JP2010167516A - Numerical control device of five-axis machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a numerical control device for controlling a five-axis machine tool which finds an optimum permissible correction amount. <P>SOLUTION: The drawing is a schematic diagram of a display device 70 with an input device included in the numerical control device. A keyboard 73 includes number keys, alphabet keys and the like. A prompt area 74 is displayed for inputting a cumulative relative frequency (%) on a display screen 71. An instruction by which an operator sets what percent of a tool direction command is desired to be sufficiently corrected is assigned to "F5" of function keys 72. A value inputted using the number key of the keyboard 73 is displayed on the prompt area 74, and the value is set by pressing the "F5". An instruction for outputting frequency distribution data to an external device (not shown) is assigned to "F6" of the function keys 72, and the frequency distribution data are transmitted to the external device by pressing the "F6". <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a numerical controller for a 5-axis machine.

  There is known a 5-axis processing machine that processes a workpiece mounted on a table by three linear axes and two rotation axes. A 5-axis processing machine is a numerical control device for a machine tool having one axis for table rotation and one axis for tool head rotation, two axes for tool head rotation, or two axes for table rotation. While the rotary shaft rotates, the tool tip can move along the intended path at the desired speed to machine the workpiece.

Japanese Patent Laid-Open No. 2003-195917

In a numerical control device for controlling a 5-axis machining apparatus, a numerical control device that corrects a tool direction command so that a change amount of a tool direction and a change amount of a linear movement axis are proportional to a program command ( Hereinafter, the present applicant has filed an application as Japanese Patent Application No. 2007-322546.
The numerical controller A calculates the optimum tool direction in each block of the machining program. Here, if this optimal tool direction is used as the corrected tool direction, if there is a large difference from the original tool direction before correction, even if the tool does not interfere with the machine or workpiece in the original tool direction, interference will occur. May occur.

  For this reason, the numerical controller A calculates a sub-optimal tool direction that falls within the range of the allowable correction amount specified from the original tool direction on the basis of the optimal tool direction, and corrects the sub-optimal tool direction. It is necessary to use it as the tool direction. At this time, when the allowable correction amount is small, the corrected tool direction is not changed from the original tool direction, so that the effect of shortening the machining time and the effect of improving the machined surface quality due to the correction are reduced.

  As the allowable correction amount is larger, the corrected tool direction approaches the optimum tool direction, so that the effect of reducing the machining time and the effect of improving the machined surface quality are enhanced. Therefore, it is desirable that the allowable correction amount is set to a large value, but at the same time, it is necessary to avoid interference of the tool with the machine or workpiece, so that the corrected tool direction must be sufficiently close to the optimum tool direction. It is desirable to keep it in a large size.

However, since the numerical controller A cannot determine how much the allowable correction amount is set when the sub-optimal tool direction is determined, the corrected tool direction is sufficiently close to the optimal tool direction. The person has to set a value depending on experience and intuition, or to process the workpiece many times while changing the allowable correction amount and find the optimum allowable correction amount.
SUMMARY OF THE INVENTION An object of the present invention is to provide a numerical control device for controlling a 5-axis machine that can solve the above-described problems and find an optimum allowable correction amount.

  The invention according to claim 1 of the present application controls a five-axis processing machine configured by three linear axes and two rotary axes for processing a workpiece attached to a table, and a movement path of the linear axes. A command reading means for reading the command, a relative movement speed command between the workpiece and the tool, and a tool direction command as a tool direction with respect to the table; and calculating an optimum tool direction from the tool direction command, and calculating the tool direction command and the calculation The sub-optimal tool direction is calculated so that the difference in the optimum tool direction obtained in this way is within a preset allowable range, and the sub-optimal tool direction is set as the tool direction of the tool direction command. Tool direction command correcting means for correcting the tool direction command, and the tool tip point is commanded and moved based on the tool direction command corrected by the tool direction command correcting means, the movement path command, and the relative movement speed command. Interpolating means for obtaining the position of each axis for each interpolation cycle so as to move at the commanded relative movement speed, and means for driving each axis motor to move to each axis position obtained by the interpolating means 5 In the numerical control device of the shaft machine, ideal correction amount calculating means for calculating an ideal correction amount that is a difference between the tool direction command and an optimum tool direction calculated by the tool direction command correcting means, and the ideal correction amount An ideal correction amount storage unit that stores the ideal correction amount calculated by the calculation unit, and the ideal correction amount stored in the ideal correction amount storage unit are output as a frequency distribution of the tool direction command for each predetermined correction amount. And a numerical control device for a five-axis machine.

According to a second aspect of the present invention, the output means is provided in the numerical controller that displays the ideal correction amount stored in the ideal correction amount storage means as a frequency distribution of the tool direction command for each predetermined correction amount. 2. The numerical control device for a 5-axis machining apparatus according to claim 1, wherein the numerical control device is a display device or a display device of an external device connected to the numerical control device.
According to a third aspect of the present invention, there is provided an accumulating unit for accumulating the number of tool direction commands, a ratio designating unit for designating a ratio with respect to the number of tool direction commands, and a small value of an ideal correction amount of the tool direction commands in order. Cumulative frequency distribution acquisition means for accumulating the number of tool direction commands to obtain a cumulative frequency distribution, and the accumulated number of tool direction commands coincides with the number of tool direction commands corresponding to the ratio specified by the ratio specifying means. An acquisition unit that acquires an ideal correction amount of a tool direction command when the tool direction command is performed, and a setting unit that sets the ideal correction amount acquired by the acquisition unit as the preset allowable range. The numerical control device for a 5-axis machining apparatus according to any one of 1 and 2.

According to a fourth aspect of the present invention, the numerical control device includes: an actual correction amount calculating unit that calculates an actual correction amount when the tool direction command is corrected to the semi-optimal tool direction;
Actual correction amount storage means for storing the actual correction amount calculated by the actual correction amount calculation means, and the actual correction amount stored in the actual correction amount storage means for each predetermined correction amount. The numerical control device for a 5-axis machining apparatus according to any one of claims 1 to 3, wherein the numerical value is output to the output means as a frequency distribution of a tool direction command.
The invention according to claim 5 is a statistic calculation means for calculating a statistic based on a frequency distribution of the tool direction command for each of the ideal correction amount and the actual correction amount;
5. The numerical control device for a 5-axis machining apparatus according to claim 4, wherein the statistical quantity calculated by the statistical quantity calculation means is output to the output means.

