Abstract:
A method of obtaining a sample of materials includes building a product through an additive manufacturing process. A capsule is formed with an internal chamber inside of the capsule. The capsule is formed during the building of the additive manufacturing product. A sample of powder is encapsulated inside the internal chamber as the capsule is built. The internal chamber is hermetically sealed from an exterior environment to retain the sample of powder in the internal chamber.

Description:
BACKGROUND 
     This invention relates generally to the field of additive manufacturing. In particular, the present invention relates to the feed material used to create additively manufactured articles. 
     Additive manufacturing is an established but growing technology. In its broadest definition, additive manufacturing is any layerwise construction of articles from thin layers of feed material. Additive manufacturing may involve applying liquid, layer or powder material to a workstage, then sintering, curing, melting, and/or cutting to create a layer. The process is repeated up to several thousand times to construct the desired finished component or article. 
     Various types of additive manufacturing are known. Examples include stereolithography (additively manufacturing objects from layers of a cured photosensitive liquid), Electron Beam Melting (using a pulverant material as feedstock and selectively melting the pulverant material using an electron beam), Laser Additive Manufacturing (using a pulverant material as a feedstock and selectively melting the pulverant material using a laser), and Laser Object Manufacturing (applying thin, solid sheets of material over a workstage and using a laser to cut away unwanted portions). Each method has advantages and disadvantages. For example, one disadvantage of Laser Additive Manufacturing is that as pulverant material is made from increasingly fine particles as required for ever-thinner layers, the pulverant material may begin to clump, and the increased surface area to volume ratio of finer particles results in higher oxidation rates. 
     Non-additively manufactured production parts can be traced to an original forged billet, a pour of metal at a foundry, or to the original sheet metal. It is not as easy to trace the pedigree of parts built by additive manufacturing. Economically it is unlikely that production parts will be built of a virgin material. Building five pounds of product may require one hundred pounds of powdered starting material. It is likely that the product will be built from a mixture of virgin material, previously used, recycled, or reprocessed metal powder. Powdered metals are prone to contamination through oxidation, humidity, and any remnants of a previous build. This creates a problem of documenting the condition/properties of the powdered metal used to build the end material. 
     SUMMARY 
     A method of obtaining a sample of materials includes building a product through an additive manufacturing process. A capsule is formed with an internal chamber inside of the capsule. The capsule is formed during the building of the additive manufacturing product. A sample of powder is encapsulated inside the internal chamber as the capsule is built. The internal chamber is hermetically sealed from an exterior environment to retain the sample of powder in the internal chamber. 
     An additional embodiment of the present invention includes a method of obtaining a sample of materials. The method includes building a product through an additive manufacturing process. A capsule is formed with an internal chamber inside of the capsule. The capsule is formed during the building of the additive manufacturing product. A sample of powder is encapsulated inside the internal chamber as the capsule is built. The internal chamber is hermetically sealed from an exterior environment to retain the sample of powder in the internal chamber. The capsule is removed from the additive engineering process after the additive manufacturing product is built. The capsule is then severed along a groove in the capsule by applying torsional stress to flanges at the distal ends of the capsule. 
     An additional embodiment of the present invention includes a method of obtaining a sample of materials. The method includes building a product and a capsule through an additive manufacturing process. A capsule is formed with an internal chamber inside of the capsule. A sample of powder is encapsulated inside the internal chamber as the capsule is built. Identification information of the product is provided on the capsule by the additive manufacturing process. The internal chamber is hermetically sealed from an exterior environment to retain the sample of powder in the internal chamber. The capsule is removed from the additive engineering process after the product is built. The capsule is then severed, the sample of powder is analyzed, and the analysis is used to categorize the product. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic, cross-sectional view of an exemplary embodiment of a capsule in accordance with the present invention. 
         FIG. 2  is a schematic, perspective view of an exemplary embodiment of a capsule in accordance with the present invention. 
         FIG. 3  is a schematic block diagram of a method incorporating the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a schematic, cross-sectional view of an exemplary embodiment of capsule  10  in accordance with the present invention. Capsule  10  includes internal chamber  12 . First flange  14  is located at a first distal end of capsule  10 . Second flange  16  is located at a second distal end of capsule  10 . Groove  18  is located between first flange  14  and second flange  16  on an exterior surface of capsule  10 . Groove  18  extends circumferentially around an exterior surface of capsule  10 . Sample powder  20  is encapsulated within internal chamber  12  of capsule  10 . 
     During an additive manufacturing process, capsule  10  is built concurrently with the formation of an additive manufacturing product. As the additive manufacturing product is built, capsule  10  is also built. During the formation of capsule  10 , sample powder  20  is placed in internal chamber  12  of capsule  10 . The encapsulation of sample powder  20  during the additive manufacturing process enables collection of the same powder used to build the additive manufacturing product. 
