Numerical control device and numerical control method for controlling movement of machining tools by fixed cycle

Abstract

The numerical control device (100) of the present invention for controlling the movement of a machining tool (T) through a fixed cycle comprises: a main control unit (110) which issues machining instructions to a machining device (10) based on a machining program; a machining program analysis unit (120) which pre-reads and analyzes the machining program; a machining state measurement unit (130) which measures a physical quantity representing a machining state during machining; and a start position determination unit (140) which determines an overlapping control start position (Po) based on the measured physical quantity. The main control unit (110) executes overlapping control when it is determined that the machining tool (T) has reached the overlapping control start position (Po).

Description

Technical Field

[0001] The present invention relates to a numerical control device and a numerical control method for controlling the movement of a machining tool through a fixed cycle. Background Art

[0002] In machining of a workpiece, when the workpiece is repeatedly machined by a machining tool, numerical control based on a fixed cycle is known. As machining performed by such a fixed cycle, for example, drilling, boring, and tapping are known.

[0003] In such a fixed cycle-based numerical control, when machining of one machining position (such as a hole, etc.) is completed, movement control for moving the machining tool from the machining position to the next machining position is also included in the machining program. In such a machining tool movement control, the movement command for the drive axis of the moving mechanism of the machining tool is usually executed separately, while in contrast, "overlap control" in which the movement commands for multiple drive axes are repeated is sometimes executed.

[0004] As an example of such overlapping control, a high-speed hole-punching method (hole-punching method) is disclosed in patent document 1. In the hole-punching method for punching multiple holes on a workpiece using a machine tool controlled by a numerical control device, a hole bottom in-position width for detecting that the tool has reached the commanded hole bottom position in the hole-punching cycle, a positioning in-position width for detecting that the tool mounting axis has been positioned at the commanded hole-punching position, and a retraction in-position width for detecting that the tool mounting axis has reached the commanded position when it is retracted for recovery are respectively set. At least one of the positioning in-position width and the retraction in-position width is set to be larger than the hole bottom in-position width. When generating the execution form data of each block of the NC program, for the positioning block and the retraction block, data for identifying each block is added to the execution form data. When the pulse distribution based on the execution form data ends, it is determined whether the tool has reached each in-position width based on the data identifying the positioning, hole-punching, and retraction, and the next block is started to be executed by reaching each in-position width. According to this aspect, the next pulse distribution can be executed without waiting for the completion of the tool movement in each axial direction, so that the waiting time for starting the pulse distribution can be shortened, thereby speeding up the drilling operation.

[0005] In addition, Patent Document 2 discloses a numerical control device that starts the allocation of the movement instructions of a block of movement instructions instructed by a machining program at the start timing of the next block specified according to the overlap instruction, and the start timing of the next block specified is when the remaining movement instruction amount in the movement instruction allocation becomes less than the set amount. According to this numerical control device, the allocation of the movement instructions of the next block is started during the allocation of the movement instructions of a block in the machining program, so that the execution time of the machining program is shortened, and the overlap processing can be performed only in the required parts and intervals according to the overlap instruction.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 64-27838

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 11-39017 Summary of the invention

[0010] Problems to be solved by the invention

[0011] In the above-mentioned conventional numerical control device and numerical control method, the overlapping control when moving to the next processing position after the processing of one processing position is completed needs to record its instructions in advance in the processing program including the control start position. For example, in Patent Document 1, it is necessary to predefine each in-position width in the processing program, and in Patent Document 2, it is necessary to predefine the remaining movement instruction amount for determining the start timing of the next block.

[0012] Thus, pre-recording the start position of the overlap control in the machining program becomes an additional research item and a burden for the program generator. In particular, when machining based on multiple fixed cycles is performed, it is necessary to set the overlap start position for each fixed cycle separately, which further increases the burden.

[0013] For such reasons, there is a demand for a numerical control device and a numerical control method that can automatically determine an overlap start position from a machining program based on a fixed cycle.

