Numerical controller for machine tool

Abstract

The invention provides a numerical controller for a machine tool. The numerical controller generates both a cutting operation in a forward direction and a cutting operation in a return direction. A numerical controller of a machine tool rotates a tool and a workpiece relative to each other, reciprocates the tool and the workpiece relative to each other, and performs cutting of the workpiece by both a forward cutting operation and a return cutting operation, the numerical controller including: a removal region input unit that analyzes a cutting program; reading the shape of a removal region of the workpiece removed by the cutting process; a machining condition input unit that reads machining conditions for cutting machining, the machining conditions including at least a cutting amount of the tool during a cutting operation in the forward direction and a cutting amount of the tool during a cutting operation in the return direction; and an operation generation unit that generates a cutting operation in the forward path direction and a cutting operation in the return path direction on the basis of the shape of the removal region and the machining conditions such that the tool intersects the uncut portion in the removal region, and the intersection amount does not exceed the cutting amount in the forward path direction and the cutting amount in the return path direction in the machining conditions.

Description

Technical Field

[0001] The invention relates to a numerical control device for a machine tool. Background Art

[0002] A control technology for a machine tool is known, which performs cutting of a workpiece by rotating the workpiece and moving the tool relative to the workpiece according to a processing program. In such a technology, it is known to repeatedly move the tool back and forth relative to the workpiece, for example, to perform cutting in the forward direction in multiple times. For example, refer to Patent Document 1.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-288563 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Like this, in the technology of cutting workpiece several times, it is expected to shorten the processing time. About this, it is thought that not only the cutting action of the outward direction but also the cutting action of the return direction is carried out.

[0008] However, in a numerical control device, in order to realize both the cutting action in the forward direction and the cutting action in the return direction, it is necessary to specify the position or movement amount of the cutting action in the forward direction and the cutting action in the return direction in the processing program, based on the cut-in amount of each other. It is difficult to manually create such a processing program, and the more complex the shape after processing, the higher the difficulty. In addition, if programming auxiliary software such as CAM is used, the processing program can be created relatively simply, but it costs the cost of introducing such software. Therefore, it is desired to suppress the cost of introducing programming auxiliary software, and generate both the cutting action in the forward direction and the cutting action in the return direction in the numerical control device.

[0009] Means for solving problems

[0010] A method of a numerical control device for a machine tool disclosed in the present invention causes a tool and a workpiece to rotate relative to each other, and causes the tool and the workpiece to reciprocate relative to each other, and performs cutting processing on the workpiece by both cutting actions in a forward direction and cutting actions in a return direction, wherein the numerical control device for the machine tool comprises: a removal area input unit, which analyzes the program of the cutting processing and reads the shape of the removal area of ​​the workpiece removed by the cutting processing; a processing condition input unit, which reads the processing conditions of the cutting processing, and the processing conditions at least include the cutting amount of the tool in the cutting action in the forward direction and the cutting amount of the tool in the cutting action in the return direction; and an action generation unit, which generates the cutting action in the forward direction and the cutting action in the return direction according to the shape of the removal area and the processing conditions, so that the tool intersects with the uncut part in the removal area, and the intersection amount does not exceed the cutting amount in the forward direction and the cutting amount in the return direction in the processing conditions.

[0011] Effects of the Invention

[0012] According to one embodiment, the cost of introducing software can be suppressed, and both the cutting operation in the forward direction and the cutting operation in the return direction can be generated in the numerical control device, thereby shortening the machining time. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing an example of a numerical control device for a machine tool according to the present embodiment.

[0014] Figure 2A This is an example of a machining program for cutting an arbitrary shape including a straight line and a curved line.

[0015] Figure 2B yes Figure 2A An example of the description of the machining program shown.

[0016] Figure 3A Yes means Figure 2A The cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z).

[0017] Figure 3B Yes means Figure 2A The cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z).

[0018] Figure 4A This is an example of a machining program for cutting an arbitrary shape including a straight line and a curved line.

[0019] Figure 4B yes Figure 4A An example of the description of the machining program shown.

[0020] Figure 5A This is an example of a machining program for cutting an arbitrary shape including a straight line and a curved line.

[0021] Figure 5B This is an example of a table of tool identification information and processing conditions.

[0022] Fig. 6A This is a diagram showing an example of the cutting motion in the outward direction and the cutting motion in the return direction of the tool by the motion generation unit.

[0023] Figure 6B This is a diagram showing an example of the cutting motion in the outward direction and the cutting motion in the return direction of the tool by the motion generation unit.

[0024] Figure 6C This is a diagram showing an example of the cutting motion in the outward direction and the cutting motion in the return direction of the tool by the motion generation unit.

[0025] Fig. 7A This is a diagram showing an example of an approach motion by the motion generation unit.

[0026] Figure 7B This is a diagram showing an example of an approach motion by the motion generation unit.

[0027] Fig. 8A This is a diagram showing an example of a switching operation between a cutting operation in a forward direction and a cutting operation in a return direction by an operation generating unit.

[0028] Figure 8B This is a diagram showing an example of a switching operation between a cutting operation in a forward direction and a cutting operation in a return direction by an operation generating unit.

[0029] Fig.9A This is a diagram showing an example of a cut-out operation along a removal area by the operation generating unit.

