JP4700369B2 - CAM device, tool path creation method, and tool path creation program - Google Patents

Description

  The present invention relates to a CAM device for a multi-axis numerical controller.

  Simultaneous multi-axis control NC (Numerical Control) processing machine has three linear movement axes and at least one rotational movement axis, and has the feature of cutting complex shapes without changing the setup, but CAD (Computer Aided Design) Operation is difficult without the support of a device or a CAM (Computer Aided Manufacturing) device. Here, the CAM device is based on data (tool track data) of a tool path (also called a tool path, CL (Cutter Location)) that is a path that the cutting tool follows during cutting, based on the shape data created by the CAD apparatus. Has the role of creating

  At this time, the tool trajectory data created by the CAM device represents the moving direction and distance of the cutting tool tip calculated in the machining path direction, that is, a line connecting a certain tool path point and the next tool path point as a vector. It consists of tool tip position vector data (hereinafter referred to as tool tip position vector) and tool spindle direction vector data (hereinafter referred to as tool spindle direction vector) indicating the spindle direction of the cutting tool. Here, the tool path point is a point recorded as computer data among points on the tool trajectory. First, the CAM device creates a tool spindle direction vector so as to be inclined at a certain angle with respect to a normal vector of the surface of a workpiece that is a workpiece (for example, Non-Patent Document 1). Next, the CAM device creates a tool tip position vector when the cutting tool is placed in contact with the curved surface of the workpiece surface according to the tool spindle direction vector. Generally, the tool spindle direction vector is set to be tilted forward with respect to the traveling direction of the cutting tool.

FIG. 9 is a diagram illustrating a state in which the tool spindle direction vector is set to be tilted forward with respect to the traveling direction of the cutting tool. The definition of the tool spindle direction vector will be described later with reference to FIG. As shown in FIG. 9, the tool spindle direction is such that the cutting tool T is inclined forward by a fixed angle θ ′ with respect to the normal vector 103 on the surface of the workpiece W ′ and the traveling direction 101 of the cutting tool T. Vector 104 ' is set.

  Further, Non-Patent Document 2 discloses an inclination angle and processing when a cutting tool having a spherical shape with a rotating cutting tool (hereinafter referred to as a ball end mill) is inclined at a predetermined angle to cut a rectangular parallelepiped workpiece. Studies that examine the relationship of accuracy are disclosed. As a result, it was confirmed that the surface roughness was close to the theoretical value and good machining accuracy was obtained when the cutting tool was used in a state where it was tilted backward with respect to the direction of travel (hereinafter referred to as thrusting). ing.

  Furthermore, in Patent Document 1, a plurality of machining points that are points on the tool trajectory are provided on the surface of a workpiece having a plurality of curves, adjacent machining points are connected by a straight line, and the shape of the straight line and the workpiece are compared. A technique is disclosed in which when at least a part of a workpiece is closer to the machining surface than the straight line, it is determined that interference between the cutting tool and the workpiece occurs, and the inclination of the cutting tool is changed.

Further, in Patent Document 2, in the piercing process by sending the cutting tool in the axial direction, the direction in which the rotary blade moves away from the workpiece in order to suppress vibration (chatter) generated near the stroke end, that is, at the end of the machining, In particular, a technique is disclosed in which a cutting tool is moved away from a work in an arc shape.
Nikkei CG edited "Basic knowledge of CAD" Nikkei Business Publications, August 1994, pp.266-267 Kazuyuki Oyama, Koichi Morishige, Yoshimi Takeuchi, “Study on Inclined Machining of Ball End Mill for Improvement of Surface Accuracy” The Japan Society for Precision Engineering, 2000.10.7-9, Academic Lecture Meeting of the Japan Society for Precision Engineering pp. 372 JP-A-8-305427 (paragraphs 0051 to 0055, FIGS. 10 and 11) Japanese Patent Laid-Open No. 10-86009 (Claim 1, Claim 2, FIG. 1)

  However, the above-described method of setting the tool spindle direction vector by tilting forward with respect to the traveling direction of the cutting tool is performed in order to realize high-efficiency cutting processing (hereinafter referred to as pick feed amount). ) Increase, cutting feed rate increase, cutting depth increase, etc., there is a problem that cutting resistance increases, causing vibrations and workpiece deformation.

In addition, the experiment disclosed in Non-Patent Document 2 is intended for a case where the shape after cutting becomes a flat surface, and does not assume a case where the shape after cutting becomes a curved surface, and the target cutting There was a problem that the tool was only a ball end mill and not other cutting tools.
In addition, although the thrusting has been used conventionally, the thrusting is used only for roughing, and the thrusting is not applied in the cutting for performing intermediate finishing or finishing.

  Furthermore, the technique disclosed in Patent Document 1 does not describe the inclination of the cutting tool during cutting, and increased the pick feed amount, the cutting feed speed, and the cutting amount as described above. There was a problem that no consideration was given to vibration generation and workpiece deformation accompanying the increase in cutting resistance.