[0014] Means for solving problems

[0015] A numerical control device for controlling the movement of a machining tool through a fixed cycle according to one embodiment of the present invention comprises: a main control unit, which issues machining instructions to a machining device based on a machining program; a machining program analysis unit, which pre-reads and analyzes the machining program; a machining state measuring unit, which measures a physical quantity representing a machining state during machining; and a start position determination unit, which determines an overlapping control start position based on the physical quantity, wherein the main control unit executes overlapping control of the machining tool when it is determined that the machining tool has reached the overlapping control start position.

[0016] In addition, a numerical control method for controlling the movement of a machining tool through a fixed cycle according to one embodiment of the present invention includes the following steps when pre-reading a machining program and issuing a machining instruction to a machining device: a step of measuring a physical quantity representing a machining state during machining; a step of determining a starting position for overlapping control based on the physical quantity; and a step of executing overlapping control of the machining tool when it is determined that the machining tool has reached the starting position for overlapping control.

[0017] Effects of the Invention

[0018] According to one embodiment of the present invention, a physical quantity representing a machining state during machining is measured, and an overlapping control start position is determined based on the physical quantity. When it is determined that the machining tool has reached the overlapping control start position, overlapping control of the machining tool is performed, thereby being able to automatically determine the overlapping start position from a machining program based on a fixed cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a block diagram showing the relationship between a numerical controller for controlling the movement of a machining tool by a fixed cycle and its peripheral devices according to a first embodiment as a representative example of the present invention.

[0020] Figure 2 This is a partial cross-sectional view showing an example of movement control of a machining tool by a fixed cycle according to the first embodiment.

[0021] Figure 3A This is a graph showing an example of physical quantities measured in the first embodiment.

[0022] Figure 3B This is a graph showing an example of physical quantities measured in the first embodiment.

[0023] Figure 4 This is a flowchart showing the operation of the numerical control method according to the first embodiment of the present invention.

[0024] Figure 5 This is a flowchart showing the operation of the numerical control method according to the modified example of the first embodiment.

[0025] Figure 6 This is a graph showing an example of physical quantities measured in the numerical control device according to the second embodiment of the present invention.

[0026] Figure 7 It is a partial cross-sectional view showing an example of movement control of a machining tool by a fixed cycle according to the third embodiment. DETAILED DESCRIPTION

[0027] The following, with the attached Figure 1 An embodiment of a numerical control device and a numerical control method for controlling the movement of a machining tool by a fixed cycle, which is a representative example of the present invention, will be described below.

[0028] <First embodiment>

[0029] Figure 1 1 is a block diagram showing the relationship between a numerical control device for controlling the movement of a machining tool by a fixed cycle and its peripheral devices according to a first embodiment of the present invention as a representative example. Figure 1 As shown, as an example, the numerical control device 100 of the first embodiment includes: a main control unit 110, which issues a processing instruction to a processing device according to a processing program; a processing program analysis unit 120, which pre-reads and analyzes the processing program; a processing state measurement unit 130, which measures a physical quantity representing a processing state during processing; and a start position determination unit 140, which determines a start position of overlapping control based on the measured physical quantity.

[0030] The numerical controller 100 is connected to the processing device 10 that performs processing based on a fixed cycle or the external storage device 20 via a wired or communication line so as to be able to communicate with each other, and issues various control commands to the processing device 10 via the main control unit 110, and receives detection signals detected by various sensors (such as the acoustic sensor 14 and the load sensor 16) installed in the processing device 10. In addition, the numerical controller 100 takes in a processing program that describes the control operation of the processing device 10 from the external storage device 20, and updates the processing program as needed.

[0031] The processing device 10 is configured to be a device capable of continuously performing a fixed cycle-based drilling process, a boring process, a tapping process, etc. on a workpiece W. The processing device 10 is provided with a processing control unit 12 that controls the operation of the entire device including a driving unit (not shown), wherein the driving unit is used to drive a processing tool (see Figure 2and various sensors (e.g., an acoustic sensor 14 and a load sensor 16) that detect physical quantities indicating the machining state of the workpiece W. Here, as the acoustic sensor 14 and the load sensor 16, a microphone that acquires sound data near the workpiece W of the machining device 10, a torque sensor that measures the torque of a spindle that rotates the machining tool T, and the like can be exemplified.

