[L1] 1 Overview [L2] 1) Purpose of Painting [L4] - A means for the semi-finished paint to form a solid coating film, the finished product. [L4] - Film formation contributes to maintaining the lifespan of the object, grants a beautiful appearance, and provides specific functions. [L2] 2) Characteristics of Painting [L4] - Precautions are needed for the purpose and effect of painting. [L5] * Consideration of painting method according to the object is required. [L5] * Consideration of painting method according to the paint type is required. [L5] * Consideration of painting method according to the painting environment is required. [L1] 2 Painting Procedure [L2] 1) Equipment for Painting [L4] - Paint: Mixing room, batch. [L4] - Pre-treatment: Pre-treatment agents, pre-treatment equipment. [L4] - Painting Equipment: Painting devices (Spray, Air), Booth. [L4] - Drying Equipment: Hot air drying oven, Infrared drying oven. [L4] - Quality Control: Viscometer, film thickness gauge, color difference meter, etc. [L2] 2) Painting Process [L3] ① Pre-treatment: Wipe off dust and foreign substances to keep the surface clean. Perform surface treatment such as polishing or chemical treatment if necessary. [L4] - Physical Polishing: Hand tool cleaning, Power tool cleaning, Blast cleaning (Method of removing rust and foreign substances on the surface by spraying sand or iron particles). [L4] - Chemical Polishing: Solvent degreasing, Alkali degreasing (using surfactants, etc.), Emulsion degreasing, Vapor degreasing. [L4] - Acid Cleaning (Pickling): Method of removing rust and mill scale on the surface using various acids. [L5] * Mill Scale: An oxide film layer formed on the steel surface when mild steel is heated to 570~1370℃ or rolled below 570℃. [L4] - Chemical Conversion Treatment: Generating stable compounds on the metal surface, including phosphate treatment, blackening treatment, chromate treatment, etc. [L3] ② Paint Mixing: Mix appropriately according to product characteristics and paint characteristics. Mix through the recommended hardener. [L3] ③ Painting: Apply paint to the surface to be painted. [L3] ④ Drying: Dry the painted surface to create a coating film. [L3] ⑤ Polishing: Polish with abrasives to smooth the painted surface. [L3] ⑥ Re-painting: Paint repeatedly to form the targeted coating film. [L1] 3 Types of Painting and Quality Control [L2] 1) Painting Methods [L4] - Brush Painting [L4] - Roller Painting [L4] - Spatula Painting [L4] - Air Spray: Method of spraying paint using compressed air. [L4] - Airless Spray: Method of atomizing paint through a nozzle for spraying. Uses high-pressure piston pumps, applied to large and flat objects like ship steel bridges. [L4] - Powder Coating: Method of spraying paint in powder form. Coating with solids without using organic solvents or water. [L4] - Electrostatic Painting: Method using static electricity. Paint is negatively (-) charged and adsorbed onto the grounded object (+). [L4] - Electrodeposition Painting: Method of immersing the object in electrodeposition paint and electrically depositing a film on the object's surface through current. [L4] - Dip Painting: Method of immersing the article in paint and drying it. Also called Dipping. [L2] 2) Painting Quality Control (Inspection Instruments) [L4] - Surface Roughness Tester [L4] - Film Thickness Gauge [L4] - Color Difference Meter [L4] - Gloss Meter [L4] - Viscometer, Viscosity Cup