JPS6225203B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a playback type numerically controlled machine tool, and in particular, to a playback type numerical control machine tool that can obtain the optimum feed rate during playback without having to input the feed rate for each individual feed operation during teach-in, and at the same time improves operability during teach-in. The company provides controlled machine tools. Here, teach-in refers to storing machining information through direct operation of the machine, and playback refers to automatic operation based on the memorized machining information. Note that in this specification, numerical control is abbreviated as NC. Therefore, numerically controlled machine tools are called NC machine tools. Conventional teach-in methods for feed operations on playback type NC machine tools include: pressing a button, etc. each time after completing the positioning of the tool or table, and memorizing the position; and 2) automatically resetting the position at fixed time intervals or at fixed travel distances. There were two methods; The former method has disadvantages such as the need to input the feed speed each time, which requires a large number of button operations, which requires time and effort, and if these operations are forgotten, malfunctions may occur during playback. In addition, the latter method avoids the troublesome teach-in operation, but since the feed speed during playback is the same as during teach-in, when it is simply a positioning feed (fixed-dimension feed such as cutting fixed-distance feed) In the case where the positioning method is not used), the high-speed positioning ability of the NC machine tool cannot be fully utilized, resulting in the problem of being uneconomical. In other words, in cases such as precision positioning, low-speed feed is required during teach-in, but even though playback operation after teach-in requires higher speed to improve efficiency, it is not possible to meet such requirements. I couldn't do it. Furthermore, in the conventional teach-in method, there were also problems with the positioning feed operation method during teach-in, and improvements in operability were required. In the machining of workpieces, not only the cutting process but also
A large number of positioning operations are required even in the connecting portions. Regarding the positioning accuracy of the joint part, there are cases as follows. (A) Rough positioning where precision is not particularly required, such as when the tool escapes at the end of cutting or when avoiding obstacles on the movement path. (B) When precise positioning operations are required, such as positioning to the cutting start position. Regarding the feed rate during positioning, there are cases as follows. (C) When high speed is required to travel long distances. (A) When low speed is required near precision positioning points. Positioning feed operation devices include fixed size feed operation devices that automatically feed by keying in the travel distance, non-fixed size feed operation devices that have separate feed speed setting devices and operation devices that start and stop feeding, and ,
There are handle-type feed operation devices that are suitable for precise positioning in a relatively narrow range. However, these devices have practical problems, such as requiring a large number of device operations to start feeding, requiring two-handed operations to start/stop feeding and adjusting speed, and having limited positioning ranges. be. For this reason, conventionally, it has not been possible to widely meet each of the above requirements (A) to (D) with one type of feed operation device. Therefore, when positioning to a certain position, it is often necessary to use a combination of a plurality of feed operation devices, which poses many operational problems. The purpose of the present invention is to eliminate the drawbacks and problems of the prior art, and to provide a playback type NC machine tool that can obtain the optimum feed rate during playback without having to input the feed rate for each individual feed operation during teach-in. It is to provide. As mentioned above, the feed speed during playback is different when the same speed as during teach-in is required, such as cutting fixed-dimension feed, and when low speed is required during teach-in, such as positioning, but high speed is required during playback. may be required. The present invention provides feed operating devices for teach-in independent of each other in response to these cases, and in the case of fixed-length feeding, both positioning information and feed speed information are acquired by signals from the feed operating device. In the case of simple positioning, only the positioning information is taken in and stored as a fast forwarding speed, thereby achieving the above object. That is, the present invention provides a playback type NC in which machining information is taught in by direct operation of the machine, and then playback operation is performed based on the machining information.
In a machine tool, a constant feed operation device outputs constant feed command information including positioning information of a table of the machine tool and its feed rate information, and a rapid feed command having a variable feed rate function and including positioning information of the table. A rapid-feed operation device that outputs information and a constant-feed operation device based on the constant-size feed command information.