[0030] Fig. 9B This is a diagram showing an example of a cut-out operation along a removal area by the operation generating unit.

[0031] Fig.10 This is a diagram showing an example of a retreat motion and an approach motion after a cut-out motion by a motion generation unit.

[0032] Fig.11A This is a diagram showing an example of a cut-out motion and a cut-in motion by a motion generation unit.

[0033] Fig. 11BThis is a diagram showing an example of a cut-out motion and a cut-in motion by a motion generation unit.

[0034] Fig. 12A This is a diagram showing an example of the retreat motion and approach motion at the end of processing by the motion generation unit.

[0035] Fig. 12B This is a diagram showing an example of the retracting motion and approaching motion performed by the motion generating unit when processing is completed.

[0036] Fig.13A This is an example of a machining program for performing cutting processing on a shape including only a straight line contour, in other words, a rectangular removal area.

[0037] Fig. 13B This is an example of a machining program for performing cutting processing on a shape including only a straight line contour, in other words, a removal area including a tapered shape (right triangle shape) in a rectangular shape.

[0038] Fig. 13C This is an example of a machining program for performing cutting processing on a shape including only a straight line contour, in other words, removing a tapered (right-angled triangle) shape.

[0039] Fig.13D yes Figures 13A to 13C An example of the description of the machining program shown.

[0040] Fig.14A Yes means Fig.13A The cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z).

[0041] Fig. 14B Yes means Fig.13A The cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z).

[0042] Fig. 14C Yes means Fig.13A The cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z).

[0043] Fig.14D Yes means Fig. 13B The cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z).

[0044] Fig.14E Yes means Fig. 13CThe cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z).

[0045] Fig.15 It is a diagram showing an example of the cutting motion in the outward direction and the cutting motion in the return direction of the tool based on the motion generation unit of the modified example of the present embodiment.

[0046] Fig.16 It is a diagram showing an example of the cutting motion in the outward direction and the cutting motion in the return direction of the tool based on the motion generation unit of the modified example of the present embodiment.

[0047] Fig.17 It is a diagram showing an example of the rotational motion of the tool and the workpiece, the cutting motion in the forward direction, and the cutting motion in the return direction according to a modification of the present embodiment.

[0048] Fig.18A This is a machining program according to a modified example of the present embodiment, and is an example of a machining program for performing cutting machining of a shape having a contour including only one curved line.

[0049] Fig.18B Yes means Fig.18A The cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z). DETAILED DESCRIPTION

[0050] Hereinafter, an example of an embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in each of the drawings, the same or corresponding parts are denoted by the same reference numerals.

[0051] (First Embodiment)

[0052] Figure 1 This is a diagram showing an example of a numerical control device for a machine tool according to the present embodiment. Figure 1 The numerical control device 10 shown controls the operation of the machine tool 20 , specifically, controls the cutting operation of the workpiece W by the tool T, according to the machining program 5 .

[0053] Examples of the workpiece W include cylindrical, cylindrical, conical, or truncated cone-shaped workpieces. Figure 1 In the drawings described later, the central axis of the workpiece W, which is the rotation axis of the workpiece W, is defined as the Z axis, and an axis perpendicular to the Z axis is defined as the X axis.

[0054] The machine tool 20 performs cutting processing on the workpiece W using a tool T. Specifically, the machine tool 20 rotates the workpiece W with the Z axis as the rotation axis and reciprocates the tool T along the Z axis or along the combined direction of the Z axis and the X axis, thereby performing cutting processing on the workpiece W. The machine tool 20 performs cutting processing on the workpiece W by both cutting action in the outward direction (e.g., -Z direction) and cutting action in the return direction (e.g., +Z direction). As such a tool T, for example, a tool having two blades T1 and T2 can be cited.

[0055] The shape of the machine tool 20 along the Z-axis direction is not limited to a straight line, and an arc-shaped workpiece can also be processed. In addition, the machine tool 20 is not limited to the outer peripheral surface of the workpiece, and the inner peripheral surface of a cylindrical workpiece can also be processed.

[0056] The numerical control device 10 controls the rotation of the workpiece W and controls the movement of the tool tip T3 of the tool T. The control of the movement of the tool tip T3 of the tool T is described in detail below. The numerical control device 10 includes a removal area input unit 12, a machining condition input unit 14, an action generation unit 16, and a storage unit 18.

[0057] The numerical control device 10 (excluding the storage unit 18) is composed of a calculation processor such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or an FPGA (Field-Programmable Gate Array). The various functions of the numerical control device 10 (excluding the storage unit 18) are realized by executing, for example, predetermined software (programs) stored in the storage unit 18. The various functions of the numerical control device 10 (excluding the storage unit 18) can be realized by the cooperation of hardware and software, or can be realized only by hardware (electronic circuit).

[0058] The storage unit 18 is constituted by, for example, a memory such as a ROM (Read Only Memory), a HDD (Hard Disk Drive), or a SSD (Solid State Drive). The storage unit 18 stores predetermined software (programs) for executing various functions of the numerical controller 10 described above.

[0059] In the present embodiment, the machining program 5 includes the shape of the removal area of ​​the workpiece W to be removed by cutting (in other words, the contour shape of the workpiece W after cutting) and the machining conditions of the cutting. The removal area input unit 12 analyzes the machining program 5 and reads the shape of the removal area of ​​the workpiece W. The machining condition input unit 14 analyzes the machining program 5 and reads the machining conditions of the cutting. The machining program 5, the removal area input unit 12, and the machining condition input unit 14 are described in detail below.

