Force-regulated additive manufacturing

Abstract

A method of forming a three-dimensional object () includes the steps of: (a) providing an apparatus including a carrier (), a light transmissive window () having a build surface, polymerizable liquid () on the build surface, and a growing object () on the carrier, the growing object produced by light polymerization of the polymerizable liquid; (b) vertically reciprocating the carrier () with respect to the build surface in an upstroke and a downstroke, the downstroke being shorter than the upstroke, to form a build region between the growing object and the build surface, and to fill the build region with the polymerizable liquid, while also: (i) sensing force exerted between the carrier and the build surface through the growing object () and the polymerizable liquid () during the upstroke; and (ii) modifying the speed, acceleration, or both speed and acceleration of the upstroke in response to the sensed force so that the sensed force approaches a predetermined target force; then (c) irradiating the build region with light through the light transmissive window to form a new portion of the object from the polymerizable liquid on the growing object; and then (d) repeating steps (b) through (c) to form additional portions on the growing object until the three-dimensional object is formed.