JP2009075727A - Numerical controller, numerical control program, and storage medium storing numerical control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a numerical controller and a numerical control program, preventing work damage in operation for confirming a machining program. <P>SOLUTION: In this numerical controller, dry-run operation is turned on, and an offset amount is determined in time of the first execution of the NC program. Zmax is set to "0", a pre-movement position is set to "0", and the NC program is interpreted from the first line of the NC program (S11, S12). When there is an instruction to move in a Z-axis direction (S13: YES) and when there is a cut movement instruction of a Z-axis (S14: YES), a movement amount of cut movement "the pre-movement position-coordinates of a movement destination of the cut movement instruction" is stored in Zmv (S15). When Zmv>Zmax (S16: YES), Zmv is stored in Zmax (S17). The coordinates of the movement destination are stored in the pre-movement position (S19), and a block of an interpretation target is advanced (S21). It is returned to S12, S12-S21 are repeated until an instruction of a program end, and a maximum movement amount of the cut movement is stored in Zmax. A value of Zmax is stored in the offset amount (S22). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a numerical control device, a numerical control program, and a storage medium storing the numerical control program, and more specifically, a numerical control device and a numerical control program for preventing workpiece damage in an operation for checking a machining program. And a storage medium storing a numerical control program.

Conventionally, a dry run operation in which the machining program is idle is used to check whether the machining program is correct. For example, in the dry run control device in the NC device of the invention described in Patent Document 1, the rise time and the fall time of the movement of the tool are controlled in the dry run mode. Moreover, in the operation control apparatus in the machine tool of the invention described in Patent Document 2, the operation is performed without supplying the coolant in the dry run. Conventionally, dry running is also performed in which the distance between the tool and the workpiece is separated by a predetermined distance (offset amount) rather than the instruction of the machining program. One such offset is stored for each apparatus. However, since the length of the tool used and the height of the workpiece differ depending on the machining program, it is necessary for the operator to input an appropriate offset amount.
Japanese Patent Laid-Open No. 03-144807 Japanese Patent Laid-Open No. 02-1000085

  However, if the value entered by the operator is not appropriate, if the operator makes a mistake, or if the operator forgets to enter the offset amount, the entered value or stored value Depending on the case, there is a problem that the tool comes into contact with the workpiece and damages the workpiece.

  The present invention has been made to solve the above-described problems, and a numerical control device, a numerical control program, and a storage medium storing the numerical control program for preventing workpiece damage in an operation for checking a machining program are provided. The purpose is to provide.

  In order to solve the above-described problem, in the numerical control device according to the first aspect of the present invention, a numerical value for numerically controlling a machine tool that operates a tool held by a spindle and processes a workpiece fixed to a jig based on a processing program. A dry run operation for controlling the tool based on the machining program in a state in which the distance between the tool and the workpiece is separated from the distance specified by the machining program by an offset amount that is a predetermined amount. And a cutting instruction of the machining program for moving the tool or the workpiece in a direction in which the tool and the workpiece approach each other and instructing a cutting operation for cutting the workpiece by operating the tool. Offset amount determining means for determining the offset amount based on a movement start position and a movement end position in To have.

  Further, in the numerical control device according to the second aspect of the present invention, in addition to the configuration of the first aspect, the offset amount determining means is configured to determine whether the movement start position and the movement end position are included in the cutting instruction. Among the differences, the largest difference is determined as the offset amount.

  In addition, in the numerical control device according to the invention of claim 3, in addition to the configuration of the invention of claim 1, the offset amount determination means includes the tool and the workpiece among the movement start positions of the cutting instruction. Is the difference between the farthest movement start position, which is the position in the farthest direction, and the most recent movement end position, which is the position at which the tool and the workpiece are closest to each other among the movement end positions of the cutting instruction. It is characterized by determining to.

  Further, in the numerical control device according to the fourth aspect of the invention, in addition to the configuration of the first aspect of the invention, the cutting to be executed when the instruction to be executed when executing the machining program is the cutting instruction. A next cutting instruction searching unit that searches the cutting program for the cutting instruction to be executed next to the instruction, and the offset amount determining unit includes the movement start position of the cutting instruction searched by the next cutting instruction searching unit; The difference from the movement end position is determined as an offset amount.

  In the numerical control program according to the fifth aspect of the present invention, the computer is operated as various processing means of the numerical control apparatus according to any one of the first to fourth aspects.

  The computer-readable storage medium of the invention according to claim 6 stores the numerical control program according to claim 5.

  In the numerical control device according to the first aspect of the present invention, the tool is operated based on the machining program in a state in which the distance between the tool and the workpiece is separated from the distance specified by the machining program by a predetermined offset amount. When performing the dry run operation, the offset amount can be automatically determined in accordance with the cutting instruction in the machining program. Therefore, the calculation error of the offset amount, the input error of the offset amount, and the forgetting to input the offset amount, which may occur when the operator inputs the offset amount, do not occur. Therefore, the tool and the work do not come into contact with each other due to human error, and the work is not damaged.

  In addition, in the numerical control device according to the second aspect of the invention, in addition to the effect of the first aspect, the offset amount determining means includes the difference between the movement start position and the movement end position in the cutting instruction, The largest difference can be determined as the offset amount. Therefore, since the largest movement amount in the cutting operation is set as the offset amount, when the offset amount is uniformly determined for the machining program, the smallest amount among the safe amounts can be set as the offset amount. it can. Therefore, the distance between the workpiece and the tool is the smallest distance among the safe distances. Therefore, when the operator checks the operation of the machining program, when the workpiece and the tool are visually checked, it is easy to understand which position of the workpiece the tool cuts.

