece relative to each other.

[0003] In this type of swing machining, a technique is known in which the tool path, which is the trajectory of the tool, is set to overlap partially with the previous tool path, causing the tool to move away from the surface of the workpiece, generating a missed swing known as an air cut, thereby shredding the chips (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6709163 Summary of the Invention [Problem to be solved by the invention]

[0005] In oscillating machining for turning, the phase difference changes depending on the set frequency magnification, but in oscillating machining for thread cutting, the phase difference between the previous pass and the current pass can be determined arbitrarily by the control device. However, if the frequencies of the previous pass and the current pass are not the same, the air cut will not be consistent each time, so for efficiency reasons, the oscillating phase difference is set to 180 degrees.

[0006] The technology described in Patent Document 1 sets the oscillation amplitude based on the amount of misses, but like the conventional technology, it is based on the premise that the oscillation phase difference between the previous pass and the current pass is 180 degrees, so there is room for improvement in terms of appropriately performing misses even when the oscillation phase difference is other than 180 degrees.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a technology that can reliably perform air cutting in thread cutting oscillation processing regardless of the oscillation phase difference. [Means for solving the problem]

[0008] The present disclosure relates to a control device for a machine tool that performs thread cutting using a cutting tool that oscillates relative to a workpiece, the control device for a machine tool comprising: a condition acquisition unit that acquires, as preconditions, one or two of three pieces of information: an oscillation phase difference that acquires the oscillation phase difference between an nth thread cutting pass and a thread cutting pass after the nth, information regarding the radial depth of cut of the workpiece, and information regarding the oscillation amplitude in the radial direction of the workpiece; an air cut amount acquisition unit that acquires a specified air cut amount that indicates the degree of air cut in the oscillation direction; and a machining control unit that determines, based on the preconditions, the information of the three pieces of information that has not been acquired by the condition acquisition unit, and performs machining control, so that the air cut amount based on the nth thread cutting pass and a thread cutting pass after the nth becomes the specified air cut amount.

[0009] The present disclosure also provides a display device for a machine tool that performs thread cutting using a cutting tool that oscillates relative to a workpiece, the display device for the machine tool comprising: a condition input unit that accepts input of one or two pieces of information as preconditions out of three pieces of information: the oscillation phase difference between the nth thread cutting pass and thread cutting passes after the nth, information regarding the radial cutting amount of the workpiece, and information regarding the oscillation amplitude in the radial direction of the workpiece; an air cut amount input unit that accepts input of a specified air cut amount that indicates the degree of air cut in the oscillating direction; an information calculation unit that calculates the information out of the three pieces of information that is not accepted by the condition input unit based on the preconditions so that the air cut amount based on the relationship between the nth thread cutting pass and thread cutting passes after the nth becomes the specified air cut amount; and a display unit that displays the calculated information of the information calculation unit. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a technology that can reliably perform air cutting in thread cutting oscillation processing regardless of the oscillation phase difference. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a functional block diagram of a control device for a machine tool according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing conditions acquired by a condition acquisition unit of the present embodiment. [Figure 3] FIG. 10 is a diagram illustrating an example of a machining program. [Figure 4] 1 is a graph showing the positional relationship between a workpiece and a cutting tool. [Figure 5] FIG. 10 is a functional block diagram of a display device of a machine tool according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0013] FIG. 1 is a functional block diagram of a machine tool control device 1 according to one embodiment of the present invention. The machine tool control device 1 according to one embodiment of the present invention is used to perform thread cutting using a cutting tool that oscillates radially relative to a workpiece. For convenience, FIG. 1 only shows a motor 3 that drives one feed axis. Furthermore, the cutting process according to this embodiment is not limited to a specific shape of the workpiece. That is, the present invention is applicable to cases where the workpiece has a tapered or arc-shaped portion on the cutting surface, requiring multiple feed axes (Z-axis and X-axis), and cases where the workpiece is columnar or cylindrical, and only one specific feed axis (Z-axis) is sufficient.

