Aluminum wheel coating line process design 1 process design analysis 1.1 coating process mode The use of aluminum alloy wheels in large quantities today, according to the different requirements of the product, using different methods. The current development trend of the main aluminum wheel hubs in the world is painting hubs, bright-surfaced hubs, polishing hubs, and plating hubs. The main coating modes are as follows:
1) Low-end product pre-treatment → Metallic paint coating → Finishing varnish coating 2) Mid-range product pretreatment → base Powder Coating
→ metallic paint coating → varnish coating 3) High-end product pretreatment → base powder coating Equipment → Metallic Coating → Coating → Light Powder Coating 1.2 Mechanized Conveying Modes The internationally popular aluminum hub transportation method generally adopts two types, ie, ordinary type suspension conveyor and ordinary annular ground conveyor. In the middle, the robots must be used in large quantities and the small batches must be manually.
1) Ordinary suspension conveyor is suitable for painting or dusting, and automatic spraying can ensure the quality of product spraying. The process layout is flexible and convenient. Drying can be done with multiple-stroke drying chambers, or a drying chamber where the hubs run in parallel rows.
2) Ordinary annular ground conveyor is suitable for pre-treatment cleaning process, and 2-3 workpieces can be hung according to different output, and the cleaning effect is good. The spreader is simple and suitable.
1.3 Process Layout Features As with the body coating line, the aluminum hub coating line also uses a regional approach to ensure the different levels of cleanliness needed in each area of the coating shop. Generally, spray booths and powder spray booths should be arranged in the same area. Drying chambers should be arranged in the same area. Drying chambers should be multi-stroke drying. Such an arrangement of aluminum hub painting workshops is conducive to production organization, management, and line-to-line conversion.
2 Introduction to the main process 2.1 Pre-treatment process 1) Processes According to the different products, 9-sequence or 13-sequence processes can be used, all of which use spray treatment. The details are as follows: Pre-degreasing → Degreasing → Washing → Washing → Excluding oxide film treatment → Removing oxide film treatment → DI water wash → DI water wash → DI water wash → titanium/zirconium treatment → DI water wash → Chromium-free passivation → DI water wash → moisture drying →Cooling 2) Process The pre-degreasing and degreasing process is mainly responsible for removing oil on the surface of the workpiece; the purpose of pickling is to remove the oxide on the surface of the workpiece; the purpose of passivation is to regenerate a dense oxide film on the surface of the workpiece.
2.2 Powder spraying and painting process 1) Powder spraying process Base powder spraying and glitter powder spraying can be used according to the different requirements of the product. Spraying is generally electrostatic spraying in the dusting room. When the workpiece reaches the spray station, it starts to rotate and the paint is sprayed from the positioned automatic spray gun to complete the spraying work. Powder spraying equipment (spraying equipment) purchase complete sets of equipment with high voltage electrostatic generator and paint recovery device. An electrostatic precipitator (automated electrostatic precipitator sprays air from 12 nozzles) is required before spraying to ensure the quality of the product.
2) Spray painting process Some products use spray painting process after spraying the bottom powder. Spray booths can be water-rotated or water curtain structures. Before the painting, an electrostatic precipitator (automatic dust-free electrostatic spray from 12 nozzles) is required to ensure the quality of the product. Spray painting or dusting are all automatically sprayed and the workpiece can be raised, rotated, etc. in the spray booth or dusting chamber.
3 Some points worthy of attention 3.1 Selection of coating equipment 1) Pretreatment equipment The pretreatment equipment adopts full spray clea