  In addition, in the numerical control device according to the third aspect of the invention, in addition to the effect of the first aspect, the offset amount determining means is a direction in which the tool and the workpiece are farthest from each other in the movement start position of the cutting instruction. The difference between the farthest movement start position that is the position of the most recent movement and the most recent movement end position that is the position at which the tool and the workpiece are closest to each other among the movement end positions of the cutting instruction can be determined as the offset amount. Therefore, the difference between the position where the tool and the workpiece are farthest in the cutting operation and the position where the tool and the workpiece are closest is the offset amount. Can be set.

  In the numerical control device according to the fourth aspect of the present invention, in addition to the effect of the first aspect of the invention, when the instruction to be executed when executing the machining program is a cutting instruction, the cutting instruction to be executed is executed. The cutting instruction to be executed next can be searched from the machining program, and the offset amount determination means can determine the difference between the movement start position and the movement end position of the searched cutting instruction as the offset amount. Therefore, since the offset amount is determined during execution of the machining program, the time loss can be reduced compared with the case where the offset amount is determined by analyzing the entire machining program.

  The numerical control program of the invention according to claim 5 can achieve the same effect as any one of claims 1 to 4 by being executed by a computer.

  Further, in the computer-readable storage medium of the invention according to claim 6, by causing the computer to execute the stored numerical control program, the same effect as that of claim 5, ie, any one of claims 1 to 4 is obtained. Similar effects can be achieved.

  Hereinafter, a first embodiment to a third embodiment of the present invention will be described with reference to the drawings. The numerical control device 1 according to the first to third embodiments is a device that processes a workpiece (workpiece) using a tool. The numerical control device 1 fixes the workpiece, moves the tool, and processes the workpiece by operating it. The command for moving the tool is described in the NC program (see FIG. 2), and the tool is moved and operated by interpreting the NC program line by line. In the numerical controller 1, the NC program is executed by the “dry run operation”, and it is confirmed whether or not the NC program operates correctly. That is, the “dry run operation” is an NC program test operation. In this dry run operation, the work is not actually machined, but the tool is moved away from the work. The distance separating the tool and the workpiece is the “offset amount”. Thereby, the movement of the tool according to the instruction of the NC program can be confirmed without actually machining the workpiece. In the numerical control apparatus of the present invention, this “offset amount” is automatically set based on the NC program.

  Here, the electrical configuration of the numerical controller 1 will be described with reference to FIG. FIG. 1 is a block diagram showing an electrical configuration of the numerical controller 1. This configuration is common to the numerical controller 1 of the first to third embodiments.

  As shown in FIG. 1, the numerical control device 1 is provided with a CPU 10 that controls the numerical control device 1. The CPU 10 is a processor that is the center of control of the entire numerical controller 1, and is connected to the ROM 11, the input interface 12, the output interface 13, and the RAM 14 via the bus 18. The ROM 11 stores a control program for controlling the numerical control device 1. The CPU 10 reads the control program from the ROM 11, and the control program reads the NC program stored in the RAM 14 to execute machining of the workpiece. To do. The RAM 14 also stores temporary calculation data, display data, and the like.

A keyboard 15, a dry run switch 16, and a start switch 17 are connected to the input interface 12. The keyboard 15 can input various information to the numerical controller 1. The dry run switch 16 receives an instruction as to whether or not to operate the numerical control apparatus 1 in the “dry run operation”. If the dry run switch 16 is ON, the numerical controller 1 is operated in “dry run operation”, and if it is OFF, it is operated in “normal operation” that is not dry run operation. That is, if it is OFF, it will operate according to the positional relationship between the tool and the workpiece according to the NC program. The start switch 17 is a switch for instructing execution of the NC program. When turned ON, the NC program is read and a command is executed for each line. The output interface 13 also has a drive circuit 21 for driving the X-axis motor 31 for moving the tool 2 (see FIGS. 3, 6, and 8) in the X-axis direction, and the tool 2 is moved in the Y-axis direction. A drive circuit 22 for driving the Y-axis motor 32 for driving, a drive circuit 23 for driving the Z-axis motor 33 for moving the tool 2 in the Z-axis direction, and a spindle motor 34 for rotating the spindle of the tool 2. A control circuit 25 for controlling the drive circuit 24 and the display device 35 is connected.

  Next, the NC program will be described with reference to FIG. FIG. 2 is a schematic diagram of the NC program. As shown in FIG. 2, the NC program defines the operation of the tool 2 with one line as one block. In addition, a block number represented by “N” and a number is written at the top of each line. In the example illustrated in FIG. 2, six blocks “N1”, “N2”, “N3”..., “N6” are described. “N1” “Z250”, “N3” “Z200”, “N4” “Z230”, “N5” “Z198” are commands indicating to which position on the Z-axis the tool should be moved. . In the present embodiment, the coordinate system is set so that the numerical value increases in the direction away from the workpiece. In the example shown in FIG. 3, the vertical direction in FIG. 3 is the Z-axis direction, and the coordinate value increases from the bottom to the top in FIG.

  Further, “G0” of “N1” and “N4” is a command for determining the position by moving the tool 2. Therefore, “G0Z230” of “N4” is a command to move the tool 2 to the Z axis 230 (movement command). “G1” of “N3” and “N5” is a command (cutting movement command) for moving the tool 2 in a specified direction while operating. “G90” designates that the coordinate instruction is an absolute value designation method, “M8” is a command to supply cutting oil, and “M30” is a command to end the program.

