JP2013161111A - Tool path generation system and generation method for thrust work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a tool path for thrust work for the purposes of reducing the number of times of cutting for the thrust work, reducing wear of a tool and prolonging a service life.SOLUTION: A tool path generation system for thrust work includes: means for calculating boundary line information on a body to be cut and a horizontal plane turned to an upper part of the body to be cut from product CAD design drawing information and material CAD information; means for calculating a reference area on the basis of the information on a tool and a work method inputted by a user; means for generating an auxiliary path of a cutting pattern from the information on the boundary line of the body to be cut and a tool radius; means for, when the next cutting point of a cutting tool is assumed, calculating a boundary point of a cutting cross section to execute the thrust work at the cutting point, retrieving a storage part where a calculation formula of a cutting cross sectional area is stored beforehand for each combination pattern of the boundary point, and determining a pertinent calculation formula; means for correcting coordinates of the assumed cutting point using the calculation formula of the cutting cross sectional area, and calculating the next cutting point; and means for adding information of a cutting depth and an avoidance operation to calculated cutting point string data, and generating a thrust work tool path.

Description

  The present invention relates to a system for automatically generating a tool path capable of executing load leveling and thrusting in material processing by a numerically controlled machine tool.

  In order to machine a material with a numerically controlled machine tool, it is necessary to program a numerical control command for controlling the machining operation in advance. It can be generated using CAM (Computer Aided Manufacturing). In the CAM, a tool path is generated from an internal calculation formula based on information such as a processing method designated by an operator, a region to be processed, a rotary cutting tool to be used, and processing conditions. However, even when these setting conditions are the same, the tool paths generated by the tool path calculation method are different, and a difference occurs in the machining time for realizing the required machining accuracy.

  Further, as a machining method of a numerically controlled machine tool, there is a piercing method in which a material is cut while vertically moving a tool such as an end mill or a drill so as to perform drilling. This piercing method is efficient for cutting deep cutting areas. FIG. 3A is an explanatory view of a piercing method shown using a side view. The cutting tool T of the thrusting device descends according to the machining axis while rotating, and the workpiece W is cut by touching the rotating cutting tool T. More specifically, the rotating cutting tool T is lowered to the workpiece W, and when the cutting at one place is finished, the rotating cutting tool T is raised, and the tool T is pulled up to a predetermined position where it does not hit the workpiece. Then, the machining axis is moved in the horizontal direction to the next cutting location, and the cutting tool T is lowered to the workpiece W again and cut. FIG. 3B is an explanatory diagram of the piercing method shown using the top view. The workpiece W is sequentially cut by repeating this while moving the cutting tool T in the order of positions T1, T2, and T3 shown in FIG. 3B. The distance A is a forward step, and the distance B is an overstep. The advance step A is a parameter for designating a plane distance to proceed from one cutting point to the next protruding cutting, and the overstep B is advanced from one line (loop) to the next line (loop). It is a step.

  In the tool path for the piercing process, the machining conditions such as the machining area, the tool to be used, the advance step A, the overstep B, and the cutting pattern for designating the operation pattern of the cutting loop of the tool are set on the CAM setting screen. For example, the tool path for the piercing process can be automatically generated from an internal calculation formula. As a tool path generation method of such a thrusting method, there are methods disclosed in Patent Document 1 and Patent Document 2.

  The generation method described in Patent Document 1 is a method in which the cutting tool T moves at a constant width and a tool feed pitch having a constant width, and cuts the workpiece W that is a processing region. When moving at a constant pitch, if the processing end point of the destination position enters beyond the processing end point of the same position in the previous row, it passes through that position without processing, and the subsequent processing end point is A method is provided in which machining is started from a position that is less than the machining end point at the same position, and then machining is performed while returning in the reverse direction at a fine pitch.

  The machining method described in Patent Document 2 is a method in which the cutting tool T moves at a constant width and a tool feed pitch having a constant width to cut the workpiece W, and the contour of the workpiece is narrow or folded. A processing auxiliary line that connects two points before and after the moving direction of the rotary tool is generated at a position where the rotary tool is formed, and a processing point is arranged at predetermined intervals along the processing auxiliary line.

JP 2002-361513 A JP 2008-126377 A

  In Patent Document 1, when the workpiece W is cut by moving the cutting tool with a constant width and a tool feed pitch having a constant width, the cutting load per one time varies depending on the cutting shape and cutting position of the workpiece. . Specifically, when the cutting load is small, the amount of cutting to be removed by a single thrusting operation is small, so that the cutting efficiency is low. In addition, when the cutting load increases excessively, there is a problem of causing chatter vibration and tool damage. To deal with these problems, it takes time and effort to adjust the cutting speed and to correct the tool path.

  In Patent Document 2, it is possible to avoid the problem of increasing the cutting load by generating an auxiliary line at a location where the cutting load of the workpiece is high and arranging the processing points at predetermined intervals along the auxiliary line. There is a risk that the cutting amount to be removed by the thrusting operation becomes smaller and the efficiency is lowered.

  In the tool path generation method for piercing according to the present invention, the step between a cutting point and the next cutting point is calculated from the reference area while considering the cutting cross-sectional area, and the cutting cross-sectional area per time is brought close to the reference area. In this way, the object is to reduce the number of piercing cuts, reduce tool wear, and improve the service life.