[0014] The machine tool control device 1 of this embodiment is configured using a computer including memories such as ROM (read only memory) and RAM (random access memory), a CPU (control processing unit), and a communication control unit, all connected to one another via a bus. The functions and operations of the above functional units are achieved by the cooperation of the CPU and memory installed in the computer and the control program stored in the memory. The machine tool control device 1 may also be configured with a CNC (Computer Numerical Controller) or PLC (Programmable Logic Controller), or may be connected to a higher-level computer that outputs machining conditions such as rotation speed in addition to the machining program.

[0015] As shown in FIG. 1, the machine tool control device 1 includes a condition acquisition unit 11, an air cut amount acquisition unit 12, a machining control unit 13, a memory unit 14, an input unit 15, and a display unit 16.

[0016] The condition acquisition unit 11 acquires machining conditions and oscillation conditions for oscillating machining of a workpiece. The machining conditions and oscillation conditions may be, for example, those stored in the storage unit 14, or may be those output from an external computer.

[0017] Here, the machining conditions include at least information regarding the relative feed rate per revolution between the cutting tool and the workpiece, and information regarding the shape of the cutting tool cutting edge, as well as information regarding, for example, the spindle rotation speed S (1 / min), the cutting tool feed rate (mm / min), the workpiece diameter (mm), the cutting tool clearance angle (°), etc. Note that examples of information regarding the relative feed rate per revolution between the cutting tool and the workpiece include the feed rate per revolution F (mm / rev) and the combination of the spindle rotation speed S (1 / min) and the cutting tool feed rate (mm / min), and examples of information regarding the shape of the cutting tool cutting edge include the cutting edge R (mm).

[0018] The oscillation conditions include information about the number of oscillations in the radial direction of the workpiece and information about the oscillation amplitude in the radial direction of the workpiece. Information about the number of oscillations in the radial direction of the workpiece includes an oscillation frequency magnification I (times), which indicates the oscillation frequency per rotation of the spindle. Information about the oscillation amplitude in the radial direction of the workpiece relative to the cutting tool and workpiece includes an oscillation amplitude magnification K (times), which indicates the magnitude of the oscillation amplitude relative to the cutting depth in the radial direction of the workpiece during thread cutting.

[0019] The air cut amount acquisition unit 12 acquires a designated air cut amount designated in advance by an operator, etc. The air cut amount may be, for example, stored in the storage unit 14, acquired from an external computer, or input via the input unit 15.

[0020] The air cut amount referred to here is the air cut amount between the nth thread cutting pass and the thread cutting pass after the nth thread cutting pass (n+1 or later). In this embodiment, the air cut amount between the nth thread cutting pass and the (n+1)th thread cutting pass is used to determine the machining conditions. Note that the air cut amount between the nth thread cutting pass and the (n+2)th thread cutting pass may also be used to determine the machining conditions.

[0021] In this embodiment, the distance in the oscillation direction is used as the air cutting amount. In this embodiment, since the workpiece oscillates in the radial direction, the air cutting amount is a numerical value that indicates the degree of air cutting in the radial direction of the workpiece. The air cutting amount may be any index that indicates the magnitude of air cutting, and may be expressed as the distance in the oscillation direction, an area including the oscillation direction, a level linked to the air cutting amount determined in advance in a table, or a multiplication factor relative to an arbitrary reference value (for example, the cutting depth).

[0022] The machining control unit 13 controls machining so that the air cut amount after machining starts becomes the designated air cut amount based on the conditions acquired by the condition acquisition unit 11. Details of machining control by the machining control unit 13 will be described later.

[0023] The memory unit 14 stores various information for controlling and machining the machine tool. In this embodiment, the memory unit 14 stores machining conditions, swing conditions, and an air cut amount specified by an operator. The machining conditions, swing conditions, and air cut amount are, for example, input by the operator into a machining program or specified as machine tool parameters. The memory unit 14 may be configured to be located outside the control device 1 rather than inside it.

