JPH0122105B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tool escape control device for letting a tool escape during workpiece machining in a numerically controlled machine tool. This invention relates to a tool escape control device that can be used.

(Prior Art) In order to automatically process workpieces, numerical control of machine tools is being actively implemented. To achieve this numerical control, a numerical control device (hereinafter referred to as an NC device) is used to control the NC processing according to the desired NC machining program.
The device controls the movement of the tools of the machine tool, the table, etc., so that the tools of the machine tool perform desired processing on the workpiece mounted on the table. If any abnormality (such as tool breakage) occurs while the tool is cutting or other processing on the workpiece, the tool should be removed from the workpiece and the machine should be protected from unnecessary machining so that the workpiece is not machined incorrectly. Machines and workpieces are protected from damage.

Conventionally, in order to let the tool escape from the workpiece, the escape direction, escape amount, and escape speed are programmed in advance, and when an abnormality occurs, this program is executed to make the tool escape from the workpiece. on the other hand,
If the tool is released from the workpiece in the normal direction to the tool movement direction, the tool can be separated from the workpiece by the maximum distance given the commanded escape amount, and the tool can be removed from the workpiece instantly. Optimal.

(Problems with the conventional technology) However, in the conventional tool escape technology using a program to release the tool from the workpiece, the escape direction was set to a constant value, so when moving in a straight line, the escape direction could not be set in the normal direction. You can, but
If an abnormality occurs during arc movement or offset movement, the tool cannot be released in the normal direction to the tool movement direction at that time. Also,
The distance for the tool to escape also needs to be set to an optimal value depending on the machining shape of the workpiece, and the speed also needs to be set at an appropriate speed to avoid leaving cut marks on the workpiece.

(Object of the Invention) An object of the present invention is to provide a tool escape control device that can always escape a tool in a direction perpendicular to the previous tool movement direction, regardless of the set tool escape amount and escape speed. be.

(Summary of the invention) In the present invention, the tool and the workpiece are moved relative to each other.
In a machining system in which a numerical control unit periodically gives movement commands to a dimensional drive mechanism to move a tool along a specified path relative to a workpiece to perform machining, the numerical control unit has a control unit for the two-dimensional drive. Provided with a storage means for storing movement commands for the first and second axes,
The first data stored in the storage means when tool escape is required.
and a first and second movement command for moving the tool in a direction perpendicular to the relative movement direction of the tool from the second movement command.
An escape movement command is calculated, and the two-dimensional drive mechanism is driven by this command to move the tool in a direction perpendicular to the relative movement direction. That is, in the present invention, in numerical control (NC), the command path is divided into minute line segments and movement commands are given periodically to move the tool relatively along the command path. A direction (vector) is shown, and this is used to obtain a movement command in a direction perpendicular to the tool movement direction.

(Example) Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 is an explanatory diagram of the present invention. Fig. 1A shows an example of linear movement, where the command path PP1 of the tool CT is divided into minute line segments △v, and this movement command △
v is given to the drive mechanism periodically (e.g. 8 ns),
The tool CT moves relatively on the command path PP1. 1st
Figure B shows an example of circular movement, where the commanded circular path PP2 of the tool CT is divided into minute line segments △v by circular interpolation, and this movement △v is periodically given to the drive mechanism, CT moves relatively on the command arc path PP2. Figure 1C shows an example of offset linear movement, with programmed path PP3.
In contrast, the movement of the tool CT along the offset command path PP4 in which the offset amount increases sequentially is shown, and in this case as well, the command is periodically divided into minute line segments Δv. In this way, the movement command △v is given periodically, and since this movement command is the direction of the tool movement command at that time, it is possible to store this periodically commanded movement command as a vector in the tool movement direction. , the direction of tool movement at that time is known. In the present invention, a movement command in a direction perpendicular to the tool movement direction is created from the stored instantaneous tool movement vector. This will be explained with reference to FIG. Let the vector of the aforementioned minute line segment be △v, the component in the first axis direction (for example, the X-axis direction) of the two-dimensional movement be v ₁ , and the component in the second axis direction (for example, the Y-axis direction) be v ₂ do. The vector in the vertical direction is q, the component in the first axis direction is q ₁ , and the component in the second axis is q 1 .
Let the axial component be q ₂ .

