MACHINE TOOL, MACHINING SYSTEM AND ADDITIONAL TABLE UNIT

Abstract

Machine tool (1), comprising: a rotary table (6) on which a workpiece (W) to be machined is attached; a motor (31) which rotates the rotary table (6); a brake (41) which places the rotary table (6) in a locking state or a release state; a valve (46a, 47a) which controls fluid supplied from a fluid supply source (100) to the brake (41) in order to place the brake (41) in the locked or released state; and a control unit (60) which controls the motor (31) and the valve (46a, 47a), wherein the control unit (60) determines, on the basis of a signal indicating a pressure inadequacy from a pressure switch (111) of a regulator (110) provided between the fluid supply source (100) and the valve (46a, 47a), that a rotation of the rotary table (6) by the motor (31) should not be carried out.

Description

{Technical field}

[0001] The present invention relates to a machine tool, a machining system and an additional table unit. {State of the art}

[0002] Traditionally, machine tools are known in which a workpiece is mounted on a rotary table and machining is performed on the workpiece while the rotary table's position is changed by a servo motor. Such a technique is described, for example, in PTL 1. This type of machine tool has a brake, actuated by compressed air, to hold the rotary table in a predetermined detent position (stop position).

[0003] DE 10 2018 120 934 A1 discloses a method for controlling a rotary table device in which a clamping mechanism drive unit is controlled to release the clamping of a brake disc. Subsequently, the pressure of the working fluid supplied to a clamping release fluid chamber is reduced, and a motor drive unit is controlled to rotate a motor. The degree of wear of the piston and the clamping element is then calculated based on a reference pressure and a pressure that occurs when the load torque of a spindle exceeds a reference load torque.

[0004] DE 10 2009 025 930 A1 discloses a device and a method for producing shapes composed of circular segments and straight sections. A rotary table is arranged on a cross table, and the workpiece is mounted on the rotary table. By operating adjusting spindles on the cross table and rotary table, the workpieces can be moved relative to the horizontally stationary milling tool such that circles or circular segments are produced by rotating the rotary table, and straight milling sections with different angles are produced by moving the workpiece using the cross table. {Bibliography}{Patent Literature}

[0005] [PTL 1] Japanese unexamined patent application JP 2015-155144 A [Brief description of the invention]{Technical problem}

[0006] If the brake is not properly supplied with air, unwanted wear and damage to the braking mechanism can occur. When unwanted wear and damage to the braking mechanism occur, the holding force in each detent position is reduced, which impairs the machining accuracy of the workpiece. For example, if the holding force is reduced, the rotary table can shift during machining operations.

[0007] If, for example, the air pressure for the brake is low, the servo motor can rotate the turntable while the brake is engaged, even though the brake is not fully released. In such a condition, undesirable wear occurs on the brake mechanism.

[0008] In view of the circumstances described above, the object of the invention is to provide a machine tool and a machining system as well as a table unit, each of which is able to avoid undesirable wear of a braking mechanism. {Solution to the problem}

[0009] The problem is solved by a machine tool comprising: a rotary table on which a workpiece to be machined is mounted; a motor which rotates the rotary table; a brake which places the rotary table in a locking or a release state; a valve which controls fluid supplied to the brake from a fluid supply source in order to place the brake in the locking or release state; and a control unit which controls the motor and the valve, wherein the control unit determines, on the basis of a signal indicating a pressure deficiency from a pressure switch of a regulator provided between the fluid supply source and the valve, that the rotary table should not be rotated by the motor.

[0010] The task is further solved by a machining system comprising: a plurality of machine tools and a management computer which manages the machine tools, each of the machine tools comprising: a rotary table on which a workpiece to be machined is mounted; a motor which rotates the rotary table; a brake which places the rotary table in a locking or a release state; a valve which controls fluid supplied from a fluid supply source to the brake in order to place the brake in the locking or release state;and a control unit that controls the motor and the valve, wherein the control unit determines, on the basis of a signal from a pressure switch of a regulator provided between the fluid supply source and the valve, whether or not a rotation of the rotary table should be carried out by the motor, wherein the management computer, on the basis of information of a machining status received from the machine tools, requests some of the machine tools to change the time specification of the machining operation if it is determined that there is a period in which a quantity of fluid used exceeds a predetermined criterion.