NC that creates NC command information and creates NC command information for rapid traverse based on the aforementioned rapid traverse command information
The present invention is characterized by comprising a command creation section, and an NC control device that controls the driving means of the table based on the created NC command information, constant feed command information, and rapid feed command information. Furthermore, both starting and stopping the feed of the feed operation device for performing the rapid feed process and adjusting and instructing the speed are performed by the same manual operation device, and the relationship between the displacement amount of the manual operation device and the feed rate is further provided. If the speed gradient increases as the amount of displacement increases, it becomes possible to start (including direction) and stop the feed and adjust the speed with a single handle or lever, reducing the number of teach-in operations. In addition, due to the ergonomic effect, both precise positioning operations using minute feeds and high-speed feed operations can be performed smoothly. Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a block diagram showing an example of the hardware configuration of the playback type NC machine tool of the present invention. Based on this diagram, the relative arrangement of each device, the flow of signals and information, and the information processing process are explained in detail. Explain. In the following explanation, the table is fed in a uniaxial direction for the sake of simplicity, but it is also possible to feed the table in multiple axial directions, which are substantially the same. In Fig. 1, the playback type NC machine tool includes a machine tool 12, an operation panel 1, and
4, NC control device 16, and control computer 1
It is equipped with 8. Servo motor 20 for feeding the table of machine tool 12
is the feed operation signal from the operation panel 14 and the computer 18
The drive is controlled by the NC control device 16 based on the NC command information N _t from. Further, a number of pulse signals P _p proportional to the number of rotations of the servo motor 20 are output from the NC control device. In the calculator 18, at the time of teach-in,
The feed operation signal from the operation panel 14 and the table position information P _c obtained by integrating the number of P _p with the pulse counter (current position counter) 22 are taken in, and the NC command generation unit TCH generates the NC command information N. create _t ,
A process of storing this in the storage device 24 is performed. On the other hand, during playback, in the computer 18, the NC command sending unit PB sends the data to the storage device 24.
A process of extracting NC command information _Nt from the NC control unit 16 and sending it to the NC control device 16 is performed. The operation panel 14 includes a rapid traverse operation section for performing rapid traverse processing that takes in only positioning information and converts it into NC commands at a rapid traverse speed (creating NC command information), and a positioning section for fixed-dimension feeding for automatic feed cutting, etc. There are three types of feed operation units: a fixed size feed operation unit that takes in both information and feed rate information and converts it into NC commands, and a handle feed operation unit that is used for manual feed cutting or minute distance positioning. An operating section is provided. The fast-forward operation section is provided with a fast-forward lever switch 26, and by tilting the lever, a fast-forward start signal R _s including the feed direction and a fast-forward speed signal F _r corresponding to the inclination angle are sent to the NC control device 16 . The servo motor 20 of the machine tool is driven via the NC control device. When the lever is released, it automatically returns to the neutral position, the output of the fast-forward start signal R _s is stopped, and the servo motor 20 is stopped. The details of this fast forward lever switch 26 will be explained later with reference to FIG. The sizing feed operation section includes a keyboard 28, a sizing feed start button 30 including the feeding direction, a sizing feed stop button 32, a sizing feed speed setting dial 34, a numerical display 36, and a sizing feed control device 38. It is provided. The fixed size feed control device 38 controls the amount of movement from the keyboard 28 and the fixed size feed start button 30.
It sequentially captures the feed directions from and to the machine tool table, sends the sizing feed start signal _Cs and the feed amount information _Lg to the NC control device 16, and uses the servo motor 20 controlled by the NC control device to move the table of the machine tool. Move the specified distance. At this time, the NC control device outputs the fixed size feed rate signal F from the fixed size feed rate setting dial 34.
Adjust the feed rate by taking in _c . Numerical values entered from the keyboard 28 are displayed on a numerical display 36. When the fixed size feed stop button 32 is pressed, the drive of the servo motor 20 can be temporarily stopped by the fixed size feed start signal _Cs through the NC control device 16, and when the fixed size feed start button 30 is pressed again, the servo motor 20 can be stopped. can continue to drive. When the table movement by the distance specified by the keyboard 28 is completed, the NC control device outputs a fixed-size feed completion signal F _e and resets the fixed-size feed control device 38. The rapid feed speed signal F _r and the constant feed speed signal F _c
Either one is selected by the changeover switch 40 operated by the rapid feed start signal R _s and the fixed size feed start signal C _s and is transmitted to the NC control device 16 . A manual feed handle 42 is provided in the handle feed operation section. The manual feed handle transmits a number of pulse signals (handle feed signals) H _p proportional to the rotational position to the NC control device 16, thereby driving the servo motor 20 of the machine tool in a stepwise manner. The operation panel 14 further includes a feed stop detection device 4.
