Abstract: A method for increasing productivity and quality in production of cured polymer by a real time measurement of the progress of curing, in a mould cavity, which being filled with a compound to be cured, wherein a signal is generated by a wave at an ultrasonic or equivalent frequency, which is transmitted through the mould cavity, the time for the wave to pass through the compound in the mould and back is detected, and the detected signal being analyzed in a suitable data processing computer , to establish a graph showing a relationship between the time for the wave to pass through the compound in the mould and back, and the time of the curing of the compound. The graph is used to determine a feature of the compound by identifying at least one specific parameter of the graph, and using said parameter to control the production.