[0060] Figure 2A This is an example of a machining program for cutting an arbitrary shape including a straight line and a curved line. Figure 2B yes Figure 2A An example of the description of the processing program shown. Figure 3A as well as Figure 3B Yes means Figure 2A The cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z).

[0061] like Figure 2A , Figure 2B as well as Figure 3A As shown,

[0062] G130 is a command for generating a reciprocating cutting motion parallel to the Z axis by designating a plurality of movement blocks N100 to N104.

[0063] PS_ is the initial serial number of the moving program block (moving program block N100 from A to B).

[0064] PE_ is the last serial number of the mobile block (→C's mobile block N104).

[0065] U_ is the finishing allowance for finishing, which is the finishing allowance in the X direction.

[0066] W_ is the finishing allowance for finishing, which is the finishing allowance in the Z direction.

[0067] G00 is a positioning command.

[0068] G01 is a command for cutting feed based on linear interpolation.

[0069] G02 is a command for cutting feed based on clockwise circular interpolation (the radius of the arc is specified by R).

[0070] like Figure 2A as well as Figure 3A As shown,

[0071] The movement block N100 represents the movement of the positioning from the movement start point A (Z=20.0, X=15.0) to the point B (Z=20.0, X=5.0).

[0072] The movement block N101 represents the movement of the cutting feed based on linear interpolation from point B (Z=20.0, X=5.0) to the position Z=16.0 in the Z direction.

[0073] The moving block N102 indicates a further movement of the cutting feed based on the clockwise circular interpolation to the position Z=13.0 in the Z direction and the circular radius R=3.0.

[0074] The movement block N103 indicates further movement to the position (Z=10.0, X=10.0) by cutting feed based on linear interpolation.

[0075] The movement block N104 indicates a further movement of the cutting feed by linear interpolation to the position X=15.0 in the X direction, that is, the movement end point C (Z=10.0, X=15.0).

[0076] In addition, the coordinate value of the X axis will not decrease between BC.

[0077] Thus, the moving program blocks N100 to N104 represent the contour shape of the removal area R of the workpiece W specified by one or more straight lines or curved lines, in other words, the contour shape of the workpiece W after cutting. Furthermore, when there is a designation of the finishing allowance (U, W), the moving program blocks N100 to N104 represent the contour shape of the removal area R of the workpiece W of the finishing shape, in other words, the contour shape of the workpiece W after cutting. Thus, the machining program includes the contour shape of the removal area R of the workpiece W removed by cutting, in other words, the contour shape of the workpiece W after cutting.

[0078] At this time, the removal area input unit 12 analyzes the machining program and reads the shape of the removal area R of the workpiece W to be removed by cutting from the contour shape of the removal area in the machining program. Figure 2A and Figure 3A When the G130 instruction is shown, the removal area input unit 12 reads the interior of the area surrounded by the points ABC from the moving blocks N100 to N104 as the removal area R. Alternatively, Figure 2A and Figure 3B As shown, when there is a designation of finishing allowance (U, W), the removal area input unit 12 further reads the finishing allowance (U, W) from the machining program and moves the read removal area R in parallel in the X direction and the Z direction by the amount of the finishing allowance.

[0079] Figure 4A This is an example of a machining program for cutting an arbitrary shape including a straight line and a curved line. Figure 4B yes Figure 4A An example of the description of the machining program shown in FIG. Figure 4A and Figure 4B As shown, the movement program blocks N100 to N104 may also be provided as subroutines.

[0080] PP_ is the subroutine number that specifies the move block (finishing shape).

[0081] M99 indicates the end of the subroutine (return to the main program).

[0082] Refer again Figure 2A and Figure 2B , the machining program includes the machining conditions for cutting.

[0083] D1_ is the cutting amount of the tool T in the cutting action in the outward direction (A→C direction), and D2_ is the cutting amount of the tool T in the cutting action in the return direction (C→A direction).

[0084] F1_ is the feed speed of the tool T in the cutting action in the outward direction (A→C direction), and F2_ is the feed speed of the tool T in the cutting action in the return direction (C→A direction).

[0085] E_ is the cutting direction at the end of processing. For example, in E0, the cutting direction at the end of processing is not specified. For example, in E1, the cutting direction at the end of processing is specified as the outward direction. In addition, for example, in E2, the cutting direction at the end of processing is specified as the return direction.

[0086] RR_ is the amount of retraction of tool T after the cutting action.

[0087] TY_ is the designation of the cutting action or the cutting action in the cutting action. For example, in TY0, the cutting action or the cutting action along the outer periphery of the removal area R is designated. For example, in TY1, the cutting action or the cutting action based on the line segment is designated. In addition, in TY2, for example, the cutting action or the cutting action based on the arc is designated.

[0088] UD_ is the amount of overrun during the cut-out action.

[0089] At this time, the processing condition input unit 14 analyzes the processing program and reads the processing conditions of the cutting process. Figure 2A When the G130 command is issued, the machining condition input unit 14 reads the cutting amount of the tool T in the cutting action in the forward direction from address D1, and reads the cutting amount of the tool T in the cutting action in the return direction from address D2. In addition, the machining condition input unit 14 reads the feed speed of the tool T in the cutting action in the forward direction from address F1, and reads the feed speed of the tool T in the cutting action in the return direction from address F2. In addition, the machining condition input unit 14 reads the cutting direction at the end of machining from address E.