  In order to solve the above-described problems, in the present invention, a machining tool path generation system includes a workpiece that is a machining area based on product CAD design drawing information and material CAD information, and boundary information on a horizontal plane that faces the workpiece. Based on the tool and machining method information input by the user, the reference area is calculated, the boundary line information of the workpiece, and the cutting pattern auxiliary path is generated from the tool radius. Assuming the next cutting point of the means and the cutting tool, the boundary point of the cutting cross section that performs the piercing at the cutting point is calculated, and the calculation formula of the cutting cross sectional area is stored in advance for each boundary point combination pattern The coordinates of the assumed cutting point so that the cutting cross-sectional area is set as the reference area by using the means for searching the storage unit and determining the corresponding calculation formula and the cutting cross-sectional area calculation formula To calculate the next cutting point Means that, in the cutting point sequence data the calculated cutting depth, and configured to include a means for generating information additional to thrust machining tool path avoidance operation.

  In order to solve the above-described problem, in the present invention, the machining tool path generation system designates a cutting point that represents the cutting position of the thrust tool in coordinates on a horizontal plane in the cutting order, and the nth th A calculation formula for calculating the cutting cross-sectional area of the processing tool at the cutting point is configured to include a storage unit that stores in advance corresponding to the combination pattern of the boundary points of the cutting cross-section.

  Further, in order to solve the above problems, in the present invention, in the means for determining the calculation formula of the machining tool path generation system, the boundary point of the cutting cross section is the next cutting point CP (n), and the previous cutting point CP (n). For all cutting points CP (m <n), the intersection of the circle with the tool radius R centered on the next cutting point CP (n) and the boundary of the machining area, and all cutting points CP (m The intersection of the circle of the tool radius R centered at <n) and the boundary of the machining area, and the circle of the tool radius R centered on the cutting point CP (n) in the machining area and all the cutting points CP Extract the intersection point with the circle of the tool radius R centered at (m <n), and within the extracted intersection point, the distance between the intersection point and the next cutting point CP (n) is within the tool radius R And an intersection that satisfies the condition that the distance between the intersection and all the cutting points CP (m <n) is greater than or equal to the tool radius R is selected as a boundary point of the cutting section. It was.

  According to the present invention, the step of the cutting point and the next cutting point can be dynamically adjusted from the reference area, so that the cutting area is brought close to the reference area to reduce the number of cuttings, and the wear of the tool can be reduced and the tool life can be improved. effective.

It is an example of the functional block diagram of the piercing tool path generation system of this invention. FIG. 3 is a flowchart showing a flow of generation processing of a load leveling and boring tool path generation system 100. It is explanatory drawing of the piercing method shown using the side view. It is explanatory drawing of the piercing method shown using the top view. This is an example of product CAD design drawing information, and a rectangular parallelepiped product Sample is composed of a rectangular parallelepiped cutout Box 1 and a cylindrical hole Hole1. It is a figure which shows an example of the raw material CAD information of the raw material mBox which processes the product Sample shown in FIG. FIG. 6 is a diagram showing an example of a cut object CutBox1 that is cut from the material mBox shown in FIG. 5 in order to machine the cutout Box1 of the product Sample shown in FIG. It is a figure which shows an example of the boundary line information of the cut body CutBox1 shown to FIG. 6A. FIG. 6 is a diagram showing an example of a cut object CutHoel1 that is cut to process the cylindrical hole Hoel1 of the product Sample shown in FIG. 4 from the material mBox shown in FIG. It is a figure which shows an example of the boundary line information of the cut body CutHoel1 shown to FIG. 7A. It is a figure which shows an example of a process condition setting screen. It is a figure which shows an example which stored the process condition data set on the process condition setting screen shown to FIG. 8A in the process condition data storage area. It is a figure explaining an example of the calculation method of a reference area. It is a figure which shows an example of the cutting pattern (zigzag pattern) of a thrust tool path. It is a figure which shows an example of the cutting pattern (periphery dependent pattern) of a piercing tool path. It is a figure which shows an example of the offset path | pass of the piercing tool path with respect to the cut body CutBox1 shown to FIG. 6A. It is a figure which shows an example of the auxiliary | assistant path | pass of the cutting pattern (zigzag pattern) of the offset path | pass shown to FIG. 11A. It is a figure which shows an example of the cutting point CP (1), the boundary point of the said cutting point CP (1), and the cutting cross section of the said cutting point. It is a figure which shows an example of the cutting point CP (2), the boundary point of the said cutting point CP (2), and the cutting cross section of the said cutting point. It is a figure which shows an example of the cutting point CP (n), the boundary point of the said cutting point CP (n), and the cutting cross section of the said cutting point. It is a figure which shows an example of the processing flow which calculates the boundary point of the cutting cross section of Nth cutting point CP (N). It is a figure which shows the first half part of the processing flow which calculates a cutting point from a reference area using the calculation formula of a cutting cross section. It is a figure which shows the latter half part of the processing flow which calculates a cutting point from a reference area using the calculation formula of a cutting cross section. An example of the image figure of the cutting point produced | generated by the process of FIG. 14 is shown. An example of an image diagram of a tool path for piercing is shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a functional configuration diagram of a machining tool path generation system 100 in which the automatic machining tool path generation function of the present invention is mounted on a three-dimensional CAM apparatus. The butt tool path generation system 100 includes a calculation unit 101, a storage unit 102, an input unit 103, an output unit 104, and a communication unit 105. Further, the communication unit 105 and the network 150 are connected to the three-dimensional CAD device 130 and the NC processing machine 140.

