Problems related to the appearance of the powder coating surface and investigating their factors

Pinholing in the powder coating

1. Complete surface preparation is not done and oil and grease remains on the surface
2. Residues of surface preparation chemicals
3. Color incompatibility with other manufacturers’ powder coatings
4. The presence of water and oil in the feed and air of the compressor
5. Rust on the surface of the piece

Outgussing and craters

1. Incompatibility with other powder coating
2. Film thickness too high
3. High humidity of powder coating
4. Gas trapping and release
5. High porosity of the coating surface
6. Problem with powder coating formula

Says:

1. High thickness of the coating
2. Powder spillage and accumulation on the lower edges of the piece
3. Accumulation of powder inside the corners of the piece
4. High piece temperature
5. High curing temperature

Powder spitting and wavy:

1. High concentration of powder compared to spraying air
2. Long or twisted powder hose or large hose diameter
3. Presence of moisture in powder coating
4. Pouring powder from the cabin and hangers on the surface of the piece
5. Wear of sprayer parts
6. Soft granulation of powder coating
7. Air pressure changes in the powder coating spraying system

 

Granulation of the coating surface (highness and contamination on the coated piece)

1. Fibers in cleaning wipes
2. The spray gun and hoses are not clean
3. Environmental dust pollution
4. Thinness of the final coating thickness
5. Mixing with other powder

6. Pollution caused by warehousing
7. Not properly polishing the surface of the piece, especially the cut parts

 

Orange peel:

1. Too high or too less film thickness
2. Low curing temperature
3. Wet color powder
4. Improper distribution of particle size
5. High air speed at the entrance of the furnace
6. Uneven thickness of the piece
7. High voltage
8. Lack of earth connection

Decreased color glossiness

1. Mixing incompatible colors
2. Fast and high heating during cooking
3. Mixing coating with different resin bases
4. Water and oil pollution in compressor air

 

Increasing the glossiness of matte colors

1. Incomplete cooking in the oven
2. Extreme changes in film thickness

 

Not blooming and smoothing leather and hammer colors

1. Low furnace temperature
2. The high thickness of the piece and the color coating layer
3. Color maintenance in non-standard conditions
4. Mixing the powder of smooth colors in the tank
5. Expiry date
6. Incompatibility of new and recycled coating

 

Local accumulation of hammer and metallic flowers

1. Non-uniformity of heat in the furnace
2. Imperfect earth connection
3. Strong fluctuation in the voltage of the spraying device
4. Lack of uniform color thickness
5. Alloy and metal material of the piece

 

Color change in powder color

1. Variations in furnace firing temperature
2. Low thickness of the coating layer
3. High time for the coating to cook
4. The presence of oil, water and chemical residues on the surface of the piece
5. Change in the surface type of the part
6. Contamination of the cabin and spray system and tank with previous coating

 

Weakness of coating in metallic color

1. Earth’s weakness
2. Moisture of powder coating
3. Incompatibility of new and recycled coating

 

Falling and not absorbing the powder into the piece

1. Long range of the gun
2. Dense arrangement of parts near each other
3. Low gun voltage
4. Exhaustion of the spraying device
5. High speed of conveyor line or spraying operator
6. Coarseness of color grading
7. The problem of spraying line connections

 

Soft and hard lumps in cartons

1. Lack of proper storage of powder coating (ambient temperature and humidity)
2. Non-standard shipping conditions

 

Weak powder coating of corners and piece corners

1. Increasing the air velocity in the spray gun
2. High gun voltage
3. High recycling of powder

4 Improper distance between the gun and the piece

5. Improper adjustment of the color concentration of the spray gun
6. Improper particle size distribution in powder coating
7. Weak earth connections

 

Poor fluidity of powder coating in tank or hopper

1. Existence of oil in the tank
2. Clogging of the porous plate
3. Not adjusting the wind pressure
4. The small size of the tank powder particles
5. Blockage of the air feeder
6. High humidity of powder coating

 

Production and collection: Rangin Kimia Industrial Complex

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