JP6623902B2 - Processing path calculation device, processing path calculation method, and computer program - Google Patents

Description

  The present invention relates to a machining path calculation device, a machining path calculation method, and a computer program for calculating a path of a spindle for processing a workpiece.

  When a machine tool processes a work, the processing device calculates the processing path of the spindle before processing the work, and calculates the shape (model) of the processed work based on the calculated processing path. The arithmetic unit generates a surface shape of the model based on the image data (rendering).

  The arithmetic unit compares one pixel constituting the surface of the model with another pixel adjacent to the one pixel, obtains a change rate of the normal vector, and calculates a change rate of the direction of the surface. The arithmetic unit assigns a color corresponding to the rate of change of the surface orientation to each pixel. An operator can visually recognize a defect on the model surface (for example, see Patent Document 1).

Japanese Patent No. 5666013

  However, in order to generate the surface shape of the model, an expensive arithmetic unit capable of high-speed processing is required, and the cost increases.

  The present invention has been made in view of such circumstances, and provides a machining path calculation device, a machining path calculation method, and a computer program that can recognize a defect on a model surface at low cost without generating a model. With the goal.

  A processing path calculation device according to the present invention is a processing path calculation device that calculates a processing path for processing a workpiece based on a plurality of command points that indicate a position of a spindle, wherein an evaluation cross section intersecting the processing path is determined. A setting part to be set, an intersection calculating part for calculating an intersection of the evaluation cross section and the machining path set by the setting part, and an intersection calculated by the intersection calculating part indicate a degree of unevenness of the work surface after processing. The image processing apparatus is characterized by comprising: a feature value calculation unit that calculates a feature value; and a generation unit that generates image data corresponding to the feature value calculated by the feature value calculation unit.

  In the machining path calculation device according to the present invention, the intersection calculation unit may include a first intersection, a second intersection having coordinates larger than the coordinates of the first intersection in a direction parallel to the evaluation section, and the intersection in the direction. A coordinate calculation unit configured to calculate a third intersection having coordinates smaller than the coordinates of the first intersection, wherein the feature amount calculation unit calculates the third intersection based on the coordinates of the first intersection, the second intersection, and the third intersection. It is characterized by including a second-order difference calculation unit that calculates a second-order difference at one intersection.

  In the machining path calculation device according to the present invention, the intersection calculation unit calculates a plurality of intersections, and the feature calculation unit sets and sets a curve using a plurality of other intersections around one intersection. And a distance calculating unit that projects a corresponding point corresponding to the one intersection on the set curve and calculates a distance between the corresponding point and the one intersection.

  In the machining path calculation device according to the present invention, the intersection calculation unit calculates a plurality of intersections, and the feature calculation unit calculates a fourth intersection and a fifth intersection and a sixth intersection respectively located on both sides of the fourth intersection. And an angle calculation unit that calculates an intersection and calculates an angle formed by a line segment connecting the fourth intersection point and the fifth intersection point and a line segment connecting the fourth intersection point and the sixth intersection point.

  The processing path calculation device according to the present invention includes a determination unit that determines whether a feature value calculated by the feature value calculation unit is equal to or smaller than a preset threshold value, and the generation unit includes When it is determined that the feature value calculated by the feature value calculation unit is equal to or less than the threshold, first image data is generated, and the feature value calculated by the feature value calculation unit by the determination unit is set to the threshold value. When it is determined that the amount of data has exceeded the second image data, second image data that displays the feature amount in a format different from that of the first image data is generated.

  A machining path calculation method according to the present invention is a machining path calculation method for calculating a machining path for machining a workpiece based on a plurality of command points indicating a position of a spindle. An intersection of the set evaluation cross section and the machining path is calculated, a feature amount indicating the degree of unevenness of the processed work surface is calculated with respect to the calculated intersection, and image data corresponding to the calculated feature amount is generated. It is characterized by the following.

  A computer program according to the present invention is a computer program executable by a machining path calculation device for calculating a machining path for machining a workpiece based on a plurality of command points indicating a position of a spindle, wherein the machining path calculation device In addition, an evaluation cross section intersecting the processing path is set, an intersection of the set evaluation cross section and the processing path is calculated, and a characteristic amount indicating a degree of unevenness of the work surface after processing is calculated with respect to the calculated intersection. A process of generating image data corresponding to the calculated feature amount.