  In addition to the conventional three-dimensional CAM unit 111 that performs processing up to creation of an NC program for processing using shape data created by CAD as input data, the arithmetic unit 101 obtains shape information of parts (products) from the three-dimensional CAD device 130. The product CAD design drawing information and the material CAD information including the material shape information are inputted and stored in the product CAD design drawing information storage area 123 and the material CAD information storage area 124, and the product CAD design drawing A workpiece calculation unit 112 that calculates shape information of the workpiece from the information and the material CAD information, and a machining condition setting screen is displayed on the output unit 104, and tool information and a machining method are read from the user via the input unit 103. Machining condition acquisition unit 116, cutting pattern auxiliary path generation unit 114 that generates a cutting pattern auxiliary path by the tool information and processing method acquired by the processing condition acquisition unit 116, and the processing conditions A reference area calculation unit 115 that calculates a reference area according to the machining conditions acquired by the acquisition unit 116, and a cutting section boundary line information of a cutting body boundary line and a cutting point calculated by the cutting body calculation unit 112 The area calculation formula determination unit 117 that determines the area calculation formula for calculating the cutting area of the next cutting point using the area calculation formula, and the reference area calculation unit using the area calculation formula determined by the area calculation formula determination unit 117 The cutting point calculation unit 118 that calculates the cutting point of the piercing based on the reference area calculated in 115, and the tool path generation that adds the information of the cutting depth and the avoidance operation to the cutting point information and generates the tool path of the piercing Unit 113.

  The storage unit 102 includes a machining condition data storage area 120, an area calculation formula storage area 121, a machining apparatus condition data storage area 122, a product CAD design drawing information storage area 123, a material CAD information storage area 124, and a workpiece information storage area 125. A tool path data storage area 126 and an NC data storage area 127.

  FIG. 2 shows a flow of tool path generation processing of the tooling tool path generation system 100. The tool path acquires the shape information of the workpiece (machining area) from the product CAD design drawing information and material CAD information, reads the machining conditions such as the tool and machining method set on the machining condition setting screen, and After the auxiliary path is generated, the load is calculated with a uniform load tool tool with a uniform cutting cross-sectional area based on the reference area calculated by the reference area calculation unit 115. This flow is started when the user is requested to perform a process for calculating the tooling tool path via the input unit 103.

  Details of the tool path automatic calculation processing will be described below with reference to FIG.

  First, product (part) shape information is obtained from product CAD design drawing information, and material shape information is obtained from material CAD information (S100). In general, product CAD design drawing information is modeled in a three-dimensional space by giving geometric information of each part of a product (part) and non-geometric information associated therewith by a user. The material CAD information is defined by numerical input of the material block shape.

Next, shape information of the workpiece (processing area) is calculated from the product (part) shape information and material shape information acquired in S100 (S200).
Next, information on machining conditions such as the tool and machining method set on the machining condition setting screen is read from the machining condition data storage area 120 (S300), and the recommended cutting efficiency for each tool using the read machining conditions. A reference area having a high cutting cross-sectional area is calculated (S400).
Then, an auxiliary path of the cutting pattern is generated from the shape information of the workpiece acquired in S200 and the processing conditions acquired in S300 (S500).
Next, a boundary point of the cutting cross section is calculated, a calculation formula for the cutting cross section is determined, and an area calculation formula for the cutting cross section is read from the area calculation formula storage area 121 (S600).
Then, the cutting point calculation unit 118 uses the reference area calculated in S400 as the cutting cross-sectional area of the cutting point, and calculates the cutting point from the area calculation formula read in S600 (S700).
Next, in the cutting point information calculated in S700, information on the cutting depth and avoidance operation of the cutting point calculated from the shape information of the workpiece calculated in S200 and the processing conditions read in S400 In addition, the tool path generation unit 113 automatically generates a machining tool path (S800).
Finally, the tool path generation unit 113 stores the generated tool path data in the tool path data storage area 126 and outputs it to the output unit 104 (S900). The tool path data is output to a file, display, paper or the like.

  A tool path generation method for a rectangular parallelepiped Sample in which a rectangular parallelepiped cutout Box1 and a cylindrical hole Hole1 are formed will be described below with reference to FIGS.

(1) Acquire model shape information from product CAD design drawing information and material CAD information (S100)
FIG. 4 shows an example of product CAD design drawing information. The product Sample shown in FIG. 4 includes a set operation of a rectangular parallelepiped box, a rectangular parallelepiped box 1, and a cylindrical hole Hole1. Product CAD design drawing information includes information on the basic solid Box, Box1, and Hole1 that make up the Product Sample, and information on straight lines, planes, curves, etc. for shape representation. Obtained by the obtaining unit 110. The CAD information acquired from the product CAD design drawing information of the product Sample shown in FIG. 4 includes the following information.

