In automotive industry, tires play a key role. They are a composite structure formed by multiple layers of different materials such as rubber compounds, steel and polyamide cords. Between the tread and steel belts, a cap ply layer is used to restrict the growth of the tire, due to centrifugal forces. Cap ply is produced by using a pultrusion process that impregnates polyamide cords with rubber, resulting in a rubberized strip. When the controlling of the process is incorrect, premature vulcanization or lack of impregnation is often observed. To optimize the production process, CFD (Computational Fluid Dynamics) simulations were performed to study the flow of rubber inside the extrusion head channels by modelling the fluid properties and the domain. Laboratory tests were also conducted to determine the physical and cure properties of the rubber compound used. Crossing the results of the simulations with the laboratory tests was found that the temperature control used was inadequate. Simulations were also supported with the results provided by a temperature sensor controlled by an external device (Arduino). By using a proportional integral derivative controller and changing the setpoints for the thermal resistance, the amount of scrap generated by vulcanized rubber and lack of rubber in the cap ply strips was reduced by 100%.