[0024] The input unit 15 inputs information related to processing in response to an operator's input operation on an input means (not shown), such as a keyboard or a touch panel. The information related to processing input by the input unit 15 is stored in the storage unit 10 or the like, or input to each unit of the control device 1.

[0025] The display unit 16 displays various information relating to the machine tool, the control device 1, and machining.

[0026] Next, the conditions acquired by the condition acquisition unit 11 and the processing control by the processing control unit 13 will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the conditions acquired by the condition acquisition unit 11 of this embodiment.

[0027] 2, the condition acquisition unit 11 includes a phase difference acquisition unit 21 and a cutting depth acquisition unit 22. The phase difference acquisition unit 21 acquires the oscillation phase difference set in the control device 1 of the machine tool as a thread cutting condition. The cutting depth acquisition unit 22 acquires the cutting depth for the thread cutting as a thread cutting condition.

[0028] Next, an example of control by the control device 1 of this embodiment will be described. Fig. 4 is a graph showing the positional relationship between the workpiece and the cutting tool T. The machining program shown in Fig. 3 is one in which various information is specified by the operator via the input unit 15 or the like.

[0029] The graph in Figure 4 shows the positional relationship between the workpiece and cutting tool T. The machining control unit 13 determines the oscillation amplitude so that the air cut amount between the previous pass, which is the nth cutting pass, and the current pass, which is the (n+1)th cutting pass, becomes the specified air cut amount. The oscillation amplitude is in the same direction as the X-axis direction, which is also the cutting direction of the workpiece.

[0030] In the machining program in Figure 3, the "S1000 M03" block is a statement that indicates that the spindle is to rotate in the forward direction. The "G8.5 P3L0.02" block contains "L0.02", which indicates the specified air cut amount. The "G92 X10.0 Z10.00 F2.0" block and the "G92 X9.7 Z10.00 F2.0" block can obtain the cutting depth from the difference in the X coordinate.

[0031] When machining operation is started, the condition acquisition unit 11 of the control device 1 acquires the oscillation phase difference held as a setting of the control device 1 of the machine tool. In this example, a phase difference of 90 degrees is set in the control device 1. The condition acquisition unit 11 acquires the oscillation phase difference of 90 degrees.

[0032] The condition acquisition unit 11 also acquires the cutting depth from the machining program. In the example of FIG. 3, the cutting depth is calculated as 10.0-9.7=0.3 [mm] from "X10.0" and "X9.7" and acquired. The air cut amount acquisition unit 12 also acquires the designated air cut amount. In the example of FIG. 3, the air cut amount acquisition unit 12 acquires the designated air cut amount of 0.02 [mm] from "L0.02".

[0033] The machining control unit 13 determines the oscillation amplitude for thread cutting using the following formula based on the oscillation phase difference and cutting depth, which are the conditions acquired by the condition acquisition unit 11, and the designated air cut amount acquired by the air cut amount acquisition unit 12. In this example, the phase angle 90[°], cutting depth 0.3[mm], and designated air cut amount = 0.02[mm] are substituted.

[0034]

number

[0035] In formula (1), I represents the frequency magnification [times], L represents the specified air cut amount [mm], A represents the oscillation amplitude [mm], and θ represents the phase of the workpiece [°] at which the air cut amount becomes L.

[0036] The processing control unit 13 outputs information indicating the calculated oscillation amplitude to the display unit 16. The display unit 16 communicates the oscillation amplitude to the operator by using text information, graphic information, or a combination thereof indicating the oscillation amplitude.

[0037] The control device 1 for a machine tool that performs thread cutting using a cutting tool T that swings relatively to a workpiece according to the present embodiment described above provides the following effects.

