JPH07152821A - Designing method and design support system for mold - Google Patents

Abstract

PURPOSE:To improve the designing quality and to shorten the designing time of a mold by inputting the shape of a product and the boundary surface between an external mold being a surface where the core touches the engraved surface of the external mold via a through hole of the product when the core is placed at the engraved part of the external mold and a core to a computer and then deciding the shapes of the external mold and the core based on those information inputted to the computer. CONSTITUTION:This system consists of the input/output devices 20 and 50, a processor 70 and e display device 50. A designer operates the device 20 to design 8 mold while looking at the shape of a product, etc., shown on the screen of a CRT device 54. Meanwhile the designed shape of the mold is stored in an auxiliary recording device 40 as data or outputted on the paper by a herd copy 22 or a plotter 24. The processor 70 consists primarily of a computer which includes a CPU, a ROM end a RAM. The ROM previoulsy stores 8 program to support the designing of the mold, and the CPU carries out this designing support program by a command of the designer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold design method and a design support system, and more particularly to casting a product in which a hollow portion communicates with the atmosphere through a through hole of a meat portion by using a core. The present invention relates to automation of the work for obtaining the engraving shapes of the outer mold and the core mold of.

[0002]

2. Description of the Related Art For example, cast products such as a cylinder block of an automobile engine, an intake manifold connected to the cylinder block, an exhaust manifold, etc. are manufactured by, for example, FIGS.
As shown in the sectional view, the hollow portion has a portion communicating with the atmosphere through the through hole of the meat portion.

This type of casting is cast using an outer die, a core, a skirting board and the like. Therefore, when designing a mold for this type of cast product, it is necessary to determine the shape of the outer mold and the shape of the core mold, respectively. Here, the "outer mold" is a mold in which a cavity for molding the outer shape of the product, a casting design part, etc. are formed. It is what is done. Further, the "core mold" is a mold in which a cavity portion for molding the surface shape of the core is formed, and when the skirting board is used, the cavity portion for molding the surface shape of the skirting board is also formed. It is what is formed. Then, conventionally, a designer independently obtains an outer die shape that is an outer die engraving shape and a core die shape that is an inner die engraving shape from a drawing showing a product shape. It was

[0004]

However, it takes time and it is difficult to maintain a constant design quality because the designer has always required the outer shape and the core shape from the product drawing. Is.

In designing a mold using a core, the relationship between the outer mold design dimension and the core mold design dimension is important. This is because the relationship affects, for example, the wall thickness accuracy of the cast product. However, conventionally, as described above, the outer mold shape and the core mold shape have been independently obtained by the designer, and it has not been designed while checking the mutual dimensional relationship. Therefore, even if casting is performed in accordance with the die design drawing, sufficient wall thickness accuracy may not be obtained in the cast product, and the die may have to be corrected many times.

Against this background, the invention of claim 1 provides a method for designing an outer die shape and a core die shape from a product shape by a computer, thereby improving the quality of die design and designing time. The task was to reduce the number of times.

The invention of claim 2 provides a system for supporting the work of designing the outer shape and the core shape from the product shape, thereby improving the quality of the mold design and shortening the design time. This was done as an issue.

[0008]

In order to solve each of the problems, the invention of claim 1 is for casting a product in which a hollow portion communicates with the atmosphere through a through hole of a meat portion by using a core. A method of designing an outer mold and a core mold, wherein the shape of the product and a through hole of the product when the core is arranged in an engraved portion of the outer mold for a computer. Input the outer mold and the boundary surface of the core, which is the surface in contact with the engraved surface of the outer mold, through the computer, based on the information entered, the outer mold shape and the core mold shape, respectively. It is supposed to be decided.

In the present invention, the act of "inputting by the designer" means all the actions that result in information being supplied to the computer in accordance with the intention of the designer, and the designer uses the input means. It is not limited to the case where information is directly supplied to the computer via the, for example, the designer inputs only the transfer command to the computer through the input means, and the computer responds to the transfer command and is stored in advance from the external storage device. This also includes the case of reading information and loading it into the computer.

In the present invention, the term "core" means, of course, a core without a skirting board, but in the case of using a skirting board, the core including the skirting board is used. Shall mean.

