Patent Publication Number: US-2023158624-A1

Title: Tool measuring system, and control method

Description:
TECHNICAL FIELD 
     The present invention relates to a tool measuring system and a control method. 
     BACKGROUND ART 
     Typically, a numerical control device that controls, e.g., a machine tool executes, e.g., workpiece machining by a machining program (see, e.g., Patent Document 1). A machining program processing device described in Patent Document 1 calculates a correction reference point based on a tool tip point command position and a tool posture command angle commanded by the machining program, and rewrites the tool tip point command position to the position of the correction reference point. 
     Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2019-70953 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     The numerical control device performs not only workpiece machining but also measurement of a tool such as a cutting tool by the machining (control) program. However, for automatically executing measurement of the cutting tool, a macro program using a variable, etc. needs to be created. However, for creating the macro program for measurement, a professional having a skill for programming is required. For this reason, there has been a demand for easy measurement of the cutting tool in the machine tool. 
     Means for Solving the Problems 
     A tool measuring system according to the present disclosure includes a tool measuring instrument that detects an edge of a cutting tool in a machine tool, a tool moving unit that moves the cutting tool to the tool measuring instrument in the machine tool, a tool measuring unit that measures the length and diameter of the cutting tool based on the coordinates of the edge detected by the tool measuring instrument, a tool correcting unit that feeds back the measured length and diameter of the cutting tool to tool length and diameter correction numbers for the cutting tool, and a program computing unit that computes a command executable by the machine tool from a one-line control program for commanding the machine tool to operate the tool measuring instrument, the tool moving unit, the tool measuring unit, and the tool correcting unit. 
     The method for controlling the tool measuring system according to the present disclosure includes the step of computing the command executable by the machine tool from the one-line the control program for commanding the machine tool, the step of detecting the edge of the cutting tool in the machine tool according to the executable command, the step of moving the cutting tool to the tool measuring instrument in the machine tool according to the executable command, the step of measuring, according to the executable command, the length and diameter of the cutting tool based on the coordinates of the edge detected by the tool measuring instrument, and the step of feeding back the measured length and diameter of the cutting tool to the tool length and diameter correction numbers for the cutting tool according to the executable command. 
     Effects of the Invention 
     According to the present invention, the cutting tool can be easily measured. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram showing the configuration of a tool measuring system; 
         FIG.  2    is a view showing the outline of a machine tool; 
         FIG.  3    is a view showing a specific example of a control program; and 
         FIG.  4    is a flowchart showing the processing of the tool measuring system. 
     
    
    
     PREFERRED MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, an embodiment of the present invention will be described as one example.  FIG.  1    is a diagram showing the configuration of a tool measuring system  1 . As shown in  FIG.  1   , the tool measuring system  1  includes a numerical control device  2  and a machine tool  3 . 
     The numerical control device  2  is a device that controls the machine tool  3  to perform, e.g., predetermined machining. The numerical control device  2  includes a control unit  21 . The control unit  21  is a processor such as a central processing unit (CPU), and functions as a tool moving unit  211 , a tool measuring unit  212 , a tool correcting unit  213 , and a program computing unit  214  by executing programs stored in a storage unit (not shown). 
     The machine tool  3  is a device that performs the predetermined machining such as cutting, tool measurement, etc. based on control by the numerical control device  2 .  FIG.  2    is a view showing the outline of the machine tool  3 . 
     The machine tool  3  includes, for example, a motor driven to machine a workpiece  41 , a spindle and a feed shaft attached to the motor, a jig and a tool for each of these shafts, and a table  42  for fixing the workpiece  41 . The machine tool  3  drives the motor based on an operation command output from the numerical control device  2 , thereby performing the predetermined machining. Specifically, the machine tool  3  includes a cutting tool  31  and a tool measuring instrument  32 . 
     Next, operation of the tool measuring system  1  will be described. Plural types of cutting tools  31  are prepared according to a purpose for machining. Each cutting tool  31  is replaced with attached to a dedicated tool holder. A specific tool number is assigned to each cutting tool  31 . 
