Reason analysis: On site investigation, users used different batches of metal paint rolls (February, June, August) for the same wall.
2. Install in any direction, resulting in color difference:
Case: A user processed a 750 wall panel with polyester metal paint, silver gray 510 color rolls, and found significant color difference after installation.
After adjustment:
Before adjustment:
Cause analysis: According to on-site investigation, the wall profiled steel plates do not have male or female edges and can be installed in reverse at will. The reason for the visual color difference of the wall panels is that the installation direction of the wall panels is inconsistent.
3. The same batch of contracts are not continuously produced:
Case: A certain user used polyester metal paint Baosteel Silver 509 color roll to process PU board on the wall of a project, and after installation, significant color difference was found.
Cause analysis: The steel factory shut down the contract twice due to surface defects, resulting in the contract being divided into three production stages.
Summary of the use of metal paint rolls:
1. Design: When users have high requirements for visual color difference, metal paint rolls should not be used for polyhedral structures or buildings with angular deviations on the same plane.
2. Production: In addition to selecting color rolls from the same manufacturer, steel grade, and coating type for the same project, manufacturers also need to select raw materials from the same batch, coatings from the same batch, and production during the same continuous time period (production during the same continuous time period requires that the relevant parameters of the coating head cannot be adjusted to prevent changes in the distribution pattern of metal particles in the coating and color differences). Baosteel Huangshi Company aims to improve color difference control standards (reduce the fluctuation range of color difference values) in internal control for metal paint production and delivery, and strives to reduce the impact of subsequent processing on color difference.
3. Construction: Due to the optical properties of metal coatings, in order to prevent visual color difference, the uncoiling direction should be fixed during processing. During installation, each board (especially a single board) should have a uniform direction to avoid mixing and reversing different directions of color boards. For the same wall panel, if there are strict requirements for color difference, the processed panel shape and structure should be consistent, and the installation angle should be kept close to the same.
