JP5447809B2 - Cutting method capable of forming a sharp angle - Google Patents

Description

  The present invention relates to a cutting method that can form a corner having a sharp angle in a cutting method accompanying rotation of a tool with respect to a three-dimensional object.

  A technique for performing three-dimensional modeling by cutting a rotating tool is well known, and in particular, a three-dimensional modeling object is divided for each layer along a plane perpendicular to a predetermined direction, and the tool is Cutting methods characterized by sequentially cutting the surface of each layer have been adopted as modeling methods in various fields.

  Therefore, in a three-dimensional modeling object, it is often necessary to form a corner portion having a predetermined angle.

However, the tool continuously moves on the machining surface by cutting sequentially, and such a continuous movement is performed even at a portion where the corner is formed. Therefore, even in a corner having a predetermined angle, FIG. As shown in the figure, a protruding state by a curved continuous surface is formed, and forming a corner having a sharp angle based on a protruding state by a non-curved discontinuous surface in a protruding state is a three-dimensional modeling object. The target object is often broken when cutting, and the cutting tool used is also technically difficult due to the occurrence of many breaks caused by overloading due to the rough surface of the three-dimensional object. Was in the situation.
The “sharp angle” in the following description is an angle based on a protruding state by a non-curved discontinuous surface in a protruding state, as shown in FIGS. 4A and 4B, as will be described later. The purpose is not an acute angle of less than 90 degrees (as long as the discontinuous surface is not curved as described above, not only an acute angle but also an obtuse angle of less than 180 °) It is possible to form a sharp angle, and this point is as shown, for example, in FIG.

  Regarding the predetermined angle formation in the three-dimensional modeling field based on the cutting of the tool, for example, in Patent Document 1, when the corner angle formed by the movement of the tool is an acute angle, the tool moves around the corner. A configuration to deal with by correcting the trajectory is disclosed.

  On the other hand, Patent Document 2 discloses a configuration in which the moving speed of a tool is reduced when an acute angle curved inward is formed.

  However, in each of the above-described configurations, it is impossible to form a corner with a sharp angle as long as a tool having a predetermined diameter continuously moves around the corner. It is never easy.

JP-A-6-190683 JP 2001-154718 A

  The present invention realizes a corner portion that forms a sharp angle due to a discontinuous state without being curved by a relatively simple control when the machining surface is formed by cutting a rotating tool. It is an object to provide a configuration to obtain.

In order to solve the above problems, the basic configuration of the present invention is that the tool moves to a specific corner while cutting along one of the machining surfaces, and then leaves the corner to extend the one machining surface. After moving in the specified direction, after moving along a predetermined trajectory without cutting, it returns to the corner position and enters, and the direction to enter intersects with the one processing surface at the corner. A cutting method that accompanies the rotation of the tool relative to the three-dimensional object by reproducing the cut along the other processed surface after the entry , the rotation direction of the tool. A plurality of coordinates that distinguish the trajectory where the center moves are set by numerical values for each one according to the distance between each coordinate, and at the corner where the tool is separated and returned to enter Classification as targets exist and are realized, consisting of cutting process the tool is capable of forming a sharp angle control is performed in the moving direction of the tool each time passes through the position of each coordinate.

  In the basic configuration described above, a tool that is moving while rotating is separated from one processing surface with one processing surface once as a final point, and then in the direction of the other processing surface at the corner using the corner as a starting point. By entering along, the angle at the planned corner is formed between the separation direction and the entry direction, and it is not affected by the continuous movement of the tool, so it forms a corner with a sharp angle It becomes possible to do.

  In addition, the separation and the entry do not require complicated control, and a sharp angle as described above can be formed by relatively simple NC control.

