JP4487593B2 - Machine tool with drilling function - Google Patents

Description

  The present invention relates to a machine tool with a drilling function such as a turret lathe with a drill head or a drilling machine, and a drilling method using the machine tool.

Some turret lathes have a drill head installed on the turret as one of the tools. In drilling in a lathe, a hole is made in the outer peripheral surface of a round bar-shaped workpiece, and therefore when the drilling comes into contact with the workpiece, the tip of the drilling may be warped from the center. If processing is continued as it is, breakage of the drill will occur.
For this reason, measures such as reducing the moving speed of the drill head according to the machining program immediately after the drill cutting comes into contact with the workpiece and increasing the cutting speed after machining to a certain depth are taken.

In addition, in the drilling machine, immediately after the surface of the workpiece is struck by the tip of the drill cutting that rotates at a high speed so that a hollow center hole (preparation hole) is formed on the workpiece surface by the collision, There has been proposed a method in which the contact pressure is once relaxed, and then the drilling is continued by increasing the contact pressure with respect to the workpiece for drilling (for example, Patent Document 1).
Japanese Patent No. 2642797

In order to change the speed during the machining as in the conventional lathe, it is necessary to determine the speed change position in the machining program, and it is difficult to set an appropriate speed change position. In addition, the approach distance becomes low, and the low speed range is set longer in anticipation of safety so that the workpiece does not collide, so that the cycle time becomes longer.
As shown in Patent Document 1, even if the center hole is formed, the center hole is formed by collision while rotating at a high speed. When drilling a curved surface or a slope, a drill is performed when the center hole is formed. There is a risk that the cut may be bent and breakage may occur.

The object of the present invention is to provide a machine with a drilling function that is excellent in preventing breakage in drill cutting, can automatically detect the high / low speed switching timing for preventing breakage, and can reduce the machining time by reducing the low-speed movement area of the drill. Is to provide a machine.
Another object of the present invention is to ensure that machining can be performed reliably and the machining time is shortened as much as possible even in a cycle for detecting a position for switching between high and low speeds.
Still another object of the present invention is to provide a method of use capable of preventing slippage in an environment where drill cutting is slippery.

The machine tool with a drilling function according to the present invention includes a drill head (4) for rotating a drilling cutter (3), and a tool for moving the drill head (4) relative to a workpiece (W) at a predetermined position. A machine body (1) having an advance / retreat mechanism (5) and a control device (2) for controlling the rotation of the drill head (4) and the advance / retreat of the tool advance / retreat mechanism (5).
The control device (2) includes an initial machining control means (23) for controlling the first operation when machining a plurality of workpieces (W) repeatedly, and a repeated machining control means (24) for controlling the operation from the second time. ). The initial machining control means (23) moves the drill cutting (3) in the axial direction in a rotation stopped state and presses it against the work (W), which is the center position in the axial direction when a predetermined pressing force is reached. The hole completion position (P3) is stored. The repetitive machining control means (24) cuts from the predetermined position (P1) in the vicinity of the workpiece (W) to at least the center hole completed position (P3) when the drill cutting (3) is moved in the axial direction while rotating. When the center hole completion position (P3) or the position advanced by a predetermined amount from the center hole completion position (P3) is reached, it is moved at the cutting feed speed.

According to this configuration, the first workpiece (W) is pressed against the workpiece (W) by moving the drill cutting (3) in the axial direction in a rotation stopped state under the control of the initial machining control means (23). The center hole completion position (P3), which is the axial position when the pressing force is applied, is stored. At the time of this pressing, since the rotation of the drilling (3) is stopped and the feed is performed at a low speed, there is no risk of breakage.
For the second and subsequent workpieces (W), the drilling (3) is controlled from the predetermined position (P1) near the workpiece (W) to the center hole completion position (P3) by the control of the repetitive machining control means (24). Is moved in the axial direction while rotating the drill cutter (3) at a low speed lower than the cutting feed speed, and reaches a position advanced by a predetermined amount from the center hole completion position (P3) or the center hole completion position (P3). Move at cutting feed rate. In this case, after the center hole is formed in the workpiece (W) by moving at a low speed, the machining is continued at the cutting feed speed. Therefore, even if the surface of the workpiece (W) is a curved surface or a slope, drill cutting (3 ) Is warped and no excessive load is applied, and breakage can be prevented.

