JP2000024754A - Method for making mold by laminated molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molding method with laminated molding by executing a reverse treatment, by which a solid range is reversely changed into a space range in the cross sectional model at the initial stage, and also by which the space range is reversely changed into the solid range in the cross sectional model at the initial stage and regulating this reverse model as a mold cross sectional model. SOLUTION: The cross sectional model 300 at the initial stage corresponds to the outline shape of a casting or a casting model, and also corresponds to the first loop lines 301-302 normalized with a loop reference and the mold outer surface defining line, and also has the second loop lines 303, 304 normalized with the loop reference. The reverse treatment is executed in the direction reverse to the advancing direction of the first loop lines 301, 302 and in the direction reverse to the advancing direction of the second loop lines 303, 304 in the cross sectional model at the initial stage under the condition of the loop reference kept. At the time of hardening, e.g. the solidifying system by irradiating with a laser beam, the solidifying system by irradiating with an infrared or an ultraviolet, the solidifying system by contacting with curing agent, etc., are adopted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a mold by additive manufacturing.

[0002]

2. Description of the Related Art In recent years, additive manufacturing (JP-A-3-18353)
No. 0, USP (U.S. Pat. No. 4,247,508)), and a technique of forming a mold has attracted attention. In this additive manufacturing, a solidifiable substance such as resin-coated sand is used.
Then, an irradiation energy such as a laser beam is applied to the solidifiable substance to solidify the same, thereby forming a thin solidified layer. A large number of such solidified layers are sequentially laminated in the thickness direction to form a three-dimensional molded object.

[0003] According to such a lamination molding, there is an advantage that molding can be performed without requiring a draft even for a mold having a complicated shape. In this method, it is necessary to obtain a substantially two-dimensional mold section model corresponding to each section of the three-dimensional mold. In obtaining this mold section model,
It goes as follows. That is, a casting model 102 corresponding to the casting cast in the casting cavity of the mold is grasped (see FIG. 12A). Further, the casting model 102
A mold model 800 corresponding to the mold is grasped (see FIG. 12B). Next, the entire mold model 800 is sectioned at a predetermined pitch, and a large number of
0 (900 _{1 to} 900 _n ). Thus, the mold section model grasping step is completed. This step is performed by a computer program.

[0004] Next, a mold sectional model 9
00 based on ₁ was irradiated with irradiation energy of the laser beam or the like, thereby performing the solidification step of forming a large number of the solidified layer 1000 ₁ having a predetermined contour. Such a solidification process is performed up to the mold sectional model 900 _n . As a result, a large number of solidified layers 1000 _{1 to} 1000 _n based on each mold cross-sectional model 900 (900 _{1 to} 900 _n ) are sequentially stacked in the thickness direction, and a three-dimensional mold 1100 is formed.

[0005]

SUMMARY OF THE INVENTION The present invention provides a lamination molding method for forming a mold based on a mold cross section model grasping step having a procedure different from that of the above-described prior art mold cross section model grasping step. The task is to

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method of forming a mold by lamination molding, comprising: a step of grasping a mold cross-section model for obtaining a cross-sectional shape of a mold having a casting cavity which is a target for a casting. , A solidification step of forming a solidified layer corresponding to the mold cross-section model, and forming a mold by laminating the solidified layers in the thickness direction. The three-dimensional configuration model in which the cast product model having the shape to be placed is placed in the mold outer surface definition line that defines the outer surface shape of the mold is grasped, and the initial cross-sectional model having the real region and the cavity region in the three-dimensional configuration model is grasped. Invert the real region in the cross-sectional model to a hollow region, and obtain an inverted model in which the hollow region in the initial cross-sectional model is inverted to the real region. Dell is characterized in that defined as the template sectional model.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the method of the present invention can be described as the following (1) to (3). (1) A loop criterion is adopted in which one of the left side and the right side with respect to the traveling direction of the loop line is defined as a substantial area and the other is defined as a hollow area. (2) The initial cross-section model corresponds to the contour shape of the casting or the casting model and is defined by a first loop line defined by the loop reference and a second loop line defined by the mold outer surface definition line and defined by the loop reference. It has two loop lines.

