Cutting equipment

Abstract

To provide a cutting device capable of improving working accuracy of a workpiece by detecting breakage of a tool quickly.SOLUTION: A cutting device 1 includes a head 5 having a spindle driving part 51 which rotationally drives a rotary spindle provided with a tool 20 fixed to the tip part, a proximity sensor 34, a signal acquisition part which acquires a signal wave form of a detection signal outputted from the proximity sensor 34 when rotating the rotary spindle 52 while moving the head 5 so that the proximity sensor 34 opposes to the lateral side of the tool 20 before and after cutting work of a workpiece W using the tool 20, and a determination part which determines the presence or absence of breakage of the tool 20 based on the presence or absence of a difference of the signal waveform acquired before and after cutting work.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a cutting device. [Background technology]

[0002] A gun drill has been proposed in which a cutting blade, a steel pipe, and a handle are joined together with a silver brazing joint, one end of which is connected to a copper plate provided at the end of the handle, the other end of which is connected with a conductive adhesive near the base end of the cutting blade, and an enamel wire is embedded in the surfaces of the cutting blade, the steel pipe, and the handle while being electrically insulated from these (see, for example, Patent Document 1).When this gun drill breaks at the silver brazing joint during use, the enamel wire is simultaneously cut and the conductivity of the enamel wire is interrupted, so that breakage of the gun drill can be detected by monitoring the conductivity of the enamel wire. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-225719 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of the gun drill described in Patent Document 1, for example, if the tip of the cutting blade where the enamel wire is not embedded breaks, the breakage of the cutting blade cannot be detected. Therefore, even if the tip of the cutting blade is broken, machining of the workpiece may continue, which may result in a significant decrease in the machining accuracy of the workpiece.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a cutting device that can improve the machining accuracy of a workpiece by quickly detecting tool breakage. [Means for solving the problem]

[0006] In order to achieve the above object, a cutting apparatus according to the present invention comprises: a head having a spindle drive unit that rotates a rotating spindle having a tool fixed to a tip end thereof; A first proximity sensor; a signal acquiring unit that acquires detection signal information indicating a magnitude of a detection signal output from the first proximity sensor when the rotating spindle is rotated in a state in which the head is moved so that the first proximity sensor faces a side of the tool before and after cutting a workpiece using the tool; and a determination unit that determines whether or not the tool is broken based on the presence or absence of a difference in signal waveforms corresponding to a time transition of the magnitude of the detection signal indicated by each of the detection signal information acquired before and after the cutting process; and A holding unit including a workpiece holding portion that holds the workpiece and a rotation drive portion that rotates the workpiece holding portion; A second proximity sensor disposed on the head; Equipped with picture, the signal acquisition unit acquires a signal waveform of a detection signal output from the second proximity sensor when the workpiece holding unit is rotated in a state in which the head is moved so that the second proximity sensor faces a side of the workpiece after cutting processing of the workpiece using the tool, The determination unit determines whether or not there is a broken piece of the tool attached to the workpiece based on a signal waveform acquired from the second proximity sensor after the cutting process. . Effect of the Invention

[0007] According to the present invention, the signal acquisition unit acquires detection signal information indicating the magnitude of the detection signal output from the proximity sensor when the rotating spindle is rotated while the head is moved so that the proximity sensor is disposed to the side of the tool before and after cutting the workpiece. The determination unit then determines whether or not the tool is broken based on the presence or absence of a difference in signal waveforms corresponding to the time transition of the magnitude of the detection signal indicated by each of the detection signal information acquired before and after the cutting process. This makes it possible to quickly detect breakage of the tip of the tool during cutting, thereby improving the machining accuracy of the workpiece. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a cutting device according to an embodiment of the present invention; [Diagram 2] 1 is a partially cutaway side view of a cutting device according to an embodiment. [Diagram 3] 1A is a perspective view of a head according to an embodiment, and FIG. 1B is a view of the head according to the embodiment as viewed from the +Z direction side. [Figure 4] FIG. 2 is a side view of the holding unit according to the embodiment. [Diagram 5] FIG. 2 is a block diagram showing a configuration of a control unit according to the embodiment. [Figure 6] FIG. 1A is a diagram showing a state in which a head according to an embodiment is positioned to the side of a proximity sensor provided in a holding unit, and FIG. 1B is a diagram showing a state in which a head according to an embodiment is positioned to the side of a workpiece. [Figure 7] 5 is a flowchart showing an example of the flow of a cutting process executed by the cutting device according to the embodiment. [Figure 8] 5A and 5B show signal waveforms acquired by a signal acquisition unit in the embodiment, in which (A) is a diagram showing an example of a signal waveform before cutting processing, and (B) is a diagram showing an example of a signal waveform after cutting processing when a part of a tool is broken. [Figure 9] 5 is a flowchart showing an example of the flow of a cutting process executed by the cutting device according to the embodiment. [Figure 10] FIG. 11 is a cross-sectional view showing a part of a holding unit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a cutting device according to an embodiment of the present invention will be described with reference to the drawings. The cutting device according to this embodiment includes a head having a spindle drive unit that rotates a rotating spindle with a tool fixed to its tip, a proximity sensor, a signal acquisition unit that acquires detection signal information indicating the magnitude of a detection signal output from the proximity sensor when the rotating spindle is rotated in a state in which the head is moved so that the proximity sensor faces the side of the tool before and after cutting a workpiece using the tool, and a determination unit that determines whether the tool is broken or not based on the presence or absence of a difference in signal waveforms corresponding to the time transition of the magnitude of the detection signal indicated by each of the detection signal information acquired before and after cutting. The cutting device according to this embodiment is particularly used in the medical field where it is necessary to machine a workpiece with high precision while maintaining the processing area where the workpiece is processed in a clean environment. This cutting device is used, for example, to prepare so-called bone screws for joining a fractured part of a patient from a bone fragment taken from the patient, or a filling member having a shape that matches the shape of a missing part of the patient's bone to fill the missing part of the patient's bone. It should be noted that the cutting processing device according to this embodiment is not limited to processing the bone fragments described above, but may also be applied to processing other biological tissues or materials different from biological tissues.

