Processor system, machining path generation method and program

Abstract

To reduce deterioration of machining accuracy, caused by an error before cutting of a material, or early wear of a cutting tool.SOLUTION: A method and a system include: (1) acquiring a three-dimensional shape of a material; (2) calculating roughness information of the material from the three-dimensional shape of the material; (3) generating a material contour from the three-dimensional shape of the material; (4) based on the roughness information, moving the material contour to the inner side of the material; and (5) based on the moved material contour, generating a machining path for cutting a surface of the material.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to processing of materials, particularly to cutting processing technology. Note that the material is an object to be processed, and it may be called a workpiece, a work material, a raw material, or the like. [Background technology]

[0002] In recent years, cutting processes are performed on materials by inputting NC programs (sometimes referred to as NC data in this specification) into NC-compatible lathes. In the manufacturing processes of various products, one example is the removal of the surface of materials produced by plastic processing, casting, etc., by cutting. As mentioned above, before cutting, materials are typically shaped by processes other than removal processes (casting, forging, build-up, etc.).

[0003] However, since processing other than removal processing has lower processing accuracy than removal processing, the actual shape and dimensions of the material may differ from the expected shape and dimensions. Patent Document 1 discloses a technology aimed at early detection of cases where the desired shape after cutting cannot be obtained due to shape errors in the workpiece before cutting. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-108428 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology of Patent Document 1 cannot eliminate the deterioration of machining accuracy or premature wear of cutting tools caused by errors before cutting the material. The present invention aims to reduce the deterioration of machining accuracy or premature wear of cutting tools caused by errors before cutting the material. [Means for solving the problem]

[0006] The present invention provides a processor system that solves the above-described problems, the processor system having one or more processors and one or more storage resources that store a machining path generation program, By executing the machining path generation program, the processor: (1) Obtain the three-dimensional shape of the material, (2) From the three-dimensional shape of the material, The difference between the convexity of the outer surface, which is the most protruding position on the outer surface of the material, and the concavity of the outer surface, which is the most recessed position on the outer surface, and the difference between the convexity of the inner surface, which is the position closest to the rotation axis on the inner surface of the material, and the concavity of the inner surface, which is the most recessed position on the inner surface, are shown. Calculating unevenness information of the material; (3) From the three-dimensional shape of the material, Shows the outline of the material Generate material contours, (4) moving the material contour line to the inside of the material based on the unevenness information; (5) A system for generating a machining path for cutting the surface of a material based on the material contour line after movement. The present invention also includes a machining path generation method using the system and a program for executing the method. [Effects of the Invention]

[0007] The present invention can reduce deterioration of machining accuracy or early wear of cutting tools caused by errors before cutting a material. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an overall configuration diagram of a processing system. [Figure 2] FIG. 10 is a diagram illustrating the configuration of another three-dimensional shape measuring device in the processing system. [Figure 3] 10 is a flowchart showing an NC data generation process. [Figure 4] 10A to 10C are diagrams illustrating characteristics of NC data generated by the NC data generation process. [Figure 5] FIG. 10 is another diagram showing the characteristics of the NC data generated in the NC data generation process. [Figure 6] 10A to 10C are other diagrams showing the characteristics of the NC data generated in the NC data generation process. [Figure 7]FIG. 10 is yet another diagram showing the characteristics of the NC data generated in the NC data generation process. [Figure 8] FIG. 2 is a block diagram showing a configuration of a processing path generating device. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below with reference to the drawings. For ease of explanation, the following case will be described in this embodiment. Other examples will be described later in the variations. *An example of removal processing is when a cutting tool is used to cut a rotating material (i.e., cutting). *The machining path during cutting is specified by NC data. Furthermore, the path expressed by the machining path is the path of the cutting tool (more specifically, the path of the cutting edge of the tool). *Cutting is divided into rough machining and finish machining. Of these, finish machining involves changing the machining conditions from rough machining to reduce machining errors and smooth the machined surface compared to rough machining. Examples of machining conditions that can be changed include the tool used, chuck rotation speed (same as spindle rotation speed), moving speed of the cutting tool 3, depth of cut, and contact angle of the tool with the material 1. *There is an oxide layer (black skin) on the surface of material 1.