  According to the present invention, it is possible to provide a numerical control device for controlling a 5-axis machine capable of finding an optimum allowable correction amount.

It is a figure which shows a process curved surface. It is a figure which shows dividing | segmenting a process curved surface in the division called a triangular patch. It is a figure which shows calculating a tool locus on a triangular patch. It is a figure which shows the relationship between a triangular patch, a tool course, and a tool front-end | tip point position. It is a figure which shows sectional drawing along the tool path of a triangular patch. The position commands P1 to P10 for the X, Y and Z axes are represented by X, Y and Z axes, the position commands Pb1 to Pb10 for the B axis and the position commands Pc1 to Pc10 for the C axis are represented by one-dimensional coordinates, respectively. It is a figure showing the contrast of these. It is a figure which shows an example of the velocity waveform of each axis | shaft in case the ratio of each rotation axis movement amount and linear axis movement amount in each block is not constant. FIG. 7 is a diagram when the rotation axis position command is corrected for the B axis and C axis position commands shown in FIG. 6. It is a figure which shows an example of the velocity waveform of each axis | shaft at the time of correcting a rotating shaft position command. It is explanatory drawing of a 5-axis processing machine of a tool head rotation type. It is a general | schematic functional block diagram of the numerical control apparatus which controls a 5-axis processing machine. It is an example of the flowchart which shows the algorithm which performs tool direction command correction | amendment. It is a principal part block diagram of the numerical control apparatus which performs embodiment of this invention. It is a figure explaining the frequency distribution table of the ideal correction amount in the present invention. The function key is pressed to output the frequency distribution data of the ideal correction amount to the external device, and the user inputs what percentage of the entire command is to be corrected sufficiently, and the numerical control device sets the optimum allowable correction amount accordingly. It is a figure explaining setting automatically. It is a figure explaining 0.2 degree being automatically set as an allowable correction amount. It is a graph which shows cumulative frequency distribution. It is a graph which shows cumulative relative frequency distribution. It is a flowchart which shows the algorithm of the process which updates the frequency distribution of a correction amount, and recalculates the statistic of a frequency distribution whenever the block is corrected each time (the 1). It is a flowchart which shows the algorithm of the process which updates the frequency distribution of a correction amount, and recalculates the statistic of a frequency distribution whenever the block is corrected each time (the 2). FIG. 10 is a flowchart showing an algorithm of a process in which a correction amount frequency distribution is updated until a designated m block is read, a frequency distribution statistic is calculated when the designated m block is read, and thereafter the frequency distribution is not updated. Part 1). FIG. 10 is a flowchart showing an algorithm of a process in which a correction amount frequency distribution is updated until a designated m block is read, a frequency distribution statistic is calculated when the designated m block is read, and thereafter the frequency distribution is not updated. 2). It is a flowchart which shows the algorithm of the process which calculates the statistics of frequency distribution at the time of completion | finish of a program (the 1). It is a flowchart which shows the algorithm of the process which calculates the statistics of frequency distribution at the time of completion | finish of a program (the 2).

A method for finding the optimum allowable correction amount in the present invention will be described. First, the numerical controller A disclosed in the specification attached to the application of Japanese Patent Application No. 2007-322546 (hereinafter referred to as “prior application”), which is the previous application, will be described.
An object of the prior application is to provide a numerical control device for controlling a 5-axis machining machine capable of smoothing a machining shape and shortening a machining time by correcting a tool direction command itself.

  The invention according to claim 1 of the prior application is a numerical control device for controlling a 5-axis processing machine constituted by three linear axes and two rotary axes for processing a workpiece attached to a table. A command reading means for reading a tool path command as a moving path command for the linear axis, a relative moving speed command between the workpiece and the tool, and a tool direction with respect to the table; a tool direction command correcting means for correcting the tool direction command; Based on the tool direction command corrected by the tool direction command correcting means, the movement path command, and the relative movement speed command, the tool tip point is interpolated so as to move at the commanded relative movement speed on the commanded movement path. A numerical control device having interpolation means for obtaining each axis position for each period and means for driving each axis motor to move to each axis position obtained by the interpolation means

In the invention according to claim 2 of the prior application, the tool direction command correction means corrects the tool direction command so that the change amount of the tool direction is proportional to the change amount of the linear axis in the movement path command. The numerical control device according to claim 1.
The invention according to claim 3 of the prior application is characterized in that the tool direction command is commanded by the position of the two rotary shafts, and the tool direction command correcting means corrects the commanded position of the two rotary shafts. It is a numerical control apparatus as described in any one of Claim 1 or 2.
The invention according to claim 4 of the prior application is characterized in that the tool direction command is commanded as a tool direction vector, and the tool direction command correction means corrects the commanded tool direction vector. It is a numerical control apparatus as described in any one.
In the invention according to claim 5 of the prior application, the tool direction command correcting means converts the commanded tool direction vector into the position of the two rotation axes, corrects the converted position of the two rotation axes, and corrects the rotation. The numerical control device according to claim 4, wherein the position of the two axes is inversely converted into a tool direction vector.

In the invention according to Claim 6 of the prior application, when the command reading means is instructed in the tool direction command correction mode, a preset number of blocks are corrected until the tool direction command correction mode is instructed. The numerical control apparatus according to claim 1, wherein the tool direction command correcting unit corrects the tool direction command in the correction target program command.
The invention according to claim 7 of the prior application is characterized in that the tool direction command correction mode is commanded by a G code, and the tool direction command correction mode cancellation is commanded by a G code different from the G code. 6. The numerical control device according to 6.
The effect of the prior invention is that when a workpiece is machined using a five-axis machine, the machining time can be shortened while the machining shape of the workpiece is smoothed.

  The invention of the prior application corrects the tool direction command itself commanded at the block end point, thereby reducing the machining time while smoothing the machining shape of the workpiece. In general, when machining a workpiece using a 5-axis machine, it is important to move the tool tip to machine the workpiece, but even if there is some error in the tool direction, it has a significant effect on machining. Not give. On the other hand, the fact that the machining shape is not smooth and that the machining time is long are problems to be solved in a 5-axis machine. Therefore, in the prior invention, the tool direction command is corrected so that the machining shape of the workpiece can be made smooth and the machining time can be shortened by allowing an error in the tool direction. Hereinafter, a first embodiment and a second embodiment for correcting the tool direction command of the invention of the prior application will be described.

