JP5453022B2 - CAM system - Google Patents

Description

  The present invention creates software capable of exchanging a tool having an appropriate rotation diameter in accordance with the curvature of a trajectory along which the tool moves in the cutting process associated with the rotation of the cutting tool with respect to the three-dimensional object. The present invention relates to a CAM system and a tool control method based on the software.

  A technique for performing three-dimensional modeling by cutting a rotary tool is well known, and in particular, a three-dimensional modeling object is divided into each layer along a plane in a direction orthogonal to a predetermined direction, and the tool is divided into each layer. A cutting method characterized by sequentially cutting the surface of the steel has been adopted as a modeling method in various fields.

  Therefore, in the case of sequentially cutting the surface of each layer of the three-dimensional modeling object, a cutting trajectory in which the rotation center of the tool moves for each layer is inevitably set in advance by the CAD system, and the trajectory is A plurality of layers are set from the outside to the inside for each layer.

  Each locus inevitably has a curve based on a predetermined curvature, and the curvature reaches various numerical values.

  And for a trajectory having a large curvature region, it is appropriate to select a tool with a smaller rotating diameter because fine machining is required, and this is a common technical knowledge in the industry. It corresponds to.

  However, in the prior art, a general standard necessary for selecting the rotation diameter of the tool is not set corresponding to the curvature of each locus and the locus belonging to a predetermined group.

  Moreover, this situation does not change even when software created by the CAM system is involved in the formation of the trajectory.

  Incidentally, Patent Documents 1 and 2 show a configuration in which software by a CAM system is involved in creating a trajectory in which a tool moves. In Patent Document 1, matters relating to the curvature and tool diameter of a trajectory in which a tool moves. However, the relationship between the two is not specifically discussed, and Patent Document 2 discusses the selection of the shape data of the object to be cut and the type of the tool. It does not provide a general standard for the tool turning diameter to be selected.

JP 2006-235664 A JP 2007-200121 A

  The present invention provides a CAM software that clarifies the criteria necessary for selecting an appropriate tool turning diameter corresponding to the range of the maximum value of curvature that the trajectory of the cutting tool moves. It is an object of the present invention to provide a control system for a tool that is created by the system and based on the arrangement.

In order to solve the above problems, the basic configuration of the present invention is as follows.
(1) In a cutting method associated with the rotation of a tool with respect to a three-dimensional modeling object, the CAM system is linked to a CAD system, and a reference point (Cuting Location: hereinafter referred to as “CL”) on a trajectory along which the tool moves. Abbreviated).) A CAM system capable of creating software for realizing the following steps.
a CL ((x ₁ , y ₁ ),... (x _i , y _i ),... (x _n , y _n ) on a plurality of trajectories from the outside to the inside created by the CAD system ) Is set so that they are arranged at an equal distance from each other on the basis of either the distance on the trajectory between CL and the straight line connecting CL .
b Perform the following calculation for each CL.
Record

但し、

However,

（但し、ｉ＝ｎの場合にｉ＋１の位置は隣接しているｉ＝１の位置であり、ｉ＝１の場合にｉ−１に該当するのは、隣接しているｉ＝ｎの位置である。）
ｃ 外側から内側に至る複数個の軌跡において、前記（ａ）式のうちの最大値を選択する。
ｄ 前記ｃの最大値につき複数段階に区分することによって、複数個の軌跡を内側から外側に掛けて当該複数のグループに区分し、各グループに対応させ、最大値の大きいグループにはより小さな回転径を有する工具を指定する。
（２）前記（１）のＣＡＭシステムによって作成されたソフトウエアに基づいて、各段階に属する軌跡のグループに対応して工具の回転径を選択したうえで、工具による切削を行うことを特徴とすることに基づく工具制御システム、
からなる。

(However, when i = n, the position of i + 1 is an adjacent position of i = 1, and when i = 1, the position corresponding to i-1 is the position of adjacent i = n. is there.)
c In the plurality of trajectories from the outer side to the inner side, the maximum value of the formula (a) is selected.
d By dividing the maximum value of c into a plurality of stages, the plurality of trajectories are divided into a plurality of groups by multiplying them from the inside to the outside, corresponding to each group, and a smaller rotation for a group with a large maximum value Specify a tool with a diameter.
(2) Based on the software created by the CAM system of (1) above, the tool is cut by the tool after selecting the rotation diameter of the tool corresponding to the group of trajectories belonging to each stage. Tool control system based on
Consists of.

  On the basis of the CAM system of (1) and the tool control system of (2), in the present invention, a smaller rotation diameter corresponding to a group having a larger maximum value of curvature in the trajectory constituting the cutting line. By selecting a tool, and conversely, by selecting a larger rotation diameter corresponding to a group having a smaller maximum value, it is possible to achieve both accurate cutting and efficient cutting.

