Surface defects in powder coating spraying and corresponding measures

With the continuous progress of society, people have higher and higher requirements for the quality of life The colorful spray profiles are loved by everyone Here is a brief overview of the quality defects that are easy to appear on the surface of the spray finished products and the corresponding methods in the production process Insufficient adhesion: when the surface of the blank is not cleaned, the quality of the chromated film is unqualified, the quality of the powder itself is not qualified, the curing temperature is too low or the curing time is insufficient, it has a great impact on the coating adhesion, which requires us to strictly control the pre-treatment; the unqualified powder should be replaced in time and cured in strict accordance with the temperature and time required by the process Shrinkage cavity: generally, there are several reasons for shrinkage cavity: 1 Moisture absorption during powder storage 2 There are oil, water and other pollutants on the surface of the pretreated billet 3 The compressed air for spraying is water or oil The corresponding solutions are: keep the powder in a dry place with moderate temperature; pre treated profiles to prevent water and oil pollution during handling; design the compressed air pipeline reasonably to prevent water or oil accumulation area, and conduct secondary treatment for the compressed air if necessary The causes of uneven coating thickness are as follows: 1 Uneven powder spraying speed 2 The fluidization effect of the powder supply device is poor or the powder is wet and agglomerated 3 The conveyor chain speed is uneven The countermeasures are: to stabilize the air supply pressure, to monitor the powder quality and fluidization effect at all times, to adjust the chain speed, and to mount the profile reasonably Causes of color loss, discoloration and low gloss of coating: 1 Poor heat resistance of powder coating 2 Baking time is too long or temperature is too high 3 The interval between powder spraying and curing process is too long 4 Powder supply and spray system, recycle or mix powder of different colors and properties The countermeasures are: changing the powder with good heat exchange; shortening the baking time and temperature; curing as soon as possible after powder spraying; cleaning the powder room equipment.