WO2024095680A1

WO2024095680A1 - Machine tool system, and method for controlling machine tool system

Info

Publication number: WO2024095680A1
Application number: PCT/JP2023/036305
Authority: WO
Inventors: 内山　拓治; 克宏篠宮; 武史池ケ谷
Original assignee: スター精密株式会社
Priority date: 2022-10-31
Filing date: 2023-10-05
Publication date: 2024-05-10
Also published as: TW202419176A; JP2024065253A

Abstract

Provided are a machine tool system and a method for controlling a machine tool system with which accidents are not liable to occur. A lathe system 1 for manufacturing a plurality of products from one elongate rod material W by repeating, a plurality of times, machining of a tip end part of the rod material W and cutting off of a machined part that has been machined, comprises: a main spindle 25 which, when re-gripping the rod material W, releases grasping of the rod material W, moves in a Z1 axis direction to a grasping position, and grasps the rod material W; a pusher 44 which moves together with the rod material W in the Z1 axis direction; and a grasping position determining unit 20a which, each time re-gripping occurs, calculates a number N of products that can be machined while the main spindle 25 maintains its grasp of the rod material W, on the basis of a position of the pusher 44, a set movable distance Zp of the main spindle 25 in the Z1 axis direction, and a machining material length L3 required to machine one product, and determines the grasping position corresponding to the number N of products.

Description

MACHINE TOOL SYSTEM AND METHOD FOR CONTROLLING MACHINE TOOL SYSTEM

The present invention relates to a machine tool system and a method for controlling the machine tool system that manufactures multiple products from a single long bar by repeatedly machining the tip of the bar and cutting off the machined portion.

　Conventionally, some machine tool systems include a processing device equipped with a spindle and a tool rest, and a material feeder that supplies long bar stock to the processing device. The spindle of the processing device grips and rotates the bar stock in a releasable manner. The spindle is configured to be able to move in the axial direction of the bar stock whether it is gripping the bar stock or releasing the grip. A first control device is incorporated in the processing device. The first control device controls the operation of the tool rest, spindle, etc. according to a processing program (NC program) created by an operator of the machine tool system, etc., and input operations using an operation panel provided on the processing device. The first control device controls the operation of the tool rest and spindle according to the processing program, so that the tip of the bar stock is machined into the desired shape, and the machined portion is cut off.

The material feeder is installed alongside the processing device, closer to the rear end of the bar than the processing device. The material feeder is equipped with a feed arrow, a feed arrow drive mechanism for moving the feed arrow in the axial direction of the bar, and a second control device for controlling the operation of the feed arrow drive mechanism. The feed arrow is equipped with a finger chuck at its tip. The finger chuck grips the rear end of the bar, connecting the feed arrow to the bar. The feed arrow is then sent out towards the tip of the bar by the feed arrow drive mechanism, so that the bar fed into the material feeder is supplied to the processing device. When the processing device is performing processing, the feed arrow urges the bar from the rear end towards the tip of the bar with a predetermined load. This load is set to a relatively weak load that does not cause slippage between the bar and the spindle when the spindle is gripping the bar.

In a typical processing device, the bar is re-gripped after the machined portion is cut off. In the re-gripping, the spindle releases its grip on the bar and moves to the rear end of the bar, and then the spindle re-gripping the bar. By repeating multiple cycles of machining with a processing tool, cutting off the machined portion, and re-gripping the bar, a number of products are manufactured from one bar according to the number of cycles. In response to this, a machine tool system has been proposed that can process multiple products while the spindle maintains its grip on the bar by adjusting the gripping position of the spindle during re-gripping (see, for example, Patent Document 1). In the machine tool system of Patent Document 1, the length of the bar is measured when the bar is supplied, and the effective machining length of the bar that can be processed into products is calculated from the measurement result. Then, based on the effective machining length and the length of the bar required to process one product, the gripping position at which the spindle can process multiple products while maintaining its grip on the bar during re-gripping is determined in advance for all of the effective machining lengths. According to the machine tool system of Patent Document 1, the number of times the workpiece is regripped is reduced, which shortens the time required for tasks other than machining, such as the time required to release and regrip the spindle during regripping, and the time required to increase and decrease the spindle rotation speed, thereby increasing the productivity of the machine tool system.

Japanese Patent Application Laid-Open No. 06-218603

However, after the material feeder supplies the bar material to the processing device, when the machine tool system is temporarily stopped or when the machine tool system is stopped due to a power outage or emergency stop, the operator may manually operate the feed arrow to advance the bar material. In such cases, in the machine tool system of Patent Document 1, the positions of the bar material and the feed arrow will differ from those calculated, and there is a risk of an accident occurring in which the spindle grips the feed arrow during re-gripping, damaging the feed arrow or damaging the spindle.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a machine tool system and a control method for a machine tool system that are less prone to accidents.

The machine tool system of the present invention which solves the above problems comprises:
A machine tool system for manufacturing a plurality of products from a single bar by repeatedly machining a tip portion of a long bar and cutting off the machined portion, comprising:
a main shaft that, when re-gripping the bar material, releases the grip of the bar material and moves along the axial direction of the bar material to a gripping position to grip the bar material;
A feed arrow moving in the axial direction together with the bar;
The present invention is characterized in that it is provided with a gripping position determination unit that calculates, for each gripping, the number of products that can be processed while the spindle maintains its grip on the bar stock based on the position of the feed arrow, the distance the spindle can move in the axial direction, and the length of the workpiece required to process one of the products, and determines the gripping position corresponding to the number of products.

In this machine tool system, the gripping position determination unit determines the gripping position for each gripping operation, so even if the operator manually moves the bar, it is possible to prevent accidents such as the spindle gripping the feed arrow during gripping and damaging the feed arrow or the spindle being damaged.

Here, the spindle may grip the bar during machining and move forward along the axial direction of the bar.

In this machine tool system,
The machine may further include a continuous machining feasibility determination unit that determines, for each of the products being machined, whether or not the next product can be machined while the spindle continues to grip the bar stock.

With this machine tool system, the continuous machining feasibility determination unit makes the determination, so that even if an operator manually moves the feed arrow and the bar while the spindle is still gripping the bar and machining a number of products, it is possible to prevent accidents caused by the feed arrow and the bar being out of position or problems such as manufacturing products with incorrect lengths.

Here, the continuous machining feasibility determination unit may determine whether the next product can be machined while the spindle continues to grip the bar material prior to machining the next product. The continuous machining feasibility determination unit may also determine whether the next product can be machined without the re-gripping for each product. Furthermore, the continuous machining feasibility determination unit may include a machine control unit that causes the spindle to continue to grip the bar material when it determines that the next product can be machined while the spindle continues to grip the bar material. In addition, the continuous machining feasibility determination unit may include a machine control unit that causes the re-gripping when it determines that the next product cannot be machined while the spindle continues to grip the bar material.

In addition, in this machine tool system,
The feed arrow position determining unit may be provided for determining whether or not the position of the feed arrow coincides with a theoretical position of the feed arrow obtained by calculation for each processing of the product.

In this machine tool system, the feed arrow position determination unit makes the determination, so that even if an operator manually moves the feed arrow and the bar while the spindle is still gripping the bar and machining multiple products, it is possible to prevent accidents caused by the feed arrow and the bar being out of position and to prevent defects such as the manufacture of products with incorrect lengths.

