a.Check the pressure of compressed air

b.Clean the air filter equipment

of compressed air

Overfill of powder in the

fluidization barrels

Blockage of gas path of

atomization or fluidization

conveying pipe because of

scaling

a.Keep periodic cleaning and replacement of powder conveying pipe after long-time use

b.Reduce the length of powder conveying pipe to the greatest extent

c.The airspeed blow of air is too high, thus heat is generated. So lower the airspeed blow or

add more guns

Wear and poor absorption

of Vuncheri powder pump

a.select powder with #80 mesh before spraying

b.store in dry and cool places at temperature below 35℃

a.Check and adjust voltage

b.Clean spear electrode and test electrode contact

High-voltage of electrostatic gun leading to insufficient spray of recesses

Powder does not adhere to re-sprayed work pieces

Insufficient grounding

Test all aspects of grounding, including gun, high-voltage generator, spray booth

and hooks. Grounding wire should be buried at least 2 meters under humid layer

Too thick dust of hanging fixtures leads to the insulation between hanging chain and hanging fixtures

Clean or replace hanging fixtures regularly

Dry air leads to Faraday effect

a.adjust gun distance to work piece, approximately 15-30cm

b.adjust gun direction to concave parts

Reduce powder output appropriately

Incomplete coating curing; not completely coating cross linking reaction

Test temperature with thermometer to inspect whether the curing parameters

reach the requirements

Over-curing leads to the decomposition of cross linking structure

Test temperature with thermometer, then lower baking temperature or shorten baking time

Poor surface treatment of work piece, e.g.

insufficient of degreasing, poor phosphating film quality, phosphating too thick,

insufficient rinse

Check processing equipment and conditioning fluid before adjustment to control the quality of phosphating film

Coating thickness too high

Adjust spray equipment to lower film thickness. It should be between 70µm and 90µm

Changes of substrate surface or substrate

type

Contact substrate manufacturer

Too long storage time leads to the reduction of reactivity

Incomplete coating curing; not completely coating cross linking reaction

Test oven temperature with thermometers to see curing curve and parameters;

increase temperature or extend curing time

Over-curing leads to the decomposition of cross linking structure. Temperature above 220℃ will easily cause bad surface hardness

Test oven temperature with thermometers; lower curing temperature appropriately or shorten curing time

Too low heat up speed; low molecular

substances migrate to coating surface, which influence the hardness

Optimize heat up speed. The usual time from room temperature to the curing

temperature is 4 to 5 minutes

Poor hardness and abrasion resistance of

powder itself

Film thickness too high or too low. Film

thickness, higher than 120u or lower than

60u, will affect coating flow

Adjust the spraying equipment to control film thickness, generally between 70 and 90μm

Optimize heat up speed. The usual time from room temperature to the curing temperature is 4 to 5 minutes

Intense back ionization effect

a.lower static voltage of spray gun

b.increase distance from work piece to gun

c.check whether the grounding system runs well

Roughness of phosphating film

Contact manufacturer to adjust formula

Incomplete coating curing

Test oven temperature with thermometers to see curing curve and parameters;increase temperature or extend curing time

Low heat up temperature of work pieces

Contamination of oven tunnel

Stop using for some time to let off evaporation

Incompatibility with other powder coating

Clean spraying equipment before replacemet of different manufacturers or different types of powder

Observe curing parameters; reduce curing temperature; shorten curing time

Contamination in the oven path, e.g. organic evaporated substances

Stop working for a certain period to eliminate evaporated substances

exclusive use or over use of reclaim powder

Contact manufacturer to improve glossiness

Coating film too thin

Increase film thickness appropriately, usually a bove 60μm

a.keep spraying house clean; clean surroundings with vacuum

b.keep workshop clean ; avoid dust and fiber

c.avoid scraps falling into the powder when pouring powder

d.Avoid clean the spray tank with paper, washcloth or brooms that will easily

lose particle

Contamination from oven path

Control the blast volume in the oven and clean oven path regularly; use high temperature resistant and anti-rust material for oven path, preferably stainless steel

Rust or dust from the chain

Rough polish then fine polish, and finally clean work pieces with compressed air

Insufficient pretreatment; phosphated

residue on substrate surfac

Mixed with small amount of low surface tension powder or material, e.g. powder containing different leveling agents or silicone oil additives

Test compatibility of powder from different manufacturers before use Clean the whole spraying system if there is incompatible powder Stop using contaminated powder and remove it out of spray houses

Check the quality of compressed air and air purification core regularly

Surrounding air contaminated, e.g. silicones,grease and dust, low surface tension evaporated material

Surrounding air contaminated, e.g. silicones, grease and dust, low surface

Oil and grease residues on work piece

Poor anti-contamination and craters of powder itself

Contact suppliers to improve powder quality

Too high or too low curing temperature;different chaining speed

Use constant curing parameters for the same work piece; check oven

Large temperature differences of different

levels of the over

Check oven temperature with oven thermometer regularly

Uneven distribution of reclaim powder in

new powder (esp. metallic powder )

Evenly add reclaim powder into new powder

The influence of voltage and airflow leads to different ascending rate of metallic pigment

Assure constant film thickness

Different types of work piece in the same drying path, especially obvious when dark color work piece and light color work piece are mixed

Poor temperature resistance and covering of the powder itself

Formula of theoretical spraying area

Spraying area ＝（1000/ weight of powder）/thickness of coating film

Control film thickness to increase spraying area (as can be seen from the above formula), usually 70-90μm

Uneven coating film because of too many

recesses of work pieces

Reduce the output of powder Spray recesses first

Heavy task of re-spraying because of low yield of first spraying

a.Reduce strength of air draft or replace with high efficient ventilation system

b.Contact suppliers to reduce fine powder content

A large proportion of powder or too much fine powder