Spraying Process Requirements for Jerrys Intelligent Robot Imported Spray Guns

JERRYS ROBOT

1. If the workpiece is not corroded and does not require pickling, silane treatment can be used, which is more environmentally friendly compared to phosphating.

2. If the salt spray time requirement is not very strict, a simple four-in-one treatment method can also be used, which has lower costs.

3. However, regardless of the treatment method, the powder coating base layer must be free of oil and rust. The specific process depends on the quality of the incoming parts. If the quality is poor, with heavy oil and severe rust, the traditional process of degreasing - rinsing - pickling - rinsing - rinsing - surface conditioning - phosphating should still be used.

Compared to traditional spray painting processes, electrostatic powder coating offers significant advantages: no need for thinners, environmentally friendly construction with no pollution, non-toxic to humans; excellent coating appearance quality, strong adhesion and mechanical strength; short curing time for sprayed coatings; much higher corrosion and wear resistance; no primer required; simple construction with low technical requirements for workers; lower cost than spray painting; some construction sites explicitly require the use of electrostatic powder coating; no dripping phenomenon commonly seen in spray painting processes during electrostatic powder spraying.

The basic principles are as follows:

1. A high-voltage corona discharge field is formed between the spray gun and the workpiece. When powder particles are sprayed out from the gun nozzle and pass through the discharge area, they capture a large number of electrons and become negatively charged particles. Under electrostatic attraction, they are adsorbed onto the positively charged workpiece.

2. When the powder adheres to a certain thickness, the "like charges repel" effect occurs, preventing further powder adsorption. This ensures uniform powder layer thickness across all parts. After heating and baking for curing, the powder layer levels to form a uniform film.

The quality of the pre-treatment process directly affects the quality of the powder coating film. Poor pre-treatment can lead to issues such as coating peeling and blistering. Therefore, pre-treatment must be taken seriously.

For sheet metal stampings, chemical pre-treatment methods can be used, such as: degreasing → derusting → cleaning → phosphating (or passivation). For workpieces with severe rust or thick surfaces, mechanical methods like sandblasting or shot blasting can be used for derusting. However, after mechanical derusting, the workpiece surface must be ensured to be clean and free of scale.

Apply filler. Depending on the degree of defects in the workpiece, conductive filler is applied. After drying, sand it smooth to proceed to the next step.

Protection (also known as masking). If certain areas of the workpiece do not require coating, they can be covered with protective tape before preheating to avoid coating.

Preheating. Generally, preheating is not required. If a thicker coating is desired, the workpiece can be preheated to 100–160°C to increase the coating thickness.