Here, the feed arrow position determination unit may make a determination after the machined portion has been separated and before the start of machining of the next product. Also, the theoretical position of the feed arrow may be a position calculated using the length of the workpiece. The feed arrow position determination unit may stop the machine tool system when it determines that the position of the feed arrow does not match the theoretical position of the feed arrow. Also, the feed arrow position determination unit may display a message indicating that the position of the feed arrow does not match the theoretical position of the feed arrow when it determines that the position of the feed arrow does not match the theoretical position of the feed arrow.

In addition, in this machine tool system,
The machining apparatus may further include a workpiece length calculation unit that calculates the length of the processed workpiece based on a movement distance of the main spindle in the axial direction in a machining program in which machining operations are described.

The operator does not need to input the workpiece length or data required to calculate the workpiece length, improving the operability of this machine tool.

In addition, in this machine tool system,
The gripping position determination unit may be capable of switching between a multiple-piece mode in which the gripping position determination unit determines the gripping position and performs the gripping change, and a single-piece mode in which the gripping change is performed each time one of the products is processed.

The ability to switch between multiple-piece mode and single-piece mode increases operator convenience.

Furthermore, in this machine tool system,
a back spindle disposed opposite the spindle and to which the machined portion is transferred;
a machining restricting portion that restricts machining of the bar held by the spindle until the back spindle is retracted to a safety position;
The safety position changer may change the safety position.

By changing the safety position to an appropriate position, the time during which the machining restriction unit restricts machining can be shortened, thereby increasing the productivity of the machine tool system.

Here, the machining regulating unit may regulate machining by regulating the execution of a machining program in which machining operations using the spindle are described, or may regulate machining by regulating the movement of the spindle.

A method for controlling a machine tool system according to the present invention that solves the above problems includes:
A method for controlling a machine tool system for manufacturing a plurality of products from a single bar stock by repeatedly machining a tip portion of the bar stock held by a spindle and cutting off the machined portion, comprising:
a gripping position determination step for calculating the number of products that can be machined while the spindle is still gripping the bar stock, based on the position of a feed arrow that moves in the axial direction of the bar stock together with the bar stock, the axial movement distance of the spindle, and the length of the workpiece required to process one of the products, and determining a gripping position corresponding to the number of products;
and a re-gripping step in which the spindle, which has released the grip of the bar material, moves to the gripping position determined in the gripping position determination step and grips the bar material again.

According to this control method for the machine tool system, the gripping position is determined in the gripping position determination process, so even if the operator manually moves the bar while the spindle is machining multiple products while still holding the bar, it is possible to prevent accidents such as the spindle gripping the feed arrow during re-gripping and damaging the feed arrow or the spindle being damaged.

The present invention provides a machine tool system and a method for controlling the machine tool system that are less prone to accidents.

FIG. 1 is a front view of a lathe system according to an embodiment of the present invention. FIG. 2 is a plan view showing a simplified internal configuration of the lathe system shown in FIG. 1 . FIG. 2 is a block diagram showing a hardware configuration of the lathe system shown in FIG. 1 . FIG. 2 is a functional block diagram showing a functional configuration of the lathe system shown in FIG. 1 . 2 is a flowchart showing the operation of the lathe system shown in FIG. 1 . 6 is a flowchart showing the gripping position determining operation shown in FIG. 5 . 7 is a plan view for explaining a positional relationship in the gripping position determining operation shown in FIG. 6 . FIG. 4 is a flowchart showing an operation of the lathe system shown in FIG. 1 in a single-piece mode. FIG. 5 is a functional block diagram similar to FIG. 4 , illustrating a functional configuration of a lathe system according to a second embodiment. 10 is a flowchart similar to FIG. 5 showing the operation of the lathe system shown in FIG. 9.

Below, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, the present invention will be described using an example in which it is applied to a lathe system equipped with an NC lathe and a material feeder.

FIG. 1 is a front view of the lathe system according to this embodiment.

As shown in FIG. 1, the lathe system 1 of this embodiment includes an NC lathe 2, which is a processing device, and a material feeder 4, which is a material supplying device. This lathe system 1 corresponds to an example of a machine tool system. The NC lathe 2 of this embodiment is a so-called Swiss-type lathe. The NC lathe 2 includes a cutting room 22, a spindle room 23, and a lathe operation panel 24. The cutting room 22 is a room in which a space is formed for machining the tip portion of the bar material W (see FIG. 2), and is located to the right of the NC lathe 2 when viewed from the front. The spindle room 23 is a room in which the spindle 25 (see FIG. 2) is located, and is located to the left of the NC lathe 2 when viewed from the front.

The lathe operation panel 24 has a lathe operation section 241 and a lathe display screen 242. The lathe operation section 241 is composed of a plurality of buttons and keys that accept input operations by the operator of the lathe system 1. The lathe operation section 241 may be a touch panel integrated with the lathe display screen 242. The operator of the lathe system 1 can store a machining program created using the lathe operation section 241 or an external computer in the storage section 203 (see FIG. 3) described later. The operator of the lathe system 1 can also use the lathe operation section 241 to modify the machining program and store the modified machining program in the storage section 203. The operator of the lathe system 1 can also use the lathe operation section 241 to operate each component of the lathe system 1 individually or in cooperation with each other. The lathe display screen 242 is a display that displays various information related to the lathe system 1, such as the machining program stored in the storage section 203, various setting values of the lathe system 1, and error contents.

The material feeder 4 supplies long bar material W (see Figure 2) to the NC lathe 2. The material feeder 4 is installed alongside the NC lathe 2. A plurality of bars W are stored in the material feeder 4. The material feeder 4 sends out one of the stored bars W towards the NC lathe 2. The material feeder 4 also pulls out and discharges the remaining bar material W, which is a bar material W that has been shortened by processing, from the NC lathe 2. After discharging the remaining bar material, the material feeder 4 sends out a new bar material W from the stored bar material W towards the NC lathe 2. The material feeder 4 is provided with a material feeder operation panel 42, which is an input device for operating the material feeder 4.

Figure 2 is a plan view showing a simplified internal configuration of the lathe system shown in Figure 1.

As shown in Figure 2, the NC lathe 2 is equipped with a spindle 25, a guide bush 26, a first tool rest 27, a back spindle 28, and a second tool rest 29. The spindle 25, guide bush 26, first tool rest 27, back spindle 28, and second tool rest 29 are placed on legs that serve as the base. The spindle 25, first tool rest 27, back spindle 28, and second tool rest 29 operate according to a machining program that describes machining operations and input from the lathe operation panel 24 (see Figure 1).

The spindle 25 can move in the Z1-axis direction. The spindle 25 moves in the Z1-axis direction together with the spindle head by the spindle stock, but the spindle stock is not shown and the description is also omitted. The Z1-axis direction is a horizontal direction, and is the left-right direction in FIG. 2. This Z1-axis direction corresponds to an example of the axial direction of the bar W. The spindle 25 has a collet chuck 251 at its tip for releasably gripping the bar W that penetrates its interior. The spindle 25 can grip the bar W and rotate around the spindle center line CL. The direction of the spindle center line CL coincides with the Z1-axis direction. Hereinafter, the movement of the spindle 25 toward the tip of the bar W may be referred to as forward movement, and the movement of the spindle 25 toward the rear end of the bar W may be referred to as backward movement. In FIG. 2, the right direction is the forward movement direction, and the left direction is the backward movement direction.

