Machine tool and control method for machine tool

Abstract

In machine tools, the condition of the workpiece is confirmed to be unsuitable for machining without visual inspection by the operator. [Solution] The control device performs a first control, which involves advancing the spindle with the chuck closed, and then moving the tool rest until the cutting tool reaches a predetermined contact position. After the first control, the control device moves the tool rest in a direction away from the predetermined contact position, then retracts the spindle in the axial direction of the workpiece with the chuck closed, and then performs a second control, which involves moving the tool rest again until the cutting tool reaches a predetermined contact position. The control device then determines that the condition of the workpiece is such that machining by the machine tool cannot begin if no contact between the cutting tool and the workpiece is detected in the first control, or if contact between the cutting tool and the workpiece is detected in both the first and second controls.

Description

Technical Field

[0001] The present invention relates to a machine tool and a control method for a machine tool.

Background Art

[0002] Conventionally, a machine tool that processes a bar-shaped workpiece held by a chuck of a spindle with a tool is known. In such a machine tool, at the spindle, the workpiece is held by the chuck with the end portion on the machining target side of the workpiece protruding. Then, the workpiece is machined by bringing a tool provided on a tool post into contact with a portion of the workpiece protruding from the spindle.

[0003] Further, Patent Document 1 discloses a technique related to a bar material processing machine provided with a bar material automatic feeder. In the technique disclosed in Patent Document 1, whether or not the remaining portion (remaining material) of a bar material that has been subjected to predetermined machining by the bar material processing machine has been carried away by the feed bar of the bar material automatic feeder is confirmed by a remaining material detection mechanism. Here, the feed bar of the bar material automatic feeder has a function of gripping the bar material by a finger chuck. The remaining material detection mechanism determines whether or not the remaining material has been carried away by the feed bar based on whether or not the remaining material is detected by a sensing mechanism within the movement trajectory through which the remaining material gripped by the feed bar passes when the position of the feed bar is displaced between a position inside and a position outside the guide rail of the bar material automatic feeder.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In machine tools that process a rod-shaped workpiece held by a chuck on the spindle using a cutting tool, multiple machining operations may be performed on a single workpiece. When multiple machining operations are performed on a single workpiece, once one machining operation is complete, the chuck on the spindle is temporarily released, and the workpiece is pushed out in the direction it is protruding from the spindle. Then, the chuck on the spindle is closed, and the workpiece is held again by the chuck with the end of the workpiece being machined protruding from the spindle. The next machining operation is then performed on the workpiece.

[0006] In some cases, the machine tool may not be equipped with a material feeder that automatically supplies workpieces to the machine tool (for example, the automatic bar material feeder described in Patent Document 1 above). In such machine tools that are not equipped with a material feeder, during the series of processes from the completion of one machining operation to the start of the next, when the chuck is opened and the workpiece is pushed out in the direction protruding from the spindle, and then the chuck is closed, it is generally the operator of the machine tool who visually confirms whether the workpiece is actually held by the chuck.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a technology that allows for the confirmation, without visual inspection by the operator, that the condition of the workpiece is such that it is impossible to start machining with the cutting tool, in a machine tool that processes a rod-shaped workpiece with a cutting tool. [Means for solving the problem]

[0008] A machine tool according to a first aspect of the present invention has a rod-shaped workpiece with the end on the side to be machined protruding. A machine tool comprising: a spindle held by a chuck in a closed state; a tool holder provided with a cutting tool for machining a portion of the workpiece protruding from the spindle; a predetermined contact position where the cutting tool and the workpiece come into contact when the workpiece is machined by the cutting tool on the tool holder; a guide bush supporting the workpiece between the spindle and the chuck; detection means for detecting when the cutting tool on the tool holder comes into contact with the workpiece at the predetermined contact position; and a control device for controlling the spindle and the tool holder, wherein the control device includes a first control that moves the spindle forward a first predetermined distance in the axial direction of the workpiece with the chuck closed, and then moves the tool holder until the cutting tool reaches the predetermined contact position; After the execution of the first control, the tool holder is moved in a direction away from the predetermined contact position, the spindle is moved back a second predetermined distance in the axial direction of the workpiece with the chuck closed, and then the tool holder is moved again until the tool reaches the predetermined contact position. If the detection means does not detect contact between the tool and the workpiece in the first control, or if the detection means detects contact between the tool and the workpiece in the first control and the detection means detects contact between the tool and the workpiece in the second control, it is determined that the state of the workpiece is such that machining by the machine tool cannot be started.

[0009] Furthermore, in a machine tool according to the first aspect of the present invention, the control device may determine that the state of the workpiece is in a state in which machining by the machine tool can begin if, in the first control, contact between the cutting tool and the workpiece is detected by the detection means, and in the second control, contact between the cutting tool and the workpiece is not detected by the detection means.

[0010] Furthermore, the machine tool according to the first aspect of the present invention may further include notification means for notifying that the control device has determined that the state of the workpiece is such that it is impossible to start machining by the machine tool.

[0011] Furthermore, in the machine tool according to the first aspect of the present invention, the detection means may include a touch sensor provided on the tool holder.

[0012] Furthermore, in a machine tool according to the first aspect of the present invention, the detection means may include a torque detection device that detects the torque of a motor that moves the tool holder.

