JP2015187799A - Numerical control apparatus and control method of numerical control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a numerical control apparatus that can blow away chips wound on a tool without extending work time of a fixed cycle, and to provide a control method of the numerical control apparatus.SOLUTION: While rotating the main shaft in a single direction, the CPU of the numerical control apparatus moves down the main shaft head to contact the tool 4A with a work-piece, so as to perform drilling on the work-piece. The CPU moves up the main shaft head to the return point from the Z point that is a hole bottom position formed on the work-piece. The CPU starts the chip removal operation in the time when the main shaft head reaches the return point from the Z point. The chip removal operation is to reversely rotate the main shaft. Thus, the numerical control apparatus can absorb the whole or a part of the time required for the chip removal operation by the time when the main shaft head reaches the return point. Therefore, it is possible to shorten the work time required for the drilling cycle.

Description

  The present invention relates to a numerical control device and a control method for the numerical control device.

  The numerical controller performs drilling by a drill cycle or a tap cycle using an NC program. Chips are generated from the workpiece when drilling. The generated chips are wound around the drill. If the numerical control device continues processing in a state where chips are wound around the drill, there is a possibility that the workpiece may be defective or the tool may be broken. The chip removal device disclosed in Patent Document 1 rotates the cutter in reverse in order to fly off the chips wound around the cutter (tool) after the spindle unit is lifted and returned to the initial position after the completion of processing.

Japanese Utility Model Publication No. 4-5343

  In the chip removal device described in Patent Document 1, there is a problem that even if the chips wound around the cutter can be blown, the time for reverse rotation of the cutter increases, so that the working time is extended. .

  An object of the present invention is to provide a numerical control apparatus and a control method for the numerical control apparatus that can blow off chips wound around a tool without extending the working time of a fixed cycle.

  A numerical control device according to a first aspect of the present invention includes a movement of a spindle head of a machine tool provided so as to be capable of reciprocating in a direction opposite to one direction toward a work table that supports a workpiece, and a rotation support supported by the spindle head. And a numerical control device comprising a control means for controlling the rotation of the spindle on which the tool is mounted, wherein the control means moves the spindle head in the one direction while rotating the spindle in a predetermined direction, to the workpiece. Drilling means for making a hole by contacting the tool, moving means for moving the spindle head in the opposite direction from a position after the drilling by the drilling means toward a return point separated from the workpiece, and the moving means Thus, the spindle rotates in the direction opposite to the predetermined direction until the spindle head moves in the opposite direction from the position after drilling and reaches the return point. Characterized in that a reverse rotation means starts to rotate. Since the numerical control device performs the reverse rotation operation of the spindle after the drilling is completed, the chips wound around the tool can be blown off. The reverse rotation operation starts after the end of drilling and before the spindle head moves in the opposite direction from the position after drilling and reaches the return point. Therefore, the numerical control device can absorb all or part of the time required for the reverse rotation operation in the time until the spindle head reaches the return point, so that the work time required for the fixed cycle can be shortened.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, the numerical control device until the spindle head moves in the opposite direction from the position after the drilling and reaches the return point by the moving means. Further comprising start position designating means for designating a start position of the reverse rotation operation by the reverse rotation means, wherein the reverse rotation means performs the reverse rotation operation at the start position designated by the start position designating means. It is characterized by starting. For example, when the spindle head moves in the opposite direction, the numerical control device can designate the position immediately after the tool comes out of the workpiece as the start position. Therefore, since the numerical control device can start the reverse rotation operation quickly, the working time can be shortened.

  In addition to the configuration of the invention described in claim 1 or 2, the numerical control device according to claim 3 includes the continuous execution means for continuously executing the drilling by the drilling means, and the drilling means by the continuous execution means. A frequency designating unit that designates a frequency of executing the reverse rotation operation by the reverse rotation unit when the drilling is continuously performed, wherein the reverse rotation unit is designated by the frequency designating unit. The reverse rotation operation is performed based on the frequency. The numerical control device can shorten the work time even when drilling continuously. Since the numerical control device can specify the frequency of the reverse rotation operation, it can save power consumption for the reverse rotation operation as compared with the case of performing the reverse rotation operation every time.

  According to a fourth aspect of the present invention, in addition to the configuration of the invention according to any one of the first to third aspects, the numerical control device according to a fourth aspect of the present invention is configured so that at least the perforation means performs the perforation with respect to the rotational speed of the spindle during the reverse rotation operation. The rotation speed is less than or equal to the rotation speed of the main shaft when executed. The rotation speed of the main shaft during the reverse rotation operation is at least equal to or lower than the rotation speed of the main shaft when drilling. Therefore, the numerical control device can quickly return the rotation direction of the main shaft to perform the next drilling process. The working time for continuous drilling is shortened.

  According to a fifth aspect of the present invention, there is provided a method for controlling a numerical control apparatus, comprising: moving a spindle head of a machine tool provided so as to be capable of reciprocating in a direction opposite to one direction toward a work table supporting a workpiece; and rotating the spindle head In a control method of a numerical control device for controlling the rotation of a spindle on which the tool is supported and the tool is mounted, the spindle head is moved in the predetermined direction while rotating the spindle in a predetermined direction, and the tool is brought into contact with the workpiece In the drilling step of drilling, the moving step of moving the spindle head in the opposite direction from the position after the drilling in the drilling step toward the return point separated from the workpiece, and the moving step, the spindle A reverse rotational movement in which the head rotates in the direction opposite to the predetermined direction while the head moves in the opposite direction from the position after the drilling and reaches the return point. Characterized by comprising a reverse rotation process to start. The numerical control apparatus can obtain the same effect as that of claim 1 by performing the moving path correction method.

1 is a perspective view of a machine tool 1. FIG. 3 is a block diagram showing an electrical configuration of the machine tool 1 and the numerical control device 30. The figure which shows the process of a drill cycle. The figure which shows the process of a tap cycle. The flowchart of a fixed cycle control process. 6 is a flowchart showing a continuation of FIG. FIG. 7 is a flowchart showing a continuation of FIG. 6.