  A first embodiment of the invention of the prior application will be described using a program command example 1 shown in Table 1. This program command is generated by the CAM described in the section of the problem to be solved by the invention. The technology itself for generating the program command is a known technology.

  When the tool direction command correction mode is entered, until the tool direction command correction mode is cancelled, blocks corresponding to the maximum number of prefetched blocks are prefetched as correction target program commands. The tool direction command is corrected so that the ratio of the movement amount and the linear axis movement amount is constant. Note that the maximum number of prefetch blocks is set as a separate parameter.

  Here, Gaa is a G code for instructing the tool direction command correction mode, and Gbb is a G code for instructing the tool direction command correction mode to be canceled. The relative movement speed f between the workpiece and the tool in the movement path of the tool tip point commanded by X, Y, and Z has already been commanded as a modal command Ff before Gaa is commanded.

  Assume that the X, Y, and Z axis position commands of each block and the B and C axis position commands are as shown in FIG. In FIG. 6, position commands P1 (Px1, Py1, Pz1) to P10 (Px10, Py10, Pz10) for the X, Y, and Z axes are represented by X, Y, and Z coordinates, and position commands Pb1 to Pb10 for the B axis and The position commands Pc1 to Pc10 for the C axis are each represented by one-dimensional coordinates, and their comparison is represented. P0 (Px0, Py0, Pz0), Pb0, and Pc0 represent the positions of the respective axes at the time of Gaa command.

  Therefore, while the X, Y, and Z axes move at a speed f between P0 (Px0, Py1, Pz1) to P10 (Px10, Py10, Pz10), the B axis is Pb0 to Pb10, and the C axis is Pc0 to Pc10. Move between. In each block, while the X, Y, and Z axes move at a speed f between P0 (Px0, Py0, Pz0) and P1 (Px1, Py1, Pz1), the B axis is Pb0 to Pb1, and the C axis is Pc0. ~ Pc1, while the X, Y, and Z axes move at a speed f between P1 (Px1, Py1, Pz1) and P2 (Px2, Py2, Pz2), the B axis is Pb1 to Pb2, and the C axis is Pc1 The X, Y, and Z axes and the B and C axes move in synchronization with each block, such as moving between .about.Pc2.

  The range between Gaa and Gbb shown in Table 1 is an example of a command of 10 blocks, but the number of blocks is not limited. Each axis position command is an absolute command. The two rotation axes are represented by B and C axes, but the same applies to the names of other axes, for example, the A and B axes and the A and C axes.

  Here, the ratio of each rotational axis movement amount and linear axis movement amount in each block is not constant. In other words, when the ratio of each rotational axis movement amount to the linear axis movement amount is calculated from 0 to 9 in Equation 1 and Equation 2, the ratio of each rotational axis movement amount to the linear axis movement in each block is calculated. Is not constant.

  FIG. 7 shows an example of the velocity waveform of each axis at this time. In FIG. 7, the horizontal axis represents time, and the vertical axis represents the speed of each axis. In the figure, 35000 represents milliseconds. The unit of speed of each axis (for example, mm / min, degree / min) is different for each axis, but in FIG. FIG. 7 shows that the speed of each axis vibrates. Each wave of this vibration corresponds to each block command. FIG. 7 shows an example of the velocity waveform of each axis when the number of command blocks is not about 10 but about 500.

Therefore, Pb1 to Pb10 and Pc1 to Pc10 are set as follows so that the ratio of the rotational axis movement amount and the linear axis movement amount in each block calculated by Equation 1 and Equation 2 is constant. to correct. When the numerical controller reads Gaa, it starts prefetching and correction processing. The maximum number of prefetch blocks is 5.
Here, the following mathematical formula will be described. Equation 3 and Equation 4 are transitional equations from the beginning to Equation 5, and Equations 6 and 7 are transient equations from Equation 5 to the end, so Equation 5 is important. It is.
Therefore, Formula 5 will be described in detail. In Equation 5, the linear axis movement amount in the look-ahead block (from the (n−2) th block to the (n + 2) th block) is calculated using the denominator on the right side. In the right side numerator, the linear axis movement amount of the correction target block (the nth block) is calculated. Therefore, the term of the right-hand side fraction is a ratio between the linear axis movement amount in the look-ahead block and the linear axis movement amount in the correction target block.
Then, by multiplying the ratio by the amount of movement (Pα _{n + 2} −Pα _n−3 ′) of the rotation axis (B axis or C axis) of the prefetch block (from the (n−2) th block to the (n + n) th block), The correction is performed so that the ratio between the rotational axis movement amount and the linear axis movement amount of the correction target block is constant within the range.
The correction target block is obtained by adding the corrected rotation axis movement amount to the block immediately before the correction target block (the (n−1) th block), that is, the already corrected rotation axis position command (Pα _n−1 ′). The rotation axis position command at is obtained. This is a corrected rotation axis position command based on the corrected rotation axis movement amount.
(A) The first block is read, and the first block is not corrected as shown in Equation 3.

(B) The second and third blocks are read, and the B-axis and C-axis position commands of the second block are corrected as shown in Formula 4.

(C) The (n + 1) th and (n + 2) th blocks are read, and the B-axis and C-axis position commands of the nth block are corrected as shown in Equation 5 (n = 3 to 8). However, when n = 4 to 8, the (n + 1) th block has already been read.

(D) Read Gbb and stop reading new block. As shown in Equation 6, the position commands for the B-axis and C-axis of the ninth block are corrected.

(E) The 10th block is not corrected.

  As described in (A) to (E) above, the rotation axis position command is corrected while sequentially prefetching the blocks. The B-axis and C-axis position commands shown in FIG. 6 are expressed in FIG. 8 by correcting the rotation axis position command using the equations (3) to (7). Instead of correcting after reading all the blocks, the B-axis and C-axis movement amounts of each block can be corrected so as to be substantially proportional to the corresponding linear axis movement amounts.

