Consumers may never see the inner-workings of a product, but they surely notice the exterior’s form and finish. That’s why more and more manufacturers have moved away from unpredictable post-painting operations to the consistent quality of coated metal coils.

Today’s coil coating lines include a series of strict physical tests and visual inspections to ensure the paint is applied to the metal surface and cured properly to best perform in its end use. Before coating, the substrate and coatings are checked for the proper characteristics. During the coating process, continuous control and testing of surface treatments, paint film thickness and cure, and other critical parameters are performed. Some of the main quality control tests applied to coated coil after the coating process include:

Film thickness. The right film thickness is critical for the long-term performance of the coating. Primers and topcoats are checked for specified thickness.

Color and Gloss. Matching a color standard between each run ensures consistency of color over time. Color is checked for consistency across the width of the metal strip, from coil to coil, and between production runs, to match the color standard on record. The coating’s gloss is also measured to confirm the gloss falls within a set range for further control consistency.

Adhesion. To confirm adhesion of a coating to the substrate, “T-bends” and reverse impact tests are conducted. Tape is applied to the bend or impact area and removed to determine adhesion.

Curing. To ensure a coating is ready for extreme forming or weathering in its end use, a combination of tests are run on the coated substrate to indicate if paint has been under-cured or over-cured.

Visual Inspection. Thorough visual inspections are conducted to identify craters, differences in texture and dirt lines, and more.

To help with your end product’s quality control, specify the predictable quality of prepainted metal.

For more information about converting your manufacturing process to prepaint, contact the National Coil Coating Association at ncca@coilcoating.org or 216-241-7333.