[0090] In addition, the processing condition input unit 14 reads the amount of tool T retracted after the cutting action from the address RR. In addition, the processing condition input unit 14 reads the designation of the cut-out action or the cut-in action in the cutting action and the type of path from the address TY. For example, at TY0, the processing condition input unit 14 reads the cut-out action or the cut-in action of the straight path or the curved path along the periphery of the removal area R. For example, at TY1, the processing condition input unit 14 reads the cut-out action or the cut-in action of any straight path (line segment) in the plane formed by the Z axis and the X axis. In addition, for example, at TY2, the processing condition input unit 14 reads the cut-out action or the cut-in action of any curved path (arc) in the plane formed by the Z axis and the X axis. In addition, the processing condition input unit 14 reads the excess amount of the cut-out action from the address UD.

[0091] Furthermore, the machining conditions of the cutting machining may be stored in advance in the storage unit 18 . Figure 5A This is an example of a machining program for cutting an arbitrary shape including a straight line and a curved line. Figure 5B is an example of a table of tool identification information and processing conditions. Figure 5B As shown in FIG. 1 , the storage unit 18 stores information in a table format in which the identification information of the tool and its processing conditions (D1, D2, F1, F2, E, TY, UD) are associated. Figure 5A As shown, the machining program 5 includes a designation T_ of the identification information of the tool.

[0092] At this time, the machining condition input unit 14 may analyze the machining program and read the machining conditions corresponding to the identification information of the tool from the storage unit 18. Thus, the machining program 5 can be simplified.

[0093] Next, the action generation unit 16 is described. The action generation unit 16 generates a reciprocating cutting action based on the removal area read by the removal area input unit 12 and the processing conditions read by the processing condition input unit 14. Specifically, the action generation unit 16 generates a cutting action in the outward direction and a cutting action in the return direction of the tool T relative to the workpiece W, so that the tool T intersects with the uncut portion in the removal area R, and the amount of intersection does not exceed the amount of tool penetration in the outward direction and the amount of tool penetration in the return direction of the processing conditions. The cutting action in the outward direction and the cutting action in the return direction are straight line paths parallel to the Z axis, and are paths in opposite directions to each other in the Z axis direction.

[0094] Figure 6A to Figure 6C 1 is a diagram showing an example of a cutting action in the outward direction and a cutting action in the return direction of a tool by an action generating unit. Figure 6A to Figure 6C In the figure, the solid line represents the cutting action in the forward direction, the dotted line represents the cutting action in the return direction, d1 represents the cutting amount of the cutting action in the forward direction, and d2 represents the cutting amount of the cutting action in the return direction.

[0095] For example, Fig. 6A As shown, when the designated cutting direction (E) at the end of processing is the forward direction, the action generating unit 16 generates the cutting action in the forward direction (solid line) and the cutting action in the return direction (dashed line) alternately from the bottom with the cutting amount d1 of the cutting action in the forward direction and the cutting amount d2 of the cutting action in the return direction.

[0096] Another example Figure 6B As shown, when the designated cutting direction (E) at the end of processing is the loop direction, the action generating unit 16 generates the cutting action in the loop direction (dashed line) and the cutting action in the forward direction (solid line) alternately from the bottom with the cutting amount d2 of the cutting action in the loop direction and the cutting amount d1 of the cutting action in the forward direction.

[0097] Or Figure 6C As shown, when the cutting direction (E) at the end of processing is not specified, the action generating unit 16 can generate the cutting action in the forward direction (solid line) and the cutting action in the return direction (dashed line) alternately from the top with the cutting amount d1 of the cutting action in the forward direction and the cutting amount d2 of the cutting action in the return direction.

[0098] When the cutting amount of the cutting action exceeds the removal area R, in other words, when the tool does not intersect the uncut portion in the removal area, the action generation unit 16 ends the creation of the cutting action. Figure 6C As shown, when the cutting amount of the cutting action exceeds the removal area R, the action generation unit 16 modulates the cutting amount of the last generated cutting action so as not to exceed the removal area R. In addition, when the cutting amount of the cutting action exceeds the removal area R, the action generation unit 16 may modulate the excess amount so as to be divided and distributed to a plurality of cutting actions and subtracted from the cutting amounts of the plurality of cutting actions.

[0099] Fig. 7A as well as Figure 7B is a diagram showing an example of an approach action by the action generating unit. Fig. 7A As shown in FIG. 1 , when the Z coordinate of the intersection point (white circle) of the tool T and the uncut portion of the removal area R at the start of machining is the same as the Z coordinate of the action start point A, the approach action is not required. Figure 7B As shown, when the Z coordinate of the intersection (white star) of the tool T and the uncut part of the removal area R at the start of processing is different from the Z coordinate of the action starting point A, the action generation unit 16 can generate an approach action (positioning action, rapid feed action) from the processing start point A to the intersection in the Z direction.