In the reversing process, the reversal is performed by reversing the direction of the traveling direction of the first loop line and the direction of the traveling direction of the second loop line in the initial cross-sectional model while maintaining the above-described loop reference. (3) The solidifying step according to the method of the present invention is to form a solidified layer corresponding to the mold cross-sectional model. For solidification, for example, a method of solidifying by irradiating a laser beam, a method of solidifying by irradiating infrared rays or ultraviolet rays, a method of solidifying by contacting a curing agent, and the like can be adopted. A typical substance to be solidified is resin-coated sand coated with a thermosetting resin.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method of the present invention will be described below with reference to FIGS. First, a mold section model grasping step is performed. The goal of this process is to obtain a mold cross-section model which refers to the cross section of the mold with the casting cavity that is the object for the casting.

In this step, a product model 100 (see FIG. 1) actually mounted on the vehicle is grasped. Next, a casting model 102 (see FIG. 2) obtained by removing the bolt holes 101 and the like from the product model 100 is grasped. Further, as can be understood from FIG. 3, a frame 114 having a mold outer surface defining line 110 and an outer line 112 that defines the outer shape of the mold is defined,
The casting model 102 is arranged within the mold outer surface definition line 110 of the frame 114. Thus, the three-dimensional configuration model 200 (see FIG. 3) is grasped.

The three-dimensional arrangement model 200 is a casting model 1
02 and a mold outer surface defining line 11
And a cavity area 202 meaning a space inside zero. Next, the whole of the three-dimensional configuration model 200 is sliced by calculating a cross section at a predetermined pitch to obtain a large number of initial cross-section models 300 _{1 to} 300 _n (see FIG. 4). FIG. 5 shows _one initial cross-sectional model 300 among a number of initial cross-sectional models 300 _{1 to} 300 _n . This initial cross section model 3
Reference numeral 00 denotes a first loop line 301 corresponding to the outer contour shape of the casting model 102, a first loop line 302 corresponding to the inner contour shape of the casting model 102, and a first loop line 302 corresponding to the mold outer surface defining line 110. Two loop line 303 and frame 11
And a third loop line 304 corresponding to the outer line 112 of FIG.

In the loop reference of this embodiment, the loop lines 301 to 304 have a traveling direction (indicated by an arrow in FIG. 5), and the left side of the traveling direction of the loop lines 301 to 304 is a substantial area A (indicated by hatching). The right side with respect to the traveling direction of the loop lines 301 to 304 is defined as a cavity area B (white area without hatching).

Next, an inversion process is performed so that the real area A of the initial cross-sectional model 300 shown in FIG. In addition, inversion processing is performed so that the cavity region B of the initial cross-sectional model 300 becomes the real region A. Thus, an inverted model 400 shown in FIG. 6 is obtained. The above inversion processing will be further described. As can be understood from the comparison between FIG. 5 and FIG.
1, 302, an operation of reversing the traveling direction of the second loop line 303 is added. Furthermore, the outermost third loop line 30
Add an operation to ignore 4. Thus, the loop line 301
In the case of the reversal model 400 in which the directions of to 303 are reversed, the loop line 301
303 is defined as a substantial area A (area indicated by hatching) with respect to the traveling directions of
Since the right side with respect to the traveling direction of 03 is defined as the hollow area B (white area not hatched), an inverted model 400 in which the initial cross-sectional model 300 is inverted is grasped. The inverted model 400 is defined as the above-described mold cross-sectional model.

The creation of such an inverted model 400 is performed for each of the initial sectional models 300 _{1 to} 300 _n . Therefore, a large number of inverted models 400 (400 ₁ to 40
0 _n) is obtained. The above-described operation procedure is incorporated as a program in the memory area of the computer.

