US Patent 6838035 Rapid-prototyping method and apparatus

A rapid-prototyping production method for producing a structural body by deposition, in several subsequent deposition steps, of subsequent layers of a building material one onto the other. The building material is selectively deposited in each layer in a liquid state in the form of droplets and being caused to solidify when deposited. After deposition, the layer is lowered into a supporting fluid which has a liquid state and has a density which is at least the same as the density of the building material.