[0011] The problem is further solved by an additional table unit mounted on an XY table of a machine tool, the additional table unit comprising: a rotary table on which a workpiece to be machined is attached; a motor which rotates the rotary table; a brake which places the rotary table in a locking or a release state; a valve which controls fluid supplied from a fluid supply source to the brake in order to place the brake in the locking or release state; and a controller which controls the motor and the valve, wherein the controller determines, on the basis of a signal indicating a pressure insufficientness from a pressure switch of a regulator provided between the fluid supply source and the valve, that the rotary table should not be rotated by the motor.

[0012] Furthermore, the task is solved by a machining system comprising: a plurality of machine tools; and a management computer which manages the machine tools, each of the machine tools comprising: an additional table unit which is mounted on an XY table of a machine tool, the additional table unit comprising: a rotary table on which a workpiece to be machined is mounted; a motor which rotates the rotary table; a brake which places the rotary table in a locking or a release state; a valve which controls fluid supplied from a fluid supply source to the brake in order to place the brake in the locking or release state;and a control unit that controls the motor and the valve, wherein the control unit determines, based on a signal from a pressure switch of a regulator provided between the fluid supply source and the valve, whether or not a rotation of the rotary table should be carried out by the motor, wherein the management computer, based on information of a machining status received from the machine tools, requests some of the machine tools to change the time specification of the machining operation if it is determined that there is a period in which a quantity of fluid used exceeds a predetermined criterion. {Brief description of the drawings} { Fig. 1} Fig. Figure 1 is a schematic perspective view of a machine tool according to an embodiment of this invention. { Fig. 2} Fig. Figure 2 is a schematic perspective view of a table unit of the machine tool of this embodiment. { Fig. 3} Fig. Figure 3 is a diagram that represents an internal structure of a second support section of this embodiment. { Fig. 4} Fig. 4 is a block diagram of a control system for the machine tool of this embodiment. { Fig. 5} Fig. Figure 5 is a flowchart which illustrates an example of the processing by the control system of this embodiment. { Fig. 6} Fig. Figure 6 is a graph which represents an operating example of the machine tool of this embodiment. { Fig. 7} Fig. Figure 7 is a flowchart which illustrates an example of the processing by the control system of this embodiment. { Fig. 8} Fig. Figure 8 is a schematic diagram of a machining system comprising the machine tool of this embodiment and a management computer. {Description of embodiments}

[0013] A machine tool 1 according to one embodiment is now described below with reference to the drawings.

[0014] The machine tool 1 according to this embodiment comprises, as shown in Fig. Figure 1 shows a main body 1a of a machine tool, comprising a base 2 and a column section 3 extending upwards from the base 2, a spindle unit 4 supported by the column section 3 in such a way that the spindle unit 4 is movable in an upward and downward direction, and a table unit (movement mechanism) 5 supporting a workpiece W. A tool magazine (not shown), adapted for the automatic changing of tools T to be mounted on a spindle 4a of the spindle unit 4, may be provided on the spindle unit 4.

[0015] Base 2 is installed at the location where machine tool 1 is used, using, for example, a leveling screw, an anchor screw, or the like. As shown in Fig. As shown in Figure 2, the table unit 5 is arranged on the base 2, and the workpiece W is attached to the first rotary table 6 of the table unit 5 by any suitable fastening means. The first rotary table 6 and the workpiece W are adapted to move relative to the spindle 4a in an X-axis direction, a Y-axis direction, about the X-axis, and about an axis extending in an upward and downward direction by means of a plurality of servomotors 13, 23, 31, and 32 provided on the table unit 5, which will be described later. The spindle 4a and a spindle head 4b of the spindle unit 4 are arranged above the table unit 5.

[0016] The tool T is a section which is adapted to be brought into contact with the workpiece W for the purpose of machining the workpiece W and is, for example, a tool of any suitable type, such as drills, taps, milling cutters, polishing tools, etc.