  Embodiments of the present invention will be described with reference to the drawings. In the following description, the top, bottom, left and right, front and back indicated by arrows in the figure are used. The left-right direction, the front-rear direction, and the vertical direction of the machine tool 1 are an X-axis direction, a Y-axis direction, and a Z-axis direction, respectively. A machine tool 1 shown in FIG. 1 is a machine that rotates a tool 4 mounted on a spindle 9 at a high speed and performs a cutting process on a work 3 held on a work table 10. The numerical control device 30 (see FIG. 2) controls the operation of the machine tool 1.

  The structure of the machine tool 1 will be described with reference to FIG. The machine tool 1 includes a base 2, a column 5, a spindle head 7, a spindle 9, a work table 10, a tool changer 20, a control box 6, an operation panel (not shown), and the like. The base 2 is a substantially rectangular parallelepiped base made of metal. The column 5 is a prism that is erected on the upper rear side of the base 2. The spindle head 7 is provided so as to be movable in the Z-axis direction along the front surface of the column 5. The spindle head 7 supports the spindle 9 rotatably inside. The spindle 9 has a mounting hole (not shown) in the lower part of the spindle head 7. The main shaft 9 is mounted with the tool 4 in the mounting hole, and is rotated by driving a main shaft motor 52 (see FIG. 2). The spindle motor 52 is provided on the spindle head 7.

  The spindle head 7 is moved in the Z-axis direction by a Z-axis moving mechanism provided on the front surface of the column 5. The Z-axis moving mechanism includes a pair of Z-axis linear guides (not shown), a Z-axis ball screw (not shown), and a Z-axis motor 51 (see FIG. 2). The Z-axis linear guide extends in the Z-axis direction and guides the spindle head 7 in the Z-axis direction. The Z-axis ball screw is disposed between a pair of Z-axis linear guides and is rotatably provided by an upper bearing portion (not shown) and a lower bearing portion (not shown). The spindle head 7 includes a nut (not shown) on the back surface. The nut is screwed onto the Z-axis ball screw. The Z-axis motor 51 rotates the Z-axis ball screw in the forward and reverse directions. Therefore, the spindle head 7 moves in the Z-axis direction together with the nut. The numerical controller 30 controls the spindle head 7 so as to be movable in the Z-axis direction by controlling the driving of the Z-axis motor 51.

  The work table 10 is provided in the upper center of the base 2 and is moved in the X-axis direction and the Y-axis direction by an X-axis motor 53 (see FIG. 2), a Y-axis motor 54 (see FIG. 2), a guide mechanism (not shown), etc. Is possible. The numerical controller 30 controls the operation of the X-axis motor 53 and the Y-axis motor 54 so that the work table 10 can be moved in the X-axis direction and the Y-axis direction.

  The tool changer 20 is provided on the front side of the spindle head 7. The tool changer 20 includes a disk-shaped tool magazine 21. The tool magazine 21 holds a plurality of tools (not shown) radially on the outer periphery, and indexes the tool indicated by the tool change command to the tool change position. The tool change command is commanded by the NC program. The tool change position is the lowest position of the tool magazine 21. The tool changer 20 exchanges and exchanges the tool 4 mounted on the spindle 9 and the tool at the tool change position.

  The control box 6 stores the numerical control device 30. The numerical control device 30 controls the Z-axis motor 51, the X-axis motor 53, and the Y-axis motor 54, and moves the workpiece 3 held on the work table 10 and the tool 4 mounted on the spindle 9 to move variously. Processing is performed on the workpiece 3. The various types of processing include drilling and tapping including side processing such as milling.

  With reference to FIG. 2, the electrical configuration of the numerical controller 30 and the machine tool 1 will be described. The numerical control device 30 includes a CPU 31, a ROM 32, a RAM 33, a nonvolatile storage device 34, an input / output unit 35, drive circuits 51A to 55A, and the like. The CPU 31 performs overall control of the numerical control device 30. The ROM 32 stores various programs including a main program and a fixed cycle control program. The main program executes main processing. The main process reads the NC program block by block and executes various operations. The fixed cycle program executes a fixed cycle control process (see FIGS. 5 to 7) described later.

  The RAM 33 temporarily stores data during execution of various processes. The nonvolatile storage device 34 stores an NC program, various parameters, and the like. The NC program is composed of a plurality of blocks including various control commands, and controls various operations including axis movement of the machine tool 1, tool change, and the like in units of blocks. The CPU 31 stores the NC program input and set by the operator using the input unit 24 in the nonvolatile storage device 34.

  The drive circuit 51A is connected to the Z-axis motor 51 and the encoder 51B. The drive circuit 52A is connected to the spindle motor 52 and the encoder 52B. The drive circuit 53A is connected to the X-axis motor 53 and the encoder 53B. The drive circuit 54A is connected to the Y-axis motor 54 and the encoder 54B. The drive circuit 55A is connected to a magazine motor 55 that drives the tool magazine 21 and an encoder 55B. The drive circuits 51A to 55A receive commands from the CPU 31 and output drive currents to the corresponding motors 51 to 55 and the motors that drive the tool changer 56, respectively. The drive circuits 51A to 55A receive feedback signals from the encoders 51B to 55B and perform position and speed feedback control. The input / output unit 35 is connected to the input unit 24 and the display unit 25, respectively.

  With reference to FIG. 3, the process of the drill cycle which has a chip removal operation | movement is demonstrated. In the chip removal operation of the drill cycle, the main shaft 9 is rotated in the opposite direction to the current M03 (or M04) modal (hereinafter referred to as reverse rotation), and the chips wound around the tool 4A are removed. The tool 4A is a drill tool. The drill cycle of this embodiment includes steps 70 to 74 in order. Step 70 is a step of moving the spindle head 7 at a rapid feed from the reference position toward the drilling position. The reference position is a reference position when performing a fixed cycle. The drilling position means a drilling position in the XY axis plane. Step 71 is a step of moving the spindle head 7 at a rapid feed from the drilling position toward the point R. Point R is a position at which cutting feed is started toward point Z. The R point may be set, for example, so that the tip of the tool 4A attached to the main shaft 9 has substantially the same height as the surface of the workpiece 3. The point Z is the position of the hole bottom formed in the workpiece 3.

