3d Systems, Inc.

Xerox Corporation

Paul F Jacobs

Dennis R Smalley

Charles W Hull

Thomas A Almquist

Hop D Nguyen

Charles W Lewis

Borzo Modrek

Joseph W Allison

Adam L Cohen

Mark Anthony Lewis

Abraham Liran

Jan Richter

Stuart T Spence

Richard Noel Leyden

Kris A Schmidt

Wayne A Vinson

Craig M Childers

William D Green

Joel R Finkel

Kenneth I Gustafson

Thomas H Pang

John J Gigl

J Scot Thompson

Kerry J Allen

Chris Robert Manners

Jeffrey S Thayer

Thomas L Thourson

Robert C Speiser

Hop D Hguyen

John D Worden

Thomas A Whatley

Andrzej R Serkuczewski

An improved method for stereolithographically making an object by alternating the order in which similar sets of vectors are exposed over two or more layers. In another method, a pattern of tightly packed hexagonal tiles are drawn. Each tile is isolated from its neighboring tiles by specifying breaks of unexposed material between the tiles. Using an interrupted scan method, vectors are drawn with periodic breaks along their lengths. In another method, modulator and scanning techniques are used to reduce exposure problems associated with the acceleration and deceleration of the scanning system when jumping between vectors or changing scanning directions. In another method, a capability for automatically inserting vents an drains into a three-dimensional object representation is provided.

Method of making a three-dimensional object by stereolithography

Method of and apparatus for making a three-dimensional object by stereolithography

A method is disclosed for making a molded refractory article comprising the steps of providing a mold including a molding pattern, the mold and molding pattern defining a mold cavity; filling the mold cavity around the molding pattern with a mixture comprising refractory particles and a heat fugitive binder; inserting a plurality of elements of relatively high melting point material into the mixture to displace a portion of the mixture; curing the mixture; separating the mold and molding pattern from the cured mixture; and sintering the combination of the cured mixture and mixture displacing elements to provide a reinforced molded refractory article. The mixture displacing elements preferably comprise a plurality of parallel tool steel rods. Also disclosed is an apparatus for molding the aforedescribed reinforced refractory article.

Apparatus and methods for economically fabricating molded refractory

Improved apparatus and methods for forming a layer of material over a surface of a previously-formed cross-section of a three-dimensional object in anticipation of forming a next cross-section of the object out of the layer. A volume of material, including at least some excess material, is placed over the surface, and the excess material is swept off by placing the excess material in the predetermined path of a sweeping member, the path being substantially in a plane spaced from a working surface of material. The member may be directed to sweep the excess material away through a successive number of sweeps, which may vary for each cross-section, at least a velocity which may vary for each sweep. Additionally, the clearance between the member and the surface of the previous cross-section may vary for each sweep. A 'winged' member is also provided, comprising two legs extending from a base, and a 'Trident' embodiment is also provided, comprising three legs extending from a base.

Recoating stereolithographic layers

An improved method for stereolithographically making an object by alternating the order in which similar sets of vectors are exposed over two or more layers. In another method, a pattern of tightly packed hexagonal tiles are drawn. Each tile is isolated from its neighboring tiles by specifying breaks of unexposed material between the tiles. Using an interrupted scan method, vectors are drawn with periodic breaks along their lengths. In another method, modulator and scanning techniques are used to reduce exposure problems associated with the acceleration and deceleration of the scanning system when jumping between vectors or changing scanning directions.

Methods and apparatus for use in building three-dimensional objects on substantially a cross-sectional basis including methods and apparatus for forming successive layers using counter-rotating rollers, ink jet recoaters, spinning members which sling material, applicator bars that dispense material via a meniscus and/or independently dispensed streams, and also including methods and apparatus to determine a preferred region over which to form a layer and to check for building errors.

Rapid recoating of three-dimensional objects formed on a cross-sectional

Recoating of stereolithographic layers

Methods and apparatus for providing a vibrational enhancement to the recoating process in stereolithography are disclosed. The formation of a thin layer of building material over a previous layer of structure of a partially completed three-dimensional object, in preparation for formation of an additional layer of structure, is enhanced by the use of vibrational energy imparted to the building medium. In a first preferred apparatus, vibration is induced into the surface of the material by a plurality of vibrating needles that penetrate below the working surface to a sufficient depth to ensure adequate coupling but not deep enough to come into contact with the surface of the partially completed part. In a second preferred apparatus, vibration is coupled directly to the object support. The vibrational energy is then transmitted through the part to the surface of the building material. In a first preferred method the partially completed object is overcoated with material and vibration is used to reduce the coating thickness. In a second preferred method, the partially completed object is undercoated with material and vibration is used to increase the coating thickness.

Vibrationally enhanced stereolithographic recoating

Methods and apparatus for providing a vibrational enhancement to the recoating process in stereolithography are disclosed. The formation of a thin layer of building material over a previous layer of structure of a partially completed three-dimensional object, in preparation for formation of an additional layer of structure, is enhanced by the use of vibrational energy imparted to the building medium. In a first preferred apparatus, vibration is induced into the surface of the material by a plurality of vibrating needles that penetrate below the working surface to a sufficient depth to ensure adequate coupling but not deep enough to come into contact with the surface of the partially completed part. In a second preferred apparatus, vibration is coupled directly to the object support. The vibrational energy is then transmitted through the part to the surface of the building material. In a first preferred method the partially completed object is overcoated with material and vibration is used to reduce the coating thickness. In a second preferred method, the partially completed object is under-coated with material and vibration is used to increase the coating thickness.

Apparatus and method for stereolithographically forming a three-dimensional object includes a vessel for holding a building material and a smoothing member for forming a uniform coating over a previously formed layer of the object. The smoothing member has a plurality of blades. The smoothing member is swept over a previously formed layer of the object, in at least two directions. Different clearances between the lower surface of the smoothing member and the upper surface of the previously formed layer are used to provide a uniform coating for a subsequent layer over the previously formed layer. The sweeping velocity of the smoothing member can be varied. Retractable needles are attached to the smoothing member for adjusting a blade gap between a lower surface of the smoothing member and the surface of the building material.

The instant invention is directed to related methods of producing a three-dimensional object by dispensing sheets of a material, capable of physical transformation upon exposure to synergistic stimulation, onto a substantially flat working surface of a previous cross-section. In one preferred embodiment, sheets of a photoresist are employed which change solubility upon exposure to electromagnetic radiation. In other preferred embodiments, non-photoreactive sheets are employed, which ablate upon exposure to infrared radiation.

Method of building three dimensional objects with sheets

Method of and apparatus for measuring and controlling fluid level in

An improved method for stereolithographically forming a three-dimensional object wherein ordinarily solidified internal walls of the object remain at least partially unsolidified. Any unsolidified medium within the object can be drained from the internal walls of the object prior to post-curing so that a hollow three-dimensional object is formed. The object is formed on a layer by layer basis with the internal portion of each layer of the object formed as a grid of solidified portions and unsolidified portions wherein the solidified and unsolidified portions are different on each layer. Objects formed in this manner can be used as patterns in investment casting.

A method and apparatus for eliminating or substantially reducing curling effects in stereolithographically formed objects. Synergistic stimulation is applied to a curable material to form a three dimensional object through the build up of successive layers. Curling between successive layers is eliminated or substantially reduced by curing a balancing layer in relation to a balanced layer such that reverse curl of the balanced layer caused by the balancing layer offsets or negates normal curl of the balanced layer caused by the balancing layer.

Method and apparatus for stereolithographic curl balancing

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La Crescenta, CA, United States of America

Paul F Jacobs