[0017] The spindle head 4b rotatably supports the spindle 4a, and a spindle motor 5a, adapted to rotate the spindle 4a, is attached to an upper end of the spindle head 4b. The spindle head 4b is further supported by the column section 3 of the machine tool main body 1a in such a way that the spindle head 4b is movable in the upward and downward directions.

[0018] In particular, a plurality of guide rails 3a extending in a vertical direction (Z-axis direction) are provided on the stator section 3, and the spindle head 4b is supported by the guide rails 3a to be movable in the vertical direction. A Z-axis motor 3b is furthermore attached to the upper end of the stator section 3, and the output from an output shaft of the Z-axis motor 3b is transmitted via a delay element 3c and the like to a ball screw 3d. The ball screw 3d is arranged along the guide rails 3a and is threaded into a ball screw nut attached to the rear surface section 4c of the spindle head 4b. This feature allows the spindle unit 4 to move in the vertical direction by means of the rotation of the output shaft of the Z-axis motor 3b.

[0019] As it is in Fig. As shown in Figure 2, a plurality of guide rails 11, extending in the Y-axis direction (a horizontal direction), are provided on an upper surface section of the base 2. A section 12, movable in the Y-direction, is supported by the guide rails 11 to enable movement in the Y-axis direction. A Y-axis motor 13 is also attached to the upper end of the base 2, and the output from an output shaft of the Y-axis motor 13 is transmitted via a delay element 13a and the like to a ball screw 14. The ball screw 14 is arranged along the guide rails 11 and is threaded into a ball screw nut, which is part of the section 12 movable in the Y-direction. This feature allows the section 12, which is movable in the Y direction, to move in the Y-axis direction by means of the rotation of the output shaft of the Y-axis motor 13.

[0020] As it is in Fig. As shown in Figure 2, a plurality of guide rails 21, extending in the X-axis direction (a horizontal direction), are provided on an upper surface section of the Y-direction movable section 12. An XY table 22 is supported by the guide rails 21 to be movable in the X-axis direction. An X-axis motor 23 is also attached to the upper surface section of the Y-direction movable section 12, and the output from an output shaft of the X-axis motor 23 is transmitted via a delay element 23a and the like to a ball screw 24. The ball screw 24 is arranged along the guide rails 21 and is threaded into a ball screw nut, which is part of the XY table 22. This feature allows the XY table 22 to move in the X-axis direction by means of the rotation of the output shaft of the X-axis motor 23.

[0021] Due to the feature described above, the XY table 22 moves relative to the spindle 4a in the X-axis direction and the Y-axis direction.

[0022] The XY table 22 is typically a table to which the workpiece W is attached, or a clamping device used to secure the workpiece W. A plurality of grooves 22a are provided on the upper surface of the XY table 22, and these grooves 22a are used to secure the workpiece W or the clamping device for securing the workpiece W. For example, the groove 22a has an upper end whose width is less than that of the lower section of the groove 22a. A screw, inserted into the workpiece W or the clamping device, is screwed into a receiving part located in the groove 22a, thereby securing the workpiece W or the clamping device for securing the workpiece W to the XY table 22.

[0023] In a case where the workpiece W or the clamping device for securing the workpiece is attached to the XY table 22, the machine tool 1 moves the tool T in the upward and downward directions by the Z-axis motor 3b, while the workpiece W is moved in the X-axis and Y-axis directions by the X-axis motor 23 and Y-axis motor 13. As a result, a predefined machining operation is performed on the workpiece W.

[0024] In this embodiment, an additional table unit AU is attached to the XY table 22. The additional table unit AU is designed to rotate the workpiece about the X-axis and about an axis extending in an upward and downward direction, in addition to the movement in the X-axis and Y-axis directions.

[0025] The additional table unit AU has a first support section 30 attached to the XY table 22 and a second support section 40 attached to the XY table 22. As shown in Fig. 1 and Fig. As shown in Figure 2, the first support section 30 and the second support section 40 can be connected to each other by a plate-like connecting element. When the aforementioned fastening is carried out, the first support section 30 and the second support section 40 are aligned in the X-axis direction. Screws, for example, which have been inserted into a portion of the first support section 30 and the second support section 40 to extend through it, are screwed into a receiving part arranged in the groove 22a, thereby fastening the first support section 30 and the second support section 40 to the XY table 22.It should be noted that in a case where the first support section 30 and the second support section 40 are aligned in the Y-axis direction, when the aforementioned fastening is carried out, the additional table unit AU will rotate the workpiece W about the Y-axis and about the axis extending in the upward and downward direction.