[0010] <Processing system configuration> Fig. 1 is an overall configuration diagram of a machining system 10 in this embodiment. The machining system 10 in Fig. 1 includes a machine tool 2 on which a material 1 is placed and which cuts the material, a cutting tool 3, a measuring device 4, a control device 6 which controls the cutting tool 3 and the measuring device 4 (which may be partly or entirely included in the machine tool 2, or may be a device external to the machine tool 2), and a machining path generating device 7. Each of these will be described below.

[0011] <<Machine tools 2>> The machine tool 2 in this embodiment is a device that performs cutting on a material 1. Examples of the machine tool 2 are lathes (vertical lathe, bench lathe, face lathe, and turret lathe are examples) and machining centers (material 1 is attached to a spindle to which tools are attached). In the following explanation, a vertical lathe will be used as an example. Note that in Figures 1 and 2, only the chuck (a component that fixes and rotates material 1), which is a component of the machine tool 2, is shown, and components that are typically included in a lathe, such as the spindle and tool rest, are omitted. Note that in the following explanation, the term "rotation axis of the chuck" is used, but this rotation axis is also the rotation axis of the spindle.

[0012] FIG. 1(a) is a front view of the vertical lathe, and FIG. 1(b) is a diagram showing the chuck and the workpiece 1 fixed to the chuck as seen from above.

[0013] <<Material 1 (before cutting)>> The material 1 assumed in this example will be described with reference to Fig. 1(b). The material 1 before cutting in this example has the following characteristics. *Materials manufactured by processes other than subtractive processing, such as plastic processing and casting, that are generally axially symmetrical (they have irregularities and are not completely axially symmetrical). *An oxide layer (black scale) exists on the surface. Note that the black scale is omitted in Figure 1(a), but is represented by the thick outline of Material 1 in Figure 1(b).

[0014] In Figure 1(a), the rotation axis of the chuck is shown by a dashed line drawn in the vertical direction through the center of the material. In Figure 1(b), the rotation axis of the chuck is shown by a dashed line with the interior drawn in gray. For simplicity of explanation, in the example in Figure 1, the outer shape of material 1 is shown as a circular tube with the following characteristics: *When viewed from the perspective of Figure 1(b), the thickness of the upper side is thicker (i.e., there is a convexity) and the thickness of the lower side is thinner (i.e., there is a concavity). *There is black skin on the outside of the tube.

[0015] <<Cutting tool 3>> The cutting tool 3 is a tool that is fixed to a tool rest (not shown) of the machine tool 2 and performs cutting by coming into contact with the rotating workpiece 1. In the following explanation, it may be said that the cutting tool 3 moves, but more accurately, it means that the cutting tool 3 moves when the tool rest moves. The movement of the cutting tool 3 only needs to be relative to the workpiece 1, and in reality, the cutting tool 3 may be moved or the workpiece 1 may be translated.

[0016] <<<Cutting tool 3 coordinate system>>> The machine tool 2 that performs cutting can move the cutting tool 3 in at least two axial directions. In other words, the machining path of the cutting tool (or the cutting edge of the cutting tool 3, or the tool rest) can be described in a Euclidean coordinate system with at least two axes. In the vertical lathe shown in Figure 1(a), the z-axis parallel to the rotation axis of the chuck and the x-axis perpendicular to the rotation axis of the chuck are shown as two axes. In the following, for the sake of simplicity, the x-axis and z-axis will be further defined as follows: *The x-axis and z-axis indicate the position of the cutting edge of the cutting tool 3. *The origin is on the upper surface of the chuck and on the rotation axis, and the z-axis is positive in the direction away from the upper surface of the chuck, and the x-axis is positive in the direction away from the chuck rotation axis.

[0017] In addition, in FIG. 1(a), the y-axis is also shown in preparation for explanation in the Euclidean coordinate system, but this axis is not essential when describing the machining path in NC data.