That is, △v→=(v ₁ , v ₂ ) q→=(q ₁ , q ₂ ) (1) Here, from the well-known law of vectors, △v→・q→=0 (2) ∴v ₁ q ₁ +v ₂ q ₂ = 0 Therefore, q ₂ /q ₁ = −v ₁ /v ₂ (3) Here, since q = √ ² ₁ + ² ₂ , transforming equation (3), q ² ₂ = (−v ₁ /v ₂ ) ² ×q ² ₁ q ² ₂ = (−v ₁ /v ₂ ) ² × (q ² −q ² ₂ ) ∴q ₂ =q*v ₁ /√ ² ₁ + ² ₂ (4) Similarly, q ₁ = q×(−v ₂ )/√ ² ₁ + ² ₂ (5).

Therefore, if the length of the vector q, that is, the escape distance is given from equations (4) and (5), the vertical movement commands q ₁ and q ₂ can be obtained from the vector △v (v ₁ , v ₂ ). can. In reality, the length of q (amount of escape) and the speed of escape F are given in advance by a program, and when escape is required, this program is read and q ₁ and q ₂ are determined.

For example, as this command and G code, G47
(G48) It can be given in the form of QqFf. Furthermore, G47 commands escape to the left in the direction of travel, and G48 commands escape to the right in the direction of travel. Therefore, at the time of interrupt, execute the above program to find q ₁ and q ₂ from equations (4) and (5), and then move the tool in the normal direction (vertical direction) to the moving direction using the escape speed f. It is possible to escape by a distance q at a speed f.

FIG. 3 is a block diagram of an embodiment of the present invention.
In the figure, 101 is a paper tape perforated with numerical control (NC) command data, which stores NC command data such as positioning information for processing and M, S, and T function information; NC) device reads NC data from a paper tape 101 using a tape reader (to be described later), decodes the read NC data, and sends a power board (not shown) for M, S, T function commands, etc. If it is a movement command XC or YC, it is output to the subsequent pulse distributor. The NC device 102 includes a processor 102a that executes arithmetic processing according to a control program, a program memory 102b that stores a predetermined control program, a data memory 102c that stores data, an operation panel 102d for operation, and a tape. Reader/puncher 102e and input/output ports 102f, 102g
, the current position counter 102h, and the display device 10
2i, and an address/data bus 102j that connects them.

The program memory 102b is composed of a read-only memory (ROM) or a nonvolatile memory, and stores a numerical control program and a tool escape control program for numerically controlling the machine tool SCM. On the other hand, the data memory 102c is composed of a non-volatile memory, and is
Movement command storage area that stores movement commands △X, △Y in addition to storing data (machining position data, etc.)
PM is provided.