  Step 72 is a step of moving from the R point toward the Z point at a cutting feed rate. Step 73 is a step of moving (lowering) from the Z point toward the R point by rapid traverse. Step 74 is a step in which the chip removal operation is started from the point R and moved (raised) toward the return point by fast-forwarding. The return point is the same position as the drilling position. In step 74, point R is the starting position for the chip removal operation. In FIG. 3, thin line arrows indicating steps 70, 71, 73, and 74 indicate fast-forward movement. A thick arrow indicating step 72 indicates movement at a cutting feed rate. An example of the Z position of each of the Z point, the R point, and the return point is a Z point (Z = 360), an R point (Z = 400), and a return point (Z = 450). Each numerical value of Z indicates the height from the surface of the work table 10 and the unit is mm. The numerical control device 30 can process a plurality of holes in the workpiece 3 by repeatedly executing a series of operations in steps 70 to 74. The numerical controller 30 performs the chip removal operation while moving toward the return point in Step 74.

A command format of a drill cycle having a chip removal operation will be described. The drill cycle can be commanded with G81 or G82. An example of a drill cycle command format defined by the NC program is shown below.
“G81 X_Y_Z_R_P_F_U_K_E_;”
-X, Y: Drilling position-Z: Hole bottom position-R: R point position-P: Dwell time-F: Cutting feed rate-U: Chip removal spindle speed-K: Number of repetitions-E: Chip removal Execution interval X, Y, Z, R, P, F, U, K, and E are addresses of control commands.

  X and Y designate the distance from the reference position in the incremental mode. Z specifies the distance from the point R to the hole bottom in the incremental mode. R designates the distance from the drilling position to point R in the incremental mode. The dwell time is the time to wait at the Z point, and the time unit is the same as when G04 is specified. G04 is the G code of Dwell. The chip removal spindle speed is the reverse rotation speed of the spindle 9 during the chip removal operation. The number of repetitions is the number of repetitions of the drill cycle. The chip removal execution interval is an interval at which the chip removal operation is performed when the drill cycle is repeated, and corresponds to the frequency at which the chip removal operation is performed. As will be described later, it is preferable that the chip removal spindle speed is at least equal to or less than the speed of the spindle 9 during drilling.

  With reference to FIG. 4, the process of the tap cycle which has a chip removal operation | movement is demonstrated. The tap cycle of this embodiment includes steps 80 to 84 in order. In the chip removal operation of the tap cycle, the main shaft 9 is rotated in the opposite direction to the tap operation (hereinafter referred to as reverse rotation), and the chips wound around the tool 4B are removed. The tool 4B is a tap tool. The tap operation is an operation in which the main shaft 9 is rotated forward at a predetermined rotation speed (5000 rpm in the present embodiment).

  Step 80 is a step of moving the spindle head 7 from the reference position toward the tap position by rapid feed. The tap position means a processing position on the XY axis plane. Step 81 is a step of moving the spindle head 7 from the tap position toward the point R by rapid traverse. R point and Z point have the same definition as in the drill cycle. Step 82 is a step of moving from the R point toward the Z point at a cutting feed rate. Step 83 is a step of moving from the Z point toward the R point while reversing at the cutting feed rate. Step 84 is a step of starting the chip removing operation from the point R and moving toward the return point by fast-forwarding. In step 84, point R is the starting position for the chip removal operation. In FIG. 4, thin line arrows indicating steps 80, 81, and 84 indicate fast-forward movement. Thick line arrows indicating steps 82 and 83 indicate movement at the cutting feed rate. The numerical control device 30 can process a plurality of screw holes in the workpiece 3 by repeatedly executing a series of operations in steps 80 to 84. The numerical controller 30 performs a chip removal operation while moving toward the return point in step 84.

A command format of a tap cycle having a chip removal operation will be described. The drill cycle can be commanded with G84. An example of a tap cycle command format is shown below.
“G84 X_Y_Z_R_P_F_S_U_K_E_;”
The various addresses are the same as the drill cycle command format. S is the spindle speed.

  A fixed cycle control process executed by the CPU 31 will be described with reference to the flowcharts of FIGS. 3, 4, and 5 to 6. In the present embodiment, cases where the NC programs of Example 1 and Example 2 are executed will be described in order.

Description will be made assuming that the NC program of Example 1 is executed.
・ Example 1: NC program of drill cycle command “G90 G00 X0 Y0 Z450. M03 S5000;”
"G91 G81 X-10. Y-10. Z-90. R-50. P2. F3000. U2000 K6 E2;"
“M30;”
The first line is a command “Move the spindle 9 and the spindle head 7 to the position of (x, y, z) = (0, 0, 450) by fast-forward at 5000 revolutions in the normal direction.” It is. (0, 0, 450) is a reference position. The second line is a drill cycle command having a chip removal operation. M30 in the third line is an end command. The address values specified in Example 1 are as follows.
-Drilling position (X, Y): Position from the reference position (-10, -10, 450)-Hole bottom position (Z): -90 position from the drilling position-R point position (R) = From the Z point- 50
・ Dwell time (P) = 2 seconds ・ Cutting feed rate (F) = 3000 mm / min
-Chip removal spindle speed (U) = 2000 mm / min
・ Repetition count (K) = 6 times ・ Chip removal execution interval (E) = 2 cycles

  The CPU 31 executes the main process and executes the NC program. The CPU 31 interprets the first line of the NC program, rotates the spindle 9 at 5000 rpm in the normal direction, and sets the spindle head 7 and the work table 10 at the reference position (x, y, z) = (0, 0, 450). To fast forward. The CPU 31 interprets the second line of the NC program. The second line has G81. G81 is a fixed cycle control command. The CPU 31 reads the fixed cycle control program from the ROM 32 and executes a fixed cycle control process.

