Patent Application
20200376756
The present invention relates to a method for producing a three-dimensional shaped product by joining a top undercut region and a bottom interior space-forming region, wherein, after lamination, sintering and cutting of the bottom interior space-forming region are carried out first, lamination and sintering of the top undercut region are carried out.
Three-dimensional shaped products which is formed according to lamination with a powder while a squeegee is traveling, sintering with irradiation of a laser beam or an electron beam and cutting by a traveling cutting tool, include three-dimensional shaped products with a construction in which a top undercut region, i.e. the undercut region having the lower side formed by lamination and sintering, is joined with a pipe-shaped region forming the interior space on the lower side.
Control for three-dimensional shaping is usually accomplished by a CAD/CAM system, but for creation of a cutting path for a cutting tool by the CAD/CAM system, it is presupposed that the regions containing the cutting path are regions in which the cutting tool can be inserted.
For formation of an enclosed interior space of the three-dimensional shaped product, therefore, such as the inner side of a water conduit, it is considered to be impossible to automatically create the cutting path in the interior space by the CAD/CAM system unless the cutting tool can be inserted from the start.
In light of this problem, Patent Document 1 proposes using a laser light beam for interior cutting of the three-dimensional shaped product by the CAD/CAM system with adjustment of the focal point of the light beam, thereby avoiding using the cutting tool to create the cutting path in the interior space.
In contrast, in Patent Document 2, a horizontal cutting path is formed in the three-dimensional shaped product which forms the interior space, by the following steps set by the CAD/CAM system.
(1) An imaginary horizontal plane, i.e. a planned cutting plane, is defined at an intermediate location between the top edge and the bottom edge of the interior space.
(2) A horizontal cutting path is created in the lower region of the planned cutting plane.
(3) A horizontal cutting path is created in the upper region of the planned cutting plane.
(4) Upon reaching the stage of cutting the horizontal cutting path located at the top edge within the horizontal cutting path of (2) above, a command to terminate cutting on the planned cutting plane of (1) above is set, and both horizontal cutting paths are joined by a command to progress to cutting of the horizontal cutting path located on the bottom edge within the horizontal cutting path of (3) above.
However, it is essential to create a special program for joining of both horizontal cutting paths at the top edge and bottom edge, as in (4) above.
Furthermore, the undercut region is usually present on the upper side of the planned cutting plane, and when the inner surface of the undercut region is cut, the cutting tool necessarily switches from the cutting portion on the upper side to the undercut cutting portion, making it unavoidable for the cutting width to be a small cutting width.
In step (3) above, however, the same cutting width is set as in step (2) above, and no consideration is given to switching of the cutting tool to an undercut cutting tool.
When a process is employed like the present invention, wherein the top undercut region and the bottom interior space-forming region are separately produced and both regions are joined, there is no need to create a planned cutting plane as in Reference 2, because the top edge of the interior space region on the lower side is opened.
However, when cutting with the side being the location of the top edge of the interior wall section of the region forming the interior space is carried out as final stage cutting step, the CAD/CAM system progresses to a step of automatically cutting a plane at the opening at the top edge in the horizontal direction by a program provided by the system itself.
Needless to mention, such cutting of the opening edge is unnecessary and meaningless, and is also a major hindrance in terms of accomplishing efficient three-dimensional shaping.
It is an object of the present invention to provide a method for efficient shaping of a three-dimensional shaped product by joining of a top undercut region and a lower side interior space-forming region without cutting in the horizontal direction at an opening located at the top edge of the interior space.
In order to solve the aforementioned problem, the present invention comprises following basic constructions (a) and (b).
(a) A method for producing a three-dimensional shaped product based on lamination with a powder while a squeegee is traveling, sintering of the laminated layer by irradiation with a laser beam or an electron beam, and cutting of the sintered layer with traveling a cutting tool, wherein a top undercut region and a bottom interior space-forming region are joined by following steps:
1. A CAD/CAM system sets the following steps.
(1) Creation of a shape of the top undercut region that has a bottom edge opening, and creation of a shape of the bottom interior space-forming region that has a top edge opening.
(2) Creation of a horizontal cutting path based on each prescribed location of a cutting blade of the cutting tool, on an interior wall section in the region on a lower side forming the interior space, at each location in order toward the upper side from a location of the bottom edge or a location of a position apparently near to the bottom edge of the interior wall section, with a cutting width of the cutting blade as an unit.
(3) When the location of the horizontal cutting path created in order in step (2) above has reached the location of a final stage, which is the location of the opening top edge or a location below the location of the top edge by a shorter distance than the cutting width, setting of a command for further lamination at the location of the top edge.
(4) A command for joining the bottom edge of the undercut region and the top edge of the interior space-forming region.
2. Lamination and sintering in the lower region based on step 1(1) above.
3. Cutting the interior wall section along the horizontal cutting paths created by steps 1(2) and 1(3) above.
4. Lamination and sintering in the undercut region based on steps 1(1) and 1(4) above.
(b) A method for producing a three-dimensional shaped product based on lamination with a powder while a squeegee is traveling, sintering of the laminated layer by irradiation with a laser beam or an electron beam, and cutting of the sintered layer with traveling a cutting tool, wherein a top undercut region and a bottom interior space-forming region are joined by following steps:
1. A CAD/CAM system sets the following steps.
(1) Creation of a shape of the top undercut region that has a bottom edge opening, and creation of a shape of the bottom interior space-forming region that has a top edge opening.
(2) Creation of a horizontal cutting path based on each prescribed location of a cutting blade of the cutting tool, on an interior wall section in the region on a lower side forming the interior space, at each location in order toward the upper side from a location of the bottom edge or a location of a position apparently near to the bottom edge of the interior wall section, with a cutting width of the cutting blade as an unit.
(3) When the location of the horizontal cutting path created in order by step (2) above has reached the location of the opening top edge or a location below the location of the top edge by a shorter distance than the cutting width, creating a horizontal cutting path as a final stage at an upper side by the cutting width for either above location, and setting of a command for terminating cutting operation at the horizontal cutting path of the final stage for the cutting tool.
(4) A command for joining the bottom edge of the undercut region and the top edge of the interior space-forming region.
2. Lamination and sintering in the lower region based on step 1(1) above.
3. Cutting the interior wall section along the horizontal cutting paths created by steps 1(2) and 1(3) above.
4. Lamination and sintering in the undercut region based on steps 1(1) and 1(4) above.
In the basic constructions (a) and (b), if the bottom interior space-forming region has an opening at the top edge, then the horizontal cutting path may be set as in step 1(2) without setting the planned cutting plane as in Patent Document 2.
Even if the planned cutting plane is not set, it is not necessary to create a special program in order to join the horizontal cutting path on the lower side and the horizontal cutting path on the upper side of the planned cutting plane, as in the construction of Patent Document 2.
However, as is explained under Background Art above, with current CAD/CAM systems, the horizontal cutting path is simply set and cutting is carried out based on the setting, and when the final stage is cutting at the opening where the side is the location of the top edge of the lower region, the CAD/CAM system is programmed to automatically effect control for cutting in the horizontal direction at the opening at the top edge at the stage where the final stage of cutting has been completed, and when cutting is carried out based on the programming, the cutting constitutes a hindrance against efficient shaping.
In the basic construction (a), when cutting has been carried out along the horizontal cutting path of the final stage at the uppermost side in step 1(3), the command for further lamination at the opening of the top edge is set as a subsequent step.
According to the command, the CAD/CAM system judges that further cutting has been carried out after the further lamination and sintering in the region on the upper side of the opening, and judges that the cutting at the opening is not the final stage cutting, thus it is avoided to cut in the horizontal direction at the opening.
In the basic construction (b), a horizontal cutting path on a location at upper side of the location of the top edge by the cutting width of the cutting tool or a horizontal cutting path on a location at upper side of the location of the top edge a shorter distance than the cutting width, i.e. a horizontal cutting path on a location at upper side of the horizontal cutting path by the cutting width at the final stage of the basic construction (a) is set as the cutting path of the final stage, then a command is set for the cutting tool to terminate the cutting operation in the cutting path at the final stage.
According to the terminating command, in the basic construction (b), it is possible to avoid automatic cutting in the horizontal direction at the final stage by the CAD/CAM system, since cutting is not carried out at the final stage.
Furthermore, with the horizontal cutting path located at the second higher point, i.e. the horizontal cutting path at the final stage of the basic construction (a), it is possible for cutting of the opening where the side is as the location of the top edge in the lower region to be the actual cutting step at the final stage.
Additionally, when cutting for an inner surface of the undercut region is carried out as in the embodiment described below, the cutting tool for the undercut region sets a cutting path suited for the cutting width, and the problem does not arise as in Patent Document 2 which ignores the difference between both cutting widths.
It shows selection of a region apparently near the bottom edge of the interior wall section as the start location for the horizontal cutting path in step 1(2).
It shows selection of the bottom edge of the interior wall section as the start location of the horizontal cutting path in step 1(2).
As shown by
Note that N in
1. A CAD/CAM system sets the following steps.
(1) Creation of a shape of the top undercut region 1 that has a bottom edge 11 opening, and creation of a shape of the bottom interior space-forming region 2 that has the top edge 23 opening.
(2) Creation of the horizontal cutting path 3 based on each prescribed location of a cutting blade of a cutting tool, on an interior wall section 21 in the region 2 on a lower side forming the interior space, at each location in order toward the upper side from a location of the bottom edge or a location of a position apparently near to the bottom edge of the interior wall section 21, with the cutting width of the cutting blade as an unit.
(3) When the location of the horizontal cutting path 3 created in order in step (2) above has reached the location of a final stage, which is the location of the opening top edge 23 or a location below the location 23 of the top edge by a shorter distance than the cutting width, setting of a command for further lamination at the location 23 of the top edge.
(4) A command for joining the bottom edge 11 of the undercut region 1 and the top edge 23 of the interior space-forming region 2.
2. Lamination and sintering in the lower region based on step 1(1) above.
3. Cutting the interior wall section 21 along the horizontal cutting paths 3 created by steps 1(2) and 1(3) above.
4. Lamination and sintering in the undercut region 1 based on steps 1(1) and 1(4) above.
In step 1(3) above, since the command for lamination at the opening of the top edge 23 is set, the step of cutting the opening in the horizontal direction, corresponding to be meaningless and a hindrance to working efficiency is not carried out.
Additionally, since lamination and sintering steps in the top undercut region 1 are actually carried out according to the command as the subsequent stage after cutting for the side section of the opening of the top edge 23, then setting of the command does not constitute any particular hindrance in terms of efficiency of shaping.
As shown by
Note that N in
1. The CAD/CAM system sets the following steps.
(1) Creation of the shape of the top undercut region 1 that has the bottom edge 11 opening, and creation of the shape of the bottom interior space-forming region 2 that has the top edge 23 opening.
(2) Creation of the horizontal cutting path 3 based on each prescribed location of the cutting blade of the cutting tool, on the interior wall section 21 in the region 2 on the lower side forming the interior space, at each location in order toward the upper side from the location of the bottom edge or a location of a position apparently near to the bottom edge of the interior wall section 21, with the cutting width of the cutting blade as the unit.
(3) When the location of the horizontal cutting path 3 created in order by step (2) above has reached the location 23 of the opening top edge or a location below the location 23 of the top edge by a shorter distance than the cutting width, creating the horizontal cutting path 30 as a final stage at the upper side by the cutting width for either above location, and setting of a command for terminating cutting operation at the horizontal cutting path 30 of the final stage for the cutting tool.
(4) A command for joining the bottom edge 11 of the undercut region 1 and the top edge 23 of the interior space-forming region 2.
2. Lamination and sintering in the lower region based on step 1(1) above.
3. Cutting the interior wall section 21 along the horizontal cutting paths 3 created by steps 1(2) and 1(3) above.
4. Lamination and sintering in the undercut region 1 based on steps 1(1) and 1(4) above.
In step 1(3) above, it is possible to carry out cutting for the opening of the top edge 23 in the horizontal direction, since the cutting does not constitute cutting at the final stage by setting the command for terminating cutting along the horizontal cutting path 30 at the final stage which is positioned at upper side of the uppermost cutting path of the basic construction (a) by the cutting width, and corresponds to the uppermost location, and so cutting is carried out along the horizontal cutting path 3 at a second location from the upper side.
Furthermore, since the terminating command is carried out immediately as the subsequent step after completing cutting at the second location from the upper side, the terminating command does not constitute a hindrance against efficient shaping.
Although the uppermost horizontal cutting path 3 stands on idle rolling of the cutting tool, in step 1(3), idle rolling is not carried out actually by the terminating command.
For “each prescribed location of the cutting blade of the cutting tool” in each respective step 1(2) of the basic constructions (a) and (b), it is possible to select any location from the top edge to the bottom edge of the cutting blade, but usually a central location or the bottom edge location will be selected.
So, when the center location of the cutting blade is the reference for the start location of the horizontal cutting path 3 in each respective step 1(2) of the basic constructions (a) and (b), the “location of the bottom edge of the interior wall section 21” must necessarily be selected.
On the other hand, when the location of the bottom edge of the cutting blade is the reference, it is possible to select the “location of the bottom edge or a location near the bottom edge of the interior wall section 21.”
In the basic constructions (a) and (b), it is not always necessary to carry out cutting of the lower side that forms the interior wall section 21 in the undercut region 1.
However, for the embodiment consisting of the following steps, as in
Note that N′ in
1. The following steps are set by the CAD/CAM system.
(1) Setting of the location of the highest opening 12 corresponding to the uppermost location that allows inserting an undercut cutting tool in a slanted direction, among openings formed in order on the upper side by lamination and sintering.
(2) Creation of the horizontal cutting path 3 on the interior wall section 21 of the undercut region 1, based on a prescribed location of the cutting blade of the undercut cutting tool, at each location along a slanted direction based on successive undercut angles, from the location 11 at the bottom edge of the undercut region 1, with an unit of the cutting width of the cutting blade.
(3) Continuous creation of the horizontal cutting path 3 in step (2) above, until the location of the horizontal cutting path 3 successively formed by step (1) above reaches the location at the final stage which is the location of the highest opening 12 set by step (2) above or a location below the location of the highest opening 12 by a shorter distance than the cutting width of the undercut cutting tool.
2. Lamination and sintering in the region from the bottom edge 11 of the undercut region 1 to the highest opening 12.
3. Cutting of the interior wall section 21 in the undercut region 1 along the horizontal cutting paths 3 created by steps 1(2) and (3) above.
4. Lamination and sintering of the highest opening 12 in the undercut region 1 that forms an upper region 13.
In this embodiment, when cutting has been carried out by the undercut cutting tool along the horizontal cutting path 3 where the side is the highest opening 12, since the cutting corresponds to cutting at the final stage, the CAD/CAM system must issue a command for cutting of the horizontal plane of the highest opening 12 and the cutting must actually be carried out.
However, when the opening region at the top edge 23 is extremely narrow, there is no major hindrance to the working efficiency even if cutting of the top edge surface 23 has been carried out.
Nevertheless, when the CAD/CAM system has set the command for further lamination at the location of the highest opening 12, and when the horizontal cutting path 30 at the final stage of step 1(3) above has been created, it is possible to avoid cutting of the highest opening 12 in the horizontal direction similar to the case of the basic construction (a).
The invention will now be explained by an example.
For the Example, as shown in
For this embodiment, it is possible to efficiently cut the bottom face in the interior space-forming region 2 by a flat rotation disc at the bottom edge of the cutting tool.
According to the present invention, for shaping of the three-dimensional shaped product constituting the top undercut region and the bottom interior space-forming region, it is possible to avoid cutting of the top edge surface in the interior space-forming region and to accomplish efficient cutting of the interior wall section, and therefore the invention has very high practical value.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-098721 | May 2019 | JP | national |