     The tool measuring instrument  32  is a contact or contactless measuring instrument. For example, the contact tool measuring instrument  32  detects an edge of the cutting tool  31  according to contact of the cutting tool  31  with, e.g., a detection switch, a probe, or a plunger. For example, the contactless tool measuring instrument  32  detects the edge of the cutting tool  31  by means of, e.g., a laser beam and a laser beam light receiving unit. 
     The tool moving unit  211  moves the cutting tool  31  to the tool measuring instrument  32  in the machine tool  3 . Specifically, the machine tool  3  moves the cutting tool  31  in the horizontal direction (an X-axis direction and a Y-axis direction) and the vertical direction (a Z-axis direction) by the motor and a drive shaft, thereby moving the cutting tool  31  to the tool measuring instrument  32 . 
     The tool measuring unit  212  calculates the length and diameter of the cutting tool  31  based on the coordinates of the detected edge of the cutting tool  31 . 
     The tool correcting unit  213  feeds hack the measured length and diameter of the cutting tool  31  to tool length and diameter correction numbers for the cutting tool  31 . Thus, the tool measuring system  1  can correct the length and diameter values of the cutting tool  31  according to the measured length and diameter of the cutting tool  31 . 
     The program computing unit  214  computes a command executable by the machine tool  3  from a one-line control program for commanding the machine tool  3  to operate the tool measuring instrument  32 , the tool moving unit  211 , the tool measuring unit  212 , and the tool correcting unit  213 . 
     Specifically, the control program includes a G-code, a measurement mode, a tool start number, a tool end number, the tool length and diameter correction numbers, a temporal tool length, X-direction positioning, Y-direction positioning, Z-direction positioning, a spindle phase, and a first feed speed. 
     The G-code described herein indicates the function of measuring the cutting tool  31  by means of the one-line control program in the machine tool  3 . The measurement mode indicates a mode for measuring the cutting tool  31 . The tool start number and the tool end number each indicate the number of the cutting tool  31  for which measurement is started and the number of the cutting tool  31  for which measurement is finished. 
     The tool length correction number is a number for correcting the tool length according to a specified number, and the machine tool  3  corrects the tool length according to the specified number. The tool diameter correction number is a number for correcting the tool diameter according to a specified number, and the machine tool  3  corrects the tool diameter according to the specified number. The temporal tool length is a temporal tool length before measurement of the cutting tool  31 . 
     The X-direction positioning, the Y-direction positioning, and the Z-direction positioning each indicate positioning in the linear X-, Y-, and Z-axis (the axes of coordinates) directions. The spindle phase is the rotation angle position of a spindle, and the machine tool  3  rotates the cutting tool  31  to a measurement target blade based on the spindle phase. The first feed speed indicates the feed speed of the cutting tool  31  from the origin of each linear axis (the X-axis, the Y-axis, and the Z-axis). 
       FIG.  3    is a view showing a specific example of the control program. In the example shown in  FIG.  3   , the G-code is G910, and S, T, E, H, D, B, X, Y, C, F, and M are used as parameters. G910 is a G-code for measuring the cutting tool  31  according to the one-line control program in the machine tool  3 . 
     The parameter S indicates the measurement mode, the parameter H indicate the tool length and diameter correction numbers for the cutting tool  31 , and the parameter D indicates tool length and diameter correction start numbers for the cutting tool  31 . Note that the parameters S and H are essential values. 
     The parameters T, E, B, X, Y, C, F, and M each indicate the tool start number, the tool end number, the temporal tool length, the X-direction positioning, the Y-direction positioning, the spindle phase, the first feed speed, and a program stop before measurement. Note that the parameters T, E, B, X, Y, C, F, and M are optional values. 
     The program computing unit  214  specifies, for measuring the length and diameter of the cutting tool  31 , the feed speed of the cutting tool  31  from the origin of each linear axis (the X-axis, the Y-axis, and the Z-axis) of the machine tool  3  in the control program. Specifically, the program computing unit  214  specifies the value of the parameter F in the control program, thereby specifying the feed speed of the cutting tool  31  from the origin of each linear axis of the machine tool  3 . 