  Further, Patent Document 2 defines that piercing is to send a cutting tool in the axial direction of the cutting tool, and when the cutting tool is tilted, the cutting tool suddenly idles from the cutting state. There was a problem that no consideration was given to lateral blurring caused by a sudden change in cutting resistance, such as entering the state of, or dropping of the cutting tool from the holder.

  Further, in Non-Patent Document 1, Non-Patent Document 2, Patent Document 1, and Patent Document 2, when cutting starts, the cutting tool suddenly enters the cutting state from the idle state, and the cutting resistance suddenly increases. There has been a problem that no consideration has been given to lateral blurring and damage to the cutting tool due to excessive increase.

  Therefore, the present invention realizes not only roughing but also cutting for performing intermediate finishing and finishing as well as roughing which can use a cutting tool other than a ball end mill. It is a first object that the present invention can be applied to a case where the shape of the above becomes a curved surface. In addition, the present invention suppresses the occurrence of vibration and workpiece deformation accompanying an increase in cutting resistance when increasing the pick feed amount, increasing the cutting feed speed, and increasing the cutting amount by realizing piercing. A second object is to realize highly efficient cutting.

  Furthermore, a third object of the present invention is to reduce abrupt changes in cutting resistance at the start and end of cutting in a state where the cutting tool is inclined, and interference between the workpiece and the cutting tool. To do.

The present invention for the purpose of the, based on the shape data and a plurality of types cutting tools selected from cutting tool information having a curved surface, the tool spindle direction vector with respect to traveling direction of the cutting tool, as far as possible backward There is provided a CAM device characterized by including an inclination angle setting means for setting an inclination angle so as to incline.

Further, the CAM apparatus, a cutting start operation setting means to set so as to penetrate the cutting tool at the start cutting the main axis of the cutting tool to the workpiece, further comprising being configured, and wherein A CAM device is provided.

  By configuring in this way, the CAM device according to the present invention can perform thrusting that can use a cutting tool other than a ball end mill, not only in roughing but also in cutting for intermediate finishing and finishing. Furthermore, the present invention can also be applied when the shape after cutting becomes a curved surface. In addition, according to the CAM device of the present invention, when the pick feed amount is increased, the cutting feed speed is increased, and the cutting amount is increased, vibration generation and workpiece deformation accompanying an increase in cutting resistance are suppressed, and high efficiency is achieved. Can be realized.

  Furthermore, by comprising in this way, it becomes possible to reduce the abrupt change of the cutting resistance at the start of cutting or at the end of cutting.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

First, the definition of each term used in the following embodiments will be described with reference to FIG.
FIG. 1 is a diagram illustrating a positional relationship between a workpiece and a cutting tool when a processing surface in a thrusting process is a convex shape, and FIG. 1A is a perspective view illustrating a positional relationship between the cutting tool and the workpiece. (B) is AA 'arrow sectional drawing in Fig.1 (a). In addition, since the basic structure about the name and code | symbols, such as the workpiece | work W, the cutting tool T, and an arrow, is common in FIG. 1, FIG. 4-9, it attaches | subjects and demonstrates the same code | symbol about a common element. Will be omitted.

As shown in FIG. 1, in the present embodiment, the workpiece W has a convex shape on the front side and a concave shape on the back side. The cutting tool T is a corner R end mill having a substantially cylindrical shape, provided with roundness around the bottom surface, and provided with blades (not shown) on the outer periphery and the bottom surface, respectively.
Here, the concave shape means that the machining surface in contact with the cutting tool T is recessed with respect to the cutting tool T, and the convex shape means that the machining surface in contact with the cutting tool T is in the cutting tool T. In contrast, it is rising.
An arrow 101 indicates the traveling direction of the cutting tool T. The cutting point is a contact point between the cutting tool T and the workpiece W at the time of cutting, and is a portion denoted by reference numeral 102 in FIG. In the present embodiment, the normal vector 103 indicates the normal vector at the cutting point 102 on the processing surface. The tool principal axis direction vector 104 is a vector indicating the principal axis direction of the cutting tool T, and includes a cutting point 102 in the present embodiment. The inclination angle θ is an angle formed by the normal vector 103 and the tool spindle direction vector 104, and the inclination angle is 0 ° when the normal vector 103 and the tool spindle direction vector 104 coincide. As is clear from the definition, it is possible to convert the inclination angle θ into the tool spindle direction vector 104. Furthermore, in this embodiment, all angles are positive in the direction opposite to the traveling direction 101 of the cutting tool T. For example, the inclination angle θ in FIG. 1B has a positive value. A line having a relationship of 90 ° or −90 ° with the normal vector 103 is called a tangent (not shown). In addition, when piercing is defined using these terms, piercing can be defined as machining in which the inclination angle of the cutting tool T during cutting is 0 ° or more.