According to the second aspect of the present invention, the work for designing an outer die and a core die for casting a product in which the hollow portion communicates with the atmosphere through the through hole of the meat portion using the core is supported. In the system, (a) the shape of the product and a surface where the core contacts the engraved surface of the outer mold through the through hole of the product when the core is placed in the engraved portion of the outer mold. Input means capable of inputting a boundary surface between a certain outer mold and the core, respectively (b)
Processing means for determining the outer shape and the core shape based on the input information, and (c) display means for displaying the input result and the processing result on the screen are included.

The inventions of the respective claims can be applied not only to the die casting method but also to, for example, the green sand casting method.

[0013]

If the outer shape and the core shape are obtained from the product shape by the computer, the design quality is improved and the design time is shortened. Moreover, even a complex process for the designer can be performed easily and quickly by a computer, so the dimensional relationship between the outer die shape and the core die shape, that is, the actual wall thickness of the cast product, etc. can be accurately reflected. It is possible to design while doing so.

Therefore, in the designing method according to the first aspect of the present invention, a computer is used to determine the product shape and the boundary surface between the outer mold and the core, which is the surface which the two come into contact when the core is placed in the outer mold. The outer die shape and the core die shape are respectively determined based on the above.

The outer shape and the core shape can be determined by a computer as follows, for example. That is, a computer obtains a line of intersection between the product shape (surface) and the boundary surface between the outer die and the core, and the line of intersection divides the product shape into an outer shape and an inner shape. While the outer die shape (outer die engraving shape) is obtained from the inner die shape, the core die shape (core die engraving shape) can be obtained from the inner shape and the boundary surface.

[0016] Further, it is possible to obtain the outer mold shape and the core mold shape by a computer so that a preset clearance is secured at the boundary surface between the outer mold and the core. For example, a computer creates a pair of boundary surfaces that realize a preset clearance on the basis of the boundary surfaces of the outer mold and the core, and obtains a pair of intersection lines that intersect the pair of boundary surfaces and the product shape. , The product shape is divided into an outer shape and an inner shape by the pair of intersecting lines, and the outer shape is obtained by connecting the outer one of the pair of boundary surfaces with the product outer shape, while the pair of boundary surfaces is obtained. The core shape can be obtained by connecting the inner shape and the inner shape of the product.

Especially, if the product shape, the outer die shape, the core die shape, etc. are mainly represented in the computer by using a solid model, the clearance and the interference between the outer die and the inner die. , Undercut, inclusion relations, etc. can be checked easily and accurately.

In the design support system according to the second aspect of the present invention, the processing means determines the outer shape and the core shape based on the product shape input by the input means and the boundary surface between the outer mold and the core. Each is decided. Further, the display unit displays the input result and the processing result on the screen.

[0019]

As is apparent from the above description, according to the invention of each claim, the outer shape and the core shape are automatically obtained from the product shape without any design variation, so that the design quality is improved. It is possible to obtain an effect that the design time is shortened as well as being improved.

Further, according to the inventions of the respective claims,
From the product shape, it is possible to design while accurately reflecting the mutual dimensional relationship between the outer shape and the core shape, so the accuracy of the mold design is improved, and the time and labor required for mold correction can be omitted. Therefore, it is possible to easily shorten the period from the design of the cast product to the production.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, each invention of claim 1 or 2 will be concretely described based on illustrated embodiments.

FIG. 3 shows the hardware configuration of the system that supports the design of the mold. This design support system is configured to include an input / output device, a processing device, and a display device. The input / output device is, for example, an input device 20 such as a keyboard 10, a mouse 12, a light pen (or a stylus pen of a digitizer) 14, a joystick 16, a dial (function selecting means) 18, and the like.
Or an output device 30 such as a hard copy 22 or a plotter 24
Or magnetic disk device 32, magnetic tape device 34, CD
-It is configured to include the auxiliary storage device 40 such as the ROM device 36. The display device 50 includes a graphic controller 52 mainly composed of a computer and a CRT device 54.
And so on.

By using this design support system, a designer can design a mold by operating the input device 20 while looking at the product shape or the like displayed on the screen of the CRT device 54. Further, the designed mold shape can be stored as data in the auxiliary storage device 40 and saved, or can be output on paper by the hard copy 22 or the plotter 24.

The design support system is based on the transmission line 6
It is connected to another system (not shown) via 0 and cooperates with each other to form a network.

