Method for the layered construction of a shaped body made of highly viscous photopolymerizable material

1. Method for a layered construction of a shaped body made of highly viscous photopolymerizable material, in which a production platform, on a lower side of which a first layer of the shaped body to be constructed is cured, is lowered into a tank into the photopolymerizable material to a height determined so that a layer of photopolymerizable material with a predetermined layer thickness is defined between the lower side of the production platform or, if already present, a lowest cured layer of the shaped body part formed thereon and a tank bottom, the layer is exposed and cured in a desired shape by selective exposure from below through a transparent tank bottom, the production platform is raised again, an exposed region below the raised platform is replenished with photopolymerizable material and the preceding steps are repeated until a last layer of the shaped body is formed, wherein in order to replenish the exposed region below the production platform with photopolymerizable material, an elongate mixing element is moved essentially transversely to its longitudinal direction over the tank bottom, relative thereto, below the production platform through the exposed region, and wherein the mixing element has dimensions, and is moved in a positioned fashion, such that the upper edge of the mixing element remains below a material level of the photopolymerizable material, which exists outside the exposed region in the tank, at least along a part of its length, and wherein an oscillating movement of the elongate mixing element along its longitudinal direction is superimposed on movement of the elongate mixing element essentially transversely to its longitudinal direction.

2. Method for the layered construction of a shaped body according to claim 1 , wherein the elongate mixing element is moved in a positioned fashion in such a way that the lower edge of the mixing element is in contact with the tank bottom during its movement parallel to the tank bottom.

3. Method for the layered construction of a shaped body according to claim 1 , wherein the elongate mixing element is moved in a positioned fashion in such a way that the lower edge of the mixing element is at a predetermined distance from the tank bottom during its movement parallel thereto.

4. Method for the layered construction of a shaped body according to claim 1 , wherein the elongate mixing element comprises a wire, which is held parallel to the tank bottom, over the tank bottom and movably relative thereto.

5. Method for the layered construction of a shaped body according to claim 4 , wherein the wire comprise a metal wire.

6. Method for the layered construction of a shaped body according to claim 4 , wherein the wire has a diameter in the range of from 0.1 mm to 1 mm.

7. Method for the layered construction of a shaped body according to claim 1 , wherein the elongate mixing element is resistively heatable and is resistively heated during the movement below the shaped body part in order to increase the local temperature of the surrounding photopolymerizable material and thereby reduce its viscosity.

8. Method for the layered construction of a shaped body according to claim 1 , wherein in order to replenish the photopolymerizable material, the elongate mixing element is moved with respect to a stationary tank through the region of the production platform over the tank bottom.

9. Method for the layered construction of a shaped body according to claim 1 , wherein in order to replenish the photopolymerizable material, the tank is moved with respect to a stationary elongate mixing element, such that the elongate mixing element is moved through the region of the production platform over the tank bottom.

10. Method for the layered construction of a shaped body according to claim 1 , wherein the elongate mixing element is moved through below the shaped body part on the production platform at least twice in order to replenish the photopolymerizable material.

11. Method according to claim 1 , wherein the frequency of the oscillating movement of the elongate mixing element is so great that the elongate mixing element is moved several times to and fro along its longitudinal direction while it passes once through the region below the shaped body part of the production platform.

12. Method for the layered construction of a shaped body according to claim 1 , wherein the elongate mixing element comprises regions with an enlarged cross section and a reduced cross section alternating along its length.

13. Method for the layered construction of a shaped body according to claim 1 , characterized in that the elongate mixing element is provided in the form of an elongate rod which has a round, triangular or polygonal cross-sectional shape or which is formed as an L-, U-, or O-shaped profile.

14. Method for the layered construction of a shaped body according to claim 4 , wherein the elongate mixing element comprises a plurality of parallel wires, which are moved over the tank bottom while being aligned one behind the other at the same height above the tank bottom or at different heights above the tank bottom.

