Device And Method For Processing Light-Polymerizable Material For Building Up An Object In Layers

A device for processing light-polymerizable material for building up an object in layers, using lithography-based generative fabrication, comprising

• a build platform for building up the object,
• a projecting exposure unit, which can be controlled for position selective exposure of a surface on the build platform with an intensity pattern with prescribed form, and
• a control unit, which is arranged to polymerize in successive exposure steps layers lying one above the other on the build platform, respectively with prescribed geometry, by controlling the projecting exposure unit, in order in this way to build up the object successively in the desired form, which results from the sequence of the layer geometries, and
• a further exposure unit for exposing the surface area of the build platform from the side opposite from the projecting exposure unit, the build platform being formed such that it is at least partially transparent or translucent and the control unit being designed to control the further exposure unit, at least while building up the first layer, which adheres to the build platform, for exposure in the prescribed geometry,
• at least one vat with an at least partially transparently or translucently formed bottom, into which light-polymerizable material can be filled, wherein the build platform is held by a lifting mechanism above the vat bottom, so that its height in relation to the vat bottom can be set, and wherein the control unit is arranged to adapting the relative position of the build platform to the vat bottom by controlling the lifting mechanism after each exposure step for a layer, in that, after renewed feeding of light-polymerizable material, the build platform with the layers formed on it, if any are present, is lowered again into the newly fed light-polymerizable material, so that light-polymerizable material is displaced from the remaining intermediate space with respect to the vat bottom, and the distance between the lowered lower surface of the build platform or of the layer last formed on it and the vat bottom is set in a prescribed manner.