Patent ID: 6172996
Filing Date: 2001-01-09
Classification: B29C,B33Y

Abstract:
A stereolithography apparatus for forming a three-dimensional object from a solidifiable medium, the apparatus comprising:a vessel adapted to hold a solidifiable medium, the solidifiable medium having a target surface defined in or on the solidifiable medium, the three-dimensional object formed layer by layer at least partially, within the vessel;a pulsed source of electromagnetic radiation; anda scanner receiving a beam of electromagnetic radiation from the pulsed source and moving the beam with respect to the target surface in a predefined manner, the scanner exposing the target surface of the solidifiable medium to the beam of pulses of electromagnetic radiation having a desired pulse repetition rate to form a subsequent layer of the three-dimensional object and to adhere the subsequent layer to a previously formed layer,wherein the pulse repetition rate F is selected to be equal to or greater than that given by ##EQU2##wherein V.sub.s is a scanning speed of the beam, W.sub.o is a half width of the beam at 1/e.sup.2 of a peak irradiance distribution of the beam, P.sub.L is a power of the beam, E.sub.c is a critical exposure of the solidifiable medium, C.sub.d is a desired cure depth, and D.sub.p is a penetration depth (1/e absorption depth) of the beam in the solidifiable medium.