[0013] Furthermore, a control method for a machine tool according to a second aspect of the present invention is a control method for a machine tool comprising: a spindle that holds a rod-shaped workpiece with the end facing the workpiece protruding outwards by a chuck; a tool holder provided with a cutting tool for machining the portion of the workpiece protruding from the spindle; a predetermined contact position where the cutting tool and the workpiece come into contact when the workpiece is machined by the cutting tool on the tool holder; a guide bush that supports the workpiece between the spindle and the chuck; and a detection means for detecting when the cutting tool on the tool holder comes into contact with the workpiece at the predetermined contact position, wherein the first step is to move the tool holder forward a first predetermined distance in the axial direction of the workpiece with the chuck closed, and then move the tool holder until the cutting tool reaches the predetermined contact position. The process includes: executing a step; after executing the first step, moving the tool holder in a direction away from the predetermined contact position, then retracting the spindle by a second predetermined distance in the axial direction of the workpiece with the chuck closed, and then moving the tool holder again until the tool reaches the predetermined contact position; and determining that the state of the workpiece is such that machining by the machine tool cannot be started if contact between the tool and the workpiece is not detected by the detection means in the first step, or if contact between the tool and the workpiece is detected by the detection means in the first step and contact between the tool and the workpiece is detected by the detection means in the second control.

[0014] Furthermore, a control method for a machine tool according to a second aspect of the present invention may further include determining that the state of the workpiece is in a state in which machining by the machine tool can begin, if contact between the cutting tool and the workpiece is detected by the detection means in the first step, and contact between the cutting tool and the workpiece is not detected by the detection means in the second control. [Effects of the Invention]

[0015] According to the present invention, in a machine tool that processes a rod-shaped workpiece with a cutting tool, it is possible to confirm, without visual inspection by the operator, that the condition of the workpiece is such that it is impossible to start processing by the machine tool. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic diagram illustrating the hardware configuration of a machine tool according to an embodiment. [Figure 2] Figure 2 is a schematic block diagram showing an example of the functional configuration of a machine tool according to this embodiment. [Figure 3] Figure 3 is the first diagram showing the spindle mechanism, cutting tool mechanism, and workpiece when the verification process is performed in the machine tool. [Figure 4] Figure 4 is a second diagram showing the state of the spindle mechanism, cutting tool mechanism, and workpiece when the verification process is performed in the machine tool. [Figure 5] Figure 5 is a third diagram showing the spindle mechanism, cutting tool mechanism, and workpiece when the verification process is performed in the machine tool. [Figure 6] Figure 6 is the fourth diagram showing the spindle mechanism, cutting tool mechanism, and workpiece when the verification process is performed in the machine tool. [Figure 7] Figure 7 is the fifth diagram showing the spindle mechanism, cutting tool mechanism, and workpiece when the verification process is performed in the machine tool. [Figure 8] Figure 8 is a flowchart showing the flow of the verification process.

Best Mode for Carrying Out the Invention

[0017] Hereinafter, specific embodiments of the present invention will be described based on the drawings. The dimensions, materials, shapes, and relative arrangements of the components described in this embodiment are not intended to limit the technical scope of the invention only to these, unless otherwise specified.

[0018] <Embodiment> (Schematic Configuration of Machine Tool) FIG. 1 is a schematic diagram schematically showing the hardware configuration of a machine tool according to an embodiment of the present invention. The machine tool 1 shown in FIG. 1 is a so-called automatic lathe device. The machine tool 1 has a function of performing turning on a bar-shaped workpiece W to be machined by a tool (bit).

[0019] As shown in FIG. 1, the machine tool 1 includes a spindle mechanism 100, a tool mechanism 300, and a control device 400. The machine tool 1 does not include a feeding device that automatically supplies the workpiece W to be machined to the spindle mechanism 100. Therefore, the workpiece W is manually supplied to the spindle mechanism 100 by an operator.

[0020] In the machine tool 1, the spindle mechanism 100 is disposed on the base 2. When the workpiece W is machined by the machine tool 1, the spindle mechanism 100 holds the workpiece W and rotates the workpiece W around its axis. The tool mechanism 300 is installed such that a tool can contact the workpiece W held by the spindle mechanism 100 when machining the workpiece W with the tool. The control device 400 controls the operations of the spindle mechanism 1 hundred and the tool mechanism 300. In FIG. 1, the axial direction of the workpiece W to be machined is taken as the Z-axis direction, and among the directions orthogonal to the axial direction of the workpiece W, the direction parallel to the vertical direction is taken as the X-axis direction. W's axial direction and orthogonal directions, the direction parallel to the vertical direction is the X-axis direction.

[0021] The spindle mechanism 100 includes a spindle 101, a headstock 102, and a headstock drive unit 103. A chuck 104 is also provided on the spindle 101. Furthermore, the spindle 101 of the spindle mechanism 100 has an axis extending in the direction of the Z-axis, which is the center of rotation.