(A) There are three horizontal surfaces facing upward. f6 is the surface of Box, f15 is the bottom of vertical rectangular hole Box1, and f21 is the bottom of vertical circular hole Hole1.
(B) The basic three-dimensional box is a space limited by three pairs of parallel planes f1 to f6 that have q1 to q8 as vertices.
(C) The basic three-dimensional Box 1 is a space limited by three pairs of parallel planes f11 to f16 having q11 to q18 as vertices.
(D) the primitive Hole1 _{is, q21 (x 0, y 0} , z 01), a cylinder having a radius r ₀ to q22 the _{(x 0, y 0, z} 02) axis.
(Equation 1)
f (x, y) = r ₀ ² − (x−x ₀ ) ² − (y−y ₀ ) ² > = 0
z ₀₂ <= z <= z ₀₁
FIG. 5 shows an example of a material mBox for processing the part Sample shown in FIG. The material mBox defined in FIG. 5 is composed of a basic solid Box. The material information includes information on the basic solid box constituting the processing material and information such as straight lines, planes, and curves of shape expression, and the shape information acquisition unit 110 acquires expression expressions of these shapes. The material information acquired from the material CAD information storage area 124 for processing the product Sample shown in FIG. 4 includes the following information.
(A) There is one horizontal plane facing upward, which is the surface of the Box.
(B) The basic three-dimensional box is a space limited by three pairs of parallel planes f1 to f6 that have q1 to q8 as vertices.

(2) Acquisition of workpiece shape and boundary information (S200)
FIG. 6A shows an example of a cut body CutBox1 that is cut from the material mBox shown in FIG. 5 in order to machine the cutout Box1 of the product Sample shown in FIG. The information of the cut object CutBox1 includes information such as straight lines, planes, and curves of the shape expression of the cut object CutBox1, and the work object calculation unit 112 acquires the expression of each shape. FIG. 6B shows an example in which the boundary line information of the cut object CutBox1 shown in FIG. 6A is calculated.
(A) There is one horizontal plane facing upward, which is the surface of CutBox1, and is composed of boundary lines Line1 to Line4. Since the boundary line Line1 and the material boundary line coincide, the outer space does not interfere. Since the boundary lines Line2 to Line4 are boundary lines between the material and the product, the outer space interferes with the tool.
(B) The cut object CutBox1 is a space limited by three pairs of mutually parallel planes f11 to f16 with the vertices at q11 to q18. Since the planes f11 and f16 coincide with the boundary surface of the material, the space outside the planes f11 and f16 does not interfere with the tool. The planes f12 to f15 are boundary surfaces between the material and the product, and the outer space interferes with the tool.

FIG. 7A shows an example of a cut object CutHole1 cut from the material mBox shown in FIG. 5 in order to machine the cylindrical hole Hole1 of the product Sample shown in FIG. FIG. 7B shows an example in which the boundary line information of the cut object CutHole1 shown in FIG. 7A is calculated.
(A) There is one horizontal plane facing upward. f21 is the surface of CutHole1, and the boundary line Line21 is formed. Since the boundary line 21 is a boundary line between the material and the product, the outer space interferes with the tool.

(3) Acquisition of machining conditions set on the machining condition setting screen (S300)
An example of the processing condition setting screen 180 is shown in FIG. 8A. In the machining condition setting screen 180 shown in FIG. 8, the tool cutting diameter D1, cutting effective blade length FL, tool length L1, etc. are set, and the tool holder diameter D2 supporting the tool and the holder length are set. Information such as L2 and the tepper angle of the holder is set, and the user can set the cutting pattern of the processing method, the forward step A, and the overstep B. The user inputs the forward step A and the overstep B in consideration of the information on the machining conditions recommended by the tool manufacturer along with the selection of the tool.
The machining condition acquisition unit 116 acquires the tool information and the machining method set on the machining condition setting screen 180 and stores them in the machining condition data storage area 120. FIG. 8B shows an example of the format stored in the machining condition data storage area 120 of the machining condition data set on the machining condition setting screen 180 of FIG. 8A.

(4) Calculation of standard area (S400)
A method for calculating the reference area will be described with reference to FIG. The formula for calculating the reference area is shown in the following formula 2. Here, Sa21 is an arcuate area centering on the point cp2 shown in FIG. Sa22 is an area of an arcuate shape with the points P2 and P5 of the circle centering on cp2 shown in FIG. Sa11 is an arcuate area centered on the point cp1 shown in FIG. 9 and ends at points P3 and P5. St1 is an area of a triangle whose ends are points P2, P3, and P5 shown in FIG. . The reference area Sc is calculated by the reference area calculation unit 115 from the advance step A, the overstep B, and the tool radius R acquired by the machining condition acquisition unit 116 using Equations 2 to 8.
(Equation 2) Sc = Sa21 − Sa22 − Sa11 − St1
(Equation 3) Sa21 = (1/2) ・ R ²・ ((C1) −sin (C1))
(Equation 4) Sa22 = Sa11 = (1/2) · R ² · ((C2) −sin (C2))
(Equation 5) St1 = 2 ・ R ²・ (sin ((C2) / 2)) ²・ sin (2 ・ (C3))
(Equation 6) C1 = π−2 · sin ⁻¹ (1-B / R)
(Equation 7) C2 = cos ⁻¹ (A / (2 ・ R)) − sin ⁻¹ (1−B / R)
(Equation 8) C3 = π / 2 − (C2) / 2 − sin ⁻¹ (1−B / R)

(5) Generate auxiliary path of cutting pattern (S500)
The cutting pattern auxiliary path generation unit 114 generates the cutting pattern auxiliary path from the information on the boundary line of the workpiece calculated by the workpiece calculation unit 112 and the tool radius acquired by the machining condition acquisition unit 116. To do.