[0018] <<Cylindrical coordinate system>> The x-axis and z-axis are coordinate systems assigned to the non-rotating cutting tool, tool post, or cutting edge, so using them for the rotating material 1 would complicate the explanation. Therefore, in the following explanation, a cylindrical coordinate system will be used for the material 1. In the cylindrical coordinate system, the three coordinate components (ρ, φ, cz) of a given point P are given as follows: *Radial distance ρ = Euclidean distance from the reference axis to point P *Azimuth angle φ = the angle between the reference direction on the reference plane and the line connecting the origin and the orthogonal projection of point P onto the reference plane. *Height cz = distance from the reference plane to point P Here, the reference axis is the rotation axis of the chuck, the reference direction is the x-axis direction in Figure 1(a), and the reference plane perpendicular to the reference axis is the upper surface of the chuck. In other words, the intersection of the upper surface of the chuck and the rotation axis is the origin O (ρ = 0, φ = 0 degrees, cz = 0). Note that the reference direction is not a direction fixed to the chuck, but is parallel to the cutting tool 3 or the first movement axis of the tool post. In other words, even if the chuck rotates due to the spindle, the reference direction does not rotate in accordance with the rotation of the chuck.

[0019] The coordinates in the cylindrical coordinate system that will be most commonly used in the following explanation are the radial distance ρ and the height cz.

[0020] <<Measuring equipment>> The measuring device (hereinafter sometimes referred to as the shape measuring device) is a device that measures the shape of the material 1 (particularly the shape before cutting). The measuring device may be a non-contact measuring device that uses, for example, the light section method, the fringe interference method, or the FMCW method, but it may also be a contact type measuring device that uses a touch probe or the like. In this embodiment, the measuring device outputs the shape of the material 1 measured using such a measurement method as three-dimensional point cloud data. In generating the three-dimensional point cloud data, the measuring device may also acquire the rotation angle of the chuck.

[0021] FIG. 2 shows another example of measurement using measuring instruments. The difference from FIG. 1 is that there are multiple measuring instruments (measuring instruments 4 and 5) and the measuring instruments are fixed to a tool post, and the tool post is moved to measure a wider range. Note that the mechanism for moving the measuring instruments may be other than a tool post, for example, an arm. Furthermore, the measuring instruments may be the devices disclosed in JP 2020-051892 filed by the applicant of the present application.

[0022] <<Control device 6>> The control device 6 is a device that receives NC data from the user of the machine tool 2 or from another device, and controls the rotational speed of the spindle and the movement of the cutting tool in accordance with the NC data. An example of the control device 6 is a computerized numerical control device. The control device 6 typically includes a processor, a storage resource 72, and a user interface. The control device 6 may also have a peripheral interface such as a network interface device or USB. Specific examples of each component may be the same as those of the machining path generation device 7, which will be described later. In other words, the control device 6 may be a processor system. The control device 6 and the machining path generation device 7 may also be common hardware.

[0023] <Processing path generation device 7> FIG. 8 illustrates a processing path generation device 7. The processing path generation device 7 includes at least one or more processors 71 and one or more storage resources 72. Examples of processors include a central processing unit (CPU), a graphics processing unit (GPU), and a field-programmable gate array (FPGA). However, other circuits may be used as long as the computer can execute the processes described below. The storage resource 72 may be a non-volatile memory such as a hard disk drive (HDD) or a solid state drive (SSD), a volatile memory such as an SRAM or a DRAM, or a combination of volatile and non-volatile memory. Although not shown, the processing path generation device 7 may also include a user interface device, a network interface device, and a peripheral interface device. Examples of processing path generation devices 7 include personal computers, server computers, cloud servers, tablet computers, smartphones, and combinations thereof. Because each device includes one or more processors and one or more storage resources, these devices or groups of devices are collectively referred to as a processor system.

[0024] The memory resource 72 stores at least a machining path generation program 721. By the processor 71 reading and executing the machining path generation program from the memory resource 72, the machining path generation process, which will be described later, is performed. Therefore, the execution entity of the machining path generation process can be said to be either the processor 71, the machining path generation device 7, or the machining path generation program 721. Note that the machining path generation program 721 may be stored in a non-volatile storage medium (not shown) or another processor system. From these, it can be said that the machining path generation program 721 may be installed in the machining path generation device 7.

[0025] <<Data>> Hereinafter, some of the data generated (including temporary generation) and referred to in the NC data generation process will be described. These data may be stored (including temporary storage) in the memory resource 72 or in the cache memory of the processor 71.