[0022] In the spindle mechanism 100, the spindle 101 is supported on the headstock 102 so as to be rotatable around its axis. The headstock 102 is attached to the headstock drive unit 103. The headstock drive unit 103 has the function of moving the headstock 102, on which the spindle 101 is mounted, in the Z-axis direction on the base 2. The headstock drive unit 103 may, for example, employ a ball screw drive mechanism composed of a motor as a drive source, a ball screw, a guide rail, etc. Furthermore, the chuck 104 on the spindle 101 is configured to be openable and closable. When the chuck 104 is closed with the workpiece 4 inserted, the workpiece W is held by the chuck 104. As the workpiece W is held by the chuck 104, the workpiece W moves in the Z-axis direction along with the movement of the spindle 101 in the Z-axis direction. Furthermore, because the workpiece W is held by the chuck 104, the workpiece W rotates around the axis as the spindle 101 rotates around its axis.

[0023] In the spindle mechanism 100, the spindle 101 and the headstock 102 have through holes 100h that extend in the Z-axis direction along the axis. A workpiece W is inserted through these through holes 100h. More specifically, the workpiece W is inserted into the through holes 100h from the rear of the headstock 102 (opposite the installation position of the spindle 101). At this time, in order to make the end of the workpiece W on the workpiece side protrude from the front of the spindle 101, the operator feeds the workpiece W into the through holes 100h using a push rod, as shown in Figure 1. Then, with the end of the workpiece W on the workpiece side protruding from the front of the spindle 101, the chuck 104 is closed and the workpiece W is held by the chuck 104. As a result, with the end of the workpiece W on the workpiece side protruding from the spindle 101, the axis of the workpiece W on the spindle 101 is determined and the movement of only the workpiece W in the Z-axis direction is restricted.

[0024] Furthermore, in the machine tool 1, a guide bush 110 is provided in front of the spindle 101 of the spindle mechanism 100. The guide bush 110 supports the workpiece W that protrudes from the front of the spindle 101 of the spindle mechanism 100 so that it can rotate around its axis and slide in the Z-axis direction. Then, in the machine tool 1, the portion of the workpiece W that protrudes beyond the guide bush 110 (the front end) is turned by the cutting tool 302 of the cutting tool mechanism 300.

[0025] The cutting tool mechanism 300 comprises a cutting tool base 301, a cutting tool 302, and a touch sensor 303. In the cutting tool mechanism 300, the cutting tool base 301 is configured to move forward and backward (down or up) in the X-axis direction at a position forward of the guide bush 110 in the Z-axis direction. The cutting tool base 301 is also provided with a cutting tool 302 for machining the workpiece W. The cutting tool base 301 may be provided with multiple types of cutting tools that can be selected according to the type of machining to be performed. When the cutting tool base 301 moves (down) in the direction approaching the workpiece W in the X-axis direction, the cutting tool 302 contacts the end of the workpiece W on the machining side at a predetermined contact position. In other words, in the machine tool 1, the guide bush 110 supports the workpiece W between a predetermined contact position where the cutting tool 302 and the workpiece W come into contact when the workpiece W is machined by the cutting tool 302 of the cutting tool base 301, and the chuck 104 of the spindle 101 of the spindle mechanism 100. Then, the cutting tool 302 of the cutting tool mechanism 300 comes into contact with the workpiece W, which rotates around the axis with the spindle 101 while being held by the chuck 104 of the spindle mechanism 100 and supported by the guide bush 110, thereby performing a turning operation on the workpiece W.

[0026] Furthermore, in the cutting tool mechanism 300, a touch sensor 303 is provided on the cutting tool base 301. The touch sensor 303 is a sensor that detects contact when the cutting tool 302 comes into contact with the workpiece W as the cutting tool holder 301 moves in a direction approaching the workpiece W.

[0027] The control device 400 controls the operation of the spindle 101, the headstock drive unit 103, and the chuck 104 in the spindle mechanism 100, as well as the operation of the tool holder 301 in the tool mechanism 300. Your device 400 is comprised of a computer having a processor, main memory, auxiliary memory, input / output interface, and communication interface, etc.

[0028] Here, the processor is, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The main memory is, for example, RAM (Random Access Memory). The auxiliary memory is, for example, ROM (Read Only Memory), HDD (Hard Disk Drive), or flash memory. The auxiliary memory may also include removable media (portable recording media). Here, removable media is, for example, a USB memory stick, an SD card, or a disk recording medium such as a CD-ROM, DVD disc, or Blu-ray disc. The input / output interface is, for example, a touch panel display. The communication interface is, for example, a LAN (Local Area Network) interface board or a wireless communication circuit for wireless communication.

[0029] The auxiliary storage unit of the control device 400 stores the operating system (OS), various programs, and various information tables. The processor loads the programs stored in the auxiliary storage unit into the main storage unit and executes them, thereby realizing various processes such as confirmation processing to determine whether or not machining can be started by the machine tool 1, as described later. However, some or all of the functions of the control device 400 may be realized by hardware circuits such as ASICs or FPGAs. Furthermore, the control device 400 does not necessarily have to be realized by a single physical configuration, but may be composed of multiple computers that cooperate with each other.

[0030] (Functional Configuration) Next, the functional configuration of the machine tool 1 will be described based on Figure 2. Figure 2 is a schematic block diagram showing an example of the functional configuration of the machine tool 1 according to this embodiment. The spindle mechanism 100 includes a spindle motor 105 and a chuck actuator 106 in addition to the headstock drive unit 103. The spindle motor 105 is provided on the headstock 102 and is a servo motor (for example, a built-in motor) that rotates the spindle 101. The chuck actuator 106 is an actuator (for example, a hydraulic or air-operated actuator) that opens and closes the chuck 104.