  Thus, the center hole completion position (P3) is detected at the time of processing the first workpiece (W), and from the second time, the center hole is moved at a low speed from the workpiece vicinity position (P1) to the center hole completion position (P3). Since the machining is continued as the cutting feed speed after forming the drill, the machining time, that is, the cycle time is shortened by reducing the low-speed movement area of the drill cutting (3) without causing the problem of breakage of the drill cutting (3). can do. In addition, since the center hole completion position (P3) in the first workpiece (W) is detected as the center hole completion position (P3), the axial position when the predetermined pressing force is reached is stored. The center hole completion position (P3) giving the switching timing can be automatically detected. In this case, since the drilling (3) is pressed against the workpiece (W) in a rotation stopped state, the drilling (3) is hardly broken.

In this invention, after the center hole completion position (P3) is memorized by the initial machining control means (23) for the first workpiece (W), various forms can be adopted to continue the hole machining. It is preferable to process as described above.
For example, the initial machining control means (23) moves the drilling (3) in the axial direction in a rotation stopped state and presses it against the workpiece (W), the torque of the advance / retreat operation of the tool advance / retreat mechanism (5). Alternatively, a center hole completion position detection unit (P3) that detects that the position deviation has reached a set value corresponding to the predetermined pressing force and stores the center hole completion position (P3) that is the axial position at the time of detection. 25), and after detecting the center hole completion position (P3), the drill cutting (3) is returned to the torque increase start position (P2) which is the position when the torque or the position deviation starts to increase. It is good also as having a post-detection process control part (26) which rotates a drill cutting (3) and processes with a cutting feed rate.
In this way, the first time, since the drilling (3) is once returned after the processing, the drilling (3) can be surely drilled without causing the problem of breakage of the drilling (3). Since the return position (P2) is a position where the torque or position deviation at the start of pressing starts to increase, the biting of the drilling (3) can be reliably eliminated, and the drilling (3) ), A shorter return distance is required than when moving to a point farther away, and an increase in machining time is mitigated. For this reason, even if it is the cycle which detects the position for high-low speed switching, processing can be performed reliably and processing time can be shortened as much as possible.

In the drilling method of the present invention, the drilling (3) is moved relative to the workpiece (W) in the axial direction, and a drilling process is performed on a curved surface or an inclined surface inclined with respect to the axial direction of the workpiece (W). A way to
When machining the first workpiece (3), the drilling (3) is moved in a rotation stopped state and pressed against the workpiece (W), and the center hole is the axial position when the predetermined pressing force is reached. The completed position (P3) is memorized and drilled,
When machining the second and subsequent workpieces (W), the drill cutting (3) is rotated, and at least from the predetermined position (P1) near the workpiece to the center hole completion position (P3) than the cutting feed rate. It is moved at a low speed, and when it reaches the center hole completion position (P3) or a position advanced by a predetermined amount from the center hole completion position (P3), it is moved at a cutting feed speed for drilling.
When drilling a curved surface or an inclined surface portion, the drill cutting (3) is in a state where it is slippery. In such a situation, as in the machine tool with a drilling function of the present invention, breakage is caused. Advantages of prevention, automatic detection of high / low speed switching timing, and shortening of machining time are effectively exhibited.