As described above, the inversion processing of this embodiment has the following features. ... In transition from the initial cross-sectional model 300 to the reverse model 400, the direction of the traveling direction of the first loop lines 301 and 302 and the direction of the traveling direction of the second loop line 303 are reversed. ... The outermost third loop line 304 in the initial sectional model 300 is ignored.

According to this embodiment, the "ON mode" for executing the above and the "OFF mode" for not executing the
And can be switched in the program.
Therefore, when executing the above modeling procedure, "ON mode"
If the “OFF mode” is set when the normal molding procedure is performed, the conventional additive manufacturing can be performed.

FIG. 11 shows a procedure in the mold section model grasping step described above. As shown in FIG.
At 104, the product model 100 is grasped, and step S1
At 06, the casting model 102 is grasped. Step S
At 108, it is determined whether the mode is the “ON mode”. If it is “ON mode”, the mold outer surface definition line 11 is
0, and at step S112, the three-dimensional arrangement model 200
Is set, and a cross section is calculated in step S114. In step S116, the initial cross-section model 300 is grasped. If the result of determination in step S118 is "ON mode", inversion processing is performed in step S120 to create an inversion model 400, and the process returns to the main routine.

If the result of determination in step S118 is not "ON mode", step S120 is not executed, and control returns to the main routine. Step S10
If the result of determination in step 8 is not “ON mode”, the process directly proceeds to step S114 without executing steps S110 and S112. The solidification step according to the present embodiment is performed in the same manner as in the related art. In the solidification step, first, a scatter layer made of a solidifiable substance such as resin-coated sand is formed.
Then, the scattered layer is irradiated with irradiation energy such as a laser beam so as to solidify the irradiated portion so as to obtain a substantial region A of the inverted model 400 which is a mold cross-sectional model. The irradiation energy such as a laser beam is not applied to the cavity region B of the inverted model 400.

As a result, a solidified layer 55 having a shape corresponding to the shape of the real region A of the mold cross-sectional model, that is, the inverted model 400 is formed. In the present embodiment, the solidification process as described above is sequentially repeated for a large number of inverted models 400 (400 _{1 to} 400 _n ). Thereby, a large number of solidified layers 5
5 (55 ₁ ~55 _n) sequentially laminated in the thickness direction, forming a three-dimensional mold 700 having a casting cavity 700c.

After the mold 700 is formed, a pouring step is performed to supply molten metal to the casting cavity 700c of the mold 700 (see FIG. 8). If the mold 700 is collapsed after the solidification of the molten metal, a casting 800 having a three-dimensional shape corresponding to the casting model 102 is obtained (see FIG. 9). The above-described solidification step will be further described with reference to FIG. An elevating board 60 is provided inside the fixed frame 6 so as to be able to move up and down in directions of arrows Y1 and Y2 by means of elevating means 61 such as a cylinder mechanism and a motor mechanism. The sand spraying device 7 for spraying the resin-coated sand 50c is in the direction of arrow C1 (the direction in which the sand is sprayed) and arrow C2.
It is provided so as to be horizontally movable in the direction (retreat direction). The sand spraying device 7 includes a container 70 containing the resin-coated sand 50c.
And a rotatable cutting roller 71 mounted on the bottom of the container 70 and a leveling plate 72 provided adjacent to the container 70.

Above the fixed frame 6, there is provided a scanner-type main irradiator 80 for irradiating the laser beam M. The main irradiation unit 80 has a built-in rotating mirror (not shown) for continuously changing the irradiation angle of the laser beam M. Main irradiation unit 8
A main laser oscillator 82 (CO ₂ laser, output: for example, 5 k
W to 10 kW).