[0031] The cutting tool mechanism 300 includes a cutting tool base drive unit 304 and a contact detection unit 310. The cutting tool base drive unit 304 has the function of moving (downward or upward) the cutting tool base 301 in the X-axis direction. The cutting tool base drive unit 304 may also have the function of moving the cutting tool base 301 not only in the X-axis direction, but also in the Z-axis direction and in a direction substantially perpendicular to the X-axis direction. The cutting tool base drive unit 304 may also employ a ball screw drive mechanism, similar to the headstock drive unit 103. The contact detection unit 310 has the function of detecting when the cutting tool 302 comes into contact with the workpiece W. The contact detection unit 310 is configured to include a touch sensor 303. In this embodiment, the contact detection unit 310 corresponds to the "detection means" according to the present invention.

[0032] The control device 400 controls the operation of the spindle mechanism 100 by transmitting control signals to the headstock drive unit 103, the spindle motor 105, and the chuck actuator 106 of the spindle mechanism 100. Specifically, the forward and backward driving of the headstock 102 by the headstock drive unit 103, the rotational driving of the spindle 101 by the spindle motor 105, and the opening and closing driving of the chuck 104 by the chuck actuator 106 are controlled by control signals transmitted from the control device 400.

[0033] Furthermore, the control device 400 controls the operation of the cutting tool mechanism 300 by transmitting control signals to the cutting tool base drive unit 304 of the cutting tool mechanism 300. Specifically, the downward or upward drive of the cutting tool base 301 by the cutting tool base drive unit 304 is controlled by the control signals transmitted from the control device 400. Also, if contact between the cutting tool 302 and the workpiece W is detected by the contact detection unit 310 of the cutting tool mechanism 300, a detection signal is transmitted from the contact detection unit 310 to the control device 400.

[0034] Furthermore, the control device 400 is equipped with a notification unit 410. The notification unit 410 has a function to notify the operator of alerts. The notification unit 410 may notify the operator of alerts by means of, for example, voice, light illumination, or display of text information. Details of alert notifications by the notification unit 410 will be described later.

[0035] (Verification process) Next, the confirmation process performed before the machining process for machining the workpiece W with the cutting tool 302 in the machine tool 1 will be explained based on Figures 3 to 7. When machining a single workpiece W multiple times is performed by the machine tool 1, after the completion of one machining pass, the workpiece W is pushed forward in the Z-axis direction (in the direction in which the workpiece W protrudes from the spindle 101) by the operator in the spindle mechanism 100. At this time, the chuck 104 in the spindle 101 of the spindle mechanism 100 is temporarily opened. Then, the operator inserts a push rod through the through hole 100h from the rear of the headstock 102 and pushes the workpiece W forward in the Z-axis direction with the inserted push rod. After that, the chuck 104 in the spindle 101 of the spindle mechanism 100 is closed again, so that the workpiece W is held by the chuck 104 with the end of the workpiece W that is to be machined protruding from the spindle 101.

[0036] However, the remaining length of the workpiece W may be shorter than the length anticipated by the operator. Therefore, when the operator pushes the workpiece W forward in the Z-axis direction using a push rod inserted through the through hole 100h from the rear of the headstock 102, the end of the workpiece W opposite to the end to be machined may also be pushed outside the spindle 101. In this case, the entire workpiece W is located outside the spindle 101, and even if the chuck 104 is closed again, the workpiece W cannot be held by the chuck 104. However, even if the workpiece W is not held by the chuck 104 of the spindle 101, the shortened workpiece W may be supported by the guide bush 110. However, if the workpiece W is not held by the chuck 104, it is not possible to machine the workpiece W with the cutting tool 302.

[0037] Therefore, in the machine tool 1 according to this embodiment, a confirmation process is performed before the machining process for machining the workpiece W is carried out. Here, the confirmation process is a process to confirm whether or not the workpiece W is actually held by the chuck 104 of the spindle 101, that is, whether or not the state of the workpiece W is such that machining by the cutting tool 302 can begin.

[0038] Figures 3 to 7 show the state of the spindle mechanism 100, the cutting tool mechanism 300, and the workpiece W when a verification process is performed on the machine tool 1. Figures 3 and 4 show the state when the verification process is performed when the workpiece W is in a normal state, i.e., in a state where machining by the cutting tool 302 can begin. Hereafter, the case shown in Figures 3 and 4 will be referred to as the first case. Figures 5 to 7 show the state when the verification process is performed when the workpiece W is in a state where machining by the cutting tool 302 cannot begin. Hereafter, the case shown in Figure 5 will be referred to as the second case, and the cases shown in Figures 6 and 7 will be referred to as the third case. In each of Figures 3 to 7, P0 is the position where the cutting tool 302 and the workpiece W come into contact. This indicates the designated contact position.

[0039] First, we will explain the first case based on Figures 3 and 4. Figure 3 is a diagram illustrating the first control in the verification process. Figure 4 is a diagram illustrating the second control executed after the first control in the verification process.

[0040] Figure 3(a) shows the first case, in which the operator pushes the workpiece W forward in the Z-axis direction using a push rod inserted through the through hole 100h from the rear of the spindle head 102. At this time, the chuck 104 on the spindle 101 is open. After the operator pushes the workpiece W with the push rod, the push rod is withdrawn from the through hole 100h.