15. Method for the layered construction of a shaped body according to claim 2 , wherein the elongate mixing element has a resilient sealing lip over its entire length, which lip is moved over the tank bottom in contact with the tank bottom during the movement of the elongate mixing element.

16. Method for a layered construction of a shaped body made of highly viscous photopolymerizable material, in which a production platform, on a lower side of which a first layer of the shaped body to be constructed is cured, is lowered into a tank into the photopolymerizable material to a height determined so that a layer of photopolymerizable material with a predetermined layer thickness is defined between the lower side of the production platform or, if already present, a lowest cured layer of the shaped body part formed thereon and a tank bottom, the layer is exposed and cured in a desired shape by selective exposure from below through a transparent tank bottom, the production platform is raised again, an exposed region below the raised platform is replenished with photopolymerizable material and the preceding steps are repeated until a last layer of the shaped body is formed, wherein in order to replenish the exposed region below the production platform with photopolymerizable material, an elongate mixing element is moved essentially transversely to its longitudinal direction over the tank bottom, relative thereto, below the production platform through the exposed region, and wherein the mixing element has dimensions, and is moved in a positioned fashion, such that the upper edge of the mixing element remains below a material level of the photopolymerizable material, which exists outside the exposed region in the tank, at least along a part of its length, and wherein the elongate mixing element comprises regions with an enlarged cross section and a reduced cross section alternating along its length.

17. Method for a layered construction of a shaped body made of highly viscous photopolymerizable material, in which a production platform, on a lower side of which a first layer of the shaped body to be constructed is cured, is lowered into a tank into the photopolymerizable material to a height determined so that a layer of photopolymerizable material with a predetermined layer thickness is defined between the lower side of the production platform or, if already present, a lowest cured layer of the shaped body part formed thereon and a tank bottom, the layer is exposed and cured in a desired shape by selective exposure from below through a transparent tank bottom, the production platform is raised again, an exposed region below the raised platform is replenished with photopolymerizable material and the preceding steps are repeated until a last layer of the shaped body is formed, wherein in order to replenish the exposed region below the production platform with photopolymerizable material, an elongate mixing element is moved essentially transversely to its longitudinal direction over the tank bottom, relative thereto, below the production platform through the exposed region, and wherein the mixing element has dimensions, and is moved in a positioned fashion, such that the upper edge of the mixing element remains below a material level of the photopolymerizable material, which exists outside the exposed region in the tank, at least along a part of its length, wherein the elongate mixing element comprises a wire, which is held parallel to the tank bottom, over the tank bottom and movably relative thereto, and wherein the elongate mixing element comprises a plurality of parallel wires, which are moved over the tank bottom while being aligned one behind the other at the same height above the tank bottom or at different heights above the tank bottom.

18. Method for a layered construction of a shaped body made of highly viscous photopolymerizable material, in which a production platform, on a lower side of which a first layer of the shaped body to be constructed is cured, is lowered into a tank into the photopolymerizable material to a height determined so that a layer of photopolymerizable material with a predetermined layer thickness is defined between the lower side of the production platform or, if already present, a lowest cured layer of the shaped body part formed thereon and a tank bottom, the layer is exposed and cured in a desired shape by selective exposure from below through a transparent tank bottom, the production platform is raised again, an exposed region below the raised platform is replenished with photopolymerizable material and the preceding steps are repeated until a last layer of the shaped body is formed, wherein in order to replenish the exposed region below the production platform with photopolymerizable material, an elongate mixing element is moved essentially transversely to its longitudinal direction over the tank bottom, relative thereto, below the production platform through the exposed region, and wherein the mixing element has dimensions, and is moved in a positioned fashion, such that the upper edge of the mixing element remains below a material level of the photopolymerizable material, which exists outside the exposed region in the tank, at least along a part of its length, wherein the elongate mixing element is moved in a positioned fashion in such a way that the lower edge of the mixing element is in contact with the tank bottom during its movement parallel to the tank bottom, and wherein the elongate mixing element has a resilient sealing lip over its entire length, which lip is moved over the tank bottom in contact with the tank bottom during the movement of the elongate mixing element.