The processing unit 70, as shown in FIG.
A computer 78 including a U 72, a ROM 74 and a RAM 76 is mainly configured. A program for design support is previously stored in the ROM 74, and the CPU
72 executes this design support program in accordance with a command from the designer. The design support program may be stored in the auxiliary storage device 40 instead of being stored in the ROM 74, and may be read out from the storage device 40 and stored in the RAM 76 when necessary, and the CPU 72 may read out and execute the program.

A mold design program is included in this design support program, and the contents of this program will be described below with reference to the flow charts of FIGS.

This program is, for example, a casting having a hollow portion such as a cylinder head of an automobile engine, an intake manifold, an exhaust manifold, etc., and the hollow portion having a portion communicating with the atmosphere through a through hole of a meat portion (that This is for automatically performing the mold design for an example of the cross section (see FIG. 7). Specifically, as shown in FIG. 5, in this type of casting, the core passes through the through hole of the meat portion and indirectly contacts the outer mold through the skirting board, that is, the portion where the skirting board is used, As shown in FIG. 6, there is a portion where the core directly contacts the outer mold, that is, a portion where the skirting board is not used.

Here, the "mold design" specifically means an outer mold design and a core mold design. In order to automatically perform such mold design by a program, input of the product shape is required. In addition, the part where the core contacts the outer mold through the baseboard is the boundary surface between the outer mold and the baseboard, and the part where the core directly contacts the outer mold is the core and the outer mold. It is necessary to enter the boundary surface between and.

In addition to the original mold design, this program also automates the work of dividing the product shape. In the case of product division, a plane is input by the designer as in the case of the original mold design. In this case, the plane is input as a division plane of the product shape. Then, this program determines that the designer wants the original mold design when the input surface is not included in the product shape, and when the input surface is included in the product shape, the designer performs product division. It is so arranged that the work content can be automatically discriminated without having to wait for the identification command from the designer when it is determined that the user desires it.

Furthermore, this program carries out a collision check and an inclusion relation check for the figures once found, and if there is any inconvenience, it is automatically corrected, or if automatic correction is not possible. Is also urged to re-enter by the designer.

The contents of the programs shown in FIGS. 1 and 2 will be described below. For castings such as engine intake manifolds that have multiple through-holes in the meat, multiple independent boundary surfaces will be entered by the designer at the same time, but to simplify the explanation. In addition, assuming that the present casting has only one through-hole, the casting die design shown in FIG. 5 and the casting die design shown in FIG. 6 will be described as an example.

First, the mold design of the casting shown in FIG. 5 will be described as an example.

First, in step S10 of FIG. 1 (hereinafter simply referred to as S10; the same applies to other steps), the product shape is created as a solid model based on the operation of the input device 20 by the designer (FIG. 7). Column of S10). Next, in S20, a boundary surface between the outer mold and the core in a broad sense is created by a surface model as a reference boundary surface based on an operation by the designer. This time, since the core includes the skirting board, more precisely, the boundary surface between the outer mold and the skirting board is created as the reference boundary surface (see column S20 in FIG. 7).

In FIG. 7, three kinds of intersecting states of the product surface and the boundary surface are drawn. That is, as an example on the left side,
The case where a part of the boundary surface edge does not intersect the product surface is illustrated, and the case where the boundary surface intersects the product surface for the entire boundary edge is drawn as the center example and the right example, respectively. However, the example is an example in which the edge of the boundary surface intersects the product surface only once, and the example is an example in which the edge of the boundary surface intersects the product surface twice.

The boundary surface can be created as a closed surface or an open surface. The boundary surface can be newly created by the designer from the beginning or can be created by copying the surface of an existing solid model.

Then, in S30, a pair of boundary surfaces having a preset proper clearance is created based on the created reference boundary surface based on the operation of the designer (a pair is shown in the column of S30 in FIG. 7). Boundary surfaces are shown by a solid line and a broken line respectively). This is because the engraving shape of the skirting board support portion of the outer die and the engraving shape of the skirting board molding portion of the core die are respectively determined by taking into account manufacturing errors of the skirting board and the outer die in advance.

As a method of creating a pair of boundary surfaces having proper clearances, for example, the reference boundary surface is directly used as the first boundary surface, and the surface separated from the first boundary surface by the proper clearance in one direction is the second boundary surface. And a method of creating a pair of surfaces that are separated from the reference boundary surface by half the appropriate clearance in both directions as the first boundary surface and the second boundary surface.