[0026] <<<NC Data (Generated NC Data, Referenced NC Data) 740>>> The NC data (NC program) 740 is data that includes at least the path of the cutting tool and the rotation speed of the chuck (accurately, the rotation speed of the spindle). Note that the NC data 740 may include other items that can be represented by other NC programs. Note that the NC data 740 in this embodiment includes, in addition to the NC data (generated NC data) generated by the NC program generation program, NC data (referenced NC data) that is referenced as an option.

[0027] <<<Material Three-Dimensional Shape Data 731>>> The material three-dimensional shape data 731 is data indicating the three-dimensional shape of the material 1. Typically, it is generated by measuring with the shape measuring devices 4 and 5 in FIGS. 1 and 2 and performing preprocessing as necessary. Typically, the material three-dimensional shape data 731 is a group of point data (point cloud data) represented according to the Euclidean coordinate system or the cylindrical coordinate system.

[0028] <<<Shape Contour Line Data 735>>>> In the case of turning, it is difficult to precisely match the rotation angle of the material 1 with the position of the cutting tool 3. This is because the material 1 is rotated not by a stage but by a spindle that rotates at high speed. Therefore, it is difficult to change the position of the cutting tool 3 when the rotation angle of the material 1 reaches a predetermined angle. To accommodate such situations, the shape contour data 735 (and material contour data 736, described later) is shape data that represents the three-dimensional shape of the material 1 by reducing it to two dimensions: a radial distance ρ (sometimes referred to as a representative radial distance) in a cylindrical coordinate system and a height cz. The representative radial distance (cz1) for a predetermined height cz1 is calculated as follows: *Representative radial distance of the outer surface of the material (cz1) = The largest radial distance ρ of the outer surface of height cz1 distance. *Representative radial distance (cz1) on the inner surface of the material = The smallest radial distance ρ on the outer surface of height cz1.

[0029] An example of the representative radial distance is shown in Figure 4. Figure 4 corresponds to an enlarged upper right portion of the material 1 in Figure 1(b). Note that compared to Figure 1, the unevenness on the outside is more emphasized, and the eccentricity of the inner surface is depicted somewhat more gently. For the material shape of the outer surface of material 1 such as surface 201, the radial distance ρout_max of the most protruding position pout_max on the outer surface (sometimes referred to as the convexity of the outer surface) is the representative radial distance. For the inner surface of the material shape of material 1 such as surface 210, the radial distance ρin of the position pin closest to the rotation axis cz on the inner surface (sometimes referred to as the convexity of the inner surface) is the representative radial distance. Note that in this specification, a convex portion may be referred to as a mountain, and a concave portion may be referred to as a valley.

[0030] <<<Material outline data 736>>> When a portion of the material 1 other than the chuck fixing portion is to be cut, the material contour data 736 is the material contour itself stored in the shape contour data 735. On the other hand, when cutting a portion of the material 1, the shape contour included in the region to be cut is stored in the material contour data 736. Note that, because this is a device for reducing the calculation load for the region not to be cut, the shape contour may also be used as the material contour in this case. In other words, the material contour can also be said to be shape data that represents all or a portion of the material 1 by reducing its dimensions to two dimensions: the radial distance ρ (which can also be said to be the representative radial distance) and the height cz in a cylindrical coordinate system.

[0031] <<<Material unevenness data 737>>> The material unevenness amount data 737 is data indicating the amount of unevenness for each height cz. It can also be said that the material unevenness amount data 737 is data indicating the amount of unevenness lost in the dimensionality reduction of the shape contour or material contour. The convexity of the outer surface and inner surface is as explained above. The concavity of the outer surface refers to the most recessed position on the outer surface, such as position pout_min. The concavity of the inner surface refers to the most recessed position on the inner surface. Based on this, the amount of unevenness is as follows: *Amount of unevenness on the outer surface = ρout_max - ρout_min *Concave / convex amount for inner surface = ρin - concave amount of inner surface ρ The amount of unevenness for each height cz does not have to be the two mentioned above. If there is no inner surface, one amount will suffice, and if the shape of the material 1 has a more complex nested structure, such as a first outer surface - first inner surface - second outer surface - second inner surface from the outside, the amount of unevenness will be four. Also, the amount of unevenness for the upper surface of the material 1 may be independent of the other amounts of unevenness, as shown in Figure 6, which will be explained later. The amount of unevenness of the material may be considered to be a dimensional compression of the azimuth angle φ and the radial distance ρ for each height cz indicated by the three-dimensional shape of the material into a value for each height cz.

