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

Claim 16:
17. A non-transient storage media storing software instructions, that when executed by a processor, operate a 3D printing system to fabricate a 3D article, the 3D printing system including:
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; and
a volume compensator (VC); and
when executed by the processor, the software instructions perform the following steps:
monitoring the resin level sensor and operate the volume compensator (VC) to maintain a resin upper surface coincident to the build plane within a specified vertical tolerance range;
operating the vertical positioner and the imaging system to generate a plurality of base layers upon the plate upper surface;
receiving a first signal responsive to vertical motion of the resin upper surface;
while forming the plurality of base layers, analyzing the first signal to determine 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
operating the imaging system and the vertical positioner to begin generation of the 3D article after the slope has decreased below a 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.