  The cutting movement command is not limited to “G1”, but includes, for example, “G2”, “G3”, “G102”, “G103”, “G202”, “G203”, “G12”, and “G13”. “G2” is a circular interpolation command or a helical interpolation command for performing cutting while drawing a circle in a clockwise direction. “G3” is a circular interpolation command or a helical interpolation command for performing cutting while drawing a circle counterclockwise. The difference between the circular interpolation command and the helical interpolation command is that the helical interpolation command is cut while moving in the Z-axis direction. The circular interpolation command does not involve movement in the Z-axis direction. “G102” is an XZ circular interpolation command for cutting in a clockwise direction with circular arcs in the X-axis and Z-axis directions. “G103” is an XZ circular interpolation command for cutting in a counterclockwise direction with circular arcs in the X-axis and Z-axis directions. “G202” is a YZ circular interpolation command for cutting in a clockwise direction with circular arcs in the Y-axis and Z-axis directions. “G203” is a YZ circular interpolation command for cutting in a counterclockwise direction with circular arcs in the Y-axis and Z-axis directions. “G12” is a circle cutting command for cutting a circle clockwise. “G13” is a circle cutting command for cutting a circle counterclockwise. What is used in determining the offset amount involves movement in the Z-axis direction. Therefore, in these cutting movement commands, “G1”, “G2”, “G3” are commands for movement in the Z-axis direction, “G102”, “G103”, “G202”, “G203”. .

  Next, the “offset amount” in the first embodiment will be described with reference to FIG. FIG. 3 is an explanatory diagram of a method for determining the offset amount. 3 indicates the movement trajectory of the tip of the tool 2 by the Z-axis movement command (G0), and the solid-line arrow indicates the tip of the tool 2 by the Z-axis cutting movement command (G1). The movement trajectory is shown. In the example shown in FIG. 3, the cutting operation is performed at three locations. The start point of the left cutting movement is SS1 and the end point is SE1, the start point of the center cutting movement is SS2, the end point is SE2, the start point of the right cutting movement is SS3, and the end point is SE3. . The magnitude relationship of the respective movement amounts is the movement amount of the central cutting movement (SS2-SE2) <the movement amount of the right cutting movement (SS3-SE3) <the movement amount of the left cutting movement (SS1-SE1). In the first embodiment, the dry run operation is turned on, and when the first NC program is executed, all NC programs are analyzed, and the amount of movement (cutting distance) in the Z-axis direction in the Z-axis cutting movement command is calculated. Of these, the longest distance is defined as an “offset amount”. Therefore, in the example illustrated in FIG. 3, the movement amount “SS1-SE1” of the left cutting movement is the offset amount.

  Next, the operation of the numerical controller 1 in the first embodiment will be described with reference to the flowcharts of FIGS. 4 and 5. FIG. 4 is a flowchart of the memory operation mode, and FIG. 5 is a flowchart of the offset amount automatic setting process performed in the memory operation mode. The memory operation mode process is a process executed by the CPU 10 when the numerical controller 1 is turned on and set to the memory operation mode. The memory operation mode is a mode in which the NC program is read and the tool 2 is operated in accordance with the NC program command. In addition to the memory operation mode, there is a manual operation mode in which the tool is operated by a manual instruction. These modes can be switched by a mode switch not shown.

  In the memory operation mode process, first, the operation of the start switch 17 is waited. When the start switch 17 is operated, the NC program is read from the RAM 14 and the first block is set as a block to be interpreted (S1). Next, it is determined whether or not the operation is the first start switch 17 after the dry run switch 16 is turned on (S2). For this determination, a dry run activation flag storage area (not shown) provided in the RAM 14 is used. As the dry run activation flag, “1 (ON)” is stored when the dry run switch 16 is turned on. Then, when the dry run switch 16 is turned off or when the start switch 17 is operated in a state where the dry run switch 16 is on, “0 (OFF)” is stored. Therefore, if the dry run start flag is ON, it is determined that the operation is the first start switch 17 after the dry run switch 16 is turned ON (S2: YES). Then, an offset amount automatic setting process is performed (S3, see FIG. 5). In the offset amount automatic setting process, the offset amount is determined based on the NC program. The offset amount automatic setting process will be described later with reference to FIG. If the dry run start flag is OFF and it is determined that the operation is not the first start switch 17 after the dry run switch 16 is turned ON (S2: NO), the offset amount has already been determined. The process proceeds directly to S4.

  When the offset amount is determined by the offset amount automatic setting process, the block to be interpreted is interpreted (S4). It is determined whether or not the block has a command to move in the Z-axis direction (S5). Here, if there is a Z-axis movement command or a Z-axis cutting movement command in the block being interpreted, it is determined that there is a movement in the Z-axis direction (S5: YES). For example, if “G0Zzz”, “G1Zzz”, “G2Zzz”, “G3Zzz”, “G102Zzz”, “G103Zzz”, “G202Zzz”, “G203Zzz”, there is a movement in the Z-axis direction. Note that the lowercase letter z is an arbitrary number, and zzz indicates the coordinate of the movement destination of the Z axis. If the command is to move in the Z-axis direction (S5: YES), the offset amount is added to the coordinate zzz of the movement destination of the Z-axis (S6). Specifically, the coordinate zzz of the movement destination + the value of the offset amount is put on the movement command output to the drive circuit 23 that drives the Z-axis motor 33 that operates the Z-axis. Based on the description of the block to be interpreted, a command is output to the various drive circuits 21 to 24 to execute the operation of the block to be interpreted (S8). Then, the block to be interpreted is moved to the next line (S9), and the process returns to S4. If it is not a command to move in the Z-axis direction (S5: NO), it is determined whether or not it is a program end command (S7). If it is not a program end command (S7: NO), the operation of the block to be interpreted is executed (S8), the block to be interpreted is moved to the next line (S9), the process returns to S4, and the program end command is repeated S4 to The process of S9 is performed. If it is an instruction to end the program (S7: YES), the process returns to S1, and the operation of the start switch 17 is waited (S1).