  In the present invention, a feature amount indicating the degree of unevenness of the processed work surface is calculated for an intersection between the evaluation section and the processing path, and image data corresponding to the calculated feature amount is generated. The work surface after processing can be displayed by the generated image data without generating the work shape after processing.

  In the present invention, the first intersection, the second intersection, and the third intersection are calculated, and the second order difference of the first intersection is calculated based on the calculated coordinates of the first intersection, the second intersection, and the third intersection. Based on the calculated second order difference, the calculation of the feature amount is realized.

  In the present invention, a curve (for example, a spline curve, a Bezier curve, or a NURBS curve) is set using a plurality of other intersections around one intersection. A corresponding point corresponding to one intersection is projected on the curve, and a distance between the corresponding point and one intersection is calculated. The calculation of the feature amount is realized based on the calculated distance.

  In the present invention, the fourth intersection, the fifth intersection, and the sixth intersection are calculated, and the angle formed by the line connecting the fourth intersection and the fifth intersection and the line connecting the fourth intersection and the sixth intersection is calculated. . The calculation of the characteristic amount is realized based on the calculated angle.

  In the present invention, when it is determined that the feature value is equal to or less than the threshold value, first image data (for example, blue image data) is generated, and when it is determined that the feature value exceeds the threshold value, the first image data Second image data (for example, red image data) that displays the feature amount in a different format is generated. An operator can visually recognize an image formed by the first image data and the second image data and recognize a defect.

  In the machining path calculation device, the machining path calculation method, and the computer program according to the present invention, the feature calculated and calculated with respect to the intersection between the evaluation section and the processing path, which indicates the degree of unevenness of the work surface after processing. Generate image data corresponding to the quantity. Therefore, the display device can display the processed work surface on the display device based on the generated image data without generating the processed work shape, and the operator can visually recognize the defect on the work surface. can do.

FIG. 2 is a perspective view schematically illustrating the machine tool according to the first embodiment. FIG. 2 is a block diagram schematically illustrating a configuration of a control device. FIG. 3 is a plan view schematically showing a processing path and an evaluation cross section for a work. It is a perspective view which briefly shows the evaluation cross section with respect to a workpiece. FIG. 4 is a schematic diagram schematically showing a command point and an intersection of an evaluation section and a machining path. It is a conceptual diagram showing an example of an intersection table. FIG. 9 is an explanatory diagram illustrating a first calculation method for calculating a feature amount of an intersection on an evaluation section. FIG. 9 is an explanatory diagram illustrating a second calculation method for calculating a feature amount of an intersection on an evaluation section. FIG. 9 is an explanatory diagram illustrating a third calculation method for calculating a feature amount of an intersection on an evaluation section. FIG. 3 is a conceptual diagram illustrating an example of a color table indicating a relationship between a feature amount and a color. 5 is a flowchart illustrating a feature value calculation process performed by a control device. FIG. 13 is a plan view schematically showing a machining path and an evaluation cross section for a workpiece according to a second embodiment. It is explanatory drawing explaining the setting of an evaluation cross section. FIG. 9 is a plan view schematically showing a processing path and an evaluation cross section for a work in a modification.

(Embodiment 1)
Hereinafter, the present invention will be described with reference to the drawings showing a machine tool according to a first embodiment. In the following description, upper and lower, right and left, and front and rear indicated by arrows in the drawings will be used. FIG. 1 is a perspective view schematically showing a machine tool.

  The machine tool includes a rectangular base 1 extending in the front-back direction. A work holding part 3 for holding a work is provided on the front side of the upper part of the base 1. The work holding part 3 is rotatable around an A-axis whose axial direction is the left-right direction and a C-axis whose axial direction is the vertical direction.

  A support 2 for supporting a column 4 described below is provided on the rear side of the upper portion of the base 1. A Y-axis direction moving mechanism 10 that moves in the front-rear direction is provided above the support base 2. The Y-axis direction moving mechanism 10 includes two rails 11 extending forward and backward, a Y-axis screw shaft 12, a Y-axis motor 13, and a bearing 14.

  The rails 11 are provided on the left and right of the upper part of the support 2. The Y-axis screw shaft 12 extends back and forth and is provided between the two rails 11. A bearing 14 is provided at each of the front end and the middle of the Y-axis screw shaft 12. The illustration of the bearing provided in the middle part is omitted. The Y-axis motor 13 is connected to the rear end of the Y-axis screw shaft 12.

