JP5733520B2 - Tool passing area modeling method - Google Patents

Description

  In the present invention, in machining by numerical control (NC), particularly NC milling, an area through which a tool passes (tool passing area) when moving the tool along a predetermined tool path is modeled. The present invention relates to a tool passing area modeling method.

In NC milling, when designing a jig to be used for a clamp placed on a workpiece to be machined using a 3D CAD (Computer Aided Design) device, etc., a tool passage area (tool) 3D shape trajectory) needs to be modeled. This is to design a jig that does not interfere with the tool passage area, that is, to prevent the jig from contacting or colliding with a machining tool.
Therefore, modeling of the tool passing area has been conventionally performed. For example, a CAD device having a method (Patent Document 1) of sweeping a surface figure to form a three-dimensional model as one of its functions is used, and an operator of the CAD device can determine a predetermined tool path and tool. Modeling was performed manually using three-dimensional shapes (data).

JP-A-8-339455

As described above, conventionally, modeling of the tool passing area has been performed manually using a CAD apparatus, so that many man-hours and lead times are required.
In particular, the shape of the tool passage region cannot be defined depending on the geometric relationship between the tool shape and the tool path, in particular, the magnitude relationship between the tool diameter and the arc diameter at the arc portion of the tool path. For this reason, although many parts of the tool passage area can be created, the above undefinable part becomes a bottleneck, and it takes a lot of time and labor to create the entire tool passage area (tool passage area modeling). There were many.

  The present invention has been made in view of the above circumstances, a tool that can avoid the indefinable state of the shape of the tool passage region as much as possible, and can shorten the creation time of the tool passage region including the arc portion. It is an object to provide a passing area modeling method.

The above-described problem is solved by making the tool passing area modeling method have the following configurations.
As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the present invention, and the technical features described in this specification and combinations thereof should not be construed as being limited to those described in the following sections. . In addition, when a plurality of items are described in one section, it is not always necessary to employ the plurality of items together, and it is also possible to take out only a part of the items and employ them.

Of following sections (1) term corresponds to claim 1. The item ( 2 ) is not a claimed invention.

(1) In a tool passage region modeling method for modeling a region through which a tool passes when a tool is moved along a predetermined tool route in machining a workpiece by numerical control, the tool path is defined as a straight portion and an arc portion. For the straight part, a tool cross-sectional shape is swept along the tool path to create a tool passage region, and for the arc part, the tool part is divided into an inner side and an outer side of the tool path, and the tool For the outside of the path, the tool cross-sectional shape is swept along the tool path to create a tool passing area, and for the inside of the tool path, the radius of the tool path is the radius of the arc portion of the tool path. The tool is divided into a larger part and a smaller part, and the tool shape radius is equal to or smaller than the radius of the arc part of the tool path. After the tool cross-sectional shape is swept along the path to create the tool passing area, the tool passing areas are connected to create the tool passing area of the arc part, A tool passing area modeling method, wherein a tool passing area model is created by connecting tool passing areas of arc portions in accordance with a movement order of the tool on the tool path.
An example of machining the workpiece by the above numerical control is NC milling, in which a cutting blade is provided on the lower end surface of the tool and the surface is cut.
Sweep is one of three-dimensional graphic modeling techniques, and refers to a method of moving a figure drawn on a plane along a certain trajectory into a three-dimensional shape. Moving in a straight line gives the same result as extrusion. Twist and rotation can be added by defining the trajectory with parameters.
The tool shape is directly used as the tool passage region (the trajectory of the tool three-dimensional shape) for the start end and the end of the tool path.
The portion where the radius of the tool shape is larger than the radius of the arc portion of the tool path is outside the scope of the invention described in (1), and the tool passage area of this portion is not created.
(2) (1) with a tool passage region model created by the tool passing region modeling methods described, CAD apparatus characterized by designing a member that includes a jig placed on the workpiece.
According to the invention described in the item ( 2 ), it is possible to easily design a member such as a jig that does not interfere with the tool passage region (contact or collision with the tool).

In the invention described in item (1), in the tool passing region modeling method, the tool path is divided into a straight portion and an arc portion. And for arc portion, divided into an inner and outer tool path for the outer arcuate portion of the tool path to create a tool passage region by sweeping the tool cross-section along the tool path, the inside of the tool path Is divided into a portion of the tool shape whose radius is greater than or equal to the radius of the arc portion of the tool path. For the part where the radius of the tool shape is the same as or smaller than the radius of the arc part of the tool path, create a tool passing area by sweeping the tool cross-sectional shape along the tool path, and then connect the tool passing areas. The tool passage area of the arc part was created.
Therefore, as long as there is no portion where the radius of the tool shape is larger than the radius of the arc part of the tool path, it is possible to avoid a state where the shape of the tool passing area in the arc part cannot be defined, and the tool passing area model including the arc part The creation time of can be greatly reduced.
Since the invention described in item ( 2 ) is not the present invention (the invention described in the claims), the effect is described in the section for solving the above-mentioned problems.

It is a perspective view which shows an example of the tool path | route where modeling of a tool passage area is performed with a workpiece | work. It is a schematic explanatory drawing at the time of the modeling start of the tool passage area | region in the tool path containing a circular arc part. It is a flowchart for demonstrating the tool passage area | region modeling method which concerns on one Embodiment of this invention. It is explanatory drawing of each part of the tool passage area produced by the tool passage area modeling method shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.
FIG. 1 is a perspective view showing an example of a tool path including a circular arc portion where modeling of a tool passage area is performed in NC milling, together with a workpiece.
In this figure, 1 is a workpiece, 2 is a milling tool, 3 is a tool path, and 4 is a member such as a jig.

  The milling tool 2 (hereinafter simply referred to as a tool) has a cutting blade 2a at the lower end surface, and moves on the workpiece 1 while rotating around the axis to cut a predetermined surface. In the illustrated example, cutting of a predetermined workpiece on the workpiece 1, specifically, the tip surfaces 1 b of a plurality of predetermined workpieces 1 a protruding from the side surface of the workpiece is sequentially performed.

  The tool path 3 refers to a path along which the tool 2 moves during the cutting process, specifically, a path (data) on a two-dimensional plane of the tool center position when the tool 2 moves. In the example of illustration, it is set on the side surface of the workpiece 1 which is a machining surface. Cutting on a desired two-dimensional plane in the three-dimensional space is also possible by moving the same two-dimensional plane in the axial direction perpendicular to the two-dimensional plane and setting a new tool path 3.

When the tool 2 moves along the tool path 3, a tool passing area (trajectory of the tool three-dimensional shape) of the tool 2 is drawn. By modeling the drawn tool passing area, it is possible to design a member 4 such as a jig that interferes with the tool passing area, that is, does not contact or collide with the tool 2.
Examples of the member 4 such as a jig include a jig used for a clamp or the like disposed on the workpiece 1. The design of the member 4 such as a jig refers to the design of various elements that cause interference with the tool passage region, such as the outer shape, size, or arrangement position of the member 4.
The tool path 3 normally includes a straight line portion 3a and a circular arc portion 3b as shown in a simplified manner in FIG.

Next, a modeling procedure of the tool passage region (tool three-dimensional shape trajectory) according to the present embodiment will be described with reference to FIGS.
Here, as shown in FIGS. 1 and 2, the tool 2 is moved along the tool path 3 to cut the workpiece 1, specifically, the front end surfaces 1 b of the plurality of workpieces 1 a on the workpiece 1. The case will be described. This embodiment is executed by, for example, a three-dimensional graphic processing device including a three-dimensional CAD device.

3, first, in step 301, the tool path 3 is divided into a straight line portion 3a and a circular arc portion 3b (see FIG. 2).
The work 1, the tool path 3 on the work 1 and the tool 2 (see FIGS. 1 and 2) are determined in advance and stored in, for example, a three-dimensional CAD apparatus. In step 301, the tool path 3 memorize | stored in the three-dimensional CAD apparatus is read, and it divides | segments into the linear part 3a and the circular arc part 3b.
In the present embodiment, the workpiece 1 and the tool 2 are set by three-dimensional shape data, and the tool path 3 is set by data on a two-dimensional plane (workpiece side surface) in the three-dimensional space in which the three-dimensional shape data is set. Each data is represented by a common origin.

In step 302, the tool cross-sectional shape 2b (see FIG. 4A) is swept along the tool path 3 with respect to the straight line part 3a out of the straight line part 3a and the circular arc part 3b of the tool path 3, and the straight line part 3a The tool passage area 41 (41a, 41b) [see FIG. 4B] is created.
Here, “sweep” is one of three-dimensional graphic modeling techniques, and refers to a technique of moving a figure drawn on a plane along a trajectory into a three-dimensional shape. Specifically, it refers to a method of creating a tool passage region (tool three-dimensional shape trajectory) by moving the tool cross-sectional shape 2b along the tool path 3.

  The arc portion 3b of the tool path 3 is divided into an outer side 3c and an inner side 3d (see FIGS. 2 and 4A), and step 303 is executed for the outer side 3c. That is, in step 303, the tool cross-sectional shape 2b is swept along the tool path 3 to create a tool passing region 42 [see FIG. 4C] on the outer side 3c of the arc portion 3b.

  Regarding the inner side 3d of the arc portion 3b of the tool path 3, in step 304, the radius r (r1, r2, r3) of the shape of the tool 2 (tool shape, specifically, the tool three-dimensional shape) is the tool path 3 Is divided into a portion 3e that becomes larger (r> R portion) 3e and a portion 3f that is the same or smaller (r ≦ R portion) with respect to the radius R of the arc portion 3b of FIG. (See FIG. 4 (a)).

In step 305, for the inner side 3d of the arc portion 3b of the tool path 3, the portion of the shape of the tool 2 whose radius r is the same as or smaller than the radius R of the arc portion 3b of the tool path 3 (r ≦ R With respect to the portion 3f, the tool cross-sectional shape 2b is swept along the tool path 3 to create a tool passage region 43 (see FIG. 4D) in the portion 3f.
Regarding the inner side 3d of the arc portion 3b of the tool path 3, a portion (r> R portion) 3e in which the radius r of the shape of the tool 2 is larger than the radius R of the arc portion 3b of the tool path 3 is as follows. In this embodiment, it is not necessary to automatically create the tool passage area for that part (because it is completely included in the tool passage area 41 when connected in the next step 307), and the tool passage area for that part is not created (step 306). .

In step 307, the tool passing regions 41 to 43 created as described above are connected in accordance with the movement order of the tool 2 on the tool path 3. That is, the tool passing area 41 (41a, 41b) of the straight line part 3a created in step 302 (see FIG. 4B) and the tool passing area in the outer side 3c of the arc part 3b of the tool path 3 created in step 303. 42 (see FIG. 4C), the tool passing region 43 [see FIG. 4D] in the inner side 3d of the same arcuate portion 3b created in step 305 is matched with the movement order of the tool 2 on the tool path 3. Connect.
As for the start end and the end of the tool path 3, the tool shape as it is, but in practice the portion overlapping with the tool passage region 41 (41a, 41b) portion of the straight portion 3a is excluded, so the half shape of the tool 2 is A tool passing area model (a series of tool passing areas) 40 is connected to the tool passing areas 41 (41a, 41b) adjacent to the tool passing areas 44 and 45 when the tool passing areas 41 to 43 are connected. Complete.

The effects of the present embodiment described above will be described with reference to FIGS. 2 and 4. According to the present embodiment, the tool path 3 is divided into a straight portion 3a and an arc portion 3b in the tool passing area modeling method. The arc portion 3b is divided into an inner side 3d and an outer side 3c of the tool path 3, and each tool passing area 42 is created by sweeping the tool cross-sectional shape 2b along the tool path 3 to create the tool passing area 42. , 43 are connected to create a tool passage region (42 + 43) of the arc portion 3b.
In particular, for the outer side 3c of the arc portion 3b of the tool path 3, the tool cross-sectional shape 2b is swept along the tool path 3 to create a tool passing region 42, and for the inner side 3d of the tool path 3, The portion 3e is divided into a portion 3e whose radius r is greater than or equal to the radius R of the circular arc portion 3b of the tool path 3 and a portion 3f. For a portion 3f in which the radius r of the tool shape is the same as or smaller than the radius R of the arc portion 3b of the tool path 3, the tool cross-sectional shape 2b is swept along the tool path 3 to create the tool passage area 43. The tool passing regions 42 and 43 are connected to create the tool passing region 42 + 43 of the arc portion 3b.
Therefore, unless the portion 3e in which the radius r of the tool shape is larger than the radius R of the arc portion 3b of the tool path 3 is generated, it is possible to avoid the state in which the shape of the tool passage area in the arc portion 3b cannot be defined. The creation time of the tool passing area model 40 including 3b can be greatly shortened.

1: Workpiece, 2: Milling tool, 3: Tool path, 4: Member such as jig, 3a: Straight part of tool path, 3b: Arc part of tool path, 3c: Outside arc part, 3d: Arc part Inside, 3e: a part where the radius of the tool shape is larger than the radius of the arc part of the tool path, 3f: a part where the radius of the tool shape is the same as or smaller than the radius of the arc part of the tool path, 41 to 45: tool passing region (tool (3D shape trajectory), 40: tool passage area model.

Claims (1)

In a tool passage region modeling method for modeling a region through which a tool passes when moving a tool along a predetermined tool path in machining a workpiece by numerical control,
Dividing the tool path into a straight line part and an arc part;
For the straight part,
Sweeping the tool cross-sectional shape along the tool path to create a tool passage area,
For the arc part,
Dividing the inside and outside of the tool path ;
For the outside of the tool path, create a tool passage area by sweeping the tool cross-sectional shape along the tool path,
For the inside of the tool path, the tool shape is divided into a part whose radius is equal to or smaller than a part whose radius is larger than the radius of the arc part of the tool path,
For the part where the radius of the tool shape is the same as or smaller than the radius of the arc part of the tool path, create a tool passing area by sweeping the tool cross-sectional shape along the tool path, and then connect each tool passing area And create a tool passage area of the arc part,
A tool passing area model is created by connecting the created tool passing area of the straight part and the tool passing area of the arc part in accordance with the movement order of the tool on the tool path. Modeling method .

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