[0032] <<<Cutting target contour line data 732>>> The cutting target contour line data 732 is data indicating the target contour line of the material after cutting. When the cutting of the material 1 is divided into roughing (phase) and finishing (phase) and cut in phases, the cutting target contour line is the target contour line after finishing. Note that the cutting target contour line data 732 may be expressed as a combination of the height cz and the radial distance ρ, similar to the shape contour line and the material contour line. In other words, the contour line may be defined in the two-dimensional space (plane) of the height cz and the radial distance ρ.

[0033] Note that the cutting target contour line may be obtained by, for example, any of the following methods. * The machining path generation device 7 reads data (e.g., CAD data) indicating the three-dimensional shape of the material after cutting, generates the cutting target contour line, and stores it in the data 732. * By virtually executing the reference NC data with a simulator program that simulates the operation of the machine tool 2, the three-dimensional shape of the material after cutting is calculated.

[0034] <<<Target finishing allowance thickness data 733 (optional)>>> The target finishing allowance thickness is an option when the cutting conditions of the material 1 are divided into roughing and finishing in the cutting process, and it is the target value of the minimum thickness (or average thickness) of the material to be cut in the finishing phase. The target finishing allowance thickness data 733 stores such a target finishing allowance thickness.

[0035] <<<Assumed scale thickness data 734 (optional)>>> The assumed scale thickness indicates an assumed value of the scale thickness existing on the surface of the material 1. Typically, the assumed scale thickness is a value obtained by adding a margin amount to the maximum scale thickness assumed for the material 1, but the average scale thickness assumed for the material 1 may also be used. The assumed scale thickness data 734 stores such an assumed scale thickness.

[0036] <<<NC data details>>> Note that the machining path in this embodiment is the machining path indicated by the G code (or an aggregate of one or more G codes and other codes that affect the G code) in the NC program.

[0037] <Features of the NC data generated by the NC data generation process or features of the NC data generation process> The features of the NC data generated by the NC data generation process will be described using FIGS. 4 to 7. The features of the generated NC data generated in this embodiment are as follows.

[0038] (Feature 1) In order to reduce discontinuous cutting, which causes deterioration in accuracy or premature wear of the cutting tool 3, the frequency with which the cutting tool 3 separates from the workpiece 1 is reduced (ideally, the cutting tool 3 is always in contact with the workpiece 1 during cutting at height cz). For this purpose, as shown in FIG. 5, the machining path 203 of the generated NC data is a machining path such that the cutting edge is positioned at a position moved inside the workpiece 1 by the amount of roughness from the representative radial distance indicated by the shape contour line or the workpiece contour line.

[0039] (Feature 2) On the other hand, in order to make the quality after finish machining constant, a rough machining-oriented machining path that leaves a finishing allowance is generated. In FIG. 5, the rough machining path 203 maintains the distance from the cutting target contour line 204 by the target finish thickness. Note that the example in FIG. 5 is an example limited to the case where the maximum allowable cutting amount of the cutting tool is sufficiently large and cutting can be performed from the surface 201 to the cutting target contour line 204.

[0040] (Feature 3) Reduce premature wear of the cutting tool 3 caused by a black skin layer (e.g., generated by forging, casting, or rolling) that may occur when the workpiece 1 before cutting is manufactured at a high temperature. Since the black skin layer has a higher hardness than the part (base metal part) below the black skin layer, if the cutting edge of the cutting tool 3 cuts inside the black skin layer, the cutting edge wears faster than when cutting the base metal part. Therefore, by increasing the cutting amount, it is possible to reduce the cutting of the cutting edge inside the black skin layer, thereby reducing premature wear of the cutting tool 3.

