Abstract: Powder spreaders suitable for use with layered manufacturing processes are disclosed in which a strip of flexible material of a width which spans the powder bed is used to spread, level, and, optionally, compact deposited powder to form a layer of the powder bed. The strip surface moves relative to the deposited powder it is spreading as the working portion of the strip, i.e., the portion of the strip that is in contact with the powder, traverses across the powder bed so that it can provide lift to the powder in front of it and, optionally, compaction to the powder below it. The working portion of the strip can be configured to have its leading and trailing surface contours to be different from one another, and, optionally, to have these contours and its bottom edge contour be independently adjustable. Layered manufacturing systems comprising such powder spreaders are also disclosed.

Abstract: Laser drilling devices are disclosed which include a laser beam source and a laser drilling head. The laser drilling head includes a beam manipulator system in which the only dynamically moving optical element is a mirror. The mirror is dynamically and reciprocally translatable along the direction of the incoming laser beam and is also dynamically and reciprocally tiltable about an axis that is perpendicular to the nominal optical axis of the drilling head. The drilling head also includes a spinnable laser beam rotating system, a simplified compensation system, and a focusing system. The compensation system includes as its only laser beam path shifting optical elements on or two wedge plates which, if two, are fixably rotatable relative to one another in planes which are perpendicular to the nominal optical axis of the laser drilling device.

Abstract: Powder spreaders suitable for use with layered manufacturing processes are disclosed in which a strip of flexible material of a width which spans the powder bed is used to spread, level, and, optionally, compact deposited powder to form a layer of the powder bed. The strip surface moves relative to the deposited powder it is spreading as the working portion of the strip, i.e., the portion of the strip that is in contact with the powder, traverses across the powder bed so that it can provide lift to the powder in front of it and, optionally, compaction to the powder below it. The working portion of the strip can be configured to have its leading and trailing surface contours to be different from one another, and, optionally, to have these contours and its bottom edge contour be independently adjustable. Layered manufacturing systems comprising such powder spreaders are also disclosed.

Abstract: A removable build box for a three dimensional printer comprises a build box tray defining a build chamber for part assembly and a material feed chamber for supplying powder material to the build chamber. The build and feed chambers have lower piston stops. A build chamber piston engages with the build chamber and with the build chamber piston stops at a lowermost position. A feed chamber piston engages with the feed chamber and with the feed chamber piston stops at a lowermost position. A quick connection coupling is between the build chamber piston and a build chamber z-axis actuator configured to move the build chamber piston when connected thereto. A quick connection coupling is between the feed chamber piston and a feed chamber z-axis actuator configured to move the feed chamber piston when connected thereto. The build box tray may be easily removed from the three dimensional printer.

Abstract: Methods for sintering aluminum powder comprise providing aluminum powder and heating the aluminum powder in a nitrogen atmosphere containing a partial pressure of water vapor in the range of about 0.001 kPa to about 0.020 kPa to sinter the aluminum powder to a transverse rupture strength of at least about 13.8 MPa. The aluminum powder is not pressed together by a mechanical force that substantially deforms particles of said aluminum powder either prior to or during the step of heating. Articles comprising sintered aluminum powder. The sintered aluminum powder has a transverse rupture strength of at least about 13.8 MPa. The microstructure of the sintered aluminum powder contains no compositional concentration gradients indicative of the use of a sintering aid and no evidence of particle deformation having occurred by an application of a mechanical force prior to or during the sintering of the aluminum powder.

Abstract: A method for producing a cast article comprises using a porous powder article as a sacrificial pattern. The porous powder article is preferably made using a rapid prototyping process. The porous powder article is used as a sacrificial pattern for a mold into which a molten metal is cast. Some embodiments include a step of proving the porous powder article with a ceramic coating. Methods of making molds and patterns using a porous powder article are also disclosed. The powder comprising the porous powder article may be a metal, ceramic or cermet. In some embodiments, the powder alloys with the molten casting metal. In some other embodiments, the powder and the casting metal form a composite. Sacrificial casting mold patterns comprising porous powder articles and casting molds comprising such sacrificial patterns are also disclosed.

Abstract: Gas permeable molds and mold segments having open porosity (60) are disclosed. Blind vents (56) in the mold wall's (54) outside surface (52) allow for an uninterrupted molding surface (62) while enhancing the gas permeability provided by the open porosity (60). Methods of making such gas permeable molds include forming them from sintered material. Methods also include the use of solid free-form fabrication followed by sintering. Also disclosed are unitary structures (150), for use in EPS bead molding, having a steam chest portion (152) with gas impermeable walls (156) and a mold section (154) having a gas permeable mold wall (172) having open porosity (176), and, optionally, open and/or blind vents (180, 178). Methods for making such unitary structures (150) include the use of solid free-form fabrication.

Abstract: A green article comprising an A-B powder mixture and methods of manufacturing such green articles and corresponding sintered articles are disclosed. The A-B powder mixture consists of a minor volume fraction of a relatively fine powder A and a complementary major volume fraction of a relatively coarse prealloyed powder B wherein the A-B powder mean particle size ratio is at least about 1:5. Metal powder A consists of one or more elemental metals or alloys which has a melting or solidus temperature above the highest sintering temperature at which the A-B powder mixture may be sintered without slumping. Prealloyed metal powder B consists of one or more alloys which are amenable to supersolidus liquid phase sintering. Green articles made from the A-B powder have a wider sintering temperature window than do articles made from prealloyed metal powder B alone.