Tooling and method for producing compacts in powder metallurgy

摘要

1,127,447. Compacting metal powders; hollow compacts. RALEIGH INDUSTRIES Ltd. 1 March, 1967 [15 Dec., 1965], No. 53341/65. Heading B5A. Tooling for producing hollow compacts of metal powder comprises a core rod movable along its axis which forms a core in powder placed in the die, and a second rod, movable along the same axis as the first rod, which enters the powder in contact with the first rod. Both rods may be tapered. As shown, a bottom punch 1 supported on a fixed platform 2 extends into a die 3. Bottom core rod 4 extends up through punch 1 and die 3, its top 5 being level with the top 6 of die 3. It is supported by a piston 8 in cylinder 7 operated by compressed air or hydraulic fluid, the position of the top of the core rod 4 being adjustable via by screw collar 14. The upper core rod 16 comprises a straight portion 17 of equal radius to core rod 4 and a tapered portion 18 mounted in the top punch 16. In operation, the mould cavity is filled with powder 10 and the top 6 of die 3 is scraped clear of powder. Top punch 15 is then pressed downward and core rod 16 is pressed down into the powder until the base of the taper 18 is level with the top of bottom punch 1, lower core rod 4 having moved down against the pressure of the fluid in the cylinder, die 3 also moving downwards during the compression. Top punch 15 is then withdrawn and die 3 lowered further, the compact being left on top of the punch 1. The lower core rod may also be supported by a spring and the invention may be used for other pressing techniques, e.g. those operating with a floating or fixed die, or those in which both punches move to effect a double pressing.