  When the rotation axis position command described in the above (A) to (E) is corrected, the ratio of each rotation axis movement amount to each linear axis movement amount in each block shown in FIG. The velocity waveform is as shown in FIG. As shown in FIG. 9, the vibration of the speed of each axis in each block is suppressed by correcting the rotation axis position command. By suppressing the vibration of speed, the processed shape of the workpiece becomes smooth. In addition, the machining time is shortened by reducing the number of parts that decelerate. In the example shown in FIG. 9, the machining time is reduced to about 70% compared to the case where the rotation axis position command is not corrected. In addition, power consumption for processing operations can be reduced.

  An interpolation cycle is performed so that the tool tip point moves on the commanded movement path based on the tool direction command, the movement path command, and the relative movement speed command corrected by the tool direction command correcting means. A known technique can be used for the interpolation means for obtaining each axis position and the means for driving each axis motor to each axis position obtained by the interpolation means as in the numerical control device shown in FIG. . The numerical controller of FIG. 13 will be described later.

  A second embodiment of the invention of the prior application will be described using a program command example 2 shown in Table 2. The prefetching method and the like are the same as those in the first embodiment.

  In the second embodiment, the tool direction is commanded as a tool direction vector with I, J, and K normalized. As described above, the technique of instructing the tool direction as the tool direction vector is a known technique in Patent Document 1 described in the background art. The tool direction vector is calculated from the position information of the axis that controls the tilt of the tool. For example, when the tilt of the tool is controlled by the B axis and the C axis, the tool direction vector is calculated from the current positions of the B axis and the C axis.

  As shown in FIG. 10, if the machine configuration is a rotary head type 5-axis machine, the B and C axis positions can be calculated from the following equations (8) and (9) from the I, J, and K commands. it can. Here, Pcn is set to 0 degrees to 360 degrees, and Pbn is set to 0 degrees to 90 degrees. Note that n = 1 to 10.

  As a result, the tool direction vector command (Pin, Pjn, Pkn) by I, J, K of each block is converted into the B, C axis position (Pbn, Pcn). As in the first embodiment, the rotational axis position is corrected while sequentially performing prefetching, and the corrected B and C axis positions (Pbn ′, Pcn ′) can be obtained.

As a result, the B and C axis movement amounts of each block are corrected so as to be substantially proportional to the corresponding linear axis movement amounts. The corrected B and C axis positions (Pbn ′, Pcn ′) are inversely converted into tool direction vector commands (Pin ′, Pjn ′, Pkn ′) by I, J, K again by solving the simultaneous equations of Formula 9. can do. As a result, it can be executed as a program command by the original X, Y, Z, I, J, K.
Here, as shown in FIG. 10, a tool rotating head type five-axis processing machine has been described. However, a five-axis processing machine includes a table rotating type five-axis processing machine that rotates a table with two rotation axes, and a rotation. There is also a mixed 5-axis machine that rotates the tool head on one axis and the table on the other axis. In these five-axis machines, the tool direction according to the commands I, J, and K is converted into the position of the two rotation axes, the converted position of the two rotation axes is corrected, and the corrected position of the two rotation axes is changed again. It is possible to reversely convert into I, J, and K commands. The conversion and inverse conversion methods are different from each other only in the function forms of the equations (8) and (9).

  FIG. 11 is a schematic functional block diagram of a numerical controller for controlling the 5-axis machining apparatus of the prior invention. The command reading means 1 reads the program command of each block. The read program command is corrected by the tool direction command correcting means 2 so that the ratio of the rotational axis movement amount and the linear axis movement amount in each block becomes constant. The interpolating means 3 moves the tool tip point at the commanded speed on the commanded movement path based on the tool direction command, the movement path command and the relative movement speed command corrected by the tool direction command correcting means 2. Interpolation calculation for obtaining the position of each axis is executed for each interpolation cycle. Each axis servo 4X, 4Y, 4Z, 4B (A), 4C axis servo drives each axis motor (each axis motor is omitted) to each axis position calculated by the interpolation means 3.

FIG. 12 is an example of a flowchart showing an algorithm for executing the tool direction command correction shown in the first embodiment of the prior invention. This flowchart shows processing after reading Gaa in Table 1. It is assumed that at least 5 blocks are commanded between Gaa and Gbb. Hereinafter, it demonstrates according to each step.
[Step S1] n is set to 1. [Step S2] It is determined whether or not n is 1. If n is 1, the process proceeds to step S9. If n is not 1, the process proceeds to step S3. [Step S3] It is determined whether n is 2. If n is 2, the process proceeds to step S11, and if n is not 2, the process proceeds to step S4. [Step S4] It is determined whether or not the previously read block is Gbb. If it is Gbb, the process proceeds to step S16. If it is not Gbb, the process proceeds to step S5.

  [Step S5] It is determined whether n is 3. If n is 3, the process proceeds to step S13. If n is not 3, the process proceeds to step S6. [Step S6] One block is read. [Step S7] It is determined whether or not the read block is Gbb. If it is Gbb, the process proceeds to step S14. If it is not Gbb, the process proceeds to step S8. [Step S8] The tool direction command is corrected by equation (5), and the process proceeds to step S15. [Step S9] When n is 1 in step S2, one block is read, and the process proceeds to step S10.

  [Step S10] The tool direction command is corrected by Equation 3 and the process proceeds to Step S15. [Step S11] Read two blocks, and proceed to Step S12. [Step S12] The tool direction command is corrected by the equation (4), and the process proceeds to Step S15. [Step S13] Two blocks are read, and the process proceeds to Step S7. [Step S14] The tool direction command is corrected by the equation (6), and the process proceeds to Step S15. [Step S15] Add 1 to n and return to Step S2. [Step S16] The tool direction command is corrected by equation (7), and the process ends.

  FIG. 13 is a principal block diagram of a numerical controller (CNC) 100 that executes the embodiment of the invention of the prior application. The CPU 11 is a processor that controls the numerical controller 100 as a whole. The CPU 11 reads out a system program stored in the ROM 12 via the bus 20 and controls the entire numerical control device according to the system program. The RAM 13 stores temporary calculation data, display data, and various data input by the operator via the display / MDI unit 70.

  The CMOS memory 14 is configured as a non-volatile memory that is backed up by a battery (not shown) and that retains the memory state even when the numerical controller 100 is turned off. In the CMOS memory 14, a machining program read via the interface 15, a machining program input via the display / MDI unit 70, and the like are stored. The ROM 12 is pre-stored with various system programs for executing processing in an edit mode and processing for automatic operation required for creating and editing a machining program.