4 are provided. The feed stop detection device monitors the rapid feed start signal R _s and the constant feed start signal C _s , and when detecting their disappearance, outputs the rapid feed stop interrupt signal R _i and the constant feed stop interrupt signal C _i to the computer. Send to 18. In addition, since it is difficult to directly detect the stoppage of the manual feed handle 42 from the handle, in the illustrated embodiment, a pulse signal for displaying the current position is transmitted from the NC control device 16 to the pulse counter (current position counter) 22. A method is adopted in which detection is performed by combining P _p with rapid feed and constant feed start signals R _s and C _s . In other words, a handle feed start/stop detection device is provided, whereby the input of the pulse signal P _p for displaying the current position is manually fed during the period when both the rapid feed start signal R _s and the constant feed start signal C _s are in the OFF state. It is determined that the handle 42 is being moved, and based on this, the stoppage of the feed is detected. Further, the handle feed start/stop detection device transmits a handle feed stop interrupt signal H _i to the computer 18 when the handle feed is interrupted for a certain period of time. The fixed size feed rate signal F _c from the fixed size feed rate setting dial 34 is also transmitted to the computer 18 . Furthermore, in the case of handle feeding using the manual feed handle 42, a feed time measurement start/stop signal T _s is output from the handle feed start/stop detection device 46.
is given to the feed time measuring device 48, and based on this, the time measuring device 48 measures the feed time measurement value T _f and transmits it to the computer 18. During teach-in, the NC command creation unit TCH of the computer 18 receives the current position information P _c from the current position counter 22 , the handle feed stop interrupt signal H _i from the handle feed start/stop detection device 46 , and the feed from the feed time measuring device 48 . Receives the time measurement value T _f , the rapid feed stop interrupt signal R _i and constant feed stop interrupt signal C _i from the feed stop detection device 44, and the constant feed speed signal F _c , and sequentially teaches-in.
NC command information _Nt is created and sent to the storage device 24. At the time of playback, an NC command sending request signal D _e is transmitted from the NC control device 16 to the NC command information sending unit PB of the computer, and based on the sending request signal, NC command information N _t is sequentially retrieved from the storage device 24 and NC Sent to the control device. In FIG. 1, reference number 50 indicates a current position display device that operates in response to the current position display pulse signal P _p , and reference numbers 52 and 54 indicate the NC operation start button and the NC operation start button provided on the operation panel 14. Each shows a stop button. When the NC operation start button 52 is activated, the NC start signal S _t is activated by the NC control device 16.
When the NC operation stop button 54 is activated, an NC stop signal _Sp is sent to the NC control device 16. FIG. 2 is a flowchart showing the processing of the teach-in NC command information creation unit TCH in the embodiment shown in FIG. The NC command information creation unit TCH is equipped with processing modules corresponding to three types of feed operations: rapid feed operation, fixed length feed operation, and handle feed operation. The fast-forwarding processing module is activated by the fast-forwarding stop interrupt signal R _i , takes in the current position information P _c and creates (GOO) type NC command information (feeding command) N _t for fast forwarding. The fixed size feed processing module is activated by the fixed size feed stop interrupt signal C _i and receives current position information P _c
and fixed size feed speed signal F _e are taken in to create (G01) type NC command information N _t for fixed size cutting feed. The handle feed processing module is activated by the handle feed stop interrupt signal H _i , takes in the current position information P _c , and calculates the amount of movement l between the previously captured position information P _c in memory and the current P _c calculate.
At the same time, the feed time measurement value T _f is taken in and the average feed speed f is calculated from this and the movement amount l. In this way, from the current position information P _c and the average feed rate f, the (G01) type NC command information N _t for constant cutting feed is obtained.
Create. Figure 3 shows the fast forward lever switch 2 in Figure 1.
FIG. 6 is a diagram showing the detailed structure of FIG. Ball 66 with lever 64 with knob 62
The spherical seat 7
It is pressed to 6. A groove for guiding the lever is formed in the relief seat 76 in the left-right direction in the drawing (parallel to the plane of the paper), and when the knob 62 is moved left and right,
The lever 62 is adapted to rotate around the center of the ball 66. The inclination angle of the concave portion 70 is set to be greater than the maximum static friction angle with the pin 74, so that the restoring force automatically returns the lever 62 to the neutral position (the position indicated by the solid line in the drawing). A pin 78 protrudes from the left and right sides of the ball 66, passing through the center of the ball and perpendicular to the axis of the lever 62. Therefore, when the lever 62 is tilted left or right, one of the plungers 80, 80 on both sides is pushed down depending on the angle of inclination from the neutral axis.
Since each plunger 80 is in contact with another plunger 84 connected to a linear potentiometer 82, the amount of linear movement of each plunger 80 can be detected as a change in the electrical resistance of the potentiometer 82. Each plunger 84 is provided with a spring 86 and a stopper 88, so that only when the upper plunger 80 is pushed down from the neutral position, the lower plunger 84 moves up and down in conjunction with this. Therefore, when the lever 62 is tilted in one direction, only one of the potentiometers 82 can be operated. A voltage from a constant voltage source E is applied to both ends of the variable resistor R inside each potentiometer 82. Therefore, depending on the inclination angle θ of the lever 62, the voltage V generated between the sliding terminal of one potentiometer 82 and the other terminal changes. The voltage V is converted into digital information by an analog-to-digital converter 90. This embodiment shows the case of converting into a 3-bit digital code, and the inclination angle θ of the lever 62 can be encoded in 8 steps on each side. Adjust so that the sign at the neutral position of the lever 62 is 000, and connect the OR circuit.
By calculating the logical sum of each bit in _G1 , a + direction or one direction fast forward start signal R _s+ or R _s- can be generated and transmitted to the NC control device 16 (FIG. 1). The respective output codes of the analog-to-digital converters 90 and 90 that share two directions are logically summed bit by bit in an OR circuit G ₂ and transmitted to the NC control device 16 as a fast forward speed signal F _r . In this way, by tilting the lever 62 from the neutral position, the feeding direction and speed of the table of the machine tool 12 can be controlled with one-touch operation according to the tilt direction and angle. Note that reference number 92 in FIG. 3 indicates a dustproof rubber cover. Lever inclination angle θ and feed speed (table feed speed) of the rapid feed lever switch 26 in FIGS. 4 and 3
It is a figure which illustrates the relationship with v. In this example, the lever 62 can be tilted to either side within a range of 30 degrees. The feed speed v can be varied in eight steps from 0 to 2400 mm/min with respect to the inclination angle θ. A dead zone of zero speed is provided near θ=0. In the example shown in FIG. 4, an exponential relationship is approximately given between the lever inclination angle θ and the table feed speed v as follows: v=A _p ×r〓 (1). this is,
Focusing on the fact that the movement of a human's (operator's) limbs has linear control characteristics, the sense of speed is nonlinear (Weber's law). ) and the feed speed (v), so that both precise positioning by minute feed during teach-in and high-speed feed can be performed smoothly. In other words, it is based on ergonomic considerations. The setting of the minimum speed v _p of the table feed speed v is
In NC machine tools, the minimum setting unit α (mm) for the feed amount (distance) is set for each machine, and is called the positioning resolution, which is important for performing high-precision positioning operations during teach-in. Therefore, in order to perform positioning with accuracy α, the operating time of the lever 62 required to move and stop the table by distance α must be set so that it is not shorter than the minimum human response time. . Mathematically, it is necessary to have the following relationship. t'=α/v _p ≦t...(2) Here, t': Time required to move by minimum setting unit α: Minimum setting unit (mm) v _p : Minimum feed speed t: Human minimum response time formula ( Solving 2) for v _p yields v _p ≦α/t (3). When setting α=0.01 mm and t=0.4 seconds and finding V _p from equation (3), v _p ≦0.01/0.4=0.025 mm/second=1.5 mm/minute. In reality, taking into account a margin, v _p is set to, for example, 1 mm/min. In this way, precise positioning feed and light rapid feed during teach-in can be freely performed with a single lever operation. Table 1 numerically represents the graph of the setting example shown in Fig. 4, and shows the lever inclination angle (θ
3 shows an example of the digital codes of the +direction fast-forward start signal R _s +, the one-way fast-forward start signal R _s- , the fast-forward speed signal F _r , and the table feed speed v. In the vicinity of θ=0, R _s+ , R _s- , and _Fr are all 0, forming a dead zone.