[0100] Fig. 8A and Figure 8B1 is a diagram showing an example of a switching action between a cutting action in the outward direction and a cutting action in the return direction by an action generating unit. Fig. 8A and Figure 8B In FIG. 1 , the white circle indicates the start position of the cutting action (solid line) in the forward direction of the removal area R, and the black circle indicates the end position of the cutting action (solid line) in the forward direction. Fig. 8A and Figure 8B In FIG. 1 , the start position of the cutting action (dashed line) in the loop direction among the positions on the periphery of the removal area R is indicated by a white star, and the end position of the cutting action (dashed line) in the loop direction is indicated by a black star.

[0101] like Fig. 8A and Figure 8B As shown, the action generation unit 16 generates an approach action or a cutting action along the periphery of the removal area R toward the starting position (white circle) of the cutting action (solid line) in the forward direction or the starting position (white star) of the cutting action (dashed line) in the return direction. In addition, the action generation unit 16 generates an approach action or a cutting action along the periphery of the removal area R so as to connect the end position (black circle) of the adjacent cutting action (solid line) in the forward direction and the starting position (white star) of the cutting action (dashed line) in the return direction. In addition, the cutting action refers to the action of the tool T toward the direction approaching the uncut portion of the removal area R.

[0102] When the A→B moving program block is a rapid feed instruction, the action according to A→B can be an approach action (positioning action, rapid feed action). On the other hand, when the A→B moving program block is a cutting feed instruction, the action according to A→B can be a cut-in action (cutting feed action). In addition, when the B→C moving program block is a cutting feed instruction, the action according to B→C can be a cut-in action (cutting feed action).

[0103] Fig.9A and Fig. 9B FIG. 1 is a diagram showing an example of a cut-out action along a removal area by an action generation unit. Fig.9A As shown, in order to eliminate cutting residues, Fig. 9BAs shown, the action generation unit 16 may include a cutting action (TY) along the periphery of the removal area R in the cutting action in the outward direction (solid line) and the cutting action in the return direction (dashed line). The cutting action refers to the action of the tool T moving in the direction of the uncut portion away from the removal area R. In addition, the cutting action may also include an overrun action (UD) along the periphery of the removal area R. The overrun action refers to the action of the tool T further exceeding the uncut portion of the removal area R after reaching it. At this time, the cutting action is performed again by the opposite action of the cutting action.

[0104] Fig.10 1 is a diagram showing an example of a retreat action and an approach action after a cut-out action by an action generation unit. Fig.10 As shown, the action generation unit 16 may include a retracting action (RR) and an approaching action after the cutting action. The retracting action refers to the action of the tool T moving in a direction away from the workpiece W. Thus, the interference between the tool T and the workpiece W can be suppressed. In addition, the occurrence of a tool mark on the workpiece W can be prevented.

[0105] Fig.11A and Fig. 11B 1 is a diagram showing an example of a cut-out action and a cut-in action by an action generation unit. Fig.11A As shown, the action generation unit 16 can include the cutting action (solid line) in the outward direction and the cutting action (dashed line) in the return direction, and the cutting action (TY) of any straight line path (line segment) in the plane formed by the Z axis and the X axis. Fig. 11B As shown, the action generation unit 16 can include the cutting action and the cutting action (TY) of any curved path (arc) in the plane formed by the Z axis and the X axis in the cutting action in the outward direction (solid line) and the cutting action in the return direction (dashed line). Thus, the cutting load of the tool in the cutting action can be reduced.

[0106] In addition, similar to the above, the action generation unit 16 may include a retracting action (RR) and an approaching action after the cut-out action.

[0107] Fig. 12A and Fig. 12B 1 is a diagram showing an example of a retreat action and an approach action at the end of processing by the action generation unit. Fig. 12A and Fig. 12B As shown, when the cutting amount of the cutting action exceeds the removal area R, in other words, when the tool does not intersect the uncut portion in the removal area, the action generation unit 16 can generate a retraction action (RR) and an approach action. Fig. 12A As shown in FIG. 1 , when the cut-out action is not included, the action generation unit 16 can generate the retreat actions a, b, and c after the processing action is completed. Fig. 12BAs shown, when the cut-out action is included, the action generation unit 16 can generate the retreat actions a, b, and c after the cut-out action. The retreat action a is, for example, cutting feed. In addition, the retreat actions b and c are, for example, rapid feed returning to the action start point A.

[0108] As described above, according to the numerical control device of the first embodiment, in addition to the cutting operation in the forward direction, the cutting operation in the return direction is also performed, so the machining time can be shortened.

[0109] In addition, according to the numerical control device of the first embodiment, the machining program only specifies the shape of the removal area, in other words, the shape after machining. According to the machining program, the position or movement amount of the cutting action in the forward direction and the cutting action in the return direction can be generated based on the cut-in amount of each other in the forward direction and the return direction. As a result, the cost of introducing programming support software can be suppressed without using relatively effective programming support software such as CAM, and both the cutting action in the forward direction and the cutting action in the return direction can be generated in the numerical control device.

[0110] (Second Embodiment)

[0111] In the first embodiment, the cutting process of an arbitrary shape of a contour including straight lines and curves is described. In the second embodiment, the cutting process of a contour shape including only straight lines, in other words, a rectangular removal area, a rectangular removal area including a cone (right triangle), or a cone (right triangle) removal area is described.