FIG. 2 is a block diagram of a CAD / CAM system including a CAM device according to an embodiment of the present invention.
The CAD / CAM system 1 shown in FIG. 2 includes a CAD device 3 that creates product shape data, a file server 4 that stores data related to the dimensions of a cutting tool, and the shape data of a workpiece created by the CAD device 3 (hereinafter referred to as “CAD data”). CAM device 2 that sends the calculated tool trajectory data to the NC post processor 5 and the tool trajectory data sent from the CAM device 2 simultaneously. NC post processor 5 for converting to the coordinate system of the multi-axis control NC machine 7 and converting to NC data for numerical control, and operation commands for linear feed axes and rotary axes of the simultaneous multi-axis control NC machine 7 according to the NC data The numerical control device 6 for operating the simultaneous multi-axis control NC machine 7 and the linear feed axis and rotary axis operation commands created by the numerical control device 6 are prepared. Work Te, configured to include a simultaneous multi-axis control NC machine 7 for cutting the workpiece W.

(CAM device)
Further, the CAM device 2 creates a shape data reading unit 21 that reads shape data created by the CAD device 3, a cutting operation setting unit 22 that creates tool locus data based on the read shape data, and creates tool locus data. Based on the conditions input from the input unit 23 and the input unit 23 for inputting various conditions when performing the operation, the operation specifying unit 24 for selecting the operation of each unit included in the cutting operation setting unit 22 to be described later was created. The tool path data transfer unit 25 is configured to send tool path data to the NC post processor 5.

  The CAM device 2, the CAD device 3, and the file server 4 include a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), a hard disk drive, an input / output interface, and the like. Each unit of the CAM device 2, the CAD device 3, and the file server 4 is realized by developing a program stored in the hard disk drive of the computer in the RAM and executed by the CPU.

(Cutting operation setting part)
Further, the cutting operation setting unit 22 sets a machining range setting unit 221 that selects a part to be cut from the shape data according to the designation of the machining part via the input unit 23, and sets the cutting tool used for the cutting process. The tool setting unit 222 that acquires data on the dimensions of the tool from the file server 4 and sends the acquired data on the dimensions of the cutting tool to the interference check unit 2233 of the tool path data generation unit 223 to be described later, the tool path for generating the tool path The data generation unit 223 includes at least a cutting start operation setting unit 224 that sets a cutting start operation of the cutting tool, and a cutting end operation setting unit 225 that sets an end operation of the cutting tool.

(Tool path data creation part)
The tool trajectory data creation unit 223 acquires shape data from the initial value setting unit 2231 that sets the initial value of the tilt angle and the shape data reading unit 21, and creates a tool tip position vector based on the shape data. When interference occurs between the cutting tool and the workpiece at any point on the tool tip position vector created by the vector creation unit 2232 and the tool tip position vector creation unit 2232. The interference check unit 2233 for setting a flag, the interference determination unit 2234 for determining whether or not the flag has been set as a result of the interference check by the interference check unit 2233, the unevenness determination unit 2235 for determining the unevenness of the processed surface, and the inclination angle are changed. An inclination angle changing unit 2236 is configured to be included.

(Outline of CAD / CAM system processing)
Next, with reference to FIG. 2, an outline of processing of the CAD / CAM system 1 including the CAM device 2 according to the present invention will be described.
The shape data created by the CAD device 3 is sent to the shape data reading unit 21 of the CAM device 2 and further sent to the cutting operation setting unit 22. The cutting operation setting unit 22 creates tool path data based on the sent tool path data. Specifically, the cutting operation setting unit 22 creates tool trajectory data according to each procedure described below.

  The machining range setting unit 221 selects a part to be cut from the shape data according to the input designation of the machining part via the input unit 23. The tool setting unit 222 selects data related to the dimensions of the cutting tool used for the cutting process stored in the file server 4 by setting the cutting tool via the input unit 23. Further, the tool setting unit 222 acquires data related to the dimensions of the selected cutting tool from the file server 4, and the acquired data related to the dimensions of the cutting tool is a tool trajectory data creation unit 223, specifically an interference check described later. Send to part 2233. The tool path data creation unit 223 creates tool path data. The cutting start operation setting unit 224 sets the cutting start operation of the tool path, and the cutting end operation setting unit 225 sets the end operation of the tool path.

