A process for creating batches of unvulcanized rubber before mixing in a rubber mixer, including selecting at least one batch for mixing in the mixer, wherein each batch corresponds to a selection of rubber bales (A I , B I , C I ) that each correspond to a nature of rubber composition (A, B, C) having predetermined characteristics, the method comprising the following steps: providing a supply station where uncured rubber bales (A I , B I , C I ) are supplied from the corresponding rubber natures (A, B, C); selecting unvulcanized rubber bales (A I , B I , C I ) from the rubber natures (A, B, C) and in a predetermined proportion corresponding to a batch selected at the supply station , wherein each batch comprises rubber types and grades from different suppliers, rubbers of different types from the same supplier, or a combination of the two; providing a cutting station comprising at least three cutting subassemblies (118, 118', 118") for cutting at least one bale (A I , B I , C I ) into pieces (A IJ , B IJ . C IJ ) and each cutting subassembly (118, 118', 118") is coupled with a respective linear actuator (120, 120', 120") that adjusts the position of a bale (A I , B I , C I ) according to a recipe for the rubber mixture; providing a transport system that feeds the cutting subassemblies (118, 118', 118") and that transfers the bales (A I , B I , C I ) and the pieces (A IJ , B IJ . C IJ ) of rubber toward at least one mixer; weighing the bales (A I , B I , C I ) to obtain the weight of the bales (A I , B I , Ci); comparing the weight of the bales (A I , B I , C I ) with the required weight of the batch; and transporting the bales (A I , B I , C I ) and the pieces (A IJ , B IJ . C IJ ) between the supply station , via feed belt to the cutting station and the mixer according to a sequence determined by the equivalence between the required weight of the batch and (a) the weight of the bales (A I , B I , C I ) or (b) a sum of the weight of the bales (A I , B I , C I ) and a weight of the pieces (A IJ , B IJ . C IJ ). providing a supply station where uncured rubber bales (A I , B I , C I ) are supplied from the corresponding rubber natures (A, B, C); selecting unvulcanized rubber bales (A I , B I , C I ) from the rubber natures (A, B, C) and in a predetermined proportion corresponding to a batch selected at the supply station , wherein each batch comprises rubber types and grades from different suppliers, rubbers of different types from the same supplier, or a combination of the two; providing a cutting station comprising at least three cutting subassemblies (118, 118', 118") for cutting at least one bale (A I , B I , C I ) into pieces (A IJ , B IJ . C IJ ) and each cutting subassembly (118, 118', 118") is coupled with a respective linear actuator (120, 120', 120") that adjusts the position of a bale (A I , B I , C I ) according to a recipe for the rubber mixture; providing a transport system that feeds the cutting subassemblies (118, 118', 118") and that transfers the bales (A I , B I , C I ) and the pieces (A IJ , B IJ . C IJ ) of rubber toward at least one mixer; weighing the bales (A I , B I , C I ) to obtain the weight of the bales (A I , B I , Ci); comparing the weight of the bales (A I , B I , C I ) with the required weight of the batch; and transporting the bales (A I , B I , C I ) and the pieces (A IJ , B IJ . C IJ ) between the supply station , via feed belt to the cutting station and the mixer according to a sequence determined by the equivalence between the required weight of the batch and (a) the weight of the bales (A I , B I , C I ) or (b) a sum of the weight of the bales (A I , B I , C I ) and a weight of the pieces (A IJ , B IJ . C IJ ). <EOS>