  A nut (not shown) is screwed to the Y-axis screw shaft 12 via a rolling element (not shown). The rolling element is, for example, a ball. A plurality of sliders 15 are slidably provided on each rail 11. The moving plate 16 is connected to the upper part of the nut and the slider 15. The moving plate 16 extends in the horizontal direction. The rotation of the Y-axis motor 13 rotates the Y-axis screw shaft 12, the nut moves in the front-back direction, and the moving plate 16 moves in the front-back direction.

  An X-axis direction moving mechanism 20 that moves in the left-right direction is provided on the upper surface of the moving plate 16. The X-axis direction moving mechanism 20 includes two rails 21 extending left and right, an X-axis screw shaft 22, an X-axis motor (not shown), and a bearing 24.

  The rails 21 are provided at the front and rear of the upper surface of the moving plate 16 respectively. The X-axis screw shaft 22 extends left and right and is provided between the two rails 21. Bearings 24 are provided at the left end and the middle of the X-axis screw shaft 22, respectively. The description of the bearing provided in the middle of the X-axis screw shaft 22 is omitted. The X-axis motor is connected to the right end of the X-axis screw shaft 22.

  A nut (not shown) is screwed to the X-axis screw shaft 22 via a rolling element (not shown). Grease is applied to the X-axis screw shaft 22. A plurality of sliders 26 are slidably provided on each rail 21. The column 4 is connected to an upper portion of the nut and the slider 26. The column 4 has a columnar shape. The rotation of the X-axis motor rotates the X-axis screw shaft 22, the nut moves in the left-right direction, and the column 4 moves in the left-right direction.

  A Z-axis direction moving mechanism 30 that moves in the vertical direction is provided on the front surface of the column 4. The Z-axis direction moving mechanism 30 includes two rails 31 extending vertically, a Z-axis screw shaft 32, a Z-axis motor 33, and a bearing 34.

  The rails 31 are provided on the left and right sides of the front surface of the column 4. The Z-axis screw shaft 32 extends vertically and is provided between the two rails 31. A bearing 34 is provided at each of a lower end portion and an intermediate portion of the Z-axis screw shaft 32. The illustration of the bearing provided in the middle part is omitted. The Z-axis motor 33 is connected to the upper end of the Z-axis screw shaft 32.

  A nut (not shown) is screwed to the Z-axis screw shaft 32 via a rolling element (not shown). Grease is applied to the Z-axis screw shaft 32. A plurality of sliders 35 are slidably provided on each rail 31. The spindle head 5 is connected to a front portion of the nut and the slider 35. The rotation of the Z-axis motor 33 causes the Z-axis screw shaft 32 to rotate, the nut to move up and down, and the spindle head 5 to move up and down. The Z-axis motor 33, the Z-axis screw shaft 32, the nut and the rolling elements constitute a ball screw mechanism.

  A vertically extending spindle 5 a is provided in the spindle head 5. The main shaft 5a rotates around the axis. A spindle motor 6 is provided at the upper end of the spindle head 5. A tool is mounted on the lower end of the main shaft 5a. The rotation of the spindle motor 6 rotates the spindle 5a, and the tool rotates. The rotated tool processes the work held by the work holding unit 3.

  The machine tool includes a tool changing device (not shown) for changing a tool. The tool changing device exchanges a tool housed in a tool magazine (not shown) and a tool mounted on the main shaft 5a.

FIG. 2 is a block diagram schematically showing the configuration of the control device 50. The control device 50 (processing path calculation device) includes a CPU 51, a storage unit 52, a RAM 53, and an input / output interface 54. The storage unit 52 is a rewritable memory, such as an EPROM or an EEPROM. The control device 50 controls the machine tool based on the control program stored in the storage unit 52. Intersection table storage unit 52 to be described later, the color table, the route number i, the command point P _k, intersection S _i ^d, and stores the final number of the k (d, i, k is a natural number). The control device 50 may include a ROM in which a control program is stored in advance.

  When the operator operates the operation unit 7, a signal is input from the operation unit 7 to the input / output interface 54. The operation unit 7 is, for example, a keyboard, a button, a touch panel, or the like. The input / output interface 54 outputs a signal to the display unit 8. The display unit 8 displays characters, figures, symbols, and the like. The display unit 8 is, for example, a liquid crystal display panel.

  The control device 50 includes an X-axis control circuit 55 corresponding to the X-axis motor 23, a servo amplifier 55a, and a differentiator 23b. The X-axis motor 23 includes an encoder 23a. The X-axis control circuit 55 outputs a command indicating a current amount to the servo amplifier 55a based on a command from the CPU 51. The servo amplifier 55a receives the command and outputs a drive current to the X-axis motor 23.

