Method and system for additive manufacturing of peelable sacrificial structure
A method of additive manufacturing of a three-dimensional object includes sequentially dispensing and solidifying a plurality of layers. The plurality of layers may be formed with a plurality of different colored model materials, a flexible material arranged in a configured pattern to form a sacrificial structure at least partially encompassing the object, and a soft material. The soft material is arranged in a configured pattern to provide separation between the model material and the sacrificial structure. The plurality of different colored model materials is arranged in a configured pattern corresponding to the shape and color definition of the object.
1 . An additive manufacturing (AM) system for fabricating a three-dimensional colored object, the system comprising:
a set of supply cartridges with different colored model materials, a cartridge containing a flexible material, and a cartridge containing a soft material, the soft material having an elastic modulus less than the flexible material;
nozzle arrays mounted in dispensing heads configured to receive materials from the supply cartridges;
a solidification system configured for solidifying the materials dispensed from the dispensing heads; and
a computerized controller having a circuit configured for operating the dispensing heads and the solidification system to sequentially dispense and solidify a plurality of layers comprising (i) a plurality of different colored model materials received from said set of supply cartridges and arranged in a configured pattern corresponding to a shape and a color definition of the object, (ii) the flexible material arranged in a configured pattern to form a sacrificial structure at least partially encompassing the object, and (iii) the soft material arranged in a configured pattern to provide an intermediate structure between at least one model material of said plurality of different colored model materials and the sacrificial structure;
wherein the flexible material is black and said circuit is configured to ensure that said nozzle arrays form a first black region of the object by an amount of said black flexible material, and a second black region of the object by digitally mixing the plurality of different colored model materials to create a black color.
2 . The AM system of claim 1 , wherein the plurality of different color model materials does not include black model material.
3 . AM system of claim 1 , wherein said second black color region has a volume that is larger than a defined threshold, and said first black color region has a volume that is smaller or equal said defined threshold.
4 . The AM system of claim 1 , wherein the soft material is arranged in a configured pattern to form divisions in the sacrificial structure.
5 . The AM system according to claim 4 , wherein the divisions are formed on symmetrical planes to the object.
6 . The AM system of claim 1 , wherein the soft material is arranged in a configured pattern to fill holes defined by geometry of the object.
7 . The AM system of claim 6 , wherein the soft material is arranged in a configured pattern to form divisions in the sacrificial structure.
8 . The AM system of claim 1 , wherein the soft material is configured to encompass breakable features.
9 . The AM system of claim 1 , wherein there are up to six supply cartridges in the set of supply cartridges.
10 . The AM system of claim 1 , comprising up to three dispensing heads.
11 . The AM system of claim 10 , wherein there are up to six supply cartridges in the set of supply cartridges.
12 . The AM system of claim 1 , wherein a thickness of the intermediate structure between the model material and the sacrificial structure provided by the soft material is 100 microns to 300 microns.
13 . The AM system of claim 1 , wherein a thickness of the sacrificial structure is from about 500 microns to about 3 mm.
14 . The AM system of claim 1 , wherein a of the soft material is from about 1 to about 50 voxels.
15 . The AM system of claim 1 , wherein a of the soft material is from about 10 to about 500 microns.
16 . The AM system of claim 1 , wherein a thickness of the sacrificial structure is selected such that a peeling force of about 5 N results in a bending strain of at least 0.02.
17 . The AM system of claim 1 , wherein the sacrificial structure is characterized, once solidified, by a tear resistance of from about 4 kN per meter to about 8 kN per meter, when measured according to international standard ASTM D-624.