How to solve the shrinkage hole in the spray line during the spraying process?

The surface shrinkage of the spray equipment during the coating process has both substrate reasons, pretreatment, chrome contamination, powder coating, compressed air and management. It should be targeted at different shrinkage. Holes, find the cause, take different solutions, and establish preventive mechanisms to reduce or avoid the occurrence of shrinkage cavities. Our company is equipped with advanced fast color changing powder supply center. The color change time only takes 10-15 minutes, which can save a lot of powder replacement time and fundamentally solve the shrinkage phenomenon caused by mixing powder.

In today’s coating equipment factory, there are always some unavoidable problems in the process of spraying spray line. The new moon is coated for 25 years of professional manufacturing. For these details but important issues, today’s new moon coating is available. Explain why the shrinkage hole is generated during the spraying process. Let us first analyze what is the “shrinkage hole”? As the name suggests, “shrinkage” refers to the presence of impurities (or foreign matter mixed into the paint, such as water, oil, etc.) on the sprayed surface. The paint cannot adhere to the surface evenly, causing shrinkage to expose the coated surface, showing a circular hole. It is called “shrinkage hole”.

The causes of shrinkage cavities are various, that is, there are substrate reasons, as well as pretreatment, powder and management reasons, such as pre-treatment degreasing is not complete; compressed air quality is unqualified, powder supply gas and atomizing gas contain

Oil; resin is not compatible with shrinkage caused by mixing powder…

First, the pre-treatment is not complete

Reason: The quality of the pre-treatment will lead to the appearance of shrinkage cavities after painting. For the pre-treatment only, the formation of shrinkage cavities is not caused by degreasing, and it is also related to phosphating and coating.

Solution: Adjust the degreasing process to ensure that the profile is clean and degreased. The degreasing quality is evaluated mainly by the fact that the surface of the workpiece after degreasing cannot have visual grease or emulsion.

Pre-processing equipment

Second, the compressed air quality is unqualified

Reason: The air with water or oil will spray on the workpiece with the paint. After the coating, there will be a water hole leaking at the bottom, that is, the surface shrinkage caused by water or oil.

Solution: Check the compressed air quality and the operation of the dewatering and degreasing equipment, discharge the compressed air condensate and oil in time, and clean the air line together.

Air compression system

Third, the chain under the oil pan pollution

Cause: The oil pan under the chain is deformed, causing contamination of the chain dripping oil.

Solution: Check the oil usage of the chain and check the oil pan of the chain to avoid contamination.

Chain conveyor system

Fourth, powder coating is not compatible

Reason: The incompatibility of the resin in the powder coating composition is the main cause of the formation of shrinkage cavities. In the process of using the powder coating, the choice of the formulation body and the resin of each spray manufacturer cannot be mixed.

Solution: Try to use the manufacturer to order the coating according to the total amount of spraying, concentrate the use of batch powder coating, avoid mixing of different batches of powder coating as much as possible, and then change the color after fine cleaning after use. Clean powder tube and dusting system.

Curing heating system (5)