Method for harmonising colour in manufactured items

A 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) generating an identification for each vehicle part to be manufactured;
• b) determining for each of the identified vehicle parts, the manufacturing elements and processes that are directly related to the end color result of the manufacturing process such as but not limited to:
• injection molds for injection processes, extrusion dies and rollers for extrusion processes;
• c) 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) specifying 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, such as but not limited to:
• production and operation conditions of the production equipment;
• e) specifying the raw material used in the approved manufacturing route for the manufacturing of each identified vehicle part and its origin, and adding said information to the approved manufacturing route, wherein origin refers to knowing which supplier or group of suppliers, in the case of parts manufactured with a combination of two or more raw materials will be who provides the raw material in that approved manufacturing route;
• f) providing 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 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) providing tolerances for aspects of the raw materials in non-color related aspects such as but not limited to:
• ranges of viscosity and covering power of the paint;
• h) determining for each identified vehicle part, their production history comprising information such as but not limited to:
• 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) registering for each identified vehicle part its production history;
• j) carrying out a traceability method which 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) determining 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) obtaining 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) identifying the identified 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 I), 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) visually examining the identified vehicle parts identified in step m) and approving the color of said identified vehicle parts that:
• are in accordance to a controlled physical pattern that indicates the color that must be perceived in order to obtain approval by a client who will accept the parts and which is obtained by means of visual comparison performed by an expert or other means,
• and whose visual examination value is within the range representative on the sense of the acceptance of the color or rather the rejection of the part's color, wherein the visual examination can be done by a previously determined capable person or by a machine;
• o) adjusting the numerical-visual color tolerances for a particular identified vehicle part in accordance with color values obtained using technological equipment from the parts approved in step n), thereby adjusting the numerical-visual tolerances, considering the visual criteria of the client who will accept the parts;
• and
• p) 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 vehicle parts approved in step n) and accordingly adjusting the numerical-visual color tolerances that must be specified to the suppliers of raw material ensuring that applied to the approved manufacturing route result in the supplier's final authorization of the parts.

A method for the color harmonization of two or more parts that will be integrated into a finished product, comprising:

• a) for each finished product to be assembled, whose parts require to be observed in visual harmony, registering information for assembly project or “project”, including but not limited to the following information:
• project code, information of the article to assemble, information for each part that it is made up of;
• b) generating “harmonious relationships”, which includes determining the relationships between two or more parts whose colors must be in visual harmony with each other, situation usually related with the closeness or physical proximity in the finished product, and additionally, which area of each part of each harmonious relationship must be related with the measurement area of the rest of the parts that integrate the harmonious relationship and finally, what supplier provides each part;
• c) registering all the harmonious relationships for each project, registering supplier information for each part, and establishing the harmonious relationships in which each supplier participates;
• d) establishing a numerical phase-shift indicator for each harmonious relationship, whose objective is to identify which parts will be assembled together by the final assembler in accordance with the sequence in which they are received by the manufacturer, following a FIFO system;
• e) for each one of the parts that integrate each harmonious relationship, providing numerical color values that are directly related to the visual resemblance of the parts with a master or controlled pattern, and on a predefined scale;
• f) continuously comparing the numerical color values for the interrelated parts of each harmonious relationship in order to verify the status of each harmonious relationship and with it identify whether there are harmonious relationships close to the unacceptable levels on a predetermined numerical-visual scale, by means of relative comparison and not just with regards to the mater or controlled pattern, taking into consideration the numerical phase-shift indicator as an indicator of the order in which the parts of a harmonious relationship will be compared.