The guide bush 26 is fixed to the legs, which serve as the base. The end face of the guide bush 26 opposite to the side where the spindle 25 is arranged is exposed in the cutting chamber 22 (see FIG. 1). The guide bush 26 supports the tip portion of the bar W that penetrates the inside of the spindle 25 so that it can slide freely in the Z1 axis direction. The portion of the guide bush 26 that supports the bar W can rotate around the spindle center line CL in synchronization with the spindle 25. The tip portion of the bar W that protrudes from the guide bush 26 into the cutting chamber 22 is machined by a first tool T1 attached to a first tool rest 27. This first tool T1 corresponds to an example of a machining tool. The guide bush 26 suppresses bending of the bar W during machining, so that particularly long and thin bar W can be machined with high precision by the NC lathe 2.

The first tool rest 27 can move in the X1-axis direction, which is perpendicular to the Z1-axis direction and faces horizontally, and in the Y1-axis direction, which faces vertically. This first tool rest 27 corresponds to an example of a tool rest. In FIG. 2, the up-down direction is the X1-axis direction, and the direction perpendicular to the paper surface is the Y1-axis direction. On the first tool rest 27, multiple types of first tools T1, including cutting tools and cut-off tools, are attached in a comb-like shape lined up in the Y1-axis direction. Rotary tools such as end mills and drills can also be attached to the first tool rest 27 as the first tools T1. By moving the first tool rest 27 in the Y1-axis direction, an arbitrary first tool T1 is selected from these multiple types of first tools T1. Then, by moving the first tool rest 27 in the X1-axis direction, the selected first tool T1 cuts into the tip of the bar W held by the spindle 25 and supported by the guide bush 26 to process it, or cuts off the processed part of the bar W. The tool used to separate the machined parts is called a cut-off tool.

The back spindle 28 can move in the X2-axis direction and the Z2-axis direction. The back spindle 28 moves in the X2-axis direction and the Z2-axis direction together with the back spindle by the back spindle stock, but the back spindle stock is not shown and the description is omitted. The X2-axis direction is the same as the X1-axis direction described above, and the Z2-axis direction is the same as the Z1-axis direction described above. The Z2-axis direction corresponds to the axial direction of the back spindle 28. Figure 2 shows the back spindle 28 in a position facing the spindle 25 across the guide bush 26. In this position, the back spindle center line, which is the center of rotation of the back spindle 28, is arranged on the same line as the spindle center line CL. The direction of the back spindle center line coincides with the Z2-axis direction. The machined portion of the bar W that has been machined using the spindle 25 is cut off by a cut-off tool and transferred to the back spindle 28. Hereinafter, the machined portion that has been cut off is referred to as the cut portion. The rear spindle 28 holds the cut portion handed over from the spindle 25 in a releasable manner. The rear spindle 28 also moves in the X2-axis direction and the Z2-axis direction to transport the held cut portion.

The second tool rest 29 is movable in the Y2-axis direction. The second tool rest 29 may be configured to be movable in the X2-axis direction. The Y2-axis direction is the same direction as the Y1-axis direction described above. A second tool T2, such as a drill or an end mill, is attached to the second tool rest 29 to process the cut portion. A plurality of second tools T2 are attached to the second tool rest 29 in the Y2-axis direction. An arbitrary second tool T2 is selected from the plurality of second tools T2 by moving the second tool rest 29 in the Y2-axis direction. Then, the back spindle 28 moves in the X2-axis direction or the Z2-axis direction, so that the cut end side of the cut portion held by the back spindle 28 is processed. The cut portion after the processing of the cut end side becomes a product manufactured by the lathe system 1. There are also cases where the back spindle 28 is not used for processing. In that case, the cut portion becomes a product as it is. The second tool rest 29 is provided with a product receiving opening 291 for receiving the product and a shooter (not shown). The chute is provided inside the second tool rest 29. After the back spindle 28 inserts the product into the product receiving opening 291, it releases its grip and pushes it out using a cylinder provided on the back spindle 28, dropping the product into the chute. The dropped product is transported to a specified position by a conveyor (not shown) and discharged into a product storage section provided outside the lathe system 1.

The material feeder 4 has, in addition to the above-mentioned material feeder operation panel 42 (see FIG. 1), a feed arrow 44, a feed arrow drive mechanism 45, a feed arrow motor 46, a tip sensor 47, and an origin sensor 48. The feed arrow 44 is guided by a guide (not shown) so as to be freely movable in the Z1-axis direction. A finger chuck 441 that grips the rear end of the bar W is provided at the tip of the feed arrow 44. This finger chuck 441 is rotatably attached to the other parts of the feed arrow 44, so that it is rotatable about the spindle center line CL as the rotation center axis. The finger chuck 441 grips the rear end of the bar W, so that the feed arrow 44 is connected to the bar W. In other words, while the finger chuck 441 is gripping the bar W, the feed arrow 44 moves in the Z1-axis direction together with the bar.

The feed arrow drive mechanism 45 is composed of pulleys (not shown) provided at the front and rear ends of the material feeder 4, and a drive belt stretched around the pulleys. A connecting portion 451 is fixed to the drive belt. This connecting portion 451 connects the drive belt to the rear end of the feed arrow 44. The pulley provided at the rear end of the material feeder 4 is fixed to the output shaft of the feed arrow motor 46.

When the output shaft of the feed arrow motor 46 rotates in one direction, the feed arrow 44 moves along the Z1 axis toward the NC lathe 2 by the feed arrow drive mechanism 45 and the connecting part 451. Conversely, when the output shaft of the feed arrow motor 46 rotates in the other direction, the feed arrow 44 moves along the Z1 axis away from the NC lathe 2 by the feed arrow drive mechanism 45 and the connecting part 451. Of the multiple bars W stored in the material feeder 4, the bar W whose axis is aligned with the spindle center line CL is gripped by the finger chuck 441. Then, as the feed arrow 44 moves, the bar W gripped by the finger chuck 441 moves in the axial direction of the bar W. That is, when the output shaft of the feed arrow motor 46 rotates in one direction, the bar W moves to its tip side, and when the output shaft of the feed arrow motor 46 rotates in the other direction, the bar W moves to its rear end side. The feed arrow motor 46 has a feed arrow encoder 461. The arrow encoder 461 may be installed separately from the arrow motor 46. The arrow encoder 461 detects the number of rotations and the amount of rotation of the arrow motor 46. The detection result of the arrow encoder 461 is transmitted to the second control device 40 (see FIG. 3).

The tip sensor 47 detects the tip of the bar W. The origin sensor 48 detects whether the feed arrow 44 is located at the feed arrow origin. The feed arrow origin is located at the rear end of the movement range of the feed arrow 44. The origin sensor 48 is a sensor that detects the rear end of the feed arrow 44 at the feed arrow origin. The detection results of these tip sensor 47 and origin sensor 48 are sent to the second control device 40 (see Figure 3). The second control device 40 determines the position of the tip of the bar W when the bar W is first supplied after power is turned on to the NC lathe 2 or when the bar W is newly supplied, based on the detection results of the tip sensor 47 and the feed arrow encoder 461. The second control device 40 also determines the position of the feed arrow 44 based on the detection results of the origin sensor 48 and the feed arrow encoder 461.

FIG. 3 is a block diagram showing the hardware configuration of the lathe system shown in FIG. 1. Note that in FIG. 3, the hardware configuration of the lathe system 1 that is less relevant to the present invention is omitted from the illustration, even if it operates the components described so far.