[0010] As shown in FIG. 1, the cutting apparatus 1 according to the present embodiment includes a holding unit 3 for holding a workpiece W, a head 5 arranged opposite the holding unit 3 for holding a tool 20, a control unit (not shown) for controlling the operation of the holding unit 3 and the head 5, and a display panel 11. The cutting apparatus 1 is rectangular box-shaped, and has an opening 10b for inserting and removing the workpiece W on the side wall on the +Y direction side, and includes a housing 10 for accommodating the holding unit 3, the head 5, and the control unit on the inside. Although not shown in FIG. 1, the opening 10b can be closed by a door 15 described later. As shown in FIG. 2, the cutting apparatus 1 includes an interior case 13 that is rectangular box-shaped with one side open, and has parts of the holding unit 3 and the head 5 arranged on the inside, a first cover 141 and a second cover 142 made of a soft material, and a door 15 that covers the opening 10b from the +Y direction side. The cutting device 1 also includes an elevation drive unit 44 that raises and lowers the head 5 in the vertical direction, an X-direction drive unit 71 that drives the head 5 along the X-axis direction, and a Y-direction drive unit 76 that drives the head 5 along the Y-axis direction. An interior case 13 is disposed inside the housing 10, and a display panel 11 is attached to the +Z direction side of an opening 10b in the side wall on the +Y direction side. The display panel 11 displays, for example, the progress of cutting processing performed on the workpiece W.

[0011] The interior case 13 has a machining area S1 formed therein where the workpiece W is machined. The machining area S1 is surrounded by the interior case 13 and the door 15. The interior case 13 is disposed in the housing 10 with the open portion facing the opening 10b of the housing 10, and openings 13a and 13b are provided on the peripheral wall on the +Z direction side and the peripheral wall on the -Y direction side, respectively. Here, the opening 13a is a first opening through which the head 5 is inserted, and the opening 13b is a second opening through which the holding unit 3 is inserted. In addition, a support member 12 that supports the head 5, the holding unit 3, etc. is disposed in the outer area S2 of the interior case 13 inside the housing 10.

[0012] The head 5 includes a rotating spindle 52 having a chuck 53 at one end in the longitudinal direction for holding the tool 20, a spindle drive unit 51 for rotating the rotating spindle 52 around a central axis along the longitudinal direction, a head cover 54, and a proximity sensor 55. The chuck 53 includes a chuck (not shown) and an actuator (not shown) for driving the chuck, and the chuck opens and closes based on a control signal input from the control unit. The head 5 is fixed to a slider 422 slidably held on a rail 421 extending along the Z-axis direction on the +Y-direction side of the base 41. The lift drive unit 44 includes a long feed screw (not shown) that is screwed into a nut portion (not shown) provided on a part of the slider 422 arranged along the Z-axis direction, and a motor (not shown) that is connected to the feed screw and rotates the feed screw. The lifting drive unit 44 lifts and lowers the slider 422 and the head 5 fixed to the slider 422 along the Z-axis direction by rotating a feed screw arranged along the Z-axis direction.

[0013] The base 41 is fixed via a bracket 43 to a slider 722 slidably held on a rail 721 extending along the X-axis direction. The X-direction driving unit 71 has a long feed screw (not shown) that is arranged along the X-axis direction and is screwed into a nut portion (not shown) provided on a part of the bracket 43, and a motor (not shown) that is connected to the feed screw and rotates the feed screw. The X-direction driving unit 71 moves the slider 722 and the base 41 fixed to the slider 722 along the X-axis direction by rotating the feed screw arranged along the X-axis direction. As a result, the X-direction driving unit 71 moves the base 41 and the head 5 together along the X-axis direction via the feed screw. The rail 721 is supported by a slider 772 whose both ends in the longitudinal direction are slidably held on two rails 771 extending along the Y-axis direction. The Y-direction driving unit 76 has a long feed screw (not shown) that is arranged along the Y-axis direction and screws into a nut portion (not shown) provided on a part of the base 41, and a motor (not shown) that is connected to the feed screw and rotates the feed screw. The Y-direction driving unit 76 moves the slider 772 and the rail 721 supported by the slider 772 along the Y-axis direction by rotating the feed screw arranged along the Y-axis direction. In this way, the Y-direction driving unit 76 moves the rail 721, the slider 722, the base 41, and the head 5 together along the Y-axis direction via the feed screw.

[0014] As shown in FIG. 3(A), the head cover 54 is a square cylinder with a bottom, and has an opening 54a at the bottom wall through which the tool 20 is inserted, and the spindle drive unit 51 and the tip of the rotating spindle 52 are disposed inside. The proximity sensor 55 is, for example, an induction type proximity sensor, and is a second proximity sensor having a sensor unit 551 and a signal output unit 552 as shown in FIG. 3(B). The sensor unit 551 has an induction coil (not shown) and a flat rectangular plate-shaped package in which the induction coil is embedded inside. The signal output unit 552 has a flat rectangular plate-shaped package, and has an oscillation circuit (not shown) connected to the induction coil inside, an amplitude detection circuit (not shown) that detects the amplitude of the output current of the oscillation circuit and outputs a detection voltage reflecting the magnitude of the detected amplitude, and an output circuit (not shown) that generates a detection signal based on the detection voltage output from the amplitude detection circuit and transmits it to the control unit. The sensor unit 551 and the signal output unit 552 are disposed in a region between the main shaft drive unit 51 and the inside of the head cover 54 .

