Process design of coating equipment coating pretreatment production line

Process design of coating equipment coating pretreatment production line

The pre-coating treatment of coating equipment includes three parts: degreasing (degreasing (degreasing removal), rust removal and phosphating. Phosphating is the central link, oil removal and rust removal is the preparation process before phosphating, so in production practice, it is necessary to take phosphating work as the focus, but also to start from the requirements of phosphating quality, grasp the oil removal and rust removal work, especially pay attention to the interaction between them. According to the oil, rust degree and primer requirements of the workpiece, the pre-coating production line can be divided into different processes.

1. Rust-free workpiece

Pre-degreasing - degreasing - water cleaning - surface regulation - phosphating - water cleaning - drying (electrophoretic primer can not be dried and directly into the electrophoresis tank). This is a standard four-station process, with a wide range of applications, suitable for all kinds of cold-rolled plates and machined rust-free workpiece pretreatment, and can also add the surface adjustment agent to the degreasing tank to reduce a surface adjustment process.

2. General oil, rust, oxide scale mixed workpiece

Degreasing and rust removal "two-in-one" - water cleaning - neutralization - surface adjustment - phosphating - water cleaning - drying (or direct electrophoresis). This set of process is a widely used process in China, suitable for the pretreatment of all kinds of workpieces (except heavy oil pollution); If medium temperature phosphating is used, the surface adjustment process can also be omitted, and the simple plate workpiece can also be eliminated from the neutralization process, becoming a standard four-station process with rusted parts.

3. Heavy oil stain, rust, oxide scale workpieces

Pre-degreasing - water cleaning - degreasing and rust removal "two-in-one" - water cleaning - neutralization - surface adjustment - phosphating - water cleaning - drying (or directly into the electrophoresis tank). For heavy oil-stained workpieces, pre-degreasing should be carried out to remove most of the grease to obtain a clean metal surface after the "two-in-one" treatment of degreasing and rust removal in the next step.

Remaining on the surface of the workpiece oil, rust, etc. will seriously hinder the growth of phosphating film, therefore, oil removal and rust removal are two basic and important processes before phosphating, relatively speaking, oil is more harmful than rust, and the workpiece with oil directly affects the rust removal speed, so rust removal should be carried out on the basis of oil removal. The phosphating film is formed only on the surface of the workpiece that has removed foreign matter such as oil, rust, and oxide scale.

Coating equipment In the process design of the pre-coating treatment production line there are some matters to pay attention to, if not considered, will have a lot of adverse effects on the operation of the production line and worker operation, such as process interval, overflow water washing, phosphating slag removal, workpiece process holes, tank and heating tube materials. The purpose of the coating line pretreatment is to remove all foreign matter except the composition of the coated part, provide a good substrate suitable for the coating requirements, and have good corrosion resistance and adhesion of the coating. Therefore, the design process of the coating line pretreatment line is very important.