KR830001480B1 - Tool choice system at numerical control machine tool - Google Patents

Abstract

A numerical control machine tool system comprises a munerical tool having a chuck for helping a workpiece, a cross-slide for holding a plurality of tools adapted to be sequentially selected for use upon the workpiece, a numerical control unit for controlling movement of the cross-slide along at least two axes relative to the workpiece and present position coordinate bvalue registers contained in the numeric control unit for storing the present position coordinate values relative to reference point of the edge of whichever tool has been selected for use upon the workpiece, characterized in that the numerical control unit.

Description

Tool Selection Method for Numerical Control Machine Tools

1 is a schematic plan view of a typical typical CNC machine tool system.

FIG. 2 is a partial plan view for explaining a so-called G function relating to tool No. 1 of the machine tool 11 shown in FIG.

3 is a partial plan view for explaining a so-called G function relating to tool No. 2 of the machine tool 11 shown in FIG.

4 shows a typical conventional tape format of the command tape 23 shown in FIG.

5 is a block diagram of a CNC machine tool according to the present invention.

6 is a plan view of a crossslide with a tool used to illustrate the present invention.

7 is also a plan view of a crossslide with a tool used to illustrate the invention.

The present invention generally relates to a method of selecting a tool of a computerized numerical control machine system, and more particularly, to a method of determining the coordinates of each tool used in such a computerized numerical control machine tool.

Computers and numerically controlled machine tools (hereinafter referred to as CNC machine tools) are very useful for automatically producing any product at low cost with high precision and high reliability.

In a CNC machine tool, various tools are provided on a so-called cross slide, and are arranged at predetermined intervals in a vertical direction on the spindle motor side used to rotate a workpiece to be cut by a selected tool. The selection of the desired tool is performed by punching the corresponding tool number on the command tape, ie punched tape.

One of the important parts for producing the product, the command tape, is used to input the program of the CNC machine tool. The program includes information for performing serial production and various data corresponding to the design of the product.

One of the most important processes of the CNC machine tool is to determine the coordinates of each tool, in particular the edge of each tool. In the prior art for determining the coordinates of the tool tip, the so-called G function of the program is performed whenever a desired tool is designated.

The program G function is identified by the program code "G50" specified in the Japanese CNC standard.

The program code "G50" corresponds to, for example, the program code "G92" designated by the EIA (Electronic Industries Association in U.S.A). This G function is performed for the purpose of matching the origin of the coordinates in the machine tool with the origin of the coordinates of the program.

This, of course, requires punching both the G function program code and the tool tip coordinate values with respect to the command tape whenever a tool number is specified. Therefore, the operator becomes very cumbersome to program, especially when many tools are used in CNC machine tools and when the exchange of exchanges is very troublesome for CNC machine tools. It is therefore an object of the present invention to provide a unique method for matching the coordinates of a selected tool tip in a machine tool and its coordinates in a program and in facilitating a program writing process therefor. Moreover, this unique method can increase the production rate of CNC machine tools.

EMBODIMENT OF THE INVENTION Below, this invention is demonstrated according to an accompanying drawing.

1 is a schematic plan view of a typical CNC machine tool.

In FIG. 1, the CNC machine tool 10 is comprised of the machine tool 11 and the numerical control apparatus (CNC) 12 incorporating a computer. The machine tool 11 cuts the workpiece 20 under the control of the command signal supplied from the numerical controller 12 through the signal line 13. In the machine tool 11, the table 14 is located on the bed 15 of the machine tool 11.

The table 14 is slidable on the bed 15 along the Z-axis (see arrow Z) by means of a lead-skout 16 and a bowl nut (not shown).

When the lead screw 16 is driven by the servomotor 17Z (SZ), the table 14 moves back and forth along the Z axis with the cross slide 18. The cross slide 18 is located on the table 14.

The cross slide 18 is enabled to act on the table along the X axis (see arrow X) by means of a lead screw (not shown) and a bowl nut (not shown).

When the lead screw is driven by the servo motor 17X (SX), the cross slide 18 moves back and forth along the X axis. On the cross slide 18, four kinds of tools, 19-1, 19-2, 19-3, and 19-4, are arranged along the X axis at predetermined intervals.

The workpiece 20 to be cut by any of the tools 19-1-19-4 is firmly gripped by the chuck 21. The chuck 21 and also the workpiece 20 are rotated by the spindle motor 22 (SPM).