The machine tool with a drilling function of the present invention has an initial machining control means for controlling the first operation when machining a plurality of workpieces repeatedly, and a repeated machining control means for controlling the operation from the second time. The initial machining control means is configured to store the center hole completion position which is the axial position when the drill cutting is moved in the axial direction in a rotation stopped state and pressed against the workpiece, and when a predetermined pressing force is reached, The repetitive machining control means moves the shaft in the axial direction at a speed lower than the cutting feed speed from a predetermined position near the workpiece to at least the center hole completion position when moving in the axial direction while rotating the drill cutting. When reaching a hole completion position or a position advanced by a predetermined amount from the center hole completion position, it is moved at the cutting feed speed. The high and low speed switching timing for preventing breakage can be detected automatically, the effect is obtained that the low-speed movement region of the drill small to be shortened machining time.
Torque or position deviation of the advance / retreat operation of the tool advance / retreat mechanism when the initial machining control means is pressed against the workpiece by moving the drill cutting in the axial direction in a rotation stopped state corresponds to the predetermined pushing force. A center hole completion position detection unit that detects that the set value has been reached and stores the center hole completion position that is the axial position at the time of detection, and after detecting the center hole completion position, If it has a post-detection processing control unit that returns to the torque increase start position, which is the position when the position deviation starts to increase, and then rotates the drill cutting and performs processing at the cutting feed rate, high and low speed Even in a cycle in which the position for switching is detected, machining can be performed reliably and the machining time can be shortened as much as possible.

  The drilling method of the present invention is a method of drilling a curved surface or an inclined surface inclined with respect to the axial direction of the workpiece by relatively moving the drilling in the axial direction with respect to the workpiece. When drilling, the drill cutting is moved in a rotation stopped state and pressed against the workpiece, the center hole completion position which is the axial position when the predetermined pressing force is reached is memorized, and drilling is performed, When machining the second and subsequent workpieces, the workpiece is moved at a speed lower than the cutting feed speed from a predetermined position in the vicinity of the workpiece to at least the center hole completion position while rotating the drill cutting. Since it is a method of drilling by moving at a cutting feed rate when it reaches a position advanced by a predetermined amount from the center hole completion position, such an environment where drill cutting is easy to slide In the same way as the machine tool with a drilling function of the present invention, the effects of breakage prevention, automatic detection of high / low speed switching timing, and shortening of the machining time can be obtained. When using the machine tool with a drilling function of the present invention, The power can be demonstrated effectively.

  An embodiment of the present invention will be described with reference to the drawings. The machine tool with a drilling function includes a machine main body 1 and a control device 2 that controls the machine main body 1. The machine main body 1 includes a drill head 4 that rotates the drill cutter 3 and a tool advance / retreat mechanism 5 that advances and retracts the drill head 4 relative to the workpiece W supported at a predetermined position. The machine body 1 may be a drilling machine or the like dedicated to drilling, but in this embodiment is a turret type lathe.

As shown in FIGS. 6 and 7, the machine main body 1 including the turret type lathe includes a main shaft 6 that supports and rotates a work W at a predetermined position, and a turret 7 on which a drill head 4 is mounted. . The main shaft 6 is installed on a main shaft base 9 on the bed 8, and a main shaft motor (not shown) that rotates the main shaft 6 can index the rotation angle of the main shaft 6 to a desired position.
The turret 7 is installed on the feed base 10 in a posture in which the center of the turret is parallel to the main shaft 6, and the drill head 4 is installed at any one of a plurality of tool stations S on the outer peripheral surface. Other tool stations S are provided with tools 11 such as tools. The feed base 10 is installed on the bed 8 via a guide 12 so as to be movable in the left-right direction (X-axis direction), which is the radial direction with respect to the main shaft 6, and is driven forward and backward by the tool advance / retreat mechanism 5. The tool advance / retreat mechanism 5 includes a ball screw 13 and a servo motor 14, and the servo motor 14 has a position detector 15 such as an encoder.

  The turret 7 is installed on the feed base 10 so as to be movable back and forth in the front-rear direction (Z-axis direction) perpendicular to the advance / retreat direction (X-axis direction) and to be indexed and rotated around the center of the turret. The turret 7 is moved back and forth by a back and forth moving mechanism 16 including a servo motor and a ball screw. The indexing rotation of the turret 7 is performed by an indexing rotation mechanism 17 composed of a servo motor and gears.

  In FIG. 1, a control device 2 is a device that controls the entire machine body 1, and includes a computer-type numerical control device (NC) and a programmable controller (PC). The control device 2 controls the machine body 1 by executing the machining program 21 with the arithmetic control unit 22. The arithmetic control unit 22 includes a central processing unit (CPU) and a memory, a control program, and the like, and has means for decoding the machining program 21 described by NC code or the like. In the following description, the control of the rotation of the drill head 4 and the advance / retreat of the tool advance / retreat mechanism 5 will be described, and the description of the control of other parts of the machine body 1 will be omitted.