  A machining program including command point sequence data and vector sequence data created using a CAD / CAM device or a copying device is input via the interface 15 and stored in the CMOS memory 14. A machining program having a tool direction command correction mode of the embodiment of the prior invention is also stored in the CMOS memory 14.

  Further, the machining program edited in the numerical controller 100 can be stored in an external storage device via the interface 15. The PMC (programmable machine controller) 16 is a sequence program built in the numerical control device 100 and is connected to an auxiliary device of a machine tool (for example, an actuator such as a robot hand for tool change) via an I / O unit 17. Output signal and control. In addition, it receives signals from various switches of the operation panel 75 provided in the machine tool body, performs necessary signal processing, and then passes them to the CPU 11.

  The display / MDI unit 70 is a manual data input device having a display, a keyboard, and the like. The interface 15 receives commands and data from the keyboard of the display / MDI unit 70 and passes them to the CPU 11. The interface 19 is connected to an operation panel 75 having a manual pulse generator and the like.

  The axis control circuits 30 to 34 for each axis receive the movement command amount for each axis from the CPU 11 and output the command for each axis to the servo amplifiers 40 to 44. In response to this command, the servo amplifiers 40 to 44 drive the servo motors 50 to 54 of the respective axes. The servo motors 50 to 54 for each axis have built-in position / speed control detectors. The position / speed feedback signals from the position / speed detectors are fed back to the axis control circuits 30 to 34 for position / speed feedback control. Do.

The servo motors 50 to 54 are for driving the X, Y, Z, B (A), and C axes of the 5-axis processing machine. The spindle control circuit 60 receives a spindle rotation command and outputs a spindle speed signal to the spindle amplifier 61. The spindle amplifier 61 receives the spindle speed signal and rotates the spindle motor 62 at the commanded rotational speed. The position coder 63 feeds back a feedback pulse to the spindle control circuit 60 in synchronization with the rotation of the spindle motor 62 to perform speed control.
The numerical control device 100 as described above can drive and control the 5-axis processing machine shown in FIG.

Next, an embodiment of a numerical controller of the present invention will be described with reference to the drawings.
Calculate the difference between the optimal tool direction and the original tool direction in each block of the machining program (hereinafter referred to as "ideal correction amount") in the numerical control device A of the prior invention, and create a frequency distribution of the ideal correction amount Added to the output function. In addition, a function for calculating and outputting the frequency distribution statistics (minimum value, maximum value, average value, variance, etc.) of the ideal correction amount as needed, and a function for creating and outputting the frequency distribution of the actual correction amount A function of calculating and outputting a frequency distribution statistic (minimum value, maximum value, average value, variance, etc.) of the actual correction amount may be added. The numerical control device A in the present invention is hereinafter referred to as a numerical control device B.

  An operator can set an appropriate allowable correction amount based on such information and machine configuration information. Here, the machine configuration information will be described. Since a larger allowable correction amount is more likely to be corrected, a larger value is desirable. Generally, when the allowable correction amount is large, the correction amount actually applied also increases. Depending on the machine, if a large correction is applied in the tool direction, the tool may interfere with the jig or workpiece. It is desirable for the operator to specify as large a value as possible, considering the allowance until the tool direction in the machining program interferes with the jig or workpiece. That is, the machine configuration information is simply information on how much the tool direction can be changed before the tool interferes with the jig or the workpiece in the machining program.

  When the variation of the ideal correction amount is large, it is necessary to set a very large value for the allowable correction amount in order to bring all the blocks sufficiently close to the optimum tool direction. Therefore, in the present invention, the numerical controller B has a correction amount value (hereinafter referred to as “recommended correction amount”) in which the cumulative relative frequency becomes a specified value (0.0 to 1.0) in the frequency distribution of the ideal correction amount. Is output). For example, by setting the recommended correction amount when the cumulative relative frequency is 0.9 as the allowable correction amount, the corrected tool direction is sufficiently close to the optimal tool direction in 90% of the blocks of the entire machining program. The operator can set an appropriate allowable correction amount based on the information and the machine configuration information. Further, the recommended correction amount calculated by the numerical controller B can be automatically set as the allowable correction amount.

  In the present invention, the numerical controller B corrects the tool direction by adding a function of outputting a frequency distribution table or frequency distribution diagram of the actual correction amount, which is the difference between the corrected tool direction and the original tool direction. It can be confirmed how was applied.

  Table 1 described above is an example of a program command in the machining program. Here, Gaa is a tool direction command correction mode, and Gbb is a G code for instructing to release the tool direction command correction mode. An example of a command of 10 blocks is given between Gaa and Gbb, but the number of blocks is not limited. X, Y, and Z represent three linear axes, and B and C represent two rotational axes. Each axis position command is an absolute command. Further, although the two rotation axes are represented by the B axis and the C axis, the same applies to other axis names such as the A and B axes or the A and C axes.

  The numerical controller B reads Gaa and enters the tool direction command correction mode, and calculates the optimum tool direction in each read block until Gbb is read and the tool direction command correction mode is canceled. Also, a sub-optimal tool direction is calculated based on the specified correction allowance. The tool direction of each block is represented by a set of values of addresses B and C, and is assumed to be Vn (Pbn, Pcn) (n = 1 to 10). The optimum tool direction corresponding to the tool direction Vn in each block calculated by the numerical controller B is Vn ′ (Pbn ′, Pcn ′) (n = 1 to 10), and the suboptimal tool direction is Vn ″ ( Pbn ″, Pcn ″) (n = 1 to 10).

