Plaster mould making is an important stage of the porcelain production. After being mixed with plaster and water, moulding has to be completed in 6-7 minutes and the first 2-3 minutes are spent with mixing. During such an operation which needs to be performed at this speed, the water and plaster must be measured accurately for having the mould to the required quality and they should be mixed in a vacuum to avoid air bubbles. Therefore, the plaster preparation unit consists of a scale and a mixer with vacuum.