  The encoder 23a outputs a position feedback signal to the X-axis control circuit 55. The X-axis control circuit 55 executes position feedback control based on the position feedback signal.

  The encoder 23a outputs a position feedback signal to the differentiator 23b, and the differentiator 23b converts the position feedback signal into a speed feedback signal and outputs the converted signal to the X-axis control circuit 55. The X-axis control circuit 55 executes speed feedback control based on the speed feedback signal.

  The current detector 55b detects the value of the drive current output from the servo amplifier 55a. The current detector 55b feeds back the value of the drive current to the X-axis control circuit 55. The X-axis control circuit 55 executes current control based on the value of the drive current.

  The control device 50 includes a Y-axis control circuit 56 corresponding to the Y-axis motor 13, a servo amplifier 56a, and a differentiator 13b. The Y-axis motor 13 includes an encoder 13a. The Y-axis control circuit 56 outputs a command indicating a current amount to the servo amplifier 56a based on a command from the CPU 51. The servo amplifier 56a receives the command and outputs a drive current to the Y-axis motor 13.

  The encoder 13a outputs a position feedback signal to the Y-axis control circuit 56. The Y-axis control circuit 56 executes position feedback control based on the position feedback signal.

  The encoder 13a outputs a position feedback signal to the differentiator 13b, and the differentiator 13b converts the position feedback signal into a speed feedback signal and outputs the signal to the Y-axis control circuit 56. The Y-axis control circuit 56 performs speed feedback control based on the speed feedback signal.

  The current detector 56b detects the value of the drive current output from the servo amplifier 56a. The current detector 56b feeds back the value of the drive current to the Y-axis control circuit 56. The Y-axis control circuit 56 performs current control based on the value of the drive current.

  The control device 50 includes a Z-axis control circuit 57 corresponding to the Z-axis motor 33, a servo amplifier 57a, and a differentiator 33b. The Z-axis motor 33 includes an encoder 33a. The Z-axis control circuit 57 outputs a command indicating a current amount to the servo amplifier 57a based on a command from the CPU 51. The servo amplifier 57a receives the command and outputs a drive current to the Z-axis motor 33.

  The encoder 33a outputs a position feedback signal to the Z-axis control circuit 57. The Z-axis control circuit 57 executes position feedback control based on the position feedback signal.

  The encoder 33a outputs a position feedback signal to the differentiator 33b, and the differentiator 33b converts the position feedback signal into a speed feedback signal and outputs the converted signal to the Z-axis control circuit 57. The Z-axis control circuit 57 executes speed feedback control based on the speed feedback signal.

  The current detector 57b detects the value of the drive current output from the servo amplifier 57a. The current detector 57b feeds back the value of the drive current to the Z-axis control circuit 57. The Z-axis control circuit 57 executes current control based on the value of the drive current.

  The control device 50 also performs the same feedback control on the spindle motor 6 as the X-Z axis motors 23, 13, and 33.

  The machine tool includes a magazine motor 60 and a magazine control circuit 58. The rotation of the magazine motor 60 drives the tool magazine. The magazine control circuit 58 controls the rotation of the magazine motor 60.

The storage unit 52 stores a machining program for machining a work. The machining program has a plurality of command points _Pk indicating the position of the spindle 5a. k indicates the order of instructions constituting the machining program. The spindle 5a sequentially moves a plurality of command points _Pk , and the tool mounted on the spindle 5a processes a workpiece.

The storage unit 52 stores the command point _Pk in advance. The control device 50 sets a path (machining path) along which the main shaft 5a moves based on the plurality of command points _Pk . The control device 50 executes the movement of the main shaft 5a based on the machining path.

  A method for setting a machining path will be described. FIG. 3 is a plan view schematically showing a machining path and an evaluation cross section for the work, and FIG. 4 is a perspective view schematically showing an evaluation cross section for the work. In the drawings, the X direction indicates the left-right direction, the Y direction indicates the front-back direction, and the Z direction indicates the up-down direction. The shape of the workpiece in FIGS. 3 and 4 shows the shape after processing.