[0015] 4, the holding unit 3 has a workpiece holding section 32 for holding a workpiece W, a tool holding section 33 that is substantially circular with a bottom and holds the tool 20 with the tool 20 inserted inside, a box-shaped unit body 31, and a proximity sensor 34. As shown in FIG. 2, the holding unit 3 has a rotation drive section 81 that rotates the entire unit body 31 about a rotation axis (hereinafter referred to as "axis B") JB extending in the longitudinal direction of the unit body 31, and a rotation drive section 86 that rotates the workpiece holding section 32 about a rotation axis (hereinafter referred to as "axis C") JC extending in a direction perpendicular to the longitudinal direction of the unit body 31.

[0016] The rotation drive unit 86 is disposed inside the unit body 31, and has a motor that rotates a shaft (not shown) that extends along the C-axis JC and has a tip connected to the workpiece holding unit 32. The rotation drive unit 81 supports the -Y direction end of a cylindrical shaft 82 that extends along the B-axis, and has a motor that rotates the shaft 82 around the B-axis JB. The unit body 31 is fixed to the +Y direction end of the shaft 82. The rotation drive unit 81 is supported by a support member 12 provided outside the interior case 13 inside the housing 10.

[0017] The unit body 31 has a first portion 311 in the shape of a hollow rectangular parallelepiped, and a second portion 312 in the shape of a rectangular box, which is continuous with the first portion 311 at the end portion on the +Y direction side of the first portion 311. As shown in FIG. 2, the end portion on the -Y direction side of the first portion 311 is fixed to the shaft 82. When the shaft 82 of the rotation drive unit 81 rotates around the B axis JB, the unit body 31 rotates around the B axis JB accordingly. The workpiece holding portion 32 is a chuck that clamps the base end portion of the long workpiece W. The workpiece holding portion 32 is fixed to the peripheral wall of the second portion 312 of the unit body 31. The tool holding portion 33 is fixed to the unit body 31 such that the inside of the tool holding portion 33 communicates with the outside of the unit body 31 and the outer wall of the tool holding portion 33 is isolated from the outside of the unit body 31 when the tool 20 is not inserted in the tool holding portion 33.

[0018] The proximity sensor 34 is, for example, an induction type proximity sensor, and is a first proximity sensor having a sensor unit 341 and a signal output unit 342. The sensor unit 341 has an induction coil (not shown) and a flat rectangular plate-shaped package with the induction coil embedded inside. The signal output unit 342 has a flat rectangular plate-shaped package and has an oscillation circuit (not shown) connected to the induction coil inside, an amplitude detection circuit (not shown) that detects the amplitude of the output current of the oscillation circuit and outputs a detection voltage reflecting the magnitude of the detected amplitude, and an output circuit (not shown) that generates a detection signal based on the detection voltage output from the amplitude detection circuit and transmits it to the control unit. The sensor unit 341 is arranged inside the side wall facing the workpiece holding unit 32 in the Y-axis direction in the first part 311 of the unit main body 31, and the signal output unit 342 is arranged at a position adjacent to the workpiece holding unit 32 inside the second part 312 of the unit main body 31.

[0019] The first cover 141 is preferably made of a soft material such as a rubber thin film or a vinyl film, and can be sterilized, for example, using ethylene oxide gas. The first cover 141 is cylindrical and has a shape that tapers from one end to the other end in the cylindrical axis direction, the entire one end in the cylindrical axis direction is fixed to the outer periphery of the opening 13a of the interior case 13, and the entire other end in the cylindrical axis direction is fixed to the entire end opposite to the bottom wall side of the head cover 54. The second cover 142 is also preferably made of a soft material such as a rubber thin film or a vinyl film, and can be sterilized, for example, using ethylene oxide gas. The second cover 142 is ... cylindrical and has a shape that tapers from one end to the other end in the cylindrical axis direction, the entire one end in the cylindrical axis direction is fixed to the outer periphery of the opening 13b of the interior case 13, and the entire other end in the cylindrical axis direction is fixed to the unit body 31 of the holding unit 3.

[0020] The control unit includes, for example, a PLC (Programmable Logic Controller) including a CPU (Central Processing Unit) unit and an input / output control unit, and an input device such as a keyboard or a touch panel connected to the PLC. As shown in FIG. 5, the control unit 100 includes a CPU unit 101, a main memory unit 102, an auxiliary memory unit 103, an input unit 105, interfaces 106 and 104, and a bus 109 connecting each unit. The control unit 100 also includes drive circuits 107a, 107b, 107c, 107d, 107e, 107f, and 107g. The main memory unit 102 is a volatile memory such as a RAM (Random Access Memory), and is used as a work area for the CPU unit 101. The auxiliary memory unit 103 is a non-volatile memory such as a semiconductor memory, and stores programs for realizing various functions of the control unit 100, including a machining program. The input unit 105 includes the above-mentioned input device and an interface for connecting the input device to the bus 109. When the input unit 105 receives various pieces of operation information input by the user operating the input device, it outputs the received various pieces of operation information to the CPU unit 101. The interface 106 is connected to the drive circuits 107a, 107b, 107c, 107d, 107e, 107f, and 107g, and converts control information input from the CPU unit 101 into a control signal and outputs it to the drive circuits 107a, 107b, 107c, 107d, 107e, 107f, and 107g. The interface 106 is also connected to the proximity sensors 34 and 55, and converts detection signals input from the proximity sensors 34 and 55 into detection signal information and outputs it to the CPU unit 101. The interface 104 outputs notification information input from the CPU unit 101 to the display panel 11 to notify the user of the presence or absence of breakage of the tool 20.