The arithmetic control unit 22 causes the drill rotation control unit 27 and the tool advance / retreat axis control unit 28 to execute the command according to the type of the command obtained by decoding the machining program 21.
The drill rotation control unit 27 is a means for outputting a rotation command and a stop command to the drill head 4 in accordance with a drill rotation command (not shown) in the machining program 21.
The tool advance / retreat axis control unit 28 is a means for giving a command to the servo control unit 29 in accordance with a movement command in the X-axis direction in the machining program 21.

  The servo control unit 29 is of a feedback type, and gives the servo motor 14 an output corresponding to the command position given from the tool advance / retreat axis control unit 28 and the position deviation obtained from the position detector 16 of the servo motor 14. . A torque detection means 31 is provided in the servo control unit 29 or in a system for supplying a drive current from the servo control unit 29 to the servo motor 14. The torque detection means 31 may be one that detects a torque value, or may be an ammeter that indirectly detects torque based on a current value or the like.

  In such a basic configuration, the control device 2 has a first machining control means 23 for controlling the first operation when a plurality of workpieces having the same shape are repeatedly machined, and a repeated machining for controlling the operation from the second time. And control means 24. Each of the initial machining control means 23 and the repetitive machining control means 24 is configured by an instruction provided in the machining program 21 and the hardware of the control device 2 that executes the instruction, but the hardware configuration is general. FIG. 1 shows a block diagram in the machining program 21 which is a characteristic part.

The initial machining control means 23 moves the drilling 3 in the axial direction in a rotation stopped state and presses it against the workpiece W, and stores a center hole completion position P3 that is an axial position when a predetermined pressing force is reached. Means.
The repetitive machining control means 24 rotates the drill cutter 3 from a predetermined position P1 in the vicinity of the work W that is the approach position to the center hole completion position P3 while rotating the drill cutter 3 at a low speed lower than the cutting feed speed. When the center hole completion position P3 is reached, the cutting feed speed is increased. The position to be changed to the cutting feed speed may be a position advanced by a predetermined amount from the center hole completion position P3. This predetermined amount is appropriately set in the repetitive machining control means 24.

The initial machining control means 23 includes a center hole completion position detection unit 25 and a post-detection machining control unit 26.
The center hole completion position detection unit 25 determines whether the torque or position deviation of the advance / retreat operation of the tool advance / retreat mechanism 5 when the drill notch 3 is moved in the axial direction in a rotation stopped state and pressed against the work W is the predetermined push It is means for detecting that the set value corresponding to the contact force has been reached, and storing the center hole completion position P3 which is the axial position at the time of detection in the storage means 30.
After detecting the center hole completion position P3, the post-detection processing control unit 26 returns the drill notch 3 to the torque increase start position P2, which is the position when the torque or position deviation starts to increase, and then the drill notch 3 is returned. It is means for rotating and machining at a cutting feed rate.

  The initial machining control means 23 and the repetitive machining control means 24 are means for performing the control respectively shown in the flowcharts in FIGS. 2 and 3, and the details will be described together with the following description of the operation.

The operation of the above configuration will be described. When a plurality of workpieces having the same shape are repeatedly drilled, the first one is controlled by the initial machining control means 23 as shown in the flowchart of FIG.
In the machining program 21, if there is a drilling command, the drill head 4 located at a predetermined standby position away from the spindle 6 is driven by the tool advance / retreat mechanism 5 together with the feed base 10 and the turret 7, and the tip of the drill cutting 3. Is fast-forwarded until it reaches a predetermined approach position P1 (step S1 in FIG. 2). This movement is performed while the rotation of the drilling machine 3 is stopped. The approach position P1 is, for example, a proximity position that is a predetermined distance away from the surface of the workpiece W, and is appropriately set by the machining program 21 according to the workpiece diameter or the like.

