Method and plant for building tyres

A method for building a tyre comprising:

• processing structural elements comprising initial components and semi-finished products into a moulded and cured tyre, comprising:
• (a) introducing said initial components into a tyre manufacturing operation;
• (b) manufacturing said semi-finished products starting from one or more of said initial components;
• (c) building a green tyre starting from one or more of said semi-finished products;
• and
• (d) moulding and curing said green tyre;
• wherein said processing includes:
• detecting an initial parameter relative to said initial components, said initial parameter being a date of use of an elastomeric material for ply rubberizing;
• assigning to said initial parameter a quality index corresponding to one of a discard level, an acceptable level, and an acceptable level with reserve, the assignment comprising comparing said initial parameter with a discard threshold and a reserve threshold for the initial parameter, wherein said discard threshold for the initial parameter separates the discard level from the acceptable level and wherein said reserve threshold for the initial parameter corresponds to the acceptable level and defines one or more acceptable levels with reserve proximal to the discard threshold;
• at said processing step b), wherein the quality index of the initial parameter corresponds to an acceptable level with reserve, detecting a further parameter relative to said semi-finished products, said further parameter being a concentration of air bubbles of a rubberized ply, and assigning a subsequent quality index to said further parameter, said subsequent quality index being assigned by comparing said further parameter with a discard threshold and a reserve threshold for the further parameter, wherein said discard threshold for the further parameter separates a discard level from an acceptable level for the further parameter and wherein said reserve threshold for the further parameter corresponds to the acceptable level for the further parameter and defines one or more acceptable levels with reserve for the further parameter proximal to the discard threshold for the further parameter;
• discarding said rubberized ply when said subsequent quality index corresponding to said discard level is assigned to said further parameter;
• feedbacking from the processing step b) the assignment of said subsequent quality index in order to verify the quality index of said initial parameter and the subsequent quality index of said further parameter;
• and
• modifying at least one of the quality index of said initial parameter and the subsequent quality index of said further parameter by said feedbacking so as to be assigned with the quality index corresponding to said acceptable level at a subsequent control.