Patent ID: 6101858
Filing Date: 2000-08-15
Classification: B21C

Abstract:
A method for forming artistic forked pipes made of aluminum or copper alloy, said method includes the steps of:(A) selecting an extruded aluminum or copper alloy blank, said extruded blank is provided with a central hole, a plurality of through holes. and a plurality of protruding columns; said through holes are formed surrounding said central hole, said protruding columns are formed on an outer wall of said extruded material, said protruding columns are positioned to lie between said through holes;(B) milling said extruded blank with a mechanical milling process to form a workpiece having a main pipe and a plurality of branch pipes, said main pipe and each of said branch pipes are in communication with each other, said main pipe is processed to form a straight main pipe hole, said branch pipes are milled so as to form a straddling portion with an arc, the material of said protruding columns on said extruded blank are milled to form protruding portions at the two lateral sides of said main pipe, and to form protruding portions at the two lateral sides of said straddling portion;(C) enlarging the bore of said main pipe by using a first die core with a shape corresponding to that of said main pipe, said first die core is fitted in a main pipe hole of said extruded pipe, a forming die is provided for said protruding portions of said main pipe, and an elastic protecting die is provided for elongated ends of a wall of said extruded pipe, said forming die exerts pressure onto said protruding portions of said main pipe, the material of said protruding portions are gradually and uniformly extruded toward said elongated ends of said wall of the extruded pipe, then said main pipe is formed to gradually form an enlarged main pipe hole;(D) forming forked branch pipes by using a second die core with a shape corresponding to that of said branch pipes, said second die core is provided in said branch pipe holes of said extruded pipe, and a middle die core is fitted in said central hole of said straddling portion, a forming die is provided for said protruding portions of said branch pipes, and an elastic protecting die is provided for elongated ends of walls of said branch pipes; said forming die exerts pressure onto said protruding portions of said branch pipes, the material of said protruding portions are gradually and uniformly extruded toward said elongated ends of said walls of said branch pipes, said branch pipes are gradually formed with a straddling portion on a forked portion including said branch pipes, a forming pressing die is used to process said straddling portion by forming so that the material on a wall of said straddling portion forms a recessed portion to thereby complete the operation of forming said forked branch pipes.