[0041] Figures 3(b) and 3(c) show the state when the first control in the verification process is executed in the first case. After the workpiece W is pushed forward in the Z-axis direction in Figure 3(a), the chuck 104 of the spindle 101 is closed in the spindle mechanism 100. As a result, the workpiece W is held by the chuck 104. Then, in the first control of the verification process, first, as shown in Figure 3(b), with the chuck 104 closed in the spindle mechanism 100, the spindle head drive unit 103 drives the spindle head 102 forward in the direction of the white arrow A1, thereby advancing the spindle 101 by a predetermined distance L0. When the spindle 101 advances by the predetermined distance L0, the workpiece W held by the chuck 104 of the spindle 101 also advances by a predetermined distance L0. As a result, the portion of the workpiece W protruding from the spindle 101 is inserted into the guide bush 110 and reaches a predetermined contact position P0. Here, the predetermined distance L0 is the distance at which, if the remaining length of the workpiece W is sufficient and the workpiece W is held by the closed chuck 104, the spindle 101 will advance by a predetermined distance L0, causing the portion of the workpiece W protruding from the spindle 101 to reach a predetermined contact position P0.

[0042] In the first control of the confirmation process, as shown in Figure 3(c), the cutting tool mechanism 300 moves the cutting tool base 301 until the cutting tool 302 reaches a predetermined contact position P0 by driving the cutting tool base 301 downward in the direction of the white arrow A2 using the cutting tool base drive unit 304. As a result, as shown in Figure 3(c), the cutting tool 302 makes contact with the workpiece W at the predetermined contact position P0. At this time, the contact between the cutting tool 302 and the workpiece W is detected by the contact detection unit 310 of the cutting tool mechanism 300.

[0043] In the first control of the confirmation process, when the contact detection unit 310 detects contact between the cutting tool 302 and the workpiece W, the second control is then executed. Figures 4(a), (b), and (c) show the state when the second control in the confirmation process is executed in the first case. In the second control of the confirmation process, as shown in Figure 4(a), in the cutting tool mechanism 300, the cutting tool base drive unit 304 drives the cutting tool base 301 upward in the direction of the white arrow A3, thereby moving the cutting tool base 301 in a direction that moves the cutting tool 302 away from the predetermined contact position P0.

[0044] In the second control of the confirmation process, as shown in Figure 4(b), the spindle mechanism 100 is moved backward by a predetermined distance L0 by the spindle head drive unit 103 in the direction of the white arrow A4, with the chuck 104 closed. When the spindle 101 moves backward by the predetermined distance L0, the workpiece W held by the chuck 104 of the spindle 101 also moves backward by the predetermined distance L0. As a result, the portion of the workpiece W protruding from the spindle 101 moves away from the predetermined contact position P0 (the portion of the workpiece W protruding from the spindle 101 moves backward from the predetermined contact position P0).

[0045] In the second control of the confirmation process, as shown in Figure 4(c), the cutting tool mechanism 300 is then driven downward by the cutting tool base drive unit 304 in the direction of the white arrow A2. Then, the tool holder 301 is moved again until the cutting tool 302 reaches a predetermined contact position P0. At this time, the portion of the workpiece W that protrudes from the spindle 101 is set back from the predetermined contact position P0, so as shown in Figure 4(c), even when the cutting tool 302 reaches the predetermined contact position P0, the cutting tool 302 does not make contact with the workpiece W.

[0046] In addition, the distance traveled when the spindle 101 is retracted in the second control is not necessarily the same as the distance traveled when the spindle 101 is advanced in the first control. In other words, the distance traveled when the spindle 101 is retracted in the second control is sufficient if, with the workpiece W held by the closed chuck 104, the retraction of the spindle 101 causes the portion of the workpiece W protruding from the spindle 101 to move away from the predetermined contact position P0.

[0047] Next, the second case will be explained based on Figure 5. Figure 5 is a diagram illustrating the first control in the confirmation process. Figure 5(a) shows the situation in the second case when the operator pushes the workpiece W forward in the Z-axis direction using a push rod inserted through the through hole 100h from the rear of the headstock 102. Here, in the second case, the remaining length of the workpiece W is shorter than the remaining length of the workpiece W in the first case. As a result, when the operator pushes the workpiece W forward in the Z-axis direction with the push rod, as shown in Figure 5(a), the end of the workpiece W opposite to the end on the side to be machined is also pushed outside the spindle 101. As a result, the entire workpiece W is located outside the spindle 101. However, even in this case, the workpiece W is supported by the guide bush 110 by being inserted into the guide bush 110. On the other hand, the end of the workpiece W on the side to be machined has not reached the predetermined contact position P0.

[0048] Figures 5(b) and 5(c) show the state when the first control in the verification process is executed in the second case. In Figure 5(a), after the workpiece W is pushed forward in the Z-axis direction, the chuck 104 of the spindle 101 is closed again in the spindle mechanism 100. However, in the second case, even when the chuck 104 is closed, the workpiece W is not held by the chuck 104. Then, in the first control of the verification process, first, as shown in Figure 5(b), the spindle mechanism 100 moves the spindle 101 forward by a predetermined distance L0 by driving the spindle head 102 forward in the direction of the white arrow A1 by the spindle head drive unit 103 with the chuck 104 closed. At this time, the workpiece W is not held by the chuck 104, and even when the spindle 101 has moved forward by the predetermined distance L0, the workpiece W is not in contact with the chuck 104. Therefore, the position of the workpiece W is the same as the position before the first control was executed.