[0041] (Feature 4) Prioritize maintaining the quality after finishing by ensuring the finishing allowance over tool wear. When the unevenness amount of the material 1 is too large or the scale layer is too thick, prioritize the processes of Feature 1 and Feature 3 to prevent failure in ensuring the finishing allowance described in Feature 2. In the examples of FIGS. 6 and 7, the relationship between the material contour line 301 and the material contour line to be described later, the contour line 302 moved considering the unevenness amount, and the finishing allowance 303 is shown. In the example of FIG. 6, by prioritizing Feature 1 for the moved contour line 302, the moved contour line 302 has entered the area 305 of the finishing allowance 303, and the finishing allowance cannot be ensured. Therefore, when such a situation is expected to occur, as shown in FIG. 7, the moved contour line 302 in the area 305 is moved out again to the outside of the finishing allowance. Note that 304 in FIGS. 6 and 7 indicates the cutting target contour line.

[0042] <NC Data Generation Process> FIG. 3 is a flowchart showing the NC data generation process. The execution entity of the flowchart can be referred to as the processor 71, the machining path generation device 7, or the machining path generation program 721 as described above. Hereinafter, the machining path generation program 721 will be used as a representative. The start of this process can be considered, for example, as receiving an instruction from the user of the machine tool via the user interface of the machining path generation device 7. More preferably, the machining path generation program 721 preferably has a process of receiving the target finishing allowance and the assumed scale thickness from the user of the machine tool (via the user interface) and storing them in the storage resource 72. More preferably, the machining path generation program 721 can preferably receive the cutting target contour line from a non-volatile memory or another processor system via a peripheral interface or a network interface. When the cutting target contour line is generated from reference NC data (which may include information on the cutting tool), it is preferable that the data can be received in a similar manner. Hereinafter, each step will be described.

[0043] (Step S101) The machining path generation program 721 acquires the material three-dimensional shape of the material 1 and stores it in the storage resource 72 (more specifically, material three-dimensional shape data 731). This acquisition is, for example, one of the following cases. *Measurement is performed using the shape measuring device 4 and shape measuring device 5 shown in Figures 1 and 2. Specifically, while rotating the material 1 fixed to the chuck, the shape measuring devices 4 and 5 measure the distance from the devices to the position of the surface of the material 1 where the measurement light is irradiated. The three-dimensional shape of the material 1 is calculated based on this distance, the rotation angle of the chuck, and the position of the shape measuring device 4 or 5. In this way, it is possible to more directly calculate (i.e., obtain) the three-dimensional shape of the material 1 according to a cylindrical coordinate system with the rotation axis of the chuck as the reference axis. *The shape of the material 1 before it is fixed to the chuck is measured by the shape measuring device 5, and the results are received (i.e., acquired) by the machining path generation program 721. In this case, the three-dimensional shape of the material is typically expressed in the Euclidean coordinate system.

[0044] (Step S102) The machining path generation program 721 calculates the amount of material unevenness from the material three-dimensional shape (stored in the material three-dimensional shape data 731). A specific example of the calculation method is as explained in the data chapter. The program 731 stores the calculated amount of material unevenness in material unevenness amount data 737.

[0045] (Step S103) The machining path generation program 721 generates a material contour line from the material 3D shape (stored in the material 3D shape data 731). A specific example of the generation method is as explained in the data chapter. The program 731 stores the generated material contour line in the material contour line data 736.

[0046] (Step S104) The machining path generation program 721 moves the material contour line toward the inside of the material based on the material unevenness amount (stored in the material unevenness amount data 737). As described above, the inside of the material means the direction toward the rotation axis of the chuck in the case of the outer surface, the direction away from the rotation axis of the chuck in the case of the inner surface, and the direction toward the upper surface of the material in the case of the upper surface of the material. Examples of this movement are as follows. *In the case of side surfaces, the movement is performed by subtracting (in the case of outer surfaces; if it is an inner surface, adding) the unevenness amount (which exists for each height cz) from the radial distance ρ (representative radial distance) of the material contour line for each height cz so that the movement is in the material's inner direction. Note that calculations may be performed on the unevenness amount before addition or subtraction to ensure a margin.

[0047] (Step S105) The machining path generation program 721 determines whether the workpiece contour line after movement is included in the finishing allowance. Note that the region of the finishing allowance is specified, for example, as follows. *The area between the radial distance ρ of the cutting target contour line (stored in the cutting target contour line data 732) and the contour line obtained by moving the radial distance ρ to the outside of the material by the target finishing allowance thickness (hereinafter referred to as the finishing allowance boundary) is recognized as the finishing allowance.