[0032] The main control unit 110 is a unit that issues an operation command signal to the processing device 10, and generates a command signal for the processing device based on the program block of the processing program pre-read by the processing program analysis unit 120, the information of the overlap control start position determined by the start position determination unit 140 described later, etc. In addition, the main control unit 110 may also have a function of obtaining data of physical quantities representing various processing states from the processing state measurement unit 130, and determining the operation state of the processing device 10 based on the physical quantities.

[0033] As an example, the processing program analysis unit 120 includes: a function of determining what control instructions are included in the pre-read processing program blocks by pre-reading the processing program blocks from the external storage device 20 one by one and analyzing them; and a function of temporarily storing and saving the pre-read processing program blocks. Then, the processing program analysis unit 120 sends the pre-read processing program blocks to the main control unit 110 for the normal processing routine of the pre-read processing program blocks, and sends the pre-read processing program blocks to the main control unit 110 and the start position determination unit 140 described later when the pre-read processing program blocks include the overlap control subroutine. In addition, the processing program analysis unit 120 may also include the following functions: by connecting to the external storage device 20, not only the processing program is read, but also the processing program is added or modified based on the processing results from the main control unit 110.

[0034] As an example, the machining state measuring unit 130 is connected to various sensors (e.g., the acoustic sensor 14 and the load sensor 16) of the machining device 10, and receives detection signals from these sensors at each predetermined control clock. In addition, the received physical quantities (e.g., acoustic data or load data of the machining tool T) from the various sensors are sent in real time to the main control unit 110 that generates and sends control instructions and determines the overlap control start position (see Figure 2 The starting position determination unit 140 is denoted by the reference numeral Po).

[0035] The start position determination unit 140 determines the overlap control start position Po for starting the overlap control based on the real-time physical quantities from various sensors measured by the machining state measurement unit 130. Then, the overlap control start position Po determined by the start position determination unit 140 is sent to the main control unit 110. The main control unit 110, which receives the overlap control start position Po, sends a command signal for executing the overlap control of the machining tool when it is determined that the position of the machining tool T has reached the overlap control start position Po.

[0036] Figure 2 This is a partial cross-sectional view showing an example of movement control of a machining tool by a fixed cycle according to the first embodiment. Here, as a typical machining by a fixed cycle, a case of performing drilling machining to continuously form a plurality of holes H1 and H2 in a workpiece W is exemplified.

[0037] like Figure 2 As shown, in the machining control of the first embodiment, the machining tool T is first moved to the machining start position Ps of the hole H1 on the workpiece W. At this time, the machining tool T may be in a rotating state in advance, or may be rotated at the machining start position Ps.

[0038] Next, the machining tool T is moved to the reference position Pr while rotating, and after temporarily stopping at the reference position Pr, it cuts into the workpiece W in the Z direction. At this time, the machining tool T contacts the workpiece W at the first contact position Pp with the surface of the workpiece W, and machining starts.

[0039] Next, the rotating machining tool T cuts into the hole bottom position Pz at a predetermined depth D. At this time, the cutting from the contact position Pp to the hole bottom position Pz may be performed multiple times in consideration of the load applied to the machining tool T, but the case of cutting into the hole bottom position Pz in one operation is exemplified here.

[0040] The processing tool T that has completed the drilling process to the hole bottom position Pz returns in a fast forward manner in the Z direction while rotating to the overlap control start position Po assumed to be at the same height as the surface of the workpiece W. In the first embodiment of the present invention, when it is determined that the processing tool T that has returned from the hole bottom position Pz has reached the overlap control start position Po, the movement of the processing tool T is controlled by overlapping control in which the feed of the processing tool T in the Z direction overlaps the feed in the X direction.

[0041] That is, Figure 2As shown, under normal circumstances, the machining tool T that returns from the hole bottom position Pz quickly moves to the return position Pe' through the Z-direction path Rz, and then fast-forwards through the X-direction path Rx to move to the machining start position Ps' of the next hole H2. In contrast, in overlapping control, the machining tool T that returns from the hole bottom position Pz quickly switches to overlapping control when it is determined to have returned to the overlapping control start position Po, and fast-forwards through the overlapping path Ro to move to the machining start position Ps' of the next hole H2. In addition, in Figure 2 In FIG. 1 , overlapping control in two dimensions is described as a cross-sectional view, but the movement control may be performed by overlapping movements in the XYZ directions.