[0021] The drive circuit 107a drives the spindle drive unit 51 based on a control signal input via the interface 106. The drive circuit 107b drives the lift drive unit 44 based on a control signal input via the interface 106. The drive circuit 107c drives the X-direction drive unit 71 based on a control signal input via the interface 106, and the drive circuit 107d drives the Y-direction drive unit 76 based on a control signal input via the interface 106. The drive circuit 107e drives the rotation drive unit 81 based on a control signal input via the interface 106, and the drive circuit 107f drives the rotation drive unit 86 based on a control signal input via the interface 106. The drive circuit 107g drives the chuck 53 based on a control signal input via the interface 106.

[0022] The CPU unit 101 functions as a head control unit 111, a holding unit control unit 112, a signal acquisition unit 113, a determination unit 114, and a notification unit 115 by reading out the above-mentioned programs stored in the auxiliary storage unit 103 into the main storage unit 102 and executing them. The auxiliary storage unit 103 also has a reference signal waveform storage unit 131 that stores signal waveform information obtained by the proximity sensor 34, which reflects the shape of the tool 20 that serves as a reference for determining whether the tool 20 is broken before cutting the workpiece W. The main storage unit 102 temporarily stores signal waveform information indicating the waveform of the detection signal of the proximity sensor 34 for the tool 20 after cutting the workpiece W, and signal waveform information indicating the waveform of the detection signal of the proximity sensor 55 for the workpiece W. The reference signal waveform memory unit 131 stores signal waveform information indicating the signal waveform of the detection signal output from the proximity sensor 34 when the rotating spindle 52 is rotated while the head 5 is moved so that the proximity sensor 34 provided on the holding unit 3 faces the side of the tool 20 before cutting the workpiece W, in correspondence with tool identification information that identifies the tool 20.

[0023] The signal waveform storage unit 121 temporarily stores signal waveform information indicating a waveform of a detection signal output from the proximity sensor 34 when the rotating spindle 52 is rotated in a state in which the head 5 is moved so that the proximity sensor 34 provided on the holding unit 3 faces the side of the tool 20 after cutting the workpiece W. The signal waveform storage unit 121 further temporarily stores signal waveform information indicating a waveform of a detection signal output from the proximity sensor 55 when the workpiece holding unit 32 is rotated in a state in which the head 5 is moved so that the proximity sensor 55 provided on the head 5 faces the side of the workpiece W after cutting the workpiece W.

[0024] The head control unit 111 generates control information to rotate the rotating spindle 52 or to keep the rotating spindle 52 in a non-rotating state according to the cutting method of the workpiece W, and outputs the control information to the interface 106. At this time, the drive circuit 107a operates or stops the spindle drive unit 51 based on the control signal input from the interface 106. The head control unit 111 also generates control information for raising and lowering the head 5 according to a machining program corresponding to the shape of the workpiece W, and outputs the control information to the interface 106. At this time, the drive circuit 107b operates the lift drive unit 44 based on the control signal input from the interface 106. The head control unit 111 also generates control information for holding or releasing the tool 20 in the chuck 53, and outputs the control information to the interface 106. At this time, the drive circuit 107g causes the chuck 53 to hold the tool 20 or release the tool 20 from the holding state based on the control signal input from the interface 106. Furthermore, the head control unit 111 generates control information for moving the head 5 in the X-axis direction and the Y-axis direction, and outputs the control information to the interface 106. At this time, the drive circuits 107c and 107d operate and stop the X-direction drive unit 71 and the Y-direction drive unit 76, respectively, based on the control signal input from the interface 106.

[0025] Moreover, the head control unit 111 generates control information for moving the head 5 so that the sensor unit 341 of the proximity sensor 34 provided in the holding unit 3 faces the side of the tool 20 before and after cutting the workpiece W, as shown in Fig. 6(A), and outputs the control information to the interface 106. Furthermore, after cutting the workpiece W, the head control unit 111 generates control information for moving the head 5 so that the proximity sensor 55 provided in the head 5 faces the side of the workpiece W, as shown in Fig. 6(B), and outputs the control information to the interface 106.

[0026] Returning to Fig. 5, the holding unit control section 112 generates control information for rotating the entire unit body 31 around the B-axis JB and outputs it to the interface 106. At this time, the drive circuit 107e operates or stops the rotation drive section 81 based on the control signal input from the interface 106. The holding unit control section 112 also generates control information for rotating the workpiece holding section 32 around the C-axis JC and outputs it to the interface 106. At this time, the drive circuit 107f operates or stops the rotation drive section 86 based on the control signal input from the interface 106.

[0027] The signal acquiring unit 113 acquires detection signal information indicating the magnitude of the detection signal output from the proximity sensors 34, 55. Here, before cutting the workpiece W, the signal acquiring unit 113 acquires detection signal information indicating the magnitude of the detection signal output from the proximity sensor 34 when the rotating spindle 52 of the head 5 is rotated in a state in which the head 5 is moved so that the sensor portion 341 of the proximity sensor 34 faces the side of the tool 20 as shown in FIG. 6(A). Then, before cutting the workpiece W, the signal acquiring unit 113 converts the detection signal information of the proximity sensor 34 acquired for each of the multiple tools 20 used in the cutting process into detection signal information indicating the magnitude of the detection signal output from the proximity sensor 34 when the rotating spindle 52 of the head 5 is rotated. 34The signal acquisition unit 113 associates the sampling time information indicating the sampling time by the tool identification information of each of the multiple tools 20 with the tool identification information of each of the multiple tools 20, and stores the result as reference signal waveform information in the reference signal waveform storage unit 131. Furthermore, after the cutting of the workpiece W, the signal acquisition unit 113 acquires detection signal information indicating the magnitude of the detection signal output from the proximity sensor 34 when the head holding the tool 20 used in the cutting is moved so that the proximity sensor 34 faces the side of the tool 20 and the rotating main shaft 52 of the head 5 is rotated. Then, the signal acquisition unit 113 stores the detection signal information of the proximity sensor 34 acquired after the cutting of the workpiece W as the magnitude of the detection signal output from the proximity sensor 34 when the head holding the tool 20 used in the cutting is moved so that the proximity sensor 34 faces the side of the tool 20. 34 The signal waveform is stored in the signal waveform storage unit 121 in association with sampling time information indicating the sampling time according to the sampling time.