[0026] The additional table unit AU comprises a first rotary table 6, which is supported by the first support section 30 and the second support section 40. The first rotary table 6 has a shaft 51, supported by the first support section 30 to allow rotation about the X-axis, a shaft 52, also supported by the second support section 40 to allow rotation about the X-axis, and a plate element 53, both ends of which are attached to shafts 51 and 52, respectively. The first additional shaft motor 31 is attached to the first support section 30, and the output shaft of the first additional shaft motor 31 is directly attached to shaft 51. In other words, the rotational force of the first additional shaft motor 31 is transmitted to shaft 51 without the engagement of a gear, a retarder, or the like. Such a mechanism is sometimes called a direct drive.

[0027] A second rotary table 54 is provided on the plate element 53, and the second rotary table 54 is supported by the plate element 53 so that it can rotate about an axis extending in a direction perpendicular to the X-axis. A second additional shaft motor 32 is attached to the plate element 53, and an output shaft of the second additional shaft motor 32 is directly attached to the mounting unit 54. In other words, the rotational force of the second additional shaft motor 32 is transmitted to the second rotary table 54 without the engagement of a gear, a delay element, or the like. The structure is also a direct drive mechanism.

[0028] Inside the second support section 40, a brake 41 is provided for stopping the rotation of the first rotary table 6. In this embodiment, the brake 41 is designed to stop the rotation of the shaft 52 by frictional force; however, it can also be a brake of any other type.

[0029] Fig. Figure 3 shows the structure of the brake 41. The brake 41 of this embodiment has a locking element 42 attached to the housing 40a of the second support section 40, a brake disc 43 attached to the shaft 52, a piston chamber 44 provided in the housing 40a and a piston 45 arranged inside the piston chamber 44 and movable in an axial direction of the shaft 52.

[0030] The piston chamber 44 has a locking chamber 44a, which is formed on the side of the piston 45 away from the brake disc 43, and a release chamber 44b, which is formed on the side of the piston 45 close to the brake disc 43.

[0031] The brake 41 has a fluid channel 46, one end of which is connected to the locking chamber 44a and the other end of which is open on the outside of the housing 40a, and a valve 46a, such as a solenoid valve, which is mounted at the other end of the fluid channel 46. The brake 41 further has a fluid channel 47, one end of which is connected to the release chamber 44b and the other end of which is open on the outside of the housing 40a, and a valve 47a, such as a solenoid valve, which is mounted at the other end of the fluid channel 47.

[0032] The brake 41 also has a metal spring 48, such as a disc spring, which preloads the piston 45 in the aforementioned axial direction and in the direction away from the brake disc 43 and the locking element 42.

[0033] As it is in Fig. As shown in Figure 3, valve 46a and valve 47a are connected to compressor 100, which is a fluid supply source, via a regulator 110. When air (fluid) is supplied from compressor 100 to the locking chamber 44a via pipe 101 and fluid channel 46, piston 45 is moved against spring 48 towards the side of the brake disc 43. This results in the outer circumferential section of the brake disc 43 being held and clamped between piston 45 and locking element 42, and the shaft 52 being locked by friction.

[0034] However, when air is supplied from compressor 100 via pipe 101 and fluid channel 47 to release chamber 44b, piston 45 is moved away from brake disc 43. This results in shaft 52 being placed in a released state.

[0035] An air supply bore 49 is provided in the housing 40a, and one end of the air supply bore 49 opens into the space on the outer side in the radial direction of the shaft 52, and this space is located inside the housing 40a. The other end of the air supply bore 49 is also open at one end of the housing 40a, and the valve 49a, such as a solenoid valve, is mounted at the other end. The valve 49a is connected to the compressor 100 via the regulator 110. When the valve 49a is open, air from the compressor 100 is supplied to the interior of the housing 40a and escapes through a gap in the housing 40a. The valve 49a is controlled by a control unit 60, which will be described later. The escaping air prevents cutting oil, cutting debris, etc., from entering the interior of the housing 40a. Air to prevent the ingress of cutting oil, cutting debris, etc.is also supplied to other sections of the first support section 30, the spindle unit 4, etc.

