Control device for machine tool and display device for machine tool

Abstract

The present invention provides a technique for reliably performing air cutting regardless of a swing phase difference during thread cutting swing machining. A control device (1) for a machine tool is provided with: a condition acquisition unit (11) that acquires, as a precondition, one or two of three pieces of information: a swing phase difference, information relating to the amount of insertion into a workpiece in the radial direction, and information relating to the swing amplitude of the workpiece in the radial direction; a null-cut amount acquisition unit (12) that acquires a specified null-cut amount indicating the degree of null-cut in the swing direction; and a machining control unit (13) that determines, from among the three pieces of information, information not acquired by the condition acquisition unit (11) on the basis of the preconditions, and performs machining control such that the amount of clearance between the nth thread cutting path and the thread cutting paths following the nth thread cutting path becomes a prescribed clearance amount.

Description

Technical Field

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

[0002] Conventionally, in order to prevent chips continuously generated during machining from being entangled in a workpiece, a cutting tool, etc. and causing machining defects, machine failures, etc., the workpiece is machined while the tool and the workpiece are relatively swung.

[0003] In such oscillating machining, there is known a technique in which a tool path as a tool trajectory is set to partially overlap with a previous tool path, thereby generating idle motion called air cutting in which the tool is separated from the surface of the workpiece to break up chips (for example, see Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6709163 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, in the oscillating process for turning, the phase difference changes according to the set frequency multiplier, but in the oscillating process for thread cutting, the phase difference between the previous path and the current path can be arbitrarily determined on the control device side. However, if the frequency of the previous path and the current path is different, each air cutting is not fixed, so considering efficiency, the oscillating phase difference is set to 180 degrees.

[0009] In the technology described in Patent Document 1, the swing amplitude is set based on the amount of idling, but like the prior art, it is assumed that the swing phase difference between the previous path and the current path is 180 degrees, so there is room for improvement in that idling is appropriately performed even when the swing phase difference is other than 180 degrees.

[0010] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a technology for reliably performing air cutting regardless of an oscillation phase difference in thread cutting oscillation processing.

[0011] Means for solving problems

[0012] The present invention discloses a control device for a machine tool, wherein the machine tool performs thread cutting processing by using a cutting tool that swings relative to a workpiece, and the control device comprises: a condition acquisition unit, which acquires one or two of three information, namely, a swing phase difference between an n-th thread cutting processing path and a thread cutting processing path after the n-th time, information related to a radial cutting amount into the workpiece, and information related to a swing amplitude of the workpiece in the radial direction, as a precondition; a hollow cutting amount acquisition unit, which acquires a designated hollow cutting amount indicating a degree of hollow cutting in a swinging direction; and a processing control unit, which determines information among the three information that is not acquired by the condition acquisition unit based on the precondition, and performs processing control so that the hollow cutting amount between the n-th thread cutting processing path and the thread cutting processing path after the n-th time becomes the designated hollow cutting amount.

[0013] In addition, the present disclosure is a display device for a machine tool, which performs thread cutting processing by using a cutting tool that swings relative to a workpiece, and the display device includes: a condition input unit, which accepts input of one or two of three information as preconditions: a swing phase difference between an n-th thread cutting processing path and a thread cutting processing path after the n-th time, information related to a radial cutting amount into the workpiece, and information related to a swing amplitude of the workpiece in the radial direction; an empty cutting amount input unit, which accepts input of a specified empty cutting amount indicating the degree of empty cutting in the swinging direction; an information calculation unit, which calculates information of the three information that is not accepted by the condition input unit based on the precondition so that the empty cutting amount based on the n-th thread cutting processing path and the thread cutting processing path after the n-th time becomes the specified empty cutting amount; and a display unit, which displays the information calculated by the information calculation unit.

[0014] Effects of the Invention

[0015] According to the present disclosure, it is possible to provide a technology capable of reliably performing air cutting regardless of the swing phase difference in thread cutting swing processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a functional block diagram of a control device for a machine tool according to one embodiment of the present invention.

[0017] Figure 2 This is a block diagram showing conditions acquired by the condition acquisition unit of this embodiment.

[0018] Figure 3 This is a diagram showing an example of a machining program.