[0028] Furthermore, after cutting the workpiece W using the tool 20, the signal acquiring unit 113 acquires detection signal information indicating the magnitude of the detection signal output from the proximity sensor 55 when the workpiece holding unit 32 is rotated in a state in which the head 5 is moved so that the sensor portion 551 of the proximity sensor 55 faces the side of the workpiece W as shown in Fig. 6(B). Then, the signal acquiring unit 113 stores the detection signal information of the proximity sensor 55 acquired after cutting the workpiece W in the signal waveform storage unit 121 in association with sampling time information indicating the sampling time by the proximity sensor 55.

[0029] The determination unit 114 determines whether the tool 20 is broken or not based on the magnitude of the detection signal indicated by each of the detection signal information acquired before and after cutting the workpiece W by the proximity sensor 34, that is, the presence or absence of a difference in the signal waveform corresponding to the time transition of the amplitude value of the detection signal. Specifically, for example, the determination unit 114 first performs a process of synchronizing the sampling time corresponding to the detection signal information constituting the reference signal waveform information stored in the reference signal waveform storage unit 131 with the sampling time corresponding to the detection signal information acquired by the proximity sensor 34 stored in the signal waveform storage unit 121. Next, the determination unit 114 calculates the difference value between the amplitude value indicated by the detection signal information constituting the reference signal waveform information and the amplitude value indicated by the detection signal information stored in the signal waveform storage unit 121 at the same sampling time for all sampling times that are synchronized with each other, and calculates the sum of the calculated difference values ​​as a difference accumulation value. Then, the determination unit 114 determines that the tool 20 is broken if the calculated difference accumulation value is equal to or greater than a preset difference accumulation threshold value. Furthermore, the determination unit 114 determines the presence or absence of broken pieces of the tool 20 adhering to the workpiece W, based on the signal waveform information acquired by the proximity sensor 55 after cutting the workpiece W. Specifically, the determination unit 114 determines that broken pieces of the tool 20 are adhering to the workpiece W, for example, when a peak waveform exists in the signal waveform corresponding to the time transition of the amplitude value of the detection signal indicated by each piece of detection signal information acquired by the proximity sensor 55 and stored in the signal waveform storage unit 121, and the difference value between the peak value of the peak waveform and the average value of the signal waveform is equal to or greater than a preset difference threshold value.

[0030] Based on the judgment result by the judgment unit 114, the notification unit 115 generates notification information to notify the worker of whether the tool 20 is broken and whether there are any broken pieces of the tool 20 attached to the workpiece W, and outputs the notification information to the interface 104.

[0031] Next, the cutting process performed by the cutting device 1 according to the present embodiment will be described with reference to FIGS. 7 to 9. Here, the cutting device 1 will be described as performing at least one processing step on the workpiece W in the cutting process. In addition, the holding unit 3 is assumed to be maintained in an orientation in which the tool holding part 33 faces the +Z direction side in the initial state. Furthermore, the head 5 is assumed to be disposed in an initial position on the +Z direction side of the holding unit 3 in the initial state. First, as shown in FIG. 7, when the cutting process is started, the cutting device 1 identifies one tool 20 from at least one tool 20 used in the cutting process (step S1). Next, the cutting device 1 moves the head 5 to a position to receive the identified tool 20, and then causes the head 5 to hold the identified tool 20 (step S2). Specifically, the head control unit 111 identifies one tool 20 from at least one tool 20 used in the cutting process, and controls the operation of the X-direction drive unit 71 and the Y-direction drive unit 76 so that the head 5 moves from the initial position to the +Z direction side of the identified tool 20. The holding unit control unit 112 also controls the operation of the rotation drive unit 81 to rotate the holding unit 3 around the B axis JB so that the workpiece W held by the holding unit 3 is oriented so as to face vertically upward. The head control unit 111 then controls the operation of the lift drive unit 44 to lower the head 5 in the -Z direction to a position for receiving the identified tool 20. Furthermore, the head control unit 111 controls the operation of the chuck 53 so that the identified tool 20 is held by the chuck 53 with the head 5 disposed at the position for receiving the identified tool.

[0032] Next, the cutting apparatus 1 moves the head 5 to a position where the tool 20 held therein faces the proximity sensor 34 of the holding unit 3 (step S3). Specifically, the head control unit 111 controls the operations of the X-direction drive unit 71, the Y-direction drive unit 76, and the elevation drive unit 44 so that the head 5 is disposed at a position where the sensor unit 341 of the proximity sensor 34 provided in the holding unit 3 faces the side of the tool 20, as shown in FIG. 6(A). Returning to FIG. 7, the cutting apparatus 1 then acquires signal waveform information obtained by the proximity sensor 34 while rotating the tool 20 and stores the signal waveform information in the reference signal waveform storage unit 131 (step S4). Specifically, the head control unit 111 controls the operation of the spindle drive unit 51 so that the rotating spindle 52 holding the tool 20 rotates at a preset rotation speed, while the signal acquisition unit 113 acquires detection signal information indicating the magnitude of the detection signal output from the proximity sensor 34. Then, the signal acquisition unit 113 stores the acquired detection signal information in the reference signal waveform storage unit 131 in association with the sampling time information and the tool identification information of the identified tool 20. The head control unit 111 rotates the rotating spindle 52 by a preset number of rotations and then stops the rotation of the rotating spindle 52. Next, the cutting device 1 moves the head 5 to a position where the tool 20 held by the head 5 is transferred to the holding unit 3, and then stores the tool 20 held by the head 5 in the tool holding portion 33 of the holding unit 3 (step S5). Specifically, the head control unit 111 controls the operations of the X-direction drive unit 71, the Y-direction drive unit 76, and the lift drive unit 44 so that the head 5 is positioned at a position where a part of the tool 20 held by the head 5 is positioned inside the tool holding portion 33 of the holding unit 3. The holding unit control unit 112 also controls the operation of the rotation drive unit 81 so that the holding unit 3 is rotated around the B axis JB to make the workpiece W held by the holding unit 3 face vertically upward. Then, the head control unit 111 controls the operation of the chuck 53 so as to release the tool 20 from the chuck 53 .