  The CPU 31 initializes the counter p to zero (S1). The counter p counts the number of executions of the fixed cycle. The value of the counter p is stored in the RAM 33. The CPU 31 adds 1 to the counter p (S2). The CPU 31 starts moving the spindle head 7 and the work table 10 from the reference position of (0, 0, 450) to the drilling position of (-10, -10, 450) by rapid traverse (see S3, step 70 in FIG. 3). . In FIG. 3, the main shaft 9 is illustrated as moving in the XY directions, but this is for easy understanding, and the work table 10 actually moves. The CPU 31 determines whether or not the rotation speed of the main shaft 9 has reached 2000 rpm in the reverse rotation (S4). Since the main shaft 9 is not currently rotating in the reverse direction (S4: NO), the CPU 31 determines whether or not the main shaft 9 has reached the drilling position (S8). Until the spindle head 7 reaches the drilling position (S8: NO), the CPU 31 returns to S4 and waits (S4: NO, S8). The CPU 31 can detect the positions of the spindle head 7 and the work table 10 based on feedback signals output from the encoders 51B, 53B, and 54B.

  When the spindle head 7 reaches the drilling position (S8: YES), the CPU 31 starts descending the spindle head 7 (see step 71 in FIG. 3) by fast-forwarding from the drilling position toward the point R (S9). The CPU 31 determines whether or not the rotational speed of the spindle 9 has reached 2000 rpm in the reverse rotation (S10). Since the spindle 9 is not currently rotating in the reverse direction (S10: NO), the CPU 31 determines whether or not the spindle head 7 has reached the point R (S14). Until the spindle head 7 reaches the point R (S14: NO), the CPU 31 returns to S10 and continues to descend (S10: NO, S14).

  When the spindle head 7 reaches the point R (S14: YES), as shown in FIG. 6, the CPU 31 determines whether or not the fixed cycle being executed is a drill cycle (S20). Since G81 in the NC program is a drill cycle control command (S20: YES), the CPU 31 determines whether or not the spindle 9 is rotating forward (S21). Since the spindle 9 is rotating forward (S21: YES), the CPU 31 starts to lower the spindle head 7 from the R point to the Z point at a cutting feed rate = 3000 mm / min (S31). The tool 4A attached to the spindle 9 contacts the surface of the workpiece 3 and cuts the workpiece 3 to the Z point while rotating forward (see step 72 in FIG. 3). The tool 4A forms a hole (not shown) in the work 3.

  The CPU 31 determines whether or not the spindle head 7 has reached the Z point (S32). Until the spindle head 7 reaches the Z point (S32: NO), the CPU 31 continues to descend. When the spindle head 7 reaches the Z point (S32: YES), the CPU 31 performs a dwell for 2 seconds with the spindle 9 rotating forward (S33). Therefore, the tool 4A can surely cut the bottom of the hole.

  The CPU 31 determines again whether or not the fixed cycle being executed is a drill cycle (S34). Since the fixed cycle being executed is a drill cycle (S34: YES), as shown in FIG. 7, the CPU 31 starts to rise at a rapid feed from the Z point of the spindle head 7 toward the return point (S40, FIG. 3). Step 73). The CPU 31 determines whether or not the spindle head 7 has reached point R (S41). Until the spindle head 7 reaches point R (S41: NO), the CPU 31 continues to rise.

  When the spindle head 7 reaches the point R (S41: YES), the tool 4A is pulled upward from the hole formed in the workpiece 3. The CPU 31 determines whether or not the value of the counter p is a multiple of the chip removal execution interval E (S42). In the NC program of Example 1, the chip removal execution interval E = 2. In the first cycle, since the counter p = 1 (S42: NO), the CPU 31 determines whether the spindle head 7 has reached the return point without executing the chip removal operation (S48). Until the spindle head 7 reaches the return point (S48: NO), the CPU 31 continues to rise (S44: NO, S48, see step 74 in FIG. 3).

  When the spindle head 7 has reached the return point (S48: YES), since the first cycle has ended, the CPU 31 determines whether or not the value of the counter p is equal to or greater than the number of repetitions (S49). In Example 1, the number of repetitions K = 6. Since the counter p is 1 at the end of the first cycle (S49: NO), the CPU 31 returns to S2 in FIG. 5, adds 1 to the counter p, and executes the process in the second cycle in the same manner as in the first cycle. To do.

  In step 73 (see FIG. 3) in the second cycle, after a dwell of 2 seconds at the Z point, the CPU 31 starts to lift the spindle head 7 toward the return point by rapid traverse (S40). When the spindle head 7 reaches the point R (S41: YES), the CPU 31 determines whether or not the value of the counter p is a multiple of the chip removal execution interval E = 2 (S42). In the second cycle, since the counter p = 2 (S42: YES), in order to remove the chips wound around the tool 4A, the CPU 31 rotates the spindle 9 in the reverse direction (chip removal operation) with 2000 rpm as the target rotational speed. ) Is started (S43). As described above, when the spindle head 7 rises to the point R, the tool 4A is pulled upward from the hole formed in the workpiece 3. The chips wound around the reversely rotating tool 4A are blown away by centrifugal force. Based on the feedback signal output from the encoder 52B of the spindle motor 52, the CPU 31 determines whether or not the rotation speed of the spindle 9 has reached 2000 rpm in the reverse rotation (S44).

  When the rotation speed of the main shaft 9 reaches 2000 rpm in the reverse rotation (S44: YES), almost all the chips wound around the tool 4A are blown off. The CPU 31 determines whether the fixed cycle being executed is a drill cycle (S45). Since the fixed cycle being executed is a drill cycle (S45: YES), the CPU 31 returns the main shaft 9 to 5000 rpm by normal rotation (S46), and ends the chip removal operation. Therefore, since the numerical control device 30 can absorb the time required for the chip removal operation by the time required for the movement of the spindle head 7 from the Z point to the return point, the work time can be shortened.

  The CPU 31 determines whether the spindle head 7 has reached the return point (S48). Until the spindle head 7 reaches the return point (S48: NO), the CPU 31 returns to S44 and continues to rise (S44: NO, S48). When the spindle head 7 reaches the return point (S48: YES), the CPU 31 determines whether or not the value of the counter p is equal to or greater than the number of repetitions K (= 6) (S49). Since the counter p is 2 (S49: NO), the CPU 31 returns to S2 in FIG. 5 to add 1 to the counter p in order to execute the third cycle. The value of the counter p is 3.

