A process of manufacturing a rubber compound is disclosed. The process comprises providing a multiple shaft extruder device; feeding the multiple shaft extruder device with at least one polymer raw material or with a mixture of at least two different polymer raw materials; feeding the multiple shaft extruder device with at least one further raw material; mixing the at least one polymer raw material or the mixture of the different polymer raw materials and the at least one further raw material in the multiple shaft extruder device to prepare a rubber compound; and extruding the rubber compound from the multiple shaft extruder device. A plurality of multiple shaft extruder devices may be used in parallel or in sequence.