Part rework caused by particles attached to the surface accounts for a large part of the total part rework. The influencing factors are:
(1) There are dust and other particles on the surface of the parts after pretreatment, resulting in particles on the surface of the powder after solidification;
(2) The working environment for dusting is unclean, and dust and other particles fall on the workpiece after dusting. The drying tunnel was not cleaned for a long time, and particles fell during the powder curing process;
(3) The recovered powder is mixed with particles, and the vibrating screen of the powder box does not work (damaged or poorly sealed), causing the powder coating sprayed by the spray gun to be mixed with particles;
(4) The powder coating provided by the powder manufacturer itself contains particles such as dust and large-diameter pigments;
(5) Due to the long-term use of the powder tube or Venturi throat, the powder melts and collides with the tube wall to form individual powder skins.
(6) The hanger uses the burning method to remove the powder layer, and the dust and impurities remaining on the surface cannot be cleaned up, and they are attached to the powder layer on the surface of the parts to form particles;
(7) When the powder is wet and agglomerated, the powder supply is not uniform, and the atomization is not good, all of which can form particles on the coating film.