  When the approach position P1 is reached, it is moved at the cutting feed speed while the rotation of the drilling 3 is stopped (S2). When the tip of the drilling 3 comes into contact with the surface of the workpiece W due to this movement, the torque value of the servo motor 14 of the tool advance / retreat mechanism 5 starts to increase due to the resistance, and the position deviation also starts to increase. This torque value or position deviation increase start position P2 (FIG. 1) is stored in a predetermined storage means (S3), and the above movement is continued. An increase in torque value can be detected by the torque detector 31, and an increase in position deviation can be detected by the servo control unit 29. As the position at that time, for example, a detection value of the position detector 16 is used.

  The center hole completion position detector 25 in FIG. 1 monitors this torque value or position deviation (step S4 in FIG. 2), and when the torque value or position deviation becomes a set value, the center hole that is the axial position at this time The completion position P3 is stored in the center hole completion position storage means 30 (FIG. 1) (S5), and the tool advancement / retraction mechanism 5 is reversely rotated to retract the drill cutter 3 (S6). After the center hole (not shown) is formed in this way, the drilling 3 is retracted. When the drill notch 3 returns to the previously stored torque increase start position (or position deviation increase start position) P2, the drill notch 3 is moved in the cutting direction while rotating and drilled to the target depth position (S7). . This movement is performed at the cutting feed rate. When the drilling is completed to the target depth position, the drilling 3 is moved backward. In this way, the first processing is completed.

The second and subsequent workpieces W are performed as shown in the flowchart of FIG. 3 by the repetitive machining control means 24 of FIG. Similarly to the above, fast-forwarding is performed from the standby position to the approach position P1 while the drilling 3 is stopped (step Q1 in FIG. 3). FIG. 4 is a graph showing the moving speed of the drilling 2 for the second and subsequent workpieces W, and the timing indicated by (P1) in FIG. 4 is the time when the approach position P1 is reached.
When the approach position P1 is reached, the drill cutting 3 starts to rotate and moves at a speed U2 slower than the cutting feed speed U0 (Q2). This movement is performed up to the center hole completion position P3 stored for the first time (Q3). A center hole (not shown) is formed in the workpiece W by the low-speed movement while rotating. The speed control of the low-speed movement is performed, for example, by applying a speed override of about several tens of percent to the cutting feed speed U0.

  After moving to the center hole completion position P3, the drilling is performed to the target depth as the cutting feed speed by setting the speed override to 100% (Q4).

According to the machine tool with the drilling function of this configuration, the center hole completion position P3 is detected at the time of machining the first workpiece W in this way, and from the second time, the workpiece moves at a low speed from the workpiece vicinity position P1 to the center hole completion position P3. Since the machining is continued as the cutting feed speed after forming the center hole, the machining time can be shortened by reducing the low-speed moving region of the drilling 3 without causing the problem of breakage of the drilling 3. .
Further, the center hole completion position P3 of the first workpiece W is detected by moving the drill notch 3 in the axial direction with the rotation stopped and pressing the workpiece 3 against the workpiece W to determine the axial position when the predetermined pressing force is reached. Since the center hole completion position P3 is stored, the center hole completion position P3 giving the high / low speed switching timing can be automatically detected. At this time, since the drilling 3 is pressed against the workpiece W in a rotation stopped state, the drilling 3 is hardly broken.

  In addition, since the processing is performed after the drilling 3 is once returned for the first time, the drilling can be surely performed without causing the problem of breakage of the drilling 3 in the first time. Since the return position P2 is a position where the torque or position deviation at the start of pressing starts to increase, the biting of the drilling 3 can be reliably eliminated, and the drilling 3 is moved until it moves away from the workpiece W. However, a short return distance is sufficient, and the increase in processing time is mitigated. For this reason, even if it is the cycle which detects the position for high-low speed switching, processing can be performed reliably and processing time can be shortened as much as possible.