The flowchart of the program in NC controller which controls the movement of a tool in the said basic composition is shown. It is a plane sectional view showing the situation where a tool moves along a locus divided into a plurality of coordinates. It is a side view regarding the situation of multilayer cutting, (a) shows the situation of a multilayer three-dimensional modeling object for which machining control has been performed, and (b) is a state where each layer is not stepwise but continuous The processing method that becomes It is a plane sectional view showing the situation where a tool moves along a predetermined locus, and (a) shows the case where it moves by the locus on the circumference in the middle stage which moves without cutting, (b ) Shows a case of moving along a linear trajectory in an intermediate stage of moving without cutting. The plane sectional view about the composition of an example is shown. It is a plane sectional view showing an embodiment when at least a part of one processing surface and the other processing surface is curving in the state where it was depressed inside, and (a) is only one processing surface inside. (B) has shown the case where both process surfaces are curving inside. It is a plane sectional view which shows the formation condition of the corner angle in a prior art.

  The process of control by the NC controller 3 that realizes the basic configuration is as shown in the flowchart of FIG.

That is, the cutting surface by the tool 1 is formed by moving the rotation center of the tool 1 along a predetermined locus,
Cutting to one machining surface 21 up to the corner 20
↓
Separation from the corner 20 along the extending direction of the one processing surface 21
↓
Without cutting along a predetermined trajectory without cutting,
Controlling the angle of entry into the corner 20 by moving
↓
Crosses one processed surface 21 at the corner 20
Entry into the corner 20 along the direction of the other machining surface 22
↓
The tool 1 is actuated according to the process of cutting the other processed surface 22.

  The trajectory 4 on which the tool 1 moves is set with reference to the rotation center of the tool 1 as shown in FIG. 2, and after setting the coordinates 41 based on each section along the trajectory 4, in particular the corner 20. In the movement without cutting after the removal is performed after judging from the corner 20 due to the extension direction of one of the machining surfaces 21 depending on whether or not the coordinates corresponding to the position have been reached. Is controlled along the direction of the other machining surface 22 that intersects one machining surface 21 at the corner 20 by controlling the angular direction as described above while moving the position on each coordinate on the locus 4. Thus, it is preferable to enter the corner 20.

  The coordinate position is usually set as a two-dimensional or three-dimensional numerical parameter to which the tool 1 is moving.

  As described above, when the coordinate position is used as an absolute reference, the moving direction of the tool 1 is naturally set according to the relationship between the current position coordinate position and the next position coordinate position.

However, when the moving direction at the coordinate position in a specific stage is set as a parameter, the coordinate position in the next stage can be specified by setting a parameter with a single numerical value in accordance with the distance in the direction.

Paying attention to such points, while setting a plurality of coordinates 41 that divide the trajectory 4 along which the rotation center of the tool 1 moves by each numerical value corresponding to the distance between the coordinates , the tool 1 is detached, In addition, in the corner 20 that returns and enters, a section in which specific coordinates exist is realized, and control of the moving direction of the tool 1 is adopted as a basic configuration every time the tool 1 passes the position of each coordinate. Yes.

In the basic configuration , it is indispensable for the NC controller 3 to set the moving direction of the tool 1 for each coordinate position, but whether or not the tool 1 has reached the position corresponding to the corner 20 in the flowchart of FIG. This determination is excellent in that a quick determination can be made that a determination is made based on a parameter based on a single numerical value in a predetermined trajectory.

The three-dimensional modeling object 2 on which the cutting method of the present invention is performed is not particularly limited.
However, as shown in FIG. 3 (a) in particular, the present invention is such that the three-dimensional modeling object 2 is divided for each layer along a plane in a direction orthogonal to a predetermined direction, and the tool 1 is formed of each layer. In the embodiment characterized by sequentially cutting the surface, the trajectory 4 along which the tool 1 moves can be set two-dimensionally along the plane direction, and therefore can be suitably applied.

  In FIG. 3A, it seems that a step is formed at first glance, but the step is not necessarily formed in the multilayer cutting.

  That is, as shown in FIG. 3 (b), the cutting surface of the tool 1 can be formed at an angle inclined with respect to a predetermined reference direction to form a state in which the cutting surface is successively continuous for each layer. In the embodiment, it is possible to realize the three-dimensional modeling object 2 with a continuous inclined surface instead of an inclined surface with a step.

