Patent Application
20160068282
This invention relates generally to the field of manufacturing. In particular, the present invention relates to the preparation of metallic alloy powder used to create either hot isostatically pressed or extruded metallic alloy logs that are subsequently converted through additional thermomechanical processing and machining into aerospace products, but this invention is also applicable to any product that employ powder constituents as raw material anywhere during its manufacturing process (for example pharmaceuticals, pigment, electronics, catalysts, and others).
In preparation for manufacturing, a powder, composed of the particles of a given and rather broad distribution, is introduced through an opening at the top of a can. It falls through an atmosphere in the can, and as it free falls it creates a pyramid shaped cone at the bottom of the can. During the free-fall the powder particles segregate due to the size differentiation (as defined by kinetics-of-flow). The segregation further progresses during the formation of the cone, the coarse particles may be free-flowing while the finer particles can be cohesive with a tendency to accumulate in the center of the cone. In addition, very fine particles are suspended in the can atmosphere and due to the electrostatic attraction to the can walls will with time adhere to the can walls. However, the very fine particles may detach from the walls and fall to the bottom of the can in clumps to further segregate the powder in the cone.
This segregation leads to non-homogeneity in a final manufacturing product due to the variability in microstructure and properties of the powder. This non-homogeneity may ultimately result in a final manufacturing product not matching the desired specification. Non-homogeneity of final product is typically undesirable in the final product of metallic alloy powders.
A powder filling method includes introducing a tube into a can so that the lower end of the tube is near the bottom of the can. The powder in the can is introduced through the tube. The proximity of the lower end of the tube to the powder is controlled by retracting the tube as the powder fills the can.
A powder filling method includes introducing a tube into a can. The powder is supplied through the tube to fill the can. The tube is retracted as the powder fills the can to maintain a consistent distance between the lower end of the tube and the powder. The powder in the can is agitated through rotary agitation.
As the level of powder 12 rises, tube 18 is retracted from can 10 to maintain common distance 19 between tube 18 and powder 12. Tube 18 will minimize the accumulation of fine powder particles 16 at the walls of can 10. Introduction of powder 20 into can 10 through tube 18 in close proximity to bottom of can 10 minimizes interparticle motion, eliminates cone formation of powder 20, and eliminates the suspension and plating of fine powder particles 16 on the interior surfaces of can 10. Eliminating the formation of cone 14 and the plating of fine powder particles 16 on the interior surfaces of can 10 minimizes segregation of powder 12. The decrease in segregation of powder 12 results in an increased homogeneity of powder 12 used in a process. The homogeneity of powder 12 ultimately provides a more uniform grain growth and provides more consistent mechanical properties of end product.
Additionally, during the filling process of can 10, can 10 is periodically vibrated in order to increase the tap density of powder 12. Tap density of powder 12 includes a volume specific weight powder 12 has after it has been settled or packed. Increased tap density of powder 12 helps to provide more consistent mechanical properties of the end product by reducing the flow inconsistencies of powder 12 with a lower tap density.
Small fan blades 26 provide a mechanical agitation of free-falling powder 20 to create powder dispersion 28. Small fan blades 26 are sized so that the outer diameter of small fan blades 26 is less than the inner diameter of tube 18. Small fan blades 26 are sized smaller than the inner diameter of tube 18 so that fan 22 can be retracted through tube 18 and out of can 10. Retraction of fan 22 out of can 10 facilitates preparation for the next step in a process once the can filling process of can 10 is complete. During the filling of can 10, tube 18 is retracted from can 10 to maintain common distance 19 between tube 18 and powder 12. The retraction of tube 18 and fan 22 is designated by arrow 15 in
While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
The following are non-exclusive descriptions of possible embodiments of the present invention.
A powder filling method includes a tube is introduced into a can so that the lower end of the tube is near the bottom of the can. A powder is introduced into the can through the tube. The proximity of the lower end of the tube to the powder in the can is controlled by retracting the tube as powder fills the can.
The powder filling method of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, and/or additional components:
the powder filling method further includes agitating the powder in the can by rotary agitation;
the rotary agitation is performed by a fan located near the lower end of the tube;
the fan comprises a same composition as the powder;
the fan is driven by a fan shaft that extends through the tube;
the tube is retracted at a rate that maintains a consistent distance between a lower end of the tube and the powder;
the tube is retracted either mechanically, pneumatically, or hydraulically;
the fan is retracted at a rate equal to the tube;
the powder filling method further includes a vacuum present in the can;
the powder filling method further includes an inert atmosphere present in the can;
the can is periodically vibrated during the powder filling of the can; and
the powder comprises a metallic powder.
A powder filling method includes a tube introduced into a can. A powder is supplied through the tube to fill the can. The tube is retracted as the powder fills the can to maintain a consistent distance between a lower end of the tube and the powder. The powder is agitated in the can by rotary agitation.
The powder filling method of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, and/or additional components:
the powder filling method further includes the rotary agitation performed by a fan;
the fan comprises a same composition as the powder;
the powder is agitated as it exits the tube;
the fan is driven by a shaft that extends through the tube;
the fan is retracted at a rate equal to the tube;
the tube is retracted either mechanically, pneumatically, or hydraulically;
the powder filling method further includes a vacuum present in the can;
the powder filling method further includes an inert atmosphere present in the can; and
the can is periodically vibrated during the powder filling of the can.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2014/033723 | 4/11/2014 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61815358 | Apr 2013 | US |