  On the other hand, when the spindle head 7 reaches the return point (S48: YES) before the rotation speed of the spindle 9 reaches 2000 rpm in reverse (S44: NO in FIG. 7), the CPU 31 rotates the spindle 9 in the reverse direction. In this state, it is determined whether the value of the counter p is equal to or greater than the number of repetitions K (= 6) (S49). Since the counter p is 2 (S49: NO), the CPU 31 returns to S2 in FIG. 5 to add 1 to the counter p (S2) in order to execute the third cycle. The CPU 31 starts moving the spindle head 7 by fast-forwarding from the return point to the next drilling position with the spindle 9 rotating in the reverse direction (S3). The CPU 31 determines whether or not the rotational speed of the spindle 9 has reached 2000 rpm in the reverse rotation (S4). When the rotation speed of the main shaft 9 is reverse and does not reach 2000 rpm (S4: NO), until the main shaft head 7 reaches the drilling position (S8: NO), the CPU 31 returns to S4 and continues to the drilling position. (S4: NO, S8).

  When the rotational speed of the spindle 9 reaches 2000 rpm in reverse (S4: YES), the CPU 31 determines whether or not the fixed cycle being executed is a drill cycle (S5). Since the fixed cycle being executed is a drill cycle (S5: YES), the CPU 31 returns the spindle 9 to 5000 rpm by normal rotation (S6), and ends the chip removal operation. Even in such a case, the numerical control device 30 can absorb the time required for the chip removal operation by the time required to move from the Z point to the next drilling position via the return point, so that the work time can be shortened. When the spindle head 7 reaches the drilling position (S8: YES) before the rotational speed of the spindle 9 reaches 2000 rpm in the reverse rotation (S4: NO), the CPU 31 keeps the spindle 9 in the reverse rotation state. Then, the spindle head 7 starts to move forward from the drilling position toward the point R (S9).

  The CPU 31 determines whether or not the rotational speed of the spindle 9 has reached 2000 rpm in the reverse rotation (S10). When the rotational speed of the main shaft 9 does not reach 2000 rpm due to reverse rotation (S10: NO), the CPU 31 returns to S10 and continues to the R point until the main shaft head 7 reaches the R point (S14: NO). (S10: NO, S14).

  When the rotational speed of the spindle 9 reaches 2000 rpm in the reverse rotation (S10: YES), the CPU 31 determines whether or not the fixed cycle being executed is a drill cycle (S11). Since the fixed cycle being executed is a drill cycle (S11: YES), the CPU 31 returns the main shaft 9 to 5000 rpm by normal rotation (S12), and ends the chip removal operation. Even in such a case, the numerical control device 30 can absorb the time required for the chip removal operation by the time required to move from the Z point to the R point via the return point and the next drilling position, thereby reducing the work time. it can.

  Before the spindle head 7 reaches the point R (S14: YES) before the rotational speed of the spindle 9 reaches 2000 rpm in the reverse rotation (S10: NO), the workpiece 3 cannot be cut with the spindle 9 rotating in the reverse direction. . Therefore, as shown in FIG. 6, the CPU 31 determines whether or not the fixed cycle being executed is a drill cycle while the main shaft 9 is rotated in the reverse direction (S20). Since the fixed cycle being executed is a drill cycle (S20: YES), the CPU 31 determines whether or not the spindle 9 is rotating forward (S21). Since the spindle 9 is rotating in the reverse direction (S21: NO), the CPU 31 temporarily stops the spindle head 7 from descending (S22).

  The CPU 31 determines whether or not the rotational speed of the main shaft 9 has reached 2000 rpm in the reverse rotation (S23). Until the rotational speed of the spindle 9 reaches 2000 rpm in reverse (S23: NO), the CPU 31 returns to S23 and waits for the spindle head 7 at the point R. When the rotational speed of the main shaft 9 reaches 2000 rpm by reverse rotation (S23: YES), the CPU 31 returns the main shaft 9 to 5000 rpm by normal rotation (S24), and after the chip removal operation is completed, from the R point to the Z point The movement is started at a cutting feed rate of 3000 mm / min (S31). In step 74 shown in FIG. 3, when the spindle 9 is reversely rotated and does not reach 2000 rpm even when the R point of the next cycle is reached, the movement of the spindle head 7 toward the Z point is temporarily stopped. Since movement toward the Z point is started when reaching 2000 rpm, it is possible to reliably prevent the tool 4A from coming into contact with the workpiece 3 in the reversely rotated state.

  The CPU 31 repeatedly executes the above processing, and when the value of the counter p reaches 6, the number of repetitions is reached (S49: YES). Therefore, the CPU 31 ends this processing, and 6 holes are formed in the work 3. Therefore, the numerical control device 30 can remove the chips wound around the tool 4A by performing the chip removal operation during execution of the drill cycle. Since the chips wound around the tool 4 </ b> A can be removed, the tool 4 </ b> A can form a hole in the workpiece 3 satisfactorily.

  In Example 1, since the chip removal execution interval E = 2, the CPU 31 performs the chip removal operation three times while repeating the above drill cycle six times. Since the numerical control device 30 can be carried out at an appropriate frequency while repeatedly executing the drill cycle, it is possible to save the power consumption associated with the chip removal operation. This is because the electric power is less when the main shaft is continuously rotated in the same direction than when the main shaft is rotated in the reverse direction. The chip removal execution interval can be freely changed by the input unit 24 of the operation panel. For example, the amount of chips wound around the tool 4 varies depending on the type of tool, the material of the workpiece 3 and the like. Therefore, the user can efficiently remove the chips wound around the tool 4 by lengthening or shortening the chip removal execution interval according to the type of the tool, the material of the workpiece 3, and the like.

  In Example 1, the chip removal execution interval E = 2, but when the E address is omitted, the CPU 31 performs the chip removal operation every time the drill cycle is repeated. In that case, the CPU 31 performs the chip removal operation from the first drill cycle.

Description will be made assuming that the NC program of Example 2 is executed. The NC program of Example 2 is a tap cycle as follows.
・ Example 2: NC program of tap cycle command “G90 G00 X0 Y0 Z450 .;”
"G91 G84 X-10. Y-10. Z-90. R-50. P2. F3000 S5000. U2000 K6 E2;"
“M30;”
The first line is a command “Move to the position of (x, y, z) = (0, 0, 450) by rapid traverse”. The third line is the same as in Example 1. The address value specified in Example 2 is the same as in Example 1. The spindle speed (S) is 5000 rpm. In the present embodiment, the description of operations common to the drill cycle will be simplified, and the operations characteristic of the tap cycle will be mainly described.

