3d Systems, Inc.

The University of Queensland

Kenneth J Newell

Kris A Schmidt

John S Stockwell

Stephen Ruatta

Timothy Barry Sercombe

Charles H Zenuk

Charles W Hull

Khalil M Moussa

Michael Thomas Sherwood

Graham Barry Schaffer

Catherine Hinczewski

Brad Geving

Graham Barry Shaffer

A method for removing supports from a three-dimensional objected formed by selective deposition modeling. The three-dimensional object is formed from a curable phase change material and the supports are formed from a non-curable phase change material. The curable phase change material contains between about 5% to about 25% of a non-reactive wax in order to achieve the desired phase change characteristics of the material. When removing the supports with heat, discoloration undesirably occurs in the three-dimensional object as the non-reactive wax migrates within the object. The method prevents wax migration by cooling the object slowly past the freezing point of the build material such that a temperature differential no greater than about 5&#xb0; C. is present within the object. With the preferred build material having a freezing point of about 49.5&#xb0; C., this is achieved by lowering the temperature between about 62&#xb0; C. to about 52&#xb0; C. over a period of between about 5 to about 10 minutes so that the temperature of the regions of the object remain substantially equal as the freezing point is crossed during cooling.

Post processing three-dimensional objects formed by selective deposition modeling

A method for the manufacture of a three-dimensional object includes the steps of forming a mixture that contains a binder and a least one of aluminum or a first aluminum-base alloy into a green composite, removing the binder from said green composite, forming a porous perform structure, reacting the aluminum or first aluminum base alloy with nitrogen to form a rigid and continuous skeleton and infiltrating the porous structure with molten aluminum or second aluminum base alloy to form the three-dimensional object with near theoretical density. The green composite may be formed by an additive process such as computer aided rapid prototyping, for example, selective laser sintering. The method facilitates the rapid manufacture of aluminum components by an inexpensive technique that provides high dimensional stability and high density.

Infiltrated aluminum preforms

A method for the manufacture of a three-dimensional object includes the steps of forming a mixture that contains a binder and a least one of aluminum or a first aluminum-base alloy into a green composite, removing the binder from said green composite, forming a porous preform structure, reacting the aluminum or first aluminum base alloy with nitrogen to form a rigid skeleton and infiltrating the porous structure with molten aluminum or second aluminum base alloy to form the three-dimensional object with near theoretical density. The green composite may be formed by an additive process such as computer aided rapid prototyping, for example selective laser sintering. The method facilitates the rapid manufacture of aluminum components by an inexpensive technique that provides high dimensional stability and high density.

A method for removing supports from a three-dimensional object formed by solid freeform fabrication. The three-dimensional object and support structure both contain a phase change component in order to achieve the desired phase change characteristics needed for dispensing the material. The method prevents the phase change material within the three-dimensional object from migrating within the object during post processing to remove the support structure.

Post processing three-dimensional objects formed by solid freeform fabrication

A method for the manufacture of a three-dimensional object includes the steps of forming a mixture that contains a binder, a wetting agent, and a least one of aluminum or a first aluminum-base alloy into a green composite, removing the binder from said green composite forming a porous preform structure and infiltrating the porous preform structure with a molten second aluminum base alloy to form the three-dimensional object with near theoretical density. The wetting agent assists in wetting during infiltration. The green composite may be formed by an additive process such as computer aided rapid prototyping, for example selective laser sintering. The method facilitates the rapid manufacture of aluminum components by an inexpensive technique that provides high dimensional stability and high density.

Wetting agent for infiltrated aluminum preforms

A powder blend for use in laser sintering and a method for forming tough, strong, wear-resistant, corrosion-resistant infiltrated metal products are provided. The powder blend comprises a steel alloy, a polymeric binder and a high melting temperature fine particulate which are blended together, then applied layer by layer to a working surface in a laser sintering system, exposed a layer at a time to fuse together the powder until a green part of high strength is formed, and then the green part is infiltrated with a metal infiltrant in a non-reducing gas atmosphere at an effective temperature for an effective period of time. The preferred steel is a mild steel alloy.

Metal powder composition for laser sintering

A method for removing supports from a three-dimensional objected formed by selective deposition modeling. The three-dimensional object is formed from a curable phase change material and the supports are formed from a non-curable phase change material. The curable phase change material contains between about 5% to about 25% of a non-reactive wax in order to achieve the desired phase change characteristics of the material. When removing the supports with heat, discoloration undesirably occurs in the three-dimensional object as the non-reactive wax migrates within the object. The method prevents wax migration by cooling the object slowly past the freezing point of the build material such that a temperature differential no greater than about 5&deg; C. is present within the object. With the preferred build material having a freezing point of about 49.5&deg; C., this is achieved by lowering the temperature between about 62&deg; C. to about 52&deg; C. over a period of between about 5 to about 10 minutes so that the temperature of the regions of the object remain substantially equal as the freezing point is crossed during cooling.

A method of applying highly viscous paste-like build materials in layers in a solid freeform fabrication apparatus to form three-dimensional objects. A viscosity modifier is first introduced into the build material to establish a low viscosity state and then the material is dispensed in layers on a working surface. The viscosity modifier is then removed from the build material preferably by evaporation, and the layer is selectively solidified to form the three-dimensional object. The method substantially eliminates the undesirable effects of induced shear stress imposed on lower layers when attempting to apply uniform layers of highly viscous materials in solid freeform fabrication techniques. The method allows for the use of highly viscous paste-like materials that can include upwards of 50% by weight of metallic, ceramic, mineral, or polymer powders. Preferably the binder is a photocurable resin or thermocurable material which is selectively solidified to form the three-dimensional objects.

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Valencia, CA, United States of America

Kenneth J Newell