The control device 50 sets an evaluation section D ^d (d indicates a section number and is a natural number) for the workpiece. As shown in FIG. 3, when most of the main shaft 5a reciprocates along the X direction, the machining path is a path along the X direction. As shown in FIG. 3, the controller 50 sets a plurality of evaluation section D ^d along a direction substantially perpendicular to the machining path. The plurality of evaluation sections are arranged in the X direction. The operator instructs in advance that the machining path is in the X direction.

FIG. 5 is a schematic diagram schematically showing a command point _Pk and an intersection of an evaluation section ^Dd and a machining path, and FIG. 6 is a conceptual diagram showing an example of an intersection table. 5 and 6, "i" (i is a natural number) indicates a path number in the X-direction movement of the main shaft 5a. As shown in FIG. 5, for example, the route with the route number 1 (i = 1) indicates a route that moves from left to right, and the route with the route number 2 (i = 2) turns the route with the route number 1 back at the right end. To indicate a path moving from right to left. The same applies to route numbers 3 and below. The spindle 5a moves in the order of the path numbers.

As shown in FIG. 6, the control device 50, each evaluation section D ^d, the moving path P _k -P _k + ₁ calculates the intersection S _i ^d and the path number i, the intersection S _i ^d coordinates (X (Coordinates, Y coordinates and Z coordinates) and the movement route P _k -P _{k + 1} are stored in the intersection table in association with each other. Note that the X coordinate is a coordinate in the X direction, the Y coordinate is a coordinate in the Y direction, and the Z coordinate is a coordinate in the Z direction.

Controller 50 calculates a characteristic quantity of the intersection on evaluation section D ^d for example by the first calculation method. Figure 7 is an explanatory diagram for explaining a first calculation process for calculating a feature quantity of intersection on evaluation section D ^d. Controller 50, the intersection point S _i ^d Z coordinates and the intersection S _i-1 ^d (second intersection) located respectively on both sides of the intersection S _i ^d (first intersection) of interest and the intersection S _{i + 1} ^d use (third intersection) Z coordinates, calculates a second difference of the intersecting point S _i ^d. The Z coordinate of the intersection S _i-1 ^d is larger than the Z coordinate of the intersection S _i ^d . The Z coordinate of the intersection S _{i + 1} ^d is smaller than the Z coordinate of the intersection S _i ^d .

Controller 50 calculates the intersection S _i ^d Z coordinate z _i ^d and the intersection point S _{i + 1} ^d coordinate z _{i + 1} ^d of the difference d _a of ^{_{(d a = z i d -z}} i + 1 d) , calculates the intersection point S _i-1 ^d coordinate z _i-1 ^d and the intersection point S _i ^d coordinate z _i ^d of the difference d _b of the _{(d b = z i-1} d -z i d). Controller 50, a difference d _a difference d _a and the difference d _b - calculates a difference d _b (second order differential). The control device 50 calculates a second-order difference for all intersections, except for the intersection located at the end, in each evaluation section as a feature amount. The magnitude of the magnitude of the second order difference corresponds to the magnitude of the degree of unevenness of the work surface after processing.

Controller 50 calculates a characteristic quantity of the intersection on evaluation section D ^d for example, the second calculation method. Figure 8 is an explanatory diagram for explaining a second calculation process for calculating a feature quantity of intersection on evaluation section D ^d. In FIG. 8, u corresponds to the XY coordinates, and v corresponds to the Z coordinates.

The controller 50 uses the other of the plurality of intersections surrounding the intersection S _i ^d for example as a calculation target, a smooth curve (spline curves, Bezier curves, NURBS curve, etc.) to create a, on the curve by projecting the intersection S _i ^d, to create a corresponding point t _i ^d corresponding to the intersection S _i ^d.

When four intersections S _i−2 ^d , S _i−1 ^d , S _{i + 1} ^d and S _{i + 2} ^d are used as a smooth curve, the section S _i−2 on the evaluation section D ^d (uv plane) is used. curve expressions v ₁ (u), v ₂ (u), ^{d to} S _i-1 ^d , sections S _i-1 ^{d to} S _{i + 1} ^d , and sections S _{i + 1} ^{d to} S _{i + 2} ^d v ₃ (u) is given by the following equation.
v _j (u) = a _j (u-u _j ) ³ + b _j (u-u _j ) ² + c _j (u-u _j ) + d _j
(J = 1, 2, 3)

Based on the fact that the first and second derivatives pass through the intersections S _i−2 ^d , S _i−1 ^d , S _{i + 1} ^d and S _{i + 2} ^d and are continuous at the boundary points, 50 can determine a _{j to} d _j .