[0036] It should be noted that the controller 110 adjusts the pressure of the air from the compressor 100 to a pressure suitable for use in the machine tool 1. The controller 110 has a known pressure switch 111. If the pressure of the air from the compressor 100 is equal to or greater than a predetermined setpoint, the pressure switch 111 periodically or continuously sends a pressure satisfaction signal to the controller 60, which will be described later, indicating that the pressure is equal to or greater than the setpoint. If the pressure of the air from the compressor 100 is lower than the predetermined setpoint, the pressure switch 111 periodically or continuously sends a pressure inadequacy signal to the controller 60, indicating that the pressure is lower than the setpoint.

[0037] It should be noted that the spring 48 can be designed to bias the piston 45 towards the side of the brake disc 43. In this case, the spring 48 can be located on the side of the piston 45 away from the brake disc 43. If this feature is used, the piston 45 is pressed against the brake disc 43 by the spring 48, and the shaft 52 is held in a locked position as long as no air is supplied to the release chamber 44b.

[0038] The clamping device J for securing the workpiece is attached to the second rotary table 54, and the workpiece W is attached to the clamping device J. The workpiece W can also be attached directly to the second rotary table 54.

[0039] It should be noted that the additional table unit AU can be removed from the XY table 22 as needed. In some cases, the removal and installation can be carried out by a user of machine tool 1.

[0040] In a case where the additional table unit AU is mounted on the XY table 22 and the clamping device J or the workpiece W is attached to the second rotary table 54 of the additional table unit AU, the machine tool 1 can rotate the workpiece W not only in the X-axis and Y-axis directions, but also about the X-axis and about an axis extending in the upward and downward directions. This feature enables sophisticated and precise machining of the workpiece W.

[0041] The spindle motor 5a, the Z-axis motor 3b, the Y-axis motor 13, the X-axis motor 23, the first additional shaft motor 31, and the second additional shaft motor 32 are servo motors, such as synchronous motors. It should be noted that these motors may be servo motors other than synchronous motors.

[0042] The spindle motor 5a, the Z-axis motor 3b, the Y-axis motor 13, the X-axis motor 23, the first additional shaft motor 31 and the second additional shaft motor 32 each have an operating position detection device, such as a pulse generator, and the detection results of the operating position detection device are sent to the control 60 of the machine tool 1.

[0043] The spindle motor 5a, the Z-axis motor 3b, the Y-axis motor 13, the X-axis motor 23, the first additional shaft motor 31 and the second additional shaft motor 32 are connected to the control 60 of the machine tool 1 and the control 60 controls these motors 5a, 3b, 13, 23, 31 and 32.

[0044] The control unit 60 includes, as it is described in Fig. Figure 4 shows a processor 61, which includes a CPU and the like; a display device 62, such as a liquid crystal display device; a memory unit 63, which includes non-volatile memory, ROM, RAM, etc.; servo controllers 64a, 64b, 64c, 64d, 64e, and 64f, which correspond to the spindle motor 5a, the Z-axis motor 3b, the Y-axis motor 13, the X-axis motor 23, the first additional shaft motor 31, and the second additional shaft motor 32, respectively; an input unit 65, such as a control panel; and a transmitter and receiver unit 66 and a loudspeaker 67. In a case where the display device 62 has a touchscreen function, the display device 62 also functions as the input unit.

[0045] The input unit 65 can be a portable control panel, a tablet computer, etc. In these cases, the entire display unit 62 or a part thereof will be provided in the input unit 65. The display unit 62 can be provided as a separate unit distinct from the controller 60.

[0046] A system program 63a is stored in memory unit 63 and is responsible for the basic functionality of the control 60. Furthermore, a plurality of machining programs 63b, designed according to the workpiece W, and a brake control program 63d are stored in memory unit 63. The brake control program 63c can be a program or a set of instructions contained in the machining program 63b.