  The CPU 31 interprets the first line of the NC program, and moves the spindle head 7 to the position of (x, y, z) = (0, 0, 450) by rapid traverse. The CPU 31 interprets the second line of the NC program. The second line has G84. G84 is also a fixed cycle control command. The CPU 31 reads the fixed cycle control program from the ROM 32 and executes the fixed cycle control process.

  The CPU 31 initializes the counter p to zero and then adds 1 (S1, S2). The CPU 31 starts the fast-forward movement of the workbench 10 from the current position toward the tap position (−10, −10, 0) (S3, refer to step 80 in FIG. 4). In FIG. 4, the main shaft 9 is illustrated as moving in the XY directions, but this is for easy understanding, and the work table 10 actually moves. Since the spindle 9 is not currently rotating in the reverse direction (S4: NO), the CPU 31 determines whether or not the workbench 10 has reached the tap position (S8). When the work table 10 reaches the tap position (S8: YES), the CPU 31 starts the fast-forward movement of the spindle head 7 from the tap position toward the R point (see step 81 in FIG. 4) (S9). Since the spindle 9 is not currently rotating in the reverse direction (S10: NO), the CPU 31 determines whether or not the spindle head 7 has reached the point R (S14).

  When the spindle head 7 reaches the point R (S14: YES), as shown in FIG. 6, the CPU 31 determines whether or not the fixed cycle being executed is a drill cycle (S20). Since G84 is a control command for the tap cycle (S20: NO), the CPU 31 determines whether or not the spindle 9 is rotating in reverse (S25). Since the main shaft 9 is not rotating backward (S25: NO), the CPU 31 starts a tap operation (S26). The CPU 31 starts to descend from the R point to the Z point at a cutting feed rate = 3000 mm / min (S31). The tool 4B attached to the spindle 9 contacts the surface of the workpiece 3 and cuts the workpiece 3 to the Z point while rotating forward (see step 82 in FIG. 4). The tool 4B forms a screw hole (not shown) in the work 3. When the spindle head 7 reaches the Z point (S32: YES), the CPU 31 performs a dwell for 2 seconds with the spindle 9 rotating forward (S33). Therefore, the tool 4B can cut the hole bottom reliably.

  The CPU 31 determines again whether or not the fixed cycle being executed is a drill cycle (S34). Since the fixed cycle being executed is a tap cycle (S34: NO), the CPU 31 reverses the rotation of the spindle 9 in order to remove the tool 4B from the workpiece 3, and the cutting feed rate is 3000 mm / min. The spindle head 7 starts to rise toward the point (S35, see step 83 in FIG. 4). The CPU 31 determines whether or not the spindle head 7 has reached the point R (S36). Until the spindle head 7 reaches point R (S36: NO), the CPU 31 continues to rise.

  When the spindle head 7 reaches the point R (S36: YES), the tool 4B is pulled upward from the screw hole formed in the workpiece 3. The CPU 31 stops the rotation of the spindle 9 and ends the tap operation (S37). The CPU 31 starts to raise the spindle head 7 with rapid traverse toward the return point (S38).

  As shown in FIG. 7, the CPU 31 determines whether or not the value of the counter p is a multiple of the chip removal execution interval E (S42). When the value of the counter p is not a multiple of the chip removal execution interval E (S42: NO), the CPU 31 determines whether or not the spindle head 7 has reached the return point without executing the chip removal operation (S48). . When the spindle head 7 reaches the return point (S48: YES), if the value of the counter p is less than the number of repetitions (S49: NO), the CPU 31 returns to S2 in FIG. 5 and similarly for the next cycle. Execute the process.

  In step 83 (see FIG. 4) in the next cycle, after a dwell of 2 seconds at the Z point, the CPU 31 reverses the rotation of the spindle 9 and moves the spindle head 7 from the Z point toward the R point at the cutting feed speed. The ascent is started (S35). After the spindle head 7 reaches the R point (S36: NO), the CPU 31 ends the tap operation (S37), and starts to rise toward the return point by fast-forwarding (S38). Further, as shown in FIG. 7, when the value of the counter p is a multiple of the chip removal execution interval E = 2 (S42: YES), the CPU 31 starts reverse rotation (chip removal operation) of the spindle 9 (S43). ). As described above, when the spindle head 7 rises to the point R, the tool 4B is pulled upward from the screw hole formed in the workpiece 3. The chips wound around the reversely rotating tool 4B are blown away by centrifugal force. Based on the feedback signal output from the encoder 52B of the spindle motor 52, the CPU 31 determines whether or not the rotation speed of the spindle 9 has reached 2000 rpm in the reverse rotation (S44).

  When the rotational speed of the main shaft 9 reaches 2000 rpm in reverse (S44: YES), the CPU 31 determines whether or not the fixed cycle being executed is a drill cycle (S45). Since the fixed cycle being executed is a tap cycle (S45: NO), the CPU 31 stops the rotation of the spindle 9 (S47) and ends the chip removal operation. Therefore, since the numerical control device 30 can absorb the time required for the chip removal operation by the time required for the movement of the spindle head 7 from the Z point to the return point, the work time can be shortened.

  Until the spindle head 7 reaches the return point (S48: NO), the CPU 31 returns to S44 and continues to rise (S44: NO, S48). When the spindle head 7 reaches the return point (S48: YES), the CPU 31 determines whether or not the value of the counter p is equal to or greater than the number of repetitions K (= 6) (S49). When the value of the counter p is less than the number of repetitions K (= 6) (S49: NO), the CPU 31 returns to S2 in FIG. 5 and adds 1 to the counter p in order to execute the next cycle.

  On the other hand, when the spindle head 7 reaches the return point (S48: YES) before the rotational speed of the spindle 9 reaches 2000 rpm in the reverse rotation (S44: NO), the CPU 31 controls the spindle 9 as in Example 1. With the reverse rotation, the work table 10 is moved from the return point to the next tap position by fast-forwarding (S49: NO, S2, S3). The CPU 31 determines whether or not the rotational speed of the spindle 9 has reached 2000 rpm in the reverse rotation (S4).