The axes of rotation of the workpiece 20, the chuck 21 and the spindle motor 22 are aligned parallel to the respective axes of the tools 19-1 to 19-4. The numerical control device 12 receives information from the command tape 23, and thus the servomotor 17Z via the signal line 13. Control signals are provided to the servo motor 17X and the spindle motor 22, respectively.

Conventionally, the method of matching the coordinates of the tool tip in the machine tool 11 with the coordinates of the tool tip determined in the program is as follows.

In FIG. 2, when the tool number No. 1 corresponding to the tool 19-1 is designated, the information about the distance difference between the reference point PO and the tip 25 of the tool 19-1 is indicated by the command tape ( 23) (FIG. 1).

This difference is measured as the number of control pulses, for example, X = 30,000 Z = 40,000 when the cross slide 18 is reset to its origin before the operation of the CNC machine tool.

The reference point PO corresponds to the central origin of the chuck 21 for grasping the workpiece 20, and at the same time the reference point PO corresponds to the origin of the coordinates in the program.

Next, a program for machining the workpiece is prepared on the command tape. That is, the following two data blocks 1 and 2 are formed on the command tape.

(1) T1 * (2) G50 × 60000Z40000 *

Here, the Ti Ti indicates that No. 1 is assigned, the Corde * indicates the end of the data block, the Cored G50 indicates that the G function should be performed, and the Cored X60,000 Corresponds to a double value of the number 30,000 shown in FIG. 2, and the code Z40,000 corresponds to the number 40,000 shown in FIG.

When the numerical control device 12 (FIG. 1) receives information about the data block 1 from the command tape, the device 12 confirms that one of the tools corresponding to the tool No. 1 is designated. .

Next, the values 60,000 and 40,000 are stored in the current position coordinate value register (not shown in FIG. 1, but shown in FIG. 5). The third data block 3 of the next command tape includes a so-called absolute command, for example,

(3) G00X15000Z18000 *

Here, the code | cog G00 points to a position control command, and the code | coder X15000Z18000 points out the position corresponding to the coordinate (X, Z) value to which the tip of a tool changes.

In the numerical control device 12 (FIG. 2), the incremental command value Vi is calculated by subtracting the present position value Vp from the absolute command value Va. That is, Vi = Va-Vp

The Vp value for the X axis corresponds to the value 60,000 and the Va value corresponds to the value 15,000.

Similarly, the Vp and Va values for the Z axis correspond to phase numbers 40,000 and 18,000, respectively.

Both the incremental command value Vi for the X axis and the incremental command value Vi for the Z axis are both not shown in the interpolator (Fig. 1) in the numerical control device 12 (Fig. 1). (As shown in).

Similarly, if tool 19-2 is designated in FIG. 3, a program for machining the workpiece 20 is formed on the command tape.

That is, the following two day blocks 1 and 2 are formed on the command tape.

(1) T2 *

(2) G50X14000Z20000 *

Here, code T2 indicates that tool No. 2 is assigned. The codes G50X14000Z20000 and * have already been described above.

As described above, in the prior art, a data block indicating the program code, that is, [G50X... Z… *] Must be formed on the command tape whenever the desired tool is specified.

An example of the tape format of the command tape is shown in FIG.

As is apparent from the tape form of FIG. 4, the information indicated on the data block indicated by the reference values 31, 32, 33, 34, 35, etc., must be formed on the command tape each time a desired tool is designated. As a result, the operator sets the G50X… on the command tape whenever a tool change occurs. Z… It is very cumbersome to set up a program because you need to include a * data block.

However, in the present invention, [G50 X... Z… Since all data blocks of *] can be omitted from the program, the driver is more convenient in setting the desired program. From the program [G50 X…] Z… In order to omit the data block of *], all the tools indicating the difference between the leading edge of each tuol and the origin of the coordinates in the program (refer to PO in FIG. 2 or FIG. 3) in the present invention. The coordinates of the current position of are in the memory of the present invention.

When the one-to-one number (refer to T1, T2, T4, etc. of FIG. 4) is designated by the command tape 33 (FIGS. 1 and 4), the corresponding coordinates (X, Z) are stored from the storage device. The corresponding coordinates (X, Z) are then set in the current position coordinate value register of the numerical controller.

5 is a configuration diagram of the CNC machine tool of the present invention, which is obtained from the command tape. Z… Used to omit prior art data blocks of *.

