Techniques for casting from additively fabricated molds and related systems and methods
According to some aspects, a method is provided of casting an object from a mold, the method comprising obtaining a mold comprising a hollow shell of rigid material, the material comprising a thermoset polymer having a plurality of pores formed therein, providing a metal and/or ceramic slurry into an interior of the mold, exposing at least part of the mold to a low pressure environment so that a net flow of gas is produced from the interior of the mold into the low pressure environment. According to some aspects, a method of forming a porous mold is provided. According to some aspects, a photocurable liquid composition is provided, comprising a liquid photopolymer resin, particles of a solid material, in an amount between 30% and 60% by volume of the composition, and a water-soluble liquid.
1. A method of forming a porous object, the method comprising:
forming, via additive fabrication, an object comprising a hollow shell of rigid material, wherein the material comprises a thermoset polymer and a plurality of solid particles embedded within the polymer; and
removing at least some of the solid particles from the object, thereby forming a plurality of pores in the hollow shell.
2. The method of claim 1 , wherein the solid particles include particles of NaHCO 3 , and wherein removing the at least some of the solid particles comprises reacting the solid particles with an acidic liquid.
3. The method of claim 1 , wherein the solid particles include particles of a water-soluble salt, and wherein removing the at least some of the solid particles comprises dissolving the solid particles in water.
4. The method of claim 1 , wherein removing the at least some of the solid particles comprises applying heat to the object.
5. The method of claim 1 , wherein forming the object comprises applying radiation to a mixture comprising a liquid photopolymer, thereby curing the liquid photopolymer into the thermoset polymer.
6. The method of claim 1 , wherein a mean size of the plurality of pores is between 20 μm and 100 μm.
7. The method of claim 6 , wherein the mean size of the plurality of pores is between 40 μm and 60 μm.