Patent ID: 6403025
Filing Date: 2002-06-11
Classification: B22F,B30B

Abstract:
A method for producing a rotational symmetrical powder metal body comprising:a) introducing a predetermined volume of powder material into a compacting chamber provided in a hollow die comprising at least one die plate having a central opening, which has substantially the cross sectional shape of the body to be produced, b) compacting the material in mainly an axial direction in the compacting chamber with a first punch, by urging said first punch axially into said compacting chamber, c) advancing said first punch further into said compacting chamber, thereby further compacting the powder material, d) imparting upon the at least one die plate a biasing tension, causing an edge portion encircling the opening in the at least one die plate to move slightly under increasing tension in the direction of the advance movement of the first punch, thereby causing radial reduction of the size of the opening, e) causing axial compression also in a direction opposed to that caused by the said first punch by means of a second punch, arranged to move relative the die in a direction opposed to that of the advance movement of the first punch, and f) retracting the first punch axially, and relieving the biasing tension from the at least one die plate thereby regaining its initial form and simultaneously expelling the compacted material.