  When the rotational speed of the main shaft 9 reaches 2000 rpm in reverse (S4: YES), since the fixed cycle being executed is a tap cycle (S5: NO), the CPU 31 stops the rotation of the main shaft 9 (S7). Ends the chip removal operation. Even in such a case, the numerical control device 30 can absorb the time required for the chip removal operation by the time required for the movement from the Z point to the next tap position via the return point, so that the work time can be shortened.

  On the other hand, when the spindle head 7 reaches the tap position (S8: YES) before the rotational speed of the spindle 9 reaches 2000 rpm in the reverse rotation (S4: NO), the CPU 31 controls the spindle 9 in the same manner as in Example 1. In a state in which the spindle head 7 is rotated in the reverse direction, the spindle head 7 starts to move forward from the tap position toward the point R (S9). The CPU 31 determines whether or not the rotational speed of the spindle 9 has reached 2000 rpm in the reverse rotation (S10).

  When the rotational speed of the main shaft 9 reaches 2000 rpm in the reverse rotation (S10: YES), since the fixed cycle being executed is a tap cycle (S11: NO), the CPU 31 stops the rotation of the main shaft 9 (S13). Ends the chip removal operation. Even in such a case, the numerical control device 30 can absorb the time required for the chip removal operation by the time required to move from the Z point to the R point via the return point and the next tap position, thereby reducing the work time. it can.

  On the other hand, when the spindle head 7 reaches the tap position (S14: YES) before the rotation speed of the spindle 9 reaches 2000 rpm in the reverse rotation (S10: NO), as shown in FIG. It is determined whether the fixed cycle that is being executed is a drill cycle in a state in which is reversely rotated (S20). Since the fixed cycle being executed is a tap cycle (S20: NO), the CPU 31 determines whether or not the spindle 9 is rotating in reverse (S25). When the spindle 9 is rotating in the reverse direction (S25: YES), when the spindle head 7 is lowered, the tool 4B cannot cut the workpiece 3 when the spindle 9 is rotated in the reverse direction. Therefore, the CPU 31 stops the lowering of the spindle head 7 (S27).

  The CPU 31 determines whether or not the rotational speed of the main shaft 9 has reached 2000 rpm in the reverse rotation (S28). Until the rotational speed of the main shaft 9 reaches 2000 rpm in reverse (S28: NO), the CPU 31 returns to S28 and waits. When the spindle head 7 stops moving, when it reaches 2000 rpm by reverse rotation (S28: YES), since the chips wound around the tool 4B are sufficiently removed, the CPU 31 stops the rotation of the spindle 9 (S29), After finishing the chip removal operation, the tap operation is started (S30).

  The CPU 31 starts moving from the R point to the Z point at a cutting feed rate F = 3000 mm / min (S31). The tool 4B attached to the spindle 9 contacts the surface of the workpiece 3 and moves while cutting the workpiece 3 to the Z point while rotating forward. In step 84 shown in FIG. 4, when the spindle 9 is rotated in the reverse direction and does not reach 2000 rpm even when the R point of the next cycle is reached, the movement of the spindle head 7 toward the Z point is temporarily stopped. Since the movement toward the Z point is started when reaching 2000 rpm, it is possible to reliably prevent the tool 4B from coming into contact with the workpiece 3 in the reversely rotated state.

  The CPU 31 repeatedly executes the above processing, and when the value of the counter p reaches 6, the number of repetitions is reached (S49: YES), so the CPU 31 ends this processing. Six screw holes are formed in the work 3. Therefore, the numerical controller 30 can remove the chips wound around the tool 4B by performing the chip removal operation during the execution of the tap cycle. Since the chips wound around the tool 4B can be removed, the tool 4B can satisfactorily form screw holes in the workpiece 3. Also in Example 2, since the chip removal execution interval E = 2, the CPU 31 performs the chip removal operation three times while repeating the above tap cycle six times. Since the numerical control device 30 can be carried out at an appropriate frequency during repeated execution of the tap cycle, it is possible to save the power consumption associated with the chip removal operation.

  In the above description, the CPU 31 that executes the processes of S26 and S31 corresponds to the punching means of the present invention. The CPU 31 that executes the processes of S35 and S40 corresponds to the moving means of the present invention. The CPU 31 that executes the process of S43 corresponds to the reverse rotation means of the present invention. The R address of the NC program corresponds to the start position specifying means of the present invention. The CPU 31 that executes the process of S49 corresponds to the continuous execution means of the present invention. The E address of the NC program corresponds to the frequency designation means of the present invention.

  As described above, the CPU 31 of the numerical controller 30 according to the present embodiment controls the rotation of the spindle 9 and the movement of the spindle head 7. The CPU 31 lowers the spindle head 7 while rotating the spindle 9 in one direction, and brings the tool 4 into contact with the workpiece 3 to perform drilling or tapping on the workpiece 3. The CPU 31 raises the spindle head 7 from the Z point, which is the hole bottom position formed in the work 3, toward the return point. The CPU 31 starts the chip removal operation until the spindle head 7 reaches the return point from the Z point. The chip removal operation is an operation of rotating the main shaft 9 in the reverse direction. Therefore, since the numerical control device 30 can absorb all or part of the time required for the chip removal operation by the time until the spindle head 7 reaches the return point, the operation time can be shortened.

  In the above embodiment, the position of the R point where the chip removal operation is started can be specified by an address in the block of the NC program. The CPU 31 starts the chip removal operation from the point R designated by the address. Since the R point is designated by the address, the chip removal operation can be started during execution of the fixed cycle. Compared to the method of adding a line for executing the chip removal operation to the NC program, the work time can be shortened. Furthermore, when the spindle head 7 is lifted from the Z point, the position immediately after the tool 4 comes off the workpiece 3 can be designated as the R point. Therefore, since the numerical control device 30 can start the chip removal operation quickly, the operation time can be shortened.

