Two-phase 3D printing method

A process for producing an article comprising:

• I) depositing a free-radically crosslinked resin on a carrier to obtain a ply of a construction material joined to the carrier which corresponds to a first selected cross section of the article;
• II) depositing a free-radically crosslinked resin on a previously deposited ply of the construction material to obtain a further ply of the construction material which corresponds to a further selected cross section of the article and is joined to the previously applied ply;
• III) repeating step II) until the article is formed;
• wherein depositing a free-radically crosslinked resin at least in step II) further comprises illuminating and/or irradiating a selected region of a free-radically crosslinkable resin corresponding to the respective selected cross section of the article, wherein the free-radically crosslinkable resin comprises a urethane (meth)acrylate,
• wherein the carrier is arranged inside a container containing the free-radically crosslinkable resin and a liquid immiscible with the free-radically crosslinkable resin and which has a higher density than the free-radically crosslinkable resin causing the free-radically crosslinkable resin to float on the liquid, and
• wherein, before each step II), the method further comprises altering a distance between the carrier and the free-radically crosslinkable resin to form a layer of the free-radically crosslinkable resin above a vertically uppermost surface of the previously deposited ply of the construction material and that at least partially contacts the uppermost surface of the previously deposited ply of the construction material, and
• at least once during the process, re-adding a proportion of the free-radically crosslinkable resin withdrawn by deposition of the free-radically crosslinked resin.