  In the above processing example, the work W has a round bar shape and the drilling is performed toward the axial center. However, the machine tool with the drilling function is, for example, as shown in FIG. The advantages are further exhibited. That is, when drilling a curved surface or an inclined surface portion in which the normal line L of the drilling contact point Wp of the workpiece W is inclined with respect to the drilling direction Wx, drilling is performed using the machine tool with the drilling function. Do. In this case, because of the curved surface and the inclination, the drilling 3 is easy to slip, and the drilling 3 is likely to break in normal processing. However, by using this machine tool with a drilling function, slip prevention can be achieved. It is possible to obtain the excellent breakage prevention performance of the drilling 3. Moreover, the high / low speed switching timing for preventing breakage can be automatically detected, and the machining time can be shortened by reducing the low speed movement region of the drill.

  Examples of the workpiece surface inclined at the drilling contact point Wp with respect to the drilling direction Wx include machining the eccentric shaft portion Wa of the workpiece W as shown in FIG. There may be a case where a hole is formed obliquely with respect to the formed flat portion (not shown). In addition to this, there is a case in which drilling is performed at an eccentric position of the round bar workpiece W using a machine body having a function of moving the drill head 4 up and down (Y-axis direction) with respect to the main shaft 6 (FIG. 1). is there.

It is a block diagram which shows the conceptual structure of the machine tool with a drilling function concerning one Embodiment of this invention. It is a flowchart which shows the control of the first process control means. It is a flowchart which shows control of the repetition process control means. It is explanatory drawing of the speed pattern at the time of repeated processing. It is explanatory drawing of one form of the relationship between a workpiece | work and drill cutting. It is a front view of a machine body. It is a top view of a machine body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Machine main body 2 ... Control apparatus 3 ... Drill cutting 4 ... Drill head 5 ... Tool advance / retreat mechanism 6 ... Spindle 7 ... Turret 14 ... Servo motor 15 ... Position detector 16 ... Front-back moving mechanism 21 ... Machining program 23 ... Initial machining control Means 24 ... repetitive machining control means 25 ... center hole completion position detection section 26 ... post-detection machining control section 29 ... servo control section 31 ... torque detection means P1 ... predetermined position (approach position)
P2: Torque increase start position P3: Center hole completion position

Claims (3)

Drill head for rotating drill cutting, machine main body having a tool advance / retreat mechanism for moving the drill head relative to a workpiece at a predetermined position, and a control device for controlling the rotation of the drill head and the advance / retreat of the tool advance / retreat mechanism A machine tool with a drilling function equipped with
The control device includes an initial machining control unit that controls an initial operation when machining a plurality of workpieces repeatedly, and a repeated machining control unit that controls an operation from a second time. , The drill cutting is moved in the axial direction in the rotation stopped state and pressed against the work, and the center hole completion position which is the axial position when the predetermined pressing force is reached is stored, and the repetitive machining control means When moving in the axial direction while rotating the drill cutting, the center hole is moved from a predetermined position near the workpiece to at least the center hole completion position at a speed lower than the cutting feed speed, and the center hole completion position or the center hole completion position is moved. A machine tool with a drilling function that moves at a cutting feed rate when a position advanced by a predetermined amount is reached.   In the first machining control means, the torque or position deviation of the advancing / retreating operation of the tool advancing / retreating mechanism when the drilling is moved in the axial direction in a rotation stopped state and pressed against the work corresponds to the predetermined pressing force. A center hole completion position detection unit that detects that the set value has been reached and stores the center hole completion position that is the axial position at the time of detection, and after detecting the center hole completion position, 2. A post-detection processing control unit that returns to a torque increase start position that is a position at which the position deviation starts to increase, and then rotates the drill cutting to perform processing at a cutting feed rate. Machine tool with drilling function. A method of drilling a curved surface or an inclined surface that is inclined with respect to the axial direction of the workpiece by relatively moving the drill cutting in the axial direction with respect to the workpiece,
When machining the first workpiece, move the drill cutter in a rotation stopped state and press it against the workpiece, memorize the center hole completion position which is the axial position when the predetermined pressing force is reached, and drill Processed
When machining the second and subsequent workpieces, the workpiece is moved at a speed lower than the cutting feed speed from a predetermined position in the vicinity of the workpiece to at least the center hole completion position while rotating the drill cutting. A drilling method in which a hole is drilled by moving at a cutting feed rate when a position advanced by a predetermined amount from the center hole completion position is reached.

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