  As described above, since the Z-axis motor is driven with the offset amount taken into account, the NC program is executed with the distance between the workpiece 3 and the tool 2 separated from the distance specified by the NC program by the offset amount. Is done.

  Next, the offset amount automatic setting process will be described with reference to FIG. As shown in FIG. 5, in the offset amount automatic setting process, first, the variable Zmax and the position before movement are initialized, and the first line of the NC program is set as a block to be interpreted (S11). In the pre-movement position, the maximum value of the movement range in the Z-axis direction is stored. In the first embodiment, “600” is assumed. The initial value of the variable Zmax may be a value equal to or smaller than the minimum value of the movement range of the tool 2 in the Z-axis direction. In the first embodiment, the minimum value of the movement range of the tool 2 in the Z-axis direction is “0”, and the initial value of the variable Zmax is also “0”. These variables are provided with a storage area in the RAM 14. Then, the interpretation target block is interpreted (S12). Then, it is determined whether or not this block has a command to move in the Z-axis direction (S13). Here, if there is a Z-axis movement command or a Z-axis cutting movement command in the block to be interpreted, it is determined that there is a movement in the Z-axis direction (S13: YES).

  If the movement is in the Z-axis direction (S13: YES), it is further determined whether or not it is a Z-axis cutting movement command (S14). For example, if there are “G1Zzz”, “G2Zzz”, “G3Zzz”, “G102Zzz”, “G103Zzz”, “G202Zzz”, “G203Zzz”, it is determined that the command is a Z axis cutting movement command (S14: YES). The amount of cutting movement is calculated and stored in the variable Zmv (S15). The variable Zmv is calculated by “position before movement−coordinate zzz of movement destination of cutting movement command”. Next, it is determined whether or not the variable Zmv is higher than the variable Zmax (S16). In other words, if the movement amount Zmv> Zmax of the cutting movement, it is determined that the movement is longer than the variable Zmax (S16: YES), and the value of the movement amount Zmv of the cutting movement is stored in the variable Zmax (S17). If the movement amount Zmv ≦ Zmax of the cutting movement is determined, it is determined that it is not longer than the variable Zmax (S16: NO), and the variable Zmax is not updated. Next, the coordinate zzz of the movement destination is stored in the pre-movement position (S19).

  Next, the block to be interpreted is advanced by one (S21). Then, the process returns to S12 to interpret the block to be interpreted (S12). Then, it is determined whether or not the block moves in the Z-axis direction (S13). If it is a command to move in the Z-axis direction (S13: NO), it is further determined whether or not it is a Z-axis cutting movement command (S14), and if it is not a Z-axis cutting movement command (S14: NO), the coordinates zzz of the movement destination are stored in the pre-movement position (S19). Then, the block to be interpreted is moved to the next line (S21), and the block is interpreted (S12). If there is no command to move in the Z-axis direction in this block (S13: NO), it is determined whether or not it is a program end command (S20). If it is a program end command (S20: YES), the value of the variable Zmax is stored in the offset amount (S22), and the process returns to the memory mode operation process.

  In the example of the NC program shown in FIG. 2, since “N1” is “G0Z250” (13: YES, S14; NO), “250” is stored at the pre-movement position (S19). Next, in “N2”, since it is “M8”, there is no Z-axis movement command (S13: NO), and it is not a program end command (S20: NO), so no variable is updated. Next, since “N3” is “G1Z200” (S13: YES, S14: YES), the moving amount Zmv of the cutting movement is compared with the variable Zmax (S16). At this time, since the movement amount Zmv of the cutting movement = the position before the movement−the coordinates zzz = 250−200 = 50> 0 = the variable Zmax of the movement destination of the cutting movement command (S16: YES), the variable Zmax is “50”. (S17). Then, the pre-movement position is set to “200” (S19). Next, since “N4” is “G0Z230” (S13: YES, S14; NO), “230” is stored in the pre-movement position (S19). Next, since “N5” is “G1Z198” (S13: YES, S14: YES), the moving amount Zmv of the cutting movement is compared with the variable Zmax (S16). At this time, since the movement amount Zmv of the cutting movement = the position before the movement−the coordinates zzz = 230−198 = 32 <50 = the variable destination of the cutting movement command (S16: NO), the variable Zmax is not updated. The pre-movement position is “198”. Since “N6” is “M30” (S13: NO), it is determined that the program is finished (S20: YES), and the variable Zmax = “50” is stored in “Offset amount” (S22).

  As described above, the dry run operation is turned ON, and when the first NC program is executed, the offset amount automatic setting process is performed, all the NC programs are analyzed, and the Z axis direction in the Z axis cutting movement command is analyzed. Among movement amounts (cutting distances), the longest distance is defined as an “offset amount”. Therefore, since the offset amount is automatically determined based on the NC program, an offset amount calculation error by the operator, an offset amount input error, and an offset amount may occur when the operator inputs the offset amount. There is no forgetting to input. Therefore, the tool and the work do not come into contact with each other due to human error, and the work is not damaged. In addition, since the largest movement amount in the cutting operation is set as the offset amount, when the offset amount is uniformly determined for the machining program, the smallest amount among the safe amounts can be set as the offset amount. it can. Therefore, the distance between the workpiece and the tool is the smallest distance among the safe distances. Therefore, when the operator checks the operation of the machining program, when the workpiece and the tool are visually checked, it is easy to understand which position of the workpiece the tool cuts.

