Apparatus for making hollow extrusion dies

An apparatus for making a hollow die set consisting of a male and female die members with their respective male and female die bearing surfaces spaced apart from one another in a predetermined shaped and mating relationship, from a solid male and a hollow female die blanks, respectively, said male die blank being in the form of an annular block having a base flange and a columnar boss portion centrally projected therefrom, said boss portion being formed near its top with an outwardly projected annular flange to be machined to provide said male die bearing surface, said female die blank being in the form of a cup-shaped block having a cylindrical portion extending downwardly and at its top portion an opening formed with an inwardly projected annular rim to be machined to provide said female die bearing surface, said apparatus comprising:

• a first jig member for securely and interchangeably mounting said male and female die blanks in a predetermined position thereon;
• a worktable for securely mounting said first jig member thereon;
• a wire-cut EDM electrode head assembly displaceable relative to said worktable and having a plurality of wire guide members for spanning and axially transporting a continuous wire electrode in a fixed path of generally U form at an end portion of said assembly, said path including a predetermined stretch of the axially transported wire electrode constituting an axially moving EDM wire-cutting edge for machining said outwardly projected annular flange to provide said male die bearing surface and for machining said inwardly projected annular rim to provide said female die bearing surface;
• and
• a second jig member for securely mounting on said male die blank when the latter is securely mounted on said first jig member in said predetermined position for providing a reference surface to be engaged by said predetermined stretch of the axially transported wire electrode for machining said outwardly projected annular flange in said male die blank and said inwardly projected annular rim in said female die blank in said predetermined position.

An apparatus for making a hollow die set consisting of a male and female die members with their respective male and female die bearing surfaces spaced apart from one another in a predetermined shaped and mating relationship, from a solid male and a hollow female die blanks, respectively, said male die blank being in the form of an annular block having a base flange and a columnar boss portion centrally projected therefrom, said boss portion being formed near its top with an outwardly projected annular flange to be machined to provide said male die bearing surface, said female die blank being in the form of a cup-shaped block having a cylindrical portion extending downwardly and at is top portion an opening formed with an inwardly projected annular rim to be machined to provide said female die bearing surface, said base flange of the male die blank having an upper rim shaped to be snugly fitted with a lower end of said cylindrical portion of the female die blank, said apparatus comprising:

• a first jig member for securely and interchangeably mounting said male and female die blanks in a predetermined position thereon, said first jig member including a disk- or plate form base and a central projection,
• a worktable for securely mounting said first jig member thereon;
• a wire-cut EDM electrode head assembly displaceable relative to said workpiece and having a plurality of wire guide members for spanning and axially transporting a continuous wire electrode in a fixed path of generally U form at an end portion of said assembly, said path including a predetermined stretch of the axially transported wire electrode constituting an axially moving EDM wire-cutting edge for machining said outwardly projected annular flange to provide said male die bearing surface and for machining said inwardly projected annular rim to provide said female die bearing surface;
• and
• a second jig member for securely mounting on said male die blank when the latter is securely mounted on said first jig member in said predetermined position for providing a reference surface to be engaged by said predetermined stretch of the axially transported wire electrode for machining said outwardly projected annular flange in said male die blank and said inwardly projected annular rim in said female die blank in said predetermined position, said second jig member being in the form of a cup-shaped block having a cylindrical portion extending downwardly and at its top portion an annular opening defined by a circular wall constituting said reference surface,
• said central projection of the first jig member having an upper rim shaped to be snugly fitted with a lower end of said cylindrical portion of the second jig member and with said lower end of the cylindrical portion of said female die blank,
• said lower end of the cylindrical portion of said second jig member being snugly fitted with said upper rim of the flange of said male die blank.