Glossary

Camber - Camber is the deviation of straightness of a strip edge from a straight line. The measurement of the level of camber is taken on the concave side, using a straight edge. Long lengths of unsupported strip having a large amount of camber can deviate from the horizontal or slope to one side.

Center Stretch (Full Center) - A phenomenon whereby the center of the strip is longer than the edges, so that the strip is not flat. See Oil Can.

Chatter - Transverse perpendicular rows of varying film thickness on the painted strip. The marks are usually due to vibration of the coating rolls, strip or to an eccentric roller.

Cleaning Section - The portion of the coil coating process where the strip is prepared for painting. This process can include High Pressure Washers, Mechanical Scotch Brite brushes, Alkaline Spray cleaning and Hot water rinsing. This section is designed to remove “tramp” oils from the strip surface. Air knives are utilized to dry the strip prior to painting.

Coating - A layer of some paint material covering the strip surface.

Coater (or Roll Coater) - An apparatus that applies a paint coating to the metal strip surface. The coater apparatus consists of rolls, which support the strip through the apparatus while at the same time are able to pick up, meter and deposit the paint coating onto the moving strip

Color - This is a visual and numeric comparative to a prescribed, precise shade. It is typically referred to as a color standard. A complete color definition includes a coated metal panel that depicts all of the deviations from the prescribed color.

Cratering - A coating defect related to surface tension. It is characterized by small pockmarks or indentures surrounded by a ring of coating material projected above the general plane of the coating. In severe instances, the area in the center of the crater may show the substrate. Craters are typically caused by contamination of the surface.

Curing Oven - The unit where Peak Metal Temperature is achieved and maintained momentarily to cure the organic coating. This unit typically has multiple zones with individual controls for temperature. The strip hangs in the oven between catenary points.

Direct Coating - A method for applying a film of material with a coating roll that revolves in the same direction as the travel of the strip. This is also referred to as forward coating.

Drawability - The amount of elasticity to allow for stretching of the metal and/or coating.

Durometer Hardness Tester - An instrument for the determination of hardness of elastomers or other compressible rubber-like materials, commonly used for hardness measurement of roll coverings and heavy film of plastic (e.g. plastisols) . Test results are displayed as a percentage of scale deflection from 0 to 100 for any given scale employed. (Most commonly used: scale “A”).

Entry Section - This refers to the area where material is loaded on to the paint line. The entry section includes a shear for squaring the lead edge of the strip or to remove minimal damage of the coil O.D. and either a welder or mechanical stitcher that links coils together for continuous processing.

Flexibility - The degree to which a coating can withstand deformation without significant change in the coated surface integrity for cracking, crazing, color and gloss.

Flow - The property of a paint that manifests itself in the degree of leveling or in an ability to flow or move under applied stress.

Gloss - The luster shininess or reflecting ability of a surface.

Gloss Meter - An instrument for measuring floss usually at 60 or 20 degrees from the vertical.

Hardness Pencil - A method to determine the hardness of a paint film. Each of a series of drawing pencils calibrated for hardness is sanded to a blunt point and then held at a 45-degree angle and pushed forward and downward against the panel to be tested. The hardness designation of the pencil, which just fails to cut the film, is the pencil hardness of the film.

Hot Rolled Steel – A metal substrate consisting of plain carbon steel that is typically soft (annealed) and does not have any metallic coating.

Leveler or Roller Levelers - An apparatus containing a series of steel rolls, which flatten or level a metal strip as it passes between the rolls.

Micrometer - An instrument used for mechanically measuring the dry film thickness of paints or the thickness of a metal strip.

Mil - A unit of measuring thickness: 0.001 inch. Generally used to describe the paint film thickness.

Oil Can - A localized out-of-flat condition often seen as buckles toward the center of an otherwise flat strip.

Organic Coating - A liquid, which, when applied, dries and/or cures into thin, solid, functional film. Applications are commonly intended for industrial use. May be clear or pigmented.

Paint - In the sense of roller coater application, the term paint is used to denote a liquid composition, which is converted to a solid film after application as a thin layer. Usually the liquid will be pigmented.

Pan - An open container at a roller coater which holds the paint, conversion coating or other liquids and within which the pick-up roll revolves.

Pick-Off - Tendency of paint to be picked up in very small pieces from one side of a painted strip and held by the coating on an adjacent wrap of the strip. It also can refer to transfer of coating material to tension and bridle roll.

Pick-Up Roll - A roll revolving within the pan and is partially submerged in the paint conversion coating or other liquids. The pick-up roll picks up paint from the pan and applies it to the transfer or applicator roll.

Pigments - There are two forms of pigments in organic coating, both of which are in a powder form in the virgin state. One form is a coloring substance to achieve a specified color hide. The second is a controlling substance for gloss control. Pigments can be specified as an interior grade or as an exterior grade for corrosion/ultraviolet protection.

Pits -Very small craters.

Popping - A defect in a paint film usually caused by organic solvents trapped during the curing of the film: fine blistering.

Pressure Marking or Mottling or Streaking - An uneven pattern often seen as glossy spots, which are usually caused by pressures within a painted coil. These become visible during the uncoiling process

Quench - The heated, cured strip is water quenched by spraying. The quench tank water itself is quenched by re-circulating through cooling towers..

Recoiler - The apparatus used to recoil the strip after it is painted.

Reverse coating - Coating with the coating roll revolving in the direction opposite to that of the strip.

Roll former - An apparatus that forms a continuous strip of painted metal into various shapes by a series of revolving metal wheels or rolls.

Shear - The viscous force acting parallel to the strip at the point where the applicator roll meets the strip on a roller coater. Shear also occurs at all roll-to-roll contact points. Can also refer to metal cutting equipment.