  In the first embodiment, S3 of the memory operation mode process shown in FIG. 4, that is, the CPU 10 that performs the process of determining the offset amount in the offset amount automatic setting process shown in FIG. 5 corresponds to the “offset amount determining means”. Then, the CPU 10 that repeats the processing of the memory operation mode processing S4 to S7 and operates the numerical controller 1 in consideration of the offset amount determined by the offset amount automatic setting processing of S3 corresponds to “dry run operation means”.

  Next, the “offset amount” in the second embodiment will be described with reference to FIG. FIG. 6 is an explanatory diagram of a method for determining the offset amount. Similar to FIG. 3, the dotted arrow shown in FIG. 6 indicates the movement trajectory of the tip of the tool 2 by the Z-axis movement command, and the solid arrow indicates the movement of the tip of the tool 2 by the Z-axis cutting movement command. The trajectory is shown. In the example shown in FIG. 6, the cutting operation is performed at three locations. The start point of the left cutting movement is SS1 and the end point is SE1, the start point of the center cutting movement is SS2, the end point is SE2, the start point of the right cutting movement is SS3, and the end point is SE3. . The magnitude relationship between the start points is SS2 <SS1 <SS3, and the magnitude relationship between the end points is SE2 <SE1 <SE3. In the present embodiment, the distance between the maximum value of the start point and the minimum value of the end point in the cutting movement in the NC program is defined as an “offset amount”. In the example shown in FIG. 6, the start point SS3 of the right cutting movement is the maximum value of the start point, and the end point SE2 of the center cutting movement is the minimum value of the end point. The distance from the start point SS3 to the end point SE2 is set as an “offset amount”.

  Next, the operation of the numerical controller 1 in the second embodiment will be described with reference to the flowcharts of FIGS. 4 and 7. FIG. 7 is a flowchart of the offset amount automatic setting process performed in the memory operation mode. In the memory operation mode process in the second embodiment, the offset amount automatic setting process is performed when the first start switch 17 is operated after the dry run switch 16 is turned on, as in the first embodiment. The offset amount is automatically set.

  The offset amount automatic setting process will be described with reference to the flowchart of FIG. As shown in FIG. 7, in the offset amount automatic setting process, first, the variable Zmax, the variable Zmin, and the position before movement are initialized, and the first line of the NC program is set as a block to be interpreted (S31). In the pre-movement position, the maximum value of the movement range in the Z-axis direction is stored. In the second embodiment, “600” is set. The initial value of the variable Zmin may be a value that is not less than the maximum value of the movement range of the tool 2 in the Z-axis direction, and the initial value of the variable Zmax may be a value that is not more than the minimum value of the movement range of the tool 2 in the Z-axis direction. In the second embodiment, the minimum value of the movement range of the tool 2 in the Z-axis direction is “0”, the maximum value is “600”, the initial value of the variable Zmax is also “0”, and the initial value of the variable Zmin Is also “600”. These variables are provided with a storage area in the RAM 14.

  Then, the interpretation target block is interpreted (S32). Then, it is determined whether or not this block has a command to move in the Z-axis direction (S33). Here, if there is a Z-axis movement command or a Z-axis cutting movement command in the block being interpreted, it is determined that there is a movement in the Z-axis direction (S33: YES). For example, if “G0Zzz”, “G1Zzz”, “G2Zzz”, “G3Zzz”, “G102Zzz”, “G103Zzz”, “G202Zzz”, “G203Zzz”, the movement is in the Z-axis direction. Note that the lowercase letter z is an arbitrary number, and zzz indicates the coordinate of the movement destination of the Z axis.

  If the movement is in the Z-axis direction (S33: YES), it is further determined whether or not it is a Z-axis cutting movement command (S34). For example, if there are “G1Zzz”, “G2Zzz”, “G3Zzz”, “G102Zzz”, “G103Zzz”, “G202Zzz”, “G203Zzz”, it is determined that the command is a Z-axis cutting movement command (S34: YES). It is determined whether the pre-movement position is higher than the variable Zmax (S35). That is, if the pre-movement position> Zmax, it is determined that it is higher than the variable Zmax (S35: YES), and the value of the pre-movement position is stored in the variable Zmax (S36). If the pre-movement position ≦ Zmax, it is determined that the position is not higher than the variable Zmax (S35: NO), and the variable Zmax is not updated. Next, it is determined whether or not the movement completion position is lower than the variable Zmin (S37). That is, if the coordinate zzz of the movement destination designated by the block being interpreted as the movement completion position <the variable Zmin, the coordinate zzz of the movement destination is stored in the variable Zmin (S38). Further, if the coordinate zzz of the movement destination ≧ variable Zmin, the variable Zmin is not updated. Then, the process proceeds to S39, and the coordinate zzz of the movement destination is stored in the pre-movement position (S39).

  Next, one block to be interpreted is advanced (S41). Then, the process returns to S32 to interpret the block to be interpreted (S32). Then, it is determined whether or not the block moves in the Z-axis direction (S33). If it is a command to move in the Z-axis direction (S33: NO), it is further determined whether or not it is a Z-axis cutting movement command (S34), and if it is not a Z-axis cutting movement command (S34: NO), the coordinates zzz of the movement destination are stored in the pre-movement position (S39). Then, the block to be interpreted is moved to the next line (S41), and the block is interpreted (S32). If there is no command to move in the Z-axis direction in this block (S33: NO), it is determined whether or not it is a program end command (S40). If it is a program end command (S40: YES), the value of “variable Zmax−variable Zmin” is stored in the offset amount (S42), and the process returns to the memory mode operation process.