The numerical controller B calculates ideal correction amounts βn ′ and γn ′ for each block as follows and summarizes them in a frequency distribution table (see FIG. 14).
1) βn ′ = | Pbn′−Pbn | and γn ′ = | Pcn′−Pcn | (n = 1 to 10) are calculated.
2) Based on βn ′ (n = 1 to 10), a frequency distribution table of ideal correction amounts for the B axis is created.
3) Based on γn ′ (n = 1 to 10), a frequency distribution table of ideal correction amounts for the C axis is created.
The numerical controller B calculates each statistic based on the created frequency distribution table.
4) Calculate the average value, maximum value, and minimum value of the frequency distribution table of the ideal correction amount for the B-axis and C-axis.
5) In the frequency distribution table of ideal correction amounts on the B axis and C axis, the value of the ideal correction amount that becomes the specified cumulative relative frequency is calculated.
Further, the numerical control device B calculates the actual correction amount in each block as follows, and summarizes it in the frequency distribution table.
6) βn ″ = | Pbn ″ −Pbn | and γn ″ = | Pcn ″ −Pcn | (n = 1 to 10) are calculated.
7) Based on βn ″ (n = 1 to 10), a frequency distribution table of actual correction amounts for the B axis is created.
8) Based on γn ″ (n = 1 to 10), a frequency distribution table of the actual correction amount of the C axis is created.

  FIG. 14 is a diagram for explaining a frequency distribution table of ideal correction amounts according to the present invention. The horizontal axis is the correction amount (angle), and the vertical axis is the number of tool direction commands corresponding to each correction amount. The horizontal axis shows the frequency distribution of the number of tool direction indices in increments of 0.1 degrees. FIG. 14 shows that the tool direction is corrected within a range of 0.7 degrees. In FIG. 14, the number of tool direction commands decreases as the correction amount increases.

FIG. 15 is a diagram for explaining that frequency function data is output to an external device by pressing a function key. Reference numeral 70 is a schematic diagram of a display device with an input device included in the numerical controller B.
The keyboard 73 includes numeric keys, alphabet keys, and the like. A prompt 74 is displayed on the display screen 71 to input the cumulative relative frequency (%). The external device includes storage means for storing frequency distribution data and a display device for displaying the frequency distribution, such as a personal computer.
For example, an instruction for the operator to set what percentage of the tool direction command to sufficiently correct is assigned to “F5” of the function key 72. The value entered with the numeric keys of the keyboard 73 is displayed at the prompt 74, and the value can be set by pressing F5. Further, an instruction to output frequency distribution data to an external device (not shown) is assigned to “F6” of the function key 72, and the frequency distribution data can be transmitted to the external device by pressing F6.

  FIG. 16 shows that when 50% is input to the prompt in FIG. 15 and is set by F5 of the function key, the cumulative frequency up to 0.2 degrees exceeds 50% of the entire distribution, and 0.2 degrees is automatically set as the allowable correction amount. It is shown that it is set automatically. The numerical control device B according to the present invention calculates the minimum value or the cumulative frequency up to the correction value equal to the allowable correction amount exceeds the specified ratio of the entire frequency distribution if the allowable correction amount is any number. It has a function of automatically setting a value as an optimum allowable correction amount.

  FIG. 17 is a graph showing the cumulative frequency distribution of ideal correction amounts. This graph is obtained based on the frequency distribution of the ideal correction amount shown in FIG. The horizontal axis represents the correction amount and the number of tool direction commands for each predetermined correction amount in increments of 0.1 degrees. FIG. 18 is a graph showing the cumulative relative frequency distribution of the ideal correction amount. Based on the graph of the cumulative frequency distribution shown in FIG. 17, the vertical axis represents the cumulative relative frequency from 0 to 1.0.

Next, a flowchart of the processing algorithm of the present invention will be described. This process is executed by the processor (CPU) of the numerical controller shown in FIG.
FIG. 19 and FIG. 20 are flowcharts showing an algorithm of processing for updating the frequency distribution of the correction amount and recalculating the statistical amount of the frequency distribution every time the block is corrected. In this flowchart, every time a block is corrected, the frequency distribution of the correction amount is updated, and the statistics of the frequency distribution are recalculated. In this flowchart, the statistics of the frequency distribution of the blocks up to that point can be known at any time. Further, this flowchart shows processing after reading Gaa in Table 1. It is assumed that at least 5 blocks are commanded between Gaa and Gbb. Hereinafter, it demonstrates according to each step.

[Step SA1] n is set to 1. Here, n corresponds to the number of tool direction commands.
[Step SA2] It is determined whether or not n is 1. If n is 1, the process proceeds to step SA9, and if n is not 1, the process proceeds to step SA3.
[Step SA3] It is determined whether n is 2. If n is 2, the process proceeds to step SA11. If n is not 2, the process proceeds to step SA4.
[Step SA4] It is determined whether or not the previously read block is Gbb. If it is Gbb, the process proceeds to Step SA20. If it is not Gbb, the process proceeds to Step SA5.

[Step SA5] It is determined whether n is 3. If n is 3, the process proceeds to step SA13. If n is not 3, the process proceeds to step SA6.
[Step SA6] One block is read.
[Step SA7] It is determined whether or not the read block is Gbb. If it is Gbb, the process proceeds to Step SA14, and if it is not Gbb, the process proceeds to Step SA8.
[Step SA8] The tool direction command is corrected by the equation (5), and the process proceeds to Step SA15.
[Step SA9] When n is 1 in Step SA2, one block is read, and the process proceeds to Step SA10.

[Step SA10] The tool direction command is corrected by the equation (3), and the process proceeds to Step SA15.
[Step SA11] Two blocks are read, and the process proceeds to Step SA12.
[Step SA12] The tool direction command is corrected by the equation (4), and the process proceeds to Step SA15.
[Step SA13] Two blocks are read, and the process proceeds to Step SA7.
[Step SA14] The tool direction command is corrected by Equation 6 and the process proceeds to Step SA15.

[Step SA15] 1 is added to n.
[Step SA16] The set value of the allowable range is read.
[Step SA17] It is determined whether or not the ideal correction amount of the tool direction command is within the preset allowable range read in Step SA16. If it is within the allowable range, the process proceeds to Step SA19 and is outside the allowable range. If so, the process proceeds to step SA18.
[Step SA18] A sub-optimal tool direction is calculated.
[Step SA19] Using the original tool direction, the optimum tool direction, and the suboptimal tool direction data calculated this time, the ideal correction amount and the actual correction amount are obtained and stored in the memory. The frequency distribution and cumulative frequency distribution for each predetermined correction amount are updated for the ideal correction amount and the actual correction amount. The statistics of each frequency distribution are recalculated, stored in the memory, and the process proceeds to step SA2.
[Step SA20] The tool direction command is corrected by the equation (7), and the process ends.