However, FIG. 5 describes only the members used to carry out the method of the present invention, and the conventional members are not shown here. The CNC machine tool 40 of the present invention is a numerical control device 41 which controls the machine tool 11 (MT) (FIG. 1) by the servo motors 17X and 17Z (FIG. 1). Consists of.

The servo motor 17X is rotated in the front-rear direction by the servo control circuit 42X (SCX).

The servo motor 17Z is rotated in the front-rear direction by the servo control circuit 42Z (SCZ). The numerical control device (41) includes a central operation control device (43) (CPU), a storage device (44), a tape reader (45) (TR), a tape reader control circuit (46) (TRC), and a manual data input device. (47) (MDI), digital data input device 48 (DI), interpolator 49 (INT), and the servo control circuits 42X and 42Z.

In addition, the central processing unit 43, the storage unit 44, the tape reader control circuit 46, the manual data input unit 47, the digital data input unit 48, and the interpolator 49 are address and data buses. (bus) 50 (ADB) are all interconnected.

The memory device 44 is composed of a first memory area 44-1, a CPM, a second memory area 44-2 (RA), and a third memory area 44-3 (CDA). The first storage area 44-1 stores the control program. The second storage area 44-2 stores a tool number, an absolute command value, a current position coordinate value and an incremental command value of the tool tip.

The third storage area 44-3 stores data indicating the relationship between the respective tool number and the coordinates (X, Z) of the corresponding tool. In more detail, the second memory area 44-2 includes registers RT, RXA, RZA, RXe, RZa, RXI, and RZI, and RZI. ) Stores the specified tool number, register RXA stores the absolute command value (XA) for the X axis, register RZA stores the absolute command (ZA) for the Z axis, and register RXa is the coordinate value (Xa) of the tool tip. ), Register RZa stores the coordinate value Za of the tool tip, register RXI stores the incremental command value XI for the X axis, and register RZI stores the incremental command value ZI for the Z axis. . In more detail, the third region 44-3 is divided into regions RT1 to RTN.

The divided areas RT1 to RTN correspond to tool numbers No. 1 to No. N, respectively, when the N number of the tool is used for the machine tool 11. Each area divided by (RT1) to (RTN) consists of two registers.

One of the registers is X1, X2,... The value of the X coordinate of the corresponding tool tip, such as Xn, is stored, and other registers store the values Z1, Z2. Remember the Z coordinate value equal to Zn.

The manual date input device 47 is used as input data for displaying a tool number and a coordinate (X, Z) value of a tool tip corresponding to the tool number, respectively.

Coordinate (X, Z) values are usually dependent on the plant using the CNC machine tool. In this case, the tool number is set manually using the number switch 47-1.

The address switch 47-2 is used to select either the X axis CX or the Z axis CZ.

The data key 47-3 is used to input the value of the coordinate X and the coordinate Z value of each tool tip.

The transmission key 47-4 is used to convert data, which is collected by the members 47-1 and 47-4 with respect to the address and data bus 50.

The first display 47-5 checks the input value of the coordinate X and the input value of the coordinate Z. The second display 47-6 checks the designated tool number. The digital data input device 48 has a mode selection switch 48-1.

The "Manual Data Input" (MDI) mode or the "Command Data Control" (TAPE) mode can be selected by fitting the switch 48-1 to the MDI terminal or TAPE terminal.

The interpolator 49 is composed of a first register RXII and a second register RZII. The first register RXII stores the incremental command value XI for the X axis.

The second register RZII stores the incremental command value ZI for the Z axis. Then, using a known process, the interpolator 49 is connected to the servo control circuits 42-X and 42-Z according to the stored incremental command values XI and ZI corresponding to the X and Z axes, respectively. Distribute the control pulse.

Thus, the table 14 (FIG. 1) and the cross slide 18 (FIG. 1 in the machine tool) move the desired position according to the design of the product. Operation for the CNC machine tool shown in FIG. Same as

(1) The tool number and the value of the coordinates (X, Z) of the tool tip corresponding to the number are stored, where the cross slide is reset to its origin.

(a) In the digital data input device 48, the mode selection position 48-1 is initially set in the "manual data input" (WDI) mode. Next, the MDI mode control program is called from the first memory area 44-1 in the storage device 44.

(b) In manual data input device 47, tool number is designated by pressing number switch. The tool number may be represented by, for example, two numbers d1 and d2 displayed on the switch 47-1. The designated tool number is displayed for confirmation on the second display 47-6.

