ENHANCED BUILDING TECHNIQUES IN STEREOLITHOGRAPHY

    公开(公告)号:CA2186613A1

    公开(公告)日:1995-11-02

    申请号:CA2186613

    申请日:1995-04-25

    Applicant: 3D SYSTEMS INC

    Abstract: A method and apparatus for making high resolution objects by stereolithography utilizing low resolution materials which are limited by their inability to form unsupported structures of desired thinness and/or their inability to form coatings of desired thinness. Data manipulation techniques, based on layer comparisons, are used to control exposure in order to delay solidification of the material on at least portions of at least some cross-sections until higher layers of material are deposited so as to allow down-facing features of the object to be located at a depth in the building material which is equal to or exceeds a minimum cure depth that can effectively be used for solidifying these features. Similar data manipulations are used to ensure minimum reliable coating thicknesses exist, above previously solidified material, before attempting solidification of a next layer. In addition, horizontal comparison techniques are used to provide enhanced cross-sectional data for use in forming the object. Further, several techniques for automatically performing Zerror correction through the manipulation of a three-dimensional object representation are described. Still further, techniques for producing objects useful for investment casting applications are described, including techniques allowing for the drainage of unsolidified material. A method and apparatus for the automatic generation of vents and drain is also provided.

    ENHANCED BUILDING TECHNIQUES IN STEREOLITHOGRAPHY
    23.
    发明申请
    ENHANCED BUILDING TECHNIQUES IN STEREOLITHOGRAPHY 审中-公开
    强化建筑技术在立体图中的应用

    公开(公告)号:WO9529053A3

    公开(公告)日:1996-01-18

    申请号:PCT/US9505148

    申请日:1995-04-25

    Applicant: 3D SYSTEMS INC

    CPC classification number: G06T17/00 B29C64/135 B29C64/40

    Abstract: A method and apparatus for making high resolution objects by stereolithography utilizing low resolution materials which are limited by their inability to form unsupported structures of desired thinness and/or their inability to form coatings of desired thinness. Data manipulation techniques, based on layer comparisons, are used to control exposure in order to delay solidification of the material on at least portions of at least some cross-sections until higher layers of material are deposited so as to allow down-facing features of the object to be located at a depth in the building material which is equal to or exceeds a minimum cure depth that can effectively be used for solidifying these features. Similar data manipulations are used to ensure minimum reliable coating thicknesses exist, above previously solidified material, before attempting solidification of a next layer. In addition, horizontal comparison techniques are used to provide enhanced cross-sectional data for use in forming the object. Further, several techniques for automatically performing Z-error correction through the manipulation of a three-dimensional object representation are described. Still further, techniques for producing objects useful for investment casting applications are described, including techniques allowing for the drainage of unsolidified material. A method and apparatus for the automatic generation of vents and drain is also provided.

    Apparatus and method for controlling exposure of a solidifiable medium using a pulsed radiation source in building a three-dimensional object

    公开(公告)号:AU6978398A

    公开(公告)日:1998-11-24

    申请号:AU6978398

    申请日:1998-04-22

    Applicant: 3D SYSTEMS INC

    Abstract: Methods and apparatus for forming three-dimensional objects from a medium solidifiable when subjected to a beam of pulsed radiation wherein the pulses of radiation are made to occur when the beam is directed to desired pulsing locations on a target surface of the medium. Preferred embodiments of the instant invention include a pulsed laser assembly, including a laser and a pulse generation circuit, a control computer, a plurality of mirrors and mirror encoders. The computer controls the movement of the mirrors which guide the laser beam across the surface of the solidifiable medium. The pulsing of the laser beam is correlated to the position of the mirrors and thus, is not dependent upon time. Pulsing linked to position of beam placement allows controlled and repeatable use of a pulsed beam for the formation of objects.

    STEREOLITHOGRAPHIC CURL REDUCTION
    29.
    发明专利

    公开(公告)号:CA1339750C

    公开(公告)日:1998-03-17

    申请号:CA596827

    申请日:1989-04-17

    Applicant: 3D SYSTEMS INC

    Abstract: 94 An improved stereolithography system for generating a three-dimensional object by creating a cross-sectional pattern of the object to be formed at a selected surface of a fluid medium capable of altering its physical state in response to appropriate synergistic stimulation by impinging radiation, particle bombardment or chemical reaction, information defining the object being structurally specified to reduce curl, stress and distortion in the ultimately formed object, the successive adjacent laminae, representing corresponding successive adjacent cross-sections of the object, being automatically formed and integrated together to provide a step-wise laminar buildup of the desired object, whereby a three-dimensional object is formed and drawn from a substantially planar surface of the fluid medium during the forming process. A stereolithographic distortion known as curl is defined, and several techniques to eliminate or reduce curl are described, including dashed line, bent line, secondary structure, rivets, and multi-pass techniques. In addition, a quantitative measurement of curl known as the curl factor, and a test part known as a quarter cylinder are described, which together can be used to measure the effectiveness of the above techniques in reducing curl.

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