As shown in FIG. 3, the NC lathe 2 has a first control device 20, the lathe operation panel 24 described above, a Z1-axis motor 252, a spindle motor 253, a spindle actuator 254, and a Z2-axis motor 281. The first control device 20 is a so-called NC (Numerical Control) device, and has a CPU 201, a PLC (Programmable Logic Controller) 202, and a memory unit 203. The first control device 20 is a computer having a calculation function by the CPU 201. The first control device 20 controls the operation of each component such as the spindle 25, the first tool rest 27, the back spindle 28, and the second tool rest 29 shown in FIG. 2 according to the machining program stored in the memory unit 203 and input from the lathe operation panel 24. Some of the motors and actuators that drive each component are shown in FIG. 3. The first control device 20 mainly performs numerical control of the servo motors provided in the NC lathe 2. In addition, the PLC 202 provided in the first control device 20 mainly performs sequence control of the operation of devices other than the servo motors, such as cylinders and valves, provided in the NC lathe 2.

The memory unit 203 stores various programs such as ladder programs and macro programs in advance. In addition to the machining programs, the operator stores various information in the memory unit 203, such as data on tools, diameter data of the bar W, and product length data. The memory unit 203 is composed of non-volatile memory such as ROM, HDD, and SSD, and volatile memory such as RAM.

The Z1-axis motor 252 is a servo motor that rotates upon receiving a command from the first control device 20. When the Z1-axis motor 252 rotates, the spindle 25 (see FIG. 2) moves in the Z1-axis direction. An amplifier (not shown) is provided between the first control device 20 and the Z1-axis motor 252, and the Z1-axis motor 252 is controlled by the first control device 20 sending a command to the amplifier. A description of the amplifier will be omitted below. The Z1-axis motor 252 has a Z1-axis encoder 2521. The output of the Z1-axis encoder 2521 is fed back to the first control device 20, so that the first control device 20 constantly knows the position of the spindle 25 (see FIG. 2) in the Z1-axis direction.

The spindle 25 (see FIG. 2) is provided with a spindle motor 253 such as a built-in motor. The spindle motor 253 rotates upon receiving a command from the first control device 20. When the spindle motor 253 rotates, the spindle 25 and the bar material W (see FIG. 2) held by the spindle 25 rotate around the spindle center line CL (see FIG. 2). Note that, like the spindle 25, the back spindle 28 is also provided with a back spindle motor, but the description is omitted. The spindle actuator 254 is an actuator such as a hydraulic cylinder for operating the collet chuck 251 (see FIG. 2). When the spindle actuator 254 moves a chuck sleeve (not shown) in the forward direction, the collet chuck 251 closes and the bar material W is held by the spindle 25. When the chuck sleeve moves in the backward direction, the collet chuck 251 opens and the grip of the bar material W by the spindle 25 is released.

The Z2-axis motor 281 is a servo motor that rotates in response to a command from the first control device 20. When the Z2-axis motor 281 rotates, the back spindle 28 (see FIG. 2) moves in the Z2-axis direction. Note that an X2-axis motor, which is a servo motor that moves the back spindle 28 in the X2-axis direction, is also provided, but its description is omitted. The Z2-axis motor 281 has a Z2-axis encoder 2811. The output of the Z2-axis encoder 2811 is fed back to the first control device 20, so that the first control device 20 constantly knows the position of the back spindle 28 in the Z2-axis direction.

The material feeder 4 has the second control device 40 in addition to the above-mentioned material feeder operation panel 42, the feeder motor 46, the tip sensor 47, and the origin sensor 48. The second control device 40 is a control device that performs sequence control for each component of the material feeder 4. The second control device 40 controls the operation of the feeder motor 46 and an actuator (not shown) provided in the material feeder 4 based on information received from each sensor, the feeder encoder 461, etc. The second control device 40 also controls the operation of the material feeder 4 in response to an operation request from the first control device 20. The second control device 40 is provided with a material feed memory unit 401. The material feed memory unit 401 stores information on the material shortage position indicating that the bar material W needs to be replaced when the feeder 44 advances to that position. The material feed memory unit 401 stores the position at which the collet chuck 251 (see FIG. 2) and the feeder 44 do not interfere with each other when the main shaft 25 is at the most retreated end of the movable range as the initial value of the material shortage position. However, the location of the missing material can be rewritten by input operations from the material feeder operation panel 42 or by the processing program.

The feed arrow motor 46 is a servo motor that rotates upon receiving a command from the second control device 40. The feed arrow 44 (see FIG. 2) moves in the Z1-axis direction as the feed arrow motor 46 rotates. As described above, the second control device 40 constantly grasps the position of the feed arrow 44 in the Z1-axis direction by grasping the movement distance of the feed arrow 44 from the feed arrow origin based on the detection result of the origin sensor 48 and the detection result of the feed arrow encoder 461. The second control device 40 then transmits the position information of the feed arrow 44 to the first control device 20 as one piece of information related to the material feeder 4. The second control device 40 also transmits to the first control device 20 the position in the Z1-axis direction of the tip of the newly supplied bar material W and the tip of the bar material W that was first sent to the NC lathe 2 after the power was turned on. After the NC lathe 2 starts processing, the second control device 40 controls the feed arrow motor 46 to rotate in one direction with a basically constant torque until the remaining material starts to be pulled out. As a result, the bar W is urged by the feed arrow 44 toward the tip of the bar W with a set load. This load is set to a relatively weak load that does not cause any risk of slippage between the bar W and the main shaft 25 when the main shaft 25 is gripping the bar W.

The material feeder operation panel 42 is a touch panel that combines an operation section and a display screen. In addition to the material feeder operation panel 42, the material feeder 4 is provided with an emergency stop button and a torque setting switch for the feed arrow motor 46. The operator of the lathe system 1 can use the material feeder operation panel 42 to manually move the feed arrow 44 (see Figure 2) in the Z1-axis direction and input various setting values for the material feeder 4. The material feeder operation panel 42 also displays various information related to the material feeder 4, such as the various setting values and error contents of the material feeder 4, as well as the operation buttons for the material feeder 4.

The first control device 20 and the second control device 40 are connected by a signal cable. The first control device 20 transmits operation requests and the like to the second control device 40 via the signal cable. The second control device 40 also transmits various information related to the material feeder 4, including the position information of the feed arrow 44, to the first control device 20 via the signal cable at any time. The second control device 40 also transmits a material shortage signal to the first control device 20 when the feed arrow 44 passes the material shortage position. Furthermore, the second control device 40 transmits requested information, such as information on the material shortage position, to the first control device 20 in response to an information transmission request from the first control device 20.

FIG. 4 is a functional block diagram showing the functional configuration of the lathe system shown in FIG. 1. Note that FIG. 4 also shows only the functional configuration that is particularly relevant to the present invention, and the other functional configurations possessed by the lathe system 1 are not shown or described.

As shown in FIG. 4, the first control device 20 comprises a gripping position determination unit 20a, a material length calculation unit 20b, a continuous machining feasibility determination unit 20c, a machining restriction unit 20d, a safety position change unit 20e, a re-gripping feasibility determination unit 20f, and a machine control unit 20g. The machine control unit 20g is a functional configuration achieved mainly by the CPU 201, the memory unit 203, and the PLC 202. The units other than the machine control unit 20g are functional configurations achieved mainly by the CPU 201 and the memory unit 203 shown in FIG. 3. In addition, the second control device 40 comprises a material supply control unit 40a and a feed arrow position grasping unit 40b.

The gripping position determination unit 20a determines the gripping position where the spindle 25 (see FIG. 2) grips the bar W (see FIG. 2) for each gripping. The material length calculation unit 20b calculates the processed material length, which is the length of the bar W required to process one product. The continuous processing feasibility determination unit 20c compares the movement distance from the position of the spindle 25 to the forward end of the movable range of the spindle 25 at the time of judgment with the processed material length, and determines whether the spindle 25 can process the next product while maintaining its grip on the bar W for each product. The processing restriction unit 20d monitors the position of the back spindle 28 and restricts the processing of the bar W gripped by the spindle 25 until the back spindle 28 retreats to a safe position that does not interfere with processing using the spindle 25. The safety position change unit 20e changes the safety position used by the processing restriction unit 20d for judgment. This safe position may be a position described in the machining program, a position input by the operator using the lathe operation panel 24, or a position automatically calculated using interference check software. The re-gripping possibility determination unit 20f determines whether or not re-gripping is possible based on whether or not the position of the feed arrow 44 at the time of determination exceeds the material shortage position. The machine control unit 20g controls the operation of each component of the NC lathe 2. The machine control unit 20g may also transmit operation requests and information transmission requests to the second control device 40.

The material supply control unit 40a is a functional configuration that controls the operation of the feed arrow motor 46 and the like in accordance with the outputs from various sensors provided in the material supply machine 4, the input from the material supply machine operation panel 42, and the operation request from the first control device 20. The material supply control unit 40a performs control to pull out and discharge the remaining material, which is the shortened bar material W, from the NC lathe 2 and supply new bar material W to the NC lathe 2, and control to apply a load in the forward direction to the feed arrow 44 (see FIG. 2) to urge the bar material W toward the tip side. The feed arrow position grasping unit 40b grasps the position of the feed arrow 44 relative to the feed arrow origin by calculating the forward distance of the feed arrow 44 from the feed arrow origin using the detection result of the origin sensor 48 and the detection result of the feed arrow encoder 461. Since the origin sensor 48 detects the rear end of the feed arrow 44, the position of the feed arrow 44 grasped by the feed arrow position grasping unit 40b is equal to the distance in the Z1 axis direction from the feed arrow origin to the rear end of the feed arrow 44. However, the feed arrow position grasping unit 40b can calculate the distance from the feed arrow origin to the tip of the feed arrow 44 by acquiring information on the length of the feed arrow 44 stored in the material supply memory unit 401 and adding that length to the forward distance of the feed arrow 44.

FIG. 5 is a flowchart showing the operation of the lathe system shown in FIG. 1.

The flowchart in Figure 5 shows the operation of the lathe system 1 after the initial operation after power-on is complete, or after the setup work for machining a new product is complete. In the initial operation or setup work, the tip of the bar W is cut off by the cut-off tool. When the initial operation or setup work is complete, the cut-off tool acts as a stopper and the tip of the bar W is in contact with the cut-off tool. In this state, the bar W is pressed against the cut-off tool by being urged toward the tip by the feed arrow 44.

As shown in FIG. 5, the machine control unit 20g first determines whether the multiple-piece mode or the single-piece mode has been selected (step S10). Usually, the multiple-piece mode is selected, but the operator can switch to the single-piece mode if necessary. Switching between the multiple-piece mode and the single-piece mode is performed by operation input from the lathe operation panel 24 or by commands written in the machining program. In the multiple-piece mode, the spindle 25 is retracted to a position where two or more products can be machined without re-gripping, and a re-gripping operation is performed to grip the bar W. However, since the position to which the spindle 25 can be retracted is limited by the position of the feed arrow 44, even in the multiple-piece mode, the spindle may be retracted to a position where only one product can be machined during re-gripping.

If the multiple piece mode is selected (YES in step S10), the material length calculation unit 20b checks whether product length data, which is data on the length of the product obtained as a result of processing, is stored in the memory unit 203 (step S11). Product length data is often stored in the memory unit 203 by the operator together with the processing program, but there are cases where it is not stored in the memory unit 203. If there is product length data in the memory unit 203 (YES in step S11), the material length calculation unit 20b calculates data on the processed material length L3, which is the length of the bar W required to process one product, from the product length data and the tool width data of the cut-off tool stored in the memory unit 203 (step S12). In this step S12, the material length calculation unit 20b calculates the processed material length L3 by adding the tool width to the product length and stores it in the memory unit 203.

On the other hand, if there is no product length data in the memory unit 203 (NO in step S11), the workpiece length calculation unit 20b calculates the processed workpiece length L3 data based on the machining program (step S13). Specifically, the workpiece length calculation unit 20b calculates the advance distance of the spindle 25 in one cycle of the machining program, and stores the advance distance in the memory unit 203 as the processed workpiece length L3. This advance distance corresponds to an example of the axial movement distance of the spindle in the machining program. If the spindle 25 retreats during the machining operation, the actual advance distance obtained by subtracting the total retreat distance from the total advance distance is set as the processed workpiece length L3. In addition, since this calculation targets the movement of the spindle 25 during the machining operation, the movement of the spindle 25 during the gripping is not targeted. In this way, even if there is no product length data in the memory unit 203, the processed workpiece length L3 is calculated based on the machining program, which eliminates the need for the operator to input the product length data, thereby improving the operability of the lathe system 1. In addition, even if the operator forgets to input the product length data, the processed workpiece length L3 can be calculated. If there is no product length data in the memory unit 203, the material length calculation unit 20b can also calculate the product length data by subtracting the tool width from the processed material length L3 obtained in step S13 and store the data in the memory unit 203.

Next, the continuous machining feasibility determination unit 20c compares the spindle distance Zc (an example is shown in FIG. 7), which is the movement distance from the position of the spindle 25 at that time to the forward end of the movable range of the spindle 25, with the workpiece length L3 (step S14). Hereinafter, the forward end of the movable range of the spindle 25 may be referred to as the Z1-axis forward end. If the spindle distance Zc is equal to or greater than the workpiece length L3 (NO in step S14), the continuous machining feasibility determination unit 20c determines that the next product can be processed without re-gripping while the spindle 25 maintains its grip on the bar material W, and proceeds to step S19. On the other hand, if the spindle distance Zc is less than the workpiece length L3 (YES in step S14), the continuous machining feasibility determination unit 20c determines that re-gripping is necessary. This step S14 corresponds to an example of a continuous machining feasibility determination process. Furthermore, the operations from step S14 onwards are repeated to process the required number of products, resulting in a cyclic operation in which one product is manufactured in one cycle.

If it is determined that a re-grabbing is necessary (YES in step S14), the re-grabbing possibility determination unit 20f determines whether or not a re-grabbing is possible (step S15). Here, the re-grabbing possibility determination unit 20f determines whether or not a re-grabbing is possible based on whether or not the feed arrow 44 has passed the material shortage position. When the first control device 20 receives a material shortage signal transmitted from the second control device 40 when the first control device 20 has passed the material shortage position, the first control device 20 stores information indicating a material shortage in the memory unit 203. In addition, when a new bar material W is supplied, the first control device 20 erases information indicating a material shortage from the memory unit 203. The re-grabbing possibility determination unit 20f determines that a re-grabbing is impossible if information indicating a material shortage exists in the memory unit 203. On the other hand, the re-grabbing possibility determination unit 20f determines that a re-grabbing is possible if information indicating a material shortage does not exist in the memory unit 203. If the gripping possibility determination unit 20f determines that gripping is not possible (NO in step S15), the machine control unit 20g transmits an operation request to the second control device 40 to have the spindle 25 release the grip of the bar W, then discharge the remaining bar W, which is the shortened bar W, and supply a new bar W (step S16). When the new bar W is supplied, the machine control unit 20g executes a bar supply operation in which the spindle 25 grips the supplied bar W, moves the spindle 25 forward until the tip of the bar W protrudes slightly from the guide bush 26, and cuts off the tip of the bar W.