     A benefit of forming capsule  10  of sample powder  20  during the additive manufacturing process alongside the additive manufacturing product is that capsule  10  would be built, filled, and sealed during the build of the additive manufacturing product completely untouched by human hands. This method allows for minimal contamination of sample powder  20  throughout the additive manufacturing process which prevents problems associated with oxidation and humidity. 
       FIG. 2  shows a schematic, perspective view of an exemplary embodiment of capsule  10  in accordance with the present invention. First flange  14  is located at a first distal end of capsule  10 . Second flange  16  is located at a second distal end of capsule  10 . Groove  18  is located between first flange  14  and second flange  16  on an exterior surface of capsule  10 . Groove  18  extends circumferentially around an exterior surface of capsule  10 . Identification information  22  is written onto capsule  10  during the additive manufacturing process. In this embodiment, identification information is provided on second flange  16 , but can be provided anywhere on an exterior of capsule  10 . 
     After the additive manufacturing product and capsule  10  of sample powder  20  are built, sample powder  20  can be retrieved at a later stage and analyzed to document the conditions and properties of sample powder  20 . The results of analyzing the conditions and properties of sample powder  20  can then be used to classify and categorize the build conditions of the corresponding additive manufacturing product built along with sample powder  20 . Sample powder  20  is retrieved from capsule  10  after severing capsule  10  by applying torsional stress to first flange  14  and second flange  16 . The torsional stress causes capsule  10  to sever along groove  18  and dissects capsule  10  into two halves. Once capsule  10  has been severed, sample powder  20  is retrieved from capsule  10  to be analyzed. As opposed to traditional cutting methods involving the use of a cutting tool, severing capsule  10  with torsional stress prevents contamination of sample powder  20  that occurs when using a cutting tool. 
     Additionally, flanges  14  and  16  can be sectioned, polished, etched and used for metallography for evaluation of grain size, contamination, hardness, or other solid material characteristics. 
     Adding identification information  22  during the additive manufacturing process also decreases the risk of contamination of sample power  20 . Identification information  22  is placed on capsule  10  during the additive manufacturing process instead of adding identification information  22  to capsule  10  after the build under conditions different from the controlled conditions used during the additive manufacturing process. 
       FIG. 3  shows a schematic block diagram of method  24  of obtaining a sample of materials incorporating the present invention. Method  24  includes building a product by additive manufacturing (step  26 ), forming capsule  10  while building the product (step  28 ), encapsulating powder sample  20  from the product build in capsule  10  (step  30 ), forming identification information  22  on capsule  10  (step  32 ), removing capsule  10  from the additive manufacturing process (step  34 ), severing capsule  10  by applying torsional stress to first flange  14  and second flange  16  of capsule  10  (step  36 ), analyzing powder sample  20  (step  38 ), and categorizing the additive manufacturing product based on the analysis of powder sample  20  (step  40 ). 
     Building a product by additive manufacturing (step  26 ) includes producing a product by any additive manufacturing process that uses pulverant material for the base material. For example, Selective Laser Sintering or melting and selective Electron Beam Melting processes use pulverant granules to create an additively manufactured part. Forming capsule  10  while building the product (step  28 ) includes building capsule  10  at the same time as the additive manufacturing product is built. Encapsulating powder sample  20  from the product build in capsule  10  (step  30 ) includes forming capsule  10  to enclose powder sample  20  within capsule  10 . Forming identification information  22  on capsule  10  (step  32 ) includes using the additive manufacturing process to produce identifying information  22  on capsule  10 . During the additive manufacturing process, various language characters are created by the additive manufacturing process to form identification information  22  on capsule  10 . Removing capsule  10  from the additive manufacturing process (step  34 ) includes removing capsule  10  from the additive manufacturing building stage once the additive manufacturing process is complete. Severing capsule  10  by applying torsional stress to first flange  14  and second flange  16  of capsule  10  (step  36 ) includes twisting first flange  14  and second flange  16  of capsule  10  in opposite directions until capsule  10  severs along groove  18 . After capsule  10  is severed, powder sample  20  can then be analyzed. Analyzing powder sample  20  (step  38 ) includes extracting powder sample  20  from the severed halves of capsule  10 , and testing powder sample  20  for various characteristics including but not limited to flowability, particle size distribution, or high cycle fatigue test. Categorizing the additive manufacturing product based on the analysis of powder sample  20  (step  40 ) includes using the results of sample powder  20  analysis to classify and characterize the product from the corresponding additive manufacturing process. 
     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.