[0033] Next, the cutting device 1 judges whether or not the acquisition of signal waveform information for all the tools 20 used in the cutting process has been completed (step S6). Here, it is assumed that the cutting device 1 judges that there is a tool 20 for which signal waveform information has not yet been acquired among all the tools 20 used in the cutting process (step S6: No). In this case, the cutting device 1 identifies one of the tools 20 for which signal waveform information has not yet been acquired (step S1), and executes a series of processes from step S2 onwards again. On the other hand, it is assumed that the cutting device 1 judges that the acquisition of signal waveform information for all the tools 20 used in the cutting process has been completed (step S6: Yes). In this case, the cutting device 1 identifies the tool 20 to be used in the first processing step according to the processing program, and holds the identified tool 20 (step S7). Thereafter, the cutting device 1 moves the head 5 to a position to receive the identified tool 20, and then holds the identified tool 20 in the head 5 (step S8). Next, the cutting device 1 starts one processing step included in the cutting process (step S9). Specifically, the head control unit 111 controls the operation of the spindle drive unit 51, the X-direction drive unit 71, the Y-direction drive unit 76, and the lift drive unit 44 so that the head 5 is moved while rotating the rotating spindle 52 holding the tool 20 in accordance with the contents of the processing step, and the tip of the tool 20 is brought into contact with the workpiece W. Here, the holding unit control unit 112 controls the operation of the rotation drive unit 81 so that the workpiece holding unit 32 is maintained in an attitude facing the +Z direction or a direction tilted from the Z axis in accordance with the contents of the processing step. Alternatively, the head control unit 111 controls the operation of the spindle drive unit 51, the X-direction drive unit 71, the Y-direction drive unit 76, and the lift drive unit 44 so that the head 5 is moved while maintaining the rotating spindle 52 holding the tool 20 in a stopped state in accordance with the contents of the processing step, and the tip of the tool 20 is brought into contact with the workpiece W. Here, the holding unit control unit 112 controls the operation of the rotation drive units 81, 86 so as to rotate the workpiece holding unit 32 and maintain the workpiece holding unit 32 in an orientation facing in the +Z direction or in a direction tilted from the Z axis, depending on the content of the processing step.

[0034] Next, when one machining step is completed (step S10), the cutting device 1 moves the head 5 to a position where the tool 20 held by the head 5 faces the proximity sensor 34 of the holding unit 3 as shown in Fig. 6(A) (step S11). Returning to Fig. 7, the cutting device 1 then acquires signal waveform information obtained by the proximity sensor 34 while rotating the tool 20 and stores it in the signal waveform storage unit 121 (step S12).

[0035] Next, the cutting processing device 1 judges whether or not there is a difference in the signal waveform indicated by the signal waveform information acquired by the proximity sensor 34 before and after the processing step (step S13). Specifically, the judgment unit 114 compares the signal waveform corresponding to the time transition of the amplitude value of the detection signal indicated by each of the detection signal information acquired by the proximity sensor 34 stored in the signal waveform storage unit 121 with the signal waveform corresponding to the time transition of the amplitude value of the detection signal indicated by each of the detection signal information stored in the reference signal waveform storage unit 131, and judges whether or not there is a difference in the signal waveform. Here, the judgment unit 114 judges that there is a difference in the signal waveform when, for example, the signal waveform corresponding to the reference signal waveform information is a waveform shown in FIG. 8(A), and the signal waveform corresponding to the detection signal information stored in the signal waveform storage unit 121 is different from the signal waveform shown in FIG. 8(A), for example, as shown in FIG. 8(B). Returning to FIG. 7, when the cutting processing device 1 judges that there is a difference in the signal waveform (step S13: Yes), the processing of step S15 described later is executed. On the other hand, when the cutting device 1 determines that the signal waveforms are the same (step S13: No), it determines whether or not all the processing steps included in the cutting process have been completed (step S14). Here, it is assumed that the cutting device 1 determines that there is a processing step that has not yet been completed among the processing steps included in the cutting process (step S14: No). In this case, the cutting device 1 identifies the tool 20 to be used in the next processing step (step S7) and executes the series of processing from step S8 onwards again.