  Among these setting units, the processing range setting unit 221, the tool setting unit 222, and the cutting end operation setting unit 225 can be processed in any order. Therefore, the processing performed by these setting units is performed by selecting a setting unit to be processed by the operation designating unit 24 based on the information input via the input unit 23. Here, selection of a setting unit to be processed by the operation specifying unit 24 based on information input via the input unit 23 is, for example, setting a machining range on a display (not shown) connected to the CAM device 2 and a tool Items such as setting, tool path data creation, cutting start operation setting, cutting end operation setting are displayed, and an operator (not shown) selects the processing of the setting unit by selecting these with a cursor (not shown), etc. It is. However, the processing of the tool trajectory data creation unit 223 must be performed after at least the processing of the processing range setting unit 221 and the tool setting unit 222 is completed. Therefore, the processing of the tool trajectory data creation unit 223 enables the operation specifying unit 24 to select the processing of the tool trajectory data creation unit 223 after the processing of the machining range setting unit 221 and the tool setting unit 222 is completed. Here, after the processing of the machining range setting unit 221 and the tool setting unit 222 is finished, the operation specifying unit 24 can select the processing of the tool trajectory data creation unit 223, for example, on the display described above. However, after the processing of the machining range setting unit 221 and the tool setting unit 222 is completed, the item of tool trajectory data creation is displayed on the above-described display. It is displayed so that it can be selected. Further, the processing of the cutting start operation setting unit 224 must be performed after at least the processing of the tool trajectory data creation unit 223 is completed. Therefore, the processing of the cutting start operation setting unit 224 enables the operation specifying unit 24 to select the item of the cutting start operation setting on the above-described display after the processing of the tool locus data creation unit 223 is completed. To display.

  The tool trajectory data created by the cutting operation setting unit 22 is sent to the tool trajectory data transfer unit 25 and further sent to the NC post processor 5. The NC post processor 5 converts the tool path data into the coordinate system of the simultaneous multi-axis control NC machine 7 and converts it into NC data for the numerical controller 6. The numerical control device 6 creates an operation command for the linear feed axis and the rotary axis of the simultaneous multi-axis control NC machine 7 according to the NC data, and operates the simultaneous multi-axis control NC machine 7.

Next, the process of creating tool path data for piercing by the tool path data generating unit according to the embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a flowchart showing a flow of processing for creating tool path data for piercing. In addition, in this embodiment, although shown about the case where a corner R end mill is selected as the cutting tool T, you may select not only this but another rotary tool. The tool trajectory data in the present embodiment can be not only rough machining but also tool trajectory data used for cutting for performing, for example, intermediate finishing or finishing.

  First, the initial value of the inclination angle of the cutting tool T is set in the initial value setting unit 2231 (S31). At this time, the initial value of the tilt angle may be set via the input unit 23, and the initial value of the tilt angle corresponding to the unevenness of the processed surface and the curvature of the processed surface is stored in the file server 4 in advance as a table. In addition, the initial value setting unit 2231 may determine the unevenness of the processed surface and the curvature of the processed surface, and acquire the initial value of the inclination angle corresponding to the unevenness and the curvature from the file server 4. In the present embodiment, it is assumed that the initial value of the tilt angle is 90 °, that is, fixed to set the tool spindle direction vector 104 in the rearward tangential direction with respect to the traveling direction 101.

  Next, the initial value setting unit 2231 converts the initial value of the inclination angle into a tool spindle direction vector and sends the tool tip direction vector creation unit 2232. The tool tip position vector creation unit 2232 acquires shape data from the shape data reading unit 21. Further, the tool tip position vector creation unit 2232 acquires data on the dimensions of the selected cutting tool from the tool setting unit 222. The tool tip position vector creation unit 2232 creates a tool tip position vector based on the acquired shape data, the tool spindle direction vector, and data related to the dimensions of the selected cutting tool (S32), and creates the tool spindle direction vector and creates The tool tip position vector, shape data, and data related to the dimensions of the cutting tool are sent to the interference check unit 2233.

  Next, the interference check unit 2233 checks whether or not the cutting tool T and the workpiece W interfere with each other on the created tool tip position vector based on data on the shape data, the tool tip position vector, the tool dimensions, and the like. (S33). As a specific interference check method, for example, there is a method described in Norio Okino, methodology of automatic design, May 30, 1982, pp.146-148. When there is a location where interference occurs, the interference check unit 2233 sets a flag on the tool tip position vector at that location. Specifically, for example, a tool tip position vector and a flag are always stored as a pair of data, and 0 is stored as a pair of data in a tool tip position vector at a location where no interference occurs, and there is no interference. For example, 1 is stored as a pair of data in the tool tip position vector at the generated position. Next, the interference check unit 2233 sends the tool spindle direction vector, the tool tip position vector, the shape data, the data related to the dimensions of the cutting tool, and the flag to the interference determination unit 2234.

  The interference determination unit 2234 determines whether or not a flag is set in the result of step S33 (S34). If there is no interference part (S34 → no interference part), the process ends, that is, the creation of the tool path data ends, and the interference determination unit 2234 generates the generated tool path data, that is, the tool spindle direction vector and the tool tip position. The vector is sent to the tool path data transfer unit 25. When there is an interference part, that is, when 1 is present in the flag data (S34 → there is an interference part), the interference determination unit 2234 has a tool spindle direction vector, a tool tip position vector, shape data, a cutting tool dimension, etc. Is sent to the unevenness determination unit 2235, and the process proceeds to step S35.