  In the example of the NC program shown in FIG. 2, since “N1” is “G0Z250” (S33: YES, S34; NO), “250” is stored at the pre-movement position (S39). Next, since “N2” is “M8”, there is no Z-axis movement command (S33: NO) and no program end command (S40: NO), and no variable is updated. Next, since “N3” is “G1Z200” (S33: YES, S34: YES), the pre-movement position is compared with the variable Zmax (S35). At this time, since the position before movement = 250> the variable Zmax = 0 (S35: YES), the variable Zmax is “250” (S36). Since the movement completion position = 200 <600 variable = Zmin (S37: YES), the variable Zmin is “200” (S38). The pre-movement position is set to “200” (S39). Next, since “N4” is “G0Z230” (13: YES, S34; NO), “230” is stored in the pre-movement position (S39). Next, since “N5” is “G1Z198” (S33: YES, S34: YES), the pre-movement position is compared with the variable Zmax (S35). At this time, since the position before movement = 230 <250 = variable Zmax (S35: NO), the variable max is not updated. Since the movement completion position = 198 <200 = variable Zmin (S37: YES), the variable Zmin is “198” (S38). The pre-movement position is “198”. Since “N6” is “M30” (S33: NO), it is determined that the program is finished (S40: YES), and variable Zmax−variable Zmin = 250−198 = “52” is stored in “offset amount” (S42).

  As described above, in the second embodiment, the distance between the maximum value of the start point and the minimum value of the end point in the cutting movement in the NC program is set as the “offset amount”. Therefore, since the offset amount is automatically determined based on the NC program, an offset amount calculation error by the operator, an offset amount input error, and an offset amount may occur when the operator inputs the offset amount. There is no forgetting to input. Therefore, the tool and the work do not come into contact with each other due to human error, and the work is not damaged. In addition, the difference between the position where the tool and the workpiece are farthest in the cutting operation and the position where the tool and the workpiece are closest is the offset amount. Can be set.

  In the second embodiment, S3 of the memory operation mode process shown in FIG. 4, that is, the CPU 10 that performs the process of determining the offset amount in the offset amount automatic setting process shown in FIG. 7 corresponds to the “offset amount determining means”. Then, the CPU 10 that repeats the processing of the memory operation mode processing S4 to S7 and operates the numerical controller 1 in consideration of the offset amount determined by the offset amount automatic setting processing of S3 corresponds to “dry run operation means”.

  Next, a third embodiment will be described with reference to FIGS. FIG. 8 is an explanatory diagram of a method for determining the offset amount. Similarly to FIG. 3, the dotted arrow shown in FIG. 8 indicates the movement locus of the tip of the tool 2 by the Z-axis movement command, and the solid arrow indicates the tip of the tool 2 by the Z-axis cutting movement command. The movement trajectory is shown. In the example shown in FIG. 8, movement and cutting operations are performed at two locations. The start point of the left movement is MS1, the end point of the movement and the start point of the cutting movement are SS1, and the end point is SE2. The start point of the right movement is MS2, the end point of the movement and the start point of the right cutting movement are SS2, and the end point is SE2. In the third embodiment, if there is a Z-axis movement command, the NC program is prefetched, and the movement amount in the Z-axis direction in the next Z-axis cutting movement command is set as the “offset amount”.

  In the example shown in FIG. 8, in the movement from the left start point MS1 to the end point SS1, the cutting movement from the start point SS1 to the end point SE1 is prefetched as the next cutting movement, and the amount of movement of the prefetched cutting movement. (Distance from the start point SS1 to the end point SE1) is set as the “offset amount”. In the cutting movement from the left start point SS1 to the end point SE1, the movement amount of the own cutting movement (the distance from the start point SS1 to the end point SE1) is set as the “offset amount”. Further, in the movement from the right start point MS2 to the end point SS2, the cutting movement from the start point SS2 to the end point SE2 is prefetched as the next cutting movement, and the movement amount of the prefetched cutting movement (from the start point SS2). The distance to the end point SE2) is the “offset amount”. In the cutting movement from the right start point SS2 to the end point SE2, the movement amount of the cutting movement (the distance from the start point SS2 to the end point SE2) is set as the “offset amount”.

  Next, the operation of the numerical control apparatus 1 in the third embodiment will be described with reference to the flowcharts of FIGS. 9 and 10. FIG. 9 is a flowchart of the memory operation mode. FIG. 10 is a flowchart of the offset amount automatic setting process performed in the memory operation mode.