The sand spreading device 7 is guided by a guide rail (not shown) and moves in the direction of arrow C1 to rotate the cutout roller 71. The groove 71c of the cutout roller 71 discharges the resin-coated sand 50c to the outside of the container 70. The resin is discharged from the outlet 75, whereby the resin-coated sand 50c is sprayed on the upper surface of the lift board 60 to form a sand layer 50 (thickness: 0.2 mm). Since the leveling plate 72 also moves in the same direction in conjunction with the container 70, the upper surface of the sand layer 50 is smoothed by the leveling plate 72. Thereafter, the sand spraying device 7 retracts in the direction of arrow C2. This ends the spraying of the sand. Next, a solidifying step of irradiating the laser beam M from the main irradiating section 80 to a predetermined area of the sand layer 50 is performed.

When the solidification step by the irradiation of the laser beam M is performed as described above, a solidified layer 55 in which the sand layer 50 is solidified is formed. When the solidification step including the spraying of the sand is repeated, the solidified layer 55 is gradually laminated in the thickness direction as described above (the number of laminated layers: for example, 200 to 100).
0), thereby obtaining a mold 700 as a three-dimensional structure.

In the mold section model grasping step according to the above-described embodiment, the mold outer surface defining line 110 and the outer line 112 are defined.
Although the casting model 102 is arranged in the frame 114 having the shape, the present invention is not limited to this, and only the mold outer surface defining line 110 may be defined, and the casting model 102 may be arranged therein.

[0025]

According to the method of the present invention, an inversion model is obtained by inverting a real region in an initial cross-sectional model into a hollow region, and inverting a hollow region in the initial cross-sectional model into a real region. Define as a cross-sectional model. A solidified layer is formed based on the mold cross-sectional model, and a mold is formed by stacking the solidified layers.

[Brief description of the drawings]

FIG. 1 is an external view of a product model.

FIG. 2 is an external view of a casting model.

FIG. 3 is an external view of a three-dimensional arrangement model.

FIG. 4 is an external view showing a state in which initial cross-sectional models obtained by cross-sectional calculations are stacked.

FIG. 5 is a plan view of an initial sectional model.

FIG. 6 is a plan view of an inverted model.

FIG. 7 is an external view showing a state in which solidified layers are stacked.

FIG. 8 is an external view of a mold.

FIG. 9 is an external view of a casting.

FIG. 10 is a configuration diagram showing a solidification step.

FIG. 11 is a flowchart showing a mold section model grasping step according to the embodiment.

FIG. 12 is a process chart according to the related art.

[Explanation of symbols]

In the figure, 102 is a cast product model, 110 is a mold outer surface definition line, 200 is a three-dimensional arrangement model, 300 is an initial cross-sectional model, 301 to 303 are loop lines, 400 is an inversion model,
700 indicates a mold, and 800 indicates a cast product.

Claims (2)

[Claims] 1. A mold cross-section model grasping step for obtaining a mold cross-section model showing a cross-sectional shape of a mold having a casting cavity to be molded with a casting, and forming a solidified layer having a shape corresponding to the mold cross-section model. Performing a solidification step, wherein the solidified layer is laminated in the thickness direction to form a mold. In the mold cross-section model grasping step, the casting or a casting model corresponding to the casting is subjected to a molding outer shape. Grasping the configuration model arranged in the mold outer surface definition line defining the mold, grasping the initial cross section model having the real region and the cavity region in the configuration model, and inverting the real region in the initial cross section model to the cavity region Processing, and obtains an inverted model in which the hollow area in the initial cross-sectional model is inverted to a substantial area, and the inverted model is referred to as the mold cross-sectional model. Mold molding method according to the layered manufacturing which is characterized by defined by. 2. The initial cross-section model according to claim 1, wherein one of a left side and a right side with respect to the traveling direction of the loop line is defined as a substantial area and the other is defined as a hollow area. A first loop line corresponding to the contour shape of the casting or the casting model and regulated by the loop reference, and a second loop line corresponding to the mold outer surface definition line and regulated by the loop reference. In the reversing process, the reversal is performed by reversing the direction of the traveling direction of the first loop line and the direction of the traveling direction of the second loop line in the initial cross-sectional model while maintaining the loop reference. Characteristic mold making method by additive manufacturing.