  In step S <b> 35, the unevenness determination unit 2235 determines the unevenness of the processed surface based on the sent shape data and information input via the input unit 23. Here, based on the information input via the input unit 23, the unevenness of the processed surface is determined. For example, an operator (not shown) determines the unevenness of the processed surface, and the determination result is input via the input unit 23. The unevenness determination unit 2235 determines the unevenness based on the sent information. If the processed surface is concave (S35 → concave), the process proceeds to step S36. If the processed surface is convex (S35 → convex), the process proceeds to step S37. In any case, the unevenness determination unit 2235 sends data related to the tool spindle direction vector, tool tip position vector, shape data, cutting tool dimensions, and the like to the inclination angle change unit 2236.

In step S36, the inclination angle changing unit 2236 changes the inclination angle θ by reducing the inclination angle θ by a predetermined angle within a range of θ _a to θ _b described later. The calculation of the angle ranges (θ _a , θ _b ) in changing the tilt angle θ will be described in detail later. By setting it as such an angle range, it is possible to change the inclination angle θ while maintaining the state of piercing.

  In step S37, the tilt angle θ is changed by the tilt angle changing unit 2236 by reducing the tilt angle θ by a predetermined angle within a range of 0 ° to 90 °. The calculation of the angle range (0 °, 90 °) in changing the tilt angle θ will be described in detail later. By setting it as such an angle range, it is possible to change the inclination angle θ while maintaining the state of piercing.

  After changing the tilt angle θ in step S36 or step S37, the tilt angle changing unit 2236 converts the changed tilt angle θ into a tool spindle direction vector, and sends the tool spindle direction vector to the tool tip position vector creating unit 2232. The process returns to step S32.

  Next, a method for setting the tilt angle range in the tilt angle change process in steps S36 and S37 in FIG. 3 will be described with reference to FIGS. In the following figures, the roundness around the bottom surface of the corner R end mill is not shown in order to make the figures easy to see. The calculations in FIGS. 4 and 5 are all performed based on the shape data and data relating to the dimensions of the cutting tool.

(Inclination angle range when the machining surface is concave)
First, with reference to FIG. 4, the setting of the range of the tilt angle in the process of changing the tilt angle in step S36 of FIG. 3 when the processing surface is concave will be described.
FIG. 4 is a diagram illustrating a method of setting the range of the tilt angle in the process of changing the tilt angle in step S36 of FIG. 3 when the processed surface is concave. A workpiece W in FIG. 4 is a cross-sectional view taken along the line AA ′ in FIG.
When the processing surface is concave, as shown in FIG. 4A, the cutting tool T is inclined forward with respect to the traveling direction 101, and the bottom surface of the cutting tool T other than the cutting point 102 and the workpiece W are eventually formed. A contact point (first contact point 401) is obtained, and an inclination angle (first inclination angle θ _a ) at this time is obtained.
As shown in FIG. 4 (b), when the inclination angle theta of the cutting tool T is equal to or less than the first tilt angle theta _a, bottom and workpiece W of the cutting tool T interferes, narrowing cutting occurs.
Next, as shown in FIG. 4C, the cutting tool T is inclined backward with respect to the traveling direction 101, and eventually the side of the cutting tool T other than the cutting point 102 comes into contact with the workpiece W (first). 2 contact point 402), and the inclination angle (second inclination angle θ _b ) at this time is obtained.
As shown in FIG. 4D, when the inclination angle θ of the cutting tool T becomes equal to or larger than the second inclination angle θ _b , the side surface of the cutting tool T and the workpiece W interfere with each other to cause cutting.
Therefore, the machined surface is the case of concave, as shown in FIG. 4 (e), the inclination angle theta is the first tilt angle theta _a higher, must be less than or equal to the second inclination angle theta _b.
The calculation of the range of the inclination angle θ may be performed at an arbitrary point on the tool path or may be performed at a cutting start point.
By setting it as such an angle range, it is possible to change the inclination angle θ while maintaining the state of piercing.