[0049] In the first control of the confirmation process, as shown in Figure 5(c), the tool mechanism 300 moves the tool base 301 until the tool 302 reaches a predetermined contact position P0 by driving the tool base drive unit 304 downward in the direction of the white arrow A2. At this time, in the second case, the position of the workpiece W is the same as before the first control was executed. That is, the end of the workpiece W on the side to be machined has not reached the predetermined contact position P0. Therefore, as shown in Figure 5(c), even if the tool 302 reaches the predetermined contact position P0, the tool 302 does not come into contact with the workpiece W. In other words, in the second case, when the confirmation process is executed, no contact occurs between the tool 302 and the workpiece W in the first control.

[0050] Next, the third case will be explained based on Figures 6 and 7. Figure 6 is a diagram illustrating the first control in the verification process. Figure 6(a) shows the situation in the third case when the operator pushes the workpiece W forward in the Z-axis direction using a push rod inserted through the through hole 100h from the rear of the headstock 102. Here, in the third case, the remaining length of the workpiece W is shorter than the remaining length of the workpiece W in the first case. Therefore, when the operator pushes the workpiece W forward in the Z-axis direction with the push rod, Figure 6( As shown in a), the end of the workpiece W opposite to the end being machined is pushed outside the spindle 101. As a result, similar to the second case, the entire workpiece W is located outside the spindle 101. Also, in this case, similar to the second case, the workpiece W is supported by the guide bush 110 by being inserted into the guide bush 110. On the other hand, the end of the workpiece W on the machined side does not reach the predetermined contact position P0. However, in the third case, the remaining length of the workpiece W is longer than the remaining length of the workpiece W in the second case.

[0051] Figures 6(b) and 6(c) show the state when the first control in the verification process is executed in the third case. In Figure 6(a), after the workpiece W is pushed forward in the Z-axis direction, the chuck 104 of the spindle 101 is closed again in the spindle mechanism 100. However, in the third case, as in the second case, the workpiece W is not held by the chuck 104 even when it is closed. Then, in the first control of the verification process, first, as shown in Figure 6(b), the spindle mechanism 100 moves the spindle 101 forward by a predetermined distance L0 by driving the spindle head 102 forward in the direction of the white arrow A1 using the spindle head drive unit 103, with the chuck 104 closed. At this time, although the workpiece W is not held by the chuck 104, when the spindle 101 moves forward by the predetermined distance L0, the end of the workpiece W opposite to the end on the side to be machined, which is supported by the guide bush 110, comes into contact with the front end face of the closed chuck 104. In this case, as the spindle 101 moves, the workpiece W also moves in the forward direction of the spindle 101 while in contact with the front end face of the chuck 104. As a result, as shown in Figure 6(b), the workpiece W, which is not held by the closed chuck 104, reaches a predetermined contact position P0.

[0052] In the first control of the confirmation process, as shown in Figure 6(c), the cutting tool mechanism 300 moves the cutting tool base 301 until the cutting tool 302 reaches a predetermined contact position P0 by driving the cutting tool base 301 downward in the direction of the white arrow A2 using the cutting tool base drive unit 304. At this time, in the third case, since the workpiece W has reached the predetermined contact position P0, the cutting tool 302 makes contact with the workpiece W at the predetermined contact position P0, as shown in Figure 6(c). At this time, the contact between the cutting tool 302 and the workpiece W is detected by the contact detection unit 310 of the cutting tool mechanism 300.

[0053] As described above, when contact between the cutting tool 302 and the workpiece W is detected in the first control of the confirmation process, the second control is then executed. Therefore, in the third case, as in the first case, the second control is executed after the first control is executed. Figures 7(a), (b), and (c) show the state when the second control in the confirmation process is executed in the third case. In the second control of the confirmation process, as shown in Figure 7(a), in the cutting tool mechanism 300, the cutting tool base drive unit 304 drives the cutting tool base 301 upward in the direction of the white arrow A3, thereby moving the cutting tool base 301 in a direction that moves the cutting tool 302 away from the predetermined contact position P0.

[0054] In the second control of the confirmation process, as shown in Figure 7(b), the spindle mechanism 100 is moved backward by a predetermined distance L0 by the spindle head drive unit 103, which drives the spindle head 102 backward in the direction of the white arrow A4, with the chuck 104 closed. At this time, since the workpiece W is not held by the chuck 104 of the spindle 101, even if the spindle 101 moves backward, the position of the workpiece W is the same as the position before the second control was executed. In other words, as shown in Figure 7(b), the state in which the workpiece W has reached the predetermined contact position P0 is maintained.

[0055] In the second control of the confirmation process, as shown in Figure 7(c), the tool mechanism 300 is driven downward by the tool base drive unit 304 in the direction of the white arrow A2, thereby moving the tool base 301 again until the tool 302 reaches a predetermined contact position P0. At this time, since the portion of the workpiece W that protrudes from the spindle 101 has reached the predetermined contact position P0, as shown in Figure 7(c), when the tool 302 reaches the predetermined contact position P0 the tool 302 The tool comes into contact with the workpiece W. At this time, the contact between the cutting tool 302 and the workpiece W is detected by the contact detection unit 310 of the cutting tool mechanism 300.