[0112] The structure of the numerical control device of the second embodiment is Figure 1 The numerical control device of the second embodiment has the same structure as the numerical control device of the first embodiment shown in FIG. Figure 1 Compared with the numerical control device of the first embodiment shown, the functions and operations of the removal area input unit 12, the processing condition input unit 14, and the operation generation unit 16 are different.

[0113] Fig.13A This is an example of a machining program for performing a cutting process on a contour shape including only straight lines, in other words, a rectangular removal area. Fig. 13B This is an example of a machining program for cutting a contour shape containing only straight lines, in other words, a rectangular shape including a tapered (right-angled triangle) removal area. Fig. 13C This is an example of a machining program for performing a cutting process on a contour shape including only straight lines, in other words, a removal area of ​​a tapered shape (right triangle shape). Fig.13D yes Figures 13A to 13C An example of the description of the processing program shown. Figures 14A to 14C Yes means Fig.13A The shape of the removal area shown in the machining program shown and the cross-sectional view of a part of the contour shape of the machined workpiece (the upper half of the rotation axis Z), Fig.14D Yes means Fig. 13B The shape of the removal area shown in the machining program shown and the cross-sectional view of a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z), Fig.14E Yes means Fig. 13C The cross-sectional view shows the shape of the removal area shown in the machining program and a part of the contour shape of the workpiece after machining (the upper half of the rotation axis Z).

[0114] like Fig.13A , Fig.13D as well as Fig.14A As shown,

[0115] G120 is a command that generates a reciprocating cutting motion parallel to the Z axis by specifying a rectangular area.

[0116] X_ is the X-axis coordinate value (position) of point D located at the diagonal of the action starting point A, and Z_ is the Z-axis coordinate value (position) of point D.

[0117] U_ is the change amount (movement amount) in the X-axis direction from the action start point A to point D (in other words, point B), and W_ is the change amount (movement amount) in the Z-axis direction from the action start point A to point D (in other words, point C).

[0118] In addition, the X-axis coordinate value and the Z-axis coordinate value of the operation start point A are known from the shape of the workpiece W before machining which is stored in advance.

[0119] In this way, the machining program includes the contour shape (rectangular shape) of the removal area R of the workpiece W to be removed by the cutting machining, in other words, the contour shape of the workpiece W after the cutting machining.

[0120] At this time, the removal area input unit 12 analyzes the machining program and reads the shape of the removal area R of the workpiece W to be removed by cutting from the contour shape (rectangular shape) of the removal area in the machining program. Fig.13A and Fig.14A When the G120 command is shown, the removal area input unit 12 reads the inside of the rectangular shape ABDC as the removal area R based on the position (X, Z) of the point D located at the diagonal of the action start point A or the movement amount (U, W) from the action start point A to the point D. In addition, the position of the action start point A is known based on the raw material shape of the workpiece W before cutting processing which is stored in advance.

[0121] In the second embodiment, the address TY for designating the cutting-out operation or the cutting-in operation includes the designation of the finishing allowance, instead of the address (U, W) in the first embodiment.

[0122] The removal area input unit 12 can further read the finishing allowance (TY) from the machining program so that the removal area does not include the finishing allowance. Fig.13A , Fig. 14B as well as Fig. 14C When the G120 command is shown, the removal area input unit 12 sets the area surrounded by a figure having three points, namely, point D and two points E and F separated from point D by a predetermined distance d in the X and Z directions, as the finishing allowance.

[0123] In the address (TY) related to the finishing allowance, when the tens digit is 1, the specified distance d is set as the command value of the cutting amount D1 in the cutting action in the forward direction, and when the tens digit is 2, the specified distance d is set as the command value of the cutting amount D2 in the cutting action in the return direction. In addition, when the ones digit of the address (TY) related to the finishing allowance is 1, as Fig. 14B As shown in , the shape of the finishing allowance is set to the inside of the triangular shape DEF. On the other hand, when the unit digit of the address (TY) related to the finishing allowance is 2, as shown in Fig. 14C As shown, the shape of the finishing allowance is set to be a region surrounded by line segments DE, DF and arc EF.

[0124] In addition, if Fig. 13B , Fig.13D as well as Fig.14D As shown, the processing program may include the contour shape of the removal area R specified by a shape obtained by adding a tapered shape (a right-angled triangle shape) to a rectangular shape.

[0125] Q_ is the taper amount in the X direction from point B, and R_ is the taper amount in the Z direction from point C.

[0126] At this time, the removal area input unit 12 analyzes the machining program and reads the shape of the removal area R of the workpiece W to be removed by cutting from the contour shape of the removal area in the machining program (rectangular shape and right-angled triangle cone shape). Fig. 13B and Fig.14DWhen the G120 instruction is executed, as described above, the removal area input unit 12 reads the inside of the rectangular shape ABDC as the removal area R based on the position (X, Z) of the point D located at the diagonal of the action start point A or the movement amount (U, W) from the action start point A to the point D. Furthermore, the removal area input unit 12 reads the inside of the right triangle shape B-B'-D as the removal area R based on the address (Q) related to the amount of change in the X-axis direction from point B to point B'. Furthermore, the removal area input unit 12 reads the inside of the right triangle shape C-C'-D as the removal area R based on the address (R) related to the amount of change in the Z-axis direction from point C to point C'.

[0127] In this way, the removal area input unit 12 reads, as the removal area R, an area obtained by merging the interior of the rectangular shape ABDC, the interior of the right triangle shape BB′-D, and the interior of the right triangle shape CC′-D.