  As shown in the flowchart of FIG. 1 and the flat side view of FIG. 2, after the tool 1 leaves the corner 20 along the extending direction of one processing surface 21, the other processing surface 22 intersects at the corner 20. It is indispensable to sequentially control the movement direction of the tool 1 so as to enter the corner 20 along a certain direction, in other words, to move along a trajectory that enables such control. .

For example, as shown in FIG. 4A, the trajectory in which such control is most easily realized is a straight line in the initial stage and the final stage in the process in which the tool 1 leaves the corner 20 and returns to the corner 20 again. The tool 1 as shown in FIG. 4 (b) is further extended in an embodiment characterized in that the tool 1 moves along a trajectory of the shape and moves along the trajectory of the circumference in an intermediate stage. In the process of moving and returning to the position of the corner 20 again, moving along a linear trajectory in the initial stage and the final stage, and also in a linear direction in the intermediate stage In the embodiment, the direction of the linear trajectory entering the corner 20 of the final stage can be easily set by appropriately selecting the length of the arc trajectory or the linear trajectory at the intermediate stage. That is very convenient in terms.
As is clear from FIGS. 4A and 4B, the trajectory 4 along which the tool 1 moves is set with reference to the rotation center, and the tool 1 has a corner along the extending direction of the one machining surface 21. The direction of detaching from 20 and the direction of entering the corner 20 along the direction in which the other machining surface 22 intersects are also set based on the locus along the rotation center. Is always at a position away from the center of rotation by the distance of the radius of rotation, by setting each of the above directions in accordance with a trajectory based on the center of rotation, in the corner 20 of the present invention It turns out that the formation of a sharp angle is sufficiently feasible.

  According to the present invention, as shown in FIGS. 6A and 6B, one of the machining surfaces 21 and the other machining surface 22 located on both sides of the corner 20 (in the case of FIG. 6A). ), Or both (in the case of FIG. 6 (b)), it is also possible to form a sharp angle with a processed surface that is curved in a state of being recessed inward.

  In the present invention, the position of the corner 20 that forms a sharp angle is set, and the tool 1 leaves the corner 20 and moves without cutting, and then returns to the position of the corner 20 and enters again. It is essential to set the trajectory.

  For such setting of the position of the corner 20, software for selecting the position of the corner 20 is effectively used on the basis of the following formula (a) created by the CAM system linked with the CAD system. be able to.

In a cutting trajectory in which the rotation center of the tool 1 that has been created in advance is moved by the CAD / CAM system, the position based on the orthogonal coordinates of an array point (cutting location, hereinafter abbreviated as “CL”) serving as a cutting reference. For (x ₁ , y ₁ ),... (X _i , y _i ),... (X _n , y _n ), curvature 1 / R _i (where R _i is at point _i ) according to the following approximate expression: represents the radius of curvature.) or calculated in advance an expression) multiplied by a predetermined coefficient the curvature 1 / R _i of the proportional (in 1 / R _i, when the curvature is predetermined value or more, sharp angles By a CAM that causes the CAD system to create a trajectory from the time of leaving the corner 20 until returning to the position of the corner 20 based on the selection. Software that was created Te.
Record

但し、

However,

であって、かつ

And

を条件とする。
尚、上記不等式において、ａ、ｂはそれぞれ切削工具１の移動による軌跡４の中心に係るｘ軸方向及びｙ軸方向の座標（ａ、ｂ）に対応する数値を表しており、前記各式において、ｉ＝ｎの場合のｉ＋１に該当する座標の指標は１であり、ｉ＝１の場合のｉ−１に該当する座標の指標はｎである。

As a condition.
In the above inequality, a and b represent numerical values corresponding to the coordinates (a and b) in the x-axis direction and the y-axis direction, respectively, relating to the center of the locus 4 by the movement of the cutting tool 1. , The coordinate index corresponding to i + 1 when i = n is 1, and the coordinate index corresponding to i-1 when i = 1 is n.

In general, the curvature 1 / R when the function y = f (x) is
1 / R = | f ″ (x) / {1 + f ′ (x)} ^3/2 | (e)
(Where f ′ (x) represents the first derivative with x, and f ″ (x) represents the second derivative with x). This corresponds to the approximate expression indicating the curvature of e).

Incidentally, the expression (b) constituting the denominator in the expression (a) shows an average expression of the gradient at the i-th coordinate position, and corresponds to an approximate expression of f ′ (x) which is a primary differential expression. The equation (c) constituting the numerator of the equation (a) is an average value of the gradient based on the equation (b) at the i-th coordinate position, which is an adjacent unit length in the x-axis direction. It is an average value obtained by dividing by (x _{i + 1} -x _i ) and (x _i -x _i-1 ), and corresponds to an approximate expression of f ″ (x) which is a secondary differential expression.

That is, equation (a) is an approximate expression of curvature at the i-th coordinate, and equation (a) indicates that the greater the numerical value, the more severe the curve, but the corner 20 position that forms a sharp angle. Shows a numerical value that is an order of magnitude larger than the radius of curvature of other smoothly continuous coordinate positions. Therefore, the position to be the corner 20 is specified by setting the expression (a) to a predetermined numerical value or higher. can do.
Note that the condition of the inequality of equation (d) is that if the i-th coordinate corresponds to the sharp corner 20, the i-th coordinate position is adjacent to the i-1th coordinate and the i + 1-th coordinate. When the rotation center is used as a reference with respect to the coordinates, the distance from the rotation center is the rotation of each adjacent coordinate position when the distance from the rotation center is used as a reference. This is based on the fact that the distance is larger than the distance from the center coordinate position (a, b) .

And not only the curvature 1 / R _i according to the equation (a) but also the proportional expression of the curvature 1 / R _i , that is, c / R _i (where c is a proportional coefficient) includes the proportional equation. In this case, it is based on the fact that it is possible to specify the position to be the corner 20 as in the case of the equation (a).

  After specifying and selecting such a corner 20 position by software created by the CAM, a trajectory until the tool 1 is detached from the corner 20 by the CAD / CAM system and enters the corner 20 again. The software corresponding to the trajectory can be naturally created by the CAM.

  In the present invention, it is naturally possible to control the movement of the tool 1 based on software created by a CAM system linked to the CAD system.

  The position of the corner 20 is not determined by the exact curvature as in the expression (a), but the position of the corner 20 is based on the following expression (f) by focusing on the inequality of the expression (d). This can also be realized by software for selecting.

A position (x ₁ , y ₁ ) based on Cartesian coordinates of CL, which is an array point serving as a cutting reference, in a cutting locus 4 in which the rotation center of the tool 1 is moved in advance by the CAD / CAM system. _{·· (x i, y i)} , ··· (x n, y n) for, calculated in advance (equation multiplied by a predetermined coefficient [Delta] L _i) below [Delta] L _i or proportional expression of the [Delta] L _i, When the ΔL _i or the proportional expression of the ΔL _i is greater than or equal to a predetermined numerical value, the corner 20 having a sharp angle is selected and the corner 20 is separated from the corner 20 based on the selection. Software created by the CAM that causes the CAD system to create a trajectory up to the point of entry to the point of entry.
Record

尚、上記ΔＬ _ｉ において、ａ、ｂはそれぞれ切削工具１の移動による軌跡４の中心に係るｘ軸方向及びｙ軸方向の座標、即ち（ａ、ｂ）に対応する数値を表しており、前記各式において、ｉ＝ｎの場合のｉ＋１に該当する座標の指標は１であり、ｉ＝１の場合のｉ−１に該当する座標の指標はｎである。

In the above ΔL _i , a and b represent the numerical values corresponding to the coordinates in the x-axis direction and the y-axis direction with respect to the center of the locus 4 by the movement of the cutting tool 1, that is, (a, b), In each equation, the coordinate index corresponding to i + 1 when i = n is 1, and the coordinate index corresponding to i-1 when i = 1 is n.

