Oil removal treatment of painted workpieces

Oil removal treatment of painted workpieces

Oil removal treatment is a pre pickling process, as oil is often not soaked by pickling, which can affect the pickling effect. When there is oil on the workpiece, a preliminary degreasing process is required. So what are the methods for removing oil?

1. Organic solvent degreasing

Organic solvents refer to organic solvents that have strong solubility, good volatility, low toxicity, low price, and no corrosiveness to workpieces in plant or animal oils, including benzene, lipids, chlorine containing and other organic solvents. Use organic solvents to remove oil from the surface of the workpiece to be coated. Guangzhou WLD equipment co.ltd is a professional suppliers and manufacturer of powder coating booths and lines in Guangzhou,China.

2. Chemical degreasing

Chemical degreasing is generally carried out by alkaline solution. The main component of alkaline solution is sodium hydroxide, and in most cases, sodium carbonate, sodium silicate, sodium phosphate, etc. are also added. Alkali based degreasing is more suitable for animal and vegetable oils, while for mineral oils, surface active agents such as wetting agents and detergents can be added to the solution to improve the degreasing effect. Surfactants are compounds composed of hydrophilic and oleophilic groups, which can adsorb at the interface where oil and water repel each other, thereby reducing the need for cold or hot water cleaning of workpieces after chemical degreasing to remove residual alkali and surfactants. Water washing should use flowing clean water, and place the workpiece up and down until harmful substances are removed.

3. Electrochemical degreasing method

Place the workpiece in the negative or positive direction of the oil removal wave and apply electricity for a short period of time to reduce the surface tension of the oil and reduce the surface tension. At the same time, bubbles will form on the electricity, breaking the oil film and causing it to turn into oil droplets and fall off, in order to achieve the purpose of oil removal.