[0042] Figure 3A as well as Figure 3B is a graph showing an example of a physical quantity measured in the first embodiment. Figure 1 The situation of the sound data measured by the acoustic sensor 14 of the processing device 10 is shown.

[0043] like Figure 3A As shown, in the fixed cycle machining control of the first embodiment, the sound data WD1 shifts between a first amplitude level A1 during a period when the machining tool T moves without contacting the workpiece W, a second amplitude level A2 during a period when the machining tool T contacts and cuts into the workpiece W, and a third amplitude level A3 during a period when the machining tool T returns from the bottom position Pz of the hole to the overlapping control start position Po.

[0044] That is, in Figure 2 In the section from the machining start position Ps to the contact position Pp via the reference position Pr, the sound data WD1 is shifted at the first amplitude level A1, and changes to the second amplitude level A2 when the machining tool T contacts the workpiece W at the contact position Pp (i.e., time Tp) and starts cutting in. Next, in the cutting section to the hole bottom position Pz, the sound data WD1 is shifted at the second amplitude level A2, and changes to the third amplitude level A3 when the machining tool T switches to the tool being pulled out and returns after reaching the hole bottom position Pz.

[0045] Next, in the tool return interval from the hole bottom position Pz to the overlap control start position Po (i.e., time To), the sound data WD1 is shifted at the third amplitude level A3, and when the front end of the machining tool T is pulled out from the workpiece W, the sound data WD1 returns to the first amplitude level A1. After that, since there is no contact between the machining tool T and the workpiece W, in the interval from the overlap control start position Po to the next machining start position Ps', the sound data WD1 is shifted at the first amplitude level A1.

[0046] According to the above, in the first embodiment, the sound data WD1 is measured as a physical quantity during machining, and if the timing of switching from the third amplitude level A3 to the first amplitude level A1 can be determined, the overlap control start position Po for directly switching to the overlap control during the machining of the fixed cycle can be detected. That is, the numerical control device of the first embodiment of the present invention operates in the following manner: the sound data WD1 is measured as a physical quantity indicating the machining state during machining, the overlap control start position Po is determined based on the sound data WD1, and when it is determined that the machining tool T has reached the overlap control start position Po, the overlap control is executed.

[0047] Here, regarding the sound data WD1 as a physical quantity indicating the machining state illustrated above, as an example, sound is collected by the acoustic sensor 14 such as a microphone, so data containing a lot of noise may be obtained depending on where the acoustic sensor 14 is arranged in the machining device 10. In such a case, as shown below, the following method can be illustrated: frequency analysis is performed on the measured sound data WD1 to extract a representative value of the frequency component generated by the contact between the machining tool T and the workpiece W.

[0048] For example, Figure 3B As shown, the spectrum of each frequency is extracted to represent Figure 3A The frequency analysis data of the sound data WD1 at the reference position Pr, contact position Pp and overlap control start position Po are shown. Based on the frequency analysis data, for example, when the spectrum intensity at a specific frequency K1 exceeds the first threshold V1, it can be determined that the machining tool T is in contact with the workpiece W.

[0049] In addition, as another example, as shown in the frequency analysis data of the contact position Pp, when several low-frequency components around the frequency K1 exceed the second threshold, it is possible to determine whether the machining tool T is in the cutting action or in the tool return action. That is, by setting multiple spectrum intensity thresholds, the current machining position can be estimated.

[0050] Figure 4 1 is a flowchart showing the operation of the numerical control method according to the first embodiment of the present invention. Figure 4 As shown, the machining program analyzing unit 120 of the numerical controller 100 first pre-reads a program block of the machining program from the external storage device 20 (step S10 ).

[0051] Next, the processing program analysis unit 120 analyzes what kind of action or instruction the pre-read processing program block contains (step S11). At this time, the pre-read program block is temporarily accumulated in the processing program analysis unit 120, and as described above, it is sent to the main control unit 110 and the start position determination unit 140 for each action instruction.

[0052] Next, the main control unit 110 issues a command for executing a machining operation based on a fixed cycle based on the program block analyzed in step S11 (step S12). Then, during the execution of normal machining, the main control unit 110 obtains a physical quantity (sound data WD1) representing the machining state via the machining state measuring unit 130 (step S13).

