Patent ID: 11919230
Assignee: 3D SYSTEMS, INC.
Field: Other special machines (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A three-dimensional (3D) printing system for manufacturing a three-dimensional (3D) article comprising:
a resin vessel for containing a volume of resin having a resin upper surface;
an imaging system configured to selectively cure a layer of the resin over a build plane;
a build plate having a plate upper surface that defines a vertical height difference H over which the 3D article is to be fabricated due to curvature and/or defining an oblique angle of the plate upper surface relative to the horizontal build plane;
a vertical positioner;
a resin level sensor;
a volume compensator (VC); and
a controller configured to:
operate the VC to maintain the resin upper surface coincident to the build plane to within a specified vertical tolerance range;
operate the imaging system and the vertical positioner to generate a plurality of base layers upon the plate upper surface;
receive a first signal responsive to vertical motion of the resin upper surface;
while forming the plurality of base layers, analyze the first signal to determine a slope of a volume compensation versus time curve having an initial base part of the curve having an initial slope indicative of forming layers over an angled and/or curved surface and a build part of the curve having a slope that is of lower magnitude than the initial slope indicative of forming layers over a horizontal planar surface; and

operate the imaging system and the vertical positioner to begin generation of the 3D article after the slope has decreased below a predefined threshold at which the plurality of base layers have compensated for the vertical height difference H and have covered the angled and/or curved surface and define a horizontal plane over which the 3D article is generated.