James Alan Maxwell

US Patent:

57860238, Jul 28, 1998

Filed:

Feb 13, 1996

Appl. No.:

8/600454

Inventors:

James L. Maxwell - Tallahassee FL
Joseph Pegna - Clifton Park NY

International Classification:

C23C 800
B05D 312
C04B 4000

US Classification:

427 8

Abstract:

Method and apparatus for the selective heat-induced deposition of solid material from gas-phase or super-critical fluids to produce three-dimensional parts by pyrolysis of the fluids. The apparatus involves computer/feedback control of the evolving shape by direct monitoring of the volumetric deposition rate or growth profile, and modifying light beam focal properties, the position and orientation of the deposit relative to the beam foci, and/or the pressure and flow of reactants to the growth zone. The precursor gases may be pressurized and heated to the critical point or beyond, becoming super-critical fluids, without condensation. Growth occurs by diffusion of reactants to the growth zone through a boundary layer over the deposit. One method of growth includes directing a large-area impinging jet of precursor fluid(s) onto a deposit interface, while limiting the reaction zone to a smaller area determined solely by size of the heated zone (through use of a radiant beam, e. g. ). Another method comprises directing a small-area impinging jet of precursor fluid onto a deposit interface, where the heated region is larger than the jet size.