Here, the process of step SA19 will be described. The original tool direction is the tool direction before performing the tool correction commanded by the tool direction command. The optimum tool direction is the tool direction in which the tool direction command is corrected by the formulas 3 to 6. The quasi-optimal tool direction is the tool direction when the tool direction is corrected within a preset allowable range. For example, when the optimum tool direction exceeds the allowable range, the sub-optimal tool direction is obtained by calculation with the tool direction limited by the correction amount at the limit of the allowable range.
In addition, processing that does not substantially limit the allowable range or does not set in advance, calculates the ideal correction amount for the optimal tool direction and obtains the frequency distribution of the ideal correction amount, and does not calculate the frequency distribution for the actual correction amount There are also forms.
The calculation method of the ideal correction amount and the actual correction amount is as described above.

FIG. 21 and FIG. 22 show processing for updating the correction amount frequency distribution until the designated m block is read, calculating the statistics of the frequency distribution when the designated m block is read, and thereafter not updating the frequency distribution. It is a flowchart which shows an algorithm.
In this flowchart, after Gaa is read, the correction amount frequency distribution is updated until the designated m block is read, and the frequency distribution statistic is calculated when the m block is read, and thereafter the frequency distribution is updated. There is no example. In this flowchart, since the calculation of statistics is not performed for each block, the calculation amount for each block can be reduced as compared with the flowcharts shown in FIGS. 19 and 20, and the number m of blocks for calculating statistics can be set. There is.
Further, this flowchart shows processing after reading Gaa in Table 1. It is assumed that at least 5 blocks are commanded between Gaa and Gbb. Hereinafter, it demonstrates according to each step.

[Step SB1] n is set to 1. Here, n corresponds to the number of tool direction commands.
[Step SB2] It is determined whether or not n is 1. If n is 1, the process proceeds to step SB9, and if n is not 1, the process proceeds to step SB3.
[Step SB3] It is determined whether n is 2. If n is 2, the process proceeds to step SB11. If n is not 2, the process proceeds to step SB4.
[Step SB4] It is determined whether or not the previously read block is Gbb. If it is Gbb, the process proceeds to Step SB24, and if it is not Gbb, the process proceeds to Step SB5.

[Step SB5] It is determined whether n is 3. If n is 3, the process proceeds to step SB13. If n is not 3, the process proceeds to step SB6.
[Step SB6] One block is read.
[Step SB7] It is determined whether or not the read block is Gbb. If it is Gbb, the process proceeds to step SB14. If it is not Gbb, the process proceeds to step SB8.
[Step SB8] The tool direction command is corrected by the equation (5), and the process proceeds to Step SB15.
[Step SB9] When n is 1 in Step SB2, 1 block is read, and the process proceeds to Step SB10.

[Step SB10] The tool direction command is corrected by Equation 3 and the process proceeds to Step SB15.
[Step SB11] Two blocks are read, and the process proceeds to Step SB12.
[Step SB12] The tool direction command is corrected by the equation (4), and the process proceeds to Step SB15.
[Step SB13] Two blocks are read, and the process proceeds to Step SB7.
[Step SB14] The tool direction command is corrected by the equation (6), and the process proceeds to Step SB15.
[Step SB15] 1 is added to n.

[Step SB16] The set value of the allowable range is read.
[Step SB17] m is read. m is a numerical value for setting how many blocks are read before calculating the statistics of the frequency distribution.
[Step SB18] It is determined whether or not the ideal correction amount of the tool direction command is within the preset allowable range read in Step SB16. If the ideal correction amount is within the allowable range, the process proceeds to Step SB20. If so, the process proceeds to step SB19.
[Step SB19] A sub-optimal tool direction is calculated.
[Step SB20] It is determined whether or not n is larger than m + 1. If larger, the process proceeds to Step SB2, and if not larger, the process proceeds to Step SB21.
[Step SB21] Using the original tool direction, optimum tool direction, and suboptimal tool direction data calculated this time, the ideal correction amount and the actual correction amount are obtained and stored in the memory. The frequency distribution and cumulative frequency distribution for each predetermined correction amount are updated for the ideal correction amount and the actual correction amount.
[Step SB22] It is determined whether or not n is m + 1. If n is not m + 1, the process proceeds to step SB2, and if n is m + 1, the process proceeds to step SB23.
[Step SB23] The statistics of each frequency distribution are calculated.
[Step SB24] The tool direction command is corrected according to Equation 7, and the process ends.

  Here, the process of step SB21 will be described. The original tool direction is the tool direction before performing the tool correction commanded by the tool direction command. The optimum tool direction is the tool direction in which the tool direction command is corrected by the formulas 3 to 6. The quasi-optimal tool direction is the tool direction when the tool direction is corrected within a preset allowable range. For example, when the optimum tool direction exceeds the allowable range, the sub-optimal tool direction is obtained by calculation with the tool direction limited by the correction amount at the limit of the allowable range. Each frequency distribution in step SB23 is a frequency distribution of ideal correction amounts and a frequency distribution of actual correction amounts.

  FIG. 23 and FIG. 24 are flowcharts showing an algorithm of processing for calculating the statistics of the frequency distribution at the end of the program. In this flowchart, the statistics of the frequency distribution are calculated at the end of the machining program. Compared with the case of calculating the statistics for each block, there is an effect that processing is reduced. In addition, the process after the tool direction command after reading Gaa of Table 1 is read is shown. Hereinafter, it demonstrates according to each step.

[Step SC1] n is set to 1. Here, n corresponds to the number of tool direction commands.
[Step SC2] It is determined whether or not n is 1. If n is 1, the process proceeds to step SC9. If n is not 1, the process proceeds to step SC3.
[Step SC3] It is determined whether n is 2. If n is 2, the process proceeds to step SC11. If n is not 2, the process proceeds to step SC4.
[Step SC4] It is determined whether or not the previously read block is Gbb. If it is Gbb, the process proceeds to step SC20. If it is not Gbb, the process proceeds to step SC5.

[Step SC5] It is determined whether n is 3. If n is 3, the process proceeds to step SC13. If n is not 3, the process proceeds to step SC6.
[Step SC6] One block is read.
[Step SC7] It is determined whether or not the read block is Gbb. If it is Gbb, the process proceeds to step SC14. If it is not Gbb, the process proceeds to step SC8.
[Step SC8] The tool direction command is corrected by the equation (5), and the process proceeds to Step SC15.
[Step SC9] If n is 1 in step SC2, read one block and proceed to step SC10.