[0053] Next, the main control unit 110 determines whether the current position of the machining tool T is the overlap control start position Po based on the physical quantity acquired in step S13 (step S14). As an example, the method described using FIG. 3 can be used as a determination method at this time.

[0054] In step S14, if it is determined that the current position of the machining tool T has not reached the overlap control start position Po, the process returns to step S10 and the operation starting from step S10 is repeated. On the other hand, if it is determined that the current position of the machining tool T has reached the overlap control start position Po, the process proceeds to step SS and transfers to the overlap control subroutine.

[0055] As an example, the "overlap control subroutine" shown as step SS is Figure 2 The movement control of the processing tool T shown is to overlap the feed in the Z direction and the feed in the X direction of the processing tool T. Such an "overlap control subroutine" can apply a conventionally known method, and therefore the description thereof is omitted here.

[0056] Figure 5 FIG. 1 is a flowchart showing the operation of the numerical control method according to the modified example of the first embodiment. Figure 5 As shown, the machining program analysis unit 120 of the numerical control device 100 and Figure 4 The same is true for the case of . The program blocks of the machining program are pre-read from the external storage device 20 (step S20).

[0057] Next, the machining program analyzing unit 120 analyzes what kind of actions or instructions the pre-read machining program block contains (step S21). Next, the main control unit 110 issues a command for executing a machining action based on a fixed cycle based on the program block analyzed in step S21 (step S22).

[0058] Next, during the normal machining process, the main control unit 110 obtains the physical quantity (sound data WD1) indicating the machining state via the machining state measuring unit 130 (step S23), and determines whether the machining tool T is in initial contact with the workpiece W (i.e., whether the contact is reached). Figure 2 contact position Pp shown) (step S24).

[0059] As an example of the determination method at this time, we can cite Figure 3A The method of detecting the moment when the contact position Pp that first contacts the workpiece becomes the second amplitude level A2 in the sound data WD1 shown in the figure, etc. In addition, the above-mentioned Figure 3B Whether or not it is the contact position Pp is determined by the frequency analysis shown.

[0060] In step S24, when it is determined that the machining tool T is not in contact with the workpiece W initially, the process returns to step S20 and the operations starting from step S20 are repeated. On the other hand, when it is determined that the machining tool T is in contact with the workpiece W, the process proceeds to step S25.

[0061] Next, the start position determination unit 140 determines the overlap control start position Po, which is a judgment index for switching to the overlap control later, through calculation, and sends information on the determined overlap control start position Po to the main control unit 110 (step S25). At this time, as a method for determining the overlap control start position Po, for example, since the distance (depth) D from the surface of the workpiece W to the hole bottom position Pz is determined as the control value, it can be calculated as "Po = Pp + 2D" as the cumulative distance.

[0062] Next, the main control unit 110 issues a command to continue the machining operation based on the current program block (step S26), and then obtains the current position of the machining tool T in the machining control state (step S27). Then, the main control unit 110 determines whether the obtained current position is consistent with the overlap control start position Po calculated in step S25 (step S28).

[0063] In step S28, if it is determined that the current position of the machining tool T is not consistent with the overlap control start position Po, the process returns to step S26 and the operation starting from step S26 is repeated. On the other hand, if it is determined that the current position of the machining tool T is consistent with the overlap control start position Po, the process proceeds to step SS and transfers to the overlap control subroutine. Figure 4 In the same way, after executing the overlap control subroutine, the process ends.

[0064] As described above, the numerical control device and the numerical control method of the first embodiment of the present invention are configured to measure a physical quantity representing a machining state during machining, determine an overlapping control start position based on the physical quantity, and execute overlapping control of the machining tool when it is determined that the machining tool has reached the above-mentioned overlapping control start position, thereby being able to automatically determine the overlapping start position from a machining program based on a fixed cycle.

[0065] In the first embodiment, the case where the sound data WD1 is obtained using the acoustic sensor 14 is exemplified, but as the same data, for example, the case where the vibration data is obtained by installing a vibration sensor on the processing device 10 may be adopted. In this case, it can be directly installed on the structural element of the processing device 10, so that data with less noise can be obtained.