Reference numeral 103 denotes a pulse distributor, which executes a known pulse distribution calculation based on the movement command ΔX to generate a distribution pulse Ps of a frequency corresponding to the command speed. 104 is a known acceleration/deceleration circuit that linearly accelerates the pulse speed of the distribution pulse train Ps when the pulse train is generated and linearly decelerates it at the end of the pulse train to generate the pulse train Pi; 105 is a table;
X-axis motor for sending TB in the X-axis direction, 106
1 is a pulse coder that generates one feedback pulse FP every time the X-axis motor rotates a predetermined amount.
Reference numeral 07 denotes an error calculation storage unit, which is composed of, for example, a reversible counter, and stores the number of input pulses Pi generated from the acceleration/deceleration circuit 104 and feedback pulses.
Memorize the FP difference Er. As shown in the figure, this error calculation storage unit includes an arithmetic circuit 107a that calculates the difference Er between Pi and FP, and an error register 107b that stores Er.
It may be composed of That is, the error calculation storage section 10
7, the X-axis motor 105 is commanded to rotate in the forward direction, and if it is rotating accordingly, the input pulse Pi is counted up each time the input pulse Pi is generated, or the feedback pulse FP is Each time a pulse occurs, its contents are counted down, and the difference Er between the number of input pulses and the number of feedback pulses is stored in the error register 107b. 108 is a digital-to-analog (DA) converter that generates an analog voltage proportional to the contents of the error register 107b;
9 is a speed control circuit. In addition, the pulse distributor 10
3. The acceleration/deceleration circuit 104, pulse coder 106, error calculation storage section 107, DA converter 108, and speed control circuit 109 constitute an X-axis drive circuit XDV, and a Y-axis drive circuit with the same configuration is also provided on the Y-axis side.
YDV is provided. 110 is a Y-axis motor, which is driven by the Y-axis drive circuit YDV connected to the input/output port 102f to move the table TB to Y.
It is driven in the axial direction, TB is a table, the workpiece is mounted, and the X-axis and Y-axis motors 10
5 and 110 are two-dimensionally driven in the X-axis and Y-axis, and CT is a tool that is composed of a cutter or the like and is driven in the Z-axis direction.

Next, the operation of the embodiment configuration shown in FIG. 3 will be explained.

First, prior to processing, the tape reader puncher 102e reads the NC data of the paper tape 101,
The NC data of the paper tape 101 is stored in the data memory 102c via the bus 102j. Next, a start command is issued to the bus 102 by operating the operation panel 102d.
When the processing control programs are input to the processor 102a through the program memory 102b, the processor 102a sequentially reads and executes the machining control programs from the program memory 102b. That is, the NC data in the data memory 102c is read out, necessary parameters are read out, and the tool CT
In order to machine the workpiece on the table TB into a specified shape, an X-axis movement command ΔX and a Y-axis movement command ΔY are calculated to move the tool CT relative to the table TB along a specified path. As mentioned above, the designated path is controlled by being divided into minute line segments △v by linear interpolation and circular interpolation, so the processor 102a calculates △X, △Y according to the minute line segments △v.
Calculate.

These ΔX and ΔY are stored in the storage area PM of the data memory 102c via the bus 102j. On the other hand, ΔX is supplied to the input/output port 102g, and ΔY is supplied to the input/output port 102f. Now, the movement command is sent from the input/output port 102g to the pulse distributor 103.
, the pulse distributor 103 executes a pulse distribution calculation based on the movement command ΔX and outputs a distribution pulse Ps. The acceleration/deceleration circuit 104 receives this distributed pulse Ps, accelerates or decelerates the pulse speed, and inputs a command pulse train Pi to the error calculation storage section 107. As a result, the contents of the error register 107b are no longer zero, so a voltage is output from the DA converter 108, and the speed control circuit 109 controls the motor 1.
05 is driven, and the table TB is driven in the X-axis direction. When the motor 105 rotates by a predetermined amount, a feedback pulse FP is generated from the pulse coder 106 and stored in the error calculation storage section 107, and the difference Er between the number of command pulses Pi and the number of feedback pulses FP is stored in the error register 107b. will be memorized. Thereafter, the motor 105 is servo-controlled so that the error Er becomes zero, and the table TB is moved by the minute line segment Δv along the X axis. Similarly, △Y is the Y-axis drive circuit YDV from the input/output port 102f.
is given, and the Y-axis motor 110 is driven to move the table TB by the minute line segment Δv on the Y axis, so the table TB moves by the minute line segment Δv. These △X and △Y are given periodically according to the command path, and are stored in the storage area of the data memory 102c.
PM is rewritten and given to the X-axis and Y-axis drive circuits XDV, YDV, thus
The Y-axis motors 105 and 110 are driven, so that the tool CT moves relative to the table TB on the command path. As a result, the workpiece (not shown) on the table TB is machined into the commanded shape by the tool CT.

