Abstract: The geometry of the cast part is provided as a digital pattern and an inverse pattern for the lost casting mold including any core is generated from the digital pattern. A layer of a particulate molding material is provided. The molding material is made of a first material and a second material. The first material is chemically inert when irradiated by electromagnetic radiation. The second material is curable by a chemical curing process that is initiated by electromagnetic radiation. The layer is scanned by irradiating electromagnetic radiation on places of the layer corresponding to the inverse pattern for the lost casting mold including any core. The irradiation is controlled to initiate the chemical curing process in the second material.

Abstract: A method of producing an object by successive solidification of layers of a powder material is disclosed. The method provides a preformed base plate having a metal plate with a solidified layer of a powder material formed thereon. Then, successive layers of said powder material are applied and solidified on the solidified layer of the base plate to form the object. In further detail, the method for produces a three-dimensional by providing a support and a preformed base plate having an upper surface for supporting the object. The base plate is removably attached to the support. Means are provided for adjusting the elevation of said upper surface. A layer of the powder material is applied to the upper surface of the base plate. The powder material is solidified at points corresponding to a cross-section of the object by irradiation with electromagnetic or particle radiation. Then, the applying and solidifying steps are repeated for completing the object.

Abstract: An apparatus for producing a three-dimensional object by successive solidification of layers of a solidifiable material (7) at places corresponding to the respective cross-section of the object by means of radiation is provided whereby the apparatus comprises a support (4) for supporting the object (6) to be formed, a coating device (12) for applying layers of the solidifiable material (7) onto the support (4) or a previously solidified layer, a solidifying device (14) for solidifying the layers of the material (7) at places corresponding to the respective cross-section of the object and a heating apparatus (8) disposed above the support (4) in operational position for heating the solidifiable material (7), the heating apparatus (8) comprising at least one straight radiant heater (81) with a varying heating power along its length.

Abstract: In order to achieve a homogeneous density distribution in a layer to be solidified of a three-dimensional object produced by laser sintering a laser beam is passed across the surface of the layer to be solidified, whereby the travelling speed of the beam varies as a function of the length of lines of a line pattern.

Abstract: An apparatus for layerwise production of an object using laser sintering by solidifying a material which is solidifiable by electromagnetic radiation comprises a device (5) for producing an electromagnetic beam (6) and a focusing device (8) for focusing the beam (6) onto the material within a working plane (7), whereby the focusing device (8) comprises a lens (9) and a mount (10) holding the lens (9), a ring nozzle (12) arranged adjacent to the image-side surface (11) of the lens (9) facing the working plane (7), the ring nozzle having its outlet oriented relative to the image-side surface (11) so that a discharged stream strokes tangentially along the image-side surface (11) towards the center, the inlet of the ring nozzle being selectively connected with a source of pressurized gas.

Abstract: In a method for calibrating the deflection control of a laser beam a light-sensitive medium (5) is exposed to a laser beam (2) at predetermined positions for generating a test pattern (20), thereafter digitized partial pictures of pattern portions (21) of the test pattern (20) are produced and the digitized partial pictures are composed to a digitized overall picture of the test pattern (20). The correction data for the control (4) for deflecting the laser beam (2) are calculated on the basis of a comparison of actual positions of the laser beam (2) on the digitized overall picture with predetermined desired coordinates.

Abstract: An apparatus for producing a three-dimensional object by successive solidification of layers of a powder material at points corresponding to a cross-section of said object using electromagnetic or particle radiation comprises support means having an upper side for supporting the object thereon at a determined elevation, elevation adjustment means for varying the elevation, means for applying a layer of the material onto the upper side or onto another layer formed on the upper side, and irradiation means for irradiating the layer of the material at the points corresponding to a cross-section of the object. For reducing the production time of the object the apparatus further comprises a prefabricated base plate on the upper side, the base plate being made of a material which the powder material adheres to when being solidified, and means for removably connecting the base plate to the upper side of the support means.

Abstract: In an apparatus for producing a three-dimensional object by laser sintering the object is produced by successive solidification of layers of a powder material at points corresponding to a cross-section of said object using radiation for solidifying said powder material. The apparatus includes a support having a substantially plane upper side for supporting the object, a material applying device for applying a layer of the material onto the upper side or onto another layer formed on the upper side, and a solidification device for solidifying a layer of the material by irradiation. The material applying device has a coating device and a drive for displacing the coating device in a direction parallel to the upper side of the support.