[0066] <Second embodiment>

[0067] Figure 6 is a graph showing an example of physical quantities measured in a numerical control device according to a second embodiment of the present invention. Figure 1 to Figure 5 In the block diagrams, flow charts, and the like shown in the drawings, components having the same or common configurations as those in the first embodiment are denoted by the same reference numerals, and their repeated descriptions are omitted.

[0068] In the fixed cycle machining control of the second embodiment, a physical quantity indicating the state of the machining tool T during machining is directly acquired instead of the sound data WD1 measured by the acoustic sensor 14. As such a physical quantity, as an example, the torque during machining measured by a torque sensor provided on a spindle for rotating the machining tool T is used as the load data WD2.

[0069] like Figure 6 As shown, the load data WD2 shifts between a first amplitude level A1 during the period when the processing tool T moves without contacting the workpiece W, a second amplitude level A2 which is the load at the contact position Pp (i.e., time Tp) at the moment when the processing tool T contacts and cuts into the workpiece W, a third amplitude level A3 which is the load at the bottom hole position Pz where the processing tool T cuts deepest into the workpiece W, and a fourth amplitude level A4 during the period when the processing tool T returns from the bottom hole position Pz to the overlapping control start position Po (i.e., time To).

[0070] That is, in Figure 2In the section from the machining start position Ps to the contact position Pp via the reference position Pr, the load data WD2 is shifted at the first amplitude level A1. When the machining tool T contacts the workpiece W at the contact position Pp and starts cutting, the load data WD2 changes to the second amplitude level A2. Then, in the cutting section to the hole bottom position Pz, the load data WD2 continuously increases from the second amplitude level A2 to the third amplitude level A3. After that, when the machining tool T reaches the hole bottom position Pz and switches to the tool being pulled out and returns, the load data WD2 changes to the fourth amplitude level A4.

[0071] Next, in the tool return interval from the hole bottom position Pz to the overlap control start position Po, the load data WD2 is shifted at the fourth amplitude level A4, and when the front end of the machining tool T is pulled out of the workpiece W, the load data WD2 returns to the first amplitude level A1. After that, since there is no contact between the machining tool T and the workpiece W, the load data WD2 is shifted at the first amplitude level A1 in the interval from the overlap control start position Po to the next machining start position Ps'.

[0072] According to the above, in the second embodiment, the load data WD2 is measured as a physical quantity in the machining, and if the timing of switching from the fourth amplitude level A4 to the first amplitude level A1 can be determined, the overlap control start position Po for directly switching to the overlap control in the machining of the fixed cycle can be detected. That is, the numerical control device of the second embodiment of the present invention operates in the following manner: the load data WD2 is measured as a physical quantity representing the machining state in the machining, the overlap control start position Po is determined based on the load data WD2, and when it is determined that the machining tool T has reached the overlap control start position Po, the overlap control is executed.

[0073] As described above, the numerical control device and the numerical control method according to the second embodiment of the present invention can directly measure the physical quantity indicating the machining state of the machining tool in addition to the effects obtained in the first embodiment, and thus can more accurately determine the timing of transition to the overlap control.

[0074] <Third embodiment>

[0075] Figure 7 FIG. 1 is a partial cross-sectional view showing an example of movement control of a machining tool based on a fixed cycle according to a third embodiment. Figure 1 to Figure 5 In the block diagrams, flow charts, and the like shown in the drawings, portions that can adopt the same or common configurations as those of the first embodiment are denoted by the same reference numerals and their repeated descriptions are omitted.

[0076] like Figure 7As shown, in the machining control of the third embodiment, the machining tool T moves to the reference position Pr via the machining start position Ps as in the first embodiment. At this time, the machining tool T may be in a rotating state in advance or may rotate at the machining start position Ps.

[0077] Next, the machining tool T rotates while contacting the workpiece W at the contact position Pp and cutting in the Z direction to the hole bottom position Pz having a predetermined depth D. At this time, as in the case of the first embodiment, the cutting from the contact position Pp to the hole bottom position Pz may be performed in a plurality of times in consideration of the load applied to the machining tool T.