(Inclination angle range when the machining surface is convex)
Next, with reference to FIG. 5, the setting of the range of the tilt angle in the process of changing the tilt angle in step S37 of FIG. 3 when the processed surface is convex will be described.
FIG. 5 is a diagram showing a method of setting the range of the tilt angle in the process of changing the tilt angle in step S37 in FIG. A cross-sectional view is shown.
When the processing surface is convex, as shown in FIG. 5A, the cutting tool T is inclined forward with respect to the traveling direction, and the work W comes into contact with the bottom surface of the cutting tool T other than the cutting point. A point is obtained, and the inclination angle (third inclination angle θ _c ) at this time is obtained. At this time, the bottom surface of the cutting tool T coincides with the tangential plane at the cutting point 102. Therefore, the third inclination angle θ _c in this embodiment is 0 °.
As shown in FIG. 5B, when the inclination angle θ of the cutting tool T is 0 ° or less, the bottom surface of the cutting tool T and the workpiece W interfere with each other, and cutting occurs.
Next, as shown in FIG. 5 (c), the cutting tool T is inclined backward with respect to the traveling direction, and the point where the side surface of the cutting tool T other than the cutting point comes into contact with the workpiece W is obtained. To obtain the tilt angle (fourth tilt angle θ _d ). The tool spindle direction vector 104 at this time coincides with a tangent at the cutting point 102. Therefore, the fourth inclination angle θ _d in this embodiment is 90 °.
As shown in FIG. 5D, when the inclination angle θ of the cutting tool T is 90 ° or more, the side surface of the cutting tool T and the workpiece W interfere with each other, and cutting occurs.
Therefore, in the cutting process using the corner R end mill, when the processing surface is convex, the inclination angle θ must be 0 ° or more and 90 ° or less as shown in FIG.
The calculation of the range of the inclination angle θ may be performed at an arbitrary point on the tool path or may be performed at a cutting start point.
By setting it as such an angle range, it is possible to change the inclination angle θ while maintaining the state of piercing.

Next, the operation of the cutting tool set in the cutting start operation setting unit according to the embodiment of the present invention will be described with reference to FIGS. 2 and 3 and FIG.
FIG. 6 is a diagram illustrating the operation of the cutting tool set in the cutting start operation setting unit according to the embodiment of the present invention.
When the simultaneous multi-axis control NC machine 7 enters actual cutting based on the tool path data created by the tool path data creating unit 223, the cutting tool T suddenly moves from the idle state to the workpiece W. In order to enter the cutting, the cutting load increases rapidly unless the operation before the first cutting is considered. As a result, problems such as deformation of the workpiece W and breakage of the cutting tool T may occur.
In the present embodiment, the cutting start operation setting unit 224 sets the cutting start position at a position (Ta) where the cutting tool T is moved in the tool spindle direction so that the cutting tool T can enter from the tool spindle direction at the first cutting position. To do. The tool spindle direction vector 104 at this time is converted from the inclination angle θ set by the tool trajectory data creation unit 223 in step S36 and step S37 in FIG. By setting in this way, since the cutting tool T enters the workpiece W from an oblique direction, the cutting resistance against the cutting tool T when entering the cutting process can be reduced. As a result, it is possible to prevent lateral blurring at the start of cutting of the cutting tool T and damage to the cutting tool T.

Next, the operation of the cutting tool set in the cutting end operation setting unit according to the embodiment of the present invention will be described with reference to FIGS. 2 and 3 and FIG.
FIG. 7 is a diagram illustrating an operation of the cutting tool set in the cutting end operation setting unit according to the embodiment of the present invention.
When the simultaneous multi-axis control NC machine 7 finishes the actual cutting process based on the tool path data created by the tool path data creation unit 223, the cutting state suddenly changes from the cutting state to the idling state. A sudden change occurs, or sometimes the workpiece W and the side surface of the cutting tool T interfere with each other. As a result, there is a concern that the cutting tool T may drop off from a holder (not shown) that fixes the cutting tool T.
In the present embodiment, as shown in FIG. 7, the cutting end operation setting unit 225 extends from the last cutting point 102 a to, for example, an arc 701 having a center C in the normal direction along the traveling direction of the cutting tool T. It is set to move (T → Tb) and move the cutting tool T to finish. By setting in this way, the workpiece W and the cutting tool T can be set so as to be gradually separated from each other, so that the interference between the workpiece W and the cutting tool T at the end of cutting and a sudden change in the cutting load can be reduced. it can.

With reference to FIG. 9 describing the above-described conventional technique, the operation when the butt process is applied to the cutting process will be described with reference to FIG.
FIG. 8 is a diagram illustrating a state in which the tool spindle direction vector is set to be tilted rearward with respect to the traveling direction of the cutting tool.
As shown in FIG. 9, when the cutting tool T is tilted forward with respect to the traveling direction 101, the cutting force 105 is in the same direction as the traveling direction 101 of the cutting tool T and perpendicular to the normal vector 103 of the workpiece W. Occurs. This cutting force 105 can be decomposed into a component perpendicular to the tool spindle direction 104 ′ (tool spindle vertical direction component) 106 and a tool spindle direction component 107. Since the tool spindle vertical direction component 106 is larger than the tool spindle direction component 107, a large force is applied to the tool spindle vertical direction component 106 of the cutting tool T. In the cutting tool T, the tool spindle vertical direction component 106 is less rigid than the tool spindle direction 104 ′. Therefore, if a large force is generated in the tool spindle vertical direction component 106, the cutting tool T is likely to vibrate.
On the other hand, in the piercing according to the method of determining the tool spindle direction vector according to the present invention as shown in FIG. 8, the tool spindle vertical direction component 106 is smaller than the tool spindle direction component 107, and therefore the tool spindle of the cutting tool T A large force is applied in the direction 104 ′. Since the cutting tool T has higher rigidity in the tool spindle direction 104 ′ than the tool spindle vertical direction component 106, the cutting tool T is less likely to vibrate even if a large force is generated in the tool spindle direction 104 ′. Further, since a large force acts in the tool spindle direction 104 ′ having a high rigidity, it is possible to withstand a higher cutting load.
From the above results, in cutting processing using thrusting, vibration generation and workpiece deformation caused by an increase in cutting resistance accompanying an increase in processing speed can be suppressed, enabling highly efficient cutting. Become.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented.
For example, in the present embodiment, it is assumed that a corner R end mill is selected as the cutting tool T, but other rotary cutting tools can also be selected. In this case, the first to fourth inclination angles θ _a , θ _b , θ _c , and θ _d in FIGS. 4 to 5 are based on the data regarding the dimensions of the respective rotary cutting tools and the shape data. By using the calculated angle, the same processing can be performed.