[0128] In addition, if Fig. 13C , Fig.13D as well as Fig.14E As shown, the machining program may include the contour shape of the removal area R specified only by a cone shape (right triangle shape).

[0129] At this time, the removal area input unit 12 analyzes the machining program and reads the shape of the removal area R of the workpiece W to be removed by cutting from the contour shape of the removal area in the machining program (the cone shape of a right triangle). Fig. 13C and Fig.14E When the G120 command is shown, the removal area input unit 12 reads the interior of the right triangle BB'-D as the removal area R based on the address (R) related to the change in the Z-axis direction from point B (=point A) to point B'.

[0130] In addition, the machining program includes machining conditions (D1, D2, F1, F2, E, RR, UD) for cutting machining, as described above. The machining condition input unit 14 analyzes the machining program and reads the machining conditions (D1, D2, F1, F2, E, RR, UD) for cutting machining, as described above. And, the action generation unit 16 generates a reciprocating cutting motion based on the removal area read by the removal area input unit 12 and the machining conditions read by the machining condition input unit 14, as described above. Specifically, the action generation unit 16 generates a cutting motion of the tool T in the forward direction and a cutting motion in the return direction relative to the workpiece W, so that the tool T intersects with the uncut portion in the removal area R, and the amount of intersection does not exceed the tool penetration amount in the forward direction and the tool penetration amount in the return direction of the machining conditions.

[0131] As described above, also in the numerical control device of the second embodiment, the same advantages as those of the numerical control device of the first embodiment can be obtained.

[0132] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and various changes and modifications can be made. For example, in the above embodiments, the cutting action in the outward direction and the cutting action in the return direction generated by the action generation unit 16 are straight paths parallel to the rotation axis (Z axis) of the workpiece W, and are paths in opposite directions along the direction of the rotation axis (Z axis) of the workpiece W. However, the present invention is not limited to this.

[0133] For example, the cutting action in the forward direction and the cutting action in the return direction generated by the action generating unit 16 can be the following paths: any straight line path in the plane formed by the rotation axis (Z axis) of the workpiece W and the orthogonal axis (X axis) orthogonal to the rotation axis, paths parallel to each other, and paths in opposite directions along the direction of the rotation axis (Z axis) of the workpiece W.

[0134] Specifically, if Fig.15 As shown, the cutting action in the outward direction and the cutting action in the return direction can be an oblique path with an inclination angle θ (0°<θ<90°) relative to the Z axis.

[0135] at this time,

[0136] If the ZX plane is rotated clockwise by θ and the cutting amounts d1 and d2 are replaced by d1cosθ and d2cosθ, respectively, it can be considered to be the same as the above-mentioned second embodiment.

[0137] The starting point of the cutting path is the point farthest from point A in the X' axis (the coordinate axis after rotating the X axis clockwise by θ). Fig.15 In the example above, it is point D).

[0138] For another example, the cutting action in the forward direction and the cutting action in the return direction can be the following paths: any curved path in the plane formed by the rotation axis (Z axis) of the workpiece W and the orthogonal axis (X axis) orthogonal to the rotation axis, paths parallel to each other, and paths in opposite directions along the direction of the rotation axis (Z axis) of the workpiece W.

[0139] Specifically, if Fig.16 As shown, the cutting action in the outward direction and the cutting action in the return direction can be paths along concentric circles relative to point A.

[0140] at this time,

[0141] Find the intersection points of the arc centered at point A and the outer perimeter of the removal area, and use them as the start / end points of the outward and return paths.

[0142] In addition, in the above-mentioned embodiment, an example is given of a method of reciprocating the tool relative to the workpiece. However, the present invention is not limited to this, and can also be applied to a method of reciprocating the workpiece relative to the tool. That is, the present invention can be applied to a method of reciprocating the tool and the workpiece relative to each other. In this case, the movement of the tool can be replaced by the relative reciprocating movement of the tool and the workpiece.

[0143] In addition, in the above embodiment, the method of rotating the workpiece is exemplified. However, the present invention is not limited to this, and can also be applied to a method of rotating the tool relative to the workpiece. That is, the present invention can be applied to a method of rotating the tool and the workpiece relative to each other. In this case, the rotation of the workpiece can be replaced by the relative rotation of the tool and the workpiece. For example Fig.17 As shown, machining in which a tool is rotated (end mill machining) can be cited. Fig.17 The figure is viewed from the +Z direction (directly above). The cutting action in the outward direction (solid line) is a downward cutting action (-X direction), and the cutting action in the return direction (dashed line) is an upward cutting action (+X direction).

[0144] In addition, in the above-mentioned embodiment ( Figure 2A , Figure 3A , Figure 3B , Figure 4A , Figure 5A ), an example is given in which the machining program includes the contour shape of the removal area R of the workpiece W specified by five straight lines and curves (five moving program blocks N100 to N104). However, the present invention is not limited to this, and the machining program may also include the contour shape of the removal area R of the workpiece W specified by one or more straight lines or curves. For example, Fig.18A and Fig.18B As shown, the machining program may include a contour shape of the removal area R of the workpiece W specified by only one curve (one moving program block N200). Fig.18A In FIG. 1 , the moving block N200 indicates the movement of the cutting feed based on the clockwise circular interpolation to the position Z=10.0 in the Z direction and the arc radius R=10.0. In other words, Fig.18B As shown, the moving program block N200 is specified by an arc A→B→C (point B is the lowest point of the arc).