[0078] The processing tool T that has completed the drilling process up to the hole bottom position Pz is returned in a fast forward manner in the Z direction while rotating to the same height as the surface of the workpiece W. At this time, in the third embodiment, the control start position Po' with an allowance is obtained by adding a predetermined allowance movement amount M in the drawing direction (Z direction) to the overlap control start position Po shown in the first embodiment through calculation, and the control start position Po' with an allowance is used as a judgment index for the start of overlap control.

[0079] That is, in the third embodiment, when it is determined that the machining tool T returning from the hole bottom position Pz has reached the control start position Po' with the allowance, the movement control of the machining tool T is performed by the overlap control in which the feed in the Z direction and the feed in the X direction of the machining tool T overlap each other. Thus, in the first embodiment, the virtual overlap control start position Po is located on the surface of the workpiece W, whereas in the third embodiment, the start position of the overlap control is a position away from the surface of the workpiece W by the allowance movement amount M.

[0080] As described above, in addition to the effects obtained in the first and second embodiments, the numerical control device and numerical control method of the third embodiment of the present invention can reduce the risk of interference between the processing tool and the workpiece surface when the movement component in the X direction is overlapped in the overlapping control by setting the starting position of the overlapping control to a position away from the workpiece surface by the excess movement amount.

[0081] The present invention is not limited to the above-described embodiment, and can be modified appropriately without departing from the gist of the invention. The present invention can modify any structural element of the embodiment or omit any structural element of the embodiment within the scope of the invention.

[0082] Description of Reference Numerals

[0083] 10 Processing equipment

[0084] 12Processing Control Department

[0085] 14Acoustic Sensor

[0086] 16 Load Cells

[0087] 20External storage devices

[0088] 100 Numerical Control Devices

[0089] 110 Main control unit

[0090] 120 Processing program analysis department

[0091] 130 Processing status measurement unit

[0092] 140 Start position determination unit

[0093] Ps processing start position

[0094] Pr reference position

[0095] Pp contact position

[0096] Pz hole bottom position

[0097] Po overlap control start position

[0098] Po' is the control start position Po' with a margin.

Claims

1. A numerical control device that controls the movement of a machining tool through a fixed cycle. It is characterized in that The numerical control device comprises: A main control unit that issues processing instructions to the processing device based on the processing program; a machining program analyzing unit that pre-reads and analyzes the machining program; a processing state measuring unit that measures a physical quantity indicating a processing state during processing; and a start position determination unit that determines an overlap control start position based on the physical quantity, The main control unit executes the overlap control of the processing tool when it is determined that the processing tool has reached the overlap control start position.

2. The numerical control device according to claim 1, It is characterized in that The overlap control start position is determined based on the change in the physical quantity.

3. The numerical control device according to claim 2, It is characterized in that The overlap control start position is determined based on the physical quantity at an initial contact position between the workpiece and the processing tool.

4. The numerical control device according to any one of claims 1 to 3, It is characterized in that The overlap control start position is determined by adding a predetermined margin movement amount.

5. The numerical control device according to any one of claims 1 to 3, It is characterized in that The physical quantity is processing sound or vibration during processing.

6. The numerical control device according to any one of claims 1 to 3, It is characterized in that The physical quantity is a machining load on the machining tool during machining.

7. A numerical control method for controlling the movement of a machining tool by a fixed cycle, It is characterized in that The numerical control method comprises the following steps when pre-reading the machining program and issuing machining instructions to the machining device: The step of measuring a physical quantity representing a processing state during processing; A step of determining an overlap control start position based on the physical quantity; and When it is determined that the processing tool has reached the overlap control start position, a step of executing the overlap control of the processing tool is performed.

8. The numerical control method according to claim 7, It is characterized in that The overlap control start position is determined based on the change in the physical quantity.

9. The numerical control method according to claim 8, It is characterized in that The overlap control start position is determined based on the physical quantity at an initial contact position between the workpiece and the processing tool.

10. The numerical control method according to any one of claims 7 to 9, It is characterized in that The overlap control start position is determined by adding a predetermined margin movement amount.

11. The numerical control method according to any one of claims 7 to 9, It is characterized in that The physical quantity is processing sound or vibration during processing.

12. The numerical control method according to any one of claims 7 to 9, It is characterized in that The physical quantity is a machining load on the machining tool during machining.

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