Now, if an abnormality such as tool breakage occurs and it is necessary to perform a tool escape operation, the NC device 1
The processor 102a of 02 detects this and executes the alarm processing program. That is, the processor 102a interrupts the execution of the numerical control program for machining and executes the tool escape control program. As a result, the processor 102a reads out ΔX and ΔY in the storage area PM of the data memory 102c, as well as the escape amount q and escape speed f given as parameters, and calculates the above equation (4).
Execute equation (5) and move command △ for tool escape.
XE (= q ₁ ) and △YE (= q ₂ ) are calculated, and the bus 102
via j, △XE to input/output port 102g, △
Give YE to the input/output port 102f. This allows the x-axis drive circuit XDV and the Y-axis drive circuit to
YDV is the X-axis motor 105 and Y-axis motor 11, respectively.
0 is driven, the table TB is driven, and as a result, the tool CT is relatively moved perpendicularly (normal direction) to the relative movement direction during machining, and the tool CT is released from the workpiece. After that, the tool CT is left as is or returned to its origin, an alarm is issued, and the operator waits for instructions.

Although the present invention has been described above using one embodiment, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the gist of the present invention, and these are excluded from the scope of the present invention. isn't it.

(Effects of the Invention) As explained above, according to the present invention, axis movement commands are periodically output to the first and second driver circuits that drive the two-dimensional drive mechanism, and the tool is moved between the tool and the workpiece. In a tool escape control device that automatically releases the tool during machining by moving it relative to
a command means for commanding the escape amount and escape speed of the tool; a storage means for storing axis movement commands for the first and second driver circuits; and a command means for commanding the escape amount and escape speed from the command means when tool escape is necessary. calculation means for calculating an escape movement command perpendicular to the relative movement direction from the speed and the movement command of the storage means; and outputting the escape movement command in place of the axis movement command to the first and second driver circuits, respectively. Since the two-dimensional drive mechanism is driven to move the tool in a direction perpendicular to the relative movement direction up to that point when the tool escapes, if the relative movement of the tool is only with a constant movement vector, First, the tool can be moved away from the workpiece in the normal direction even when the relative movement is in a circular arc or in a straight line with a variable offset.

In addition, regardless of the relief amount set by the machining shape of the workpiece or its speed, the tool can always escape in the direction perpendicular to the tool movement direction up to that point, which prevents cut marks from being left on the workpiece. It is possible to prevent unnecessary machining on the machine and prevent unnecessary force from being applied to the machine.

Moreover, since it uses the movement command currently being processed, it not only has the effect of allowing the tool to be released accurately and automatically, but also has the effect of allowing the tool to be released easily and easily, which is better than before. The present invention also has an excellent practical effect in that it can function as a tool escape control device without adding any special device to the numerical control device.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of the principle of the present invention, and FIG. 3 is a block diagram of an embodiment according to the present invention. In the figure, 102... numerical control device, 102C...
Data memory, XDV, YDV...drive circuit,
105...X-axis motor, 110...Y-axis motor,
TB...table, CT...tool.

Claims (1)

[Claims] 1. A tool that periodically outputs axis movement commands to the first and second driver circuits that drive the two-dimensional drive mechanism, and automatically releases the tool during machining by moving the tool relative to the workpiece. The run-off control device includes command means for commanding the run-off amount and speed of the tool, storage means for storing axis movement commands for the first and second driver circuits, and commands from the command means when tool run-off is necessary. calculation means for calculating an escape movement command perpendicular to the relative movement direction from the escape amount and escape speed and the movement command of the storage means;
and an output means for outputting the escape movement command to the first and second driver circuits in place of the axis movement command, so that the tool is moved in a direction perpendicular to the previous relative movement direction when the tool escapes. A tool escape control device featuring: