1. Researcher, CARTIF Centro Tecnológico, Parque Tecnológico de Boecillo, 205, 47151 Valladolid, Spain (corresponding author).
2. Senior Lecturer, Institute of Advanced Production Technologies (ITAP), Univ. of Valladolid, Paseo del Cauce, 59, 47011 Valladolid, Spain.
3. Lecturer, Institute of Advanced Production Technologies (ITAP), Univ. of Valladolid, Paseo del Cauce, 59, 47011 Valladolid, Spain.