  Furthermore, in the case of each of the above systems, the minimum tool diameter can be calculated and specified corresponding to the maximum value of the curvature, and the three-dimensional modeling can be performed from the group of trajectories partitioned by the maximum value of the curvature. When cutting an object, it is possible to obtain an effect of selecting a minimum necessary tool group.

  In addition, when the trajectory of the tool moves in the course of cutting, the tool may be temporarily cut rapidly due to a so-called “missing” due to a mistake in selecting an appropriate tool diameter. It is possible to prevent damage or a decrease in life.

It is a plan view showing a state where a plurality of trajectories existing from the outside to the inside are divided into groups by dividing the range of the maximum value of curvature according to the equation (a) into a plurality of stages by the step d. Specifically, the case where it divides into 3 groups is shown.

Each group is indicated by the numerical values of (1), (2), and (3), and the groups belonging to the inner side sequentially indicate that the range of the maximum value belongs to a larger group. Dotted lines indicate that other groups exist between the groups (1), (2), and (3).
It is a top view explaining embodiment which adds a new locus according to reduction of cutting width, (a) shows the state of the stage before being added, (b) after being added The state of the stage is shown. The dotted line indicates the same purpose as in FIG.

  First, the basic principle of the basic configuration (1) will be described.

  In step a, as shown in FIG. 1, on the locus 1 created in advance by the CAD / CAM system, in most cases, an arrangement state is set such that CLs are equidistant from each other.

  As the equidistant state, any of a case where the distance on the locus 1 between the CLs is used as a reference and a case where a straight line connecting the CLs is used as a reference can be adopted. The same is true for the purpose of equal distance.

To explain the process b, in the locus 1 generally formed by the function y = f (x), when the radius of curvature is R,
1 / R = f ″ (x) / | 1 + f ′ (x) | ^3/2 (b)
This point corresponds to technical common sense (provided that f ′ (x) = df (x) / dx represents the first derivative by x and f ″ (x) = D ² f (x) / dx ² represents the second derivative with respect to x.

Y _i ′ in the denominator of the equation (a) is an average value of gradients on both sides of the i-th CL of (x _i , y _i ) and is an approximate value of the first derivative, and the numerator of the equation (a) Y _i ″ in (x _i , y _i ) is a further average value of the gradient average value y _i ′ on both sides of (x _i , y _i ). (Average value obtained by dividing by the above), and corresponds to the approximate value of the second derivative.

  As is clear from the equation (a), in step b of the basic configuration (1), the software created by the CAM system for each CL arranged in advance by CAD is an approximate value of curvature. It is attributed to the calculation.

  In step c, the maximum value is selected from the curvatures according to the equation (a) in each trajectory 1 from the inside to the outside, but the ground is that more precise cutting is required in each trajectory 1. Is based on the position where the curvature is maximum and the vicinity thereof.

  In step d, by dividing the maximum value into a plurality of stages, as shown in FIG. 1, the locus 1 is divided into groups of a plurality of regions from the outside to the inside, and each group is dealt with. A turning radius of the tool is set, and a tool having a smaller turning radius is associated with a group having a large maximum value range.

  The basis for the correspondence lies in the common technical knowledge that as the curvature of the correspondence increases, a tool with a smaller rotation diameter can be adapted to precise cutting.

  In addition, the reason why the trajectory 1 can be divided into a plurality of groups according to the region from the outside to the inside corresponding to the plurality of steps of the maximum value of the curvature is that in general cutting, from the outside to the inside, It is based on the fact that the curvature of the locus 1 becomes large and the maximum value also has the same tendency.

  In the tool control system based on the basic configuration of (2), which is based on the CAM system based on the basic configuration of (1), the maximum value of the curvature in step c is used as a reference and is applied to a plurality of regions. By selecting the rotation diameter of the tool corresponding to each divided group, a tool having a smaller rotation diameter is selected for the locus 1 of the group having a large maximum value range, while the maximum value range is small. For the group diameter, by selecting a tool with a larger turning diameter, as pointed out in the effect section, it is possible to achieve both fine cutting in a region with a large curvature and work efficiency in a region with a small curvature. Is possible.

  According to the inventors' experience, when the curvature of the expression (a) does not change extremely in one trajectory 1, the region of the trajectory 1 is divided into three groups in the cutting process from the outside to the inside. In many cases, the tool can be made in time by switching the tool about once, and when the change in the maximum value of the curvature is small, it may be in time in one change.

  Conversely, in the case of cutting with a large curvature change from the inside to the outside, the locus 1 may be divided into groups of 4 to 5 and the tool may be switched about 3 to 4 times.

  In step a, in most cases, the distances between the trajectories 1 that are adjacent to each other from the outside to the inside are set to be approximately equidistant.

  However, in the step d, when a tool having a larger radius of curvature and a smaller rotating diameter in the group belonging to the inner side is selected, the cutting width is also reduced. It cannot be denied that the cutting width may be smaller than the distance between the trajectories 1 that meet each other.

  In order to deal with such inconvenience, as shown in FIGS. 2A and 2B, the cutting width of the specified tool rotation diameter is determined by the distance between adjacent tracks 1 in the group to which the tool belongs. Is shorter, one or more trajectories 1 in which the maximum value of c belongs to the group within the region range of the trajectory 1 in the group are added, and the newly added trajectory 1 and the original trajectory 1 are added. An embodiment in which the arrangement relationship between the trajectories 1 is adjusted so that the mutual distance from the trajectory 1 is equal, and the distance between the trajectories 1 based on the adjustment is equal to or less than the cutting width. To deal with.

  In the above embodiment, the newly added locus 1 can be set to the innermost, outermost, or intermediate region of the group to which it belongs, and the number can be arbitrarily selected. .

  However, as long as each locus 1 is set in an equal distance state in step a, if a new locus 1 is added, the rotation of the tool corresponding to the locus 1 adjacent to each other in each group corresponds. In accordance with the diameter, it is necessary to adjust the distance between adjacent trajectories 1 so as to be equidistant from each other.

  Hereinafter, it demonstrates according to an Example.

  In the first embodiment, the moving speed of the tool is selected corresponding to each group of a plurality of stages, and the maximum value is set between two groups that are installed in adjacent areas having different maximum magnitudes of probabilities. The moving speed of the tool corresponding to the group having a large numerical value of is characterized in that software is added so that the moving speed is smaller or equal to that of the small group.

  That is, in the first embodiment, a group having a larger maximum curvature value can select a smaller moving speed of the tool than a smaller group. It is possible to realize cutting with a smaller moving speed in the trajectory 1 of the group having, thereby contributing to the formation of a precise cutting surface.

  In the second embodiment, the rotation speed of the tool is selected in correspondence with each group of a plurality of stages, and the maximum value between the two groups having different maximum values of curvature and installed in adjacent areas is used. The rotation speed of the tool corresponding to the group having a large numerical value of is characterized in that software is added so that the rotational speed of the tool is larger or equal to that of the small group.

  That is, in the second embodiment, it is possible to select a larger rotational speed in the locus 1 of the group having a large maximum value range, and the amount of cutting caused by selecting a tool having a smaller rotational diameter by the selection. It is possible to cover the decrease and, in turn, the decrease in cutting efficiency.

The present invention can be applied to all methods of manufacturing a three-dimensional structure using a cutting tool.

1 Trajectory 2 Modeled object

Claims (5)

In a cutting method associated with the rotation of a tool with respect to a three-dimensional object, the CAM system is linked to a CAD system, and is referred to as a reference point (Cutting Location: hereinafter referred to as “CL”) on a trajectory along which the tool moves. ), A CAM system capable of creating software that realizes the following processes.
a CL ((x ₁ , y ₁ ),... (x _i , y _i ),... (x _n , y _n ) on a plurality of trajectories from the outside to the inside created by the CAD system ) Is set so that they are arranged at an equal distance from each other on the basis of either the distance on the trajectory between CL and the straight line connecting CL .
b Perform the following calculation for each CL.
Record

However,

(However, when i = n, the position of i + 1 is an adjacent position of i = 1, and when i = 1, the position corresponding to i-1 is the position of adjacent i = n. is there.)
c In the plurality of trajectories from the outer side to the inner side, the maximum value of the formula (a) is selected.
d By dividing the maximum value of c into a plurality of stages, a plurality of trajectories are applied from the outside to the inside to be divided into a plurality of groups, corresponding to each group, and a smaller rotation for a group with a large maximum value. Specify a tool with a diameter. When the cutting width of the rotation diameter of the specified tool is shorter than the distance between adjacent tracks in the group to which the tool belongs, the maximum value of c is set in the group within the range of the track in the group. Based on this adjustment, add one or more tracks that belong to each other and adjust the positional relationship between the tracks so that the distance between the newly added track and the original track is the same distance. The CAM system according to claim 1, wherein a distance between the trajectories is equal to or less than the cutting width.
  A group that selects the moving speed of the tool corresponding to each group of multiple stages, and has a large value of the maximum value between two groups that have different maximum values of curvature and are installed in adjacent areas. The CAM according to any one of claims 1 and 2, wherein software is added so that the moving speed of the tool corresponding to is smaller than or equal to that of a small group. system.   A group in which the rotation speed of the tool is selected corresponding to each group of multiple stages, the maximum value of the curvature is different, and the value of the maximum value is large between the two groups installed in adjacent areas. The CAM according to any one of claims 1 and 2, wherein software is added so that the rotational speed of the tool corresponding to is larger or equal to that of a small group. system.   Based on the software created by the CAM system according to any one of claims 1, 2, 3, and 4, after selecting the rotation diameter of the tool corresponding to the group of trajectories belonging to each group, the tool A tool control system based on cutting.

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