[0048] (Step S106) The machining path generation program 721 re-moves the part of the workpiece contour line that has been moved and is included in the finishing allowance, outside the finishing allowance. A typical example of re-moving is to move the part of the workpiece contour line (meaning the part that was included in the finishing allowance) onto the boundary of the finishing allowance, but it may also be moved further outside the workpiece.

[0049] (Step S107) The machining path generation program 721 determines whether at least a portion of the material contour line after the movement in step S105 or step S106 (including after re-movement) passes through the black skin layer. It is possible to identify the black skin layer region by, for example, identifying the region from the surface of the three-dimensional shape of the material 1 to a boundary (hereinafter referred to as the black skin layer boundary 202) obtained by moving the surface inward of the material by the estimated black skin thickness (stored in the estimated black skin thickness data 734) as the black skin layer. It is also possible that the estimated black skin thickness does not have to be a fixed constant. For example, the thickness may be different on the outer surface, inner surface, and top surface, or it may be specified as a distribution on the surface of the material 1.

[0050] (Step S108) The machining path generation program 721 re-moves the part of the material contour line that is included in the black skin layer after the movement to outside the black skin layer. Note that a typical example of re-moving is to move the part of the material contour line (meaning the part that was included in the black skin layer) onto the black skin layer boundary 202, but it may also be moved further outside the material.

[0051] (Step S109) The machining path generation program 721 generates a machining path for surface cutting based on the workpiece contour line after movement (including re-movement) in S104 to S108. The generation of the machining path is, for example, the generation of a G-code that indicates a straight line or curve that traces the workpiece contour line after movement. Note that the generated machining path is typically treated as part of rough machining, but this is not necessarily the case.

[0052] (Step S110) The machining path generation program 721 generates a machining path that cuts the area from the workpiece contour line after movement to the finishing allowance boundary (provided that this area remains). The machining path generation program 721 also generates a machining path that cuts from the finishing allowance boundary to the cutting target contour line. In order to generate this path, a CAM tool may be executed by the machining path generation device 7. As another generation example, G-code may be repeatedly generated that traces a line obtained by moving the workpiece contour line after movement by the maximum cutting depth of the rough machining cutting tool 3 toward the inside of the workpiece, within a range that does not exceed the finishing allowance boundary. The same applies to finish machining.

[0053] (Step S111) The machining path generation program 721 generates generated NC data including the machining paths generated in steps S109 and S110, and stores the generated NC data in the storage resource 72. This completes the description of the flowchart of the NC data generation process.

[0054] <Variations> This embodiment has been described above. The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention. For example, a sub-combination of the machining system 10, such as a machining system 10 that does not include the machine tool 2, is also an embodiment of the present invention. Other variations are as follows. *The data indicating the machining path may be something other than NC data (NC program). Therefore, the NC data generation program may also be called a machining path generation program. *In the flowchart shown in Figure 3, the machining paths for rough machining and finish machining (and rough machining terms) are included in one NC data, but they can also be generated as separate NC data. *In the above example, a combination of rough machining and finish machining was explained, but it is also possible to generate a machining path without finish machining. Furthermore, the processing explained for rough machining can be applied to finish machining, rough machining, or other machining. *The finishing allowance boundary can be a line that is thickened by the target cutting contour line by the target finishing allowance thickness. *In the above example, the unevenness amount of the material unevenness information was explained on the assumption that it has a specific numerical value for each height cz (for example, every 1 mm), but it may be thinned out to reduce the amount of data, or interpolation processing may be performed. *The jig (fixing jig) for fixing the material 1 may be other than a chuck. For example, it may be a holder. *The machining path may indicate any of the path of the cutting tool 3, the path of the cutting tip of the cutting tool 3, or the path of the tool post. *The machining path may be able to specify the y-axis. The generated NC data may include tool change instructions for using different types of cutting tools 3 for rough machining and finish machining. *Storage of the shape contour line, material contour line, and material unevenness amount in the storage resource 72 may be omitted. [Explanation of symbols]