     Moreover, the program computing unit  214  specifies, for measuring the cutting tool  31  after replacement thereof, the tool number of the cutting tool  31  in the control program when measurement of the cutting tool  31  is commanded. Specifically, the program computing unit  214  specifies the parameter T as the tool start number in the control program, thereby specifying the tool number of the cutting tool  31 . 
     Further, the program computing unit  214  specifies all of the cutting tools  31  or a predetermined tool number range in the control program when measurement of the cutting tool  31  is commanded. Specifically, the program computing unit  214  specifies the parameter T as the tool start number and the parameter E as the tool end number in the control program, thereby specifying all of the cutting tool  31  or the predetermined tool number range. 
     In addition, the program computing unit  214  specifies, for measuring an optional height on a plane perpendicular to the cutting tool  31 , at least one linear axis perpendicular to the axis along which the cutting tool  31  is held, in the control program when measurement of the cutting tool  31  is commanded. Specifically, the program computing unit  214  specifies at least one linear axis (at least one of the X-axis or the Y-axis) perpendicular to the axis (the Z-axis) along which the cutting tool  31  is held, in the control program. With this configuration, the tool measuring system  1  can measure a tool having a trapezoidal shape, for example. 
       FIG.  4    is a flowchart showing the processing of the tool measuring system  1 . In Step S 101 , the program computing unit  214  reads the machining program from the storage unit (not shown). 
     In Step S 102 , the program computing unit  214  determines whether or not the machining program includes the tool start number T. In a case where the machining program includes the tool start number T (YES), the processing proceeds to Step S 103 . In a case where the machining program does not include the tool start number T (NO), the processing proceeds to Step S 104 . 
     In Step S 103 , the numerical control device  2  causes the machine tool  3  to replace the cutting tool  31 . In Step S 104 , the program computing unit  214  determines whether the measurement mode is S 1  or S 2  in the machining program. In a case where the measurement mode is S 1 , the processing proceeds to Step S 105 . In a case where the measurement mode is S 2 , the processing proceeds to Step S 109 . 
     In Step S 105 , the program computing unit  214  determines whether or not the machining program includes the temporal tool length B command. In a case where the temporal tool length B command is included (YES), the processing proceeds to Step S 106 . In a case where the temporal tool length B command is not included (NO), the processing proceeds to Step S 107 . 
     In Step S 106 , according to the temporal tool length, the numerical control device  2  fast-forwards the cutting tool  31  to the tool measuring instrument  32  and sets the position of the cutting tool  31  at the tool measuring instrument  32 . Then, the numerical control device  2  performs measurement from the set position. With this configuration, the numerical control device  2  can move the cutting tool  31  to a position immediately before a measurement position of the tool measuring instrument  32  by fast-forwarding. 
     In Step S 107 , the numerical control device  2  moves the cutting tool  31  to the tool measuring instrument  32  at the feed speed F, and performs measurement at such a feed speed. With this configuration, the numerical control device  2  can easily perform measurement from the Z-axis without the temporal tool length. 
     In Step S 108 , the tool measuring instrument  32  feeds back a measurement value to the numerical control device  2  according to the commands of the parameters H and D. At this point, the numerical control device  2  sets, in measurement operation, the position of the cutting tool  31  at the tool measuring instrument  32  according to the commands of the parameters X and Y. Moreover, the numerical control device  2  sets the spindle phase for measuring, e.g., an edge of a cutting tool for milling according to the command of the parameter C. 
     In Step S 109 , the numerical control device  2  sets the position of the cutting tool  31  at the tool measuring instrument  32  according to a correction value of the tool length correction number. 