[Step SC10] The tool direction command is corrected by the equation (3), and the process proceeds to Step SC15.
[Step SC11] Read two blocks, and proceed to Step SC12.
[Step SC12] The tool direction command is corrected by the equation (4), and the process proceeds to Step SC15.
[Step SC13] Two blocks are read, and the process proceeds to Step SC7.
[Step SC14] The tool direction command is corrected by the equation (6), and the process proceeds to Step SC15.
[Step SC15] 1 is added to n.

[Step SC16] The set value of the allowable range is read.
[Step SC17] It is determined whether or not the ideal correction amount of the tool direction command is within the preset allowable range read in Step SC16. If the ideal correction amount is within the allowable range, the process proceeds to Step SC19. If so, the process proceeds to step SC18.
[Step SC18] A sub-optimal tool direction is calculated.
[Step SC19] Using the original tool direction, optimum tool direction, and sub-optimal tool direction data calculated this time, an ideal correction amount and an actual correction amount are obtained and stored in the memory. The frequency distribution and cumulative frequency distribution for each predetermined correction amount are updated for the ideal correction amount and the actual correction amount.
[Step SC20] The tool direction command is corrected by the equation (7), and the process proceeds to Step SC21.
[Step SC21] The statistics of each frequency distribution in step SC19 are calculated, and the process ends.

  Here, the process of step SC19 will be described. The original tool direction is the tool direction before performing the tool correction commanded by the tool direction command. The optimum tool direction is the tool direction in which the tool direction command is corrected by the formulas 3 to 6. The quasi-optimal tool direction is the tool direction when the tool direction is corrected within a preset allowable range. For example, when the optimum tool direction exceeds the allowable range, the sub-optimal tool direction is obtained by calculation with the tool direction limited by the correction amount at the limit of the allowable range.

  In addition, processing that does not substantially limit the allowable range or does not set in advance, calculates the ideal correction amount for the optimal tool direction and obtains the frequency distribution of the ideal correction amount, and does not calculate the frequency distribution for the actual correction amount There are also forms. The calculation method of the ideal correction amount and the actual correction amount is as described above.

  In the above flowchart, “n” integration corresponds to an accumulating unit that accumulates the number of tool direction commands. The input of the ratio of the cumulative frequency to the prompt 74 shown in FIG. 15 corresponds to a ratio specifying means for specifying a ratio with respect to the number of tool commands. The cumulative frequency distribution can be obtained by accumulating the number of tool direction commands for each predetermined correction amount. Obtaining the cumulative frequency corresponding to the value input from the prompt 74 corresponds to an acquisition unit that acquires the ideal correction amount of the tool direction command. The setting means for setting as the allowable range stores the value acquired by the acquisition means in the memory of the numerical controller.

DESCRIPTION OF SYMBOLS 1 Command reading means 2 Tool direction command correction means 3 Interpolation means 4X, 4Y, 4Z, 4B (A), 4C Each axis servo 70 Display / MDI unit 71 Display screen 72 Function key 73 Keyboard 74 Prompt

Claims (5)

Controls a 5-axis processing machine composed of 3 linear axes and 2 rotary axes for processing a workpiece mounted on a table, and moves the linear axis relative to the workpiece and tool. Command reading means for reading a tool direction command as a moving speed command and a tool direction with respect to the table;
An optimum tool direction is calculated from the tool direction command, and a sub-optimal tool direction is calculated so that a difference between the tool direction command and the calculated optimum tool direction is within a preset allowable range. Tool direction command correcting means for correcting the tool direction command by setting the quasi-optimal tool direction as the tool direction of the tool direction command;
A tool tip point is commanded on the basis of the tool direction command corrected by the tool direction command correcting means, the movement path command, and the relative movement speed command, and is moved every interpolation cycle so as to move at the commanded relative movement speed. In the numerical control device of a 5-axis processing machine, which has interpolation means for obtaining each axis position and means for driving each axis motor so as to move to each axis position obtained by the interpolation means,
Ideal correction amount calculation means for calculating an ideal correction amount that is a difference between the tool direction command and the optimum tool direction calculated by the tool direction command correction means;
Ideal correction amount storage means for storing the ideal correction amount calculated by the ideal correction amount calculation means;
Output means for outputting the ideal correction amount stored in the ideal correction amount storage means as a frequency distribution of the tool direction command for each predetermined correction amount;
A numerical control device for a 5-axis machine characterized by comprising:   The output unit displays the ideal correction amount stored in the ideal correction amount storage unit as a frequency distribution of the tool direction command for each predetermined correction amount, or a display device provided in the numerical control device or the numerical control device. The numerical control device for a 5-axis machining apparatus according to claim 1, wherein the numerical control device is a display device of a connected external device. Accumulating means for accumulating the number of tool direction commands;
A ratio specifying means for specifying a ratio with respect to the number of the tool direction commands;
Cumulative frequency distribution obtaining means for accumulating the number of tool direction commands in order from a small value of the ideal correction amount of the tool direction command to obtain a cumulative frequency distribution;
Obtaining means for obtaining an ideal correction amount of the tool direction command when the accumulated number of the tool direction commands coincides with the number of tool direction commands corresponding to the proportion designated by the proportion designation means;
Setting means for setting the ideal correction amount acquired by the acquisition means as the preset allowable range;
The numerical control device for a 5-axis machining apparatus according to claim 1, wherein: The numerical control device includes an actual correction amount calculating means for obtaining an actual correction amount when the tool direction command is corrected to the semi-optimal tool direction;
Actual correction amount storage means for storing the actual correction amount calculated by the actual correction amount calculation means;
4. The actual correction amount stored in the actual correction amount storage unit is output to the output unit as a frequency distribution of the tool direction command for each predetermined correction amount. A numerical control device for a five-axis processing machine according to claim 1. Statistic calculation means for calculating a statistic based on the frequency distribution of the tool direction command for each of the ideal correction amount and the actual correction amount;
The numerical control device for a 5-axis machining apparatus according to claim 4, wherein the statistical amount calculated by the statistical amount calculation means is output to the output means.

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