Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1998-06-16
2001-05-15
Grant, William (Department: 2121)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S182000, C700S118000
Reexamination Certificate
active
06233499
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for designing structures of molds by converting product data to solids using a 3-dimensional CAD system. More particularly, the present invention relates to a method for dividing each mold into two parts (cavity and core) when molds are designed using a 3-dimensional CAD system.
2. Description of the Prior Art
Generally, as shown in
FIGS. 20
to
23
, when a 3-dimensional CAD system is used for designing molds, a product solid (3-dimensional shape model data of an object product, created by a computer) (A′) (see
FIG. 20
) is put in a mold block solid (D′) such as a rectangular solid, which is equivalent to a nesting in a mold base, then removed from the mold block solid, thereby to form a cavity (E′) to become a product (an object formed with resin in the mold) in the mold block solid (FIG.
21
). Then, the mold block solid is divided into upper and lower parts at this cavity assumed as a boundary, thereby to form a cavity solid (F′) and a core solid (G′) (FIG.
23
). This dividing, however, includes many restrictions and problems when performed on a 3-dimensional CAD system. In other words, any of present CAD systems cannot cut such a mold block solid partially. When a mold block solid is cut unavoidably using such a present CAD system, therefore, the solid must be cut completely on its entire surface and then portions that should have not been cut must be put together after they are cut.
At present, for example, a general method for dividing such a mold block solid divides a rectangular solid along the cavity described above. In this case, at first, a surface (J) is added along a mold parting line and extended, thereby to divide the rectangular solid. The rectangular solid is thus divided all along the parting line of the mold repetitively (FIG.
22
). After this, necessary portions are put together, thereby to generate a cavity solid (F′) and a core solid (G′) finally to design the object mold (FIG.
23
).
A method for manufacturing molds using a 3-dimensional CAD system such way is disclosed in the official report of Unexamined Published Japanese Patent Application No. 8-4854 “Method for Manufacturing Molds”. The technology disclosed in the patent applies only to very simple structured molds to be divided only at a reference parting line (2) respectively. The technology does not disclose anything about a method for dividing a mold into a cavity and a core when the mold is designed for a complicated shape product.
When in designing a mold using a 3-dimensional CAD system described above in the prior art method for dividing molds, a surface is extended as shown in
FIG. 22 and a
portion (K) that should not be divided is also divided. And, when such a dividing is repeated, a rectangular solid is divided into many models. Furthermore, generally, there are very few of simple structured molds, each of which is divided at a reference parting line as disclosed in the official report of Unexamined Published Japanese Patent Application No. 8-4854. In many cases, molds are very complicated in structure and each of them has many parts (parting positions). Each of those molds is divided into a cavity and a core by repeating such the dividing of parts. Consequently, the more a mold is complicated in structure, the more the time and labor for dividing parts of the mold are needed.
Furthermore, in the prior art dividing method, when such a sharp shape (N) as a junction between an arc (L) and a surface (M) is left as shown in
FIG. 24
, the mold cannot be divided. In addition, since it is difficult to divide the mold on a free curved surface and many dividing and sewing operations are needed, the accuracy of product solid data itself is degraded.
SUMMARY OF THE INVENTION
Under such the circumstances, it is an object of the present invention to provide a method for designing molds, which can divide each mold into a cavity and a core easily when in designing the mold by converting product data to solids using a 3-dimensional CAD system.
It is another object of the present invention to provide a method for designing molds, which can easily divide any mold complicated in structure and formed so that a nesting is formed in part of a parting portion of the mold.
It is also another object of the present invention to provide a method for manufacturing thin and thick film formed product solids for which mold parting lines can be set easily when in designing a mold using a 3-dimensional CAD system and a recording medium which stores elements composing each of the product solids.
It is also another object of the present invention to provide a concrete method for dividing each mold into a cavity and a core using a 3-dimensional CAD system, an apparatus for designing molds using such a method, and a recording medium which stores procedures of such designing.
The method of the present invention for designing molds using a 3-dimensional CAD system is characterized as follows; forming a first cavity in a mold block solid by removing a product solid from the mold block solid; forming a second cavity by removing an element solid having a specified thickness from the mold block solid, the second cavity being provided at a parting portion of the mold block solid; and dividing the mold block solid into a cavity solid and a core solid along the second and first cavities.
A “solid” mentioned above means data created from, for example, surface data of a product so as to be handled by a CAD system as data having a thickness. Such data as a product shape is referred to as a product solid and such data as a mold block is referred to as a mold block solid. An element solid means a solid having a fixed thickness so as to form a cavity at a parting line of a mold, such as a thin film solid for forming a third cavity which is thin at a parting line of a hole to, for example, divide a hole of a product, a thick film solid for forming a fourth cavity having an enough thickness including a parting line (the parting line is formed by adding a piece solid later), such as a whole hole and a block around a complicated parting line. The second cavity formed with such an element solid means a cavity including both the third cavity formed with a thin film solid described above and the fourth cavity formed with a thick film solid.
The element solid can also be formed with a thin film solid having a thickness within a value that does not become an obstacle to a clearance of any mold. The element solid can also be formed with a thick film solid including a parting line of the object mold. The thick film solid is removed from the mold block solid, thereby to form the fourth cavity and the mold block solid is divided into a cavity solid and a core solid using the fourth and first cavities, then piece solids formed by dividing the thick film solid at a parting line of the mold are added to a portion of the cavity and/or core solid, exposed by the fourth cavity, thereby to design both cavity and core of the mold.
The method of the present invention for forming a thin film formed product solid (a product solid with a thin film) when in designing a mold using a 3-dimensional CAD system is characterized as follows; at first, a product solid is generated by modeling the shape of a product, then a thin film solid composing a parting line of the mold is added to the product solid, thereby to unite the product solid with the thin film solid. Furthermore, the method for forming a thick film formed product solid (a product solid with a thick film) is characterized as follows; at first, a product solid is generated by modeling the shape of a product, then a thick film solid covering at least part of a hole and/or a complicatedly structured parting portion of the product solid is added to the product solid, thereby to unite the product solid with the thick film solid.
The recording medium of the present invention stores data (program) including a product solid formed by modeling the shape of
Arent Fox Kintner Plotkin & Kahn
Bahta Kidest
Grant William
Sanyo Electric Co,. Ltd.
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