In the equation (f), when the center position (a, b) of the trajectory 4 along which the tool 1 moves is used as a reference, the coordinate position (x _i , y _i ) and the coordinate positions (x _i−1 , y _i ) on both sides are used. ₋₁ ) and (x _{i + 1} , y _{i + 1} ), the sum of the distance differences, ie

を算定した場合、前記差の総和は、先鋭な角度を呈するコーナー２０位置の場合には、なだらかに接続している座標位置の場合に比し、極端に大きな値を呈することに立脚している。
尚（ｆ）式自体ではなく、（ｆ）式によるΔＬｉだけでなく、ΔＬｉの比例式、即ちｃ・ΔＬｉ（尚、ｃは定数）を包摂しているのは、当該比例式の場合においても（ｆ）式と同様にコーナー２０となる位置を特定することが可能であることに立脚している。

Is calculated, the sum of the differences is based on an extremely large value in the case of the corner 20 position exhibiting a sharp angle as compared with the case of the smoothly connected coordinate position. .
Note that not only the equation (f) itself but also ΔLi according to the equation (f), the proportional equation of ΔLi, that is, c · ΔLi (where c is a constant) is included even in the case of the proportional equation. It is based on the fact that it is possible to specify the position to be the corner 20 as in the equation (f).

  Then, a trajectory that leaves the corner 20 and then returns to the corner 20 to enter again can be created by the CAD / CAM system, and software corresponding to the trajectory can be created by the CAM. There is no difference from the case of the embodiment based on the formula (a).

  Hereinafter, description will be made with reference to examples.

  In the first embodiment, as shown in FIG. 5, when the surface of the three-dimensional object 2 is cut a plurality of times, the tool 1 is detached from the corner 20 in the processing stage from the first time to the middle number of times. Without moving the tool 1 continuously from the one machining surface 21 along the other machining surface 22, and after passing through the above-mentioned number of machining steps, the tool 1 leaves the corner 20 and returns to the corner 20 to enter again. It is characterized by moving.

  Surface processing at a predetermined position by the tool 1 is not necessarily performed all at once, while setting a final modeling surface, setting a plurality of rotation center trajectories, and performing cutting corresponding to each trajectory Sequentially machined surfaces are formed, especially in the case of multi-layer cutting as shown in FIG. 3, in most cases the final result is based on such a plurality of trajectories (actually at least tens of trajectories). A typical processed surface is formed.

  In such a case, the sharp angle at the corner 20 may be formed at the final stage, and at the previous stage, formation of a sharp angle is never required at a position outside the corner 20.

  That is, after the movement of the tool 1 along a plurality of trajectories, in the middle stage, as in the case of the prior art, even if a continuous curved angle is formed, there is no problem. As in the configuration, if the corner 20 is detached and entered, work efficiency is inevitably lowered.

In the case of the first embodiment, the work efficiency as a whole can be improved by adopting the prior art until reaching the trajectory in the middle stage.
However, it is indispensable to set the degree of cutting and the number of trajectories after the intermediate stage so that a sharp angle can be formed by cutting along the trajectory after the intermediate stage from the trajectory after the intermediate stage. Needless to point out again.

In the second embodiment, assuming that the position of the corner 20 is selected and set by the software created by the CAM system, the coordinate position of the corner 20 is set to (x _i , y _i ), and the coordinate position of CL positioned f times before the coordinate position of the corner 20 in the trajectory before the tool 1 leaves the corner 20 (where f is one or more) ) Is (x _i−f , y _i−f ), and the coordinate position of CL positioned k pieces after the corner 20 in the locus after the tool 1 leaves the corner 20 (where k is s) a (x i _{+ k,} when the y i _{+ k),} for the tool 1 from the corner 20 to maintain the same direction immediately before and immediately after leaving, to hold each proportional formula While setting the respective coordinate positions in advance in the CAM system to, when the tool 1 is rush back again to the position of the corner 20, the coordinates of the corner 20 (x _{j, y j)} upon setting (except , (X _j , y _j ) are at the same position as (x _i , y _i ).) In the trajectory before entering the corner 20, m coordinates before the coordinate position of the corner 20 The coordinate position of the CL at the position (where m is one or more) is (x _{j− n} , y _{j− n} ), and in the locus after entering the corner 20, p points after the corner 20. When the coordinate position of the CL that is located (where p is one or more) is (x _{j + p} , y _{j + p} ), the same direction is maintained immediately before and after the tool 1 enters the corner 20 again. To do the following It is characterized in that software that satisfies each proportional expression is created by CAM.
Record

By the establishment of the above proportional expression, the coordinate position of (x _i , y _i ) and the coordinate position of (x _j , y _j ) that become the corner 20 (both represent the same position, but are different for convenience of explanation) On the other hand, it is ensured that the direction immediately before and after the tool 1 enters is the same, and a sharp angle can be reliably formed.
In the case where k, f, m, and n are each a plurality of numerical values, the same direction according to the above general formula can be obtained even at a coordinate position for a numerical value smaller than such a numerical value, that is, a coordinate position closer to the position of the corner 20. Will be guaranteed.

  The present invention can be used in all fields of surface processing based on cutting using rotation of a tool.

DESCRIPTION OF SYMBOLS 1 Tool 2 Three-dimensional modeling target object 20 Corner 21 One processing surface 22 The other processing surface 23 Each layer in a three-dimensional modeling target 3 NC controller 4 The locus | trajectory 41 in which a tool moves 41 The coordinate which classifies a locus | trajectory

Claims (10)

After the tool moves to a specific corner while cutting along one of the machining surfaces, the tool moves away from the corner and moves in the direction in which the one machining surface is extended. After moving along a trajectory and returning to the corner position, the direction of entry is the intersecting direction of the other machining surface intersecting the one machining surface at the corner, and the entry Thereafter , a cutting method that accompanies the rotation of the tool with respect to the three-dimensional object by reproducing the cutting along the other processing surface, and a plurality of coordinates that classify the trajectory in which the rotation center of the tool moves are each coordinate. Set according to the numerical value of each piece according to the distance between them, and at the corner where the tool detaches and returns and enters, a division where specific coordinates exist is realized. There cutting method capable of forming a sharp angle control is performed in the moving direction of the tool each time passes through the position of each coordinate.   The sharp angle according to claim 1, wherein the three-dimensional modeling object is divided for each layer along a plane in a direction orthogonal to a predetermined direction, and the tool sequentially cuts the surface of each layer. Cutting method that can be formed. 3. The sharp angle is formed according to claim 2 , wherein the cutting surface can form a continuous state for each layer by cutting the tool at an angle inclined with respect to a predetermined reference direction. Cutting method to get.   In the process where the tool leaves the corner and returns to the corner position again, the tool moves along a linear trajectory in the initial stage and the final stage, and moves along a circumferential trajectory in the intermediate stage. The cutting method which can form the acute angle as described in any one of Claims 1, 2, 3 characterized by the above-mentioned.   In the process in which the tool moves in the extension direction and returns to the corner position again, the tool moves along a linear trajectory in the initial stage and the final stage, and also in a linear direction in the intermediate stage. The cutting method which can form the acute angle as described in any one of Claims 1, 2, 3, and 4 characterized by the above-mentioned.   The at least one part of one process surface and the other process surface which are located in the both sides of a corner is curving in the state dented inside, The 1, 2, 3, 4 characterized by the above-mentioned. A cutting method capable of forming the sharp angle according to any one of 5.   When cutting the surface of a 3D modeling object multiple times, in the machining stage from the first to the middle number of times, the tool continues from one machining surface along the other machining surface without leaving the corner. And after passing through the intermediate number of machining steps, the tool moves away from the corner and moves back into the corner and enters the corner again. The cutting method which can form the acute angle as described in any one of Claims 6. In a cutting trajectory in which the center of rotation of a tool that has been created in advance is moved by a CAD / CAM system, a position (Cutting Location, hereinafter abbreviated as “CL”) as a reference for cutting is a position by orthogonal coordinates ( For x ₁ , y ₁ ),... (x _i , y _i ),... (x _n , y _n ), curvature 1 / R _i according to the following approximate expression (where R _i is the curvature at point _i) represents the radius.) or the curvature 1 / R _i proportional equation (equation multiplied by a predetermined coefficient 1 / R _i) calculated in advance, when the curvature is predetermined value or more, a sharp angles C is a software program that selects and creates a trajectory from the departure from the corner to the return to the corner position based on the selection to the CAD system. The sharp tool according to any one of claims 1, 2, 3, 4, 5, 6, and 7, wherein the tool movement is controlled based on the software. A cutting method capable of forming an angle.
Record

However,

And

As a condition.
In the above inequality, a and b represent numerical values corresponding to the coordinates (a and b) in the x-axis direction and the y-axis direction related to the center of the trajectory due to the movement of the cutting tool, respectively, The index of the coordinate corresponding to i + 1 when i = n is 1, and the index of the coordinate corresponding to i-1 when i = 1 is n. A position (x ₁ , y ₁ ) based on the orthogonal coordinates of CL, which is an array point serving as a cutting reference, in a cutting trajectory in which the rotation center of a tool that has been created in advance is moved by a CAD / CAM system,... _{(x i, y i),} ··· (x n, y n) for, calculated in advance (equation multiplied by a predetermined coefficient [Delta] L _i) proportional to the following [Delta] L _i or the [Delta] L _i, the [Delta] L _{When i} or the proportional expression of ΔL _i is greater than or equal to a predetermined value, the corner is selected to be a corner having a sharp angle, and after leaving the corner based on the selection, the corner is returned to the corner position. The software for causing the CAD system to create a trajectory up to the point of entry is created by the CAM, and the tool movement is controlled based on the software. Cutting method capable of forming a sharp angle as claimed in any one of 3,4,5,6,7.
Record

In the above ΔL _i , a and b represent numerical values corresponding to the coordinates (a and b) in the x-axis direction and the y-axis direction related to the center of the trajectory due to the movement of the cutting tool, respectively, , The coordinate index corresponding to i + 1 when i = n is 1, and the coordinate index corresponding to i-1 when i = 1 is n. The coordinate position of the corner is set to (x _i , y _i ), and the coordinate position of CL positioned f times before the coordinate position of the corner in the trajectory before the tool leaves the corner (where f Is a singular or plural number) (x _i−f , y _i−f ), and in the trajectory after the tool leaves the corner, the coordinate position of the CL positioned k times after the corner (where k Is a singular or plural number) (x _{i + k} , y _{i + k} ), in order to maintain the same direction immediately before and after the tool leaves the corner, the following CAM is established so that the following proportional expressions are satisfied. While each coordinate position is set in the system in advance, when the tool returns to the corner position again and enters the corner position, the coordinates of the corner are set as (x _j , y _j ) (however, (x _j , y _j ) (X _i , y _i ) is the same position as above)) In the trajectory before entering the corner, the coordinate position of CL at the position m ahead of the coordinate position of the corner (where m is Singular or plural) is (x _j−m , y _j−m ), and the coordinate position of CL that is located after the corner by p in the locus after entering the corner (where p is a single number) Or (multiple) is set to (x _{j + n} , y _{j + n} ), and software that satisfies the following proportional expressions to maintain the same direction immediately before and after the tool enters the corner again The cutting method according to any one of claims 8 and 9 , wherein a sharp angle can be formed.
Record

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