US 6,048,188 A · Stereolithographic curl reduction

Abstract

An improved stereolithography system for generating a three-dimensional object by creating a cross-sectional pattern of the object to 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.

Claims43

Dependent claims

An improved apparatus for forming at least a portion of a three-dimensional object from a material capable of solidification upon exposure to synergistic stimulation, the apparatus comprising a source of the synergistic stimulation and a control device controlling the exposure, wherein the improvement comprises:

an improvement to the control device characterized in that the control device is adapted to specify at least one critical region of the object,
to additionally expose any non-critical regions of the object using a first set of exposure parameters, and
to additionally expose the at least one critical region of the object using a second set of exposure parameters which differ from the first set, wherein the second set of exposure parameters are chosen to achieve reduced distortion of the object.

An apparatus for forming a three-dimensional object from a plurality of superposed laminae each formed by the selective solidification of a layer of a transformable medium by exposure to a synergistic stimulation, comprising:

a source of the layer of transformable medium, the layer being adjacent to a previously formed lamina of the object;
a source of synergistic stimulation;
and
a control device operably connected to at least the source of synergistic stimulation, the control device controlling at least the exposure, wherein the control device is operable according to a prescribed program to apply at least one initial exposure of synergistic stimulation to the layer according to a first predetermined pattern to form an initial section of a subsequent lamina after the previously formed lamina, and to apply at least one further exposure of synergistic stimulation to the layer according to a second predetermined pattern to form a further section of the subsequent lamina at least partially adhering the subsequent lamina to the previously formed lamina to form the three-dimensional object, wherein adherence of the subsequent lamina and the previously formed lamina is specified to occur on the at least one further exposure.

1 more element

Dependencies are inferred from the claim text.

Stereolithographic curl reduction

Life of this patent

Stereolithographic curl reduction

Life of this patent

Abstract

Claims43