[0047] The control unit 60 sends control commands, control signals, and the like to the servo controllers 64a, 64b, 64c, 64d, 64e, and 64f, according to the instruction set of the machining program 63b. The control unit 60 also sends control commands, control signals, and the like to the valves for the machining program 63b, based on the brake control program 63c, at a predetermined time. Consequently, while the shaft 52 is being moved into a locked or unlocked state at a predetermined time, the control unit 60 brings the tool T, rotated by the spindle motor 5a, into contact with the workpiece W, which moves in the X-axis direction, the Y-axis direction, about the X-axis, and about the axis extending in the upward and downward directions. This results in machining being performed on the workpiece W.

[0048] The control unit 60 of this embodiment determines, based on the signal from the pressure switch 111 of the controller 110, whether the rotation of the first rotary table 6 should be carried out by the first additional shaft motor 31 or not. An example of the operation by the control unit 60 is shown with reference to the flowchart of Fig. 5 and the graph of Fig. 6 described.

[0049] Before the control process begins, the first rotary table 6 is in a locked state. When a predetermined time is reached at which the first rotary table 6 should be rotated (step S1-1), the control unit 60 then closes valve 46a and opens valve 47a based on the brake control program 63c to release the first rotary table 6 (step S1-2). Furthermore, when the control unit 60 receives the aforementioned pressure satisfaction signal from the pressure switch 111 (step S1-3), it rotates the first rotary table 6 until it reaches, for example, a first command position, which is the next command position (step S1-4). At this point, the control unit 60 sends control commands, control signals, and the like to the servo controller 64e based on the machining program 63b.

[0050] Meanwhile, in step S1-3, when it receives the aforementioned pressure deficiency signal from the pressure switch 111, the control unit 60 determines that no rotation of the first rotary table 6 should take place (step S1-5).

[0051] The controller 60 executes the aforementioned control each time the specified time is reached. For example, if, as in Fig. As shown in Figure 6, when the aforementioned pressure deficiency signal is received by the pressure switch 111 at a control command input time for rotating the first rotary table 6, so that it reaches the second command position, the control unit 60 then performs the determination described above.

[0052] In this embodiment, as described in Fig. As shown in Figure 6, the setpoint of the pressure switch 111 is slightly smaller than the recommended pressure of the compressed air used in the brake 41.

[0053] It is possible that, in a state where the air pressure from compressor 100 is low, the piston 45 may not move sufficiently away from the brake disc 43, even if valve 47a is open. In this case, the first auxiliary shaft motor 31 may rotate the brake disc 43, along with the shaft 52 itself, in a state where the piston 45 is not moved away from the brake disc 43. This can lead to undesirable wear on the contact section between the piston 45 and the brake disc 43, the contact section between the locking element 42 and the brake disc 43, the brake disc 43 itself, and so on. This wear can result in a decrease in the locking force of the first rotary table 6 by the brake 41, an increase in the frequency of maintenance required for the brake 41, and similar issues. The aforementioned situation can lead to premature failure of the brake 41 mechanism.The locking force of the brake 41 or the performance of the mechanism significantly affects the quality of the workpiece W undergoing machining by the machine tool 1.

[0054] In this embodiment, the control unit 60 determines, based on the signal from the pressure switch 111, whether the rotation of the first rotary table 6 should be carried out by the first additional shaft motor 31 or not. For example, the control unit 60 does not allow the rotation of the first additional shaft motor 31 if the air pressure from the compressor 100, as indicated by the pressure switch 111, is lower than a predetermined setpoint. This feature is advantageous for preventing unintentional decreases in the locking force of the brake 41, maintaining the performance of the brake 41 mechanism, preventing unintentional increases in the number of brake 41 maintenance tasks, and the like. Furthermore, this feature is also advantageous for improving or maintaining the machining accuracy of the workpiece W.

[0055] It should be noted that control 60 is determined by the flowchart of Fig. 7. Control system shown, together with the control system of Fig. 5 or instead of controlling Fig. 5 can be carried out. As it is in Fig. As shown in Figure 7, the controller 60 determines, based on the pressure satisfaction signal received from the pressure switch 111 and the pressure inadequacy signal, whether the air pressure from the compressor 100 is lower than the aforementioned predefined setpoint for a period exceeding a predefined time (step S2-1). The predefined time can be several seconds or a dozen seconds or more. If the determination in step S2-1 results in "Yes", the controller 60 executes the predefined notification action (step S2-2).