[0038] The machine tool control device 1 according to this embodiment includes a condition acquisition unit 11 that acquires one or two of three pieces of information as preconditions: the oscillation phase difference between the nth thread cutting pass and thread cutting passes after the nth, information regarding the radial cutting depth of the workpiece, and information regarding the oscillation amplitude in the radial direction of the workpiece. An air cut amount acquisition unit 12 acquires a designated air cut amount indicating the degree of air cut in the oscillation direction. A machining control unit 13 determines the information not acquired by the condition acquisition unit 11 based on preconditions so that the air cut amount between the nth thread cutting pass and thread cutting passes after the nth matches the designated air cut amount, and performs machining control. This allows for accurate determination of whether chip shredding is possible even when the machining conditions change during thread cutting. Furthermore, by specifying a margin based on the designated air cut amount, appropriate missed strikes can be achieved even when the oscillation phase difference is not 180 degrees.

[0039] The condition acquisition unit 11 of this embodiment acquires, of the three pieces of information, the information on the swing phase difference and the depth of cut as preconditions, and the machining control unit 13 determines information on the swing amplitude based on the information on the swing phase difference and the depth of cut so that the air cut amount based on the relationship between the nth thread cutting pass and any thread cutting pass after the nth thread cutting pass becomes the specified air cut amount. This makes it possible to accurately calculate the swing amplitude corresponding to the specified air cut amount even if the swing phase difference is not 180 degrees.

[0040] Moreover, the control device 1 of this embodiment further includes a display unit 16 that outputs information determined by the machining control unit 13. This allows the operator to easily check safety and production plans based on the calculation results of the machining control unit 13, such as the oscillation amplitude.

[0041] In the above embodiment, the machining control unit 13 calculates the oscillation amplitude, but it may be configured to determine an amplitude magnification instead of the oscillation amplitude. In this case, in the control stage, the amplitude is determined from the cutting depth in the radial direction of the workpiece in thread cutting and the amplitude magnification, and control is performed using that amplitude.

[0042] The machining control unit may also be configured to determine information different from information regarding the oscillation amplitude depending on the conditions acquired by the condition acquisition unit. For example, the condition acquisition unit may acquire information regarding the oscillation phase difference and the oscillation amplitude, and the machining control unit may determine information regarding the cutting amount based on the information regarding the oscillation phase difference and the oscillation amplitude. Alternatively, the condition acquisition unit may acquire information regarding the oscillation phase difference, information regarding the cutting amount, and specific information identifying information regarding the oscillation amplitude, and the machining control unit may determine information regarding the cutting amount and information regarding the oscillation amplitude based on the oscillation phase difference and the specific information. Alternatively, the condition acquisition unit may acquire information regarding the oscillation amplitude, information regarding the cutting amount, and specific information identifying the oscillation phase difference, and the machining control unit may determine information regarding the cutting amount and the oscillation phase difference based on the information regarding the oscillation amplitude and the specific information. Specific numerical values ​​can be calculated using, for example, Equation (1).

[0043] The above-mentioned specific information may include, for example, a specified upper limit of the oscillation amplitude, an upper limit of the speed, an upper limit of the acceleration, an upper limit of the jerk, etc. The oscillation amplitude can be uniquely identified by these and the oscillation frequency. Furthermore, the specific information may be a recommended value for the oscillation phase difference, and the oscillation phase difference can be uniquely determined even when the setting is to operate at the recommended value. Furthermore, the specific information may be an upper limit of the cutting depth in the radial direction of the workpiece, and by setting the cutting depth in the radial direction of the workpiece to always be the upper limit, the cutting depth in the radial direction of the workpiece can be uniquely identified. Furthermore, a plurality of these exemplified specific information may be combined. In this way, the specific information is a rule set in the machine tool, and may be any information that the machining control unit 13 can identify.

[0044] The above-described determination method and calculation method are merely examples, and the information required for processing control may be calculated using a method other than the method using the above-described mathematical formulas.

[0045] The present disclosure is not limited to the above-described embodiments, and includes modifications and improvements within the scope of achieving the object of the present disclosure.

[0046] In the above embodiment, the present disclosure is applied to a control device for a machine tool, but is not limited to this, and the present disclosure may also be applied to a display device for a machine tool.