  In the above embodiment, the number of repetitions of the fixed cycle and the interval at which the chip removal operation is performed can be specified by an address in the NC program block. The execution interval in the number of repetitions is the frequency at which the chip removal operation is executed during continuous execution of the fixed cycle. When drilling continuously, the CPU 31 performs a reverse rotation operation between the movement of the spindle head 7 after the drilling and the movement to the next drilling position. Therefore, the numerical controller 30 can shorten the working time even in continuous drilling. Furthermore, since the numerical controller 30 can designate the frequency of the chip removal operation, the power consumption for the chip removal operation can be saved as compared with the case where the chip removal operation is performed every time.

  Further, in the above embodiment, the rotational speed of the main shaft 9 during the chip removal operation is at least equal to or lower than the rotational speed of the main shaft 9 when drilling is performed. In the said embodiment, the rotation speed of the main shaft 9 at the time of drilling execution is 5000 rpm, and the rotation speed of the main shaft 9 during the chip removal operation is 2000 rpm. Therefore, since the numerical control device 30 can quickly return the rotation direction of the main shaft 9 to perform the next drilling process, it is possible to further reduce the work time required for continuous drilling. Furthermore, the load applied to the machine tool 1 when switching the rotation direction of the spindle 9 can be reduced.

  Needless to say, the numerical control device of the present invention is not limited to the above-described embodiment, and various modifications are possible. The above embodiment is a machine tool 1 in which the spindle on which the tool 4 is mounted is movable in the Z-axis direction, and the work table 10 is movable in two axes in the X-axis and Y-axis directions. The mechanism of the moving mechanism of the tool 4 that moves relative to the work table 10 in the X-axis, Y-axis, and Z-axis directions is not limited to the above embodiment. For example, a machine tool in which the main shaft is movable in three axes in the X-axis, Y-axis, and Z-axis directions and the work table is fixed may be used. The machine tool 1 of the above embodiment is a vertical machine tool, but may be a horizontal machine tool. The tool changer 56 may be omitted.

  In the above embodiment, the R point is set as the start point of the chip removal operation in the drill cycle and the tap cycle, but the chip removal operation start point may be designated at a position different from the R point. In that case, the chip removal operation start point may be designated by an address in the block of the NC program.

  In the above embodiment, the rotation speed of the spindle 9 at the time of drilling is 5000 rpm, and the rotation speed of the spindle 9 during the chip removal operation is 2000 rpm. However, the rotation speed of the spindle 9 during the chip removal operation is at least drilled. What is necessary is just to be below the rotation speed of the main shaft 9 at the time of execution. What is necessary is just to change the rotation speed of the main axis | shaft 9 according to various conditions, such as the kind of tool 4, the time of drilling, and the time of tapping.

  In the above embodiment, when the spindle 9 is rotating backward (S25: YES) when rising from the Z point during the tap cycle execution and reaching the R point (S25: YES), the spindle head 7 stops descending (S27). After the rotation speed reaches the predetermined rotation speed, the rotation of the main shaft 9 is temporarily stopped (S29) and then the tap operation is started (S30). However, the tap operation may be started after the predetermined rotation speed is reached.

  In the above embodiment, various programs are stored in the ROM 32, but may be stored in another storage device such as the nonvolatile storage device 34. Various programs may be stored in a memory card or the like, and various programs stored in the memory card may be read from a card slot (not shown) connected to the numerical control device 30. The NC program may be stored not in the nonvolatile storage device 34 but in the ROM 32 or a memory card.

  The fixed cycle control process (see FIGS. 5 to 7) of the above embodiment is not limited to the example executed by the CPU 31, and may be executed by other electronic components (for example, ASIC). Further, the fixed cycle process may be distributed by a plurality of electronic devices (for example, a plurality of CPUs).

DESCRIPTION OF SYMBOLS 1 Machine tool 3 Work 4 Tool 7 Spindle head 9 Spindle 10 Worktable 30 Numerical controller 31 CPU

Claims (5)

Control for controlling the movement of the spindle head of the machine tool provided so as to be reciprocable in one direction opposite to the work table supporting the workpiece, and the rotation of the spindle on which the tool head is rotatably supported and the tool is mounted. In a numerical control device comprising means,
The control means includes
Drilling means for moving the spindle head in the one direction while rotating the spindle in a predetermined direction and making the tool in contact with the workpiece to make a hole;
Moving means for moving the spindle head in the opposite direction from a position after the drilling by the drilling means toward a return point separated from the workpiece;
The moving means starts a reverse rotation operation for rotating the main shaft in a direction opposite to the predetermined direction until the main shaft head moves in the opposite direction from the position after drilling and reaches the return point. And a reverse rotation means. A start position designation for designating a start position of the reverse rotation operation by the reverse rotation means until the spindle head moves in the opposite direction from the position after drilling and reaches the return point by the moving means. Further comprising means,
The numerical control device according to claim 1, wherein the reverse rotation unit starts the reverse rotation operation at the start position specified by the start position specifying unit. Continuous execution means for continuously executing the drilling by the drilling means;
A frequency designating unit for designating a frequency of performing the reverse rotation operation by the reverse rotation unit when the continuous execution unit continuously executes the drilling by the drilling unit;
The numerical controller according to claim 1, wherein the reverse rotation unit performs the reverse rotation operation based on the frequency specified by the frequency specifying unit.   4. The rotation speed of the main shaft during the reverse rotation operation is at least equal to or lower than the rotation speed of the main shaft when the drilling unit executes the drilling. 5. Numerical control unit. A numerical value that controls the movement of the spindle head of a machine tool provided so as to be able to reciprocate in one direction opposite to the work table that supports the workpiece, and the rotation of the spindle that is rotatably supported by the spindle head and on which a tool is mounted. In the control method of the control device,
A drilling step in which the spindle head is moved in the predetermined direction while rotating the spindle in a predetermined direction, and the tool is brought into contact with the workpiece to make a hole; and
A moving step of moving the spindle head in the opposite direction from a position after the drilling by the drilling step toward a return point away from the workpiece;
In the moving step, a reverse rotation operation for rotating the main shaft in a direction opposite to the predetermined direction is started until the main shaft head moves in the opposite direction from the position after the drilling and reaches the return point. And a reverse rotation step. A control method for a numerical control device, comprising:

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