A dummy block for a metal extrusion press includes: a generally cylindrical base having a forward surface and an outwardly extending circumferential flange; an expandable collar coupled to the base, the collar having an inwardly extending circumferential rib abutting the circumferential flange; a plunger disc seated against the forward surface of the base and accommodated by the collar, and a plunger shaft extending through the plunger disc and coupled to the base.

A dummy block for a metal extrusion press includes: a generally cylindrical base having a forward surface and an outwardly extending circumferential flange; an expandable collar coupled to the base, the collar having an inwardly extending circumferential rib abutting the circumferential flange; a plunger disc seated against the forward surface of the base and accommodated by the collar, and a plunger shaft extending through the plunger disc and coupled to the base.

An extruded material includes a peripheral wall having a closed loop-shaped cross-section and defining a hollow, and a middle rib connected to an inner peripheral surface of the peripheral wall and dividing the hollow. The extruded material is provided with a corrected portion set at a predetermined portion in a longitudinal direction and subjected to correction processing, and an uncorrected portion not subjected to the correction processing. The peripheral wall is expanded outward with respect to an original shape of the uncorrected portion in the corrected portion. While the middle rib is curved with respect to an imaginary straight line connecting connecting portions connected with the peripheral wall at both end portions of the middle rib in the uncorrected portion, the middle rib has a smaller degree of curvature than the original shape of the uncorrected portion in the corrected portion.

An extruded material includes a peripheral wall having a closed loop-shaped cross-section and defining a hollow, and a middle rib connected to an inner peripheral surface of the peripheral wall and dividing the hollow. The extruded material is provided with a corrected portion set at a predetermined portion in a longitudinal direction and subjected to correction processing, and an uncorrected portion not subjected to the correction processing. The peripheral wall is expanded outward with respect to an original shape of the uncorrected portion in the corrected portion. While the middle rib is curved with respect to an imaginary straight line connecting connecting portions connected with the peripheral wall at both end portions of the middle rib in the uncorrected portion, the middle rib has a smaller degree of curvature than the original shape of the uncorrected portion in the corrected portion.

An apparatus for manufacturing a prismatic can includes a die configured to support a bar-shaped slug, a punch arranged on a horizontal axis of the die to reciprocate in a left and right direction so as to press the slug supported on the die, and a connecting rod between a driver configured to generate power and the punch to transmit the power generated by the driver to the punch. A cross-section of an edge of the punch in a direction of the die has a rectangular shape corresponding to a bottom surface of an impact can to be manufactured, and upper and lower areas of the punch are provided in an asymmetrical shape based on a horizontal axis center line.

An apparatus for manufacturing a prismatic can includes a die configured to support a bar-shaped slug, a punch arranged on a horizontal axis of the die to reciprocate in a left and right direction so as to press the slug supported on the die, and a connecting rod between a driver configured to generate power and the punch to transmit the power generated by the driver to the punch. A cross-section of an edge of the punch in a direction of the die has a rectangular shape corresponding to a bottom surface of an impact can to be manufactured, and upper and lower areas of the punch are provided in an asymmetrical shape based on a horizontal axis center line.

A dummy block for a metal extrusion press comprises: a generally cylindrical base having a forward surface and an outwardly extending circumferential flange; an expandable collar coupled to the base, the collar having an inwardly extending circumferential rib abutting the circumferential flange; a collar support coupled to the base and abutting the collar; and a moveable plunger coupled to the base and accommodated by the collar. The plunger has a rear surface configured to abut the forward surface of the base.

A dummy block for a metal extrusion press comprises: a generally cylindrical base having a forward surface and an outwardly extending circumferential flange; an expandable collar coupled to the base, the collar having an inwardly extending circumferential rib abutting the circumferential flange; a collar support coupled to the base and abutting the collar; and a moveable plunger coupled to the base and accommodated by the collar. The plunger has a rear surface configured to abut the forward surface of the base.

A method of controlling a hydraulic system, the hydraulic system including a ram cylinder unit having a cylinder and a ram, and a hydraulic pump and a reservoir used to supply hydraulic fluid to the cylinder, and hydraulically driving the ram using the hydraulic fluid so as to move against a specific load, the method includes determining what a present state is one of an initial state, a proportional steady state, and a later state, controlling the pumping rate, which is obtained by adding the flow rate corresponding to the volume loss due to the compression of the hydraulic fluid thereto, to control the ram in the initial state, and controlling the pumping rate, which is obtained by subtracting the flow rate corresponding to volume recovery of the hydraulic fluid due to the relief of compression of the hydraulic fluid therefrom, to control the ram in the later state.

A method of controlling a hydraulic system, the hydraulic system including a ram cylinder unit having a cylinder and a ram, and a hydraulic pump and a reservoir used to supply hydraulic fluid to the cylinder, and hydraulically driving the ram using the hydraulic fluid so as to move against a specific load, the method includes determining what a present state is one of an initial state, a proportional steady state, and a later state, controlling the pumping rate, which is obtained by adding the flow rate corresponding to the volume loss due to the compression of the hydraulic fluid thereto, to control the ram in the initial state, and controlling the pumping rate, which is obtained by subtracting the flow rate corresponding to volume recovery of the hydraulic fluid due to the relief of compression of the hydraulic fluid therefrom, to control the ram in the later state.