If the gripping possibility determination unit 20f determines that gripping is possible (YES in step S15) or when the supply of new bar material W (step S16) is completed, the process proceeds to step S17, where the gripping position determination unit 20a calculates the gripping position and determines the gripping position where the spindle 25 grips the bar material W during gripping (step S17). This step S17 and steps S171 to S177 shown in Figure 6, which shows the detailed operation thereof, correspond to an example of a gripping position determination process.

FIG. 6 is a flow chart showing the gripping position determination operation shown in FIG. 5. Also, FIG. 7 is a plan view for explaining the positional relationship in the gripping position determination operation shown in FIG. 6.

As shown in FIG. 6, in the gripping position determination operation, the gripping position determination unit 20a acquires the spindle movable distance Zst, the set movable distance Zp, the processed material length L3 calculated by the material length calculation unit 20b, and the material shortage distance L12 from the memory unit 203 (step S171).

Here, the distance and length acquired in step S171 will be explained with reference to FIG. 7. The distance and length explained with reference to FIG. 7 are the distance and length in the Z1-axis direction. The spindle movable distance Zst is the maximum distance that the spindle 25 can move in the Z1-axis direction and is also called the spindle stroke. In FIG. 7, the collet chuck 251 when the spindle 25 is at the most forward Z1-axis forward end is shown with a two-dot chain line, and the spindle 25 when it is at the most backward retracted end is shown with a solid line. The distance between these is the spindle movable distance Zst. This spindle movable distance Zst is stored in the memory unit 203 when the NC lathe 2 is manufactured. In FIG. 7, an example of the position of the collet chuck 251 while the spindle 25 is continuously machining multiple products without re-gripping is also shown with a dashed line. The set movable distance Zp is the distance that the spindle can move set by the operator, and is the distance that the spindle 25 can retract from the Z1-axis forward end. The set movable distance Zp may not be set. In this case, the spindle movable distance Zst is used as the set movable distance Zp in the calculation described below. The set movable distance Zp or the spindle movable distance Zst used here corresponds to an example of the movable distance of the spindle 25 in the Z1-axis direction. The missing material distance L12 is the advance distance of the feed arrow 44 from the feed arrow origin to the missing material position. Information on the missing material distance L12 is stored in the material supply memory unit 401, but is also sent from the second control device 40 to the first control device 20 when the lathe system 1 is started up, and is stored in the memory unit 203.

Then, the gripping position determination unit 20a calculates the effective remaining material length L11 by subtracting the feed arrow advance distance L10, which is the position of the feed arrow 44 relative to the feed arrow origin, from the missing material distance L12. Information on the feed arrow advance distance L10 is constantly sent from the second control device 40 to the first control device 20, and the gripping position determination unit 20a uses the latest feed arrow advance distance L10 at that time for its calculation. The gripping position determination unit 20a also calculates the possible retreat distance Zm by adding the processed material length L3 to the effective remaining material length L11 (step S172). An example of the possible retreat distance Zm is shown in Figure 7.

Then, the grip position determination unit 20a compares the retreatable distance Zm with the set movable distance Zp (step S173). As described above, when the set movable distance Zp is not set, the comparison and calculation are performed using the spindle movable distance Zst instead of the set movable distance Zp, but in the following explanation, the case where the spindle movable distance Zst is used will also be explained as the set movable distance Zp. If the retreatable distance Zm is equal to or greater than the set movable distance Zp (YES in step S173), the grip position determination unit 20a determines that the spindle 25 can move to the retreat end of the set movable distance Zp, and sets the set movable distance Zp to the maximum retreat distance Zr (step S174). On the other hand, if the retreatable distance Zm is less than the set movable distance Zp (NO in step S173), the grip position determination unit 20a determines that the spindle 25 cannot move to the retreat end of the set movable distance Zp, and sets the retreatable distance Zm to the maximum retreat distance Zr (step S175).

Then, the gripping position determination unit 20a obtains the quotient N obtained by dividing the maximum retreat distance Zr by the workpiece length L3 and the remainder α (step S176). This quotient N corresponds to the number of products that the spindle 25 can process while maintaining its grip on the bar W after performing a re-gripping operation in which the spindle 25 moves to the position determined by this gripping position determination operation. Next, the gripping position determination unit 20a determines the position where the spindle 25 retreats from the forward end of the Z1 axis by the distance obtained by multiplying the quotient N obtained in step S176 by the workpiece length L3 as the gripping position to be used during the re-gripping operation (step S177). This completes the gripping position determination operation.

However, the bar W is in a cantilevered state at the rear end side of the gripping portion where the collet chuck 251 of the spindle 25 grips the bar W, and depending on the length of the rear end side of the bar W and the rotation speed of the spindle 25, the bar W may rotate with a large swing. If the rear end side of the bar W rotates with a large swing, the spindle 25 gripping the bar W vibrates, which reduces the processing quality and may result in a defective product. The swing of the bar W becomes extremely large when the bar W rotates at a dangerous speed (a rotation speed at which resonance occurs). The dangerous speed is determined by the properties of the bar W, such as the material and length. In order to avoid rotating the bar W at a dangerous speed, the gripping position of the spindle 25 may be determined to be a position that avoids the dangerous speed. For example, the operator designates the relative position of the feed arrow 44, which will rotate at a dangerous speed, and the spindle 25 as a dangerous range. In the multiple-piece mode, the above-mentioned gripping position determination operation determines that the spindle is to be moved to a position where four products can be manufactured in succession, but if moving to that position places the spindle 25 in a dangerous range specified by the operator, the gripping position may be determined to a position where three products can be manufactured in order to avoid the dangerous speed. The range in which the spindle rotates at a dangerous speed can be specified by the operator based on experience or calculation, but it may also be calculated automatically by the first control device based on the properties of the bar W, such as the material, and the number of rotations of the spindle 25.

As shown in FIG. 5, once the gripping position determination unit 20a has determined the gripping position (step S17), the machine control unit 20g causes the spindle 25 to release its grip on the bar W, moves the spindle 25 to the gripping position determined in step S17, and then causes the spindle 25 to grip the bar W again (step S18). This series of operations in step S18 is the re-gripping of the bar W, and corresponds to an example of a re-gripping process.

If the spindle distance Zc is equal to or greater than the workpiece length L3 (NO in step S14) or if the back spindle 28 has not retreated to the safe position stored in the memory unit 203 after the gripping change in step S18 is completed, the machining restriction unit 20d restricts machining of the bar W held by the spindle 25 (step S19). This step S19 corresponds to an example of a machining restriction process. In step S19, the machining restriction unit 20d restricts the movement of the spindle 25 and the first tool rest 27 by restricting the start of machining of the next cycle on the bar W held by the spindle 25. However, the machining restriction unit 20d may restrict the movement of the spindle 25 and the first tool rest 27 itself. The machining restriction unit 20d does not restrict the rotation of the spindle 25 about the spindle center line CL. This reduces the time it takes to increase the rotation speed of the spindle 25 to the rotation speed required for processing, shortening the time until processing begins after the back spindle 28 has retreated to a safe position.

The safety positions stored in the memory unit 203 are configured to be changeable by the operator. When the operator inputs safety position information from the lathe operation panel 24, the safety position change unit 20e changes the safety position by storing the input safety position in the memory unit 203. Furthermore, if a safety position is specified in the machining program, the safety position change unit 20e reads the safety position from the machining program and stores it in the memory unit 203, thereby changing the safety position. Furthermore, the interference check software and the safety position change unit 20e may be linked to store the safety position automatically calculated by the interference check software in the memory unit 203.