(c) The X axis is designated by setting the address switch 47-2 at the CX terminal.

(d) The coordinate (X) value of the tool tip corresponding to the tool specified in step (b) is input by pressing the numeric indications 1-9 displayed on each data key 47-3. These numbers are shown for confirmation on the first display 47-5.

(e) After confirming the numbers shown on the display (47-5) and (47-6), press the transmit key (47-4).

Next, the coordinate X value of the tool tip corresponding to the designated tool number is transferred to the third storage area 44-3 of the storage device 44 and stored therein.

If the tool No. 1 is designated and the coordinate X value is X1, the value X1 is stored in one of the registers RT1.

(See 3rd memory area in Fig. 5)

(f) The Z axis is designated by setting the address switch 47-2 in the terminal C2, which setting is the same as that in step C above.

(g) The coordinate Z value of the tool corresponding to the tool number specified in the step (h) is input by pressing the numeric indicator displayed on each of the data keys 47-3. The number is displayed on the first display 47-5 for confirmation as in step (d).

(h) After the numbers are confirmed by the displays 47-5 and 47-6, press the transmit key 47-4.

Then, the coordinate Z value of the tool tip corresponding to the designated tool number is transmitted to the third storage device 44-3 and stored therein as in step (e) above. If the coordinate Z value is Z1, the Z1 value is then stored in the other one of the registers RT1.

The tool number of the remaining tool and the coordinates (X, Z) of the tool tip are also stored in the third storage area 44-3 in the same steps as the above steps (a) to (h).

)에 의하여 제공된 프로그램의 실행(1)(2) Command tape (2

Execution of a program provided by

(II) The mode selection switch 48-1 in the digital data input device 48 is next set in the "command tape control" (TAPE) mode, and then the control program for the TAPE mode is stored in the storage device 44. It is called from the first memory area 44-1.

(III) The CPU 43 instructs the tape reader gear circuit 46 to automatically start the tape reader 45.

After that, the tape reader 45 is operated to read out the data recorded in the command tape 23. The tape format of the read data is the same as the conventional tape format shown in FIG.

However, in the tape configuration of the present invention, it is not necessary to use conventional data blocks 31, 32, 33, 34, 35, and the like. Operations corresponding to these blocks 31, 32, 33, 34, 35, etc. are all replaced by only one initial setting of data performed according to the above steps (a) to (h). do.

(III) The conventional tool selection command code such as T1 * is read from the command tape. The code T1 designates the tool No. 1.

The number of this tool No. 1 is transferred to the register RT in the 2nd memory area 44-2, and is stored in it. Since the tool No. 1 is specified here, the address in the storage device 44 which stores the coordinates (ie: X1, Z1) values of the tool tip corresponding to the built-in tool No. 1 is set according to the control program for TAPE mode right. 43) are ordered. The coordinate (X1, Z1) values are subsequently read out from the storage area 44-3 corresponding to the commanded address.

The read coordinates X1 and Z1 are transferred to registers RXa and RZa, respectively, and stored therein. Therefore, the present position coordinate values (X, Z) of the registers RXa and RZa are replaced by the open coordinate values X ₁ , Z ₁ .

In this step, the process for determining the coordinates (X, Z) of the tip of the tool No. 1 is completed.

(IV) The absolute command value corresponding to the next tool No. 1 is read from the command tape.

The read absolute command value XA corresponding to the X axis and the read absolute command value ZA corresponding to the Z axis are stored in the registers RXA (RZA) in the second storage area 44-2, respectively.

(V) The incremental command value XI is derived from the following equation by a known computing circuit (not shown).

XA-Xa = XI

The value of Xa is the current position coordinate value stored in the register RAa during the above step (III). In this step, the Xa value corresponds to X1.

The derived increment command value XI is stored in the register RX1 in the next second storage area 44-2. Similarly, the incremental command value ZI is represented by the following equation by a known calculation circuit (not shown),

ZA-Za = ZI

Derived from.

Za value is a register during step (III) above.

(VII) The interpolator 49 distributes control pulses to the servo control circuits 42X and 42Z, respectively, in accordance with the incremental command values XI and ZI.

Thus, the designated tool is moved along the desired route in the machine tool 11 by the servomotor 17X and 17Z table 14 (FIG. 1) and the cross slide 18 (FIG. 1).