[Table] FIG. 5 is a diagram showing another embodiment improved so that the inclination angle θ of the lever 64 of the rapid-forward lever switch 26 can be more easily set to the position of the minimum feed speed v _p . In this embodiment, a minute concave surface Q ₁ is formed at the center bottom of the concave surface portion 70 to stabilize the pin 74 at a neutral point. Further, there are minute steps Q 2 and _{Q 3 at} the tip position of the pin 74 when the lever 64 is tilted by the tilt angle θ _p corresponding to the minimum feed speed v _p .
is formed. By forming the contour of the concave surface portion 70 in this way, when the lever 64 is moved, the response changes around the inclination angle θ _p , so the setting of θ _p , that is, the minimum feed rate v _p can be easily and reliably set. can be done. The other structures are substantially the same as those shown in FIG. In addition, the fast forward lever switch 2 shown in FIG.
In No. 6, since the bearing portion of the lever 64 is composed of a ball 66 and a spherical seat 76, it is possible to easily implement a structure in which the lever 64 can rotate even within a plane perpendicular to the plane of the paper. With this structure, if a lever inclination angle encoding mechanism similar to that shown in Fig. 3 is provided also in a plane perpendicular to the plane of the paper, two-dimensional feed operation can be performed with a single lever. This makes it possible to further improve positioning operation operability. Furthermore, if an optical position encoding device that combines a position encoded slit and a photoelectric converter is used as a means for detecting the displacement of the lower plunger 88 corresponding to the inclination of the lever 64, it is possible to use a fast forward speed signal F _r
can be directly created, so the analog-to-digital converters 90, 90 can be omitted. Furthermore, problems such as electrical contact failure of the sliding terminal at the variable resistor R are also eliminated. Furthermore, the present invention can also be used for teach-in of playback type robots. Furthermore, the present invention can also be applied to machine tools other than playback type NC machine tools for the purpose of improving their feed operability. As is clear from the above description, according to the present invention, optimal NC command information can be created for each individual feed operation, so machining time during playback can be minimized. Furthermore, a wide range of positioning operations during teach-in can be performed easily and with high precision.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the hardware configuration of a playback type NC machine tool according to the present invention.
Figure 2 is a flowchart showing the flow of each process of the teach-in NC command information creation unit TCH in Figure 1;
FIG. 3 is an explanatory diagram showing the detailed structure of the fast-forward lever switch 26 of FIG. 1, and FIG. 4 is a chart showing an example of the relationship between the lever inclination angle θ of the fast-forward lever switch 26 of FIG. 3 and the table feed speed v. FIG. 5 is an explanatory diagram showing another embodiment in which a part of the fast-forward lever switch of FIG. 3 is improved. 12...Machine tool (machine), 14...Operation panel, 1
6... NC control device, 18... Control computer, 2
4... Memory device, 26... Rapid feed lever switch, 38... Constant feed control device, 40... Changeover switch, 42... Manual feed handle, TCH...
Teach-in NC command information creation unit, PB...NC command information sending unit, _Nt ...Teach-in NC command information.

Claims (1)

[Claims] 1. A playback type NC machine tool in which machining information is taught in by direct operation of the machine and then playback operation is performed based on the machining information, including positioning information of the table of the machine tool and its feed rate information. a fixed-size feed operation device that outputs fixed-size feed command information; a rapid-feed operation device that has a variable feed rate function and outputs rapid-feed command information including positioning information of the table; For fixed size feed
NC that creates NC command information and creates NC command information for rapid traverse based on the aforementioned rapid traverse command information
A playback NC machine tool comprising: a command creation section; and an NC control device that controls a drive means for the table based on the created NC command information, constant feed command information, and rapid feed command information. . 2. In the machine tool according to claim 1, both starting and stopping the feed operation device and adjusting and instructing the speed of the feed operation device for performing the rapid feed process are performed by the same manual operation device, and the manual A playback type NC machine tool characterized in that the relationship between the displacement position of the operating device and the feed speed is such that the speed gradient increases as the displacement position increases.