The setting of the appropriate clearance is, for example,
It can be done by the designer or automatically by a computer. Further, it can be set uniformly regardless of the position on the boundary surface, or can be set differently depending on the position.

Then, in S40, the intersection lines of the product surface and the pair of boundary surfaces are obtained. Since the boundary surface is a pair, at least one pair of intersection lines is required. For example, in the example of FIG. 7, an open curve pair is obtained as an intersection line, in the example, a closed curve pair is obtained as an intersection line, and in the example, two closed curve pairs are obtained as intersection lines. .

Thereafter, in S50, it is determined whether or not each of the obtained intersecting line pairs is closed. This is because if there is an unclosed pair of intersecting lines, the subsequent steps will not be executed normally, and will be eliminated. For example, in the example of FIG. 7, since the intersecting line pair is open, the determination is NO, the process proceeds to S60, and error processing is performed.
This prompts the designer to re-enter data such as the boundary surface. On the other hand, in the example of FIG.
Since all the intersecting line pairs are closed, the determination is YES, and the process proceeds to steps S70 and subsequent steps in FIG.

In S70, it is determined whether or not there is only one closed intersection line pair. If there is only one pair of closed intersecting lines, the pair of intersecting lines identifies only the pair of face segments (closed plane or curved surface area),
That surface pair becomes the final boundary surface between the outer mold and the baseboard. Specifically, one of the surface segments forming the pair of surface segments is the engraving surface of the outer type skirting board supporting portion, and the other surface portion is the engraving surface of the core type skirting board forming portion. . However, when there are a plurality of closed intersecting line pairs, there are a plurality of surface segment pairs, and the execution result differs depending on which one is selected. Therefore, in this step, it is judged whether or not there is one closed intersection line pair, and if not, S8
At 0, the designer is allowed to specify the only face pair.

For example, in the example of FIG. 8, since there is only one closed intersecting line pair, the determination in S70 is YES, and the only face segment pair specified by the only intersecting line pair is the specific face segment. A pair is formed, and the process proceeds to steps S90 and below.
On the other hand, in the example of FIG. 8, since there are a plurality of closed intersecting line pairs, the determination in S70 is NO, the surface segment pair is specified by the designer in S90, and then the process proceeds to S90. In this example, it is assumed that the same face pair as in the example is specified.

In S90, it is determined whether the specific surface pair is included in the product shape solid model.

For example, in both the example of FIG. 8 and the specific surface segment pair, the product shape solid model is not included, so the determination is NO, and the product shape is divided by the specific surface segment pair in S100. Specifically, the product shape is a closed area defined by the line of intersection between the outer shape and the product shape of the two surface segments forming the specific surface segment pair,
It is divided into an inner surface segment and a closed region defined by the line of intersection of the product shape, and the first region is the product outer shape and the latter region is the product inner shape. Further, in this step, the outer shape of the product is obtained by combining the outer shape of the product with the outer surface of the product, and the inner shape of the product is combined with the inner surface of the product. A child-shaped engraving shape is required. At this time, the outer engraving shape is represented by a solid model, while the core engraving shape is represented by a surface model (S100 in FIG. 8).
Column)).

Then, in S110, the interference / inclusion relationship between the outer engraving shape and the core engraving shape is checked.

Originally, as shown in the upper side of FIG.
The outer shape of the product and the outer surface of the product, and the inner shape of the product and the inner surface of the product should be combined, but for some reason,
When the combination of connections is reversed and the outer shape of the product and the inner surface of the product are combined and the inner shape of the product and the outer surface of the product are combined, as shown in the center of the figure, the outer mold Interference occurs between the skirting board support part and the core type skirting board forming part. Further, for some reason, for example, when the inner shape of the product becomes larger than it should be, as shown in the lower side of the figure, the inner shape is originally included in the outer shape. Nevertheless, the inner shape protrudes from the outer shape to the outside, and the inclusion relation is not established. Therefore, in S110, the interference / inclusion relationship between the outer engraving shape and the core engraving shape is checked.

If interference does not occur and the inclusive relation is established, in S120, information having an entity in the inner region is added to the core-type engraved surface model. A solid model is created (see the column of S120 in FIG. 8). Then, in S130, the outer solid model data and the core solid model data are stored and stored in separate storage areas. This completes the one-time execution of this program.

On the other hand, as shown in error case 1 in FIG. 9, when interference occurs between the outer engraving shape and the core engraving shape, in S140, the coupling The combination is changed, and then the process returns to S100. If the inclusion relation is not established, error processing is performed in S150, and the designer is prompted to restart the program execution.