When the back spindle 28 is retracted to a safe position (YES in step S19), the machine control unit 20g starts processing the tip portion of the bar W held by the spindle 25 according to the processing program stored in the memory unit 203 (step S21). After that, when the machined portion machined into the desired shape is cut off by the cut-off tool, the machine control unit 20g determines that one cycle of processing is completed (YES in step S22). The machine control unit 20g counts the number of cycles that have been executed. The number of cycles corresponds to the number of times the machined portion is cut off and also corresponds to the number of products manufactured. The machine control unit 20g stores the number of cycles since the start of the first product processing in the memory unit 203. In other words, the machine control unit 20g counts up the number of cycles in the memory unit 203 when one cycle of processing is completed. Then, the machine control unit 20g determines whether the number of cycles specified in the processing program has been completed since the start of the first product processing (step S23). If the specified number of cycles has been completed (YES in step S23), the cycle operation ends. If the specified number of cycles has not been completed (NO in step S23), the process returns to step S14 and the next cycle operation begins.

FIG. 8 is a flowchart showing the operation of the lathe system shown in FIG. 1 in single-piece mode.

In step S10, if the multiple-piece mode is not selected (NO in step S10), the single-piece mode is selected. The single-piece mode is a mode in which a gripping change is performed for each cycle. In the single-piece mode, performing steps S31 to S36 once is equivalent to performing one cycle. As shown in FIG. 8, in the single-piece mode, the machine control unit 20g moves the spindle 25, which has released the grip of the bar W, to a designated gripping position designated in the machining program, and then causes the spindle 25 to perform a gripping change to grip the bar W (step S31). Note that the designated gripping position used in the single-piece mode may be a position designated by an input operation from the lathe operation panel 24. Next, the machine control unit 20g starts machining the tip portion of the bar W gripped by the spindle 25 according to the machining program stored in the memory unit 203 (step S32). After that, when one cycle of processing is completed by cutting off the machined part machined into the desired shape by the cut-off tool (YES in step S33), the gripping possibility determination unit 20f determines whether gripping is possible or not in the same manner as in step S18 (step S34). If the gripping possibility determination unit 20f determines that gripping is not possible (NO in step S34), the machine control unit 20g transmits an operation request to the second control device 40 to have the spindle 25 release the grip of the bar material W, and then discharge the remaining material, which is the shortened bar material W, and supply a new bar material W (step S35). When the new bar material W is supplied, the machine control unit 20g executes a bar material supply operation in which the spindle 25 grips the supplied bar material W, moves the spindle 25 forward until the tip of the bar material W protrudes slightly from the guide bush 26, and cuts off the tip of the bar material W. If re-gripping is possible (YES in step S34) or if a new bar W is supplied in step S35, the machine control unit 20g determines whether the number of cycles specified in the processing program has been completed since the start of the initial product processing (step S36). If the specified number of cycles has been completed (YES in step S36), the cycle operation ends. If the specified number of cycles has not been completed (NO in step S36), the process returns to step S31 and the next cycle operation begins.

According to the lathe system 1 and the control method for the lathe system 1 of the present embodiment described above, in the multiple piece mode, the spindle 25 executes multiple cycles while maintaining its grip on the bar W, thereby shortening the time required for non-machining compared to the case where gripping is performed every cycle, and improving the productivity of the lathe system 1. In other words, it is possible to reduce the time required for stopping the rotation of the spindle 25 or reducing the rotation speed of the spindle 25 required for gripping, the time required to increase the rotation speed of the spindle 25 to a rotation speed suitable for machining, and the time required for the spindle 25 to grip and release the grip of the bar. In addition, it is possible to reduce the power required for increasing and decreasing the rotation speed of the spindle 25. Furthermore, since the spindle 25 moves relatively evenly throughout the entire range of its movable range, it is possible to suppress the occurrence of load and wear only on a part of the guide structure of the spindle 25 and the movement mechanism of the spindle 25, which also extends the life of these structures and mechanisms.

In addition, the gripping position determination unit 20a determines the gripping position of the spindle 25 at each gripping. As a result, even if the bar material W is moved by an operator manually moving the feed arrow 44, for example, during a cycle operation, after the supply of the bar material W from the material feeder 4 to the NC lathe 2 is completed, the spindle 25 will not grip the feed arrow 44 during gripping, causing an accident in which the feed arrow 44 is broken or the spindle 25 is damaged.

Furthermore, the continuous machining feasibility determination unit 20c determines whether the spindle 25 is positioned at a position where the next product can be processed while the spindle 25 continues to grip the bar material W for each product. As a result, even if the operator manually moves the feed arrow 44 and the bar material W while the spindle 25 is processing multiple products while maintaining its grip on the bar material W, it is possible to prevent accidents caused by the position of the feed arrow 44 and the bar material W being shifted, or problems such as the production of a product with a defective length. Furthermore, in this embodiment, even if the operator manually moves the feed arrow 44 and the bar material W, if the continuous machining feasibility determination unit 20c determines that the spindle 25 is in a position where it can advance beyond the processed material length L3, the processing continues without re-gripping or alarm stop. As a result, the number of re-grippings and stop time can be further reduced, the time required for non-machining by the lathe system 1 can be shortened, and a decrease in the operating rate can be suppressed, so that the productivity of the lathe system 1 is greatly improved.

The machining restriction unit 20d also restricts machining of the bar W held by the spindle 25 until the rear spindle 28 is retracted to a safe position. This safe position can be changed by the safety position change unit 20e, so by setting the safety position to an appropriate position, it is possible to minimize the time during which machining is restricted, particularly when machining multiple products while the spindle 25 is holding the bar W. This also increases the productivity of the lathe system 1.

Furthermore, the convenience of the lathe system 1 is increased because the operator can select between the multiple-piece mode and the single-piece mode depending on the situation.

Next, a modified lathe system 1 will be described. In the following description, components, controls, and operations that have the same names as components described so far will be assigned the same reference numerals as used so far, and duplicate descriptions may be omitted.

The lathe system 1 of this modified example differs from the previous embodiment in that the first control device 20 (see FIG. 3) calculates the missing material distance L12. The first control device 20 calculates the missing material distance L12 immediately after calculating the workpiece length L3 in step S12 or step S13 shown in FIG. 5. The first control device 20 acquires the spindle movement distance Zst of the spindle 25, the length L6 of the collet chuck 251 in the Z1 axis direction, the distance L7 from the tip of the collet chuck 251 to the rear end of the NC lathe 2 when the spindle 25 is located at the rear end of the spindle movement distance Zst, the distance L8 between the NC lathe 2 and the material feeder 4, and the distance L9 from the tip of the feed arrow 44 to the front end of the material feeder when the feed arrow 44 is located at the feed arrow origin. All of these distances and lengths are stored in the memory unit 203 (see FIG. 3). In FIG. 7, the feed arrow 44 located at the feed arrow origin is shown by a dashed line. The first control device 20 calculates the material shortage distance L12 = L7 + L8 + L9 + Zst - L3 - L6. Then, in step S15 shown in FIG. 5, the gripping possibility determination unit 20f determines whether or not gripping is possible based on whether or not the feed arrow 44 has advanced beyond the material shortage distance L12 calculated from the feed arrow origin. Furthermore, the gripping position determination unit 20a performs calculations using the material shortage distance L12 calculated in step S172 without acquiring the material shortage distance L12 in step S171 shown in FIG. 6.

This modified lathe system 1 also provides the same effects as the previous embodiment.