[0055] 1 Material, 2 Machine tool, 3 Cutting tool, 4 Measuring equipment, 5 Measuring equipment, 6 Control device, 7 Machining path generation device, 10 Machining system, 71 Processor, 72 Memory resource

Claims

1. one or more processors; One or more storage resources storing a machining path generation program; A processor system having: By executing the machining path generation program, the processor: (1) Obtain the three-dimensional shape of the material; (2) calculating, from the three-dimensional shape of the material, unevenness information of the material, which indicates the difference between the outer surface convexity, which is the most protruding position on the outer surface of the material, and the outer surface concavity, which is the most recessed position on the outer surface, and the difference between the inner surface convexity, which is the position on the inner surface of the material closest to the rotation axis, and the inner surface concavity, which is the most recessed position on the inner surface; (3) generating a material contour line representing a shape contour line of the material from the three-dimensional shape of the material; (4) moving the material contour line to the inside of the material based on the unevenness information; (5) generating a machining path for cutting the surface of the material based on the moved material contour line; A system characterized by

2. 10. The system of claim 1, (3) The generation of the material contour line is performed by reducing the dimension of the three-dimensional shape of the material to a two-dimensional shape formed by using the height cz as a constant and the radial distance ρ and the azimuth angle φ of the cylindrical coordinate system as variables. A system including at least:

3. 10. The system of claim 1, The system further comprises a user interface or a network interface; The processor: (6) receiving a target stock thickness via the user interface or the network interface; (7) obtaining a cutting target contour line indicating a target contour after cutting of the material; (8) Recognizing a finishing allowance area based on the cutting target contour line and the target finishing allowance thickness; (9) The workpiece contour line or a part thereof that is included in the finishing allowance area and that has been moved in (4) is moved again to outside the finishing allowance area. A system characterized by:

4. 4. The system of claim 3, The processor: (10) receiving an estimated black skin thickness via the user interface or the network interface; (11) Recognizing the black skin layer based on the three-dimensional shape of the material and the estimated black skin thickness; (12) Removing the material contour line or a part thereof in (4) or (9) included in the black skin layer to the outside of the black skin layer. A system characterized by:

5. 5. A system according to any one of claims 1 to 4, The system further comprises a machine tool. system.

6. The processor of the processor system (1) Obtain the three-dimensional shape of the material; (2) calculating, from the three-dimensional shape of the material, unevenness information of the material, which indicates the difference between the outer surface convexity, which is the most protruding position on the outer surface of the material, and the outer surface concavity, which is the most recessed position on the outer surface, and the difference between the inner surface convexity, which is the position on the inner surface of the material closest to the rotation axis, and the inner surface concavity, which is the most recessed position on the inner surface; (3) generating a material contour line representing a shape contour line of the material from the three-dimensional shape of the material; (4) moving the material contour line to the inside of the material based on the unevenness information; (5) generating a machining path for cutting the surface of the material based on the moved material contour line; A machining path generation method characterized by the above.

7. 7. The machining path generation method according to claim 6, (3) The generation of the material contour line is performed by reducing the dimension of the three-dimensional shape of the material to a two-dimensional shape formed by using the height cz as a constant and the radial distance ρ and the azimuth angle φ of the cylindrical coordinate system as variables. A machining path generation method including at least the above.

8. The machining path generation method according to claim 7, The processor system further comprises a user interface or a network interface; The processor: (6) receiving a target stock thickness via the user interface or the network interface; (7) obtaining a cutting target contour line indicating a target contour after cutting of the material; (8) Recognizing a finishing allowance area based on the cutting target contour line and the target finishing allowance thickness; (9) The workpiece contour line or a part thereof that is included in the finishing allowance area and that has been moved in (4) is moved again to outside the finishing allowance area. A machining path generation method comprising:

9. The machining path generation method according to claim 8, The processor: (10) receiving an estimated black skin thickness via the user interface or the network interface; (11) Recognizing the black skin layer based on the three-dimensional shape of the material and the estimated black skin thickness; (12) The material contour line or a part thereof included in the black skin layer and moved in (4) or (9) is moved again to the outside of the black skin layer. A machining path generation method comprising:

10. 10. The machining path generation method according to claim 6, the processor system is connected to a machine tool; Machining path generation method.

11. A program for causing the processor system to execute the method according to any one of claims 6 to 10.

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