[0056] The specified notification measure is, for example, the control of the display device 62 to display a specified screen on the display device 62, the control of the loudspeaker 67 to emit a specified tone from the loudspeaker 67, and the like.

[0057] This feature allows the operator of machine tool 1 to recognize that the air pressure from compressor 100 is unstable. This helps to prevent unintentional decreases in the locking force of brake 41, maintain the performance of the brake 41 mechanism, avoid unintentional increases in the number of brake 41 maintenance tasks, and the like. This feature is also advantageous for improving or maintaining the machining accuracy of workpiece W.

[0058] In step S2-1, the controller 60 can determine whether the pressure deficiency signal has been received a specified number of times or more during a specified period.

[0059] As it is in Fig. As shown in Figure 8, several machine tools 1 can be connected to a management computer 200, which can be used to design the machining system. The management computer 200 is a known computer that includes a processor, such as a CPU, a memory unit comprising RAM, ROM and non-volatile memory, a display device, an input device, such as a keyboard, touchscreen, etc., and a transmit and receive unit.

[0060] The management computer 200 receives individual components of a machining status information from the multiple controllers 60 of the machine tools 1. Machining status information includes, for example, details regarding the content of the machining program 63b being executed, which part of the machining program 63b is being executed, and similar information. Machining status information can also include details about when air from the compressor 100 is used and its applications. For example, the controller 60 of machine tool 1 receives information about when valve 46a and valve 47a for the brake 41 are opened, and information about when valve 49a is opened to prevent the ingress of cutting oil, cutting debris, etc.An example of information about timing is information about the times at which valves 46a, 47a and 49a are opened and closed.

[0061] The control unit 60 and the management computer 200 generally include a calendar function, and the times of their calendar functions are synchronized. This means that the management computer 200 recognizes the times at which, and the applications for which, the air is used in the individual machine tools 1.

[0062] In some cases, air from a single compressor is supplied to dozens, several tens, or several hundred or more machine tools 1. If, for example, at this point, valve 46a and valve 47a for the brake 41 are opened simultaneously in several dozen machine tools 1, the pressure of the air from compressor 100 is then expected to be lower than the aforementioned specified setpoint.

[0063] If, based on the aforementioned information, it has been determined that there is a period during which the amount of air used by the several machine tools 1 exceeds the specified criterion, the management computer 200 then requests some of the machine tools to change their machining operation. The request indicates, for example, that the time at which valve 46a and valve 47a are opened should be changed for some of the machine tools 1. For this change, the management computer 200 sends control signals to some of the machine tools 1 to change the time at which valve 46a and valve 47a are opened, or the time at which the machining program 63b is executed.This feature effectively prevents the air pressure from the compressor 100 from being equal to or lower than a predetermined criterion, and contributes to improving the machining accuracy of the workpiece W.

[0064] It should be noted that if a brake similar to the brake 41 is provided on the second additional shaft motor 32, the control 60 can determine in the same or a similar way as in the case of the first additional shaft motor 31 that no rotation should take place for the second additional shaft motor 32.

[0065] It should be noted that the additional table unit AU can be designed to include only the first additional shaft motor 31 or only the second additional shaft motor 32. If the additional table unit AU includes only the second additional shaft motor 32, the additional table unit AU then rotates the attached workpiece W and clamping device J about the axis that extends in the upward and downward directions. {List of reference symbols} 1 machine tool 1a Machine tool main body 2 Basis 3 Stand section 4 spindle unit 4a Spindle 4b Spindle head 5 Table unit (movement mechanism) 5a Spindle motor 6 first turntable 12 section movable in Y direction 13 Y-axis motor 22 XY table 22a Nut 23 X-axis motor 30 first carrying section 31 first additional shaft motor 32 second additional shaft motor 40 second carrying section 41 Brake 44 Piston chamber 45 pistons 46a, 47a Valve 51, 52 wave 53 plate elements 54 second turntable 60 Control 61 processor 62 Display unit 63 storage units 63a System program 63b Processing program 43c Brake Control Program 100 Compressor (fluid supply source) 110 controllers 111 Pressure switches 200 administrative computers T tool W workpiece J clamping device AU additional table unit (movement mechanism)