The mold design of the portion having the baseboard has been described above. Next, the mold design of the portion in which the core directly contacts the outer mold will be described. Further, a case where the surface designated by the designer is a boundary surface between the outer mold and the core and a case where the surface is a divided surface of the product shape will be described respectively.

First, in S10, the product shape is created as a solid model based on the operation of the input device 20 by the designer (see the column of S10 in FIG. 10). Next, S20
At, the boundary surface between the outer mold and the core or the division surface of the product shape is created by the surface model based on the operation by the designer, and is set as the reference boundary surface or the reference division surface, respectively. A reference boundary surface is created in the example of FIG. 10, and a reference division surface is created in the examples and. Since the core does not include the baseboard this time, the boundary surface between the core in the narrow sense and the outer mold is eventually created as the reference boundary surface in the example.

10 and 10 is also an example in which the boundary surface and the product surface intersect only once. In the example, the boundary surface and the product surface intersect twice (in the figure, two straight lines are on the same boundary surface). It is located and shows only the part that intersects with the product surface).

After that, in S30, a pair of boundary surfaces or divided surfaces having a preset proper clearance is created based on the created reference boundary surface or reference divided surface based on the designer's operation (FIG. 10 S30 column).

Then, in S40, the lines of intersection of the product surface and the pair of boundary surfaces or divided surfaces are obtained. For example, in the example and the example of FIG. 10, the pair of closed curves is obtained as the intersection line, and in the example, two pairs of the closed curves are obtained as the intersection lines.

Thereafter, in S50, it is determined whether or not each of the obtained intersecting line pairs is closed. For example, in the examples of FIG. 10 to FIG. 10, since all the intersecting line pairs are closed, the determination is YES, and the process proceeds to steps S70 and below in FIG.

In S70, it is determined whether or not there is only one closed intersection line pair. For example, in the example of FIG. 10 and only one closed intersecting line pair exists, the determination in S70 is YES, and the only face segment pair specified by the intersecting line pair is the specific face segment pair, The process proceeds to steps S90 and below. On the other hand, in the example of the figure,
Since there are a plurality of closed intersecting line pairs, the determination in S70 is NO.
Then, in S90, one of the plurality of surface segment pairs respectively specified by the intersecting line pairs is made a specific surface segment pair. In the example, the ring-shaped surface segment pair surrounded by the two intersecting line pairs is the specific surface segment pair.

In S90, it is determined whether the specific surface pair is included in the product shape solid model.

For example, in the example of FIG. 10, since the specific surface pair is not included in the product shape solid model, the determination in S90 is NO, and the process proceeds to S100 and subsequent steps.
Execution similar to that described above is performed. as a result,
For example, as shown in FIG. 11, an outer engraving shape and a core engraving shape are required.

On the other hand, when the specific surface pair is included in the product shape solid model, the determination in S90 is YES.
Becomes

In the example and in FIG. 10, since the specific surface pair is included in the product shape solid model, the determination is YE.
It becomes S, and the process proceeds to steps S160 and below.

In S160, the product surface is divided into two by a specific surface pair in the same manner as in S100.
As a result, for example, in the example of FIG.
As shown in, the outer engraving shape and the core engraving shape are required respectively.

Then, in S170, an interference check is performed. Specifically, when the divided product shapes are matched with each other in a regular relative positional relationship, it is determined whether or not interference occurs at the joint surface. For example, as shown in FIG. 12, if the product shapes are normal, and there is an appropriate clearance between the two when the divided product shapes are combined with a normal relative positional relationship, for some reason,
This is because if an error occurs in the combination of the divided portion of the product shape and the pair of boundary surfaces, interference may occur when the divided portions are combined.

If no interference occurs, S13
Moving to 0, solid model data is created for each divided part of the product shape. On the other hand, if interference occurs, the process proceeds to S180, the combination of the product shape dividing portion and the pair of boundary surfaces is changed, and then S1
Return to 60. In S160, the combination of the divided portion of the product shape and the pair of boundary surfaces is normalized. afterwards,
The process proceeds to S170 and subsequent steps.

After the outer die shape and the core die shape are respectively designed as described above, a parting surface suitable for the product shape and the core die shape is set for the outer die and the core die. Next, based on the solid model data of the outer mold and core mold divided by each parting plane, the outer mold and core mold are carved, and after the necessary mold modification, mass production Outer type and core type.