  Further, in the present embodiment, the movement of the cutting tool T at the end of the cutting operation in the cutting end operation setting unit 225 is arcuate and downward, but is not limited thereto, and is not limited to this. Also good. Moreover, it is not limited to the arc shape, but may be another curved shape.

  Further, in the present embodiment, the tool setting unit 222 in FIG. 2 selects data related to the size of the cutting tool T used for cutting stored in the file server 4 by setting the cutting tool T via the input unit 23. However, the present invention is not limited to this. For example, the tool setting unit 222 selects the cutting tool T via the input unit 23 and interferes with the name of the selected cutting tool. The data may be sent to the check unit 2233, and the interference check unit 2233 may acquire data related to the size of the cutting tool selected from the file server 4 based on the name of the sent cutting tool.

  Furthermore, in this embodiment, the unevenness determination unit 2235 in FIG. 2 determines the unevenness of the processed surface based on the information acquired via the input unit 23 in FIG. 2. 2235 may automatically determine the unevenness of the processed surface by analyzing the differential coefficient of the processed surface.

  Further, the file server 4 of FIG. 2 may be a database. At this time, the database may be separated from the CAD device 3 or the CAM device 2, integrated with the CAD device 3, or integrated with the CAM device 2.

It is a figure which shows the positional relationship of the workpiece | work and cutting tool in case the process surface in thrusting is convex shape, (a) Perspective view which shows the positional relationship of a cutting tool and a workpiece | work, (b) AA in (a). FIG. 1 is a block diagram of a CAD / CAM system including a CAM device according to the present invention. It is a flow which shows the flow of a process of preparation of the tool locus data for piercing. It is a figure which shows the setting method of the range of the inclination angle in the process of the inclination angle change of step S36 of FIG. 3 when a processed surface is concave shape. It is a figure which shows the setting method of the range of the inclination angle in the process of the inclination angle change of step S37 of FIG. 3 when a process surface is convex shape. It is a figure which shows operation | movement of the cutting tool set in the cutting start operation | movement setting part which concerns on embodiment of this invention. It is a figure which shows operation | movement of the cutting tool set in the cutting completion operation | movement setting part which concerns on embodiment of this invention. It is the figure which showed the state which inclined and set the tool principal axis direction vector back with respect to the advancing direction of a cutting tool. It is the figure which showed the state which inclined and set the tool spindle direction vector with respect to the advancing direction of the cutting tool.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 CAM apparatus 3 CAD apparatus 4 File server 21 Shape data reading part 22 Cutting operation setting part 23 Input part 24 Operation designation part 25 Tool locus data transfer part 101 Advancing direction 102,102a Cutting point 103 Normal vector 104,104 ' Tool spindle Direction vector 221 Machining range setting unit 222 Tool setting unit 223 Tool path data generation unit 224 Cutting start operation setting unit 225 Cutting end operation setting unit 2231 Initial value setting unit 2232 Tool tip position vector generation unit 2233 Interference check unit 2234 Interference determination unit 2235 Concavity and convexity determination unit 2236 Inclination angle changing unit θ, θ ′ Inclination angle T, Ta, Tb Cutting tool W, W ′ Workpiece

Claims (5)