10A and 10B show two typical types of cutting patterns for piercing. The plane path for controlling the cutting interval for thrusting is controlled by the forward step A, the overstep B, and the cutting pattern. Here, the forward step A is a parameter for designating a plane distance to proceed from one cutting point to the next cutting, and the overstep B is from one line (loop) to the next line (loop). It is a step between lines that proceed to machining. The cutting pattern is a parameter that specifies a cutting operation pattern of the tool, and includes a zigzag pattern that advances along a parallel line, an outer peripheral dependent pattern that advances along a machining area, and the like.
FIG. 10A shows an example of a zigzag pattern of a tooling tool path. The zigzag pattern is a linear reciprocating feed cutting pattern in which a tool path is generated along a straight line in one direction and then a tool path is generated along a parallel straight line in the opposite direction.
FIG. 10B shows an example of an outer periphery dependent pattern of a piercing tool path. The outer periphery dependent pattern is a cutting pattern that generates a path along the contour of the machining area inward after generating a path along the outermost outline of the machining area.

  FIG. 11A shows an example of an offset path in the plane f16 of the cut object CutBox1 shown in FIG. 6A. The offset path is a locus of the center point of the tool that touches the boundary line of the machining area, and is generated by the following method. First, an offset PassOF1 is generated by offsetting the tool radius outward from the boundary line Line1 that does not contact the non-machined area. Next, an offset pass PassOF2, PassOF3, and PassOF4 is generated by offsetting the tool radius inward from the boundary lines Line2, Line3, and Line4 in contact with the non-machining region.

  FIG. 11B shows an example of auxiliary path generation of a zigzag pattern in the offset paths PassOF1 to PassOF4 shown in FIG. 11A. From the offset path PassOF1 of the boundary line Line1 that does not touch the non-machined area to the farthest offset path PassOF3, a straight line in the reciprocating direction is generated at the interval of the overstep B acquired by the machining condition acquisition unit 116, and the auxiliary pass PassP1 of the cutting pattern ~ Generate PassP5. In the example of FIG. 11B, the interval from the offset pass PassOF1 to the auxiliary passes PassP1 to PassP4 is common to B, but the interval between the auxiliary passes PassP4 and PassP5 is as short as B1.

(6) The boundary point of the cut cross section is calculated, and the calculation formula of the cut cross section is determined (S600).
The tool path creation process of the thrusting device is mainly to sequentially determine the cutting point CP (n) represented by the XY coordinates on the horizontal plane for moving and positioning the cutting tool to the processing position. The cutting point CP (n) represents the XY coordinate position of the rotation center axis of the cutting tool, and at each cutting point CP (n) position, the cutting tool is lowered to a desired depth while rotating, and thrusting is performed. Will be. The cutting cross-sectional area of piercing at the n-th cutting point CP (n) is all cutting points before the cutting point CP (n−1), the tool half R, the forward step A, and the overstep B. Calculated based on

  When calculating the cutting cross-sectional area of piercing at the cutting point CP (n), attention is paid to the boundary point of the cutting cross-section. A method for determining the area of the cutting cross-sectional area will be described below using a typical pattern example shown in FIG.

FIG. 12A is an example of calculating the cutting cross-sectional area at the first cutting point CP (1) moved by the overstep B1 from the start point CP (0) on the offset path PassOF1 of the machining area. The boundary points P1 and P2 on the arc of radius R centering on the first cutting point CP (1) are shown. Since the boundary points P1 and P2 are the intersections of the arc of radius R centered on the cutting point CP (1) and the boundary line Line1 of the machining area, the cutting section S1 of the cutting point CP (1) is the cutting point CP ( It is an arc shape surrounded by an arc centered at 1) and the boundary line Line1, and the area calculation formula is as follows.
(Equation 9) S1 = (1/2) · R ² · ((C1) −sin (C1))
(Equation 10) C1 = π−2 · sin− ¹ (1-B1 / R)
FIG. 12B calculates the cutting cross-sectional area at the second cutting point CP (2) moved by over step B2 (may be referred to as advance step B2) following the cutting at the cutting point CP (1) in FIG. 12A. This is an example.
Boundary points P3 and P4 on an arc having a radius R centered on the second cutting point CP (2) are shown. Boundary points P3 and P4 are the intersections of the arc of radius R centered on the cutting point CP (2) and the boundary line Line1 of the machining area, and the boundary points P1 and P2 are centered on the cutting point CP (1). The cutting cross section S2 at the cutting point CP (2) is centered on the cutting point CP (1) whose end points are the boundary points P1 and P2 because the arc of the radius R and the boundary line Line1 of the machining area are the intersections. Arc, boundary line Line1 with boundary points P2 and P4 as endpoints, arc centered at cutting point CP (2) with boundary points P4 and P3 as endpoints, and boundary line with boundary points P3 and P1 as endpoints The shape is surrounded by Line1, and the area calculation formula is as follows.
(Equation 11) S2 = (1/2) ・ R ²・ ((C2) −sin (C2)) − S1
(Equation 12) C2 = π−2 · sin− ¹ (1- (B1 + B2) / R)
FIG. 12C calculates the cutting cross-sectional area Sn at the next nth cutting point CP (n) moved by the forward step An and the overstep Bn after piercing at the mth cutting point CP (m). This is an example.
Boundary points Pn2 and Pn3 on the arc of radius R centered on the nth cutting point CP (n) and a boundary point Pm2 on the arc of radius R centered on the mth cutting point CP (m) Indicates. The boundary point Pn2 is the intersection of a circle with a radius R centered on the cutting point CP (n) and the boundary line Line1 of the machining area, and the intersection point Pn3 is a radius R centered on the cutting point CP (n). Is the intersection of the circle of radius R with the cutting point CP (m) as the center point, and the boundary point Pm2 is the intersection of the circle with the radius R centering on the cutting point CP (m) and the boundary line Line1 Therefore, the cutting cross section at the cutting point CP (n) has an arc centered at the cutting point CP (n) with the boundary points Pn2 and Pn3 as end points, and a cutting point CP (m with the boundary points Pn3 and Pm2 as end points. ) And a boundary line Line1 with the boundary points Pm2 and Pn2 as end points, and the area calculation formula is as follows.
(Equation 13) Sn = San1 − San2 − Sam1− Str
(Expression 14) San1 = (1/2) · R ² · ((π−2 · (C3)) − sin (π−2 · (C3))
(Equation 15) San2 = (1/2) ・ R ²・ ((C5) −sin (C5))
(Equation 16) Sam1 = (1/2) ・ R ²・ ((C6) −sin (C6))
(Expression 17) Str = 2 · R ² · sin ((C6) / 2) · sin ((C5) / 2) · sin ((C6) / 2 + (C5) / 2 + (C4))
(Equation 18) C1 = sin ⁻¹ (Lm / R)
(Equation 19) C3 = sin− ¹ ((Lm / R) − (An · sin (C) / R) · (sin (C2) / sin (C + (C2)))
(Expression 20) C4 = 2 · sin ⁻¹ (An · (sin (C) / (2 · R)) · sin (C + (C2)))
(Equation 21) C5 = π / 2 − (C4) / 2 − (C3) − (C2)
(Equation 22) C6 = π / 2 − (C4) / 2 − (C1) + (C2)
(Equation 23) Bn = (Lm−Ln) / sin (C)

12A, 12B, and 12C are calculated in advance in the area calculation formula storage area 121 together with the pattern of the boundary points of the cutting cross section. In addition to the above three examples, an area calculation formula is registered by using a pattern of how the boundary points of the cut section appear.
FIG. 13 shows an example of a processing flow for calculating the boundary point of the cutting section of the Nth cutting point CP (N).

First, in step S601, a cutting point CP (N) is acquired, and a variable n = N and an intersection number k = 1 are set.
In step S602, the coordinates of the intersection point P (k) between the circle of radius R centering on the cutting point CP (n) and the boundary line of the machining area are acquired and recorded. The intersection number k is incremented with recording.
In step S603, it is determined whether there is a cutting point CP (n−1) that is younger than the cutting point CP (n). When there is a younger order cutting point, the process proceeds to step S604, and when there is no younger order cutting point, the process proceeds to step S606.
In step S604, cutting points CP (n) in ascending order are acquired.
In step S605, the coordinates of the intersection point P (k) of the circle of radius R centered on the cutting point CP (N) and the circle of radius R centered on the cutting point CP (n) in the machining area Get and record. The intersection number k is incremented with recording. Thereafter, the process proceeds to step S602.

In step S606, an intersection number k = 0 is set, and an intersection point that is a boundary point of the cutting section at the cutting point CP (N) is extracted from the intersection point P (k) calculated in the step in the subsequent steps.
In step S607, k = k + 1; m = N-1.
In step S608, the distance DkN between the intersection point P (k) and the cutting point CP (N) is calculated. When DkN is larger than the tool half R, the intersection point P (k) is excluded from the boundary point and the process proceeds to step S612. . If DkN is within the tool half R, the process moves to step S609.
Next, in step S609, the distance Dkm between the intersection point P (k) and the cutting point CP (m) in the order lower than the cutting point CP (N) is calculated. If it is determined that processing has been performed), the intersection point P (k) is excluded from the boundary points, and the process proceeds to step S612. If Dkm is equal to or greater than the tool half R, the process moves to step S610, and the determination in step S609 is repeated for all cutting points CP (m) in the order lower than the cutting point CP (N).
In step S611, the intersection point P (k) is set as the boundary point of the cutting section at the cutting point CP (N).
In step S612, the above steps S607 to S611 are repeated for all the intersection points P (k) to determine the boundary point of the cutting section at the cutting point CP (N).
Next, in step S613, the area calculation formula storage region 121 is searched based on the feature of the boundary point of the cutting section at the cutting point CP (N), and the calculation formula of the cutting cross section is determined.

(7) The cutting point is calculated from the reference area using the calculation formula of the cutting section (S700).
14A and 14B show an example of a processing flow for calculating the cutting point CP (n) of the thrust tool path.

First, in step S701, the auxiliary passes Pass (1) to Pass (J) of the cutting pattern generated in step S500 are read, and the variable j = 1 is set.
In step S702, the start point cutting point CP (0) is read and the variable n = 0 is set.

Next, in step S703, the variable n is incremented,
In step S704, the next cutting point CP (n) is assumed at a specified step interval in accordance with a conventional tool path generation method for piercing.
In step S705, the boundary point of the cut cross section of the assumed cutting point CP (n) is obtained by the processing in step S600 shown in FIG. 13, and the area calculation formula is determined.

Next, in step S706, the determined area calculation formula is read from the area calculation formula storage area 121, and Bn where the cutting cross sectional area Sn becomes the reference area Sc calculated in S400 is calculated by the inverse analysis method.
In step S707, the cutting point CP (n) (x (n), y (n)) is corrected by Bn.
In step S708, if Bn calculated in step S706 is smaller than the auxiliary pass over step B (j), the cutting point CP (n) is output in step S709, and then the process proceeds to step S703 to increment the variable n. Then, the next cutting point CP (n) is calculated. In step S708, if Bn> = B (j) calculated in step S706, the process proceeds to step S710.

In step S710, Bn and B (j + 1) are compared. If Bn> B (j + 1), y (n) = y (n) − (Bn−B (j + 1)) is adjusted (step S711)
In step S712, the cutting point CP (n) (x (n), y (n)) is output.

In step S713, a distance D (n) from the cutting point CP (n) to the end point of the auxiliary pass Pass (j) is calculated.
Next, in step S714, n is incremented, and in step S715, the cutting point CP (n) of the next step n = n + 1 is set at the specified step interval in accordance with the conventional tooling path generation method for piercing. Assuming x (n) = x (n−1) + A; y (n) = y (n−1). Here, the forward step A is a positive value when the direction of the auxiliary pass Pass (j) is the same as the x-axis, and is negative when the direction of the auxiliary pass Pass (j) is the opposite direction to the x-axis. Take the value of
In step S716, the boundary point of the assumed cutting point CP (n) in the cut section is obtained by the process in step S600 shown in FIG. 13, and the area calculation formula is determined.
In step S717, using the area calculation formula read from the area calculation formula storage area 121, Bn = B (n−1) and Sn = Sc are substituted to calculate the forward step An of the cutting point CP (n). .

In step S718, the distance D (n−1) from the cutting point CP (n−1) calculated in step S713 to the end point of the auxiliary pass Pass (j), and the An calculated in step S717. If D (n−1)> An, x (n) = x (n−1), y (n) = y (n) is performed in step S719, and step S720 Then, the cutting point CP (n) (x (n), y (n)) is output, and the above steps S713 to S720 are repeated until D (n−1) <= An.
If D (n−1) <= An in step S718, the process proceeds to step S721.

In step S721, the forward step An = D (n−1) of the cutting point CP (n) is set, and Bn where the cutting cross-sectional area is equal to the reference area Sc calculated in S400 is calculated by the inverse analysis method.
In step S722, the cutting point CP (n) is corrected to x (n) = x (n−1) + D (n−1) and y (n) = y (n−1) + Bn.
Next, in step S723, a distance D (nJ) between the cutting point CP (n) and the auxiliary pass Pass (J) is calculated.

In step S724, if the distance D (nJ) is smaller than the tool radius R, the process proceeds to step S726. If the distance D (nJ) is greater than or equal to the tool radius R, the process proceeds to step S725.
In step S725, y (n) = y (n) − (R−D (nJ)) is corrected.
In step S726, the cutting point CP (n) is output.
In step S727, j = j + 1 is set, a cutting point of the next auxiliary pass Pass (j) is generated, and steps S703 to S727 are repeated until the final auxiliary pass Pass (J) is completed.
FIG. 15 shows an example of an image diagram of cutting points (indicated by black circles) generated by the processing of the flowcharts of FIGS. 14A and 14B.

(8) A cutting tool path is generated by adding information on the cutting depth and avoidance operation to the cutting point (S800).
FIG. 16 shows an example of an image diagram of the generated tool path for butt machining. The tool path for piercing is a plane path that controls the distance and coordinates between the cutting points in the clearance plane perpendicular to the tool axis, an axial path that moves vertically up and down along the tool axis direction, and cutting from the cutting end point. It consists of a retract path for controlling the retract distance and retract angle for retreating out of the plane. First, on the clearance plane, the tool is moved to the cutting position / cutting point CP (n) (Pass 1). Next, the tool is moved from the clearance plane to the start point of the cutting pass (Pass2), and the material is cut vertically to the cutting end point (Pass3). Then, the retraction operation is performed from the end point of cutting and retreats to the outside of the cutting surface (Pass4). Finally, return to the clearance plane along the tool axis from the retracted retract point (Pass5).

The tool path generation unit 113 of the present invention calculates the cutting point CP (n) and stores it in the tool path data storage area 126. Thereafter, the three-dimensional CAM unit 111 reads the cutting point CP (n) data from the tool path data storage area 126 and the information input on the machining condition setting screen 180 from the machining condition data storage area 120, and The apparatus data and information related to control are read from the machining apparatus condition data storage area 122, and the above-mentioned tool path auxiliary information is generated by the current CAM tool. Then, NC data of the piercing NC device 140 is created and stored in the NC data storage area 127.
The created NC data is downloaded to the NC processing machine 140 via the communication unit 105.
The embodiment of the present invention has been described above.