  As shown in FIG. 9, in the memory operation mode process, first, the operation of the start switch 17 is waited. When the start switch 17 is operated, the NC program is read from the RAM 14 and the first block is the block to be interpreted. (S51). Next, the interpretation target block is interpreted (S52). It is determined whether or not the block has a command to move in the Z-axis direction (S53). Here, if there is a Z-axis movement command or a Z-axis cutting movement command in the block being interpreted, it is determined that there is movement in the Z-axis direction (S53: YES). If “G0Zzz”, “G1Zzz”, “G2Zzz”, “G3Zzz”, “G102Zzz”, “G103Zzz”, “G202Zzz”, “G203Zzz”, there is movement in the Z-axis direction. Note that the lowercase letter z is an arbitrary number, and zzz indicates the coordinate of the movement destination of the Z axis. If the command is to move in the Z-axis direction (S53: YES), an offset amount automatic setting process is performed (S54, see FIG. 10). In this offset amount automatic setting process, the offset amount is determined, and details will be described later with reference to FIG. An offset amount is added to the coordinate zzz of the movement destination of the Z axis (S55), and the operation of the block to be interpreted is executed (S57). Then, the block to be interpreted is moved to the next line (S58), and the process returns to S52. If it is not a command to move in the Z-axis direction (S53: NO), it is determined whether or not it is a program end command (S56). If it is not a program end command (S56: NO), the operation of the block to be interpreted is executed (S57), the block to be interpreted is moved to the next line (S58), the process returns to S52, and the steps S52 to S52 are repeated. The process of S58 is performed. If it is an instruction to end the program (S56: YES), the process returns to S51, and the operation of the start switch 17 is waited (S51).

  As described above, every time there is a movement command in the Z-axis direction, the movement distance of the cutting movement after the movement based on the movement command is determined by the offset amount automatic setting process.

  Next, the offset amount automatic setting process will be described with reference to FIG. As shown in FIG. 10, in the offset amount automatic setting process, first, the current Z-axis coordinate position is stored at the position before the command operation, and the block to be interpreted in the offset amount automatic setting process is stored in the memory operation mode process. (S61). A storage area is provided in the RAM 14 for the pre-command operation position and the post-command operation position described later. It is determined whether or not there is a Z-axis cutting movement command in the block being interpreted (S62). If “G1Zzz”, “G2Zzz”, “G3Zzz”, “G102Zzz”, “G103Zzz”, “G202Zzz”, and “G203Zzz” are not present, it is determined that there is no Z-axis cutting movement command (S62: YES). It is determined whether there is a command to move in the direction (S63). Here, if there is a Z-axis movement command or a Z-axis cutting movement command in the block being interpreted, it is determined that there is movement in the Z-axis direction (S63: YES).

  If the movement is in the Z-axis direction (S63: YES), the coordinate zzz of the movement destination of the Z-axis is stored at the pre-command operation position (S65). Next, the block to be interpreted in the offset amount automatic setting process is advanced by one (S66), and the block to be interpreted is interpreted (S67). Then, the process returns to S62, and it is determined whether or not there is a Z-axis cutting movement command in the block being interpreted (S62). If it is a command to move in the Z-axis direction (S62: YES), the coordinate zzz of the movement destination is stored in the pre-movement position in the post-command operation position (S68). Then, the value of “position before command operation−position after command operation” is stored in “offset amount” (S70), and the process returns to the memory mode operation process.

  It should be noted that the blocks following the block that triggered the automatic offset amount setting process have no Z-axis cutting movement command or Z-axis movement command (S62: NO, S63: NO, S64: NO, S66). When the program end command is received (S64: NO), the lowest position of the Z-axis (“0” in the third embodiment) is stored in the post-command operation position (S69). ), The process proceeds to S70, the value of “position before command operation−position after command operation” is stored in the offset amount (S70), and the process returns to the memory mode operation process.

  In the example of the NC program shown in FIG. 2, since “N1” is “G0Z250” (S53: YES), an offset amount automatic setting process is performed (S54). In the offset amount automatic setting process, the uppermost position “600” that is the current position of the Z-axis is stored in the position before the command operation, and the analysis target block “N1” in the memory operation mode process is stored in the offset amount. The block is the analysis target block of the automatic setting process (S61). Since N1 is not a cutting movement (S62: NO) and is a Z-axis movement command (S63: YES), “250” is stored in the pre-command operation position (S65). Next, the Z-axis interpretation target block is “N2” (S67, S67), and “N2” is “M8”, so there is no cutting command (S62: NO), and there is no Z-axis movement command (S63: NO). ) Since it is not a program end command (S64: NO), no variable is updated. Next, in “N3”, since “G1Z200” is a cutting movement command (S62: YES), “200” is stored in the post-command operation position (S68). Then, the pre-command operation position−the post-command operation position = 250−200 = “50” is stored in the “offset amount” (S70). In the memory operation mode process, the offset amount “50” is added to “250” of “G0Z250” of “N1” (S55), and the movement is performed to the position of “300” (S57).

  Then, the next block “N2” is set as a block to be interpreted (S58) and interpreted (S52). Since “N2” is “M8” (S53: NO, S56: NO), cutting oil is supplied (S57), and “N3” is set as a block to be interpreted (S58) and interpreted (S52). Since “N3” is “G1Z200”, it is a command with Z-axis movement (S53: YES), and an offset amount automatic setting process is performed (S54). In the offset amount automatic setting process, the current position “250” of the Z-axis is stored as the pre-command operation position, and the analysis target block “N2” in the memory operation mode process is analyzed in the offset amount automatic setting process. It is set as a target block (S61). Since N3 is a cutting movement (S62: YES), “200” is stored in the post-command operation position (S68). Then, the pre-command operation position−the post-command operation position = 250−200 = “50” is stored in the “offset amount” (S70). In the memory operation mode process, the offset amount “50” is added to “200” of “G1Z200” of “N3” (S55), and cutting is performed to the position of “250” (S57).