A shape data reading means for reading shape data of a processing object having a curved surface, created by a CAD device;
Storage means for storing information on the shapes of various cutting tools;
A tool setting unit that selects a type of the cutting tool and acquires information on the shape of the selected cutting tool from the storage unit;
Tool path data creating means for creating tool path data;
A CAM device for performing intermediate finishing and surface finishing of a workpiece,
The tool trajectory data creation means includes
Obtaining the shape data from the shape data reading means, obtaining information on the shape of the selected cutting tool from the tool setting means,
The initial value of the angle of the cutting tool is set so that a tool spindle direction vector indicating the spindle direction of the cutting tool is aligned with the tangential direction behind the cutting tool in the traveling direction,
In a state where the angle of the cutting tool is an initial value, based on the shape data and information on the shape of the cutting tool, create tool trajectory data including the tool spindle direction vector,
Based on the tool trajectory data, the shape data, and information on the shape of the cutting tool, an interference check is performed to determine whether or not the cutting tool and the object to be processed interfere with each other.
As a result of the interference check, when it is determined that the cutting tool and the workpiece do not interfere with each other, the tool trajectory data is output,
As a result of the interference check, when it is determined that there is a portion where the cutting tool and the processing object interfere with each other , by calculating and analyzing a differential coefficient of the cutting surface based on the shape data, , Determine the unevenness of the cutting surface,
As a result of the determination, when the cutting surface is a concave surface, the cutting tool is inclined backward with respect to the course direction using the acquired shape data and information on the shape of the selected cutting tool. An angle of the cutting tool with respect to the cutting surface when the cutting tool is virtually tilted back and forth around the cutting point in the state and the bottom and side surfaces of the cutting tool are in contact with the workpiece. Calculating a tilt angle of 1 and a second tilt angle;
Determining a third tilt angle within the range of the first tilt angle and the second tilt angle;
As a result of the determination, when the cutting surface is a convex surface, the angle of the cutting tool with respect to the cutting surface is 0 using the acquired shape data and information on the shape of the selected cutting tool. The third inclination angle is determined so that the tool spindle direction vector approaches 90 ° rearward within a range of 90 ° rearward relative to the course direction from
Based on the third inclined angle of the determined, to create a tool path data including the pre-SL tool spindle direction vector,
When the cutting force in the tool advancing direction is broken down into a force in the tool spindle direction and a force in the direction perpendicular to the tool spindle, the force in the direction perpendicular to the tool spindle is smaller than the force in the tool spindle direction. The CAM device is characterized in that the third angle is determined. The CAM device
It further includes a cutting start operation setting means for executing a procedure for setting the cutting tool so as to enter the workpiece from the main axis direction of the cutting tool in a state where the cutting tool is inclined rearward with respect to the cutting surface. To do,
The CAM device according to claim 1. A shape data reading means for reading shape data of a processing object having a curved surface, created by a CAD device;
Storage means for storing information on the shapes of various cutting tools;
A tool setting unit that selects a type of the cutting tool and acquires information on the shape of the selected cutting tool from the storage unit;
Tool path data creating means for creating tool path data;
A tool trajectory creation method in a CAM device for performing intermediate finishing and surface finishing of a workpiece,
The tool trajectory data creating means is
A procedure for obtaining the shape data from the shape data reading means and obtaining information on the shape of the selected cutting tool from the tool setting means,
The shape data and the cutting tool in the state where the angle of the cutting tool is an initial value set so as to match the tool spindle direction vector indicating the spindle direction of the cutting tool with the tangential direction behind the cutting tool in the traveling direction A procedure for creating tool path data including the tool spindle direction vector based on information on the shape of
A procedure for performing an interference check as to whether or not the cutting tool and the object to be processed interfere based on the tool trajectory data, the shape data, and information on the shape of the cutting tool,
As a result of the interference check, when it is determined that the cutting tool and the workpiece do not interfere with each other, a procedure for outputting the tool trajectory data;
As a result of the interference check, when it is determined that there is a portion where the cutting tool and the processing object interfere with each other , by calculating and analyzing a differential coefficient of the cutting surface based on the shape data, , A procedure for determining unevenness of the cut surface,
As a result of the determination, when the cutting surface is a concave surface, the cutting tool is inclined backward with respect to the course direction using the acquired shape data and information on the shape of the selected cutting tool. An angle of the cutting tool with respect to the cutting surface when the cutting tool is virtually tilted back and forth around the cutting point in the state and the bottom and side surfaces of the cutting tool are in contact with the workpiece. A procedure for calculating a tilt angle of 1 and a second tilt angle;
Determining a third tilt angle within a range of the first tilt angle and the second tilt angle;
As a result of the determination, when the cutting surface is a convex surface, the angle of the cutting tool with respect to the cutting surface is 0 using the acquired shape data and information on the shape of the selected cutting tool. When the cutting force in the tool advancing direction is decomposed into a force in the tool spindle direction and a force in the direction perpendicular to the tool spindle within a range of 90 ° rearward with respect to the path direction, the tool spindle direction A step of determining the third inclination angle so that a force perpendicular to the tool spindle is smaller than the force of the tool and the spindle direction of the tool approaches 90 ° rearward ;
Procedure on the basis of the third inclined angle of the determined, to create a tool path data including the pre-SL tool spindle direction vector,
A tool path creation method, characterized in that the run Nde free. The CAM device is
A procedure for setting the cutting tool so as to enter the workpiece from the main axis direction of the cutting tool in a state where the cutting tool is inclined backward with respect to the cutting surface.
The tool path creation method according to claim 3, further comprising:   A tool trajectory creation program for causing a computer to execute the tool trajectory creation method according to claim 3 or 4.

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