As is clear from the above description, in the present embodiment, the outer die design and the core die design are not independent of each other, but are performed by the computer while accurately considering the mutual relationship. It ensures a proper clearance between the outer mold and the core, which makes it possible to design a mold with a high degree of completion, easily shorten the time required for subsequent mold modification, and eventually lead time from design to production. It is possible to obtain the effect of easily shortening.

Further, in the present embodiment, since the mold design is mainly performed by using the solid model, the relation between the parts can be more improved as compared with the case where it is performed only by using the wire frame model or the surface model. Accurate examination is easy, and this also has an effect that the time required for subsequent mold modification can be easily shortened. However, it is possible to apply the invention of each claim to a mold design that does not use a solid model.

Further, in this embodiment, not only the original mold design (outer mold design and core mold design) but also product division can be performed, so that the work required in the design stage can be performed in a wider range. Automation is possible, which also has the effect of reducing the design time.

Moreover, in the present embodiment, the computer determines whether the designer should perform the original mold design or the product division, and the surface (boundary surface or division surface) input by the designer is included in the product. It is automatically performed depending on whether or not it is necessary, and it is not necessary for the designer to input the identification information into the computer one by one, and there is an effect that it is easy to use.

As is clear from the above description, in the present embodiment, the mold design method according to the invention of claim 1 is implemented by the mold design program of FIG. In addition, the input device 20 constitutes an example of the "input means" in the invention of claim 2 in cooperation with the part of the processing device 70 that executes 10 and 20 of FIG. 1, and S40 of the same figure to S160 of FIG. That is, the part that executes is configured as an example of “processing means”, and the display device 50 is configured as an example of “display means”.

Although the invention of each claim has been specifically described based on the illustrated embodiments, various modifications may be made based on the knowledge of those skilled in the art without departing from the scope of the claims. The invention of each claim can be implemented in the improved mode.

[Brief description of drawings]

FIG. 1 is a flowchart showing a part of a mold design program according to an embodiment common to the inventions of each claim.

FIG. 2 is a flowchart showing the remaining part of the mold design program.

FIG. 3 is a diagram showing a hardware device configuration of a design support system for executing the programs of FIGS. 1 and 2.

4 is a diagram conceptually showing the structure of the processing apparatus in FIG.

FIG. 5 is a front sectional view for explaining the relationship between the outer die, the core and the baseboard in a portion of the casting where the core contacts the outer die via the baseboard.

FIG. 6 is a front cross-sectional view showing a portion of the casting in which the core directly contacts the outer die.

FIG. 7 is a front sectional view for explaining the execution contents of the programs of FIGS. 1 and 2 in association with steps.

FIG. 8 is a front sectional view for explaining the execution contents of the programs of FIGS. 1 and 2 in association with steps.

FIG. 9 is a diagram for explaining the contents of S110 and 140 in FIG.

FIG. 10 is a front sectional view for explaining the execution contents of the programs of FIGS. 1 and 2 in association with steps.

FIG. 11 is a front sectional view for explaining the execution contents of the programs of FIGS. 1 and 2 in association with steps.

FIG. 12 is a diagram for explaining the contents of S170 and S180 in FIG.

[Explanation of symbols]

 20 input device 30 output device 40 auxiliary storage device 50 display device 70 processing device

Claims (2)

[Claims] 1. A method for designing an outer mold and a core mold for casting a product, the hollow part of which is communicated with the atmosphere through a through hole of a meat part, using a core, the method comprising: Between the shape of the product and the outer mold and the core, which is the surface where the core contacts the engraved surface of the outer mold through the through hole of the product when the core is placed in the engraving portion of the outer mold. A method for designing a mold using a computer, in which a boundary surface is input, and the computer determines each of the outer shape and the core shape based on the input information. 2. A system for supporting the work of designing an outer mold and a core mold for casting a product, the hollow part of which is communicated with the atmosphere through a through hole of a meat part, by using a core, Between the shape of the product and the outer mold and the core, which is the surface where the core contacts the engraved surface of the outer mold through the through hole of the product when the core is placed in the engraving portion of the outer mold. Input means capable of respectively inputting the boundary surface, processing means for respectively determining the outer shape and the core shape based on the input information, and display means for displaying the input result and the processing result on the screen. A mold design support system comprising: