US 12,251,882 B2
Method of printing a three-dimensional object comprising a plurality of discrete elements
Lior Elgali, Tel-Aviv (IL); and Naftali Emanuel Eder, Kiryat Gat (IL)
Assigned to STRATASYS LTD., Rehovot (IL)
Appl. No. 17/789,872
Filed by STRATASYS LTD., Rehovot (IL)
PCT Filed Dec. 30, 2020, PCT No. PCT/IL2020/051358
§ 371(c)(1), (2) Date Jun. 29, 2022,
PCT Pub. No. WO2021/137232, PCT Pub. Date Jul. 8, 2021.
Claims priority of provisional application 62/956,257, filed on Jan. 1, 2020.
Prior Publication US 2023/0052977 A1, Feb. 16, 2023
Int. Cl. B33Y 10/00 (2015.01); B29C 64/171 (2017.01); B29C 64/393 (2017.01); B33Y 50/02 (2015.01)
CPC B29C 64/393 (2017.08) [B29C 64/171 (2017.08); B33Y 10/00 (2014.12); B33Y 50/02 (2014.12)] 16 Claims
OG exemplary drawing
 
1. A method of printing a 3D object comprising a plurality of discrete elements, the method comprising:
receiving a 3D digital model of a shell group comprising one or more shells representing the plurality of discrete elements;
defining, in the 3D digital model, a unifying shell to at least partly envelop one or more shells of the shell group so as to provide a unified 3D digital model comprising the shell group and the unifying shell;
assigning the unifying shell of the unified 3D digital model with at least one transparent building material, wherein the at least one transparent building material is transparent upon dispensing and solidifying thereof;
assigning the one or more shells of the shell group of the unified 3D digital model with one or more building materials;
generating a set of slices of the unified 3D digital model, wherein each of the slices corresponds to a planar slice of the unified 3D digital model and comprises at least one of
a first subset of slice data values that belong to the shell group,
a second subset of slice data values that belong to the unifying shell, and
a third subset of slice data values that belong to both the shell group and the unifying shell;
assigning the slice data values of the first subset with at least one of the one or more building materials;
assigning the slice data values of the second subset with the at least one transparent building material;
assigning the slice data values of the third subset with at least one of the one or more building materials and the at least one transparent building material according to an overlapping rule;
assigning at least some of the slice data values that belong to a region between two or more shells of the shell group with one or more supporting materials when the distance between the two or more shells thereof is above a predetermined distance threshold; and
dispensing, in layers, the at least one transparent building material and the one or more building materials, according to the unified 3D digital model and according to the set of slices of the unified 3D digital model and the materials assigned therewith to form the 3D object comprising the one or more discrete elements that are at least partly connected by a unifying element.