| Air Spray Line | Compressed air atomizes liquid paint into a fine spray. The operator or automatic reciprocator controls the spray pattern and coating thickness. | Waterborne, solvent-borne, two-component and clear coatings. | Atomizing air commonly 1.5–4 bar; coating thickness often 15–50 μm per coat. | Complex metal parts, plastic components, furniture, machinery and products requiring a high-quality appearance. | Excellent finish quality, flexible color changes and good control on irregular surfaces. | Overspray can be high; booth ventilation, paint filtration and operator training are important. |
| Airless Spray Line | A high-pressure pump forces coating through a small orifice, breaking it into droplets without compressed-air atomization. | High-build primers, protective coatings, acrylics, epoxies and polyurethanes. | Fluid pressure commonly 70–250 bar; suitable for medium-to-high film build. | Large steel structures, agricultural equipment, containers, tanks and heavy industrial parts. | Fast application, high productivity and good coverage with thick coatings. | Less forgiving on small or intricate parts; overspray and surface texture require process control. |
| Electrostatic Liquid Spray Line | The paint droplets receive an electrical charge and are attracted to a grounded workpiece, improving wraparound deposition. | Solvent-borne and waterborne liquid paints formulated for electrostatic application. | Typical transfer efficiency is approximately 60–90%, depending on part geometry and settings. | Automotive components, appliances, metal furniture, cabinets and repeated production parts. | Reduced overspray, strong edge coverage and consistent finish on conductive parts. | Requires electrical grounding and controlled booth conditions; recessed areas may receive less coating. |
| Powder Coating Line | Dry powder is electrostatically charged and sprayed onto a grounded part, then melted and cross-linked in an oven. | Thermoset epoxy, polyester and epoxy-polyester powders; thermoplastic powders for selected uses. | Typical metal part curing is about 160–200°C object temperature for approximately 10–30 minutes, depending on formulation. | Metal panels, frames, appliances, wheels, shelving and outdoor equipment. | Very low volatile organic compound emissions, high durability and reclaimable overspray in suitable systems. | Requires an oven and electrically conductive parts; heat-sensitive substrates are generally unsuitable. |
| Dip and Immersion Line | Parts are immersed in a tank so the coating contacts external and internal surfaces. Electrodeposition adds an electric field to drive charged particles onto the part. | Waterborne primers, electrophoretic coatings, rust-preventive treatments and sealers. | Tank temperature, immersion time and electrical conditions are selected according to the coating system; electrodeposition commonly uses tens to hundreds of volts. | Automotive bodies and components, fasteners, tubular parts and products with enclosed or difficult-to-spray areas. | Uniform coverage, strong penetration into cavities and high automation potential. | Large tanks, wastewater management and bath maintenance increase installation complexity. |
| Curtain Coating Line | A continuous falling curtain of liquid coating is formed across the conveyor width; flat panels pass through the curtain at a controlled speed. | Waterborne lacquers, UV-curable coatings, primers and clear finishes. | Commonly used for flat panels at approximately 10–60 m/min, depending on coating and line design. | Wood panels, doors, flooring, furniture boards and other flat products. | High throughput, even coverage and efficient coating recovery on suitable products. | Not suitable for highly contoured parts, vertical surfaces or products with complex recesses. |
| Roller and Coil Coating Line | Metering rollers transfer a controlled liquid film to a moving sheet or panel. Coil systems continuously clean, treat, coat, cure and rewind metal strip. | Polyester, polyurethane, plastisol, epoxy and waterborne coil coatings. | Continuous lines may operate from roughly 30–150 m/min; film thickness is controlled by roller gap and line speed. | Pre-painted steel and aluminum, appliances, roofing, wall panels and flat furniture components. | Very high productivity, accurate film control and low overspray. | Primarily designed for continuous flat substrates; edge and surface preparation control are critical. |
| UV-Curing Painting Line | Ultraviolet radiation rapidly polymerizes photoreactive components in the coating after application by spray, roller or curtain methods. | UV-curable acrylates, clear coats, primers and selected pigmented coatings. | Curing can occur in seconds, subject to lamp energy, coating thickness, pigment level and line speed. | Wood panels, flooring, printed surfaces, electronics and products requiring rapid handling. | Very fast curing, high productivity and limited thermal exposure to the substrate. | Shadowed areas may remain uncured; lamp maintenance, shielding and photoinitiator compatibility are necessary. |