Multiple Materials Systems For Selective Beam Sintering

Physical Sciences : Mechanical

Available for licensing

Inventors

  • Carl Deckard, Ph.D. , Mechanical Engineering
  • Joseph Beaman, Jr., Ph.D. , Mechanical Engineering
  • David Bourell, Ph.D. , Mechanical Engineering
  • Joel Barlow, Ph.D. , Chemical Engineering
  • Harris Marcus, Ph.D. , Mechanical Engineering
  • Neil Vail, Ph.D. , Chemical Engineering
  • Wendy Weiss, M.S. , Materials Science and Engineering
  • Udaykumar Lakshminarayan, Ph.D. , Center for Materials Science

Background/unmet need

Current selective beam sintering technology is limited to coarse sheared polymers, in which optimum sintering of metals and ceramics with maximized beam coupling and process flexibility is impossible. Through innovation and improved fabrication methods, selective laser sintering could be used commercially to fabricate metallic and ceramic objects. Due to the relatively high ratio of surface tension to viscosity of metals and ceramics compared to polymers (four orders of magnitude), metal and ceramic powders have a strong propensity to form spherical balls when irradiated. Thus, traditional selective beam sintering technology cannot be used to directly manufacture metal and ceramic parts.

In order to alleviate this problem and to ensure full density throughout the part, careful design of beam scan path, power, and scan spacing is required. In order to successfully produce metal and ceramic parts through selective beam sintering, the solid-liquid interface must be constantly maintained while previously-fabricated layers allow for new layers to nucleate by epitaxial solidification. Additionally, the application of pressure to a powder during sintering could potentially improve the strength of manufactured parts.

Invention Description

Researchers at The University of Texas at Austin have proposed a powder material approach by which structural parts may be fabricated through a particular method of selective beam sintering. Powder of one material is coated with a lower melting/dissociation temperature material. The powder mass is then processed using selective beam sintering. This step is analogous to liquid-phase sintering, in which the low-temperature phase(s) melt first and infiltrate the powder mass locally. Capillarity effects control beam interaction volume, while epitaxial growth of the coating material is limited by the low temperature phase(s). During secondary processing of the material, the low-temperature phase(s) can be diffused into high-temperature phase(s) or vaporized to produce a structure of high-temperature material.

Improved control of molten zones and epitaxial growth allows for the fabrication of metal and ceramic parts, as well as the application of other physical properties, such as electrical insulation. Overall, the proposed method for selective beam sintering allows for a greater range of possible products, which can vary by material or porous structure.

Another approach to improving the strength of sintered products is the use of an electrostatic field across a dielectric powder. The result is the application of external pressure that does not interfere with the laser radiation, but successfully levels the powder layers for enhanced sintering.

Benefits/Advantages

  • Materials may be blended in appropriate concentrations if powder coating is inconvenient
  • Multiple low-temperature phases may be used for powder coating
  • Utilizes capillarity effects to control beam interaction volume
  • Novel control over epitaxial growth, which is essential to sintering of different types of materials
  • Solves problems pertaining to porosity, shrinkage, available power density, and surface finish of sintered products
  • Allows for sintering of metals and ceramics while maximizing beam coupling and process flexibility
  • Eliminates the need for mechanical powder leveling

Features

  • Novel method for selective beam sintering that utilizes concept of liquid phase sintering
  • Process is specific to alloy development
  • Allows for greater range of fabricated products by selective beam sintering
  • Combinations of different materials can yield an infinite range of products
  • Control over molten zones and epitaxial growth allows for product customization
  • Process can be tailored to yield materials varying in porous strength
  • Pressure application through an electrostatic field across a dielectric powder

Market potential/applications

According to Markets and Markets Research, the global industrial 3D printing market is expected to reach $4.75 billion by 2022 while growing at a compound annual growth rate of 29.2%. The introduction of new materials that can be synthesized by selective beam sintering as well as other methods of 3D printing drives the market towards the need for innovation in fabrication methods. The proposed method for selective beam sintering allows for a greater range of products in terms of material type and unique characteristics. Aerospace, defense, automotive, and other industries can benefit greatly from implementing this novel approach to selective beam sintering for the efficient production of metal and ceramic parts.

Development Stage

Lab/bench prototype

IP Status

  • 5 foreign patents application filed
  • 12 foreign patents issued