100 ... Veneer tool path generation system
101 ... Calculation unit
102 ... Memory unit
103 ... Input section
104 ... Output section
105 ... Communication Department
110… Shape information acquisition unit
111… 3D CAM
112 ... Workpiece calculation unit
113 ... Tool path generator
114 ... Cutting pattern auxiliary path generator
115: Reference area calculation unit
116 ... Machining condition acquisition unit
117 ... Determination part of area calculation formula
118 ... Cutting point calculator
120 ... Machining condition data storage area
121 ... Area calculation formula storage area
122 ... Machining equipment condition data storage area
123… Product CAD design drawing information storage area
124: Material CAD information storage area
125 ... Workpiece information storage area
126… Tool path data storage area
127 ... NC data storage area
130… 3D CAD equipment
140 ... NC processing machine
150 ... Network
180 ... Machining condition setting screen

Claims (8)

A workpiece that is a machining area based on product CAD design drawing information and material CAD information, and means for calculating boundary information on a horizontal plane facing the workpiece,
Means for calculating a reference area based on information of a tool and a processing method input by a user;
Information on the boundary line of the workpiece and means for generating an auxiliary path of the cutting pattern from the tool radius;
When the next cutting point of the cutting tool is assumed, the boundary point of the cutting cross section that performs the piercing process at the cutting point is calculated, and the calculation formula of the cutting cross sectional area is stored in advance for each combination pattern of the boundary points Means for searching the storage unit and determining a corresponding calculation formula;
Means for calculating the next cutting point by correcting the coordinates of the assumed cutting point so that the cutting cross-sectional area is the reference area, using the calculation formula of the cutting cross-sectional area;
Means for adding a cutting depth and avoidance operation information to the calculated cutting point sequence data to generate a piercing tool path;
A veneering tool path generation system characterized by comprising:   The means for calculating the reference area calculates the reference cutting area using advance step A as the cutting depth of the tool, overstep B as the cutting width, and tool radius R from preset machining condition data. The piercing tool path generation system according to claim 1.   Specify the cutting point that represents the cutting position of the thrust tool with the coordinates on the horizontal plane in the cutting order, and calculate the cutting cross section of the cutting tool at the nth cutting point by The stab tool path generation system according to claim 1, further comprising a storage unit that stores in advance corresponding to a combination pattern of boundary points.   The boundary point of the cut section is a tool having the next cutting point CP (n) as a center point with respect to the next cutting point CP (n) and all the cutting points CP (m <n) before the next cutting point CP (n). The intersection of the circle of radius R and the boundary of the machining area, and the intersection of the circle of tool radius R centered at all cutting points CP (m <n) and the boundary of the machining area, and within the machining area Extract the intersection of the circle with the tool radius R centered on the cutting point CP (n) and the circle with the tool radius R centered on all the cutting points CP (m <n). In this condition, the distance between the intersection point and the next cutting point CP (n) is within the tool radius R, and the distances between the intersection point and all the cutting points CP (m <n) are not less than the tool radius R. The piercing tool path generation system according to claim 1 or 3, wherein an intersection point is selected as a boundary point of the cutting section. A tool path generation method for generating cutting point sequence data represented by coordinates on a horizontal plane for driving a thrust NC apparatus by a computer,
A process of calculating boundary information of a work body which is a machining area from product CAD design drawing information and material CAD information, and a horizontal plane facing the work body;
A step of calculating a reference area based on information of a tool and a processing method input by a user;
A step of generating an auxiliary path of the cutting pattern from the information on the boundary line of the workpiece and the tool radius;
When the next cutting point of the cutting tool is assumed, the boundary point of the cutting cross section that performs the piercing process at the cutting point is calculated, and the calculation formula of the cutting cross sectional area is stored in advance for each combination pattern of the boundary points Searching the storage unit and determining a corresponding calculation formula;
Using the calculation formula of the cutting cross-sectional area, correcting the coordinates of the assumed cutting point so that the cutting cross-sectional area is the reference area, and calculating the next cutting point;
And a step of generating a tooling tool path by adding information of a cutting depth and an avoidance operation to the calculated cutting point sequence data.   In the step of calculating the reference area, the reference cutting area is calculated using advance step A as the cutting depth of the tool, overstep B as the cutting width, and tool radius R from preset machining condition data. The piercing tool path generation method according to claim 5.   Specify the cutting point that represents the cutting position of the thrust tool with the coordinates on the horizontal plane in the cutting order, and calculate the cutting cross section of the cutting tool at the nth cutting point by 6. The piercing tool path generation method according to claim 5, further comprising a step of storing in a storage unit in advance in association with a combination pattern of boundary points.   The boundary point of the cut section is a tool having the next cutting point CP (n) as a center point with respect to the next cutting point CP (n) and all the cutting points CP (m <n) before the next cutting point CP (n). The intersection of the circle of radius R and the boundary of the machining area, and the intersection of the circle of tool radius R centered at all cutting points CP (m <n) and the boundary of the machining area, and within the machining area Extract the intersection of the circle with the tool radius R centered on the cutting point CP (n) and the circle with the tool radius R centered on all the cutting points CP (m <n). In this condition, the distance between the intersection point and the next cutting point CP (n) is within the tool radius R, and the distances between the intersection point and all the cutting points CP (m <n) are not less than the tool radius R. 8. The piercing tool path generation method according to claim 5, wherein the calculation is performed by selecting an intersection as a boundary point of the cutting section.

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