Pulsed pressurized powder feed system and method for uniform particulate material delivery

A pressurized powder delivery system for delivering a quantity by weight of particulate material to a die cavity of a powder press, said delivery system comprising:

• a hopper receptive of a quantity of particulate material, said hopper having a discharge opening at the lower end thereof, a valve associated with the discharge opening, said valve having an open position and a closed position;
• a scale vessel for receiving a quantity of particulate material from said lower end of said hopper when said valve is in said open position, said scale vessel having at least one egress opening for releasing the particulate material therein, said scale vessel having an upper edge with at least two support points situated thereon, an elongated support beam suspended from and attached at its proximal end to each of said at least two support points and attached at its distal end to a crossbar;
• a pressure vessel having a sealable top opening situated directly under said bottom egress opening for receiving the particulate material from said bottom egress opening and a bottom opening sealingly connected to a feed conduit, the feed conduit sealingly connected to and openly communicating with the interior of a delivery receptacle for delivering powder thereto;
• a pressure generator sealingly attached to said pressure vessel for providing supra atmospheric pressure to the interior of said die cavity when said die cavity;
• an exhaust portal for releasing said supra atmospheric pressure from within said die cavity;
• a load cell upon which said crossbar rests, said load cell having a signal sender for sending signals to a controller for opening and closing said valve associated with said discharge opening of the hopper.

A method for delivering a quantity of particulate material to a die cavity of a powder press so that said particulate material is uniformly dense throughout said die cavity, said method comprising the steps of:

• generating supra-atmospheric pressure behind the particulate material,
• using the supra-atmospheric pressure to push the particulate material through a feeding receptacle having an egress that registers with and opens into said die cavity, into said die cavity;
• and
• fluidizing the particulate material within said die cavity to evenly distribute the particulate material so that it is substantially uniform in density throughout the die cavity.

A method for delivering a constant weight of particulate material uniformly into a die cavity comprising the steps of:

• providing a quantity of particulate material,
• allowing said particulate material to flow at a first rate into a weighing receptacle resting on a scale for registering the weight of the particulate material;
• reducing said flow to a second rate when the scale registers a weight that is from about one quarter to about three quarters that of the predetermined weight;
• stopping said flow when the scale registers the constant weight;
• and
• generating pressure within the pressure vessel to push the constant weight of particulate material into the die cavity through a feeding receptacle that registers with the die cavity.

A method for producing a part having a complex shape and tight dimensional tolerances by powder metallurgy comprising:

• providing a die cavity having a shape corresponding to that of the part;
• generating pressure from behind a powder feeding receptacle that registers with the die cavity to push the particulate material through the receptacle into the die cavity;
• fluidizing the particulate material within the die cavity to evenly distribute the particulate material to a uniform density throughout the die cavity;
• and
• compressing said particulate material within said die cavity to cause said particulate material to bond together thereby producing said part.