In this step (VII), whenever the control pulse is applied to the servo control circuit 42X or 42Z, the current position coordinate values Xa and (Za) in the registers RXa and (RZ) are It is updated by adding +1 and -1 one by one. In the above steps (a) to (h) and (II) to (VII), the current position coordinates of all the tool tips are absolute values for the origin PO (FIGS. 2 and 3), for example, a register ( Absolute values stored in RT1, RT2, ... RTn),

Is displayed.

However, the current position coordinate value of the tip of the tools may be raised by the relative value with respect to the reference tool corresponding to the reference tool, for example tool No. 1, not with respect to the origin PO (second or third degree). In this case, the relative value

Are stored in registers RT1, RT2 ... RTn, respectively.

As shown by 19-1 to 19-4 in FIG. 1, if four tools are present, the relative value is represented by X2 ', Z2', X3 ', X4', Z4 'as shown in FIG. .

In this case, if tool No. 2 is exchanged for tool No. 4, then the difference of values X4'-X2 'and the difference of values Z4'-Z2' are stored in the value Xa stored in register RXa and register RZa. Each added value is added to Za.

The sum of the stored value Xa and the difference between the values (X4'-X2 ') and the sum of the stored value Za and the difference between the values (Z4'-Z2') is the current position coordinate value of the tip of the tool No. 4. Indicates.

In other cases for the four tools shown in FIG.

(0,0) of tool No.1 (X2 ', Z2') of tool No.2

Tool No.3 (X3 ', Z3') Tool No.4 (X4 ', Z4)

Are stored in registers RT1 to RT4, respectively.

(X2 ', Z2')... (X4 ', Z4') is an absolute value with respect to the coordinate value of the reference tool No.1.

In this case, in Fig. 7, if the tool No. 2 is replaced with the tool No. 4, the cross slide 18 has the arrow 61 so that the tip of the tool No. 4 coincides with the tip of the tool No. 2. Operate in the direction indicated by).

The operation of the cross slide 18 takes place by applying a control pulse to the servo control circuits 42X and 42Z (FIG. 5). The number of control pulses applied corresponds to the difference of values X4'-X2 ') and (Z4'-Z2').

Therefore, since the initial operation of the cross slide 18 matches the edge of the tool No. 4 to the edge of the final tool No. 2, the value Xa stored in the present position coordinate value registers RXa and RZa shown in FIG. ) And (Za) do not need to be updated.

In this case, a suitable gate circuit must be newly placed at the input terminals of the resistors RXa and RZa.

Since the gate circuit is closed when the operation of the cross slide is being performed, the difference of values (X4'-X2 ') and (Z4'-Z2') is prevented from being applied to the registers RXa and RZa. If a suitable gate circuit is not located at the input terminals of registers RXa and RZa for some particular reason, the difference of values (X4'-X2 ') and (Z4'-Z2') will be applied to registers RXa and RZa. Therefore, the current position stored in the registers RXa and RZa corresponding to the tool No. 2 is changed unintentionally.

This is because the stored value should not be changed in this case, and the actual position of the tip of tool No. 4 should be moved only to the final position where the tip of tool No. 2 is located.

However, the difference in values (X4'-X2 ') and (Z4', Z2 ') are also added to the registers RXa and RZa, respectively.

Therefore, in this case, it is necessary to subtract the teeth (X4'-X2) and (Z4'-Z2 ') from the teeth Xa of the register RXa and the teeth Za of the register RZa, respectively. Reaches the final position located at the tip of tool No. 2, the position where tool No. 2 has finished its work.

As mentioned above, only cutting tools with tools arranged on the comb have been described in connection with the first, second, third, sixth and seventh degrees as embodiments of the present invention.

However, conventional rotary tool posts can also be employed in the machine tool according to the present invention.

As described above, a typical conventional program code " G50X ... Z * " which must be prepared each time a tool change is made can be omitted in the program of the present invention.

As a result, the driver can more easily write a program.

Claims (1)

A machine tool having a work holding device and a cross slide and having a plurality of tools attached to the cross slide, and a numerical control device for controlling relative movement along at least two axes of the work piece of the cross slide; In the numerical control operation, the numerical control device is provided with a current value register for storing the current value of the tool edge position. The tip position data of each tool is stored in a storage device provided in the numerical control device, corresponding to each tool number of the tool, and when a predetermined tool number is commanded, the tip position data is written to the tool number. A tool selection method for a numerically controlled machine tool, characterized in that the contents of the present value register are corrected by the difference between the corresponding tip position of the corresponding tool and the tip position of the tool used so far.

Images