[0019] Figure 4 This is a diagram showing the positional relationship between the workpiece and the cutting tool.

[0020] Figure 5This is a functional block diagram of a display device for a machine tool according to a modified example. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0022] Figure 1 1 is a functional block diagram of a control device 1 for a machine tool according to an embodiment of the present invention. The control device 1 for a machine tool according to an embodiment of the present invention is used to perform a thread cutting process by a cutting tool that swings relative to a workpiece in a radial direction. Figure 1 For convenience, only the motor 3 driving one feed axis is shown. In addition, in the cutting process of this embodiment, the shape of the workpiece is not limited. That is, even if the workpiece has a tapered portion or an arc-shaped portion on the processing surface and multiple feed axes (Z axis and X axis) are required, even if the workpiece is cylindrical or cylindrical and a specific feed axis (Z axis) is sufficient, it can also be applied.

[0023] The control device 1 of the machine tool of the present embodiment is constituted by, for example, a computer having a memory such as a ROM (readonly memory), a RAM (random access memory), a CPU (central processing unit), and a communication control unit connected to each other via a bus. The functions and actions of the above-mentioned functional units are realized by the cooperation of the CPU, the memory, and the control program stored in the memory mounted on the above-mentioned computer. In addition, the control device 1 of the machine tool can be constituted by a CNC (Computer Numerical Controller), a PLC (Programmable Logic Controller), etc., and can also be connected to a higher-level computer that outputs processing conditions such as rotation speed in addition to the processing program.

[0024] like Figure 1 As shown, the control device 1 of the machine tool includes a condition acquisition unit 11 , an empty cut amount acquisition unit 12 , a machining control unit 13 , a storage unit 14 , an input unit 15 , and a display unit 16 .

[0025] The condition acquisition unit 11 acquires machining conditions and swing conditions for swing machining a workpiece. The machining conditions and swing conditions may be stored in the storage unit 14 or may be output from an external computer.

[0026] Here, the processing conditions include, in addition to at least information on the feed amount per relative rotation of the cutting tool and the workpiece and information on the shape of the cutting edge of the cutting tool, information on, for example, the spindle rotation speed S (1 / min), the feed speed of the cutting tool (mm / min), the workpiece diameter (mm), the back angle of the cutting tool (°), etc. In addition, as information on the feed amount per relative rotation of the cutting tool and the workpiece, a combination of the feed amount per revolution F (mm / rev), the spindle rotation speed S (1 / min) and the feed speed of the cutting tool (mm / min) can be cited, and as information on the shape of the cutting edge of the cutting tool, R (mm) of the cutting edge can be cited.

[0027] In addition, as the oscillation condition, information related to the radial oscillation number of the workpiece and information related to the radial oscillation amplitude of the workpiece are included. As the information related to the radial oscillation number of the workpiece, an oscillation frequency magnification I (times) indicating the oscillation frequency per one rotation of the spindle can be cited. In addition, as the information related to the radial oscillation amplitude of the workpiece relative to the cutting tool and the workpiece, an oscillation amplitude magnification K (times) indicating the size of the oscillation amplitude relative to the radial penetration amount of the workpiece in the thread cutting process can be cited.

[0028] The empty cut amount acquisition unit 12 acquires a designated empty cut amount designated in advance by an operator, etc. The empty cut amount may be stored in the storage unit 14 , acquired from an external computer, or input through the input unit 15 , for example.

[0029] The amount of empty cutting mentioned here is the amount of empty cutting between the nth thread cutting processing path and the thread cutting processing path after the nth (after n+1). In this embodiment, the amount of empty cutting between the nth thread cutting processing path and the n+1th thread cutting processing path is used to determine the processing conditions. In addition, the amount of empty cutting between the nth thread cutting processing path and the n+2th thread cutting processing path can also be used to determine the processing conditions.

[0030] The amount of cut in this embodiment uses the distance in the swing direction. In this embodiment, since the workpiece is swung in the radial direction, the amount of cut becomes a numerical value indicating the degree of cut in the radial direction of the workpiece. The amount of cut can be any index indicating the size of the cut, and can be the distance in the swing direction, or can be expressed by an area including the swing direction, or a level related to the amount of cut determined in advance in a table, or a ratio relative to an arbitrary reference value (such as the amount of cut-in, etc.).

[0031] The processing control unit 13 performs processing control so that the amount of cut after the start of processing becomes a designated amount of cut based on the conditions acquired by the condition acquisition unit 11. The processing control performed by the processing control unit 13 will be described in detail later.

[0032] The storage unit 14 stores various information used for controlling and processing the machine tool. In the present embodiment, the storage unit 14 stores processing conditions, swing conditions, and the amount of air cutting specified by the operator. The processing conditions, swing conditions, and the amount of air cutting are, for example, parameters input into the processing program by the operator or parameters specified as machine tools. In addition, the storage unit 14 may be configured not inside the control device 1 but outside.

[0033] The input unit 15 inputs processing-related information according to the operator's input operation on an input unit (not shown) such as a keyboard or a touch panel. The processing-related information input through the input unit 15 is stored in the storage unit 14 or other units of the control device 1.

[0034] The display unit 16 displays various information related to the machine tool, the control device 1 , and processing.

[0035] Next, refer to Figure 2 The conditions acquired by the condition acquisition unit 11 and the process control by the process control unit 13 will be described. Figure 2 This is a block diagram showing conditions acquired by the condition acquisition unit 11 of this embodiment.

[0036] like Figure 2 As shown, the condition acquisition unit 11 includes a phase difference acquisition unit 21 and a cutting amount acquisition unit 22. The phase difference acquisition unit 21 acquires the swing phase difference set in the control device 1 of the machine tool as a condition for thread cutting. The cutting amount acquisition unit 22 acquires the cutting amount of thread cutting as a condition for thread cutting.

[0037] Next, a control example of the control device 1 according to the present embodiment will be described. Figure 4 : is a graph showing the positional relationship between the workpiece and the cutting tool T. Figure 3 The machining program shown is obtained by the operator designating various information via the input unit 15 or the like.

[0038] exist Figure 4 The positional relationship between the workpiece and the cutting tool T is shown in the diagram of FIG. The machining control unit 13 determines the swing amplitude so that the amount of empty cutting between the nth cutting path, i.e., the previous path, and the n+1th cutting path, i.e., the current path, becomes the specified amount of empty cutting. The swing amplitude is in the same direction as the X-axis direction, which is also the cutting direction of the workpiece.

[0039] Figure 3The "S1000 M03" block in the machining program indicates that the spindle is rotated forward. The "L0.02" block indicating the designated air cutting amount is described in the "G8.5P3L0.02" block. The cutting amount can be obtained from the difference in the X coordinates by the "G92 X10.0Z10.00 F2.0" block and the "G92 X9.7 Z10.00 F2.0" block.

[0040] When the machining operation starts, the condition acquisition unit 11 of the control device 1 acquires the swing phase difference held as a setting of the machine tool control device 1. In this example, a phase difference of 90 degrees is set in the control device 1. The condition acquisition unit 11 acquires the swing phase difference of 90 degrees.

[0041] In addition, the condition acquisition unit 11 acquires the cutting depth from the machining program. Figure 3 In the example, 10.0-9.7=0.3 [mm] is calculated based on "X10.0" and "X9.7" and obtained as the cutting amount. In addition, the empty cutting amount acquisition unit 12 acquires the designated empty cutting amount. Figure 3 In the example, the air cutting amount acquisition unit 12 acquires the designated air cutting amount 0.02 [mm] from "L0.02".

[0042] The machining control unit 13 determines the oscillation amplitude for thread cutting by using the following formula based on the oscillation phase difference and the cutting depth as the conditions acquired by the condition acquisition unit 11 and the designated air cutting amount acquired by the air cutting amount acquisition unit 12. In this example, the phase angle 90 [°], the cutting depth 0.3 [mm], and the designated air cutting amount = 0.02 [mm] are substituted.

[0043] [Formula 1]

[0044]

[0045] In the formula (1), I represents the frequency magnification [times], L represents the specified air cutting amount [mm], A represents the swing amplitude [mm], and θ represents the phase of the workpiece with the air cutting amount L [°].

[0046] The processing control unit 13 outputs information indicating the calculated swing amplitude to the display unit 16. The display unit 16 conveys the swing amplitude to the operator through text information indicating the swing amplitude, graphic information, or a combination thereof.

[0047] According to the control device 1 of the machine tool for performing thread cutting using the cutting tool T that swings relative to the workpiece according to the present embodiment described above, the following effects are achieved.

[0048] The control device 1 of the machine tool of the present embodiment comprises: a condition acquisition unit 11, which acquires one or two of three pieces of information, namely, the swing phase difference between the n-th thread cutting process path and the thread cutting process path after the n-th time, information related to the radial cutting amount into the workpiece, and information related to the swing amplitude of the workpiece in the radial direction, as a precondition; a hollow cutting amount acquisition unit 12, which acquires a designated hollow cutting amount indicating the degree of hollow cutting in the swing direction; and a processing control unit 13, which determines the information not acquired by the condition acquisition unit 11 among the three pieces of information according to the precondition, and performs processing control so that the hollow cutting amount between the n-th thread cutting process path and the thread cutting process path after the n-th time becomes the designated hollow cutting amount. Thus, since the designated hollow cutting amount as the target is set, it is possible to accurately determine whether the chips can be cut even if the processing conditions change during the thread cutting process. In addition, by specifying the margin using the designated hollow cutting amount, appropriate idle rotation can be achieved even if the swing phase difference is not 180 degrees.

[0049] The condition acquisition unit 11 of this embodiment acquires the swing phase difference and the information related to the cutting amount among the three pieces of information as a precondition, and the processing control unit 13 determines the information related to the swing amplitude based on the swing phase difference and the information related to the cutting amount so that the clearance amount between the n-th thread cutting processing path and the n-th and subsequent thread cutting processing paths becomes the designated clearance amount. Thus, even if the swing phase difference is not 180 degrees, the swing amplitude corresponding to the designated clearance amount can be accurately calculated.

[0050] The control device 1 of this embodiment further includes a display unit 16 that outputs information determined by the process control unit 13. This allows the operator to easily check safety and production plans based on calculation results of the process control unit 13 such as the swing amplitude.

[0051] In the above embodiment, the machining control unit 13 calculates the swing amplitude, but the amplitude magnification may be determined instead of the swing amplitude. In this case, the amplitude is determined according to the radial penetration amount of the workpiece in the thread cutting machining and the amplitude magnification during the control stage, and the control is performed with the amplitude.

[0052] In addition, the processing control unit may also be configured to determine information different from the information about the swing amplitude based on the conditions obtained by the condition acquisition unit. For example, the condition acquisition unit may acquire the swing phase difference and information about the swing amplitude, and the processing control unit may determine the information about the cut-in amount based on the swing phase difference and the information about the swing amplitude. In addition, the condition acquisition unit may acquire the swing phase difference, information about the cut-in amount, and determination information for determining the information about the swing amplitude, and the processing control unit may determine the information about the cut-in amount and the information about the swing amplitude based on the swing phase difference and the determination information. In addition, the condition acquisition unit may acquire information about the swing amplitude, information about the cut-in amount, and determination information for determining the swing phase difference, and the processing control unit may determine the information about the cut-in amount and the swing phase difference based on the information about the swing amplitude and the determination information. The calculation of specific numerical values ​​may also be performed using formula (1), for example.

[0053] In addition, the above-mentioned determination information may include, for example, the upper limit value of the specified swing amplitude, the upper limit value of the speed, the upper limit value of the acceleration, the upper limit value of the jerk, etc. Based on this information and the swing frequency, the swing amplitude can be uniquely determined. In addition, even if the determination information is set as a recommended value of the swing phase difference and the setting is set to operate at the recommended value, the swing phase difference can be uniquely determined. In addition, if the determination information is set as the upper limit value of the radial penetration amount into the workpiece, and the radial penetration amount into the workpiece is set to be the upper limit value, the radial penetration amount into the workpiece can be uniquely determined. Moreover, multiple of these exemplified determination information can also be combined. In this way, the determination information is a rule set for the machine tool, as long as it is information that the processing control unit 13 can determine the information.

[0054] The above-mentioned determination method and calculation method are merely examples, and the information required for machining control may be calculated by a method different from the method using the above-mentioned mathematical formula.

[0055] In addition, the present disclosure is not limited to the above-mentioned embodiments, and modifications and improvements within the scope that can achieve the purpose of the present disclosure are included in the present disclosure.

[0056] In the above-mentioned embodiment, the present disclosure is applied to a control device of a machine tool, but the present disclosure is not limited thereto. The present disclosure may also be applied to a display device of a machine tool.

[0057] Here, Figure 5 FIG. 9 is a functional block diagram of a display device 9 of a machine tool according to a modified example. Figure 5 As shown, 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 .

[0058] The condition input unit 91 is equivalent to the condition acquisition unit 11 of the above-mentioned embodiment. That is, the condition input unit 91 receives input of one or two of the three pieces of information as prerequisites: the oscillation phase difference between the n-th thread cutting process path and the thread cutting process paths after the n-th time, the information on the radial penetration amount into the workpiece, and the information on the oscillation amplitude of the workpiece in the radial direction.

[0059] The hollow cutting amount input unit 92 corresponds to the hollow cutting amount acquisition unit 12 of the above-mentioned embodiment. That is, the hollow cutting amount input unit 92 receives input of a designated hollow cutting amount indicating the degree of hollow cutting in the swing direction.

[0060] The information calculation unit 93 is equivalent to a part of the processing control unit 13 of the above-mentioned embodiment. That is, the information calculation unit 93 calculates the information not received by the condition input unit among the three information based on the precondition so that the empty cutting amount between the n-th thread cutting processing path and the n-th and subsequent thread cutting processing paths becomes the specified empty cutting amount.

[0061] The display unit 96 corresponds to the display unit 16 of the above-described embodiment. That is, the display unit 96 displays the information calculated by the information calculation unit 93.

[0062] According to the display device 9 for a machine tool having the above-described configuration, the same effects as those of the control device 1 for a machine tool according to the above-described embodiment are achieved.

[0063] Description of Reference Numerals

[0064] 1Machine tool control device

[0065] 11 Condition Acquisition Department

[0066] 12 Empty cutting amount acquisition unit

[0067] 13Processing Control Department

[0068] 16 display unit.

Claims

1. A control device for a machine tool, wherein the machine tool performs thread cutting processing by means of a cutting tool that swings relative to a workpiece, characterized in that: The control device has: a condition acquisition unit that acquires, as a precondition, one or two of three pieces of information: a swing phase difference between an n-th thread cutting process path and a thread cutting process path after the n-th time, information on a radial penetration amount into a workpiece, and information on a swing amplitude of the workpiece in a radial direction; a hollow cutting amount acquisition unit that acquires a designated hollow cutting amount indicating a degree of hollow cutting in a swinging direction; and A machining control unit determines information not acquired by the condition acquisition unit among three pieces of information based on the precondition, and performs machining control so that the clearance amount between the nth thread cutting machining path and the nth and subsequent thread cutting machining paths becomes the designated clearance amount.

2. The control device for a machine tool according to claim 1, characterized in that: The condition acquisition unit acquires the swing phase difference and the information related to the cut-in amount among three pieces of information as the precondition, The machining control unit determines the information on the oscillation amplitude based on the oscillation phase difference and the information on the cutting amount so that the clearance amount between the nth thread cutting machining path and the nth and subsequent thread cutting machining paths becomes the designated clearance amount.

3. The control device for a machine tool according to claim 1 or 2, characterized in that: The control device further includes a display unit that outputs information determined by the process control unit.

4. A display device for a machine tool, wherein the machine tool performs thread cutting processing by means of a cutting tool that swings relative to a workpiece, characterized in that: The display device comprises: a condition input unit that receives input of one or two of three pieces of information as preconditions: a swing phase difference between an n-th thread cutting process path and a thread cutting process path after the n-th thread cutting process path, information on a radial penetration amount into a workpiece, and information on a swing amplitude of the workpiece in a radial direction; an air cutting amount input unit for receiving an input of a designated air cutting amount indicating the degree of air cutting in the swing direction; an information calculation unit that calculates information of the three information that is not received by the condition input unit based on the precondition so that the clearance amount between the n-th thread cutting process path and the n-th and subsequent thread cutting process paths becomes the designated clearance amount; and A display unit displays the information calculated by the information calculation unit.

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