[0047] 5 is a functional block diagram of the display device 9 of the machine tool according to the modified example. As shown in FIG. 5, the display device 9 of the machine tool includes a condition input unit 91, an air cut amount input unit 92, an information calculation unit 93, and a display unit 96.

[0048] The condition input unit 91 corresponds to the condition acquisition unit 11 in the above embodiment. That is, the condition input unit 91 accepts input of one or two pieces of information as preconditions out of three pieces of information: the oscillation phase difference between the nth thread cutting pass and a thread cutting pass after the nth thread cutting pass, information on the cutting amount in the radial direction of the workpiece, and information on the oscillation amplitude in the radial direction of the workpiece.

[0049] The air cut amount input unit 92 corresponds to the air cut amount acquisition unit 12 in the above embodiment. That is, the air cut amount input unit 92 receives input of a designated air cut amount that indicates the degree of air cut in the swing direction.

[0050] The information calculation unit 93 corresponds to a part of the machining control unit 13 in the above embodiment. That is, the information calculation unit 93 calculates, based on preconditions, the information among the three pieces of information that has not been accepted by the condition input unit so that the air cut amount based on the gap between the nth thread cutting pass and any thread cutting pass after the nth thread cutting pass becomes the designated air cut amount.

[0051] The display unit 96 corresponds to the display unit 16 in the above embodiment. That is, the display unit 96 displays the information calculated by the information calculation unit 93.

[0052] According to the display device 9 for a machine tool having the above-mentioned configuration, the same effects as those of the control device 1 for a machine tool according to the above-mentioned embodiment can be achieved. [Explanation of symbols]

[0053] 1. Machine tool control device 11 Condition acquisition section 12 Air cut amount acquisition unit 13 Processing control unit 16 Display section

Claims

1. A control device for a machine tool that performs thread cutting using a cutting tool that swings relative to a workpiece, a condition acquisition unit that acquires one or two pieces of information as preconditions out of three pieces of information: an oscillation phase difference between the n-th thread cutting pass and a thread cutting pass subsequent to the n-th thread cutting pass; information on the cutting depth in the radial direction of the workpiece; and information on the oscillation amplitude in the radial direction of the workpiece; an air cut amount acquisition unit that acquires a designated air cut amount that indicates the degree of air cut in the swing direction; and a machining control unit that determines, based on the preconditions, information that is not acquired by the condition acquisition unit among the three pieces of information, so that the air cut amount based on the gap between the n-th thread cutting pass and a thread cutting pass after the n-th thread cutting pass becomes the specified air cut amount, and performs machining control.

2. the condition acquisition unit acquires, as the precondition, information relating to the oscillation phase difference and the cutting-depth amount among the three pieces of information; 2. The control device for a machine tool according to claim 1, wherein the machining control unit determines information regarding the oscillation amplitude based on information regarding the oscillation phase difference and the depth of cut so that an air cut amount based on an interval between an n-th thread cutting machining pass and a thread cutting machining pass subsequent to the n-th thread cutting pass becomes the designated air cut amount.

3. The control device for a machine tool according to claim 1 or 2, further comprising a display unit that outputs information determined by the machining control unit.

4. A display device for a machine tool that performs thread cutting using a cutting tool that swings relative to a workpiece, a condition input unit that accepts input of one or two pieces of information as prerequisites out of three pieces of information: an oscillation phase difference between the n-th thread cutting pass and a thread cutting pass subsequent to the n-th thread cutting pass; information on the cutting depth in the radial direction of the workpiece; and information on the oscillation amplitude in the radial direction of the workpiece; an air cut amount input unit that receives an input of a designated air cut amount that indicates the degree of air cut in the swing direction; an information calculation unit that calculates, based on the preconditions, information that is not accepted by the condition input unit among the three pieces of information so that an air cut amount based on an interval between an n-th thread cutting pass and a thread cutting pass subsequent to the n-th thread cutting pass becomes the designated air cut amount; a display unit that displays the information calculated by the information calculation unit.

Images