Next, we will explain the second embodiment of the lathe system 1.

FIG. 9 is a functional block diagram similar to FIG. 4, showing the functional configuration of the lathe system of the second embodiment.

As shown in FIG. 9, the lathe system 1 of the second embodiment differs from the previous embodiment in that it does not have a continuous machining feasibility determination unit 20c, but instead has a feed arrow position determination unit 20h. The feed arrow position determination unit 20h compares the calculated theoretical position of the feed arrow 44 (see FIG. 2) with the position of the feed arrow 44 received from the second control device 40, and determines whether they match for each machining of a product.

FIG. 10 is a flowchart similar to FIG. 5 showing the operation of the lathe system shown in FIG. 9.

Since the lathe system 1 of the second embodiment does not have a continuous machining feasibility determination unit 20c, there is no step S14, as shown in FIG. 10, unlike the previous embodiment. Instead, just before the start of machining in step S21, the feed arrow position determination unit 20h determines whether the position of the feed arrow 44 at that time coincides with the theoretical position of the feed arrow 44 (step S01). This step S01 corresponds to an example of a feed arrow position determination process. In step S01, the feed arrow position determination unit 20h calculates the theoretical position of the feed arrow 44 at the completion of machining of the previous cycle from the position of the feed arrow 44 at the start of machining of the previous product, i.e., the start of the previous cycle operation, and the length of the processed material L3. In detail, it calculates the position where the feed arrow 44 has moved forward by the length of the processed material L3 from the start of the previous machining. Note that in the first cycle after power-on or after a new bar material W is supplied, this step S01 is omitted. The feed arrow position determination unit 20h determines whether the calculated theoretical position of the feed arrow 44 matches the position of the feed arrow 44 at the time of determination received from the second control device 40. For example, when the lathe system 1 is temporarily stopped or stopped due to a power outage or emergency stop, the operator may manually move the feed arrow 44 and the bar W. In that case, the position of the feed arrow 44 differs from the calculated position.

If the position of the feed arrow 44 matches the theoretical position (YES in step S01), proceed to step S21 and start machining. On the other hand, if the position of the feed arrow 44 differs from the theoretical position (NO in step S01), the feed arrow position determination unit 20h stops the lathe system 1 with an alarm and displays on the lathe display screen 242 that the position of the feed arrow 44 differs from the theoretical position (step S02).

The machine control unit 20g of this second embodiment also stores the number of cycles since the previous gripping in the memory unit 203. That is, when one cycle of processing is completed, the number of cycles since the previous gripping is counted up in the memory unit 203. Each time one cycle of processing is completed (YES in step S22), the machine control unit 20g determines whether N cycles of processing have been completed since the previous gripping (step S03). This N is the quotient N calculated in step S176. If N cycles of processing have been completed (YES in step S03), the machine control unit 20g proceeds to the above-mentioned step S23. If N cycles of processing have not been completed (NO in step S03), the process returns to step S19 and starts the operation of the next cycle.

The lathe system 1 and the control method for the lathe system 1 of the second embodiment described above have the same effects as the previous embodiment. In addition, since the feed arrow position determination unit 20h determines whether the position of the feed arrow 44 matches the theoretical position for each product being machined, it is possible to prevent the production of defective products and collisions of structures even if the operator manually moves the feed arrow 44 and the bar W. However, since the feed arrow position determination unit 20h issues an alarm to stop the lathe system 1 when the position of the bar W shifts, there is a risk that the number of times the workpiece is re-gripped and the downtime will increase compared to the previous embodiment.

The present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the claims. For example, in this embodiment, the gripping position determination unit 20a and the continuous machining feasibility determination unit 20c perform calculations using the workpiece length L3, but in this calculation, instead of the workpiece length L3 itself, the length obtained by adding the margin specified by the operator to the workpiece length L3 may be used. In that case, the workpiece length L3 may be used in part of the calculation, and the length obtained by adding the margin to the workpiece length L3 may be used in the remaining calculation. In particular, in the calculation of the retractable distance Zm in step S172, it is preferable to use the length obtained by adding the margin to the workpiece length L3. By adding the margin, interference between the collet chuck 251 of the spindle 25 and the feed arrow 44 can be reliably prevented during re-gripping when the gripping position is determined with the retractable distance Zm as the maximum retraction distance Zr. In addition, the determination of whether the tip position of the feed arrow 44 coincides with the theoretical position of the feed arrow 44 (step S01) is performed immediately before the start of processing, but it may be performed at other times, or may be performed multiple times during one cycle of processing. However, by determining whether the position of the feed arrow 44 is normal at least immediately before the start of machining, it is possible to increase the possibility of preventing the production of defective products and collisions with the structure of the NC lathe 2 or the bar W. Also, if the position of the feed arrow 44 differs from the theoretical position (NO in step S01), instead of stopping with an alarm, the process may proceed to step S15 to perform re-gripping, or the spindle 25 and the feed arrow 44 may be controlled so that the feed arrow 44 moves to the theoretical position, or the lathe system 1 may be restarted.

Note that even if a component is included only in the description of each of the embodiments and variations described above, that component may be applied to other embodiments or other variations.

1 lathe system (machine tool system), 20a gripping position determination unit,
25 spindle, 44 feed shaft, L3 workpiece length, W bar material,
Zp setting movable distance

Claims

A machine tool system for manufacturing a plurality of products from a single bar by repeatedly machining a tip portion of a long bar and cutting off the machined portion, comprising:
a main shaft that, when re-gripping the bar material, releases the grip of the bar material and moves along the axial direction of the bar material to a gripping position to grip the bar material;
A feed arrow moving in the axial direction together with the bar;
and a gripping position determination unit that calculates, for each gripping change, the number of products that can be machined while the spindle maintains its grip on the bar stock based on the position of the feed arrow, the distance the spindle can move in the axial direction, and the length of the workpiece required to process one of the products, and determines the gripping position corresponding to the number of products.
The machine tool system according to claim 1, further comprising a continuous machining feasibility determination unit that determines whether the next product can be machined while the spindle continues to grip the bar material, for each of the products being machined.
The machine tool system according to claim 1, further comprising a feed arrow position determination unit that determines whether the position of the feed arrow coincides with the theoretical position of the feed arrow obtained by calculation for each machining of the product.
The machine tool system according to claim 1, further comprising a workpiece length calculation unit that calculates the workpiece length based on the axial movement distance of the spindle in a machining program that describes machining operations.
The machine tool system according to claim 1, characterized in that it is possible to switch between a multiple-piece mode in which the gripping position determination unit determines the gripping position and performs the gripping, and a single-piece mode in which the gripping is performed each time one of the products is processed.
a back spindle disposed opposite the spindle and to which the machined portion is transferred;
a machining restricting portion that restricts machining of the bar held by the spindle until the back spindle is retracted to a safety position;
6. The machine tool system according to claim 1, further comprising a safety position changing unit for changing the safety position.
A method for controlling a machine tool system for manufacturing a plurality of products from a single bar stock by repeatedly machining a tip portion of the bar stock held by a spindle and cutting off the machined portion, comprising:
a gripping position determination step for calculating the number of products that can be machined while the spindle is still gripping the bar stock, based on the position of a feed arrow that moves in the axial direction of the bar stock together with the bar stock, the axial movement distance of the spindle, and the length of the workpiece required to process one of the products, and determining a gripping position corresponding to the number of products;
a re-gripping process in which the spindle, which has released its grip on the bar material, moves to the gripping position determined in the gripping position determination process and grips the bar material again.