Selection of the four intersection points as described above, not limited to the case of using a continuous two points located on both sides of the intersection S _i ^d. For example, the intersections may be discontinuously selected every two points, such as intersections S _i−3 ^d , S _i−1 ^d , S _{i + 1} ^d , and S _{i + 3} ^d .

As shown in FIG. 8, the position of the corresponding point t _i ^d is on a smooth curve, a position where the distance is minimum from the intersection S _i ^d.

  The control device 50 calculates the distance between the corresponding point and the intersection with respect to all intersections in each evaluation section as the feature amount. The length / shortness of the distance between the corresponding point and the intersection corresponds to the degree of unevenness of the work surface after processing.

Controller 50 calculates a characteristic quantity of the intersection on evaluation section D ^d for example by the third calculation method. Figure 9 is an explanatory diagram for explaining a third calculation method for calculating a feature quantity of intersection on evaluation section D ^d.

Controller 50, a line segment connecting for example the calculation of the target intersection S _i ^d (4th intersection) and intersection S _i intersection located on the right of ^d S _i-1 ^d (fifth intersection), the intersection point computing the S _i ^d and the intersection S _i intersections located on the left side of ^d S _{i + 1} ^d formed interior angle Q _i and (sixth intersection) line segment connecting. Controller 50, for each intersection point is calculated as a feature amount a difference 180 degrees and internal angle Q _i. The magnitude of the difference between 180 degrees and the internal angle Q _{i corresponds} to the magnitude of the degree of irregularity of the work surface after processing. Note that an outer angle may be calculated instead of the inner angle.

  Further, the difference between the interior angles may be calculated for two adjacent intersections, and the difference between the interior angles may be used as the feature amount. When the workpiece is machined into a curved surface, the magnitude of the difference between the inner angles corresponds to the magnitude of the degree of irregularity of the workpiece surface after machining.

  FIG. 10 is a conceptual diagram illustrating an example of a color table indicating a relationship between a feature amount and a color. In FIG. 10, “range” indicates a range of the feature amount, and “color” indicates a color corresponding to the feature amount. The storage unit 52 stores a color table, and stores -0.4, -0.2, 0.0, 0.2, and 0.4 as thresholds. For example, “−0.4 to −0.2” in the “range” column indicates that the value exceeds −0.4 and is −0.2 or less.

  The control device 50 stores the color corresponding to the calculated feature amount in the storage unit 52 in association with each intersection. The control device 50 attaches the color stored in the storage unit 52 to each intersection, and displays the intersection on the display unit 8. The operator can change the threshold by operating the operation unit 7.

FIG. 11 is a flowchart illustrating a feature value calculation process performed by the control device 50. CPU51 sets an evaluation section D ^d (see step S1, FIG. 3 and FIG. 4). Next, the CPU 51 creates an intersection table (see FIGS. 5 and 6). Specifically, the CPU 51 sets “1” to a variable i indicating the path number of the reciprocating operation and a variable k indicating the order of instructions constituting the machining program (step S2). Then, the CPU 51 reads the movement route P _k -P _{k + 1} (step S3). Step S1 constitutes a setting unit.

CPU51 determines whether the moving path P _k -P _{k + 1} intersects the evaluation section D ^d (step S4). If the moving path P _k -P _{k + 1} does not intersect the evaluation section D ^d (step S4: NO), CPU51 increments the k (step S8).

If the moving path P _k -P _{k + 1} intersects the evaluation section D ^d (step S4: YES), CPU 51 may evaluate sectional D ^d and the movement path P _k intersection between -P _{k + 1} S _i ^d is already It is determined whether it exists (step S5).

If the intersection point S _i ^d between the evaluation section D ^d and the movement path P _k -P _{k + 1} does not already exist (Step S5: NO), CPU 51 is the intersection table in the storage unit 52 (see FIG. 6), the path number i, the intersection S _i ^d coordinates and stores the moving path P _k -P _{k + 1} in association with each other in (step S7).

If the evaluation section D ^d and the movement path P _k -P _{k + 1} the intersection S _i ^d of already exists (Step S5: YES), CPU51 increments the i (step S6), CPU 51 of the storage unit 52 the intersection table, path number i, the intersection S _i ^d coordinates and movement path P _k -P _{k + 1} the correspondence stored (step S7), and increments k (step S8). Steps S2 to S8 constitute an intersection calculation unit.

After incrementing k, the CPU 51 determines whether k is the last number (step S9). If k is not the final number (step S9: NO), the CPU 51 returns the process to step S3. If k is the final number (Step S9: YES), CPU 51, as described above, for each intersection point S _i ^d, and calculates a feature quantity (step S10, see FIG. 7-9).

  The CPU 51 refers to the color table, acquires a color corresponding to the range to which the calculated feature quantity belongs, and stores the acquired color in the storage unit 52 in association with each intersection (step S11). The CPU 51 attaches the color stored in the storage unit 52 to each intersection, and displays each intersection on the display unit 8 (step S12). Step S10 constitutes a feature amount calculation unit, and step S11 constitutes a generation unit.

  Note that the feature value calculation processing may be executed by an external computer, each intersection may be colored, and each intersection may be displayed on a display unit of the computer.

  In the machine tool according to Embodiment 1, with respect to the intersection between the evaluation cross section and the processing path, a characteristic amount indicating the degree of unevenness of the processed work surface is calculated, and image data corresponding to the calculated characteristic amount is generated. I do. Therefore, the display unit can display the processed work surface based on the generated image data without generating the processed work shape, and the operator can visually recognize a defect on the work surface. it can.

The intersection S _i ^d (first intersection), intersection S _i−1 ^d (second intersection), and intersection S _{i + 1} ^d (third intersection) are calculated, and the calculated first intersection, second intersection, and third intersection are calculated. A second order difference of the first intersection is calculated based on the coordinates of the intersection. Based on the calculated second-order difference, the calculation of the feature amount can be realized.

A curve (for example, a spline curve, a Bezier curve, or a NURBS curve) is set using a plurality of other intersections around one intersection. Projecting a t _i ^d corresponding to the intersection S _i ^d on the curve, it calculates the distance of the corresponding point t _i ^d and one intersection S _i ^d. Based on the calculated distance, the calculation of the feature amount can be realized.

The intersection S _i ^d (4th intersection), the segment calculates the intersection S _i-1 ^d (fifth intersection) and intersection S _{i + 1} ^d (Sixth intersection) connecting the fourth intersection point and fifth point of intersection An angle formed by a line segment connecting the fourth intersection and the sixth intersection is calculated. The calculation of the feature amount can be realized based on the calculated angle.

  When it is determined that the feature value is equal to or less than the threshold value, first image data (for example, blue image data) is generated. When it is determined that the feature value exceeds the threshold value, the feature is generated in a format different from the first image data. The second image data (for example, red image data) indicating the amount is generated. An operator can visually recognize an image formed by the first image data and the second image data and recognize a defect.

(Embodiment 2)
Hereinafter, the present invention will be described with reference to the drawings showing a machine tool according to a second embodiment. FIG. 12 is a plan view schematically showing a machining path and an evaluation section for a workpiece, and FIG. 13 is an explanatory diagram for explaining setting of an evaluation section. Arrows machining path, a dotted line indicates the evaluation section D ^d. Controller 50 sets the evaluation section D ^d with respect to the workpiece. For example, as shown in FIG. 12, when the main shaft 5a moves spirally, the processing path is a path along the spiral direction.

As shown in FIG. 12, the controller 50 sets a plurality of evaluation section D ^d along a direction substantially perpendicular to the machining path. The plurality of evaluation sections are arranged in the circumferential direction of the machining path. The operator instructs in advance that the direction of the machining path is the circumferential direction.

The control device 50 sets the evaluation section, for example, as follows. As shown in FIG. 13, the control device 50 sets a plurality of first reference points O _m (m is a natural number) equidistantly arranged on the outermost peripheral path of the machining path, and sets a plurality of second reference points Om on the innermost peripheral path. to set the reference point L _m. The control device 50 sets a point on the innermost route that is closest to the first reference point O _m as the second reference point L _m .

As shown in FIG. 13, the control device 50 such that the first reference point O _m and the second reference point L _m located on the evaluation section D ^d, and calculates the evaluation section D ^d, sets. The second reference point L _m, because it is closest to the first reference point O _m, evaluation section D ^d becomes substantially perpendicular to the innermost path and outermost path.

The control device 50 determines whether or not the number of command points M _d between the evaluation cross sections D ^d -D ^{d + 1} exceeds the threshold T. If the command number M _d exceeds the threshold T, evaluation section D ^d -D ^d + ¹ of adding new evaluation section D ^{new new} centrally between, all the evaluation section D ^d -D ^d + ¹ between , A process for adding an evaluation section is executed.

Also in the second embodiment, similar to the first embodiment, a feature amount calculation process is executed. In the second embodiment, the evaluation section D ^d -D d + ¹ command number command number M _d existing between such becomes equal, but sets the evaluation section D ^d, the first reference point adjacent O _m -O m + such that the distance between ₁ are equal, it may set the rated cross-section D ^d.

  Among the configurations according to the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 14 is a plan view schematically showing a machining path and an evaluation cross section for a work in a modification. As shown in FIG. 14, when the machining path is spiral, the control device 50 sets the center of the spiral and an angle around the center, and sets a plurality of evaluation sections radially with reference to the center of the spiral. When the number of command points existing between two adjacent evaluation sections exceeds a predetermined threshold, a new evaluation section D ^new is added between the two evaluation sections. It is not necessary to add a new evaluation section.

5a spindle 8 display unit 50 control unit (processing path calculation unit)
51 CPU
52 storage unit 53 RAM

Claims (7)

In a machining path calculation device that calculates a machining path for machining a workpiece based on a plurality of command points indicating a position of a spindle,
A setting unit that sets an evaluation cross section that intersects the machining path,
An intersection calculation unit that calculates a plurality of intersections of the evaluation cross section and the machining path set by the setting unit;
A feature value calculating unit that calculates a feature value indicating a degree of unevenness of the work surface after processing with respect to the plurality of intersections calculated by the intersection calculating unit;
A generation unit that generates image data corresponding to the feature amount calculated by the feature amount calculation unit ,
The feature quantity calculation section, a feature amount of the intersection is an operation of the object, machining path calculation apparatus characterized that you operation using a plurality of other intersections surrounding the intersection said a calculation target. The intersection calculation unit calculates a first intersection, a second intersection having coordinates larger than the coordinates of the first intersection in a direction parallel to the evaluation section, and coordinates smaller than the coordinates of the first intersection in the direction. A coordinate calculation unit for calculating a third intersection having
The feature amount calculation unit includes a second-order difference calculation unit that calculates a second-order difference of the first intersection based on coordinates of the first intersection, the second intersection, and the third intersection. The processing path calculation device according to the above. The intersection calculation unit calculates a plurality of intersections,
The feature amount calculation unit sets a curve using a plurality of other intersections around one intersection, projects a corresponding point corresponding to the one intersection on the set curve, and The machining path calculation device according to claim 1, further comprising a distance calculation unit that calculates a distance of one intersection. The intersection calculation unit calculates a plurality of intersections,
The feature value calculation unit calculates a fourth intersection and a fifth intersection and a sixth intersection located on both sides of the fourth intersection, respectively, and calculates a line segment connecting the fourth intersection and the fifth intersection with the fourth intersection. The machining path calculation device according to claim 1, further comprising an angle calculation unit that calculates an angle formed by a line segment connecting the intersection and the sixth intersection. A determination unit that determines whether the feature amount calculated by the feature amount calculation unit is equal to or less than a preset threshold,
The generating unit, when the determining unit determines that the feature amount calculated by the feature amount calculating unit is equal to or less than the threshold, generates first image data, and the determining unit determines the feature amount calculating unit. When it is determined that the feature value calculated in (1) has exceeded the threshold value, second image data for displaying the feature value in a format different from that of the first image data is generated. The processing path calculation device according to any one of the above. In a machining path calculation method for calculating a machining path for machining a workpiece based on a plurality of command points indicating a position of a spindle,
Set an evaluation cross section that intersects the machining path,
Calculate a plurality of intersections of the set evaluation section and the machining path,
For the calculated plurality of intersections, calculate a feature amount indicating the degree of unevenness of the work surface after processing,
Generate image data corresponding to the calculated feature amount ,
A machining path calculation method , wherein a feature amount of an intersection to be calculated is calculated using a plurality of other intersections around the intersection to be calculated . A computer program executable by a machining path calculation device that calculates a machining path for machining a workpiece based on a plurality of command points indicating a position of a spindle,
In the machining path calculation device,
Set an evaluation cross section that intersects the machining path,
Calculate a plurality of intersections of the set evaluation section and the machining path,
For the calculated plurality of intersections, calculate a feature amount indicating the degree of unevenness of the work surface after processing,
Generate image data corresponding to the calculated feature amount ,
A computer program for executing a process of calculating a characteristic amount of an intersection to be calculated using a plurality of other intersections around the intersection to be calculated .

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