[0056] As described above, in the first case, where the workpiece W is in a state where machining with the cutting tool 302 can begin, when the confirmation process is executed, contact occurs between the cutting tool 302 and the workpiece W in the first control, and no contact occurs between the cutting tool 302 and the workpiece W in the second control. On the other hand, in the second case, where the workpiece W is in a state where machining with the cutting tool 302 cannot begin, when the confirmation process is executed, no contact occurs between the cutting tool 302 and the workpiece W in the first control. Furthermore, in the third case, where the workpiece W is in a state where machining with the cutting tool 302 cannot begin, when the confirmation process is executed, contact occurs between the cutting tool 302 and the workpiece W in the first control, and also in the second control.

[0057] Therefore, in the first and second control of the confirmation process, it is possible to determine whether the state of the workpiece W is such that machining by the cutting tool 302 can begin, based on whether or not contact between the cutting tool 302 and the workpiece W is detected by the contact detection unit 310.

[0058] (Confirmation process flow) Next, the flow of the verification process according to this embodiment will be described with reference to Figure 8. Figure 8 is a flowchart of the verification process according to this embodiment. This flow is executed by the control device 400 after the operator pushes the workpiece W forward in the Z-axis direction using a push rod inserted through the through hole 100h from the rear of the spindle head 102 of the spindle mechanism 100.

[0059] In this flow, first, in S101, the chuck 104 is closed on the spindle 101 of the spindle mechanism 100. Next, in S102, the spindle 101 is moved (forward) a predetermined distance L0 by driving the headstock 102 forward by the headstock drive unit 103 of the spindle mechanism 100. Next, in S103, the cutting tool 302 is moved to a predetermined contact position P0 by driving the cutting tool base 301 downward by the cutting tool base drive unit 304 of the cutting tool mechanism 300. Next, in S104, it is determined whether or not contact between the cutting tool 302 and the workpiece W has been detected by the contact detection unit 310 of the cutting tool mechanism 300. The steps from S101 to S104 in this flow constitute the first control of the confirmation process. Furthermore, the steps from S101 to S104 in this flow correspond to the "first step" according to the present invention.

[0060] If a negative result is obtained in S104, that is, if contact between the cutting tool 302 and the workpiece W is not detected in the first control, it can be determined that the workpiece W is not being held by the chuck 104 of the spindle 101, as in the second case described above. Therefore, in this case, it is determined that the state of the workpiece W is such that machining by the cutting tool 302 cannot be started, and the machining process for the workpiece W is not executed, and the process in S110 is then executed. In S110, an alert is sent to the operator via the notification unit 410 informing them that the state of the workpiece W is such that machining by the cutting tool 302 cannot be started. Then, the execution of this flow is terminated.

[0061] On the other hand, if a positive determination is made in S104, that is, if contact between the cutting tool 302 and the workpiece W is detected in the first control, the process in S105 is then executed. In S105, the cutting tool base 301 is driven upward by the cutting tool base drive unit 304 of the cutting tool mechanism 300, so that the cutting tool 302 is separated from the predetermined contact position P0. Next, in S106, the spindle 101 is moved a predetermined distance L0 (retracted) by the spindle base drive unit 103 of the spindle mechanism 100, so that the spindle 101 is driven backward. Next, in S107, the cutting tool base 301 is driven downward by the cutting tool base drive unit 304 of the cutting tool mechanism 300, so that the cutting tool 302 is moved back to the predetermined contact position P0. Next, in S108, contact between the cutting tool 302 and the workpiece W is detected by the cutting tool mechanism 3 It is determined whether or not the contact detection unit 310 of 00 has detected anything. Steps S105 to S108 in this flow are the second control of the confirmation process. Steps S105 to S108 in this flow correspond to the "second step" according to the present invention.

[0062] If a positive determination is made in S108, that is, if contact between the cutting tool 302 and the workpiece W is detected in the second control, it can be determined that the workpiece W is not being held by the chuck 104 of the spindle 101, as in the third case described above. Therefore, in this case, it is determined that the state of the workpiece W is such that machining by the cutting tool 302 cannot begin, and the machining process for the workpiece W is not executed, and the process in S110 is executed next. In other words, an alert is notified to the operator via the notification unit 410.

[0063] On the other hand, if a negative determination is made in S108, that is, if contact between the cutting tool 302 and the workpiece W is not detected in the second control, it can be determined that the workpiece W is being held by the chuck 104 of the spindle 101, as in the first case described above. In this case, the process in S109 is then executed. In S109, it is determined that the state of the workpiece W is such that machining by the cutting tool 302 can begin, and the machining process for machining the workpiece W is started. Then, the execution of this flow is completed. In this embodiment, the process in S109 in this flow corresponds to "determining that the state of the workpiece is such that machining by the machine tool can begin" according to the present invention.

[0064] According to the verification process described above, in a machine tool 1 that processes a rod-shaped workpiece W with a cutting tool 302, it is possible to confirm, without visual inspection by the operator, that the condition of the workpiece W is such that it is impossible to start processing by the machine tool 1.

