Continuous liquid interphase printing
A method of forming a three-dimensional object is carried out by providing a carrier and an optically transparent member having a build surface, the carrier and the build surface defining a build region therebetween; filling the build region with a polymerizable liquid; irradiating the build region through the optically transparent member to form a solid polymer from the polymerizable liquid and advancing the carrier away from the build surface to form the three-dimensional object from the solid polymer, while also concurrently with the irradiating and/or advancing steps: (i) continuously maintaining a dead zone of polymerizable liquid in contact with the build surface, and (ii) continuously maintaining a gradient of polymerization zone between the dead zone and the solid polymer and in contact with each thereof. The gradient of polymerization zone comprises the polymerizable liquid in partially cured form (e.g., so that the formation of fault or cleavage lines between layers of solid polymer in the three-dimensional object is reduced). Apparatus for carrying out the method is also described.
1. A method of forming a three-dimensional object, comprising the steps of:
(a) providing a carrier and a build plate, the build plate comprising a semipermeable member, and the semipermeable member comprising a build surface, with the build surface and the carrier defining a build region therebetween, and the build surface in fluid communication by way of the semipermeable member with a source of polymerization inhibitor;
(b) filling the build region with a polymerizable liquid, the polymerizable liquid contacting the build surface,
(c) irradiating the build region through the build plate to produce a solid polymerized region in the build region, while forming or maintaining a liquid film release layer comprised of the polymerizable liquid formed between the solid polymerized region and the build surface, wherein polymerization of the liquid film release layer is inhibited by the polymerization inhibitor; and
(d) advancing the carrier with the polymerized region adhered thereto away from the build surface to create a subsequent build region between the polymerized region and the build surface while concurrently filling the subsequent build region with polymerizable liquid as in step (b);
(e) continuing and/or repeating steps (c) and (d) to produce a subsequent polymerized region adhered to a previous polymerized region until a continued or repeated deposition of polymerized regions adhered to one another forms the three-dimensional object,
wherein the polymerizable liquid comprises a photocurable polyurethane.
2. The method of claim 1 , wherein the polymerizable liquid comprises a polyurethane based on an aliphatic diisocyanate, a polyfunctional acrylic ester, a photoinitiator, and an antioxidant.
3. The method of claim 2 , wherein the aliphatic diisocyanate is poly(hexamethylene isophthalate glycol).
4. The method of claim 2 , wherein the polymerizable liquid further comprises 1,4-butanediol.
5. The method of claim 1 , wherein the polymerizable liquid further comprises a photoinitiator, and optionally a pigment or dye.
6. The method of claim 1 , wherein steps (c) and (d) are carried out concurrently.
7. The method of claim 1 , wherein the liquid film release layer comprises a dead zone of polymerizable liquid in contact with the build surface, and a gradient of polymerization zone between the dead zone and the solid polymerized region and in contact with each thereof, the gradient of polymerization zone comprising the polymerizable liquid in partially cured form.
8. The method of claim 7 , wherein the gradient of polymerization zone and the dead zone together have a thickness of from 1 to 1000 microns.
9. The method of claim 7 , wherein the gradient of polymerization zone is maintained for a time of at least 30 seconds.
10. The method of claim 7 , wherein the gradient of polymerization zone is maintained until completion of the three-dimensional object.
11. The method of claim 1 , further comprising the step of monitoring or detecting at least one process parameter and/or providing at least one known or predetermined process parameter; and then
altering at least one process parameter in response to the monitored process parameter or known or predetermined process parameter.
12. The method of claim 11 , wherein the process parameter is a rate of supply of polymerizable liquid, temperature, pressure, rate or speed of advance of carrier, intensity of irradiation, or duration of irradiation.
13. The method of claim 1 , wherein the polymerizable liquid comprises a free radical polymerizable liquid and the polymerization inhibitor comprises oxygen.
14. The method of claim 1 , wherein the semipermeable member comprises a fluoropolymer film.
15. A three-dimensional object produced by the method of claim 1 .
16. A method of forming a three-dimensional object, comprising: providing a carrier and an optically transparent member having a build surface, the carrier and the build surface defining a build region therebetween; filling the build region with a polymerizable liquid; irradiating the build region through the optically transparent member to form a solid polymer from the polymerizable liquid while concurrently advancing the carrier away from the build surface to form the three-dimensional object from the solid polymer, while also concurrently: (i) continuously maintaining a dead zone of polymerizable liquid in contact the build surface, and (ii) continuously maintaining a gradient of polymerization zone between the dead zone and the solid polymer and in contact with each thereof, the gradient of polymerization zone comprising the polymerizable liquid in partially cured form, wherein the polymerizable liquid comprises a photocurable polyurethane.
17. The method of claim 16 , wherein the gradient of polymerization zone and the dead zone together have a thickness of from 1 to 1000 microns.
18. The method of claim 16 , wherein the gradient of polymerization zone is maintained for a time of at least 30 seconds.
19. The method of claim 16 , wherein the gradient of polymerization zone is maintained until completion of the three-dimensional object.
20. A three-dimensional object produced by the method of claim 16 .