What is the process principle of electrostatic spraying machine? How should it be operated? Next tianchang jinling electronics co., LTD. For you to introduce.
Spray the powder coating onto the surface of the workpiece with electrostatic powder spraying equipment. Under the action of electrostatic charge, the powder will be evenly adsorbed on the surface of the workpiece to form a powdery coating. Powder coating after high temperature baking leveling solidification into different effects of the final coating; Spraying effect in mechanical strength, adhesion, corrosion resistance, aging resistance and other aspects better than spray painting process.
A. Surface preparation.
The quality of pretreatment process directly affects the quality of the powder coating, and the poor pretreatment results in easy falling off of the coating and bubbling. Therefore, the pretreatment must be paid attention to.
(1) for sheet metal stamping parts can be used chemical pretreatment. Namely: remove oil → remove rust → clean → phosphating (or purification) and so on. Most of the rust or thick surface of the workpiece, the use of sandblasting, shot blasting and other mechanical methods to remove rust, but after mechanical rust should ensure that the workpiece surface clean, no dirt.
(2) blow putty. Scratch conductive putty according to the degree of workpiece defects, dry with sandpaper grinding smooth, the next process can be carried out.
(3) protection (also known as masking). If some parts of the workpiece is not required to have a coating, before the preheating can be used to cover up the protective adhesive, in order to avoid spraying paint.
(4) preheat. Do not need to warm up normally. If the coating is required to be thicker, the workpiece can be preheated to 100 ~ 160℃, which can increase the coating thickness.
The workpiece enters the spray gun position in the spray room through the conveyor chain to prepare for spraying operations. The electrostatic generator releases high voltage static electricity (negative) into the space in the direction of the workpiece through the electrode needle in the nozzle, which ionizes the mixture of powder and compressed air ejected from the nozzle and the air around the electrode (with negative charge). The workpiece passes through the hanger and is connected to the ground (ground electrode) by conveying. In this way, an electric field powder is formed between the spray gun and the workpiece. Under the double push of electric field force and compressed air pressure, it reaches the workpiece surface and forms a uniform coating on the workpiece surface by electrostatic attraction.
3. Baking and curing:
After spraying the workpiece through the conveyor chain into 180 ~ 200℃ oven heating, and the corresponding time of heat preservation (15-20 minutes) to melt, leveling, curing, so as to get the workpiece surface effect we want. Different powders vary in baking temperature and time. This is in the curing process should be noted.
Four. Clean up.
After curing the coating, remove the protection and smooth the burr.
After curing the workpiece, the daily main inspection appearance (whether smooth and bright, no particles, shrinkage cavity and other defects) and thickness (controlled in 55 ~ 90 microns). Repair or re-spray the workpiece which is found to have defects such as leakage, pinhole, bruising and air bubble.
Six. Packaging: after inspection, the finished products are classified and placed in transportation vehicles and circulation boxes, separated from each other with foam paper, bubble film and other soft packaging buffer materials to prevent scratches and wear (packaging can be based on customer requirements).
Through the above introduction hope to increase everyone's understanding and understanding of this, to bring you help.