Method for harmonising colour in manufactured items

A computer automated method for generating numerical-visual color tolerances for parts manufactured by a manufacturing process that are required to be visually similar to a controlled color pattern, a visual reference value on a predetermined scale, or to the rest of the parts along with which they will be assembled into a whole product, comprising:

• a) automatically generating an identification for each vehicle part to be manufactured;
• b) for each of the identified vehicle parts, requesting information about the manufacturing elements and processes that are directly related to the end color result of the manufacturing process comprising:
• injection molds for injection processes, extrusion dies and rollers for extrusion processes;
• c) automatically generating an approved manufacturing route which comprises defining the sequence or combination of color-affecting process and manufacturing equipment, and tools for the identified vehicle parts, and that will be used for manufacturing such parts;
• d) requesting information about critical variables for the approved manufacturing process and manufacturing equipment and tools of each identified vehicle parts whose variation has an impact on the final color of the vehicle parts thus obtained and that will be approved by the client, comprising:
• production and operation conditions of the production equipment;
• e) requesting information about the raw material used in the approved manufacturing route for the manufacturing of each identified vehicle part and its origin, and automatically adding said information to the approved manufacturing route in the database, wherein origin refers to the supplier or group of suppliers;
• f) requesting information about a controlled pattern or plate or nominative reference based on a controlled catalog of the visual appearance of color desired by the client on the identified vehicle parts, as well as requesting the client's measurement specifications, specifically the zones of each identified vehicle part that require measurement and the measurement angles in each of these zones;
• g) requesting information about tolerances for aspects of the raw materials in non-color related aspects comprising:
• ranges of viscosity and covering power of the paint;
• h) generating for each identified vehicle part, a data field containing their production history comprising information comprising:
• description of the raw material that was applied to each identified vehicle part;
• information about the lot and container the raw material comes from;
• information about the staff that was responsible for the transfer of the raw material;
• information about the staff that was responsible for the supervision and operation of the production process;
• information about the operating conditions of the production process in the approved manufacturing route for each identified vehicle part;
• times at which each identified vehicle part was at each of the specific production stages of the approved manufacturing route;
• information regarding the color of each identified vehicle part comprising a numerical examination performed using technological equipment, such as an spectrophotometer, which under equal conditions of texture and substrate gives repeatable numerical readings in a standardized measurement system;
• information about visual examination of the color of each identified vehicle part, which is performed by a previously determined capable person or machine, and which comprise values in the same standardized measurement system, taking into account the controlled pattern or plate or nominative reference for a specific identified vehicle part, such predefined values being within a predefined range representative on the sense of the acceptance or deviation of the color with respect to said controlled pattern or plate or nominative reference;
• i) automatically adding and relating the corresponding data field containing production history to the data of each identified vehicle part in the database;
• j) carrying out a traceability method which automatically registers each step as of entry of the raw material into the warehouse up to its entry into the manufacturing equipment, according to the approved manufacturing route, with the added purpose of implementing a First-In, First-Out (FIFO) identified vehicle parts manufacturing process;
• k) producing by means of the computer numerical-visual color tolerances for each part based on the numerical readings and visual examination of the color of each identified vehicle part, which comprise a range of numerical values that can be entered into technological equipment such as a spectrophotometer that ensure visual acceptance and that may be provided to suppliers of raw materials, in order to be applied to the approved manufacturing route for producing a identified vehicle part having a color within the numerical-visual tolerances;
• l) producing by means of the computer tolerance values for the critical variables for the manufacturing process defined in step d) of the approved manufacturing route and the correlations between the manufacturing process variables and the final color result, such as to identify which color variables given in a standardized format for each identified vehicle part are controllable by means of changes to the critical variables for the manufacturing process, so that the necessary corrective actions can be taken when finding deviations in the color readings of the final identified vehicle parts;
• m) automatically selecting and registering information corresponding to vehicle parts produced in accordance with the numerical-visual color tolerances obtained in step k) and with the tolerance values for the critical variables for the manufacturing process obtained in stage l), that resemble the controlled pattern or plate or nominative reference, as well as those identified vehicle parts that are visually acceptable to a client or to an expert;
• n) automatically performing a visual examination of the parts identified in the previous stage (part-color numbers) and provide a numerical evaluation in a standardized format which is automatically converted to a numerical color specification based on a custom pre-programed standardized criteria based on the perception of the client who will accept the parts, which comprises an ideal numerical color specification in accordance with a predefined numerical pattern that represents the physical color that must be perceived by a person in order to obtain approval by such person, wherein the visual examination is performed by means of a colorimeter or other computer vision system;
• o) automatically comparing the numerical color specification obtained in step n) corresponding to a part-color number with the predefined numerical pattern, and providing a numerical evaluation of color deviation resulting from the comparison and assigning the corresponding part-color number an approved status if the color deviation is within a predetermined pre-programed numerical range;
• p) automatically adjusting the numerical-visual color tolerances in the database for a corresponding part-color number in accordance with the numerical evaluation in a standardized format corresponding to the part-color number approved in stage n);
• q) automatically adjusting the tolerances of the approved manufacturing route and the correlations between the process conditions and the color end result in accordance with the numerical evaluation in a standardized format corresponding to the part-color number approved in stage n);
• r) automatically adjusting tolerances of the critical variables for the approved manufacturing route and the correlations between the approved manufacturing route operating conditions and the color end result in accordance with the color values obtained from the identified part-color number approved in step n) and accordingly adjusting the numerical-visual color tolerances that must be specified to the suppliers of raw material.