[0065] In the above embodiment, the contact detection unit 310, which detects contact between the cutting tool 302 and the workpiece W, is configured to include a touch sensor 303 provided on the cutting tool base 301. However, the configuration of the contact detection unit 310 is not limited to this. For example, the cutting tool mechanism 300 may include a torque detection device that detects the torque of the motor, which is the drive source for the cutting tool base drive unit 304. In this case, contact between the cutting tool 302 and the workpiece W can be detected by referring to the change in torque detected by the torque detection device. Therefore, the contact detection unit 310 may be configured to include a torque detection device that detects the torque of the motor of the cutting tool base drive unit 304 instead of the touch sensor 303.

[0066] <Other Embodiments> The embodiments described above are merely examples, and this disclosure may be modified as appropriate without departing from its essence. Furthermore, the processes and means described in this disclosure can be freely combined and implemented as long as no technical inconsistencies arise.

[0067] Furthermore, a process described as being performed by a single device may be divided and executed by multiple devices. Conversely, a process described as being performed by different devices may be executed by a single device. In a computer system, the hardware configuration used to implement each function can be flexibly changed. [Explanation of Symbols]

[0068] 1...Machine tool, 100...Spindle mechanism, 101...Spindle, 102...Headstock, 103...Headstock drive unit, 104...Chuck, 105...Spindle motor, 106...Chuck actuator, 300...Cutting tool mechanism, 301...Cutting tool holder, 302...Cutting tool, 303...Touch sensor, 304...Cutting tool holder drive unit, 310...Contact detection unit, 400...Control device, 410...Notification unit

Claims

1. A spindle that holds a rod-shaped workpiece with the end facing the workpiece protruding using a chuck, A tool holder is provided with a cutting tool for machining the portion of the workpiece that protrudes from the spindle, A guide bush that supports the workpiece between the cutting tool on the cutting tool holder and the chuck of the spindle, where the cutting tool and the workpiece come into contact when the workpiece is machined by the cutting tool on the cutting tool holder and the chuck of the spindle, A detection means for detecting that the cutting tool on the cutting tool stand has come into contact with the workpiece at the predetermined contact position, A control device for controlling the spindle and the tool holder, A machine tool equipped with, The control device is With the chuck closed, the spindle is advanced a first predetermined distance in the axial direction of the workpiece, and then the tool holder is moved until the cutting tool reaches the predetermined contact position. After the execution of the first control, the tool holder is moved in a direction that moves the cutting tool away from the predetermined contact position, the spindle is retracted by a second predetermined distance in the axial direction of the workpiece with the chuck closed, and then the tool holder is moved again until the cutting tool reaches the predetermined contact position. If, in the first control, contact between the cutting tool and the workpiece is not detected by the detection means, or if, in the first control, contact between the cutting tool and the workpiece is detected by the detection means, and in the second control, contact between the cutting tool and the workpiece is detected by the detection means, it is determined that the state of the workpiece is such that machining by the machine tool cannot be started. Machine tools.

2. The control device is In the first control, if contact between the cutting tool and the workpiece is detected by the detection means, and in the second control, if contact between the cutting tool and the workpiece is not detected by the detection means, it is determined that the state of the workpiece is such that machining by the machine tool can begin. The machine tool according to claim 1.

3. The system further comprises a notification means for notifying that the state of the workpiece is such that it is impossible to start machining by the machine tool. The machine tool according to claim 1 or 2.

4. The machine tool according to claim 1 or 2, wherein the detection means includes a touch sensor provided on the tool holder.

5. The machine tool according to claim 1 or 2, wherein the detection means includes a torque detection device for detecting the torque of a motor that moves the tool holder.

6. A spindle that holds a rod-shaped workpiece with the end facing the workpiece protruding using a chuck, A tool holder is provided with a cutting tool for machining the portion of the workpiece that protrudes from the spindle, A guide bush that supports the workpiece between the cutting tool on the cutting tool holder and the chuck of the spindle, where the cutting tool and the workpiece come into contact when the workpiece is machined by the cutting tool on the cutting tool holder and the chuck of the spindle, A detection means for detecting that the cutting tool on the cutting tool stand has come into contact with the workpiece at the predetermined contact position, A control method for a machine tool, comprising: The first step involves moving the spindle forward a first predetermined distance in the axial direction of the workpiece with the chuck closed, and then moving the tool holder until the cutting tool reaches the predetermined contact position. After the execution of the first step, the tool holder is moved in a direction that moves the cutting tool away from the predetermined contact position, the spindle is moved back a second predetermined distance in the axial direction of the workpiece with the chuck closed, and then the tool holder is moved again until the cutting tool reaches the predetermined contact position, in which case the second step is performed. If contact between the cutting tool and the workpiece is not detected by the detection means in the first step, or if contact between the cutting tool and the workpiece is detected by the detection means in the first step and contact between the cutting tool and the workpiece is detected by the detection means in the second step, it is determined that the state of the workpiece is such that machining by the machine tool cannot be started. including, A method for controlling machine tools.

7. The process further includes determining that the state of the workpiece is such that machining by the machine tool can begin if, in the first step, contact between the cutting tool and the workpiece is detected by the detection means, and in the second step, contact between the cutting tool and the workpiece is not detected by the detection means. The control method for a machine tool according to claim 6.

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