Spraying defects and treatment methods

Laminated coating defects and treatment methods

Various defects often occur in the spray coating technology during the coating process. The causes of these defects and the corresponding treatment methods are as follows:

Bubbles: causes

• Paint viscosity is too high.

• The filter of the shower coater failed.

• Paint delivery pressure is too high.

• The paint circulates in the device for too long, causing the viscosity to rise and create bubbles.

• The distance between the shower head knife edge and the surface to be painted is too large, causing the impact force to increase when the paint comes into contact with the surface.

Approach:

• Use thicker paint or add an appropriate amount of defoaming agent.

• Check and repair filter.

• Adjust paint transfer pump pressure.

• Adjust the viscosity of your paint frequently.

• Adjust the distance between the shower head blade and the surface to be coated to an appropriate range, generally 10cm.

Whitening: Causes

• Water is mixed into the solvent.

• The humidity of the construction environment is too high.

• The surface of the substrate being coated contains moisture.

• Too much low boiling point solvent was added.

Approach:

• Check the quality of the solvent.

• Control relative humidity below 80%.

• Remove moisture from the surface of the substrate being coated.

• Control the amount of low boiling point solvent added.

Broken Curtain: Causes

• Paint viscosity is too low.

• Paint pressure too low.

• There are particles in the bottom seam knife edge.

• The knife edge gap is too large and the paint delivery pressure is too small.

Approach:

• Increase the viscosity of paint.

• Increase paint pressure.

• Remove particles from the bottom seam knife edge.

• Correctly adjust the knife edge gap to control the delivery pressure of the paint.

Coating discontinuity: causes

• The wind speed in the construction site is too high.

• The ventilation above the machine head is too strong.

• The distance between the shower head blade and the surface to be painted is too large.

• The conveyor belt has jumps and transitions and there is paint on the rollers.

• Paint viscosity is too low.

Approach:

• Control wind speed in construction sites.

• Reduce ventilator power.

• Lower the height of the machine nose.

• Check the conveyor system.

• Adjust the viscosity of the paint.

Side sags and paint build-up: causes

• The amount of spray applied at one time is too thick.

• Poor levelness of conveyor belt and drying rack.

Approach:

• Control the amount of paint sprayed.

• Check the levelness of the conveyor belt and drying rack.

Understanding the causes of defects in these shower coating technologies and their corresponding treatment methods can help improve the quality of coating and ensure that the appearance and performance of the coating can meet the expected standards. With appropriate treatment methods, the impact of these defects on the painting results can be effectively reduced.