Method for determining the material layer thickness of material plies in the production of tyre components comprising the following steps: a) providing a tyre component by a device for producing tyre components, the tyre component being produced in the form of a material ply and as a continuous material, b) continuously conveying the tyre component along a conveying section, a terahertz sensor being arranged above and/or below the tyre component , the terahertz sensor being arranged on a frame , c) carrying out a continuous material layer thickness measurement on the tyre component , the terahertz sensor being moved back and forth transversely in relation to the conveying direction above the tyre component and the terahertz sensor thereby being moved on the frame at a speed of between 50 and 400 mm/s, a terahertz radiation being generated by the terahertz sensor , reflections in the form of echoes being produced at the material boundaries in the tyre component , at least one material layer thickness of the respective material layer in the tyre component being determined by the transit times of the echoes determined by the terahertz sensor , f) continuously evaluating the received measurement signals by software and monitoring the material layer thickness of the respective material layer of the tyre component , the determined material layer thickness of the respective material layer being compared in each case with a prescribed material layer thickness of the respective material layer, g) continuously carrying on with the production process for the tyre component as long as no deviation from a prescribed material layer thickness of the respective material layer is detected. a) providing a tyre component by a device for producing tyre components, the tyre component being produced in the form of a material ply and as a continuous material, b) continuously conveying the tyre component along a conveying section, a terahertz sensor being arranged above and/or below the tyre component , the terahertz sensor being arranged on a frame , c) carrying out a continuous material layer thickness measurement on the tyre component , the terahertz sensor being moved back and forth transversely in relation to the conveying direction above the tyre component and the terahertz sensor thereby being moved on the frame at a speed of between 50 and 400 mm/s, a terahertz radiation being generated by the terahertz sensor , reflections in the form of echoes being produced at the material boundaries in the tyre component , at least one material layer thickness of the respective material layer in the tyre component being determined by the transit times of the echoes determined by the terahertz sensor , f) continuously evaluating the received measurement signals by software and monitoring the material layer thickness of the respective material layer of the tyre component , the determined material layer thickness of the respective material layer being compared in each case with a prescribed material layer thickness of the respective material layer, g) continuously carrying on with the production process for the tyre component as long as no deviation from a prescribed material layer thickness of the respective material layer is detected. <EOS>