[0036] On the other hand, when the cutting device 1 determines that all the processing steps included in the cutting process have been completed (step S14: Yes), it moves the head 5 to a position where the proximity sensor 55 of the head 5 faces the workpiece W (step S15), as shown in Fig. 9. Specifically, the head control unit 111 controls the operations of the X-direction drive unit 71, the Y-direction drive unit 76, and the lift drive unit 44 so that the head 5 is disposed at a position where the sensor unit 551 of the proximity sensor 55 provided on the head 5 faces the side of the workpiece W held by the workpiece holding unit 32, as shown in Fig. 6(B). Returning to Fig. 9, the cutting device 1 then acquires signal waveform information obtained by the proximity sensor 55 while rotating the workpiece W and stores it in the signal waveform storage unit 121 (step S16). Specifically, the holding unit control unit 112 controls the operation of the rotation drive unit 86 so that the workpiece holding unit 32 holding the workpiece W rotates, while the signal acquisition unit 113 acquires detection signal information indicating the magnitude of the detection signal output from the proximity sensor 55, and stores the acquired detection signal information in the signal waveform storage unit 121 in association with the sampling time information. Thereafter, the cutting device 1 determines the presence or absence of a broken piece of the tool 20 attached to the workpiece W based on the signal waveform corresponding to the time transition of the amplitude value of the detection signal indicated by each of the detection signal information acquired by the proximity sensor 55 stored in the signal waveform storage unit 121 (step S17). Next, the cutting device 1 generates notification information for notifying the operator of the presence or absence of the breakage of the tool 20 and the presence or absence of the broken piece of the tool 20 attached to the workpiece W, and displays it on the display panel 11 (step S18). Specifically, the notification unit 115 generates notification information indicating the judgment result by the judgment unit 114, and outputs it to the interface 104. Thereafter, the cutting processing ends.

[0037] As described above, according to the cutting device 1 of this embodiment, the signal acquisition unit 113 acquires detection signal information indicating the magnitude of the detection signal output from the proximity sensor 34 when the rotating spindle 52 is rotated in a state in which the head 5 is moved so that the proximity sensor 34 is disposed to the side of the tool 20 before and after cutting the workpiece W. Then, the determination unit 114 determines whether or not the tool 20 is broken based on the presence or absence of a difference in signal waveforms corresponding to the time transition of the magnitude of the detection signal indicated by each of the detection signal information acquired before and after the cutting process. This makes it possible to quickly detect breakage of the tip of the tool 20 during cutting the workpiece W, thereby improving the machining accuracy of the workpiece W.

[0038] However, when the dimensions of the workpiece W become smaller, the dimensions of the tool 20 used to process the workpiece W also become smaller accordingly. When fine cutting is performed on the workpiece W, even a small breakage of the tool 20 significantly affects the processing accuracy. However, there are cases where the worker cannot visually check the small breakage of the tool 20. In contrast, the cutting device 1 according to the present embodiment utilizes the correlation between the waveform of the detection signal output from the proximity sensor 34 and the shape of the tool 20, and acquires detection signal information indicating the amplitude of the detection signal of the proximity sensor 34 while rotating the rotating spindle 52 holding the tool 20 before and after cutting the workpiece W, and detects whether or not the tool 20 is broken during cutting by comparing the signal waveforms corresponding to the time transition of the amplitude of the detection signal indicated by each of the acquired detection signal information. Therefore, it is possible to detect a small breakage of the tool 20 that is difficult for the worker to visually check.

[0039] Further, the proximity sensor 34 according to this embodiment is disposed inside the unit body 31 of the holding unit 3, and the proximity sensor 55 is disposed inside the head cover 54. As a result, the proximity sensors 34, 55 are disposed in a state isolated from the machining area S1, so that the cleanliness of the machining area S1 can be maintained. In addition, there is no need to wash or sterilize the proximity sensors 34, 55 every time cutting is performed on the workpiece W, which is an advantage in that the workload of the worker performing cutting of the workpiece W is reduced.

[0040] Furthermore, the signal acquisition unit 113 according to this embodiment acquires signal waveform information indicating the waveform of the detection signal output from the proximity sensor 55 when the workpiece holding unit 32 is rotated in a state in which the head 5 is moved so that the proximity sensor 55 faces the side of the workpiece W after cutting the workpiece W. Then, the determination unit 114 determines the presence or absence of broken pieces of the tool 20 attached to the workpiece W based on the signal waveform information acquired from the proximity sensor 55. This makes it possible to detect the adhesion of broken pieces generated when the tool 20 breaks to the workpiece W. Therefore, for example, it is possible to prevent a workpiece W with a processing defect due to breakage of the tool 20 from flowing out to a process subsequent to the process in which the cutting process is performed.

[0041] In the cutting processing device 1 according to this embodiment, the workpiece holding section 32, the tool holding section 33, and the chuck 53 are disposed inside the interior case 13, the first cover 141 closes the gap between the head 5 and the outer periphery of the opening 13a in the interior case 13, and the second cover 142 closes the gap between the holding unit 3 and the outer periphery of the opening 13b in the interior case 13. In addition, the tool holding section 33 is fixed to the unit body 31 such that, when the tool 20 is not inserted inside, the inside communicates with the outside of the unit body 31 of the holding unit 3 and the outer wall of the tool holding section 33 is isolated from the outside of the unit body 31. This allows a machining area S1 for performing cutting processing to be formed inside the interior case 13, which is isolated from the outside of the interior case 13, and prevents foreign matter present outside the interior case 13 from entering the machining area S1.

[0042] Although the embodiment of the present invention has been described above, the present invention is not limited to the configuration of the above-mentioned embodiment. For example, as shown in Fig. 10, the holding unit may have a proximity sensor 2034 arranged in the vicinity of a portion of the tool holding section 33 where the blade section 21 of the tool 20 is stored. In this case, the control section may have a type identification section that identifies the type of the blade section 21 of the tool 20 based on a detection signal output from the proximity sensor 2034 when the tool 20 is held by the tool holding section 33, and a type determination section that determines whether or not the type of the tool 20 identified by the type identification section matches the type of the tool 20 to be held that is set in advance for each of the tool holding sections 33.

[0043] According to this configuration, the occurrence of mistakes in setting the tool 20 on the tool holding portion 33 can be suppressed.

