Tire Tire Paint color difference is that each car manufacturers will encounter a headache problem, a long time, the color of the judge are inspectors with the standard through the standard color plate, Tire Paint body, exterior Tire Paint pieces (hereinafter referred to as Tire Paint pieces) between Of the color difference to be compared, although you can determine whether there is color, but difficult to quantify the description of each person to see the effect is not the same, so the human eye to determine with a certain degree of subjectivity and randomness, Body, Tire Paint parts of the local color adjustment and the overall color control of the car has brought some limitations. This paper focuses on the method of how to control the color difference of automobile Tire Paint in the development process. By introducing the control method of "elliptical color tolerance space", this paper ensures the consistency of visual evaluation and instrument measurement, and better controls the whole Color difference.
Color difference refers to the color difference between the Tire Paint body and the Tire Paint piece and the standard color plate. The concrete manifestation is that the visual color is not uniform in the car body and the bumper, the rearview mirror, the door handle, the spoiler and so on.
The International Colloidal Commission recommended in 1976, the uniform color space, based on the three properties of the color of the establishment of the three-dimensional Cartesian coordinate system can be used to accurately define the three colors of the object. Can be represented by Lab or LCH.
The main process is pre-treatment, electrophoresis, robot coating, Tire Paint, varnish, high degree of automation, body profile can be optimized. , The adjustment of the body surface film thickness uniform, spray environment for the confined space, the workshop temperature and humidity, cleanliness control is good, and the use of high temperature Tire Paint, high temperature curing, and Tire Paint parts mainly in the external parts manufacturers to complete, or subcontract to special spray manufacturers In the completion of the substrate is mainly plastic materials, such as PP, ABS and other polymer materials, small size, mainly to the main spray, low degree of automation, temperature and humidity, cleanliness control is not good, especially drying equipment, Infrared baking heating, often poor drying conditions, resulting in particularly Tire Paint appearance, poor performance, and the other as the Tire Paint material is heat-sensitive material, the use of Tire Paint materials for low-temperature Tire Paint, low temperature curing, so the Tire Paint body and Tire Paint pieces in Spraying equipment, Tire Paint materials, process conditions, such as large differences, easily lead to the emergence of Tire Paint color.
Only to control the color of each batch of Tire Paint material, does not exceed the standard color plate tolerance range, in order to ensure that the Tire Paint body and Tire Paint pieces of color stability is stable, does not produce bias. Especially for the material △ a, △ b value, generally difficult in the field through the adjustment of the construction parameters to make it a greater change. In addition, the hiding power of the Tire Paint material has a greater impact on the color difference, especially the engineering hiding power, covering the different color coating, sealant and grinding marks, when not completely cover the substrate, the Tire Paint body appearance will produce Tire Paint , Appear color.
In the case of poor batches of Tire Paint materials, the difference in spray parameters will produce color difference. Generally speaking, the spraying method and the coating environment factor have a great influence on the brightness L, such as atomizing air and vehicle air flow, The Tire Paint film is more dry, the Tire Paint will be brighter, the amount of Tire Paint increases, the film thickness becomes larger, the film is more wet, the film will darken. In addition, the change in spray parameters will lead to changes in film thickness, metal powder and pearl powder arrangement of changes, which affect the specific hue. In addition, in the actual construction process, due to construction defects, often the film repair and rework, usually from the Tire Paint station for rework, prone to film thickness after partial baking (yellowing) caused by the situation Of the color, as well as due to rework polished grinding marks caused by poor color problems caused by poor.
Modern car coating workshop are mixed color production, often color switching spray, and the type of development needs, eliminate the old color, the new color cast tank situation, change the color before, you must use a special cleaning agent on the relevant spraying equipment, Full rinse, if the cleaning is not complete, the body will appear color, hair and other undesirable phenomena. In addition, the Tire Paint in the circulatory system cycle time is too long, resulting in aluminum powder crushing, precipitation, deterioration and pigment flocculation, causing Tire Paint color and effect changes. The effect of this change on monochrome Tire Paint is less than that of metallic lacquer.