The work deals with technology Patternless process that combines 3 manufacturing process mold by using rapid prototyping technology, conventional sand formation and 3D milling. It's unconventional technology that has been developed to produce large-sized and heavyduty castings weighing up to several tons. It is used mainly in prototype and small batch production, because eliminating production of models. The work deals with the production of blocks for making molds of gypsum and gypsum drying process technology Thermomold. Into blocks, where were made cavities by milling were casted test castings from AlSi10MgMn alloy by gravity casting. At machining of the mold cavity was varied feed rate of tool of cemented carbide. Evaluated was the surface roughness of test castings, that was to 5 micrometers with feed from 900 to 1300 mm/min. The dimensional accuracy of castings was high at feed rate of 1000 and 1500 mm/min did not exceed 0.025 mm.