[0044] In the embodiment, the cutting device 1 may be configured to move the head 5 to a position where the workpiece W faces the proximity sensor 55 of the head 5 immediately before starting the processing step, acquire signal waveform information while rotating the workpiece W, and identify the shape of the workpiece W held by the workpiece holding part 32 based on the acquired signal waveform information. Then, the cutting device 1 may be configured to identify the type of tool 20 to be used in the processing step based on the identified shape of the workpiece W.

[0045] Although the embodiment and the modified examples of the present invention have been described above, the present invention is not limited to these. The present invention includes appropriate combinations of the embodiment and the modified examples, and appropriate modifications thereto. [Industrial Applicability]

[0046] The present invention is suitable as a cutting device for cutting bones. [Explanation of symbols]

[0047] 1: cutting processing device, 3: holding unit, 5: head, 10: housing, 10b, 13a, 13b, 54a: opening, 11: display panel, 12: support member, 13: interior case, 15: door, 20: tool, 21: blade, 31: unit body, 32: workpiece holding section, 33: tool holding section, 34, 55, 2034: proximity sensor, 41: base, 43: bracket, 44: lifting drive section, 51: spindle drive section, 52: rotating spindle, 53: chuck, 54: head cover, 71: X-direction drive section, 76: Y-direction drive section, 81, 86: rotation drive section, 82: shaft, 100: control section, 101: CPU unit, 102: main memory section, 103: auxiliary memory section , 105: input section, 104, 106: interface, 107a, 107b, 107c, 107d, 107e, 107f, 107g: drive circuit, 109: bus, 111: head control section, 112: holding unit control section, 113: signal acquisition section, 114: determination section, 115: notification section, 121: signal waveform storage section, 131: reference signal waveform storage section, 141: first cover, 142: second cover, 311: first part, 312: second part, 341, 551: sensor section, 342, 552: signal output section, 421, 721, 771: rail, 422, 722, 772: slider, JB: B axis, JC: C axis, S1: machining area, S2: area, W: work

Claims

1. a head having a spindle drive unit that rotates a rotating spindle having a tool fixed to a tip end thereof; A first proximity sensor; a signal acquiring unit that acquires detection signal information indicating a magnitude of a detection signal output from the first proximity sensor when the rotating spindle is rotated in a state in which the head is moved so that the first proximity sensor faces a side of the tool before and after cutting a workpiece using the tool; and a determination unit that determines whether or not the tool is broken based on the presence or absence of a difference in signal waveforms corresponding to a time transition of the magnitude of the detection signal indicated by each of the detection signal information acquired before and after the cutting process; and A holding unit including a workpiece holding portion that holds the workpiece and a rotation drive portion that rotates the workpiece holding portion; a second proximity sensor disposed on the head, the signal acquisition unit acquires a signal waveform of a detection signal output from the second proximity sensor when the workpiece holding unit is rotated in a state in which the head is moved so that the second proximity sensor faces a side of the workpiece after cutting processing of the workpiece using the tool, The determination unit determines whether or not there is a broken piece of the tool attached to the workpiece based on a signal waveform acquired from the second proximity sensor after the cutting process. Cutting equipment.

2. The holding unit further has a unit body that supports the workpiece holding portion with the workpiece holding portion exposed to the outside, The first proximity sensor is disposed inside the unit body. The cutting device according to claim 1 .

3. the head is cylindrical and has a bottom wall with an opening through which the rotating spindle is inserted, and further has a head cover in which the spindle drive unit is disposed, The second proximity sensor is disposed inside the head cover. The cutting device according to claim 1 or 2.

4. a head having a spindle drive unit that rotates a rotating spindle having a tool fixed to a tip end thereof; A first proximity sensor; a signal acquiring unit that acquires detection signal information indicating a magnitude of a detection signal output from the first proximity sensor when the rotating spindle is rotated in a state in which the head is moved so that the first proximity sensor faces a side of the tool before and after cutting a workpiece using the tool; and a determination unit that determines whether or not the tool is broken based on the presence or absence of a difference in signal waveforms corresponding to a time transition of the magnitude of the detection signal indicated by each of the detection signal information acquired before and after the cutting process; and A holding unit including a workpiece holding portion that holds the workpiece and a unit body that supports the workpiece holding portion in a state where the workpiece holding portion is exposed to the outside; an inner case having a peripheral wall formed with a first opening through which the head is inserted and a second opening through which the holding unit is inserted, and in which the workpiece holding portion and the tool are disposed; a first cover formed of a soft material and closing a gap between the head and an outer periphery of the first opening of the interior case; a second cover formed from a soft material and closing a gap between the holding unit and an outer periphery of the second opening of the interior case, The first proximity sensor is disposed inside the unit body. Cutting equipment.

5. an inner case having a peripheral wall formed with a first opening through which the head is inserted and a second opening through which the holding unit is inserted, and in which the workpiece holding portion and the tool are disposed; a first cover formed of a soft material and closing a gap between the head and an outer periphery of the first opening of the interior case; a second cover formed from a soft material and closing a gap between the holding unit and an outer periphery of the second opening in the interior case; The cutting device according to claim 3.

6. a head having a spindle drive unit that rotates a rotating spindle having a tool fixed to a tip end thereof; A holding unit including a workpiece holding portion that holds a workpiece and a rotation drive portion that rotates the workpiece holding portion; A second proximity sensor disposed on the head; a signal acquiring unit that acquires detection signal information indicating a magnitude of a detection signal output from the second proximity sensor when the workpiece holder is rotated in a state in which the head is moved so that the second proximity sensor faces a side of the workpiece before and after cutting processing of the workpiece using the tool; and and a determination unit that determines whether or not there is a broken piece of the tool attached to the workpiece based on a signal waveform corresponding to a time transition of a magnitude of the detection signal indicated by each of the detection signal information acquired from the second proximity sensor after the cutting process. Cutting equipment.

Images