Claims

[1] Machine tool (1), comprising: a rotary table (6) on which a workpiece (W) to be machined is attached; a motor (31) which rotates the rotary table (6); a brake (41) which places the rotary table (6) in a locking state or a release state; a valve (46a, 47a) which controls fluid supplied from a fluid supply source (100) to the brake (41) in order to place the brake (41) in the locked or released state; and a control unit (60) which controls the motor (31) and the valve (46a, 47a), wherein the control unit (60) determines, on the basis of a signal indicating a pressure inadequacy from a pressure switch (111) of a regulator (110) provided between the fluid supply source (100) and the valve (46a, 47a), that a rotation of the rotary table (6) by the motor (31) should not be carried out. [2] Machine tool (1) according to claim 1, wherein the control (60) performs a predetermined notification when the control (60) determines, based on the signal from the pressure switch (111), that the pressure of the fluid from the fluid supply source (100) is lower than a setpoint of the pressure switch (111) for a period which exceeds a predetermined period, or when the control (60) determines that a condition in which the pressure is lower than the setpoint occurs for a predetermined number of times or more during a predetermined period. [3] Processing system, including: a plurality of machine tools (1); and an administrative computer (200) which manages the machine tools (1), each of the machine tools (1) comprising: a rotary table (6) on which a workpiece (W) to be machined is attached; a motor (31) which rotates the rotary table (6); a brake (41) which places the rotary table (6) in a locking state or a release state; a valve (46a, 47a) which controls fluid supplied from a fluid supply source (100) to the brake (41) in order to place the brake (41) in the locked or released state; and a control unit (60) which controls the motor (31) and the valve (46a, 47a), wherein the control unit (60) determines, on the basis of a signal from a pressure switch (111) of a regulator (110) provided between the fluid supply source (100) and the valve (46a, 47a), whether or not a rotation of the rotary table (6) should be carried out by the motor (31), wherein The administrative computer (200), based on information about the processing status received from the machine tools (1), requests some of the machine tools (1) to to change the time specification of the processing operation if it is determined that there is a period in which a quantity of fluid used exceeds a specified criterion. [4] Additional table unit (AU) mounted on an XY table (22) of a machine tool (1), the additional table unit (AU) comprising: a rotary table (6) on which a workpiece (W) to be machined is attached; a motor (31) which rotates the rotary table (6); a brake (41) which places the rotary table (6) in a locking state or a release state; a valve (46a, 47a) which controls fluid supplied from a fluid supply source (100) to the brake (41) in order to place the brake (41) in the locked or released state; and a control unit (60) which controls the motor (31) and the valve (46a, 47a), wherein the control unit (60) determines, on the basis of a signal indicating a pressure inadequacy from a pressure switch (111) of a regulator (110) provided between the fluid supply source (100) and the valve (46a, 47a), that a rotation of the rotary table (6) by the motor (31) should not be carried out. [5] Processing system, including: a plurality of machine tools (1); and an administrative computer (200) which manages the machine tools (1), each of the machine tools (1) comprising: an additional table unit (AU) which is mounted on an XY table (22) of a machine tool (1), wherein the additional table unit (AU) comprises: a rotary table (6) on which a workpiece (W) to be machined is attached; a motor (31) which rotates the rotary table (6); a brake (41) which places the rotary table (6) in a locking state or a release state; a valve (46a, 47a) which controls fluid supplied from a fluid supply source (100) to the brake (41) in order to place the brake (41) in the locked or released state; and a control unit (60) which controls the motor (31) and the valve (46a, 47a), wherein the control unit (60) determines, on the basis of a signal from a pressure switch (111) of a regulator (110) provided between the fluid supply source (100) and the valve (46a, 47a), whether or not a rotation of the rotary table (6) should be carried out by the motor (31), wherein The administrative computer (200), based on information about the processing status received from the machine tools (1), requests some of the machine tools (1) to to change the time specification of the processing operation if it is determined that there is a period in which a quantity of fluid used exceeds a specified criterion.

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