     In Step S 110 , the tool measuring instrument  32  executes measurement of abrasion of the cutting tool  31 . Then, the tool measuring instrument  32  determines whether or not an abrasion value of the cutting tool  31  exceeds an acceptable abrasion detection value. In a case where the abrasion value exceeds the acceptable abrasion detection value (YES), the processing proceeds to Step S 111 . In a case where the abrasion value is equal to or less than the acceptable abrasion detection value (NO), the tool measuring instrument  32  ends abrasion measurement, and then, the processing ends. 
     In Step S 111 , the machine tool  3  issues an alarm for informing the abrasion value exceeding the acceptable abrasion detection value, and thereafter, the processing ends. 
     As described above, according to the present embodiment, the tool measuring system  1  includes the tool measuring instrument  32  that detects the edge of the cutting tool  31  in the machine tool  31 , the tool moving unit  211  that moves the cutting tool  31  to the tool measuring instrument  32  in the machine tool  3 , the tool measuring unit  212  that measures the length and diameter of the cutting tool  31  based on the coordinates of the edge detected by the tool measuring instrument  32 , the tool correcting unit  213  that feeds back the measured length and diameter of the cutting tool  31  to tool length and diameter correction numbers for the cutting tool  31 , and the program computing unit  214  that computes a command executable by the machine tool  3  from the one-line control program for commanding the machine tool  3  to operate the tool measuring instrument  32 , the tool moving unit  211 , the tool measuring unit  212 , and the tool correcting unit  213 . 
     Typically, a worker needs to create, as the technique of measuring a cutting tool in a machine tool  3 , a macro program having branches according to various measurement specifications, and also needs to have a skill for programming. A worker unfamiliar with programming cannot create an optimal program, leading to the probability of damaging a measuring instrument due to operation of an erroneous program. The tool measuring system  1  according to the present embodiment creates the one-line control program for commanding the machine tool  3  to operate the tool measuring instrument  32 , the tool moving unit  211 , the tool measuring unit  212 , and the tool correcting unit  213 . With this configuration, the tool measuring system  1  can easily measure the cutting tool by the one-line control program. 
     The control program includes the G-code, the measurement mode, the tool start number, the tool end number, the tool length and diameter correction numbers, the temporal tool length, the X-direction positioning, the Y-direction positioning, the Z-direction positioning, the spindle phase, and the first feed speed. With this configuration, the tool measuring system  1  can measure the cutting tool  31  by the control program by proper operation of the machine tool  3  and the numerical control device  2 . 
     The program computing unit  214  specifies, for measuring the length and diameter of the cutting tool  31 , the feed speed of the cutting tool  31  from the origin of each linear axis (the X-axis, the Y-axis, and the Z-axis) of the machine tool  3  in the control program. With this configuration, the tool measuring system  1  can suitably measure the length and diameter of the cutting tool  31 . 
     The program computing unit  214  specifies, for measuring the cutting tool  31  after replacement thereof, the tool number of the cutting tool  31  in the control program when measurement of the cutting tool  31  is commanded. With this configuration, the tool measuring system  1  can measure the cutting tool  31  after replacement thereof. 
     The program computing unit  214  specifies all of the cutting tools or the predetermined tool number range in the control program when measurement of the cutting tool  31  is commanded. With this configuration, the tool measuring system  1  can properly specify the tool number of the cutting tool  31 . 
     The program computing unit  214  specifies, for measuring the optional height on the plane perpendicular to the cutting tool  31 , at least one linear axis perpendicular to the axis along which the cutting tool  31  held, in the control program when measurement of the cutting tool  31  is commanded. The tool measuring system  1  can measure the tool having the trapezoidal shape, for example. 
     The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment. The advantageous effects described in the present embodiment have merely been listed as most suitable advantageous effects of the present invention, and the advantageous effects of the present invention are not limited to those described in the present embodiment. 
     EXPLANATION OF REFERENCE NUMERALS 
       1  Tool Measuring System 
       2  Numerical Control Device 
       3  Machine Tool 
       21  Control Unit 
       31  Cutting Tool 
       32  Tool Measuring Instrument 
       211  Tool Moving Unit 
       212  Tool Measuring Unit 
       213  Tool Correcting Unit 
       214  Program Computing Unit