  Then, the next block “N4” is set as a block to be interpreted (S58) and interpreted (S52). Since “N4” is “G0Z230”, it is a command with movement of the Z axis (S53: YES), and an offset amount automatic setting process is performed (S54). Then, in the offset amount automatic setting process, the current position “200” of the Z axis is stored in the pre-command operation position, and the analysis target block “N4” in the memory operation mode process is analyzed in the offset amount automatic setting process. It is set as a target block (S61). Since N4 is not a cutting movement (S62: NO) and is a Z-axis movement command (S63: YES), “230” is stored in the pre-command operation position (S65). Next, the Z-axis interpretation target block is “N5” (S66, S67), and “N5” is “G1Z198”, which is a cutting movement (S62: YES). (S68). Then, the pre-command operation position-the post-command operation position = 230-198 = “32” is stored in the “offset amount” (S70). In the memory operation mode process, the offset amount “32” is added to “230” of “G0Z230” of “N4” (S55), and the movement is performed to the position of “262” (S57).

  Then, the next block “N5” is set as a block to be interpreted (S58) and interpreted (S52). Since “N5” is “G1Z198”, it is a command with Z-axis movement (S53: YES), and an offset amount automatic setting process is performed (S54). In the offset amount automatic setting process, the current position “230” of the Z-axis is written at the pre-command operation position, and the analysis target block “N5” in the memory operation mode process is the analysis target of the offset amount automatic setting process. (S61). The block being interpreted is “N5”. Since N5 is a cutting movement (S62: YES), “198” is stored in the post-command operation position (S68). Then, the pre-command operation position-the post-command operation position = 230-198 = “32” is stored in the “offset amount” (S70). In the memory operation mode process, the offset amount “32” is added to “198” of “G1Z198” of “N5” (S55), and cutting is performed to the position of “230” (S57).

  Then, the next block “N6” is set as a block to be interpreted (S58) and interpreted (S52). Since “N6” is “M30”, it is a program end command (S56: YES). Therefore, the process returns to S51 and waits for the start switch 17 to be pressed (S51).

  As described above, in the third embodiment, if there is a Z-axis movement command, the NC program is prefetched, and the movement amount in the Z-axis direction in the next Z-axis cutting movement command is referred to as “offset amount”. To do. Therefore, since the offset amount is automatically determined based on the NC program, an offset amount calculation error by the operator, an offset amount input error, and an offset amount may occur when the operator inputs the offset amount. There is no forgetting to input. Therefore, the tool and the work do not come into contact with each other due to human error, and the work is not damaged. Further, since the offset amount is determined during execution of the machining program, time loss is less than when the entire machining program is analyzed to determine the offset amount.

  In the third embodiment, S54 of the memory operation mode process shown in FIG. 9, that is, the CPU 10 that performs the process of determining the offset amount in the offset amount automatic setting process shown in FIG. 10 corresponds to the “offset amount determining means”. Then, the CPU 10 that repeats the processing of the memory operation mode processing S52 to S58 and operates the numerical controller 1 in consideration of the offset amount determined in the offset amount automatic setting processing of S3 corresponds to “dry run operation means”.

  The numerical control device of the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention. In the first embodiment to the third embodiment, the numerical control device 1 that fixes the workpiece 3 and moves the tool 2 is described as an example. However, both the tool 2 and the workpiece 3 are moved. It may be a numerical control device. Moreover, although the direction in which the tool 2 approaches the workpiece 3 is the Z axis, the direction in which the tool 2 approaches may be another axis.

2 is a block diagram showing an electrical configuration of the numerical control device 1. FIG. It is a schematic diagram of NC program. It is explanatory drawing of the determination method of offset amount. It is a flowchart of a memory operation mode. It is a flowchart of the offset amount automatic setting process performed in the memory operation mode. It is explanatory drawing of the determination method of offset amount. It is a flowchart of the offset amount automatic setting process performed in the memory operation mode. It is explanatory drawing of the determination method of offset amount. It is a flowchart of a memory operation mode. It is a flowchart of the offset amount automatic setting process performed in the memory operation mode.

Explanation of symbols

1 Numerical Control Device 2 Tool 3 Workpiece 10 CPU
16 Dry run switch 17 Start switch 23 Drive circuit 33 Z-axis motor 34 Spindle motor

Claims (6)

A numerical control device for operating a tool held by a spindle and numerically controlling a machine tool that processes a workpiece fixed to a jig based on a processing program,
Dry-run operation means for performing a dry-run operation for operating the tool based on the machining program in a state where the distance between the tool and the workpiece is separated from the distance specified by the machining program by a predetermined offset amount. When,
The movement start position and the movement end position in the cutting instruction of the machining program that moves the tool or the workpiece in a direction in which the tool and the workpiece approach each other and instructs the cutting operation to cut the workpiece by operating the tool. A numerical control device comprising offset amount determining means for determining the offset amount based on   2. The numerical control according to claim 1, wherein the offset amount determination unit determines the largest difference among the differences between the movement start position and the movement end position among the cutting instructions as the offset amount. apparatus.   The offset amount determination means includes a farthest movement start position that is a position in a direction in which the tool and the workpiece are farthest among the movement start positions of the cutting instruction, and the movement end position of the cutting instruction. The numerical control apparatus according to claim 1, wherein the offset amount is determined as a difference between a position where the tool and the workpiece are closest to each other and a latest movement end position. When an instruction to be executed when executing the machining program is the cutting instruction, the machine program includes a next cutting instruction search means for searching the cutting program for the cutting instruction to be executed next to the cutting instruction to be executed,
2. The numerical value according to claim 1, wherein the offset amount determination unit determines a difference between the movement start position and the movement end position of the cutting instruction searched by the next cutting instruction search unit as an offset amount. Control device.   A numerical control program for causing a computer to operate as various processing means of the numerical control device according to any one of claims 1 to 4.   A computer-readable storage medium storing the numerical control program according to claim 5.

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