The common problem of electrostatic coating spraying process is mainly caused by particles in the powder spraying environment, and other impurities caused by various factors, which are as follows:
(1) the impurities in the curing furnace. The solution is to thoroughly clean the inner wall of the furnace with wet cloth and vacuum cleaner. The key point is to hang the gap between the chain and the air duct. If it is a large black particle impurity, it is necessary to check whether there is any damaged place in the duct, and replace it in time.
(2) the impurity in the powder injection room. It is mainly dirt, clothing fibers, equipment abrasive particles and dusting system. The solution is to use compressed air to blow up the dusting system before starting work every day, and thoroughly clean the dusting equipment and dusting room with wet cloth and vacuum cleaner.
(3) suspended chain impurities. It is mainly the product of the chain suspension plate and the hoist water receiving plate (hot dip galvanized sheet) corroded by acid and caustic steam before treatment. The solution is to clean up these facilities on a regular basis.
(4) powder impurity. It is mainly due to excessive powder additives, uneven pigment distribution and powder extrusion. The solution is to improve the powder quality and improve the powder storage and transportation mode.
(5) pretreatment of impurities. It is mainly caused by large particle impurities caused by phosphating slag and small impurities caused by yellow rust of phosphating film. The solution is to clean up the slag in the phosphating tank and the spray pipe in time, and control the concentration and proportion of the phosphating bath.
(6) impurities in water quality. It is mainly the impurities caused by the amount of sand contained in the water before treatment and the excessive salt content. The solution is to increase water filters and use pure water as the last two stages of cleaning water.
(1) the shrinkage of pores caused by residual surface active agent is not treated before treatment or after washing. The solution is to control the concentration and proportion of the pre degreasing tank and the degreasing tank, reduce the oil content of the workpiece and enhance the washing effect.
(2) the shrinkage of the water caused by the excessive oil content of the water. The solution is to increase the inlet filter and prevent the oil leakage from the water supply pump.
(3) shrinkage cavity caused by excessive moisture content of compressed air. The solution is to discharge compressed air condensate in time.
(4) the shrinkage of the powder caused by the tide. The solution is to improve the storage and transportation conditions of the powder and increase the dehumidifier so as to ensure the timely use of the recovered powder.
(5) shrinkage holes caused by oil air blown to the work piece on the hanging chain. The solution is to change the position and direction of the air inlet.
(6) the shrinkage cavity caused by mixing powder. The solution is to thoroughly clean up the powder injection system when the powder is changed
Coating chromatic aberration
(1) the chromatic aberration caused by the uneven distribution of powder pigments. The solution is to improve the powder quality and ensure that the L, a and B of the powders are not very different.
(2) the chromatic aberration caused by different curing temperatures. The solution is to control the setting temperature and the speed of the conveying chain, so as to maintain the consistency and stability of the curing temperature and time of the workpiece。
(3) the chromatic aberration caused by the uneven thickness of the coating. The solution is to adjust the powder injection process parameters and ensure the powder injection equipment works well to ensure that the coating thickness is uniform.
In short, powder electrostatic spraying technology and its application are still many, and it needs to be applied flexibly in practice.