[0145] Explanation of symbols

[0146] 5 Processing procedures

[0147] 10 Numerical control device

[0148] 12 Remove the area input section

[0149] 14 Processing condition input section

[0150] 16 Action Generation Unit

[0151] 18 Storage

[0152] 20 Machine Tools

[0153] T Tools

[0154] W workpiece.

Claims

1. A numerical control device for a machine tool, which causes a tool and a workpiece to rotate relative to each other and to reciprocate relative to each other, and performs cutting processing on the workpiece by both cutting action in the outward direction and cutting action in the return direction, It is characterized in that The numerical control device of the machine tool has: a removal area input unit that analyzes the cutting process program and reads the shape of the removal area of ​​the workpiece to be removed by the cutting process; a processing condition input unit for reading processing conditions of the cutting process, the processing conditions including at least a cutting amount of the tool in the cutting action in the outward direction and a cutting amount of the tool in the cutting action in the return direction; as well as An action generating unit generates a cutting action in the forward direction and a cutting action in the return direction according to the shape of the removal area and the processing conditions, so that the tool intersects with the uncut portion in the removal area and the amount of intersection does not exceed the amount of cut-in in the forward direction and the amount of cut-in in the return direction in the processing conditions.

2. The numerical control device for a machine tool according to claim 1, It is characterized in that The cutting motion in the outward direction and the cutting motion in the return direction generated by the motion generation unit are the following paths: a straight line path parallel to the rotation axis of the workpiece, or any straight line path or curved path in a plane formed by the rotation axis of the workpiece and an orthogonal axis orthogonal to the rotation axis, parallel paths, and Paths that are in opposite directions along the axis of rotation of the workpiece.

3. The numerical control device for a machine tool according to claim 1, It is characterized in that The program includes: the contour shape of the removal area is specified by a right triangle shape, a rectangle shape, or a shape obtained by adding a cone shape to a rectangle shape, The removal area input unit reads the shape of the removal area from the contour shape of the removal area in the program.

4. The numerical control device for a machine tool according to claim 1, It is characterized in that The program or a subroutine of the program includes: a contour shape of the removal area specified by one or more straight lines or curved lines; The removal area input unit reads the shape of the removal area from the contour shape of the removal area in the program.

5. The numerical control device for a machine tool according to claim 1, It is characterized in that The program also contains the finishing allowance for finishing, The removal area input unit further reads the finishing allowance from the program, and causes the removal area to exclude the finishing allowance or to parallel-shift the removal area by an amount equal to the finishing allowance.

6. The numerical control device for a machine tool according to claim 1, It is characterized in that The processing conditions read by the processing condition input unit and used by the action generation unit further include at least any one of the following: a relative feed speed between the tool and the workpiece in the cutting action in the outward direction, and a relative feed speed between the tool and the workpiece in the cutting action in the return direction; the relative withdrawal of the tool from the workpiece after the cutting action; the relative engagement of the tool and the workpiece during the cutting action; the relative cutting action of the tool and the workpiece during a cutting action; and The cutting direction when the cutting process is finished is set to be either the outward direction or the return direction.

7. The numerical control device for a machine tool according to claim 6, It is characterized in that The path of the cutting-in action or the path of the cutting-out action is: a straight path or a curved path along the periphery of the removal area, or an arbitrary straight path or curved path in a plane formed by the rotation axis of the workpiece and an orthogonal axis orthogonal to the rotation axis.

8. The numerical control device for a machine tool according to claim 1 or 6, It is characterized in that The procedure comprises the processing conditions, The processing condition input unit analyzes the program and reads the processing condition from the program.

9. The numerical control device for a machine tool according to claim 1 or 6, It is characterized in that The numerical control device of the machine tool further comprises: a storage unit which stores the machining conditions in association with the identification information of the tool; The program includes identification information of the tool, The machining condition input unit reads, from the storage unit, machining conditions corresponding to the identification information of the tool read from the program.

10. The numerical control device for a machine tool according to claim 1, It is characterized in that The action generating unit sets a specified position on the periphery of the removal area as the starting position of the cutting action in the forward direction or the starting position of the cutting action in the return direction, and generates a relative approach action of the tool and the workpiece toward the starting position of the cutting action in the forward direction or the starting position of the cutting action in the return direction.

11. The numerical control device for a machine tool according to claim 1, It is characterized in that The cutting action in the outward direction or the cutting action in the return direction generated by the action generation unit includes at least one of the following: relative cutting action of the tool and the workpiece in a direction of the tool toward the uncut portion approaching the removal area; and A relative cutting action of the tool and the workpiece with the tool in a direction away from the uncut portion of the removal area.

12. The numerical control device for a machine tool according to claim 1, It is characterized in that The cutting motion in the outward direction or the cutting motion in the return direction generated by the motion generation unit includes a relative retreat motion or a relative approach motion between the tool and the workpiece in which the tool moves in a direction away from the workpiece.

13. The numerical control device according to claim 1, It is characterized in that The motion generation unit generates a relative retraction motion of the tool and the workpiece in which the tool moves in a direction away from the workpiece when the tool does not intersect an uncut portion in the removal area.

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