WO1994023894A1

WO1994023894A1 - Numerical controller and automatic programming apparatus

Info

Publication number: WO1994023894A1
Application number: PCT/JP1994/000556
Authority: WO
Inventors: Takashi Takegahara; Shigetoshi Takagi; Koji Suzuki
Original assignee: Takashi Takegahara; Shigetoshi Takagi; Koji Suzuki
Priority date: 1993-04-13
Filing date: 1994-04-04
Publication date: 1994-10-27
Also published as: JPH06297296A

Abstract

This invention relates to a numerical controller which changes tool speed on depending on the change in load on a tool due to a change of a machining shape, and an automatic programming apparatus. When a work is machined into a bump in an X - Z plane as shown in Fig. 1(A), the value of a rotating load acting on the tool is greater on the downward slope than on the upward slope as shown in Fig. 1(B) if the tool has a flat edge. In other words, even when the machining condition is the same, the load on the tool varies depending on the shape of the work. Accordingly, a load current of 10A is set as a reference, as shown in Fig. 1(C), and the tool feed speed is decreased to reduce the load if the actual current reaches the upper limit of 11A (110 %), whereas the feed speed is increased if the current reaches the lower limit of 9A (90 %).

Description

Akira _t fine manual numerical control equipment and automatic programming Mi packaging equipment technology content field

The present invention relates to a numerical control device for machining a workpiece by controlling the movement of a tool according to a machining program, and an automatic programming device for automatically creating a machining program based on various conditions. The present invention relates to a numerical control device and an automatic programming device that perform control in accordance with the above conditions. Background technology

Conventionally, in NC machine tools, workpieces are machined according to a preset tool input feed speed. The feed rate of this tool is determined from the machining conditions such as the shape and material of the tool tip, and is controlled to maintain this set feed rate unless the machining conditions change. I have.

However, even under the same processing conditions, the load on the tool varies depending on the processing shape. For example, when machining a work into a mountain shape using a tool with a flat tip, there is a greater percentage of the part without a cutting blade that contacts the work when going down the mountain than when climbing the mountain. The load also increases. If this is ignored and the tool is controlled to move at a constant feed rate in the same way as other parts, there is a risk that the tool will be damaged or the machining shape will be uneven. Disclosure of the invention The present invention has been made in view of such a point, and provides a numerical controller and an automatic programming device that can flexibly cope with a change in load on a tool due to a change in a processing shape. With the goal.

In order to solve the above-mentioned problems, the present invention provides a numerical control device that processes a workpiece by controlling a movement of a tool according to a machining program, wherein a rotational load detecting unit that detects a rotational load of a spindle that rotationally drives the tool. And a feed speed control means for controlling a feed speed of the tool according to the detected rotational load.

Also, in an automatic programming device that automatically creates a machining program necessary for the operation of the numerical controller based on various conditions. Tool condition data Store machining condition data such as material data etc. Means, target set value calculating means for calculating a target set value of the rotational load based on the machining condition data, and a command for controlling the feed rate of the tool so as to maintain the calculated target set value. And a feed speed control command code creating means for creating a feed speed control command code for performing the control.

In the numerical control device according to the present invention, the rotational load of the main shaft for rotationally driving the tool is detected by the rotational load detecting means, and the feed speed of the tool is controlled by the feed speed control means according to the detected rotational load. On the other hand, in the automatic programming device of the present invention, machining condition data such as tool data and workpiece material data are stored in the machining condition data storage means, and the target set value calculating means is used to store the machining condition data based on the machining condition data. To calculate the target set value of the rotational load A feed speed control command code for instructing the control of the tool feed speed to maintain the target set value is created by the feed speed control instruction code creating means. Brief explanation of drawings

FIGS. 1 (A), 1 (B) and 1 (C) are diagrams for explaining the feed speed control, FIG. 1 (A) is a diagram showing the path of the tool, and FIG. 1 (B) is a diagram of the feed speed. Fig. 1 (C) is a diagram showing the trajectory of the rotational load of the spindle before correction, and Fig. 1 (C) is a diagram showing the trajectory of the rotational load of the spindle according to the corrected feed speed.

Figure 2 shows the schematic configuration of the NC machine tool.

Fig. 3 is a block diagram showing the hardware configuration inside the numerical controller.

Fig. 4 is a flowchart showing the control procedure on the processor side for controlling the feed rate.

Figure 5 is a block diagram showing the outline of the functions of the automatic programming device.

Figure 6 is a block diagram C of the hardware of the automatic programming device. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a diagram showing a schematic configuration of the NC machine tool of the present embodiment. The NC machine tool includes a numerical controller 10 and a machine tool unit 20. A Y-axis table 27 is slidably attached to the table 25 of the machine tool section 20. Y-axis table 2 7 Is by the servo motor 2 _2: is controlled to move connexion Y-axis direction. An X-axis table 26 is slidably mounted on the Υ-axis table 27. The movement of the X-axis table 26 in the X-axis direction is controlled by the servomotor 21.

The work 6 is fixed on the X-axis table 26. The work 6 is cut or ground by the tool 7 while its movement is controlled on the X-Υ plane by the X-axis table 26 and the Υ-axis table 27. The tool 7 is attached to a support 28 attached to the base 25 so as to be able to slide, and is controlled to move in the Ζ-axis direction by the first and second supports 23. The rotation of the tool 7 is controlled by a spindle motor 24. The load current of the spindle motor 24 is detected by the numerical controller 10. The position signals of the servomotors 21 to 23 and the spindle motor 24 are detected by a pulse coder (not shown) or the like and fed back to the numerical controller 10.

The rotating load detecting means 1 of the numerical controller 10 constantly monitors the load current of the spindle motor 24, detects the rotating load of the shaft, and sends it to the feed speed calculating means 3 of the feed speed control means 2. The feed speed calculating means 3 calculates the feed speed of the tool 7 by means described later according to the detected rotational load of the shaft. The calculated feed speed is sent to the interpolation means 4. The interpolation means 4 generates an interpolation pulse according to the calculated feed speed and position data, and sends it to the axis control means 5. The axis control means 5 rotationally drives each of the servomotors 21 to 23 according to the interpolation pulse.

Figure 3 is a block diagram showing the configuration of the hardware inside the numerical controller (CNC). Processor 1 1 controls the entire CNC 10 It is the central processor. The processor 11 reads the system program stored in the ROM 12 via the node 19 and executes control of the entire CNC 10 according to the system program. RAM I3 stores temporary calculation data, display data, and the like. DRAM is used for the RAM I3. The CMO S 14 stores a tool correction amount, a pitch error correction amount, a machining program, parameters, and the like. The CMOS 14 is backed up by a battery (not shown) and is in a non-volatile memory even when the power of the CNC 10 is turned off, so those data are retained.

An interface 15 is an interface for an external device. External devices 34 such as a paper tape reader, a paper tape puncher, a paper tape reader's puncher, and a printer are connected to the interface 15. The processing program is read from the paper tape reader, and the processing program edited in CNC 10 can be output to the paper tape puncher.

The graphic control circuit 16 converts digital data such as the current position of each axis, an alarm, a parameter, and image data into an image signal and outputs it. This image signal is sent to the display device 32 of the CRT ZMD unit 31, where it is displayed. The interface 17 receives data from the keyboard 33 in the CRTZMD unit 31 and passes the data to the processor 11.

The interface 18 is connected to the manual pulse generator 35 and receives a pulse from the manual pulse generator 35. The manual pulse generator 35 is mounted on the machine operation panel, and is used to move the machine working part precisely by hand. PMC (Programmable 'Machine' Controller) 36 is built into CNC 10 and controls the machine side with a sequence-program created in ladder format. That is, the M function, S function, and T function commanded by the machining program are converted into signals required for the machine side by a sequence program, and output to the machine side via the I / O unit 37. This output signal drives a magnet or the like on the machine side to operate a hydraulic valve, a pneumatic valve, an electric actuator, and the like. In addition, it receives signals from the limit switch on the machine side and the switch on the machine operation panel, etc., performs necessary processing, and passes it to the processor 11.

The axis control circuits 41 to 43 receive the movement command of each axis from the processor 11 and output the command of each axis to the servo amplifiers 51 to 53. <The servo amplifiers 51 to 53 In response to the moving finger, the servo motors 21 to 23 of each axis are driven. The servomotors 21 to 23 have a built-in pulse coder for position detection, and the position signal is fed back as a pulse train from this pulse coder. -By converting this pulse train to FZV (frequency / speed), a speed signal can be generated. In the figure, the feedback line and the speed feedback of these position signals are omitted. _(The spindle control circuit 61 receives the spindle rotation command and the spindle orientation command, etc. The spindle motor 62 outputs a spindle speed signal to the spindle amplifier 62. The spindle amplifier 62 receives the spindle speed signal and rotates the spindle motor 24 at the specified rotation speed. Position the spindle in place, and position the spindle with gears or belts. Coda 72 is combined. The position coder 72 rotates in synchronization with the spindle motor 24 and outputs a feedback pulse. The feedback pulse is read by the processor 11 via the interface 71. This feedback pulse is used to move another axis synchronously with the spindle motor 24. Also, the value of the load current of the spindle motor 24 is supplied to the interface 71 from the spindle amplifier 62, and the interface 71 passes the value to the processor 11.

Next, an example of specific feed speed control of the numerical controller having the above configuration will be described.

Fig. 1 (A), Fig. 1 (B), and Fig. 1 (C) are diagrams for explaining feed speed control. Fig. 1 (A) is a diagram showing the trajectory of the tool. Fig. 1 shows the trajectory of the rotational load of the spindle before correction, Fig. 1

(C) is a diagram showing the trajectory of the corrected feed speed and the trajectory of the rotational load of the main shaft corresponding thereto. The horizontal axis in each figure is the X-axis component of the moving direction of the tool 7, and the vertical axis is shown in Fig.

(B) is the load current value (I) of Spin Dormo I.C. 24, and Fig. 1 (C) is the load current value (I) of Spin Dormo I.C. 24 and the feed speed control value (F) of Tool 7. .

In this embodiment, a case is considered in which the work 6 is machined into a mountain shape on the XZ plane as shown in FIG. At this time, if the tip of the tool 7 has a flat shape, the value of the rotational load applied to the tool 7 generally becomes larger when the tool 7 goes down than when climbing a mountain. That is, the characteristics of the load current of the spindle motor 24 in this case are as shown in FIG. 1 (B).

In such a case, move tool 7 while keeping the feed rate constant. If this is done, there is a risk that the tool 7 will be damaged and the processed shape will be uneven. Therefore, in this embodiment, the feed speed of the tool 7 is corrected by the following machining program.

N 1 G 0 1 .0 X 1 0 Z 5 S 1 2 0 0

F 5 0 0 P 1 0 Q 1 1 0 R 9 0

N 2 X 2 0 Z 8

N 3 X 3 0 Z 1 0

N n G 0 1.1. 1

In the program number N1, G01.0 is a code for instructing the start of the feed speed correction of the tool 7 according to the rotational load of the spindle motor 24. That is, the control of the tool 7 is started from the position of (X, Z) = (10.5) based on the rotation speed of 1200 and the feed speed of 500. P indicates the target set value of the load current of the spindle motor 24, and the unit is ampere. Q and R indicate the upper and lower limits of the load current, respectively, and both units are percentages (%).

That is, when a command is issued by the code GO 1.0, the processor 11 sets the load current at 10 amps as the target set value, and when the value reaches the upper limit of 11 amps (110%), the tool 7 The feed rate is reduced by lowering the feed rate of the tool 7 and conversely, the feed rate of the tool 7 is controlled to increase when the lower limit is 9 amps (90%). However, in this case, the commanded feed rate F The value of 500 should not be exceeded.

Fig. 1 shows the relationship between the load current and feed rate by such control. It is shown in (C). Here, the line indicating the load current characteristic is denoted by L1, and the line indicating the feed speed characteristic is denoted by L2. As can be seen from the figure, the load applied to the tool 7 increases from the time when it passes the vicinity of the peak (X = 30) of the mountain shape of the work 6, and the load current value starts to increase. When this load current I reaches 11 amps (around X = 40), the feed rate F is reduced by a predetermined amount from the standard 500. As a result, if the load current I falls sufficiently within the lower limit of 9 amps or more, the feed speed F is maintained.

Since the inclination of the work 6 becomes steeper as the X axis moves, the load current I starts to increase again when the feed speed F is kept constant. In this case, perform the same procedure again. Thereafter, by repeating this procedure, the tool 7 is moved and controlled according to the machining program while the load current I is maintained at around the target value of 10 amperes. Then, when the code G O 1.1 is read in the program number N n, the feed speed control according to the load current is released.

FIG. 4 is a flowchart showing a control procedure on the processor 11 side for performing the feed speed control.

[S1] By reading the code G01.0, the feeding speed control of this embodiment is started.

[S2] It is determined whether or not the load current value of the spindle motor 24 has exceeded the upper limit value. If the load current value exceeds the upper limit value, the process proceeds to step S3. If not, the process proceeds to step S4.

[S3] Decrease the feed speed of tool 7 by a specified amount and go to step S2.o

[S4] It is determined whether the load current value of the spindle motor 24 has fallen below the lower limit value, and if it has fallen below the lower limit value, the process proceeds to step S5. Otherwise, go to step S6.

[S5] The feed speed of the tool 7 is increased by a predetermined amount, and the process returns to step S1. However, in this case, control is performed so as not to exceed the commanded feed speed value.

[S6] It is determined whether or not the feed speed end code GO 1.1 has been read, and if it has been read, the flow chart ends. If not, the flow returns to step S1.

As described above, in the present embodiment, the feed rate of the tool 7 is controlled so as to maintain the target set value of the load current specified by the program, so that it is possible to flexibly cope with a change in load due to a processing shape. be able to.

Next, a second embodiment of the present invention will be described.

FIG. 5 is a block diagram schematically showing functions of the automatic programming device of the present embodiment. The machining condition data storage means 101 is provided with a tool data area 101a, a work data area 101b, and an NC machine data area 101c. The tool data area 101 a stores, in addition to the tool number, the tool length correction number, the tool material, and the like, the permissible load factor T, the upper limit rate Q of the load, the lower limit rate R, and the like specific to this embodiment. The workpiece data area 101b stores the material of the workpiece, the feed rate coefficient, the load factor M according to the material, and the like. The NC machine data area 101c stores the NC machine name, NC machine shape, and maximum load allowable value S.

The processing condition determining means 102 selects the processing condition data from these in response to an operation command or the like, and determines the processing conditions required for NC data creation. The processing condition determining means 102 includes the target set value of the load current of the spindle motor 24 shown in the above-described embodiment. Target set value calculation means 102 a for calculating P is provided. The target set value calculation means 1002a uses the allowable load factor T of the tool 7, the load factor ワーク of the workpiece 6, and the maximum allowable load value S of the machine C from the processing condition data storage means 101. Then, the target set value Ρ of the load current is calculated by the following equation (1).

P = T x S xM----(1)

The NC data creating means 103 creates the NC data 104 based on these processing conditions. The NC data creating means 103 also creates a feed speed control command code G 0 1.0 including the target set value P calculated by the target set value calculating means 102 a.

Figure 6 is a block diagram of the hardware of an automatic programming device having such a function. The processor 111 controls the entire automatic programming device according to a system program stored in the ROM 112. The ROM 112 stores data such as shape information in addition to a system program for controlling the entire automatic programming device. RAM I 13 has an internal

—Evening, Stores various data such as system programs loaded from the floppy disk 1 19a, drawings and machining shape data for creating NC data.

The graphic control circuit 114 converts the NC data stored in the RAM 113 and the data such as the shape of the work into display signals and sends them to the display device 115. The display device 115 displays the NC data or the shape of the workpiece. As the display device 115, a CRT, a liquid crystal display device, or the like is used.

The keyboard 116 is an operation key used for data input and a software key whose function changes depending on the system program. -It has. Evening bracket 1 17 is used to input data such as shape information.

HDD (Hard Disk) Drive 118 stores data to be saved even after the power of the automatic programming device is turned off, such as system information such as parameters and NC data. You. Further, the HDD 118 is provided with most of the processing condition data storage means 101 described above. The FDD (floppy disk drive) 119 drives the floppy disk 119a to input the NC data, or the corrected NC data to the floppy disk drive. · Can be output to disk 1 19a. The created machining shape and NC data can also be output to a plotter 120 and a printer ZPTP (paper tape puncher) 121. These components are connected to each other by a bus 110.

Furthermore, by connecting this automatic programming device to a numerical control device via a communication line or the like, it is possible to send the created machining shape and NC data directly to the numerical control device.

As described above, in the present invention, the numerical control device detects the rotational load of the spindle that drives the rotation of the tool and controls the feed rate of the tool according to the detected rotational load. Even if the magnitude of the load applied to the tool changes depending on the machining shape, the tool can always be moved at the optimum feed rate.

On the other hand, as an automatic programming device, the target set value of the rotational load is calculated based on machining condition data such as tool data and workpiece material data, and the tool is sent so that the calculated target set value is maintained. Send the feed speed control finger code to command the speed control. The same effect as described above can be obtained by executing the NC data containing the feed speed control command code on the numerical controller, since it is created by the speed control command code creation means. be able to.

Claims

The scope of the claims

1. In a numerical controller that moves a tool according to a machining program to add a workpiece,

A rotational load detecting means for detecting a rotational load of a main shaft for rotationally driving the tool;

Feed speed control means for controlling the feed speed of the tool according to the detected rotational load,

A numerical control device comprising:

2. The numerical control device according to claim 1, wherein the feed speed control means is configured to control the feed speed so that the detected rotational load becomes a target set value.

3. The numerical control device according to claim 2, wherein the target set value is configured to be code-commanded on the machining program.

4. A machining condition data storage unit that stores machining condition data such as tool data, ark material data, etc. in an automatic programming device that automatically creates machining programs required for the operation of the numerical controller based on various conditions. When,

Target set value calculating means for calculating a target set value of the rotational load based on the machining condition data;

Feed speed control command code creating means for creating a feed speed control command code for instructing control of the feed speed of the tool so as to maintain the calculated target set value;

An automatic programming device characterized by having:

5. Store machining condition data such as tool data and workpiece material data. Processing condition data to be stored, storing means; target setting value calculating means for calculating a target set value of the rotational load based on the processing condition data; and a tool for maintaining the calculated target set value. An automatic programming device having a feed speed control command code creating means for creating a feed speed control command code for instructing a feed speed control; and

A numerical control device comprising: a rotational load detecting unit configured to detect a rotational load of a main shaft that rotationally drives the tool; and a feed speed control unit configured to control a feed speed of the tool according to the detected rotational load. A data line for sending the NC data created by the automatic programming device to the numerical controller;

Numerical control system characterized by having.