Common defects and treatment methods of UV coating surface

1. Common defects: uneven thickness of the coating film

Defect concept: refers to the uneven coating amount on the left and right sides of the workpiece

Causes:1. The left and right sides of the knife edge are unbalanced

2. The knife edge is worn

Solution: Adjust the knife edge so that it is balanced left and right, remove the blade and grind

2. Common defects: irregular coating curtains

Defect concept: Refers to the fact that the curtain does not appear to be a flat surface

Causes:1. The knife edge is blocked or worn

2. Clogged by debris

Solution: Remove the blade and grind to remove the impurities

3. Common defects: unstable coating curtain and broken film

Defect concept: refers to the irregular tearing of the painted curtain

Causes:1. Clogged with debris

2. The paint flow adjustment is too small

3. Improper gap between the knife edges of the curtain

4. The viscosity of the paint is too low, and the paint temperature control is too high

5. The paint is contaminated

6. Factors of the paint itself

Treatment method: 1. Remove impurities

2. Increase the flow rate appropriately

3. Adjust the knife edge clearance

4. Increase the viscosity of the paint and reduce the paint temperature appropriately

5. Replace the paint

6. Check the paint formula

4. Common defects: small black spots and holes on the surface of the paint film

Defect concept: refers to the phenomenon of pinholes or small bubbles and dust spots on the surface of the paint film

Causes:1. The bottom plate is dusted cleanly

2. The back cover is not tight

3. Over-sanding

Solution:1. Dust thoroughly

2. Re-cover the back cover

3. Strictly control the grinding

5. Common defects: the surface of the paint film is uneven

Defect concept: refers to the surface of the paint film is not smooth and rough

Causes:1. The primer is sanded unevenly

2. Poor leveling of the coating

Solution:1. The primer is thoroughly sanded and smoothed

2. Heating and leveling or extending the leveling time appropriately

6. Common defects: there are shrinkage porosity on the surface of the coating film

Defect concept: refers to the phenomenon that the surface of the paint film presents small circular pits of different sizes and distributions

Causes:1. The paint itself is not compatible

2. The paint is adulterated with incompatibilities

3. The surface treatment of the work object is not clean

Solution:1. Review of paints

2. Pay attention to the operation and avoid entering the washing machine or other incompatible substances

3. Clean the surface of the workpiece

7. Common defects: uneven gloss

Causes:1. Stir unevenly

2. The reverse transmission speed of the curing machine is uneven

Solution:1. Stir well before use

2. Control the uniform curing rate of miscellaneous materials